Microsoft Certified IT Professional (MCITP)
The Microsoft Certified IT Professional (MCITP) credential validates that an individual has the comprehensive set of skills necessary to perform a particular job role, such as database administrator or enterprise messaging administrator. MCITP certifications build on the technical proficiency measured in the Microsoft Certified Technology Specialist (MCTS) certifications, therefore you will earn one or more MCTS certifications on your way to earning an MCITP credential.
MCITP candidate profile
MCITP candidates are capable of deploying, building, designing, optimizing, and operating technologies for a particular job role. They make the design and technology decisions necessary to ensure successful technology implementation projects.
Why get certified?
Earning a Microsoft Certification validates your proven experience and knowledge in using Microsoft products and solutions. Designed to be relevant in today’s rapidly changing IT marketplace, Microsoft Certifications help you utilize evolving technologies, fine-tune your troubleshooting skills, and improve your job satisfaction.
Whether you are new to technology, changing jobs, or a seasoned IT professional, becoming certified demonstrates to customers, peers, and employers that you are committed to advancing your skills and taking on greater challenges. In addition, certification provides you with access to exclusive Microsoft Certified Professional (MCP) resources and benefits, including opportunities to connect with a vast, global network of MCPs
By earning an MCITP credential, you distinguish yourself as an IT professional with the skills and proven job-role capabilities to effectively work with Microsoft technologies.
Certification
Required exam(s)*
Windows Client
MCITP: Consumer Support Technician
Exam 70-620
Exam 70-623
MCITP: Enterprise Support Technician
Exam 70-620
Exam 70-622
Windows Server
MCITP: Enterprise Administrator
Exam 70-640
Exam 70-642
Exam 70-643
plus either
Exam 70-620 or Exam 70-624
and
Exam 70-647
MCITP: Server Administrator
Exam 70-640
Exam 70-642
Exam 70-646
Microsoft SQL Server
MCITP: Database Administrator 2008
Exam 70-432
Exam 70-450
MCITP: Database Developer 2008
Exam 70-433
Exam 70-451
MCITP: Business Intelligence Developer 2008
Exam 70-448
Exam 70-452
MCITP: Database Administrator
Exam 70-431
Exam 70-443
Exam 70-444
MCITP: Database Developer
Exam 70-431
Exam 70-441
Exam 70-442
MCITP: Business Intelligence Developer
Exam 70-445
Exam 70-446
Microsoft Office Project Server
MCITP: Enterprise Project Management with Microsoft Office Project Server 2007
Exam 70-632
Exam 70-633
Exam 70-634
Microsoft Exchange Server
MCITP: Enterprise Messaging Administrator
Exam 70-236
Exam 70-237
Exam 70-238
Saturday, June 19, 2010
Only for Gmail : AMAZING ONE
Only for Gmail
Now Friends the very first Trick Of Gmail that I Love the most.
So, it goes like this, say i have a email id saurav1977@gmail.com
If my Friends wants to send a mail then they will send it at this email address.
Now, Let there be three friends of mine, there may be many, just talk about three at present.
Bithika
Seema
Neeta
If i want to give my friends a unique email id
For Bithika It could be " saurav1977+ Bithika@gmail.com"
For Seema It could be " saurav1977+ Seema@gmail.com"
For Neeta It could be " saurav1977+ Neeta@gmail.com"
So, its simple you could add anything after the initial mail by adding a "+" sign.
As all these Email Addresses saurav1977+ Bithika@gmail.com, saurav1977+ Seema@gmail.com, & saurav1977+ Neeta@gmail.com are the same as saurav1977@gmail.com
If you have a girlfriend/Boyfriend then impress her/him that how much you love her/him by showing her/him name mail id.
Note: This only works when you are sending mails, Not for logging into your account.
Enjoy.....
Now Friends the very first Trick Of Gmail that I Love the most.
So, it goes like this, say i have a email id saurav1977@gmail.com
If my Friends wants to send a mail then they will send it at this email address.
Now, Let there be three friends of mine, there may be many, just talk about three at present.
Bithika
Seema
Neeta
If i want to give my friends a unique email id
For Bithika It could be " saurav1977+ Bithika@gmail.com"
For Seema It could be " saurav1977+ Seema@gmail.com"
For Neeta It could be " saurav1977+ Neeta@gmail.com"
So, its simple you could add anything after the initial mail by adding a "+" sign.
As all these Email Addresses saurav1977+ Bithika@gmail.com, saurav1977+ Seema@gmail.com, & saurav1977+ Neeta@gmail.com are the same as saurav1977@gmail.com
If you have a girlfriend/Boyfriend then impress her/him that how much you love her/him by showing her/him name mail id.
Note: This only works when you are sending mails, Not for logging into your account.
Enjoy.....
VERY IMPORTANT : GOOGLE HACKING AND SEARCHING
Introduction
lGoogle Search Technique
–Just put the word and run the search
lYou need to audit your Internet presence
–One database, Google almost has it all!
lOne of the most powerful databases in the world
lConsolidate a lot of info
lUsage:
–Student …
–Business …
–Al’Qaeda …
And Man Moreeeee.............
Google Operators:
–Operators are used to refine the results and to maximize the search value. They are your tools as well as hackers’ weapons
lBasic Operators:
+, -, ~ , ., *, “”, |, OR
lAdvanced Operators:
–allintext:, allintitle:, allinurl:, bphonebook:, cache:, define:, filetype:, info:, intext:, intitle:, inurl:, link:, phonebook:, related:, rphonebook:, site:, numrange:, daterange
BASIC OPERATORS
Basic Operators
– (+) force inclusion of something common
– Google ignores common words (where, how, digit, single letters) by default:
Example: StarStar Wars Episode +I
– (-) exclude a search term
Example: apple –red
– (“) use quotes around a search term to search exact phrases:
Example: “Robert Masse”
– Robert masse without “” has the 309,000 results, but “robert masse” only has 927 results. Reduce the 99% irrelevant results
Basic Operators
– (~) search synonym:
Example: ~food
– Return the results about food as well as recipe, nutrition and cooking information
– ( . ) a single-character wildcard:
Example: m.trix
– Return the results of M@trix, matrix, metrix…….
– ( * ) any word wildcard
– Advanced Operators: “Site:”
– Site: Domain_name
– Find Web pages only on the specified domain. If we search a specific site, usually we get the Web structure of the domain
– Examples:
site:ca
site:gosecure.ca
site:www.gosecure.ca
ADVANCE OPERATORS 1.“Intitle:”
– Intitle: search_term
– Find search term within the title of a Webpage
– Allintitle: search_term1 search_term2 search_term3
– Find multiple search terms in the Web pages with the title that includes all these words
– These operators are specifically useful to find the directory lists
– Example:
Find directory list:
Intitle: Index.of “parent directory”
ADVANCE OPERATORS 1.“Intitle:”
– Intitle: search_term
– Find search term within the title of a Webpage
– Allintitle: search_term1 search_term2 search_term3
– Find multiple search terms in the Web pages with the title that includes all these words
– These operators are specifically useful to find the directory lists
– Example:
Find directory list:
Intitle: Index.of “parent directory”
“Inurl:”
Advanced Operators “Inurl:”
– Inurl: search_term
– Find search term in a Web address
– Allinurl: search_term1 search_term2 search_term3
– Find multiple search terms in a Web address
– Examples:
Inurl: cgi-bin
Allinurl: cgi-bin password
“Intext;”
Advanced Operators “Intext;”
– Intext: search_term
– Find search term in the text body of a document.
– Allintext: search_term1 search_term2 search_term3
– Find multiple search terms in the text body of a document.
– Examples:
Intext: Administrator login
Allintext: Administrator login
“Cache:”
Advanced Operators: “Cache:”
– Cache: URL
– Find the old version of Website in Google cache
– Sometimes, even the site has already been updated, the old information might be found in cache
– Examples:
Cache: www.gosecure.com
“Daterange:”
Advanced Operators: “Daterange:”
– Daterange: -
– Find the Web pages between start date and end date
– Note: start_date and end date use the Julian date
– The Julian date is calculated by the number of days since January 1, 4713 BC. For example, the Julian date for August 1, 2001 is 2452122
– Examples:
2004.07.10=2453196
2004.08.10=2453258
– Vulnerabilities date range: 2453196-2453258
“Link:”
Advanced Operators “Link:”
– Link: URL
– Find the Web pages having a link to the specified URL
– Related: URL
– Find the Web pages that are “similar” to the specified Web page
– info: URL
– Present some information that Google has about that Web page
– Define: search_term
– Provide a definition of the words gathered from various online sources
– Examples:
Link: gosecure.ca
Related: gosecure.ca
Info: gosecure.ca
Define: Network security
“phonebook:”
Advanced Operators “phonebook:”
– Phonebook
– Search the entire Google phonebook
– rphonebook
– Search residential listings only
– bphonebook
– Search business listings only
– Examples:
Phonebook: robert las vegas (robert in Las Vegas)
Phonebook: (702) 944-2001 (reverse search, not always work)
The phonebook is quite limited to U.S.A
Google, Friend or Enemy?
Google, Friend or Enemy?
– Google is everyone’s best friend (yours or hackers)
– Information gathering and vulnerability identification are the tasks in the first phase of a typical hacking scenario
– Passitive, stealth and huge data collection
– Google can do more than search
– Have you used Google to audit your organization today?
What can Google can do for a hacker?
– Search sensitive information like payroll, SIN, even the personal email box
– Vulnerabilities scanner
– Transparent proxy
Salary
– Salary filetype: xls site: edu
Security social insurance number
– Intitle: Payroll intext: ssn filetype: xls site: edu
Financial Information
– Filetype: xls “checking account” “credit card” - intext: Application -intext: Form
Personal Mailbox
– Intitle: Index.of inurl: Inbox
Confidential Files
– “not for distribution” confidential
Google Hacking
Usually it takes a very long time to find something on google search, but isn’t it wonderful if you directly find the same whatever you want just by adding few more characters.
1. If you making a project for your school or for your collage then it will really very helpful if you got few e-books on the same topic. Say, if you are making a project over the topic ‘Networking’. Then go to google search and type networking filetype:pdf
2. If you are looking for your project materials in Doc file then use networking filetype:doc
3. If you are looking for any presentation on the topic networking then use networking filetype:ppt
4. And if you are a music freak and don’t want to waste time on surfing the whole internet just for your favorite song then try using this ?intitle:index.of? mp3 enrique . This search will show you all mp3 songs of Enrique all together and free of cost.
5. If you are a little bit computer conscious and want disc images of various operating systems and of games then try this inurl:vista filetype:iso . This search will give you download link of images of windows Vista.
GOOGLE HACKING REFERENCES
Google APIS:
www.google.com/apis
Remove:
http://www.google.com/remove.html
Googledorks:
http://johnny.ihackstuff.com/
O’reilly Google Hack:
http://www.oreilly.com/catalog/googlehks/
Google Hack Presentation, Jonhnny Long:
http://johnny.ihackstuff.com/modules.php?op=modload&name= ownloads&file=index&req=viewdownload&cid=1
“Autism: Using google to hack:
www.smart-dev.com/texts/google.txt
“Google: Net Hacker Tool du Jour:
http://www.wired.com/news/infostructure/0,1377,57897,00.html
lGoogle Search Technique
–Just put the word and run the search
lYou need to audit your Internet presence
–One database, Google almost has it all!
lOne of the most powerful databases in the world
lConsolidate a lot of info
lUsage:
–Student …
–Business …
–Al’Qaeda …
And Man Moreeeee.............
Google Operators:
–Operators are used to refine the results and to maximize the search value. They are your tools as well as hackers’ weapons
lBasic Operators:
+, -, ~ , ., *, “”, |, OR
lAdvanced Operators:
–allintext:, allintitle:, allinurl:, bphonebook:, cache:, define:, filetype:, info:, intext:, intitle:, inurl:, link:, phonebook:, related:, rphonebook:, site:, numrange:, daterange
BASIC OPERATORS
Basic Operators
– (+) force inclusion of something common
– Google ignores common words (where, how, digit, single letters) by default:
Example: StarStar Wars Episode +I
– (-) exclude a search term
Example: apple –red
– (“) use quotes around a search term to search exact phrases:
Example: “Robert Masse”
– Robert masse without “” has the 309,000 results, but “robert masse” only has 927 results. Reduce the 99% irrelevant results
Basic Operators
– (~) search synonym:
Example: ~food
– Return the results about food as well as recipe, nutrition and cooking information
– ( . ) a single-character wildcard:
Example: m.trix
– Return the results of M@trix, matrix, metrix…….
– ( * ) any word wildcard
– Advanced Operators: “Site:”
– Site: Domain_name
– Find Web pages only on the specified domain. If we search a specific site, usually we get the Web structure of the domain
– Examples:
site:ca
site:gosecure.ca
site:www.gosecure.ca
ADVANCE OPERATORS 1.“Intitle:”
– Intitle: search_term
– Find search term within the title of a Webpage
– Allintitle: search_term1 search_term2 search_term3
– Find multiple search terms in the Web pages with the title that includes all these words
– These operators are specifically useful to find the directory lists
– Example:
Find directory list:
Intitle: Index.of “parent directory”
ADVANCE OPERATORS 1.“Intitle:”
– Intitle: search_term
– Find search term within the title of a Webpage
– Allintitle: search_term1 search_term2 search_term3
– Find multiple search terms in the Web pages with the title that includes all these words
– These operators are specifically useful to find the directory lists
– Example:
Find directory list:
Intitle: Index.of “parent directory”
“Inurl:”
Advanced Operators “Inurl:”
– Inurl: search_term
– Find search term in a Web address
– Allinurl: search_term1 search_term2 search_term3
– Find multiple search terms in a Web address
– Examples:
Inurl: cgi-bin
Allinurl: cgi-bin password
“Intext;”
Advanced Operators “Intext;”
– Intext: search_term
– Find search term in the text body of a document.
– Allintext: search_term1 search_term2 search_term3
– Find multiple search terms in the text body of a document.
– Examples:
Intext: Administrator login
Allintext: Administrator login
“Cache:”
Advanced Operators: “Cache:”
– Cache: URL
– Find the old version of Website in Google cache
– Sometimes, even the site has already been updated, the old information might be found in cache
– Examples:
Cache: www.gosecure.com
“Daterange:”
Advanced Operators: “Daterange:”
– Daterange: -
– Find the Web pages between start date and end date
– Note: start_date and end date use the Julian date
– The Julian date is calculated by the number of days since January 1, 4713 BC. For example, the Julian date for August 1, 2001 is 2452122
– Examples:
2004.07.10=2453196
2004.08.10=2453258
– Vulnerabilities date range: 2453196-2453258
“Link:”
Advanced Operators “Link:”
– Link: URL
– Find the Web pages having a link to the specified URL
– Related: URL
– Find the Web pages that are “similar” to the specified Web page
– info: URL
– Present some information that Google has about that Web page
– Define: search_term
– Provide a definition of the words gathered from various online sources
– Examples:
Link: gosecure.ca
Related: gosecure.ca
Info: gosecure.ca
Define: Network security
“phonebook:”
Advanced Operators “phonebook:”
– Phonebook
– Search the entire Google phonebook
– rphonebook
– Search residential listings only
– bphonebook
– Search business listings only
– Examples:
Phonebook: robert las vegas (robert in Las Vegas)
Phonebook: (702) 944-2001 (reverse search, not always work)
The phonebook is quite limited to U.S.A
Google, Friend or Enemy?
Google, Friend or Enemy?
– Google is everyone’s best friend (yours or hackers)
– Information gathering and vulnerability identification are the tasks in the first phase of a typical hacking scenario
– Passitive, stealth and huge data collection
– Google can do more than search
– Have you used Google to audit your organization today?
What can Google can do for a hacker?
– Search sensitive information like payroll, SIN, even the personal email box
– Vulnerabilities scanner
– Transparent proxy
Salary
– Salary filetype: xls site: edu
Security social insurance number
– Intitle: Payroll intext: ssn filetype: xls site: edu
Financial Information
– Filetype: xls “checking account” “credit card” - intext: Application -intext: Form
Personal Mailbox
– Intitle: Index.of inurl: Inbox
Confidential Files
– “not for distribution” confidential
Google Hacking
Usually it takes a very long time to find something on google search, but isn’t it wonderful if you directly find the same whatever you want just by adding few more characters.
1. If you making a project for your school or for your collage then it will really very helpful if you got few e-books on the same topic. Say, if you are making a project over the topic ‘Networking’. Then go to google search and type networking filetype:pdf
2. If you are looking for your project materials in Doc file then use networking filetype:doc
3. If you are looking for any presentation on the topic networking then use networking filetype:ppt
4. And if you are a music freak and don’t want to waste time on surfing the whole internet just for your favorite song then try using this ?intitle:index.of? mp3 enrique . This search will show you all mp3 songs of Enrique all together and free of cost.
5. If you are a little bit computer conscious and want disc images of various operating systems and of games then try this inurl:vista filetype:iso . This search will give you download link of images of windows Vista.
GOOGLE HACKING REFERENCES
Google APIS:
www.google.com/apis
Remove:
http://www.google.com/remove.html
Googledorks:
http://johnny.ihackstuff.com/
O’reilly Google Hack:
http://www.oreilly.com/catalog/googlehks/
Google Hack Presentation, Jonhnny Long:
http://johnny.ihackstuff.com/modules.php?op=modload&name= ownloads&file=index&req=viewdownload&cid=1
“Autism: Using google to hack:
www.smart-dev.com/texts/google.txt
“Google: Net Hacker Tool du Jour:
http://www.wired.com/news/infostructure/0,1377,57897,00.html
USERNAME AND PASSWORD : VERY IMPORTANT
THIS BLOG IS FOR EDUCATIONAL PURPOSE ONLY :
USERNAME AND PASSWORD
Search Username
– +intext: "webalizer" +intext: “Total Usernames” +intext: “Usage Statistics for”
Search Passwords
– Search the well known password filenames in URL
– Search the database connection files or configuration files to find a password and username
– Search specific username file for a specific product
– Inurl: etc inurl: passwd
– Intitle: “Index of..etc” passwd
– "# -FrontPage-" inurl: service.pwd (then crack it)
– Inurl: admin.pwd filetype: pwd
– Filetype: inc dbconn
– Filetype: inc intext: mysql_connect
– Filetype: ini +ws_ftp +pwd (get the encrypted passwords)
– Filetype: log inurl: “password.log
USERNAME AND PASSWORD
Search Username
– +intext: "webalizer" +intext: “Total Usernames” +intext: “Usage Statistics for”
Search Passwords
– Search the well known password filenames in URL
– Search the database connection files or configuration files to find a password and username
– Search specific username file for a specific product
– Inurl: etc inurl: passwd
– Intitle: “Index of..etc” passwd
– "# -FrontPage-" inurl: service.pwd (then crack it)
– Inurl: admin.pwd filetype: pwd
– Filetype: inc dbconn
– Filetype: inc intext: mysql_connect
– Filetype: ini +ws_ftp +pwd (get the encrypted passwords)
– Filetype: log inurl: “password.log
Google services
(1) Google Labs
My favourite online playground (although the offerings at the moment are a little dull). This is where new Google products are first given the beta label and unleashed onto an unsuspecting world for testing and commenting. If you try something out in Google Labs, you are invited to email the Google team involved with comments / suggestions / complaints (on two occasions, I got a personal reply back from a member of the team, discussing my comments).
The way I see it, this is a good way to influence future Google products by getting involved in a product’s development. How many Google users use Google products but don’t bother to provide any creative input to make them better? Next time a Google product doesn’t go as planned, don’t complain on a forum - contact Google and offer constructive advice & criticism!
(2) Google Pack
If you know an internet newbie who has not so much knowledge of the internet and software products (like my mother), Google Pack provides an excellent software package to start with (although I personally wouldn’t choose Norton and Real Player). Check out full program list here.
(3) Google Translate
Translate text or even complete webpages into eleven languages (you can even translate from “simplified” Chinese to “traditional” Chinese). As with all online translators, this won’t give you a 100% accurate translation (online translators can’t grasp things like idioms and contexts) but if you want to buy those crates of AK-47 assault rifles from that online shop in North Korea, Google Translate will let you overcome that Korean language barrier.
(4) Google Co-Op
Allows you to customize Google search results with your own self-rolled search engines. You can also provide information from your website as a subscribed link or if you are a specialist in a particular subject area, you can label and categorize search information which other people can click on. Again, this is another way you can actively help in making search much better (otherwise known as user-generated input).
(5) Google Code
This one is for the computer geeks (of which I am a honorary member). Allows you to find and download source codes and developer API’s to make mashups for Google products.
(6) Google News
Google News has been around for a while and is old-hat to many. But how many of you knew that you could customise the page to only see the news you want to see? Or the fact you can set up customised RSS feeds for the news subjects that interest you? Never miss another news story about Paris Hilton ever again. You can also use the new news archive to find very old news stories, either scanned pages of publications or online sources. Some free, others not.
(7) Google Patent Search
If you’re in business and you’ve developed a hot new invention, don’t you want to check first to see if anybody got in there before you and filed a patent? Google Patent Search will show you the patent applications for pretty much everything so you can see right away if you are the sole inventor of the combined coat hanger and cigarette lighter.
(8) Google Blog Search
One of my personal favourites as it helps me to find current blogs on my favourite subjects (and swell my 200+ RSS reading list even further). Find blogs catering to various subjects. Want to know if anybody shares your overwhelming passion for navel lint by blogging about it? GBS will help you out.
(9) Google Alerts
Want to know if anybody has been talking about you online? Maybe somebody trashed your website by insulting it in a forum? Or a disgruntled customer to your online shop made disparaging remarks in their blog? By setting up a Google Alert (with pre-defined search terms), you will get an email with links anytime Google finds something matching your keywords. Britney Spears probably has one set up now with the keywords “Britney” and “MTV Music Awards”.
(10) Google Catalogs
Guys rejoice! (and women too). Want to buy some Victoria’s Secret lingerie? Or perhaps a new light-sabre is in order for you trusty Jedi Knights? Google now offers the chance to browse through scanned pages of catalogs and magazines such as GQ and Cosmopolitan to find products you might be looking for. No more raking in bins looking for catalogs of women in bikinis - Google now gives them to you online!
My favourite online playground (although the offerings at the moment are a little dull). This is where new Google products are first given the beta label and unleashed onto an unsuspecting world for testing and commenting. If you try something out in Google Labs, you are invited to email the Google team involved with comments / suggestions / complaints (on two occasions, I got a personal reply back from a member of the team, discussing my comments).
The way I see it, this is a good way to influence future Google products by getting involved in a product’s development. How many Google users use Google products but don’t bother to provide any creative input to make them better? Next time a Google product doesn’t go as planned, don’t complain on a forum - contact Google and offer constructive advice & criticism!
(2) Google Pack
If you know an internet newbie who has not so much knowledge of the internet and software products (like my mother), Google Pack provides an excellent software package to start with (although I personally wouldn’t choose Norton and Real Player). Check out full program list here.
(3) Google Translate
Translate text or even complete webpages into eleven languages (you can even translate from “simplified” Chinese to “traditional” Chinese). As with all online translators, this won’t give you a 100% accurate translation (online translators can’t grasp things like idioms and contexts) but if you want to buy those crates of AK-47 assault rifles from that online shop in North Korea, Google Translate will let you overcome that Korean language barrier.
(4) Google Co-Op
Allows you to customize Google search results with your own self-rolled search engines. You can also provide information from your website as a subscribed link or if you are a specialist in a particular subject area, you can label and categorize search information which other people can click on. Again, this is another way you can actively help in making search much better (otherwise known as user-generated input).
(5) Google Code
This one is for the computer geeks (of which I am a honorary member). Allows you to find and download source codes and developer API’s to make mashups for Google products.
(6) Google News
Google News has been around for a while and is old-hat to many. But how many of you knew that you could customise the page to only see the news you want to see? Or the fact you can set up customised RSS feeds for the news subjects that interest you? Never miss another news story about Paris Hilton ever again. You can also use the new news archive to find very old news stories, either scanned pages of publications or online sources. Some free, others not.
(7) Google Patent Search
If you’re in business and you’ve developed a hot new invention, don’t you want to check first to see if anybody got in there before you and filed a patent? Google Patent Search will show you the patent applications for pretty much everything so you can see right away if you are the sole inventor of the combined coat hanger and cigarette lighter.
(8) Google Blog Search
One of my personal favourites as it helps me to find current blogs on my favourite subjects (and swell my 200+ RSS reading list even further). Find blogs catering to various subjects. Want to know if anybody shares your overwhelming passion for navel lint by blogging about it? GBS will help you out.
(9) Google Alerts
Want to know if anybody has been talking about you online? Maybe somebody trashed your website by insulting it in a forum? Or a disgruntled customer to your online shop made disparaging remarks in their blog? By setting up a Google Alert (with pre-defined search terms), you will get an email with links anytime Google finds something matching your keywords. Britney Spears probably has one set up now with the keywords “Britney” and “MTV Music Awards”.
(10) Google Catalogs
Guys rejoice! (and women too). Want to buy some Victoria’s Secret lingerie? Or perhaps a new light-sabre is in order for you trusty Jedi Knights? Google now offers the chance to browse through scanned pages of catalogs and magazines such as GQ and Cosmopolitan to find products you might be looking for. No more raking in bins looking for catalogs of women in bikinis - Google now gives them to you online!
GOOGLE ROCKS!!!
GOOGLE ROCKS!!!
I wanted to write on something but couldn’t think of any topic to write on. So I thought of writing on one of the biggest boon to people using Internet. No prizes for guessing the name. It’s undoubtedly THE GOOGLE. Without The Google life would have been difficult for Internet surfers. Google is the leading web company and the only software company that can give tough competition to The Microsoft. The one big worry that Bill Gates has is the success of google. It’s haunting his night’s sleep.
Google. This word that has been derived from the word googol means 10100 fits the goal of the google in building a large-scale search engine that can index as much as 10100 web pages online.The Google was initially a research project by two students from Stanford University called Larry Page and Sergey Brin. They not even in their wildest dreams would have thought that Google would do so well. The Google was initially called BackRub because of its unique ability to analyze the “back links” pointing to a given website. A complete anatomy of this search engine is beyond the scope of this blog and beyond my head as well. However if you want it you can mail me. Soon this BackRub earned a reputation due to its efficiency. Larry and Sergey continued to work to perfect their technology and by 1998 it was all done. The next worry that they had was that they needed the investors to invest on their potent search-engine. They soon got their first investor who was also a faculty member of Stanford and one of the founders of Sun Microsystems, Andy Bechtolsheim. He gave them a check of $100,000 and rest as they say is history. After that there hasn’t been any looking back for the Google.
Google is the company that every student wants to join and why not after all anybody would love to live in the luxurious Googleplex. Once you join google your life is like a heaven in Googleplex. But as they say, there are no free lunches in this world; it’s very difficult to get a job in google. They just select the best among the bests. But you can still dream to be in it, after all dreams do not cost you a penny.
Google has dominated almost every aspects of World Wide Web. Nowadays google doesn’t mean just a search engine. Now it has pioneered various other web services as well. You can just simply do everything with google. You can search anything with the help of its search engine. Its mailing service g-mail is better than that of yahoo and hotmail. It’s social networking website ORKUT has become a very important part of the youngsters life. I personally know many people who just cannot stay without ORKUT. If you want to download any video or songs then just go for YOUTUBE. It’s probably the best in this business. If you want to share your thoughts with people living anywhere in this world you can do this by using what it is called BLOGGER. You can create your web page and that too for free. With google, I guess there are some free lunches in this world. There are also other features like Adsense and Adwords that can make you earn through your website. It’s like getting almost everything from google and that too just by paying nothing.Google has really revolutionized our lives and its first of its kind that gives you almost everything and that too just for free. Although it earns through its advertisers but the best part is that we don’t need to pay anything.
So we come to the end of this post. It was just a short description on google. Just mail me with questions, suggestions, comments or simply anything. Goodbye! And have fun with technology.
I wanted to write on something but couldn’t think of any topic to write on. So I thought of writing on one of the biggest boon to people using Internet. No prizes for guessing the name. It’s undoubtedly THE GOOGLE. Without The Google life would have been difficult for Internet surfers. Google is the leading web company and the only software company that can give tough competition to The Microsoft. The one big worry that Bill Gates has is the success of google. It’s haunting his night’s sleep.
Google. This word that has been derived from the word googol means 10100 fits the goal of the google in building a large-scale search engine that can index as much as 10100 web pages online.The Google was initially a research project by two students from Stanford University called Larry Page and Sergey Brin. They not even in their wildest dreams would have thought that Google would do so well. The Google was initially called BackRub because of its unique ability to analyze the “back links” pointing to a given website. A complete anatomy of this search engine is beyond the scope of this blog and beyond my head as well. However if you want it you can mail me. Soon this BackRub earned a reputation due to its efficiency. Larry and Sergey continued to work to perfect their technology and by 1998 it was all done. The next worry that they had was that they needed the investors to invest on their potent search-engine. They soon got their first investor who was also a faculty member of Stanford and one of the founders of Sun Microsystems, Andy Bechtolsheim. He gave them a check of $100,000 and rest as they say is history. After that there hasn’t been any looking back for the Google.
Google is the company that every student wants to join and why not after all anybody would love to live in the luxurious Googleplex. Once you join google your life is like a heaven in Googleplex. But as they say, there are no free lunches in this world; it’s very difficult to get a job in google. They just select the best among the bests. But you can still dream to be in it, after all dreams do not cost you a penny.
Google has dominated almost every aspects of World Wide Web. Nowadays google doesn’t mean just a search engine. Now it has pioneered various other web services as well. You can just simply do everything with google. You can search anything with the help of its search engine. Its mailing service g-mail is better than that of yahoo and hotmail. It’s social networking website ORKUT has become a very important part of the youngsters life. I personally know many people who just cannot stay without ORKUT. If you want to download any video or songs then just go for YOUTUBE. It’s probably the best in this business. If you want to share your thoughts with people living anywhere in this world you can do this by using what it is called BLOGGER. You can create your web page and that too for free. With google, I guess there are some free lunches in this world. There are also other features like Adsense and Adwords that can make you earn through your website. It’s like getting almost everything from google and that too just by paying nothing.Google has really revolutionized our lives and its first of its kind that gives you almost everything and that too just for free. Although it earns through its advertisers but the best part is that we don’t need to pay anything.
So we come to the end of this post. It was just a short description on google. Just mail me with questions, suggestions, comments or simply anything. Goodbye! And have fun with technology.
Google's GDrive Could Replace your Hard Disk
This drive will allow users to save their data online and users will be able to access their data from any computer in the world
Taking cloud computing to a new level, Google is soon going to launch 'GDrive', a long-rumored online storage for its users.
GDrive would work as an online hard disk and could essentially work as a syncing device that will periodically update itself with the activities that take place on a computer, the Google Operating System has discovered.
Also discovered in a Google Apps CSS file is that there is reportedly an update for Google Docs on the way that would include a desktop client for syncing files with GDrive.
Since this drive will allow users to save their data online, users will be able to access their data from any computer in the world, as long as it is connected to an internet connection.
In fact, if you take Google provisions seriously, you've probably already shifted your photograph and document base to atleast one of the Google services that work as great archiving hubs. However, space restriction and reliability could be a user's concern while depending on the Google servers to save their precious data.
The GDrive could also partially replace the physical hard disk that a user needs to select an operating system (OS) for usage -- that is, after the initial booting. Google's online hard drive will merge all of Google's web based applications and make them available together.
================================
Internet giant Google plans to launch its Google Drive service, which could make PCs obsolete. The GDrive would allow users to access their personal computers from any Internet connection, eliminating the need for a hard drive. But some privacy experts are concerned about users storing personal files on Google's servers. Observer (London), The (01/25)
Taking cloud computing to a new level, Google is soon going to launch 'GDrive', a long-rumored online storage for its users.
GDrive would work as an online hard disk and could essentially work as a syncing device that will periodically update itself with the activities that take place on a computer, the Google Operating System has discovered.
Also discovered in a Google Apps CSS file is that there is reportedly an update for Google Docs on the way that would include a desktop client for syncing files with GDrive.
Since this drive will allow users to save their data online, users will be able to access their data from any computer in the world, as long as it is connected to an internet connection.
In fact, if you take Google provisions seriously, you've probably already shifted your photograph and document base to atleast one of the Google services that work as great archiving hubs. However, space restriction and reliability could be a user's concern while depending on the Google servers to save their precious data.
The GDrive could also partially replace the physical hard disk that a user needs to select an operating system (OS) for usage -- that is, after the initial booting. Google's online hard drive will merge all of Google's web based applications and make them available together.
================================
Internet giant Google plans to launch its Google Drive service, which could make PCs obsolete. The GDrive would allow users to access their personal computers from any Internet connection, eliminating the need for a hard drive. But some privacy experts are concerned about users storing personal files on Google's servers. Observer (London), The (01/25)
GOOGLE TOOLS :
MATERIALS
Google Automated Tools
– SiteDigger
– SiteDigger searches Google’s cache to look for vulnerabilities, errors, configuration issues, proprietary information, and interesting security nuggets on Web sites. See: http://www.foundstone.com
Google Materials
– Googledorks
– The famous Google Hack Website, it has many different examples of unbelievable things: http://johnny.ihackstuff.com.
Google Automated Tools
– SiteDigger
– SiteDigger searches Google’s cache to look for vulnerabilities, errors, configuration issues, proprietary information, and interesting security nuggets on Web sites. See: http://www.foundstone.com
Google Materials
– Googledorks
– The famous Google Hack Website, it has many different examples of unbelievable things: http://johnny.ihackstuff.com.
A list of google sites…
A list of google sites…No wonder I’m a google Fan
I love google,because they are open to all…..
Google
Google Scholar
Google Adsense
Google Adwords
Google Earth
Google Tool Bar for Firefox
Google Tool Bar for IE
Google Local
Google Froogle
Google Submit your Site
Google Satellite Pictures
Google Base
Google News
Google Groups
Google Blog
Google Blogger
Google Blog Search
Google Desktop
Google Print
Google Book Search
Google Image
Google Search
Google Search Cheat Sheet
Google Advanced Search
Google Talk
Google Gmail
Google Video
Google Alert
Google Finance
Google US Government Search
Google Linux Search
Google BSD Search
Google Mac/Apple Search
Google Microsoft Search
Google Web Search
Google Picasa
Google Translator
Google Page Creator
Google Dashboard Widgets for Mac
Google Blogger Web Comments Extension
Google Send to Phone
Google Transit
Google Reader
Google Web Accelerator
Google Ride Finder
Google Suggest
Google Site-Flavored Search Box
Google Froogle Mobile US
Google Froogle Mobile UK
Google Compute
Google Sets
Google Personalized Search
Google Pesonalized Homepage
Google SMS US
Google SMS UK
Google Glossary
Google Research Publications
Google Mars
Google Analytics
Google Local Business Center
Google Frugal Seller Services
Google Sitemaps
Google Video Upload
Google Books Partner
Google Mobile Partner
Google Gulp
Google Mini
Google Desktop Enterprise Edition
Google Toolbar Enterprise
Google Search Appliance
Google Store
Google Press Center
Google Jobs
Google Inside Google
Google Holiday Logos
Google Official Logos
Google Fan Logos
Google Investor Relations
Contact Google
Google Security Issues
Google Orkut
Google Permissions
Google Webmaster Info
Google Cached Links
Google Calculator
Google Currency Converter
Google Definitions
Google File Types
Google I’m Feeling Lucky
Google Movies
Google Music Search
Google News Headlines
Google Phonebook
Google Q&A
Google Search by Number
Google Site Search
Google Spell Checker
Google Stock Quotes
Google Travel Info
Google Weather
Google Who Links to You?
Google Pack
Google Newsletter
Google-Friends Newsletter Archive
Google Mobile
Google Code
Google Goopy
Google Explorer Canvas
Google Kongulo
Google LibJingle
Google Blogger for Word
Google Writely
Google Sketchup
Google Moms
Google Moms 2
Google Calender
Google Gum
Google Video Top 100
Google Da Vinci Code Quest
Google Romance
Google Why Use (Hacker Edition)
Google Search for Hackers
Google 3 Billion Milestone
Google Lucky
Google Registry Files 1 / 2
Google Current Communications
Google ????
Google Small Search
Google for IE Research
Google Elements Stats
Google Translate (Simple)
Google Loading
Google Reset
Google MentalPlex
Google University Search
Google Media Room
Google Milestones
Google Executives
Google Sitemap
Google
I love google,because they are open to all…..
Google Scholar
Google Adsense
Google Adwords
Google Earth
Google Tool Bar for Firefox
Google Tool Bar for IE
Google Local
Google Froogle
Google Submit your Site
Google Satellite Pictures
Google Base
Google News
Google Groups
Google Blog
Google Blogger
Google Blog Search
Google Desktop
Google Print
Google Book Search
Google Image
Google Search
Google Search Cheat Sheet
Google Advanced Search
Google Talk
Google Gmail
Google Video
Google Alert
Google Finance
Google US Government Search
Google Linux Search
Google BSD Search
Google Mac/Apple Search
Google Microsoft Search
Google Web Search
Google Picasa
Google Translator
Google Page Creator
Google Dashboard Widgets for Mac
Google Blogger Web Comments Extension
Google Send to Phone
Google Transit
Google Reader
Google Web Accelerator
Google Ride Finder
Google Suggest
Google Site-Flavored Search Box
Google Froogle Mobile US
Google Froogle Mobile UK
Google Compute
Google Sets
Google Personalized Search
Google Pesonalized Homepage
Google SMS US
Google SMS UK
Google Glossary
Google Research Publications
Google Mars
Google Analytics
Google Local Business Center
Google Frugal Seller Services
Google Sitemaps
Google Video Upload
Google Books Partner
Google Mobile Partner
Google Gulp
Google Mini
Google Desktop Enterprise Edition
Google Toolbar Enterprise
Google Search Appliance
Google Store
Google Press Center
Google Jobs
Google Inside Google
Google Holiday Logos
Google Official Logos
Google Fan Logos
Google Investor Relations
Contact Google
Google Security Issues
Google Orkut
Google Permissions
Google Webmaster Info
Google Cached Links
Google Calculator
Google Currency Converter
Google Definitions
Google File Types
Google I’m Feeling Lucky
Google Movies
Google Music Search
Google News Headlines
Google Phonebook
Google Q&A
Google Search by Number
Google Site Search
Google Spell Checker
Google Stock Quotes
Google Travel Info
Google Weather
Google Who Links to You?
Google Pack
Google Newsletter
Google-Friends Newsletter Archive
Google Mobile
Google Code
Google Goopy
Google Explorer Canvas
Google Kongulo
Google LibJingle
Google Blogger for Word
Google Writely
Google Sketchup
Google Moms
Google Moms 2
Google Calender
Google Gum
Google Video Top 100
Google Da Vinci Code Quest
Google Romance
Google Why Use (Hacker Edition)
Google Search for Hackers
Google 3 Billion Milestone
Google Lucky
Google Registry Files 1 / 2
Google Current Communications
Google ????
Google Small Search
Google for IE Research
Google Elements Stats
Google Translate (Simple)
Google Loading
Google Reset
Google MentalPlex
Google University Search
Google Media Room
Google Milestones
Google Executives
Google Sitemap
60 TOOLS + RESOURCES BY GOOGLE
With Google announcing the ability to increase your Gmail storage capacity this week, we decided to delve into other ways to extend and enhance Google’s popular webmail service. Presenting: 60+ tools and resources for Gmail.
Desktop Applications
GCount - An application for Mac OSX that alerts you to new mail.
gDisk - An app for Mac OSX giving the ability to turn Gmail accounts into storage drives.
gFeeder - A small ticker for your Gmail that will let you know at a glance what’s coming in for you.
GetMail - Allows you to migrate your emails from Hotmail to your Gmail account.
Gmail Drive - Another tool for turning your Gmail account in to a virtual storage drive, this one works directly from inside Windows Explorer.
Gmail Loader - For Windows or Linux, aids you in loading your email to your Gmail account.
GMailFS - Turns your Gmail space into a virtual drive that your Windows Explorer can see.
GotMailG - A Mac widget to display the number of unread messages in your inbox.
POP3/IMAP server for GMAIL in JAVA - Allows you POP3 access via your favorite mail reader to your Gmail account, IMAP still in development.
Send To GMail - With one click, you can back up any file you want from your computer to your Gmail account.
Firefox Tools
Better Gmail - Combines some of the most popular Greasemonkey scripts in to one extension. Includes things such as skins, saved searches, keyboard macros, and more.
Delegate to Remember The Milk - Adds a button to Gmail and allows you make to-do lists.
Dragdropupload - Allows you to drag your files to the attachment box.
GCalQuickTab - Allows you to quickly change between Google Mail and Calendar with keyboard shortcuts.
Gmail Checker - Allows you to check your Gmail for new messages.
Gmail Manager - Allows you to not only manage multiple accounts, but know how much mail and spam they have.
Gmail Notifier - Get notifications of new emails right in your browser.
Gmail RTL - Adds direction buttons to your email.
Gmail S/Mime - Allows you to send and receive encrypted emails.
Gmail Skins - Change the look of your inbox, insert HTML tables, use emoticons and more.
Google Toolbar - Official Google release of a toolbar with Gmail features.
Gspace - Turns your Gmail account in to a virtual web drive that you can upload files to and store them.
gTalk Sidebar - Incorporates Google Talk into your sidebar.
GTDInBox - A Getting Things Done tool that integrates into Gmail, helps you get organized.
WebMail Notifier - Checks your Gmail account for unread emails; works with other email services also.
Greasemonkey Scripts
Clean Gmail Print - Removes the Gmail logo when you go to print out your email
Folders4Gmail - If you prefer the old style of sorting mail in folders over labels, this is the script for you.
Force HTTPS for GMail, GCal, and GDocs - Forces the corner links in the Google apps to change over to HTTPS.
gDate2Cal 0.1 - Turns dates in Gmail in to links to take you to that day in Google Calendar.
Gmail + Reader Integration - Lets you use Google Reader with your Gmail account.
GMail Attachment Icons - Shows you an icon that lets you know what type of file is attached to an email without opening it.
Gmail attachment reminder v2.4.1 - Reminds you to attach a file your email if it appears you haven’t.
Gmail Contact List - Adds a contact list near the “To” field in compose.
Gmail Conversation Preview - Right click on a conversation to get a preview of it in a bubble.
Gmail Date Search - adds a Search by Date button to Gmail’s search form
Gmail Delete Button - RED Color - Turns the delete button red so there is less chance of hitting it accidentally.
Gmail Emoticons! - Puts an emoticons button next to the “Check Spelling” button to allow you to enter numerous different smilies.
Gmail Encrypt - Allows you to encrypt outgoing emails and create encryption keys.
Gmail FavIcon Alerts - Turns the Gmail favicon in the address bar in to a new mail alert.
Gmail from address selector - Lets you change the reply-to email address depending on who you are sending to. (i.e. sending to someone like “@work.com”, you choose your work address as the from address)
Gmail Full Width - Removes the advertising block on the right so that your mails take up the full width.
Gmail Google Calendar sidebar - Adds your Google Calendar to your Gmail display.
Gmail Lite - Removes ads, the footer, stars, and chats.
Gmail Macros - Allows you to create more keyboard shortcuts to speed up your Gmail experience.
Gmail Multi-User Login - For those of you with more than one Gmail account, this will give you a drop down menu with all of your accounts listed.
Gmail Multiple Signatures, plus Float - Will change your signature based on what return address you enter.
Gmail - One Click Conversations - Allows you quick access to the most recent conversations with a contact via a one click button.
GMail Header, Navigation and Ads Switcher - Can choose to hide or show the header, navigation bar, and ads by clicking a button.
Gmail - Zip Attachments and Download - Allows you to download all the attachments of an email by merely clicking on the paper clip icon.
GmailTo -Opens mailto: commands from websites in Gmail compose.
Google Air Skin - Script to use Air Skin in Gmail, Google Calendar, on Google.com, and Google Reader.
Label Colors - Lets you choose the colors of various labels so you can tell them apart easier.
Plaxo4Gmail - Allows you to sync your Gmail with your Plaxo info.
Saved Searches - Allows you to save a Gmail search so that you can just click on the saved search to do it again.
Miscellaneous
GBooks - Allows you to turn a Gmail account in to a bookmarks server.
gExodus - Allows you to export your emails from another account to your Gmail account in mbox format.
Gmail icon generator - Allows you to create a small graphic of your Gmail address to place on websites so that you may display your address without spam bots reading it.
Gmail Music - Store MP3 files in your Gmail account and play them on any computer.
Gmail Todo - Turn your Gmail into a helpful “To Do” list.
PhpGmailDrive - Retrieves a list of attachments from a Gmail account and enables you to list them on a website or blog for others to download.
You’ve Got Gmail - A plugin for the Trillian messenger program that lets you manage your accounts.
Desktop Applications
GCount - An application for Mac OSX that alerts you to new mail.
gDisk - An app for Mac OSX giving the ability to turn Gmail accounts into storage drives.
gFeeder - A small ticker for your Gmail that will let you know at a glance what’s coming in for you.
GetMail - Allows you to migrate your emails from Hotmail to your Gmail account.
Gmail Drive - Another tool for turning your Gmail account in to a virtual storage drive, this one works directly from inside Windows Explorer.
Gmail Loader - For Windows or Linux, aids you in loading your email to your Gmail account.
GMailFS - Turns your Gmail space into a virtual drive that your Windows Explorer can see.
GotMailG - A Mac widget to display the number of unread messages in your inbox.
POP3/IMAP server for GMAIL in JAVA - Allows you POP3 access via your favorite mail reader to your Gmail account, IMAP still in development.
Send To GMail - With one click, you can back up any file you want from your computer to your Gmail account.
Firefox Tools
Better Gmail - Combines some of the most popular Greasemonkey scripts in to one extension. Includes things such as skins, saved searches, keyboard macros, and more.
Delegate to Remember The Milk - Adds a button to Gmail and allows you make to-do lists.
Dragdropupload - Allows you to drag your files to the attachment box.
GCalQuickTab - Allows you to quickly change between Google Mail and Calendar with keyboard shortcuts.
Gmail Checker - Allows you to check your Gmail for new messages.
Gmail Manager - Allows you to not only manage multiple accounts, but know how much mail and spam they have.
Gmail Notifier - Get notifications of new emails right in your browser.
Gmail RTL - Adds direction buttons to your email.
Gmail S/Mime - Allows you to send and receive encrypted emails.
Gmail Skins - Change the look of your inbox, insert HTML tables, use emoticons and more.
Google Toolbar - Official Google release of a toolbar with Gmail features.
Gspace - Turns your Gmail account in to a virtual web drive that you can upload files to and store them.
gTalk Sidebar - Incorporates Google Talk into your sidebar.
GTDInBox - A Getting Things Done tool that integrates into Gmail, helps you get organized.
WebMail Notifier - Checks your Gmail account for unread emails; works with other email services also.
Greasemonkey Scripts
Clean Gmail Print - Removes the Gmail logo when you go to print out your email
Folders4Gmail - If you prefer the old style of sorting mail in folders over labels, this is the script for you.
Force HTTPS for GMail, GCal, and GDocs - Forces the corner links in the Google apps to change over to HTTPS.
gDate2Cal 0.1 - Turns dates in Gmail in to links to take you to that day in Google Calendar.
Gmail + Reader Integration - Lets you use Google Reader with your Gmail account.
GMail Attachment Icons - Shows you an icon that lets you know what type of file is attached to an email without opening it.
Gmail attachment reminder v2.4.1 - Reminds you to attach a file your email if it appears you haven’t.
Gmail Contact List - Adds a contact list near the “To” field in compose.
Gmail Conversation Preview - Right click on a conversation to get a preview of it in a bubble.
Gmail Date Search - adds a Search by Date button to Gmail’s search form
Gmail Delete Button - RED Color - Turns the delete button red so there is less chance of hitting it accidentally.
Gmail Emoticons! - Puts an emoticons button next to the “Check Spelling” button to allow you to enter numerous different smilies.
Gmail Encrypt - Allows you to encrypt outgoing emails and create encryption keys.
Gmail FavIcon Alerts - Turns the Gmail favicon in the address bar in to a new mail alert.
Gmail from address selector - Lets you change the reply-to email address depending on who you are sending to. (i.e. sending to someone like “@work.com”, you choose your work address as the from address)
Gmail Full Width - Removes the advertising block on the right so that your mails take up the full width.
Gmail Google Calendar sidebar - Adds your Google Calendar to your Gmail display.
Gmail Lite - Removes ads, the footer, stars, and chats.
Gmail Macros - Allows you to create more keyboard shortcuts to speed up your Gmail experience.
Gmail Multi-User Login - For those of you with more than one Gmail account, this will give you a drop down menu with all of your accounts listed.
Gmail Multiple Signatures, plus Float - Will change your signature based on what return address you enter.
Gmail - One Click Conversations - Allows you quick access to the most recent conversations with a contact via a one click button.
GMail Header, Navigation and Ads Switcher - Can choose to hide or show the header, navigation bar, and ads by clicking a button.
Gmail - Zip Attachments and Download - Allows you to download all the attachments of an email by merely clicking on the paper clip icon.
GmailTo -Opens mailto: commands from websites in Gmail compose.
Google Air Skin - Script to use Air Skin in Gmail, Google Calendar, on Google.com, and Google Reader.
Label Colors - Lets you choose the colors of various labels so you can tell them apart easier.
Plaxo4Gmail - Allows you to sync your Gmail with your Plaxo info.
Saved Searches - Allows you to save a Gmail search so that you can just click on the saved search to do it again.
Miscellaneous
GBooks - Allows you to turn a Gmail account in to a bookmarks server.
gExodus - Allows you to export your emails from another account to your Gmail account in mbox format.
Gmail icon generator - Allows you to create a small graphic of your Gmail address to place on websites so that you may display your address without spam bots reading it.
Gmail Music - Store MP3 files in your Gmail account and play them on any computer.
Gmail Todo - Turn your Gmail into a helpful “To Do” list.
PhpGmailDrive - Retrieves a list of attachments from a Gmail account and enables you to list them on a website or blog for others to download.
You’ve Got Gmail - A plugin for the Trillian messenger program that lets you manage your accounts.
10 GOOGLE SERVICES :
If you were to interview a broad cross-section of internet users and ask them about Google services, probably most of them would enthusiastically talk about Gmail or Google Reader. At the very least, they would mention Google’s superior search engine. But how many people do you think would discuss being able to set up customised RSS feeds in Google News? Or being able to download source code in Google Code? How many people would know that Google offers various possibilities for users to help improve their products?
Here are some Google services that need a lot more loving (cue Barry White music) :
(1) Google Labs
My favourite online playground (although the offerings at the moment are a little dull). This is where new Google products are first given the beta label and unleashed onto an unsuspecting world for testing and commenting. If you try something out in Google Labs, you are invited to email the Google team involved with comments / suggestions / complaints (on two occasions, I got a personal reply back from a member of the team, discussing my comments).
The way I see it, this is a good way to influence future Google products by getting involved in a product’s development. How many Google users use Google products but don’t bother to provide any creative input to make them better? Next time a Google product doesn’t go as planned, don’t complain on a forum - contact Google and offer constructive advice & criticism!
(2) Google Pack
If you know an internet newbie who has not so much knowledge of the internet and software products (like my mother), Google Pack provides an excellent software package to start with (although I personally wouldn’t choose Norton and Real Player). Check out full program list here.
(3) Google Translate
Translate text or even complete webpages into eleven languages (you can even translate from “simplified” Chinese to “traditional” Chinese). As with all online translators, this won’t give you a 100% accurate translation (online translators can’t grasp things like idioms and contexts) but if you want to buy those crates of AK-47 assault rifles from that online shop in North Korea, Google Translate will let you overcome that Korean language barrier.
(4) Google Co-Op
Allows you to customize Google search results with your own self-rolled search engines. You can also provide information from your website as a subscribed link or if you are a specialist in a particular subject area, you can label and categorize search information which other people can click on. Again, this is another way you can actively help in making search much better (otherwise known as user-generated input).
(5) Google Code
This one is for the computer geeks (of which I am a honorary member). Allows you to find and download source codes and developer API’s to make mashups for Google products.
(6) Google News
Google News has been around for a while and is old-hat to many. But how many of you knew that you could customise the page to only see the news you want to see? Or the fact you can set up customised RSS feeds for the news subjects that interest you? Never miss another news story about Paris Hilton ever again. You can also use the new news archive to find very old news stories, either scanned pages of publications or online sources. Some free, others not.
(7) Google Patent Search
If you’re in business and you’ve developed a hot new invention, don’t you want to check first to see if anybody got in there before you and filed a patent? Google Patent Search will show you the patent applications for pretty much everything so you can see right away if you are the sole inventor of the combined coat hanger and cigarette lighter.
(8) Google Blog Search
One of my personal favourites as it helps me to find current blogs on my favourite subjects (and swell my 200+ RSS reading list even further). Find blogs catering to various subjects. Want to know if anybody shares your overwhelming passion for navel lint by blogging about it? GBS will help you out.
(9) Google Alerts
Want to know if anybody has been talking about you online? Maybe somebody trashed your website by insulting it in a forum? Or a disgruntled customer to your online shop made disparaging remarks in their blog? By setting up a Google Alert (with pre-defined search terms), you will get an email with links anytime Google finds something matching your keywords. Britney Spears probably has one set up now with the keywords “Britney” and “MTV Music Awards”.
(10) Google Catalogs
Guys rejoice! (and women too). Want to buy some Victoria’s Secret lingerie? Or perhaps a new light-sabre is in order for you trusty Jedi Knights? Google now offers the chance to browse through scanned pages of catalogs and magazines such as GQ and Cosmopolitan to find products you might be looking for. No more raking in bins looking for catalogs of women in bikinis - Google now gives them to you online!
Here are some Google services that need a lot more loving (cue Barry White music) :
(1) Google Labs
My favourite online playground (although the offerings at the moment are a little dull). This is where new Google products are first given the beta label and unleashed onto an unsuspecting world for testing and commenting. If you try something out in Google Labs, you are invited to email the Google team involved with comments / suggestions / complaints (on two occasions, I got a personal reply back from a member of the team, discussing my comments).
The way I see it, this is a good way to influence future Google products by getting involved in a product’s development. How many Google users use Google products but don’t bother to provide any creative input to make them better? Next time a Google product doesn’t go as planned, don’t complain on a forum - contact Google and offer constructive advice & criticism!
(2) Google Pack
If you know an internet newbie who has not so much knowledge of the internet and software products (like my mother), Google Pack provides an excellent software package to start with (although I personally wouldn’t choose Norton and Real Player). Check out full program list here.
(3) Google Translate
Translate text or even complete webpages into eleven languages (you can even translate from “simplified” Chinese to “traditional” Chinese). As with all online translators, this won’t give you a 100% accurate translation (online translators can’t grasp things like idioms and contexts) but if you want to buy those crates of AK-47 assault rifles from that online shop in North Korea, Google Translate will let you overcome that Korean language barrier.
(4) Google Co-Op
Allows you to customize Google search results with your own self-rolled search engines. You can also provide information from your website as a subscribed link or if you are a specialist in a particular subject area, you can label and categorize search information which other people can click on. Again, this is another way you can actively help in making search much better (otherwise known as user-generated input).
(5) Google Code
This one is for the computer geeks (of which I am a honorary member). Allows you to find and download source codes and developer API’s to make mashups for Google products.
(6) Google News
Google News has been around for a while and is old-hat to many. But how many of you knew that you could customise the page to only see the news you want to see? Or the fact you can set up customised RSS feeds for the news subjects that interest you? Never miss another news story about Paris Hilton ever again. You can also use the new news archive to find very old news stories, either scanned pages of publications or online sources. Some free, others not.
(7) Google Patent Search
If you’re in business and you’ve developed a hot new invention, don’t you want to check first to see if anybody got in there before you and filed a patent? Google Patent Search will show you the patent applications for pretty much everything so you can see right away if you are the sole inventor of the combined coat hanger and cigarette lighter.
(8) Google Blog Search
One of my personal favourites as it helps me to find current blogs on my favourite subjects (and swell my 200+ RSS reading list even further). Find blogs catering to various subjects. Want to know if anybody shares your overwhelming passion for navel lint by blogging about it? GBS will help you out.
(9) Google Alerts
Want to know if anybody has been talking about you online? Maybe somebody trashed your website by insulting it in a forum? Or a disgruntled customer to your online shop made disparaging remarks in their blog? By setting up a Google Alert (with pre-defined search terms), you will get an email with links anytime Google finds something matching your keywords. Britney Spears probably has one set up now with the keywords “Britney” and “MTV Music Awards”.
(10) Google Catalogs
Guys rejoice! (and women too). Want to buy some Victoria’s Secret lingerie? Or perhaps a new light-sabre is in order for you trusty Jedi Knights? Google now offers the chance to browse through scanned pages of catalogs and magazines such as GQ and Cosmopolitan to find products you might be looking for. No more raking in bins looking for catalogs of women in bikinis - Google now gives them to you online!
Turn Any .exe File Into A Service
Turn Any .exe File Into A Service
This method has not been tested with Vista, though it is known to work with 2000/XP/2003 Server.
The following steps will allow you to turn almost any .exe file into a service. Please note that some .exe files will need command line parameters passed to run with functionality.
Log in with administrative privileges and then check that both INSTSRV.EXE and SRVANY.EXE are stored in a directory within the search path.
Take care where you put SRVANY.EXE because it must stay there for the service to run.
1. Open up an MS-DOS command prompt and navigate to where you saved the files.
2. Type the following command: INSTSRV [service name] SRVANY.EXE
where [service name] is the name of the service you are setting up. The service name can be anything you like, but you should make the name descriptive.
3. Remove service example:
INSTSRV [service name] REMOVE where [service name] is the service name.
4. Open up the Registry Editor (Click on the Start Button > Run, and type REGEDIT). Locate the following key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\[service name]
* From the Edit menu, click New > select Key, and name the new key Parameters
* Highlight the Parameters key
* From the Edit menu, select New > String Value, and name the new value Application
* From the Edit menu, select Modify, and type in the full path name and application name, including the drive letter and file extension
* Example: C:\Program Files\Network Monitor\netmon.exe
5. Close the Registry Editor.
6. You can now start the service from services.msc.
This method has not been tested with Vista, though it is known to work with 2000/XP/2003 Server.
The following steps will allow you to turn almost any .exe file into a service. Please note that some .exe files will need command line parameters passed to run with functionality.
Log in with administrative privileges and then check that both INSTSRV.EXE and SRVANY.EXE are stored in a directory within the search path.
Take care where you put SRVANY.EXE because it must stay there for the service to run.
1. Open up an MS-DOS command prompt and navigate to where you saved the files.
2. Type the following command: INSTSRV [service name] SRVANY.EXE
where [service name] is the name of the service you are setting up. The service name can be anything you like, but you should make the name descriptive.
3. Remove service example:
INSTSRV [service name] REMOVE where [service name] is the service name.
4. Open up the Registry Editor (Click on the Start Button > Run, and type REGEDIT). Locate the following key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\[service name]
* From the Edit menu, click New > select Key, and name the new key Parameters
* Highlight the Parameters key
* From the Edit menu, select New > String Value, and name the new value Application
* From the Edit menu, select Modify, and type in the full path name and application name, including the drive letter and file extension
* Example: C:\Program Files\Network Monitor\netmon.exe
5. Close the Registry Editor.
6. You can now start the service from services.msc.
Top 29 Most Wanted Firefox Plugins
Top 29 Most Wanted Firefox Plugins
Firefox plugins can make your browser based “work” quicker, easier and more convenient. Unlike extensions (which modify or add to existing functionality), plugins help your browser perform specific functions like viewing special graphic formats or playing multimedia files. Get tooled up with my top 10 20 29 list of Firefox plugins:
1. Firebug
Firebug integrates with Firefox to put a wealth of development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page.
2. Web Developer Toolbar
The Web Developer extension adds a menu and a toolbar with various web developer tools.
3. HTML Validator
HTML Validator is a Mozilla extension that adds HTML validation inside Firefox and Mozilla. The number of errors of a HTML page is seen on the form of an icon in the status bar when browsing.
4. All-in-One Sidebar
AiOS lets you open various windows as sidebar panels, and quickly switch between them. So it put an end to the window chaos! In addition to bookmarks and history it opens dialogues such as downloads, add-ons and more in the sidebar.
5. QuickFoxNotes
A multi-tab note taking extension which saves data on bookmarks so your notes will be synchronized if you have installed Xmarks or Mozilla weave without any new registration. This extension also supports most of the Notepad++ shortkeys.
6. Regular Expressions Tester
Regular Expressions Tester offers developers functions for testing their regular expressions.
The tool includes options like case sensitive, global and multiline search, color highlighting of found expressions and of special characters, a replacement function incl. backreferences, auto-closing of brackets, testing while writing and saving and managing of expressions.
7. Access Me
The current version of Access-Me is an Exploit-Me tool used to test some access vulnerabilities related to web applications. The tool works by sending several versions of the last page request. A request with the session removed will be sent. A request using the HTTP HEAD verb and a request using a made up SECCOM verb will be sent. A combination of session and HEAD/SECCOM will also be sent.
8. SQL Inject Me
SQL Injection vulnerabilites can cause a lot of damage to a web application. A malicious user can possibly view records, delete records, drop tables or gain access to your server. SQL Inject-Me is Firefox Extension used to test for SQL Injection vulnerabilities.
9. XSS Me
Cross-Site Scripting (XSS) is a common flaw found in todays web applications. XSS flaws can cause serious damage to a web application. Detecting XSS vulnerabilities early in the development process will help protect a web application from unnecessary flaws. XSS-Me is the Exploit-Me tool used to test for reflected XSS vulnerabilities.
10. UrlParams
Shows you the GET and POST parameters of the current website in the sidebar.
You can alter their values, add new parameters, switch get/post and more.
11. Context Search
Expands the context menu’s ‘Search for’ item into a list of installed search engines, allowing you to choose a specific search engine every time.
12. Codeburner
Provides searchable reference information and code examples for HTML and CSS. Also see Codeburner for Firebug.
13. Automatic Save Folder
This add-on will open the File Browser at the right location, using simple filters on the downloaded file.
The filters are based on filenames and hosted domain’s name.
14. FireShot
FireShot is a Firefox extension that creates screenshots of web pages (entirely or just visible part).Unlike other extensions, this plugin provides a set of editing and annotation tools, which let users quickly modify web captures and insert text annotations and graphical annotations. Such functionality will be especially useful for web designers, testers and content reviewers.
15. xmarks
Xmarks is the #1 bookmarking add-on. Install it on all your computers to keep your bookmarks and (optionally) passwords backed up and synchronized. Xmarks also helps you uncover the best of the web based on what millions of people are bookmarking.
16. GreaseMonkey
Allows you to customize the way a webpage displays using small bits of JavaScript.
17. Colorzilla
Advanced Eyedropper, ColorPicker, Page Zoomer and other colorful goodies.
18. Adblock Plus
Ever been annoyed by all those ads and banners on the internet that often take longer to download than everything else on the page? Install Adblock Plus now and get rid of them.
19. Image Zoom
Adds zoom functionality for images.
20. Locationbar²
More than a textbox:
* Puts emphasis on the domain to reduce spoofing risk
* Linkifies URL segments (press Ctrl, Meta, Shift or Alt)
* More URL formatting options configurable
21. Stylish
Restyle the web with Stylish, a user styles manager. Stylish lets you easily install themes and skins for Google, Facebook, YouTube, Orkut, and many, many other sites. You can even customize Firefox and other programs themselves.
22. ColorfulTabs
The most beautiful yet the simplest add-on that makes a strong colorful appeal. Colors every tab in a different color and makes them easy to distinguish while beautifying the overall appearance of the interface.
23. About Menu
Access the various about: pages in Mozilla and Firefox.
24. Firefox Accessibility Extension
Support web developers and people with disabilities in accessing and testing web resources for accessibility features.
25. Gmail Manager
The original Gmail notifier for multiple accounts. Allows you to receive new mail notifications along with viewing account details including unread messages, saved drafts, spam messages, labels with new mail, space used, and new mail snippets.
26. Coral IE Tab
An enhanced version of IE Tab which enables you to use the embedded IE engine within tabs of Mozilla Firefox. It supports Adblock Plus in IE, and can sync cookies between IE and Firefox.
27. NoScript
The best security you can get in a web browser!
Allow active content to run only from sites you trust, and protect yourself against XSS and Clickjacking attacks.
28. Operator
Operator leverages microformats and other semantic data that are already available on many web pages to provide new ways to interact with web services.
29. Scrapbook
ScrapBook is a Firefox extension, which helps you to save Web pages and easily manage collections. Key features are lightness, speed, accuracy and multi-language support.
Have I missed some that you can’t live without? Let me know and I’ll flagellate myself immediately.
Firefox plugins can make your browser based “work” quicker, easier and more convenient. Unlike extensions (which modify or add to existing functionality), plugins help your browser perform specific functions like viewing special graphic formats or playing multimedia files. Get tooled up with my top 10 20 29 list of Firefox plugins:
1. Firebug
Firebug integrates with Firefox to put a wealth of development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page.
2. Web Developer Toolbar
The Web Developer extension adds a menu and a toolbar with various web developer tools.
3. HTML Validator
HTML Validator is a Mozilla extension that adds HTML validation inside Firefox and Mozilla. The number of errors of a HTML page is seen on the form of an icon in the status bar when browsing.
4. All-in-One Sidebar
AiOS lets you open various windows as sidebar panels, and quickly switch between them. So it put an end to the window chaos! In addition to bookmarks and history it opens dialogues such as downloads, add-ons and more in the sidebar.
5. QuickFoxNotes
A multi-tab note taking extension which saves data on bookmarks so your notes will be synchronized if you have installed Xmarks or Mozilla weave without any new registration. This extension also supports most of the Notepad++ shortkeys.
6. Regular Expressions Tester
Regular Expressions Tester offers developers functions for testing their regular expressions.
The tool includes options like case sensitive, global and multiline search, color highlighting of found expressions and of special characters, a replacement function incl. backreferences, auto-closing of brackets, testing while writing and saving and managing of expressions.
7. Access Me
The current version of Access-Me is an Exploit-Me tool used to test some access vulnerabilities related to web applications. The tool works by sending several versions of the last page request. A request with the session removed will be sent. A request using the HTTP HEAD verb and a request using a made up SECCOM verb will be sent. A combination of session and HEAD/SECCOM will also be sent.
8. SQL Inject Me
SQL Injection vulnerabilites can cause a lot of damage to a web application. A malicious user can possibly view records, delete records, drop tables or gain access to your server. SQL Inject-Me is Firefox Extension used to test for SQL Injection vulnerabilities.
9. XSS Me
Cross-Site Scripting (XSS) is a common flaw found in todays web applications. XSS flaws can cause serious damage to a web application. Detecting XSS vulnerabilities early in the development process will help protect a web application from unnecessary flaws. XSS-Me is the Exploit-Me tool used to test for reflected XSS vulnerabilities.
10. UrlParams
Shows you the GET and POST parameters of the current website in the sidebar.
You can alter their values, add new parameters, switch get/post and more.
11. Context Search
Expands the context menu’s ‘Search for’ item into a list of installed search engines, allowing you to choose a specific search engine every time.
12. Codeburner
Provides searchable reference information and code examples for HTML and CSS. Also see Codeburner for Firebug.
13. Automatic Save Folder
This add-on will open the File Browser at the right location, using simple filters on the downloaded file.
The filters are based on filenames and hosted domain’s name.
14. FireShot
FireShot is a Firefox extension that creates screenshots of web pages (entirely or just visible part).Unlike other extensions, this plugin provides a set of editing and annotation tools, which let users quickly modify web captures and insert text annotations and graphical annotations. Such functionality will be especially useful for web designers, testers and content reviewers.
15. xmarks
Xmarks is the #1 bookmarking add-on. Install it on all your computers to keep your bookmarks and (optionally) passwords backed up and synchronized. Xmarks also helps you uncover the best of the web based on what millions of people are bookmarking.
16. GreaseMonkey
Allows you to customize the way a webpage displays using small bits of JavaScript.
17. Colorzilla
Advanced Eyedropper, ColorPicker, Page Zoomer and other colorful goodies.
18. Adblock Plus
Ever been annoyed by all those ads and banners on the internet that often take longer to download than everything else on the page? Install Adblock Plus now and get rid of them.
19. Image Zoom
Adds zoom functionality for images.
20. Locationbar²
More than a textbox:
* Puts emphasis on the domain to reduce spoofing risk
* Linkifies URL segments (press Ctrl, Meta, Shift or Alt)
* More URL formatting options configurable
21. Stylish
Restyle the web with Stylish, a user styles manager. Stylish lets you easily install themes and skins for Google, Facebook, YouTube, Orkut, and many, many other sites. You can even customize Firefox and other programs themselves.
22. ColorfulTabs
The most beautiful yet the simplest add-on that makes a strong colorful appeal. Colors every tab in a different color and makes them easy to distinguish while beautifying the overall appearance of the interface.
23. About Menu
Access the various about: pages in Mozilla and Firefox.
24. Firefox Accessibility Extension
Support web developers and people with disabilities in accessing and testing web resources for accessibility features.
25. Gmail Manager
The original Gmail notifier for multiple accounts. Allows you to receive new mail notifications along with viewing account details including unread messages, saved drafts, spam messages, labels with new mail, space used, and new mail snippets.
26. Coral IE Tab
An enhanced version of IE Tab which enables you to use the embedded IE engine within tabs of Mozilla Firefox. It supports Adblock Plus in IE, and can sync cookies between IE and Firefox.
27. NoScript
The best security you can get in a web browser!
Allow active content to run only from sites you trust, and protect yourself against XSS and Clickjacking attacks.
28. Operator
Operator leverages microformats and other semantic data that are already available on many web pages to provide new ways to interact with web services.
29. Scrapbook
ScrapBook is a Firefox extension, which helps you to save Web pages and easily manage collections. Key features are lightness, speed, accuracy and multi-language support.
Have I missed some that you can’t live without? Let me know and I’ll flagellate myself immediately.
CCNA INTERVIEW
Routers:
In 1992 main products of Cisco were Gateway Servers i.e.
AGS – Advanced Gateway Server
MGS – Mid-Range Gateway Server
IGS – Integrated Gateway Server
CGS – Compact Gateway Server
AGS+ - Advanced Gateway Server Plus
Routers are of two types, Modular and Non-Modular
1.Modular
Routers will not have fix interfaces, can be added or removed whenever required.
2.Non-Modular
Routers will have fix interfaces, cannot be added or removed, they are fixed.
SERIES MODELS
Each series will have different models Each models will have different features or functions
700 701,702,703,704,710 (supports ISDN Technology)
800 801,803,805,810 (supports ISDN+Leased line connection)
1000 1001,1003,1010,1011,1015
1100 1101,1102,1102,1115
1400 1401 - 1411
1600
1700
2500
2600
3600
4000
5000
7000
12000GSR
Gigabit Switched Routers
Products of Cisco:
Router
Switches
Bridges
Brouters
Repeaters
PIX – Packet Information Exchange
VPN Concentrator
AAA Server – Authentication, Authorizing, Accounting Server
IDS – Intrusion Detection System
Policy Manager
Fibre Optics
CRS – Carrier Routing System (provides 9.6TeraBytes per second)
CMTS or UBR – Cable Modem Terminating System
Network
Connection of two or more nodes over the physical media is called as Network.
Networking
Connection of two or more nodes over the physical media and sharing the resources is called as Networking.
Types of Network:
1.Peer-to-Peer Network
Peer meaning client, Operating system used as client are win95, 98,NT4.0 Workstation, Win2000 prof, ME, XP prof.
Workgroup is a small group of computers where no centralized administration and no security is provided.
2.Server based Networks
Server is the one that serves the resources to clients.
Client is the one that requests for the resources from server.
Non-dedicated Server is the system that works both as client and server.
Operating system used as server is WinNT 3.51, 4.0, Win2000server, Win2003server.
Domain
Logical group of computers where centralized administration and security is concerned.
Further types of network:
PAN – Personalized Area Network
LAN – Local Area Network
CAN – Campus Area Network or BAN – Branch Area Network (within 2km diameter using FDDI)
SAN – Storage Area Network
MAN – Metropolitan Area Network (takes support of PSTN)
WAN – Wide Area Network (takes support of X.25, Frame-relay, ATM, Internet, ISDN)
SoAN – Solaris Area Network (network using satellite)
WIRELESS
INTERNET
EXTRANET – Connection between different branches
INTRANET – Connection within the branches
LAN Requirements for Networking:
Server, Client, NIC, Cable (Media), Switch, Topology, Protocol, Services.
Media:
There are 2 types of media
1.Guided media (wired media) 2.UnGuided media (wireless media)
1.Guided media (wired media)
e.g. Co-axial cable, twisted pair cable, fibre optics cable
Co-axial cable
1.Maximum Distance 500mts
2.Low response
3.Less attenuation
4.Speed 10Mbps
5.Communication done is half duplex
6.Connection done using BNC – Bayonet Neil Concellmen Connector
7.Registered Guage Standard (RG)
RG 9,11,12 Thinnet Coaxial Cable
RG 58 Thicknet Coaxial Cable
RG 58/U, RG 58A/U Military Network
RG 59 Dish Network
RG 62 Arc Net
Thicknet also called as 10base5 where 10 – Bandwidth base – Baseband and 5 – 500mts
Thinnet also called as 10base2 where 10 – Bandwidth base – Baseband and 2 – 200mts
Twisted pair cable
1.Maximum Distance 100mts
2.Speed 10/100/1000Mbps
3.Communication done is half / full duplex
4.Connection done using RJ45 Connector
10baseT Supports 10Mbps
10baseTx Supports 10 or 100 Mbps
100baseT Supports 100Mbps
1000baseTx Supports 1Gbps
4 pairs of wires, orange – tip orange/white – tap.
All orange/white, green/white, blue/white, brown/white provides grounding to the orange, green, blue, brown wires.
Types of Twisted pair cable
1.Unshielded Twisted Pair Cable (UTP) 2.Shielded Twisted Pair Cable (STP)
Categories of Twisted pair cables
CAT1 Telephone Networks (4Mbps)
CAT2 Small Computer Networks, Telephone Networks (4Mbps)
CAT3 LAN – Ethernet (16Mbps)
CAT4 Token Ring Network (40Mbps)
CAT5 LAN – Fast Ethernet (100Mbps)
CAT5e & CAT6 LAN – Fast Ethernet (1Gbps / 1000Mbps)
Registered Jack (RJ Connectors)
RJ11 Telephones
RJ12 Telephone Network, Modems, Small Networks
RJ45 Local Area Network
Optical Fibre Cable
1.Maximum Distance 3 to 10 Kms
2.No EMI – Electro Magnetic Interference
3.Speed 100Mbps or Higher
4.Connectors used are ST – Straight Trip and SC – Subscriber Connectors
5.Two modes of communication Single mode (single beam) and Multiple mode (multiple beam)
2.UnGuided media (wireless media)
e.g. infrared, microwaves, radio waves
Infrared
1.Introduced in 1985
2.Point-to-Point communication (distance between 2 computers should not be more than 15mts)
3.Multipoint communication (distance between 2 computers should not be more than 30 mts)
4.Maximum Bandwidth 11Mbps
Microwaves
1.Electromagnetic Waves > 1Mhz
Radio Waves
1.Introduced in 1998 for computers
2.Electromagnetic Waves < 1Mhz
3.Maximum frequency available now is 2Ghz
Protocols
A set of rules for a particular type of communication.
Two types of Protocols
1.Connection Oriented 2.Connectionless Oriented
Connection Oriented
1.Follows the same path for data transfer
2.Acknowledgement
3.Reliable
4.e.g. TCP, SPX, AppleTalk datagram protocol
Connectionless Oriented
1.Follows the path where less traffic is found
2.No Acknowledgement
3.Non-Reliable
4.e.g. IP, IPX, UDP, AppleTalk protocol
Standards
Two types of Standards
1.Defacto Standard 2.Dejuire Standard
Defacto Standard
Standard widely used by all is called as Defacto Standard.
Dejuire Standard
Standard defined by an organization is called as Dejuire Standard.
Standard Organizations / Committees
IEEE – Institute of Electrical and Electronics Engineers
IANA – International Assigned Number Authority
ISO – International Standards Organization
ITU-T – International Telecommunication Union – Telecommunication Standardization Sector
EIA / TIA – Electronics Industry Association / Telecommunication Industry Association
ANSI – American National Standards Institute
Network Segmentation
Breaking up a larger network into a number of smaller ones is called as Network Segmentation and is accomplished using Routers, Switches and Bridges.
Causes of LAN Traffic congestion
1.Too many hosts in a broadcast domain
2.Broadcast storms
3.Multicasting
4.Low Bandwidth
5.Adding Hubs for connectivity to the network
6.A large amount of ARP and IPX Traffic.
Broadcast Domain
A group of devices receiving broadcast frames initiating from any device within the group.
Collision Domain
The network area in Ethernet over, which frames that have collided and damaged.
Broadcast Storms
An undesired event on the network caused by the simultaneous transmission of any number of broadcasts across the network.
Multicasting
Any communication between a single sender and multiple receivers.
ARP
Address Resolution Protocol, the protocol that traces IP addresses to MAC addresses.
IPX
Internetwork Packet Exchange, layer 3 protocol used in Novell Netware networks for transferring information from servers to workstations.
Router
It’s a layer 3 device that connects 2 different networks and routes packets of data from one network to another. It breaks up Broadcast domain as well as Collision Domain.
Advantages of Router
1.Router don’t forward Broadcasts by default.
2.Perform access control on the traffic that flows through the router i.e. Packet Filtering.
3.Network Address Translation.
4.Quality of Service for particular network traffic.
5.Can be used as a DHCP relay agent.
7.Connects different VLAN’s.
DCE-Data Communications Equipment
The DCE supplies the physical connection to the network, forwards traffic, and provides a clocking signal to synchronize data transmission between DTE and DCE devices.
DTE-Data Terminal Equipment
Any device located at the end user i.e. network interface serving as a destination or source or both. DTE includes devices such as Multiplexers, routers, protocol translators and computers.
Different Modes for configuring a router
1.User Mode- some basic commands like ping, telnet can be done. Prompt will be Router >
2.Execution or Privilege or Enable Mode- can view all configuration details, minimal commands like ping, telnet, and clock setting. Prompt will be Router #
3.Global Configuration Mode- where all configurations are done. Prompt will be Router(config)#
Sub Configuration Modes
1.Interface configuration mode, prompt will be Router(config-if)#
2.Router configuration mode, prompt will be Router(config-router)#
3.Line configuration mode, prompt will be Router(config-line)#
What is difference between Switch & Hub?
Switch:
Switches operate at Layer 2 Data Link Layer
Address Learning
Forward / Filter decision using MAC address
Loop Avoidance
Breakup collision domains
Switches create separate collision domains but a single broadcast domain
Hub:
Hub operates at Layer 1 Physical Layer
No Filtering
No Addressing
Hub creates single collision domain and single broadcast domain
Make forwarding to all the ports when signal is arrived
What is PING utility?
PING – Packet Internet Gopher
A utility that verifies connections to one or more remote hosts. The ping command uses the ICMP echo request and echo reply packets to determine whether a particular IP system on a network is functional. Ping is useful for diagnosing IP network or router failures.
What is a VLAN? What does VLAN provide?
VLAN – Virtual Local Area Network
Vlan is a logical grouping or segmenting a network connected to administratively defined ports on a switch, they provide Broadcast control, Security and Flexibility.
What is Subnetting? Why is it used?
Used in IP Networks to break up larger networks into smaller subnetworks. It is used to reduce network traffic, Optimized network performance, and simplify management i.e. to identify and isolate network problems.
Difference between the Communication and Transmission?
Communication is the process of sending and receiving data by means of a data cable that is connected externally.
Transmission means the transfer of data from the source to the destination.
What is RAID?
A method used to standardize and categorize fault-tolerant disk systems. RAID levels provide various mixes of performance, reliability, and cost. Some servers provide three of the RAID levels: Level 0 (striping), Level 1 (mirroring), and Level 5 (striping & parity).
What are 10Base2, 10Base5 and 10BaseT Ethernet LANs?
10Base2 an Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with a contiguous cable segment length of 200 meters (185mts). Known as Thinnet.
10Base5 an Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with a contiguous cable segment length of 500 meters. Known as Thicknet.
10BaseT an Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses two pairs of twisted-pair baseband signaling, with a contiguous cable segment length of 100 meters.
What are the two types of Transmission Technology available?
Point – to – Point and Broadcast
What is point-to-point protocol?
An industry standard suite of protocols for the use of point-to-point links to transport multiprotocol datagrams.
What are the possible ways of data exchange?
Simplex
Half-duplex
Full-duplex
What is difference between Baseband and Broadband Transmission?
In a baseband transmission, the entire bandwidth of the cable is consumed by a single signal.
In broadband transmission, signals are sent on multiple frequencies, allowing multiple signals to be sent simultaneously.
What is Protocol Data Unit?
The processes at each layer of the OSI model.
Layers PDU
Transport Segments
Network Packets/Datagrams
Data Link Frames
Physical Bits
What are major types of Networks and explain?
Peer-to-Peer Network
Computers can act as both servers sharing resources and as clients using the resources.
Server-based Network
Provide centralized control of network resources and rely on server computers to provide security and network administration
What is Passive Topology?
When the computers on the network simply listen and receive the signal, they are referred to as passive because they don’t amplify the signal in any way.
What is Mesh Network?
A network in which there are multiple network links between computers to provide multiple paths for data to travel.
How Gateway is different from Routers?
Gateway
A device connected to multiple physical TCP/IP networks capable of routing or delivering IP packets between them.
Router
It’s a layer 3 device that connects 2 different networks and routes packets of data from one network to another. It breaks up Broadcast domain as well as Collision Domain.
What is Brouter?
It’s a Hybrid device that combines the features of both bridges and routers.
What is Subnet?
A subdivision of an IP network.
What is Frame relay, in which layer it comes?
Frame relay is an industry standard, shared access, switched Data Link Layer encapsulation that services multiple virtual circuits and protocols between connected mechanism.
Frame relay is a packet-switched technology.
What is Terminal Emulation, in which layer it comes?
The use of software, installed on PC or LAN server, that allows the PC to function as if it were dumb terminal directly attached to a particular type of mainframe.
Telnet is also called as terminal emulation. It belongs to application layer.
What is Beaconing?
An FDDI frame or Token Ring frame that points to serious problem with the ring, such as a broken cable. The beacon frame carries the address of the station thought to be down.
What are NetBIOS and NetBEUI?
NetBIOS – Network Basic Input / Output System
An application-programming interface (API) that can be used by programs on a local area network (LAN). NetBIOS provides programs with a uniform set of commands for requesting the lower-level services required to manage names, conduct sessions, and send datagrams between nodes on a network.
NetBEUI – NetBIOS Extended User Interface
An improved version of the NetBIOS protocol, a network protocol native to Microsoft Networking. It is usually used in small, department-size local area networks (LANs) of 1 to 200 clients. It can use Token Ring source routing as its only method of routing.
What is Cladding?
A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.
What is Attenuation?
In communication weakening or loss of signal energy, typically caused by distance.
What is MAC address?
The address for a device as it is identified at the Media Access Control (MAC) layer in the network architecture. MAC address is usually stored in ROM on the network adapter card and is unique.
What is ICMP?
ICMP – Internet Control Message Protocol
It is a Network Layer Internet protocol, which can report errors and status information. We can use the ping command to send ICMP echo request messages and record the receipt of ICMP echo reply messages. With these messages, we can detect network or host communication failures and troubleshoot common TCP/IP connectivity problems.
What is difference between ARP and RARP?
ARP – Address Resolution Protocol
The protocol that traces IP addresses to MAC addresses.
RARP – Reverse Address Resolution Protocol
The protocol within the TCP/IP stack that maps MAC addresses to IP addresses.
What is the difference between TFTP and FTP application layer protocols?
TFTP – Trivial File Transfer Protocol
A stripped down version of FTP, easy to use and fast. TFTP has no Directory browsing, no Authentication and insecure it can only send and receive files.
FTP – File Transfer Protocol
The TCP/IP protocol used for transmitting files between network nodes. FTP allows access to both Directories and files, manipulating directories, typing file contents and copying files between hosts.
Explain 5-4-3 rule?
In a Ethernet network, between any two points on the network, there can be no more than five network segments or four repeaters, and of those five segments only three of segments can be populated.
What MAU?
MAU – Multistation Access Unit
What is the difference between routable and non- routable protocols?
Routable protocols can work with a router and can be used to build large networks. Non-Routable protocols are designed to work on small, local networks and cannot be used with a router.
What is logical link control?
One of two sublayers of the data link layer of OSI reference model, as defined by the IEEE 802 standard. This sublayer is responsible for error detection but not correction, flow control and framing.
What is Virtual Channel?
A logical circuit that is created by Virtual channel links. It carries data between two endpoints in a network.
The other name for Virtual Channel is Virtual Circuit.
What is Virtual Path?
Along any transmission path from a given source to a given destination, a group of virtual circuits can be grouped together into what is called path.
What is Packet Filter?
What is multicast routing?
Sending a message to a group multicast address is called multicasting, and its routing algorithm is called multicast routing.
What is IGP (Interior Gateway Protocol)?
Any protocol used by an internetwork to exchange routing data within an autonomous system. E.g. RIP, IGRP and OSPF.
What is EGP (Exterior Gateway Protocol)?
It is the protocol the routers in neighboring autonomous systems use to identify the set of networks that can be reached within or via each autonomous system.
What is Autonomous System?
A group of Networks under mutual administration that share the same routing methodology. Autonomous Systems are subdivided by Areas and must be assigned an individual 16-bit number by the IANA.
What is BGP (Border Gateway Protocol)?
It is a protocol used to advertise the set of networks that can be reached within an autonomous system. BGP enables this information to be shared with the autonomous system. This is newer than EGP (Exterior Gateway Protocol).
What is Gateway-to-Gateway protocol?
It is a protocol formerly used to exchange routing information between Internet core routers.
What is Kerberos?
An authentication mechanism used to verify user or host identity. Kerberos uses encryption to prevent intruders from discovering passwords and gaining unauthorized access to files.
What is OSPF (Open Shortest Path First)?
OSPF is the first Open Standard Link State Routing Protocol.
It’s a Classless Routing Protocol meaning when updates are sent they send both IP address and Subnet mask.
Administrative Distance is 110.
Metric used is Cost i.e. Cost= 108
---------------
Bandwidth
OSPF uses algorithm to build Routing Table called Dijisktra.
Sends only Incremental and Triggered updates. Route updates sent within the routers will be secured with the help of MD5 encrypted password.
Routing updates are sent as Multicast addresses i.e.
224.0.0.5 – SPF (all OSPF routers)
224.0.0.6 – Designated router and Backup Designated router
OSPF maintains 3 types of Routing table i.e. Routing Table (Dijisktra), Topology Table (SPF) and Neighborship Table.
In OSPF Routers can be connected in two methods i.e.
Point-to-Point Link
Point to Multipoint Link
In OSPF a single large Autonomous system is break into small areas. There should be atleast one area by name Area 0. It’s called as Backbone Area.
The Router that connects more than one Area is called as Area Border Routers.
The Router that connects to other Autonomous system is called as Autonomous System Boundary Router.
Router ID
If the priority is set 1 to all the routers then there is a tie in priority, in this case it will check if there is any loopback address is given to any router if not the router with highest value of IP address will be elected as Router ID.
This router will be then called as Designated Router and the router with less value of IP address after Designated Router will be called as Backup Designated Router.
If a Router has all interfaces existing in single area than that router is called as Internal Router.
Whenever a router send routing updates to DR and BDR it uses Destination address as 224.0.0.6 and when DR send updates to all the routers it uses Destination address as 224.0.0.5.
In OSPF routing updates are called as Link State Advertisements.
If an OSPF router wants to send updates to other OSPF router then it should carry 3 requirements i.e.
Hello Packets Received
It contains Area Id, Uptime, Password, Hello Interval, Dead Interval, Neighborship Table and Router Id.
Point-to-Point Link Point to Multipoint Link
Halo Interval – 10 Halo Interval – 30
Dead Interval – 40 Dead Interval – 120
Adjacency Built
If both router interfaces belongs to same Area, same Password then Hallo and Dead Intervals should be set same.
Neighborship Built
If both routers are adjacent to each other then Neighborship is built in Routers.
When one routerRA sends updates i.e. Link State Advertisements to other routerRB it will send that update to Topology Database of routerRB and will run an algorithm SPF on routerRB to create a new Topology Table. After that Dijisktra Algorithm is run to find the best path and that entry will be put in Routing Table.
The router when sends Hallo packets to other router a Neighborship Table is set on that Router.
What is SLIP (Serial Line Internet Protocol)?
An industry standard serial encapsulation for point-to-point connections that supports only a single routed protocol, TCP/IP.
What is RIP (Routing Information Protocol)?
Rip run on any Routers hence called as Open Standard Distance Vector Routing Protocol.
It’s a classful routing protocol meaning when updates are sent they send only IP address but not subnet mask.
Administrative Distance is 120.
Metric used is Hop counts (number of routers to cross to reach the destination).
Rip uses algorithm name Bellman Ford Algorithm to determine the best path selection.
Supports maximum 15 Hops.
Supports 6 paths if there is a tie in metric i.e. same metric.
RIP Timers
Route update timer – 30seconds
Route invalid timer – 180 seconds
Holddown timer – 180 seconds
Route flush timer – 240 seconds
What are the advantages and disadvantages of the three types of routing tables?
What is the HELLO protocol used for?
The HELLO protocol uses time instead of distance to determine optimal routing. It is an alternative to the Routing Information Protocol.
What is the difference between interior and exterior neighbor gateways?
Interior gateways connect LANs of one organization, whereas exterior gateways connect the organization to the outside world.
What protocol do DNS name servers use?
DNS uses UDP for communication between servers. It offers a connectionless datagram service that guarantees neither delivery nor correct sequencing of delivered packets (much like IP).
What is a DNS resource record?
A resource record is an entry in a name server's database. There are several types of resource records used, including name-to-address resolution information. Resource records are maintained as ASCII files.
BOOTP helps a diskless workstation boot. How does it get a message to the network looking for its ip address?
A protocol used primarily on TCP/IP networks to configure diskless workstations. BOOTP sends a UDP message with a subnetwork broadcast address and waits for a reply from a server that gives it the IP address.
What is anonymous FTP and why would you use it?
Anonymous FTP enables users to connect to a host without using a valid login and password. Usually, anonymous FTP uses a login called anonymous or guest, with the password usually requesting the user's ID for tracking purposes only. Anonymous FTP is used to enable a large number of users to access files.
How do Data Link layer addresses and Network addresses differ? Give a description of each.
Besides the names suggesting that addresses reside at different layers, other differences do exist. Data Link layer addresses are assigned by the manufacturer and identify the actual hardware device. A Network layer address is a logical address assigned by the network administrator to identify a device running a Network layer protocol, such as IP.
What are the differences or similarities, if any, between repeaters, hubs, and concentrators?
First, they are all Physical layer devices. Repeaters regenerate and amplify the signal traveling on the wire to extend the normal distance limitation of the signal. A repeater can connect two network segments. A hub and a concentrator are the same thing, with hub being the more common term used today. Hubs are repeaters with 8–24 ports. When one machine attached to the hub sends anything over the network, all the devices attached to the hub receive that signal.
Describe, in general terms, the reasons for implementing LAN segmentation.
It confines user traffic to a segment and addresses and solves distance limitation problems. Segmentation also cuts down on the traffic generated by broadcasts and multicasts, and thereby increases performance. Because of the reduction of the size of the segment, collisions and overall traffic also are reduced.
Which of the three switching methods is fastest, and why?
Cut-Through switching is the fastest method because the switches read only the first six bytes of the frame before forwarding it.
What services do bridges and switches provide?
Bridges and switches can determine whether a frame is destined for the local network segment or needs to be forwarded to another network segment based on the destination MAC address.
What are some of the advantages to using bridging and switching instead of routing?
Increased overhead and latency
Reduced overhead and latency
Broadcast propagation
Lower equipment costs
Answer A is incorrect because it is a negative aspect of routing as compared to switching. Answer B is correct because bridges and switches look only at Data Link layer information, whereas routers must process all the logical address information in the route tables. Answer C is incorrect because switches do not have this effect. Answer D is incorrect because switches are now very sophisticated and can cost as much as routers.
What would be the best network segmentation device if you wanted to connect two dissimilar networks, such as Ethernet and Token-Ring?
A bridge or a switch
A concentrator or a hub
A router
A gateway
Answer A is incorrect because bridges and switches can’t perform protocol translation. Answer B is incorrect because neither a concentrator nor a hub can segment a network. Answer C is correct because routers can provide translation between dissimilar protocols, among other things. Answer D is incorrect because a gateway functions as a translator, not a segmentation device.
Why is overhead or latency associated with routers? (Choose all that apply.)
Routers must work at layer 3, which is inherently slower.
Routers must examine the frame header before passing it.
Routers must hold a frame for a given period of time for security purposes.
Routers must translate the signal, but then the signal can cut through directly.
Answer A is correct because resolving those addresses is more time consuming. Answer B is correct because the router must examine and consider the frame header detail before passing it, which slows processing. Answers C and D are incorrect because they are simply not accurate.
Which of the following represents Physical layer devices?
Repeaters, bridges, and concentrators
Repeaters, hubs, and concentrators
Repeaters, routers, and bridges
Repeaters, routers, and switches
Answer B is correct because repeaters, hubs, and concentrators comprise the only combination that resides at the Physical layer. Answers A, C, and D are combinations of devices that reside at different layers.
How do routers make routing decisions?
They build tables and make their decisions based on those tables.
They perform lookups and make their decisions dynamically with discovery.
They use hello packets to discover routes on the fly.
They query NetBIOS cache for the appropriate paths.
Answer A is correct because routing decisions are made based on the contents of routing tables. Answer B is incorrect because routers are incapable of making decisions without tables already in place. Answer C is incorrect because hello packets are used to calculate routes when new routers are added to a network. Answer D is incorrect because it is simply inaccurate.
Choose the devices that are used for Data Link layer segmentation.
Concentrators and switches
Routers and bridges
Bridges and switches
Bridges and hubs
Answer A is incorrect because concentrators reside at the Physical layer and switches at the Data Link layer. Answer B is incorrect because routers are level 3 devices and bridges are level 2 devices. Answer C is correct because bridges and switches reside at the Data Link layer. Answer D is incorrect because bridges reside at the Data Link layer and hubs at the Physical layer.
What is an advantage of having a VLAN (Virtual LAN)?
Traffic control between VLANs is processor intensive.
Broadcasts of multicast traffic are contained within one VLAN.
They’re more flexible because they enable device assignment only on a port-by-port basis.
With VLANs, users are not inherently isolated by group.
Answer A is incorrect because there is nothing more or less processor intensive about VLANs. Answer B is incorrect because there is no such thing as a broadcast of multicast traffic; the words broadcast and multicast are mutually exclusive. Answer C is correct because VLANs extend the flexibility of LANs by enabling the port-by-port isolation of users and assignment to distinct VLANs if desired. Answer D is incorrect because VLANs by their definition segment workgroups.
Which two characteristics describe Store and Forward switching?
The entire frame is copied into the buffer.
The frame is forwarded based on the first six bytes.
It provides higher throughput.
It provides error checking.
Answers A and D are correct because Store and Forward switching copies the entire frame into the buffer before forwarding, which also provides for error checking. Answers B and C are incorrect because they describe Cut-Through.
Which two characteristics describe Cut-Through switching?
The entire frame is copied into the buffer.
The frame is forwarded based on the first six bytes.
It provides higher throughput.
It provides error checking.
Answers B and C are correct because Cut-Through switching provides forwarding based on what is contained in the first six bytes of the frame, which provides higher throughput. Answers A and D are incorrect because they describe Store and Forward switching.
Name the Cisco proprietary protocol that allows VLANs to be managed within domains.
VTP (VLAN Trunking Protocol) allows multiple VLANs to be managed within a single VTP domain.
Name the three VTP modes in which a switch can operate.
VTP switches operate in one of three modes: server, client, or transparent.
Name the Cisco proprietary protocol used on Fast Ethernet VLAN trunk links.
ISL (Inter-Switch Link) protocol is used to encapsulate VLAN traffic over Fast Ethernet trunk links.
At what layer of the OSI model do VLANs operate?
VLANs operate at layer 2 of the OSI model.
To allow Inter-VLAN communication, what does your router require?
You need a router that has some kind of viable trunking connection, such as Fast Ethernet (ISL), and must be configured with subinterfaces.
Choose one method of decreasing broadcasts across a switched network.
Set up an Intra-LAN.
Set up a workgroup banded by a server cluster.
Set up a VLAN to isolate traffic.
Set up a firewall to isolate traffic.
Answers A and B are incorrect because they are simply false. Answer C is correct because each VLAN becomes its own broadcast domain. Answer D is incorrect because a firewall is meant to shelter internal networks from intrusion from the outside.
Choose two benefits of VLAN implementation.
VLANs incorporate only one router per routed subnet.
VLANs control broadcasts.
VLANs amplify broadcasts.
VLANs ease security restrictions.
VLANs provide increased network security.
Answer A is incorrect because routers are not at all necessary for a VLAN to operate. Answers B and E are correct because VLAN implementation controls broadcasts and provides isolation, therefore security. Answers C and D are simply incorrect.
What is the purpose of a trunking protocol?
To connect the backbone of a primary VLAN to the backbone of a secondary VLAN
For one switch fabric to be integrated with another switch fabric
For a VLAN on one switch to be linked to a VLAN on another switch
To enable multiple trunking protocols to communicate
Answers A is incorrect because it uses wrong terminology. Answer B is incorrect because switch fabric is a hardware-related component of a switch and belongs to one switch only. Answer C is correct because trunking protocols allow management of VLANs with similar or dissimilar trunking protocols. Answer D is incorrect because a trunking protocol does not enable multiple trunking protocols to communicate.
Choose the encapsulation protocol used on Fast Ethernet links.
Cisco Switch Link
Dedicated Switch Link
Inter-Switch Link
VLAN Switch Link
Answer C is correct because Inter-Switch Link protocol is the encapsulation protocol used on Fast Ethernet links. Answers A, B, and D is incorrect because no such links exist.
At which layer of the OSI model does ISL function?
Data Link layer
Network layer
Physical layer
LLC Data Link sublayer
Answer A is correct because ISL functions at the Data Link layer of the OSI model. Answers B and C are incorrect because ISL does not function at those layers of the OSI model. Answer D is incorrect because the specific sublayer does not have any distinction in this context.
Which method is used by VTP to convey VLAN configuration information within its management domain?
Through directed broadcasts
Through LSA’s local service advertisements
Through multicast advertisements
Through port flooding
Answer C is correct because multicast advertisement convey configuration information to all connected switches in the same management domain. Answers A, B, and D is incorrect because they do not convey information within management domains.
In ATM LANE, what factor determines the type of trunking protocol used?
The link type
The encapsulation mode
The density of VLANs
The ATM LANE Module type
Answer A is correct because the link type determines the type of trunking protocol used. Answers B and C are incorrect because they are simply false. Answer D is incorrect because the ATM LANE Module is a hardware card and does not affect trunking protocols.
What is VTP designed to do?
It enables an administrator to manage VLANs across multiple trunk links.
It enables an administrator to manage VLANs across dissimilar trunking protocols.
It enables an administrator to merge the management duties of more than two trunk links together.
It is used to synchronize VTP advertisements across multiple trunk links.
Answer A is incorrect because trunk links do not address the aspect of communication. Answer B is correct because VTP is designed to enable an administrator to manage VLANs running dissimilar trunking protocols. Answer C is incorrect because a trunk link does not necessary entail management duties on its own. Answer D is incorrect because it is simply false.
What is a limitation of Intra-VLAN traffic?
Communication is limited to VLANs directly connected to a router.
Communication is limited to VLANs off the same switch backplane.
Communication is limited to devices within the same VLAN.
Communication is limited to devices between VLANs.
Answer A is incorrect because VLANs are connected for Inter-VLAN communication. Answer B is incorrect because the backplane is where traffic is actually switched, and it is a hardware component. Answer C is correct because that is the very definition of Intra-VLAN traffic. Answer D is incorrect because VLANs cannot talk to each other without a router.
VTP (Virtual Trunking Protocol) exists at which layer and for what purpose?
Layer 2, to maintain VLAN configuration consistency
Layer 2, to maintain trunking protocol synchronization
Layer 2, to maintain domain synchronization
Layer 3, to maintain access lists
Answer A is correct because VTP operates at layer 2 and maintains VLAN configuration consistency. Although the OSI layer is correct, answers B and C are incorrect because the second portion of the answers is incorrect. Answer D is incorrect because VTP and switching do not operate at layer 3 and access lists are maintained on routers.
What two basic steps are necessary to create access list filters?
The first step is to build the list at global configuration mode using the access-list command followed by an access list number signifying the type. The second step is to apply the list to an interface by using the [protocol type] access-group command followed by the access list number and parameters.
Identify the appropriate access list range values used to create access lists.
IP standard access list = 1–99
IP extended access list = 100–199
IPX standard access list = 800–899
IPX extended access list = 900–999
IPX SAP filter = 1000–1099
What is the purpose of a wildcard mask?
To enable an administrator to apply an access list rule to a group of hosts or subnets by masking off bits within an IP address, making the bit positions within the mask variable.
Name the access list keywords.
any = 0.0.0.0 255.255.255.255
host = specific IP address of an end host (192.16.10.2 0.0.0.0)
How does the direction in which an access list is applied affect datagram processing?
Access lists applied to an interface in an inbound direction determine whether a datagram received on an interface will be forwarded or blocked. Access lists applied to an interface in an outbound direction determine whether a datagram already received will be forwarded out that interface.
What is the access list number range used to identify an IP standard access list?
0–100
1–100
1–99
1–10
101–199
Answer C is correct because the correct value range to identify an IP standard access list is 1–99. Answers A, B, D, and E are incorrect because they are not ranges used to identify an IP standard access list.
Which of the following represents the default wildcard mask value?
0.0.0.0
255.255.255.255
0.0.255.255
255.255.255.0
Answer A is correct because, if unspecified, the default mask used is 0.0.0.0. Answers B and C are incorrect because neither are the default mask. Answer D is incorrect because it is a regular mask, which is not used for wildcard masking.
Write the command that would apply access list 100 to interface E0 in an outbound direction. (Assume you are already at interface configuration mode of the Ethernet interface.)
IP access-group 100 out
IP access-list 100 out
IP access-group 100 in
IP access-group E0 out
Answer A is correct because IP access-group 100 out is the command that would apply access list 100 to interface E0 in an outbound direction. Answers B, C, and D are simply incorrect.
Which of the following commands creates a standard IP extended access list that enables ping echo requests to be sent from any host on network 166.10.0.0 to network 155.10.0.0?
Access-list 12 permit IP 166.10.0.0.0.0.255.255 host 155.10.0.0
Access-list 120 permit ICMP 166.10.0.0 0.0.255.155 155.10.0.0 0.0.0.255 eq echo
Access-list 120 permit 166.10.0.0.0.0.255.255 host 155.10.0.0
Access-list 120 permit ICMP 166.10.0.0 0.0.255.255 155.10.0.0 0.0.255.255 eq echo
Answer A is incorrect because the access list number is not an extended list number. Also, the protocol type is IP not ICMP, and the destination is specifying the host keyword but using a subnet value instead, which is invalid. Answer B is incorrect because it uses an incorrect inverse mask for the destination network. Answer C is incorrect because it does not specify the protocol after the permit statement and also is using the host keyword with the destination network. Answer D is correct because it uses a valid access list number and syntax to forward ICMP echo requests.
Write the command to view all access lists created on your router regardless of protocol.
show access-lists
show ip access-lists
show ipx interfaces
show ipx servers
Answer A is correct because show access-lists enables you to view all access lists created on your router regardless of protocol. Answers B, C, and D are incorrect because these commands do not enable you to perform that specific function.
Which of the following best describes the function of the following access list line?
Access-list 87 permit 145.19.2.1 0.0.0.0 155.6.0.0 0.0.255.255
Any host on subnet 155.6.0.0 can access host 145.19.2.1.
It is an IPX standard access list allowing host 145.19.2.1 to access any host on subnet 155.6.0.0.
It is an extended IP access list allowing hosts on network 145.19.0.0 to access hosts on network 145.19.0.0, which can access host 155.6.255.255.
It is an IP standard access list enabling host 145.19.2.1 to access any host on subnet 155.6.0.0.
Answers A and C are incorrect because they do not state the actions of this access list correctly. Answer B is incorrect because this is not an IPX standard list. Answer D is correct because it correctly describes the access list behavior.
Which of the following commands applies IPX SAP filter 1010 to an interface in the outbound direction?
IPX access-group 1010 out
IPX output-sap-filter 1010
IPX output sap-filter 1010
IPX-sap-filter 1010 out
Answer A is incorrect because it is the syntax used to define a standard or extended list. Answer B is correct because it uses the correct syntax. Answer C is incorrect because it is missing the hyphen between the output and sap commands. Answer D is incorrect because it is a completely invalid command.
Which command can you use to display a list of access list filters configured on your router for IP only?
show IP access-lists
show access-lists
show IPX interfaces
show IPX servers
Answer A is correct because show IP access-lists enables you to display a list of access list filters configured on your router for IP only. Answers B, C, and D are incorrect because these commands do not enable that specific function.
Write the command to bind IPX extended access list 901 to interface serial 0 on an inbound direction.
IPX access-group 901 in
IPX access-group 901 S0 out
IPX access-group 910 in
IPX access-group 901 out
Answer A is correct because IPX access-group 901 in is the command that will bind the IPX extended access list 901 to interface serial 0 on an inbound direction. Answers B, C, and D are incorrect because they are simply false.
Which two of the following commands will enable Telnet traffic from all hosts on network 166.10.0.0 to be forwarded to the Telnet server 137.2.10.1?
Access-list 110 permit TCP 166.10.0.0 0.0.255.255 host 137.2.10.1 eq Telnet
Access-list 99 permit TCP 166.10.0.0 0.0.255.255 137.2.10.1 0.0.0.0. eq 23
Access-list 110 permit TCP 166.10.0.0 0.0.255.255 137.2.10.1 0.0.0.0 eq 23
Access-list 110 permit IP 166.10.0.0 0.0.255.255 137.2.10.1 0.0.0.0. eq 23
Answers A and C are correct. The only difference between the two is that Answer A uses the host keyword and the Telnet keyword instead of a port number. Answer B is incorrect because the access list number is 99, which is used for standard lists. Answer D is incorrect because it uses IP instead of TCP after the permit statement.
In 1992 main products of Cisco were Gateway Servers i.e.
AGS – Advanced Gateway Server
MGS – Mid-Range Gateway Server
IGS – Integrated Gateway Server
CGS – Compact Gateway Server
AGS+ - Advanced Gateway Server Plus
Routers are of two types, Modular and Non-Modular
1.Modular
Routers will not have fix interfaces, can be added or removed whenever required.
2.Non-Modular
Routers will have fix interfaces, cannot be added or removed, they are fixed.
SERIES MODELS
Each series will have different models Each models will have different features or functions
700 701,702,703,704,710 (supports ISDN Technology)
800 801,803,805,810 (supports ISDN+Leased line connection)
1000 1001,1003,1010,1011,1015
1100 1101,1102,1102,1115
1400 1401 - 1411
1600
1700
2500
2600
3600
4000
5000
7000
12000GSR
Gigabit Switched Routers
Products of Cisco:
Router
Switches
Bridges
Brouters
Repeaters
PIX – Packet Information Exchange
VPN Concentrator
AAA Server – Authentication, Authorizing, Accounting Server
IDS – Intrusion Detection System
Policy Manager
Fibre Optics
CRS – Carrier Routing System (provides 9.6TeraBytes per second)
CMTS or UBR – Cable Modem Terminating System
Network
Connection of two or more nodes over the physical media is called as Network.
Networking
Connection of two or more nodes over the physical media and sharing the resources is called as Networking.
Types of Network:
1.Peer-to-Peer Network
Peer meaning client, Operating system used as client are win95, 98,NT4.0 Workstation, Win2000 prof, ME, XP prof.
Workgroup is a small group of computers where no centralized administration and no security is provided.
2.Server based Networks
Server is the one that serves the resources to clients.
Client is the one that requests for the resources from server.
Non-dedicated Server is the system that works both as client and server.
Operating system used as server is WinNT 3.51, 4.0, Win2000server, Win2003server.
Domain
Logical group of computers where centralized administration and security is concerned.
Further types of network:
PAN – Personalized Area Network
LAN – Local Area Network
CAN – Campus Area Network or BAN – Branch Area Network (within 2km diameter using FDDI)
SAN – Storage Area Network
MAN – Metropolitan Area Network (takes support of PSTN)
WAN – Wide Area Network (takes support of X.25, Frame-relay, ATM, Internet, ISDN)
SoAN – Solaris Area Network (network using satellite)
WIRELESS
INTERNET
EXTRANET – Connection between different branches
INTRANET – Connection within the branches
LAN Requirements for Networking:
Server, Client, NIC, Cable (Media), Switch, Topology, Protocol, Services.
Media:
There are 2 types of media
1.Guided media (wired media) 2.UnGuided media (wireless media)
1.Guided media (wired media)
e.g. Co-axial cable, twisted pair cable, fibre optics cable
Co-axial cable
1.Maximum Distance 500mts
2.Low response
3.Less attenuation
4.Speed 10Mbps
5.Communication done is half duplex
6.Connection done using BNC – Bayonet Neil Concellmen Connector
7.Registered Guage Standard (RG)
RG 9,11,12 Thinnet Coaxial Cable
RG 58 Thicknet Coaxial Cable
RG 58/U, RG 58A/U Military Network
RG 59 Dish Network
RG 62 Arc Net
Thicknet also called as 10base5 where 10 – Bandwidth base – Baseband and 5 – 500mts
Thinnet also called as 10base2 where 10 – Bandwidth base – Baseband and 2 – 200mts
Twisted pair cable
1.Maximum Distance 100mts
2.Speed 10/100/1000Mbps
3.Communication done is half / full duplex
4.Connection done using RJ45 Connector
10baseT Supports 10Mbps
10baseTx Supports 10 or 100 Mbps
100baseT Supports 100Mbps
1000baseTx Supports 1Gbps
4 pairs of wires, orange – tip orange/white – tap.
All orange/white, green/white, blue/white, brown/white provides grounding to the orange, green, blue, brown wires.
Types of Twisted pair cable
1.Unshielded Twisted Pair Cable (UTP) 2.Shielded Twisted Pair Cable (STP)
Categories of Twisted pair cables
CAT1 Telephone Networks (4Mbps)
CAT2 Small Computer Networks, Telephone Networks (4Mbps)
CAT3 LAN – Ethernet (16Mbps)
CAT4 Token Ring Network (40Mbps)
CAT5 LAN – Fast Ethernet (100Mbps)
CAT5e & CAT6 LAN – Fast Ethernet (1Gbps / 1000Mbps)
Registered Jack (RJ Connectors)
RJ11 Telephones
RJ12 Telephone Network, Modems, Small Networks
RJ45 Local Area Network
Optical Fibre Cable
1.Maximum Distance 3 to 10 Kms
2.No EMI – Electro Magnetic Interference
3.Speed 100Mbps or Higher
4.Connectors used are ST – Straight Trip and SC – Subscriber Connectors
5.Two modes of communication Single mode (single beam) and Multiple mode (multiple beam)
2.UnGuided media (wireless media)
e.g. infrared, microwaves, radio waves
Infrared
1.Introduced in 1985
2.Point-to-Point communication (distance between 2 computers should not be more than 15mts)
3.Multipoint communication (distance between 2 computers should not be more than 30 mts)
4.Maximum Bandwidth 11Mbps
Microwaves
1.Electromagnetic Waves > 1Mhz
Radio Waves
1.Introduced in 1998 for computers
2.Electromagnetic Waves < 1Mhz
3.Maximum frequency available now is 2Ghz
Protocols
A set of rules for a particular type of communication.
Two types of Protocols
1.Connection Oriented 2.Connectionless Oriented
Connection Oriented
1.Follows the same path for data transfer
2.Acknowledgement
3.Reliable
4.e.g. TCP, SPX, AppleTalk datagram protocol
Connectionless Oriented
1.Follows the path where less traffic is found
2.No Acknowledgement
3.Non-Reliable
4.e.g. IP, IPX, UDP, AppleTalk protocol
Standards
Two types of Standards
1.Defacto Standard 2.Dejuire Standard
Defacto Standard
Standard widely used by all is called as Defacto Standard.
Dejuire Standard
Standard defined by an organization is called as Dejuire Standard.
Standard Organizations / Committees
IEEE – Institute of Electrical and Electronics Engineers
IANA – International Assigned Number Authority
ISO – International Standards Organization
ITU-T – International Telecommunication Union – Telecommunication Standardization Sector
EIA / TIA – Electronics Industry Association / Telecommunication Industry Association
ANSI – American National Standards Institute
Network Segmentation
Breaking up a larger network into a number of smaller ones is called as Network Segmentation and is accomplished using Routers, Switches and Bridges.
Causes of LAN Traffic congestion
1.Too many hosts in a broadcast domain
2.Broadcast storms
3.Multicasting
4.Low Bandwidth
5.Adding Hubs for connectivity to the network
6.A large amount of ARP and IPX Traffic.
Broadcast Domain
A group of devices receiving broadcast frames initiating from any device within the group.
Collision Domain
The network area in Ethernet over, which frames that have collided and damaged.
Broadcast Storms
An undesired event on the network caused by the simultaneous transmission of any number of broadcasts across the network.
Multicasting
Any communication between a single sender and multiple receivers.
ARP
Address Resolution Protocol, the protocol that traces IP addresses to MAC addresses.
IPX
Internetwork Packet Exchange, layer 3 protocol used in Novell Netware networks for transferring information from servers to workstations.
Router
It’s a layer 3 device that connects 2 different networks and routes packets of data from one network to another. It breaks up Broadcast domain as well as Collision Domain.
Advantages of Router
1.Router don’t forward Broadcasts by default.
2.Perform access control on the traffic that flows through the router i.e. Packet Filtering.
3.Network Address Translation.
4.Quality of Service for particular network traffic.
5.Can be used as a DHCP relay agent.
7.Connects different VLAN’s.
DCE-Data Communications Equipment
The DCE supplies the physical connection to the network, forwards traffic, and provides a clocking signal to synchronize data transmission between DTE and DCE devices.
DTE-Data Terminal Equipment
Any device located at the end user i.e. network interface serving as a destination or source or both. DTE includes devices such as Multiplexers, routers, protocol translators and computers.
Different Modes for configuring a router
1.User Mode- some basic commands like ping, telnet can be done. Prompt will be Router >
2.Execution or Privilege or Enable Mode- can view all configuration details, minimal commands like ping, telnet, and clock setting. Prompt will be Router #
3.Global Configuration Mode- where all configurations are done. Prompt will be Router(config)#
Sub Configuration Modes
1.Interface configuration mode, prompt will be Router(config-if)#
2.Router configuration mode, prompt will be Router(config-router)#
3.Line configuration mode, prompt will be Router(config-line)#
What is difference between Switch & Hub?
Switch:
Switches operate at Layer 2 Data Link Layer
Address Learning
Forward / Filter decision using MAC address
Loop Avoidance
Breakup collision domains
Switches create separate collision domains but a single broadcast domain
Hub:
Hub operates at Layer 1 Physical Layer
No Filtering
No Addressing
Hub creates single collision domain and single broadcast domain
Make forwarding to all the ports when signal is arrived
What is PING utility?
PING – Packet Internet Gopher
A utility that verifies connections to one or more remote hosts. The ping command uses the ICMP echo request and echo reply packets to determine whether a particular IP system on a network is functional. Ping is useful for diagnosing IP network or router failures.
What is a VLAN? What does VLAN provide?
VLAN – Virtual Local Area Network
Vlan is a logical grouping or segmenting a network connected to administratively defined ports on a switch, they provide Broadcast control, Security and Flexibility.
What is Subnetting? Why is it used?
Used in IP Networks to break up larger networks into smaller subnetworks. It is used to reduce network traffic, Optimized network performance, and simplify management i.e. to identify and isolate network problems.
Difference between the Communication and Transmission?
Communication is the process of sending and receiving data by means of a data cable that is connected externally.
Transmission means the transfer of data from the source to the destination.
What is RAID?
A method used to standardize and categorize fault-tolerant disk systems. RAID levels provide various mixes of performance, reliability, and cost. Some servers provide three of the RAID levels: Level 0 (striping), Level 1 (mirroring), and Level 5 (striping & parity).
What are 10Base2, 10Base5 and 10BaseT Ethernet LANs?
10Base2 an Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with a contiguous cable segment length of 200 meters (185mts). Known as Thinnet.
10Base5 an Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with a contiguous cable segment length of 500 meters. Known as Thicknet.
10BaseT an Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses two pairs of twisted-pair baseband signaling, with a contiguous cable segment length of 100 meters.
What are the two types of Transmission Technology available?
Point – to – Point and Broadcast
What is point-to-point protocol?
An industry standard suite of protocols for the use of point-to-point links to transport multiprotocol datagrams.
What are the possible ways of data exchange?
Simplex
Half-duplex
Full-duplex
What is difference between Baseband and Broadband Transmission?
In a baseband transmission, the entire bandwidth of the cable is consumed by a single signal.
In broadband transmission, signals are sent on multiple frequencies, allowing multiple signals to be sent simultaneously.
What is Protocol Data Unit?
The processes at each layer of the OSI model.
Layers PDU
Transport Segments
Network Packets/Datagrams
Data Link Frames
Physical Bits
What are major types of Networks and explain?
Peer-to-Peer Network
Computers can act as both servers sharing resources and as clients using the resources.
Server-based Network
Provide centralized control of network resources and rely on server computers to provide security and network administration
What is Passive Topology?
When the computers on the network simply listen and receive the signal, they are referred to as passive because they don’t amplify the signal in any way.
What is Mesh Network?
A network in which there are multiple network links between computers to provide multiple paths for data to travel.
How Gateway is different from Routers?
Gateway
A device connected to multiple physical TCP/IP networks capable of routing or delivering IP packets between them.
Router
It’s a layer 3 device that connects 2 different networks and routes packets of data from one network to another. It breaks up Broadcast domain as well as Collision Domain.
What is Brouter?
It’s a Hybrid device that combines the features of both bridges and routers.
What is Subnet?
A subdivision of an IP network.
What is Frame relay, in which layer it comes?
Frame relay is an industry standard, shared access, switched Data Link Layer encapsulation that services multiple virtual circuits and protocols between connected mechanism.
Frame relay is a packet-switched technology.
What is Terminal Emulation, in which layer it comes?
The use of software, installed on PC or LAN server, that allows the PC to function as if it were dumb terminal directly attached to a particular type of mainframe.
Telnet is also called as terminal emulation. It belongs to application layer.
What is Beaconing?
An FDDI frame or Token Ring frame that points to serious problem with the ring, such as a broken cable. The beacon frame carries the address of the station thought to be down.
What are NetBIOS and NetBEUI?
NetBIOS – Network Basic Input / Output System
An application-programming interface (API) that can be used by programs on a local area network (LAN). NetBIOS provides programs with a uniform set of commands for requesting the lower-level services required to manage names, conduct sessions, and send datagrams between nodes on a network.
NetBEUI – NetBIOS Extended User Interface
An improved version of the NetBIOS protocol, a network protocol native to Microsoft Networking. It is usually used in small, department-size local area networks (LANs) of 1 to 200 clients. It can use Token Ring source routing as its only method of routing.
What is Cladding?
A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.
What is Attenuation?
In communication weakening or loss of signal energy, typically caused by distance.
What is MAC address?
The address for a device as it is identified at the Media Access Control (MAC) layer in the network architecture. MAC address is usually stored in ROM on the network adapter card and is unique.
What is ICMP?
ICMP – Internet Control Message Protocol
It is a Network Layer Internet protocol, which can report errors and status information. We can use the ping command to send ICMP echo request messages and record the receipt of ICMP echo reply messages. With these messages, we can detect network or host communication failures and troubleshoot common TCP/IP connectivity problems.
What is difference between ARP and RARP?
ARP – Address Resolution Protocol
The protocol that traces IP addresses to MAC addresses.
RARP – Reverse Address Resolution Protocol
The protocol within the TCP/IP stack that maps MAC addresses to IP addresses.
What is the difference between TFTP and FTP application layer protocols?
TFTP – Trivial File Transfer Protocol
A stripped down version of FTP, easy to use and fast. TFTP has no Directory browsing, no Authentication and insecure it can only send and receive files.
FTP – File Transfer Protocol
The TCP/IP protocol used for transmitting files between network nodes. FTP allows access to both Directories and files, manipulating directories, typing file contents and copying files between hosts.
Explain 5-4-3 rule?
In a Ethernet network, between any two points on the network, there can be no more than five network segments or four repeaters, and of those five segments only three of segments can be populated.
What MAU?
MAU – Multistation Access Unit
What is the difference between routable and non- routable protocols?
Routable protocols can work with a router and can be used to build large networks. Non-Routable protocols are designed to work on small, local networks and cannot be used with a router.
What is logical link control?
One of two sublayers of the data link layer of OSI reference model, as defined by the IEEE 802 standard. This sublayer is responsible for error detection but not correction, flow control and framing.
What is Virtual Channel?
A logical circuit that is created by Virtual channel links. It carries data between two endpoints in a network.
The other name for Virtual Channel is Virtual Circuit.
What is Virtual Path?
Along any transmission path from a given source to a given destination, a group of virtual circuits can be grouped together into what is called path.
What is Packet Filter?
What is multicast routing?
Sending a message to a group multicast address is called multicasting, and its routing algorithm is called multicast routing.
What is IGP (Interior Gateway Protocol)?
Any protocol used by an internetwork to exchange routing data within an autonomous system. E.g. RIP, IGRP and OSPF.
What is EGP (Exterior Gateway Protocol)?
It is the protocol the routers in neighboring autonomous systems use to identify the set of networks that can be reached within or via each autonomous system.
What is Autonomous System?
A group of Networks under mutual administration that share the same routing methodology. Autonomous Systems are subdivided by Areas and must be assigned an individual 16-bit number by the IANA.
What is BGP (Border Gateway Protocol)?
It is a protocol used to advertise the set of networks that can be reached within an autonomous system. BGP enables this information to be shared with the autonomous system. This is newer than EGP (Exterior Gateway Protocol).
What is Gateway-to-Gateway protocol?
It is a protocol formerly used to exchange routing information between Internet core routers.
What is Kerberos?
An authentication mechanism used to verify user or host identity. Kerberos uses encryption to prevent intruders from discovering passwords and gaining unauthorized access to files.
What is OSPF (Open Shortest Path First)?
OSPF is the first Open Standard Link State Routing Protocol.
It’s a Classless Routing Protocol meaning when updates are sent they send both IP address and Subnet mask.
Administrative Distance is 110.
Metric used is Cost i.e. Cost= 108
---------------
Bandwidth
OSPF uses algorithm to build Routing Table called Dijisktra.
Sends only Incremental and Triggered updates. Route updates sent within the routers will be secured with the help of MD5 encrypted password.
Routing updates are sent as Multicast addresses i.e.
224.0.0.5 – SPF (all OSPF routers)
224.0.0.6 – Designated router and Backup Designated router
OSPF maintains 3 types of Routing table i.e. Routing Table (Dijisktra), Topology Table (SPF) and Neighborship Table.
In OSPF Routers can be connected in two methods i.e.
Point-to-Point Link
Point to Multipoint Link
In OSPF a single large Autonomous system is break into small areas. There should be atleast one area by name Area 0. It’s called as Backbone Area.
The Router that connects more than one Area is called as Area Border Routers.
The Router that connects to other Autonomous system is called as Autonomous System Boundary Router.
Router ID
If the priority is set 1 to all the routers then there is a tie in priority, in this case it will check if there is any loopback address is given to any router if not the router with highest value of IP address will be elected as Router ID.
This router will be then called as Designated Router and the router with less value of IP address after Designated Router will be called as Backup Designated Router.
If a Router has all interfaces existing in single area than that router is called as Internal Router.
Whenever a router send routing updates to DR and BDR it uses Destination address as 224.0.0.6 and when DR send updates to all the routers it uses Destination address as 224.0.0.5.
In OSPF routing updates are called as Link State Advertisements.
If an OSPF router wants to send updates to other OSPF router then it should carry 3 requirements i.e.
Hello Packets Received
It contains Area Id, Uptime, Password, Hello Interval, Dead Interval, Neighborship Table and Router Id.
Point-to-Point Link Point to Multipoint Link
Halo Interval – 10 Halo Interval – 30
Dead Interval – 40 Dead Interval – 120
Adjacency Built
If both router interfaces belongs to same Area, same Password then Hallo and Dead Intervals should be set same.
Neighborship Built
If both routers are adjacent to each other then Neighborship is built in Routers.
When one routerRA sends updates i.e. Link State Advertisements to other routerRB it will send that update to Topology Database of routerRB and will run an algorithm SPF on routerRB to create a new Topology Table. After that Dijisktra Algorithm is run to find the best path and that entry will be put in Routing Table.
The router when sends Hallo packets to other router a Neighborship Table is set on that Router.
What is SLIP (Serial Line Internet Protocol)?
An industry standard serial encapsulation for point-to-point connections that supports only a single routed protocol, TCP/IP.
What is RIP (Routing Information Protocol)?
Rip run on any Routers hence called as Open Standard Distance Vector Routing Protocol.
It’s a classful routing protocol meaning when updates are sent they send only IP address but not subnet mask.
Administrative Distance is 120.
Metric used is Hop counts (number of routers to cross to reach the destination).
Rip uses algorithm name Bellman Ford Algorithm to determine the best path selection.
Supports maximum 15 Hops.
Supports 6 paths if there is a tie in metric i.e. same metric.
RIP Timers
Route update timer – 30seconds
Route invalid timer – 180 seconds
Holddown timer – 180 seconds
Route flush timer – 240 seconds
What are the advantages and disadvantages of the three types of routing tables?
What is the HELLO protocol used for?
The HELLO protocol uses time instead of distance to determine optimal routing. It is an alternative to the Routing Information Protocol.
What is the difference between interior and exterior neighbor gateways?
Interior gateways connect LANs of one organization, whereas exterior gateways connect the organization to the outside world.
What protocol do DNS name servers use?
DNS uses UDP for communication between servers. It offers a connectionless datagram service that guarantees neither delivery nor correct sequencing of delivered packets (much like IP).
What is a DNS resource record?
A resource record is an entry in a name server's database. There are several types of resource records used, including name-to-address resolution information. Resource records are maintained as ASCII files.
BOOTP helps a diskless workstation boot. How does it get a message to the network looking for its ip address?
A protocol used primarily on TCP/IP networks to configure diskless workstations. BOOTP sends a UDP message with a subnetwork broadcast address and waits for a reply from a server that gives it the IP address.
What is anonymous FTP and why would you use it?
Anonymous FTP enables users to connect to a host without using a valid login and password. Usually, anonymous FTP uses a login called anonymous or guest, with the password usually requesting the user's ID for tracking purposes only. Anonymous FTP is used to enable a large number of users to access files.
How do Data Link layer addresses and Network addresses differ? Give a description of each.
Besides the names suggesting that addresses reside at different layers, other differences do exist. Data Link layer addresses are assigned by the manufacturer and identify the actual hardware device. A Network layer address is a logical address assigned by the network administrator to identify a device running a Network layer protocol, such as IP.
What are the differences or similarities, if any, between repeaters, hubs, and concentrators?
First, they are all Physical layer devices. Repeaters regenerate and amplify the signal traveling on the wire to extend the normal distance limitation of the signal. A repeater can connect two network segments. A hub and a concentrator are the same thing, with hub being the more common term used today. Hubs are repeaters with 8–24 ports. When one machine attached to the hub sends anything over the network, all the devices attached to the hub receive that signal.
Describe, in general terms, the reasons for implementing LAN segmentation.
It confines user traffic to a segment and addresses and solves distance limitation problems. Segmentation also cuts down on the traffic generated by broadcasts and multicasts, and thereby increases performance. Because of the reduction of the size of the segment, collisions and overall traffic also are reduced.
Which of the three switching methods is fastest, and why?
Cut-Through switching is the fastest method because the switches read only the first six bytes of the frame before forwarding it.
What services do bridges and switches provide?
Bridges and switches can determine whether a frame is destined for the local network segment or needs to be forwarded to another network segment based on the destination MAC address.
What are some of the advantages to using bridging and switching instead of routing?
Increased overhead and latency
Reduced overhead and latency
Broadcast propagation
Lower equipment costs
Answer A is incorrect because it is a negative aspect of routing as compared to switching. Answer B is correct because bridges and switches look only at Data Link layer information, whereas routers must process all the logical address information in the route tables. Answer C is incorrect because switches do not have this effect. Answer D is incorrect because switches are now very sophisticated and can cost as much as routers.
What would be the best network segmentation device if you wanted to connect two dissimilar networks, such as Ethernet and Token-Ring?
A bridge or a switch
A concentrator or a hub
A router
A gateway
Answer A is incorrect because bridges and switches can’t perform protocol translation. Answer B is incorrect because neither a concentrator nor a hub can segment a network. Answer C is correct because routers can provide translation between dissimilar protocols, among other things. Answer D is incorrect because a gateway functions as a translator, not a segmentation device.
Why is overhead or latency associated with routers? (Choose all that apply.)
Routers must work at layer 3, which is inherently slower.
Routers must examine the frame header before passing it.
Routers must hold a frame for a given period of time for security purposes.
Routers must translate the signal, but then the signal can cut through directly.
Answer A is correct because resolving those addresses is more time consuming. Answer B is correct because the router must examine and consider the frame header detail before passing it, which slows processing. Answers C and D are incorrect because they are simply not accurate.
Which of the following represents Physical layer devices?
Repeaters, bridges, and concentrators
Repeaters, hubs, and concentrators
Repeaters, routers, and bridges
Repeaters, routers, and switches
Answer B is correct because repeaters, hubs, and concentrators comprise the only combination that resides at the Physical layer. Answers A, C, and D are combinations of devices that reside at different layers.
How do routers make routing decisions?
They build tables and make their decisions based on those tables.
They perform lookups and make their decisions dynamically with discovery.
They use hello packets to discover routes on the fly.
They query NetBIOS cache for the appropriate paths.
Answer A is correct because routing decisions are made based on the contents of routing tables. Answer B is incorrect because routers are incapable of making decisions without tables already in place. Answer C is incorrect because hello packets are used to calculate routes when new routers are added to a network. Answer D is incorrect because it is simply inaccurate.
Choose the devices that are used for Data Link layer segmentation.
Concentrators and switches
Routers and bridges
Bridges and switches
Bridges and hubs
Answer A is incorrect because concentrators reside at the Physical layer and switches at the Data Link layer. Answer B is incorrect because routers are level 3 devices and bridges are level 2 devices. Answer C is correct because bridges and switches reside at the Data Link layer. Answer D is incorrect because bridges reside at the Data Link layer and hubs at the Physical layer.
What is an advantage of having a VLAN (Virtual LAN)?
Traffic control between VLANs is processor intensive.
Broadcasts of multicast traffic are contained within one VLAN.
They’re more flexible because they enable device assignment only on a port-by-port basis.
With VLANs, users are not inherently isolated by group.
Answer A is incorrect because there is nothing more or less processor intensive about VLANs. Answer B is incorrect because there is no such thing as a broadcast of multicast traffic; the words broadcast and multicast are mutually exclusive. Answer C is correct because VLANs extend the flexibility of LANs by enabling the port-by-port isolation of users and assignment to distinct VLANs if desired. Answer D is incorrect because VLANs by their definition segment workgroups.
Which two characteristics describe Store and Forward switching?
The entire frame is copied into the buffer.
The frame is forwarded based on the first six bytes.
It provides higher throughput.
It provides error checking.
Answers A and D are correct because Store and Forward switching copies the entire frame into the buffer before forwarding, which also provides for error checking. Answers B and C are incorrect because they describe Cut-Through.
Which two characteristics describe Cut-Through switching?
The entire frame is copied into the buffer.
The frame is forwarded based on the first six bytes.
It provides higher throughput.
It provides error checking.
Answers B and C are correct because Cut-Through switching provides forwarding based on what is contained in the first six bytes of the frame, which provides higher throughput. Answers A and D are incorrect because they describe Store and Forward switching.
Name the Cisco proprietary protocol that allows VLANs to be managed within domains.
VTP (VLAN Trunking Protocol) allows multiple VLANs to be managed within a single VTP domain.
Name the three VTP modes in which a switch can operate.
VTP switches operate in one of three modes: server, client, or transparent.
Name the Cisco proprietary protocol used on Fast Ethernet VLAN trunk links.
ISL (Inter-Switch Link) protocol is used to encapsulate VLAN traffic over Fast Ethernet trunk links.
At what layer of the OSI model do VLANs operate?
VLANs operate at layer 2 of the OSI model.
To allow Inter-VLAN communication, what does your router require?
You need a router that has some kind of viable trunking connection, such as Fast Ethernet (ISL), and must be configured with subinterfaces.
Choose one method of decreasing broadcasts across a switched network.
Set up an Intra-LAN.
Set up a workgroup banded by a server cluster.
Set up a VLAN to isolate traffic.
Set up a firewall to isolate traffic.
Answers A and B are incorrect because they are simply false. Answer C is correct because each VLAN becomes its own broadcast domain. Answer D is incorrect because a firewall is meant to shelter internal networks from intrusion from the outside.
Choose two benefits of VLAN implementation.
VLANs incorporate only one router per routed subnet.
VLANs control broadcasts.
VLANs amplify broadcasts.
VLANs ease security restrictions.
VLANs provide increased network security.
Answer A is incorrect because routers are not at all necessary for a VLAN to operate. Answers B and E are correct because VLAN implementation controls broadcasts and provides isolation, therefore security. Answers C and D are simply incorrect.
What is the purpose of a trunking protocol?
To connect the backbone of a primary VLAN to the backbone of a secondary VLAN
For one switch fabric to be integrated with another switch fabric
For a VLAN on one switch to be linked to a VLAN on another switch
To enable multiple trunking protocols to communicate
Answers A is incorrect because it uses wrong terminology. Answer B is incorrect because switch fabric is a hardware-related component of a switch and belongs to one switch only. Answer C is correct because trunking protocols allow management of VLANs with similar or dissimilar trunking protocols. Answer D is incorrect because a trunking protocol does not enable multiple trunking protocols to communicate.
Choose the encapsulation protocol used on Fast Ethernet links.
Cisco Switch Link
Dedicated Switch Link
Inter-Switch Link
VLAN Switch Link
Answer C is correct because Inter-Switch Link protocol is the encapsulation protocol used on Fast Ethernet links. Answers A, B, and D is incorrect because no such links exist.
At which layer of the OSI model does ISL function?
Data Link layer
Network layer
Physical layer
LLC Data Link sublayer
Answer A is correct because ISL functions at the Data Link layer of the OSI model. Answers B and C are incorrect because ISL does not function at those layers of the OSI model. Answer D is incorrect because the specific sublayer does not have any distinction in this context.
Which method is used by VTP to convey VLAN configuration information within its management domain?
Through directed broadcasts
Through LSA’s local service advertisements
Through multicast advertisements
Through port flooding
Answer C is correct because multicast advertisement convey configuration information to all connected switches in the same management domain. Answers A, B, and D is incorrect because they do not convey information within management domains.
In ATM LANE, what factor determines the type of trunking protocol used?
The link type
The encapsulation mode
The density of VLANs
The ATM LANE Module type
Answer A is correct because the link type determines the type of trunking protocol used. Answers B and C are incorrect because they are simply false. Answer D is incorrect because the ATM LANE Module is a hardware card and does not affect trunking protocols.
What is VTP designed to do?
It enables an administrator to manage VLANs across multiple trunk links.
It enables an administrator to manage VLANs across dissimilar trunking protocols.
It enables an administrator to merge the management duties of more than two trunk links together.
It is used to synchronize VTP advertisements across multiple trunk links.
Answer A is incorrect because trunk links do not address the aspect of communication. Answer B is correct because VTP is designed to enable an administrator to manage VLANs running dissimilar trunking protocols. Answer C is incorrect because a trunk link does not necessary entail management duties on its own. Answer D is incorrect because it is simply false.
What is a limitation of Intra-VLAN traffic?
Communication is limited to VLANs directly connected to a router.
Communication is limited to VLANs off the same switch backplane.
Communication is limited to devices within the same VLAN.
Communication is limited to devices between VLANs.
Answer A is incorrect because VLANs are connected for Inter-VLAN communication. Answer B is incorrect because the backplane is where traffic is actually switched, and it is a hardware component. Answer C is correct because that is the very definition of Intra-VLAN traffic. Answer D is incorrect because VLANs cannot talk to each other without a router.
VTP (Virtual Trunking Protocol) exists at which layer and for what purpose?
Layer 2, to maintain VLAN configuration consistency
Layer 2, to maintain trunking protocol synchronization
Layer 2, to maintain domain synchronization
Layer 3, to maintain access lists
Answer A is correct because VTP operates at layer 2 and maintains VLAN configuration consistency. Although the OSI layer is correct, answers B and C are incorrect because the second portion of the answers is incorrect. Answer D is incorrect because VTP and switching do not operate at layer 3 and access lists are maintained on routers.
What two basic steps are necessary to create access list filters?
The first step is to build the list at global configuration mode using the access-list command followed by an access list number signifying the type. The second step is to apply the list to an interface by using the [protocol type] access-group command followed by the access list number and parameters.
Identify the appropriate access list range values used to create access lists.
IP standard access list = 1–99
IP extended access list = 100–199
IPX standard access list = 800–899
IPX extended access list = 900–999
IPX SAP filter = 1000–1099
What is the purpose of a wildcard mask?
To enable an administrator to apply an access list rule to a group of hosts or subnets by masking off bits within an IP address, making the bit positions within the mask variable.
Name the access list keywords.
any = 0.0.0.0 255.255.255.255
host = specific IP address of an end host (192.16.10.2 0.0.0.0)
How does the direction in which an access list is applied affect datagram processing?
Access lists applied to an interface in an inbound direction determine whether a datagram received on an interface will be forwarded or blocked. Access lists applied to an interface in an outbound direction determine whether a datagram already received will be forwarded out that interface.
What is the access list number range used to identify an IP standard access list?
0–100
1–100
1–99
1–10
101–199
Answer C is correct because the correct value range to identify an IP standard access list is 1–99. Answers A, B, D, and E are incorrect because they are not ranges used to identify an IP standard access list.
Which of the following represents the default wildcard mask value?
0.0.0.0
255.255.255.255
0.0.255.255
255.255.255.0
Answer A is correct because, if unspecified, the default mask used is 0.0.0.0. Answers B and C are incorrect because neither are the default mask. Answer D is incorrect because it is a regular mask, which is not used for wildcard masking.
Write the command that would apply access list 100 to interface E0 in an outbound direction. (Assume you are already at interface configuration mode of the Ethernet interface.)
IP access-group 100 out
IP access-list 100 out
IP access-group 100 in
IP access-group E0 out
Answer A is correct because IP access-group 100 out is the command that would apply access list 100 to interface E0 in an outbound direction. Answers B, C, and D are simply incorrect.
Which of the following commands creates a standard IP extended access list that enables ping echo requests to be sent from any host on network 166.10.0.0 to network 155.10.0.0?
Access-list 12 permit IP 166.10.0.0.0.0.255.255 host 155.10.0.0
Access-list 120 permit ICMP 166.10.0.0 0.0.255.155 155.10.0.0 0.0.0.255 eq echo
Access-list 120 permit 166.10.0.0.0.0.255.255 host 155.10.0.0
Access-list 120 permit ICMP 166.10.0.0 0.0.255.255 155.10.0.0 0.0.255.255 eq echo
Answer A is incorrect because the access list number is not an extended list number. Also, the protocol type is IP not ICMP, and the destination is specifying the host keyword but using a subnet value instead, which is invalid. Answer B is incorrect because it uses an incorrect inverse mask for the destination network. Answer C is incorrect because it does not specify the protocol after the permit statement and also is using the host keyword with the destination network. Answer D is correct because it uses a valid access list number and syntax to forward ICMP echo requests.
Write the command to view all access lists created on your router regardless of protocol.
show access-lists
show ip access-lists
show ipx interfaces
show ipx servers
Answer A is correct because show access-lists enables you to view all access lists created on your router regardless of protocol. Answers B, C, and D are incorrect because these commands do not enable you to perform that specific function.
Which of the following best describes the function of the following access list line?
Access-list 87 permit 145.19.2.1 0.0.0.0 155.6.0.0 0.0.255.255
Any host on subnet 155.6.0.0 can access host 145.19.2.1.
It is an IPX standard access list allowing host 145.19.2.1 to access any host on subnet 155.6.0.0.
It is an extended IP access list allowing hosts on network 145.19.0.0 to access hosts on network 145.19.0.0, which can access host 155.6.255.255.
It is an IP standard access list enabling host 145.19.2.1 to access any host on subnet 155.6.0.0.
Answers A and C are incorrect because they do not state the actions of this access list correctly. Answer B is incorrect because this is not an IPX standard list. Answer D is correct because it correctly describes the access list behavior.
Which of the following commands applies IPX SAP filter 1010 to an interface in the outbound direction?
IPX access-group 1010 out
IPX output-sap-filter 1010
IPX output sap-filter 1010
IPX-sap-filter 1010 out
Answer A is incorrect because it is the syntax used to define a standard or extended list. Answer B is correct because it uses the correct syntax. Answer C is incorrect because it is missing the hyphen between the output and sap commands. Answer D is incorrect because it is a completely invalid command.
Which command can you use to display a list of access list filters configured on your router for IP only?
show IP access-lists
show access-lists
show IPX interfaces
show IPX servers
Answer A is correct because show IP access-lists enables you to display a list of access list filters configured on your router for IP only. Answers B, C, and D are incorrect because these commands do not enable that specific function.
Write the command to bind IPX extended access list 901 to interface serial 0 on an inbound direction.
IPX access-group 901 in
IPX access-group 901 S0 out
IPX access-group 910 in
IPX access-group 901 out
Answer A is correct because IPX access-group 901 in is the command that will bind the IPX extended access list 901 to interface serial 0 on an inbound direction. Answers B, C, and D are incorrect because they are simply false.
Which two of the following commands will enable Telnet traffic from all hosts on network 166.10.0.0 to be forwarded to the Telnet server 137.2.10.1?
Access-list 110 permit TCP 166.10.0.0 0.0.255.255 host 137.2.10.1 eq Telnet
Access-list 99 permit TCP 166.10.0.0 0.0.255.255 137.2.10.1 0.0.0.0. eq 23
Access-list 110 permit TCP 166.10.0.0 0.0.255.255 137.2.10.1 0.0.0.0 eq 23
Access-list 110 permit IP 166.10.0.0 0.0.255.255 137.2.10.1 0.0.0.0. eq 23
Answers A and C are correct. The only difference between the two is that Answer A uses the host keyword and the Telnet keyword instead of a port number. Answer B is incorrect because the access list number is 99, which is used for standard lists. Answer D is incorrect because it uses IP instead of TCP after the permit statement.
CCNA TUTORIAL :
Networking Primer
IP Addressing
An IP address is a unique logical identifier for a node or host connection on an IP network. An IP address is a 32 bit binary number, and represented as 4 decimal values of 8 bits each. The decimal values range from 0 to 255. This is known as "dotted decimal" notation.
Example: 192.189.210.078
It is sometimes useful to view the values in their binary form.
192 .189 .210 .078
11000000.10111101.11010010.1001110
Every IP address consists of network identifier and node identifier. The IP network is divided based on Class of network. The class of network is determined by the leading bits of the IP address as shown below.
Address Classes
There are 5 different address classes. You can determine which class any IP
address is in by examining the first 4 bits of the IP address.
• Class A addresses begin with 0xxx, or 1 to 126 decimal.
• Class B addresses begin with 10xx, or 128 to 191 decimal.
• Class C addresses begin with 110x, or 192 to 223 decimal.
• Class D addresses begin with 1110, or 224 to 239 decimal.
• Class E addresses begin with 1111, or 240 to 254 decimal.
Addresses beginning with 01111111, or 127 decimal, are reserved for loopback and for internal testing on a local machine. Class D addresses are reserved for multicasting. Class E addresses are reserved for future use. They should not be used for host addresses.
Now we can see how the Class determines, by default, which part of the IP address belongs to the network (N) and which part belongs to the Host/node (H).
• Class A: NNNNNNNN.HHHHHHHH.HHHHHHHH.HHHHHHHH
• Class B: NNNNNNNN.NNNNNNNN.HHHHHHHH.HHHHHHHH
• Class C: NNNNNNNN.NNNNNNNN.NNNNNNNN.HHHHHHHH
In the example, 192.189.210.078 is a Class C address so by default the Network part of the address (also known as the Network Address) is defined by the first three octets (192.189.210.XXX) and the node part is defined by the last one octets (XXX.XXX.XXX.078).
In order to specify the network address for a given IP address, the node section is set to all "0"s. In our example, 192.189.210.0 specifies the network address for 192.189.210.078. When the node section is set to all "1"s, it specifies a broadcast that is sent to all hosts on the network. 192.189.210.255 specifies the broadcast address.
Private Subnets
There are three IP network addresses reserved for private networks. The addresses are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. They can be used by anyone setting up internal IP networks, such as an intranet. Internet routers never forward the private addresses over the public Internet.
• Subnet masking
Subnetting an IP Network is done primarily for better utilization of available IP address space, and routing purpose. Other reasons include better organization, use of different physical media (such as Ethernet, WAN, etc.), and securing network resources.
A subnet mask enables you to identify the network and node parts of the address. The network bits are represented by the 1s in the mask, and the node bits are represented by the 0s. A logical AND operation between the IP address and the subnet mask provides the Network Address.
For example, using our test IP address and the default Class C subnet mask, we get:
192.189.210.078: 1100 0000.1011 1101.1101 0010.0100 1110 Class C IP Address
255.255.255.000: 1111 1111.1111 1111.1111 1111.0000 0000 Default Class C subnet mask
192.189.210.0 1100 0000 1011 1101 1101 0010 0000 0000
As can be seen above, by using and AND operator, we can compute the network portion of an IP address. The network portion for the IP address given in the above example is 192.189.210.0, and the host portion of the IP address is 078.
Given below is a table that provides binary equivalent of decimal values.
For binary conversion, take first octet of a given IP address (in dotted decimal form), and lookup the binary value. Then take the second octet and lookup the binary value, and so on.
Binary Conversion Table
Decimal Binary Decimal Binary Decimal Binary Decimal Binary
0 0000 0000 64 0100 0000 128 1000 0000 192 1100 0000
1 0000 0001 65 0100 0001 129 1000 0001 193 1100 0001
2 0000 0010 66 0100 0010 130 1000 0010 194 1100 0010
3 0000 0011 67 0100 0011 131 1000 0011 195 1100 0011
4 0000 0100 68 0100 0100 132 1000 0100 196 1100 0100
5 0000 0101 69 0100 0101 133 1000 0101 197 1100 0101
6 0000 0110 70 0100 0110 134 1000 0110 198 1100 0110
7 0000 0111 71 0100 0111 135 1000 0111 199 1100 0111
8 0000 1000 72 0100 1000 136 1000 1000 200 1100 1000
9 0000 1001 73 0100 1001 137 1000 1001 201 1100 1001
10 0000 1010 74 0100 1010 138 1000 1010 202 1100 1010
11 0000 1011 75 0100 1011 139 1000 1011 203 1100 1011
12 0000 1100 76 0100 1100 140 1000 1100 204 1100 1100
13 0000 1101 77 0100 1101 141 1000 1101 205 1100 1101
14 0000 1110 78 0100 1110 142 1000 1110 206 1100 1110
15 0000 1111 79 0100 1111 143 1000 1111 207 1100 1111
16 0001 0000 80 0101 0000 144 1001 0000 208 1101 0000
17 0001 0001 81 0101 0001 145 1001 0001 209 1101 0001
18 0001 0010 82 0101 0010 146 1001 0010 210 1101 0010
19 0001 0011 83 0101 0011 147 1001 0011 211 1101 0011
20 0001 0100 84 0101 0100 148 1001 0100 212 1101 0100
21 0001 0101 85 0101 0101 149 1001 0101 213 1101 0101
22 0001 0110 86 0101 0110 150 1001 0110 214 1101 0110
23 0001 0111 87 0101 0111 151 1001 0111 215 1101 0111
24 0001 1000 88 0101 1000 152 1001 1000 216 1101 1000
25 0001 1001 89 0101 1001 153 1001 1001 217 1101 1001
26 0001 1010 90 0101 1010 154 1001 1010 218 1101 1010
27 0001 1011 91 0101 1011 155 1001 1011 219 1101 1011
28 0001 1100 92 0101 1100 156 1001 1100 220 1101 1100
29 0001 1101 93 0101 1101 157 1001 1101 221 1101 1101
30 0001 1110 94 0101 1110 158 1001 1110 222 1101 1110
31 0001 1111 95 0101 1111 159 1001 1111 223 1101 1111
32 0010 0000 96 0110 0000 160 1010 0000 224 1110 0000
33 0010 0001 97 0110 0001 161 1010 0001 225 1110 0001
34 0010 0010 98 0110 0010 162 1010 0010 226 1110 0010
35 0010 0011 99 0110 0011 163 1010 0011 227 1110 0011
36 0010 0100 100 0110 0100 164 1010 0100 228 1110 0100
37 0010 0101 101 0110 0101 165 1010 0101 229 1110 0101
38 0010 0110 102 0110 0110 166 1010 0110 230 1110 0110
39 0010 0111 103 0110 0111 167 1010 0111 231 1110 0111
40 0010 1000 104 0110 1000 168 1010 1000 232 1110 1000
41 0010 1001 105 0110 1001 169 1010 1001 233 1110 1001
42 0010 1010 106 0110 1010 170 1010 1010 234 1110 1010
43 0010 1011 107 0110 1011 171 1010 1011 235 1110 1011
44 0010 1100 108 0110 1100 172 1010 1100 236 1110 1100
45 0010 1101 109 0010 1101 173 1010 1101 237 1010 1101
46 0010 1110 110 0110 1110 174 1010 1110 238 1110 1110
47 0010 1111 111 0110 1111 175 1010 1111 239 1110 1111
48 0011 0000 112 0111 0000 176 1011 0000 240 1111 0000
49 0011 0001 113 0111 0001 177 1011 0001 241 1111 0001
50 0011 0010 114 0111 0010 178 1011 0010 242 1111 0010
51 0011 0011 115 0111 0011 179 1011 0011 243 1111 0011
52 0011 0100 116 0111 0100 180 1011 0100 244 1111 0100
53 0011 0101 117 0111 0101 181 1011 0101 245 1111 0101
54 0011 0110 118 0111 0110 182 1011 0110 246 1111 0110
55 0011 0111 119 0111 0111 183 1011 0111 247 1111 0111
56 0011 1000 120 0111 1000 184 1011 1000 248 1111 1000
57 0011 1001 121 0111 1001 185 1011 1001 249 1111 1001
58 0011 1010 122 0111 1010 186 1011 1010 250 1111 1010
59 0011 1011 123 0111 1011 187 1011 1011 251 1111 1011
60 0011 1100 124 0111 1100 188 1011 1100 252 1111 1100
61 0011 1101 125 0111 1101 189 1011 1101 253 1111 1101
62 0011 1110 126 0111 1110 190 1011 1110 254 1111 1110
63 0011 1111 127 0111 1111 191 1011 1111 255 1111 1111
Example Question: Which of the following is a Class C IP address?
A. 10.10.14.118
B. 135.23.112.57
C. 191.200.199.199
D. 204.67.118.54
Correct Answer: D.
Explanation:
IP addresses are written using decimal numbers separated by decimal points. This is called dotted decimal notation of expressing IP addresses. The different classes of IP addresses is as below:
Class Format Leading Bit pattern Network address Range Maximum networks Maximum hosts
A N.H.H.H 0 0-126 127 16,777,214
B N.N.H.H 10 128-191 16,384 65,534
C N.N.N.H 110 192-223 2,097,152 254
Network address of all zeros means "This network or segment".
Network address of all 1s means " all networks", same as hexadecimal of all Fs.
Network number 127 is reserved for loopback tests.
Host (Node) address of all zeros mean "This Host (Node)".
Host (Node) address of all 1s mean "all Hosts (Nodes) " on the specified network.
Subnet masking -II
What we discussed in the previous section is Classful subnet masking. A Subnetmask normally contains the host portion of the bits also. This is called Classless Inter Domain Routing (CIDR). This will enable more networks for a given class of network address. For example, allowing 3 host bits towards subnet portion in our previous IP address, will allow us to offer 2X2X2 or 8 additional subnetworks. Traditionally, all zeros, and all ones subnets are not used, and hence we are left with 6 subnets.
192.189.210.078: 1100 0000.1011 1101.1101 0010.0100 1110 Class C IP Address
255.255.255.224: 1111 1111.1111 1111.1111 1111.1110 0000 Class C subnet mask with 3 additional bits of host portion used for Subnetting.
Broadcast address: 1100 0000.1011 1101.1101 0010.0101 1111 :192.189.210.95
The above is the broadcast address for a given subnet (192.189.210.078). Under Classful routing, the broadcast address would have been 192.189.210.255.
Note that by using Subnetting, we are able to increase the number of networks available within a given IP address. On the otherhand, we will be loosing the number of hosts available within a subnet to 24 or 16 hosts per subnet. Again, all zeros, and all ones host addresses are traditionally reserved for other purposes.
CIDR (Classless InterDomain Routing) notation: Subnet mask is also represented as below:
192.189.210.078/27, where 27 is the number of bits in the network portion of the IP address.
Why use CIDR?
Normally, ISPs allocate the IP addresses for individuals or Corporates. The reason being that it is almost impossible to allocate a classful IP address to every individual or a corporate. Using CIDR, the biggest ISPs are given large pool of IP address space. The ISP's customers such as individual or Corporates are then allocated networks from the big ISP's pool. This kind of arrangement will enable efficient management and utilization of the Internet.
Classful addresses can easily be written in CIDR notation
Class A = A.B.C.D/8, Class B = A.B.C.D/16, and Class C = A.B.C.D/24
Where A,B,C,D are dotted decimal octets.
Example Question:
You have an IP of 156.233.42.56 with a subnet mask of 7 bits. How many hosts and subnets are possible?
A. 126 hosts and 510 subnets
B. 128 subnets and 512 hosts
C. 510 hosts and 126 subnets
D. 512 subnets and 128 hosts
Correct answer: C
Explanation:
Class B network has the form N.N.H.H, the default subnet mask is 16 bits long.
There is additional 7 bits to the default subnet mask. The total number of bits in subnet are 16+7 = 23.
This leaves us with 32-23 =9 bits for assigning to hosts.
7 bits of subnet mask corresponds to (2^7-2)=128-2 = 126 subnets.
9 bits belonging to host addresses correspond to (2^9-2)=512-2 = 510 hosts
Routing Fundamentals
When IP packets travel over the Internet, routing information is exchanged between the devices that control the flow of information over the Internet. These devices are known as routers, and they use the IP address as the basis for controlling the traffic. These devices need to talk the same language to function properly, though they belong to different administrative domains. For example, one router may be in Newyork(US), and the receiving router may be in London (UK). It is necessary that a routing protocol is followed for smooth flow of traffic. Given below are the widely used routing protocols for routing Internet traffic:
• RIP v1
• RIP v2
• OSPF
• IGRP
• EIGRP
• BGP
Notations used: Routing Information Protocol (RIP), Open Shortest Path First (OSPF), Interior Gateway Routing Protocol (IGRP), Enhanced Interior Gateway Routing Protocol (EIGRP), and Border Gateway Protocol (BGP).
One often get confused between a routing protocol and a routed protocol. A routing protocol such as RIP is used to route information packets over the Internet, where as a routed protocol such as IP (or IPX) is the payload (contains data) that get routed from source to the destination.
Routing protocols are primarily distinguished into three types:
• Distance Vector Protocols
• Link State Protocols
• Hybrid Protocols
RIP is an example of distance vector protocol. IS-IS is an example of Hybrid protocol, and OSPF is an example of Link State Protocol.
The table below provides the routing protocol used with different routed protocols:
Routing Protocol Routed Protocol
RIP, OSPF,IS-IS, BGP,EIGRP IP
RIP, NLSP, EIGRP IPX
RTMP, EIGRP AppleTalk
The list of routed, and routing protocols given in the above table is not complete, and given to serve as an example only.
Routing Metric: This is a fundamental measure that routing protocols use for determining appropriate route to deliver packets. Each routing protocol uses its own measure of metric, and a sample of routing metrics used by different routing protocols is given below:
Routing Protocol Metric
RIPv2 Hop count
EIGRP Bandwidth, Delay, Load, Reliability, and MTU
OSPF Cost (Higher bandwidth indicates lower cost)
IS-IS Cost
The best route in RIP is determined by counting the number of hops required to reach the destination. A lower hop count route is always preferred over a higher hop count route. One disadvantage of using hop count as metric is that if there is a route with one additional hop, but with significantly higher bandwidth, the route with smaller bandwidth is taken. This is illustrated in the figure below:
The RIP routed packets take the path through 56KBPS link since the destination can be reached in one hop. Though, the alternative provides a minimum bandwidth of 1MBPS (though using two links of 1MBPS, and 2MBPS each), it represents 2 hops and not preferred by the RIP protocol.
Link State vs. Distance Vector
Distance Vector routing protocols usually send their entire routing table to their nearest neighbors at regular intervals. A router that receives several such routing tables filter the routes and arrive at its own and retransmits it to its neighbouring routers. There will some period of time where different routers hold non-optimized routes initially. After some time, known as convergence time, a final routing table is arrived at by all the routers. A faster convergence time results in a stable network.
RIP, as mentioned earlier uses hop count as the metric for computing a route to a given destination. Other Distance Vector routing protocols, such as IGRP, improve on this by using hop count, bandwidth, current load, cost, and reliability to determine the best path.
Link State routing protocols usually send only the routing changes to every other router within their area. Unlike Distance Vector, routers using Link State routing protocols maintain a picture of the entire network. A router can use this network wide information to determine the best route for traffic.
Example Question:
What is true about IP routing?
A. The frame changes at each hop
B. The source IP address changes at each hop
C. The destination IP address changes at each hop
D. The hardware interface addresses remain constant
Correct answer: A
Explanation:
IP Packets are transported from source network to the destination network by what is known as routing. Hop-by-hop routing model is used by the Internet for delivery of packets. At each hop, the destination IP address is examined, the best next hop is determined by the routing protocol (such as RIP, OSPF or BGP) and the packet is forwarded by one more hop through this route. The same process takes place at the next hop. During this process, the logical addresses remain same. In an IP network, the logical addresses are IP addresses. The hardware interface addresses, such as MAC address change with each hop.
OSPF Routing Fundamentals
OSPF stands for Open Shortest Path First.
Definition: OSPF is a routing protocol used to determine the best route for delivering the packets within an IP networks. It was published by the IETF to serve as an Interior Gateway Protocol replacing RIP. The OSPF specification is published as Request For Comments (RFC) 1247.
Note that OSPF is a link-state routing protocol, whereas RIP and IGRP are distance-vector routing protocols. Routers running the distance-vector algorithm send all or a portion of their routing tables in routing-update messages to their neighbors.
OSPF sends link-state advertisements (LSAs) to all other routers within the same area. Information on attached interfaces, metrics used, and other variables is included in OSPF LSAs. OSPF routers use the SPF (Shortest Path First) algorithm to calculate the shortest path to each node. SPF algorithm is also known as Dijkstra algorithm.
Advantages of OSPF
• OSPF is an open standard, not related to any particular vendor.
• OSPF is hierarchical routing protocol, using area 0 (Autonomous System) at the top of the hierarchy.
• OSPF uses Link State Algorithm, and an OSPF network diameter can be much larger than that of RIP.
• OSPF supports Variable Length Subnet Masks (VLSM), resulting in efficient use of networking resources.
• OSPF uses multicasting within areas.
• After initialization, OSPF only sends updates on routing table sections which have changed, it does not send the entire routing table, which in turn conserves network bandwidth.
• Using areas, OSPF networks can be logically segmented to improve administration, and decrease the size of routing tables.
Disadvantages of OSPF:
• OSPF is very processor intensive due to implementation of SPF algorithm. OSPF maintains multiple copies of routing information, increasing the amount of memory needed.
• OSPF is a more complex protocol to implement compared to RIP.
OSPF Networking Hierarchy:
As mentioned earlier, OSPF is a hierarchical routing protocol. It enables better administration and smaller routing tables due to segmentation of entire network into smaller areas. OSPF consists of a backbone (Area 0) network that links all other smaller areas within the hierarchy. The following are the important components of an OSPF network:
• Areas
• Area Border Routers
• Backbone Areas
• AS Boundary Routers
• Stub Areas
• Not-So-Stubby Areas
• Totally Stubby Area
• Transit Areas
ABR: Area Border Router
ASBR: Autonomous System Boundary Router
Areas: An area consists of routers that have been administratively grouped together. Usually, an area as a collection of contiguous IP subnetted networks. Routers that are totally within an area are called internal routers. All interfaces on internal routers are directly connected to networks within the area.
Within an area, all routers have identical topological databases.
Area Border Routers: Routers that belong to more than one area are called area border routers (ABRs). ABRs maintain a separate topological database for each area to which they are connected.
Backbone Area: An OSPF backbone area consists of all routers in area 0, and all area border routers (ABRs). The backbone distributes routing information between different areas.
AS Boundary Routers (ASBRs): Routers that exchange routing information with routers in other Autonomous Systems are called ASBRs. They advertise externally learned routes throughout the AS.
Stub Areas: Stub areas are areas that do not propagate AS external advertisements. By not propagating AS external advertisements, the size of the topological databases is reduced on the internal routers of a stub area. This in turn reduces the processing power and the memory requirements of the internal routers.
Not-So-Stubby Areas (NSSA): An OSPF stub area has no external routes in it. A NSSA allows external routes to be flooded within the area. These routes are then leaked into other areas. This is useful when you have a non-OSPF router connected to an ASBR of a NSSA. The routes are imported, and flooded throughout the area. However, external routes from other areas still do not enter the NSSA.
Totally Stubby Area: Only default summary route is allowed in Totally Stubby Area.
Transit Areas: Transit areas are used to pass traffic from an adjacent area to the backbone. The traffic does not originate in, nor is it destined for, the transit area.
Link State Advertisements (LSAs):
It is important to know different Link State Advertisements (LSAs) offered by OSPF protocol.
Type 1: Router link advertisements generated by each router for each area it belongs to. Type 1 LSAs are flooded to a single area only.
Type 2: Network link advertisements generated by designated routers (DRs) giving the set of routers attached to a particular network. Type 2 LSAs are flooded to the area that contains the network.
Type 3/4: These are summary link advertisements generated by ABRs describing inter-area routes. Type 3 describes routes to networks and is used for summarization. Type 4 describes routes to the ASBR.
Type 5: Generated by the ASBR and provides links external to the Autonomous System (AS). Type 5 LSAs are flooded to all areas except stub areas and totally stubby areas.
Type 6: Group membership link entry generated by multicast OSPF routers.
Type 7: NSSA external routes generated by ASBR. Only flooded to the NSSA. The ABR converts LSA type 7 into LSA type 5 before flooding them into the backbone (area 0).
Area Restriction
Normal None
Stub Type 5 AS-external LSA NOT allowed
NSSA Type 5 AS-external LSAs are NOT allowed, but Type 7 LSAs that convert to Type 5 at the NSSA ABR can traverse
Totally Stubby Type 3, 4 or 5 LSAs are NOT allowed except the default summary route
Cisco IOS An Introduction
Cisco IOS (short for Internetwork Operating System) is the software used on a majority of Cisco Systems routers and switches. IOS consists of routing, switching, internetworking and telecommunications functions in a multitasking operating system.
Cisco IOS has uses command line interface (CLI), and provides a fixed set of multiple-word commands. A Cisco IOS command line interface can be accessed through either a console connection, modem connection, or a telnet session. The set of commands available at any particular level is determined by the "mode" and the privilege level of the current user.
Cisco IOS follows a command hierarchy, with each level offering different set of commands All commands are assigned a privilege level, from 0 to 15, and can only be accessed by users with the necessary privilege. Through the CLI, the commands available to each privilege level can be defined.
Some of the widely used command hierarchy levels are given below:
User EXEC level: This is the level that a connected user is allowed initially. User EXEC allows access to a limited set of basic monitoring commands. A ">" sign denotes User EXEC mode.
Privileged EXEC level: Privileged EXEC level allows access to all router commands including router configuration and management commands. This level is usually password protected for security reasons. A "#"sign denotes privileged EXEC mode.
When a user is connected to a Cisco IOS, a User EXEC prompt appears. Now, the user can enter privileged EXEC mode by typing the password shown as below:
Router> enable
Password: [enable password]
Router# configure terminal
Router(config)#
Global configuration mode: "Global configuration mode" provides commands to change the system's configuration. This is typically represented by "(config)#" sign as shown in the above example.
Interface configuration mode: "Interface configuration mode" provides commands to change the configuration of a specific interface of the router. An interface configuration mode is denoted by "(config-in)#".
A summary of Cisco IOS router command prompt is given below:
Prompt Explanation
Router> User EXEC mode
Router# Privileged EXEC mode
Router(config)# Global configuration mode. # sign indicates this is only accessible at privileged EXEC mode.
Router(config-if)# Interface level configuration mode.
Router(config-router)# Routing engine level within configuration mode.
Router(config-line)# Line level (vty, tty, async) within configuration mode.
Context Sensitive Help
Cisco IOS CLI offers context sensitive help. At any time during an EXEC session, a user can type a question mark (?) to get help.
Two types of context sensitive help are available:
• Word help and
• Command syntax help.
Word help: Word help can be used to obtain a list of commands that begin with a given character string. To use word help, type in the characters in question followed immediately by the question mark (?). The following is an example of word help:
Router# co?
configure connect copy
Command syntax help: Command syntax help can be used to obtain a list of commands, keyword, or argument options that are available starting with the keywords that the user had already entered. To use command syntax help, enter a question mark (?) after hitting a space. The router will then display a list of available command options with standing for carriage return. The following is an example of command syntax help:
Router# configure ?
memory Configure from NV memory
network Configure from a TFTP network host
terminal Configure from the terminal
Cisco IOS also allows abbreviated commands support. For example, consider the following:
Router#configure terminal
Router(config)#
Router#config term
Router(config)#
Both the above commands to the same job. The IOS correctly interprets the full command words. However, if there is any ambiguity, an error message is generated as below:
Router(config)#c
% Ambiguous command: "c"
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Example Question:
What is the command used to add a banner to a Cisco router configuration?
A. add banner
B. banner motd #
C. motd banner #
D. add banner #
Correct answer: B
Explanation:
The banner is displayed whenever anyone logs in to your Cisco router. The syntax is
"banner motd #
MOTD stands for "Message Of The Day".
# symbol signifies the start of the banner message to the router. You will be prompted for the
message to be displayed. You need to enter "#" symbol at the end of the message, signifying
that the msg has ended.
Alternatively, you can enter the banner in the same line as below:
"banner motd # your message here#
note that you need to begin and end the banner with a delimiter (here # sign).
Cisco Access Control Lists
The Cisco Access Control List (ACL) is are used for filtering traffic based on a given filtering criteria on a router or switch interface. Based on the conditions supplied by the ACL, a packet is allowed or blocked from further movement.
Cisco ACLs are available for several types of routed protocols including IP, IPX, AppleTalk, XNS, DECnet, and others. However, we will be discussing ACLs pertaining to TCP/IP protocol only.
ACLs for TCP/IP traffic filtering are primarily divided into two types:
• Standard Access Lists, and
• Extended Access Lists
Standard Access Control Lists: Standard IP ACLs range from 1 to 99. A Standard Access List allows you to permit or deny traffic FROM specific IP addresses. The destination of the packet and the ports involved can be anything.
This is the command syntax format of a standard ACL.
access-list access-list-number {permit|deny}
{host|source source-wildcard|any}
Standard ACL example:
access-list 10 permit 192.168.2.0 0.0.0.255
This list allows traffic from all addresses in the range 192.168.2.0 to 192.168.2.255
Note that when configuring access lists on a router, you must identify each access list uniquely by assigning either a name or a number to the protocol's access list.
There is an implicit deny added to every access list. If you entered the command:
show access-list 10
The output looks like:
access-list 10 permit 192.168.2.0 0.0.0.255
access-list 10 deny any
Extended Access Control Lists: Extended IP ACLs allow you to permit or deny traffic from specific IP addresses to a specific destination IP address and port. It also allows you to have granular control by specifying controls for different types of protocols such as ICMP, TCP, UDP, etc within the ACL statements. Extended IP ACLs range from 100 to 199. In Cisco IOS Software Release 12.0.1, extended ACLs began to use additional numbers (2000 to 2699).
The syntax for IP Extended ACL is given below:
access-list access-list-number {deny | permit} protocol source source-wildcard
destination destination-wildcard [precedence precedence]
Note that the above syntax is simplified, and given for general understanding only.
Extended ACL example:
access-list 110 - Applied to traffic leaving the office (outgoing)
access-list 110 permit tcp 92.128.2.0 0.0.0.255 any eq 80
ACL 110 permits traffic originating from any address on the 92.128.2.0 network. The 'any' statement means that the traffic is allowed to have any destination address with the limitation of going to port 80. The value of 0.0.0.0/255.255.255.255 can be specified as 'any'.
Applying an ACL to a router interface:
After the ACL is defined, it must be applied to the interface (inbound or outbound). The syntax for applying an ACL to a router interface is given below:
interface
ip access-group {number|name} {in|out}
An Access List may be specified by a name or a number. "in" applies the ACL to the inbound traffic, and "out" applies the ACL on the outbound traffic.
Example:
To apply the standard ACL created in the previous example, use the following commands:
Rouer(config)#interface serial 0
Rouer(config-if)#ip access-group 10 out
Example Question:
Which command sequence will allow only traffic from network 185.64.0.0 to enter interface s0?
A. access-list 25 permit 185.64.0.0 255.255.0.0
int s0 ; ip access-list 25 out
B. access-list 25 permit 185.64.0.0 255.255.0.0
int s0 ; ip access-group 25 out
C. access-list 25 permit 185.64.0.0 0.0.255.255
int s0 ; ip access-list 25 in
D. access-list 25 permit 185.64.0.0 0.0.255.255
int s0 ; ip access-group 25 in
Correct answer: D
Explanation:
The correct sequence of commands are:
1. access-list 25 permit 185.64.0.0 0.0.255.255
2. int s0
3. ip access-group 25 in
WAN Protocols
1. Comparison of WAN and LAN technologies
2. Serial Links
1. Synchronous and
2. Asynchronous
3. Framing and WAN Protocols
a. HDLC
b. LAP, LAPB, LAPD
c. PPP, and SLIP
d. ISDN
I. ISDN BRI
II. ISDN PRI
e. Frame Relay
a. Frame Relay Protocol Overview
b. Frame Relay Network Operation
VLAN - Virtual Local Area Networks
Some basic knowledge of LANs, different topologies, and working of Local Area Networks is required to proceed further.
What is a VLAN?
To refresh your memory, a Local Area Network (LAN) is a set of connected devices like computers, hubs, and switches sharing the same pool of logical address space. Normally, a router is required to route packets from one LAN to another LAN. Traditionally, all packets within a LAN are broadcast to all other devices connected to that particular LAN.
As a result, a traditional LAN has several disadvantages as below:
• Usable bandwidth is shared among all the devices connected to the LAN
• ALL devices connected within a LAN can hear ALL the packets irrespective of whether the packet is meant for that device or not. It is possible for some unscrupulous node listening to data packets not meant for that.
• Suppose, your organization has different departments. Using a traditional LAN, when any changes take place within the organization, physical cables and devices need to be moved to reorganize the LAN infrastructure.
• A LAN cannot extend beyond its physical boundary across a WAN as in VLANs.
If you are looking for a simple networked solution for a small office, it may be a good idea to have a traditional LAN setup with a few hubs or switches. However, if you are planning for a large building or campus wide LAN for several individual departments, a VLAN is almost essential.
Virtual LANs (VLANs) can be considered as an intelligent LAN consisting of different physical LAN segments enabling them to communicate with each other as if they were all on the same physical LAN segment.
Benefits of VLAN: Several of the disadvantages of traditional LANs can be eliminated with the implementation of VLANs.
1. Improved Performance: In a traditional LAN, all the hosts within the LAN receive broadcasts, and contend for available bandwidth. As a result, the bandwidth is shared among all the connected devices within the LAN segment. If you are running high-bandwidth consumption applications such as groupware or server forms, a threshold point may easily be reached. After a threshold, the users may find the LAN too slow or un-responsive. With the use of VLAN, you can divide the big LAN into several smaller VLANs. For example, if there are two file servers, each operating at 100Mbps, in a traditional LAN both the servers have to share the LAN bandwidth of 100Mbps. If you put both the servers in separate VLANs, then both have an available bandwidth of 100Mbps each. Here the available bandwidth has been doubled.
2. Functional separation of an institute or a company: It is often required to separate the functional groups within a company or institute. For example, it might be necessary to separate HR department LAN from that of Production LAN. Traditionally, it requires a router to separate two physical LANs. However, you can set up two VLANs, one for Finance, and the other for Production without a router. A switch can route frames from one VLAN to another VLAN. With VLAN's it is easier to place a workgroup together eventhough they are physically in different buildings. In this case Finance VLAN does not forward packets to Production VLAN, providing additional security.
3. Ease of Network Maintenance:
Network maintenance include addition, removal, and changing the network users. With traditional LANs, when ever a User moves, it may be necessary to re-configure the user work station, router, and the servers. Some times, it may also be necessary to lay the cable, or reconfigure hubs and switches. If you are using VLANs, many of these reconfiguration tasks become unnecessary. For example, you can avoid network address configuration on the work station and the corresponding router if you use VLAN. This is because, routing traffic within VLANs doesn't require a router.
However, VLAN's add some administrative complexity, since the administration needs to manage virtual workgroups using VLANs.
4. Reduced Cost
VLANs minimize the network administration by way of reduced maintenance on account of workstation addition/deletion/changes. This in turn reduce the costs associated with LAN maintenance.
5. Security
Using a LAN, all work stations within the LAN get the frames meant for all other work stations within the broadcast domain. Since a VLAN splits the broadcast domain into two or more, it is possible to put work stations sharing sensitive data in one VLAN, and other work station in another VLAN. Of course, if two VLANs are not sufficient, you can split the work stations into as many VLANs as required. VLAN's can also be used to set up firewalls, restrict access, and send any intrusion alerts to the administrator.
Example:
Question: Your network has 100 nodes on a single broadcast domain. You have implemented VLANs and segmented the network to have 2 VLANs of 50 nodes each. The resulting broadcast traffic effectively:
A. Increases two fold
B. Remains same
C. Decreases by half
D. Increases 4 fold
Ans: C
Explanation: By implementing VLANs, the effective broadcast traffic decreases, since VLANs do not forward the broadcast traffic from one VLAN to another.
LANs and VLANs
Traditional LAN segmentation: Using traditional LAN segmentation, all the segments will be in the same broadcast domain. This effectively, reduces the efficiency of the network. A traditional LAN segmentation is shown below.
Figure 1: Traditional LAN Segmentation
VLANs: Using VLANs, the broadcast domain gets divided into the number of VLANs. If there are three VLANs, as shown in the figure, the broadcast domain will be split into three.
Figure 2: Segmentation using VLANs
Logical View: Given below is the logical view of segmentation using VLANs. Note that a router is required to route traffic between VLANs, and each VLAN is in different broadcast domain.
Only a single router is shown for simplicity. One or more routers may be used for routing interVLAN traffic.
Figure 3: Logical View of VLANs
VLAN Types
How a Switch distinguishes between VLANs? This is done by associating the work stations to a specific VLAN using specified format. This is known as VLAN membership. Four prominent VLAN membership methods are by port, MAC address, protocol type, and subnet address. Each of these are discussed below:
1. VLAN membership by Port:
Here, you define which ports of a Switch belong to which VLAN. Any work station connected to a particular port will automatically be assigned that VLAN. For example, in a Switch with eight ports, ports 1-4 may be configured with VLAN 1, and ports 5-8 may be configured with VLAN2.
One of the disadvantages of this method is that it requires Switch port reconfiguration whenever a user (of course, with associated workstation) moves from one place to another. VLANs by port association operates at Layer 1 of the OSI model.
2. VLAN membership by MAC Address:
Here, membership in a VLAN is based on the MAC address of the user workstation. A Switch that participates in VLAN, uses the MAC addresses to assign a VLAN to each workstation. When a workstation moves to another place, the corresponding switch automatically discovers the VLAN association based on the MAC address of the workstation. Since the MAC address is normally inseparable from that of the workstation, this method of VLAN membership is more amenable to workstation moves.
This type of VLAN works at Layer 2 of the OSI model.
3. Membership by Protocol Type:
Layer 2 header contains the protocol type field. You can use this information to decide on the VLAN association. For example, all IP traffic may be associated with VLAN 1 and all IPX traffic may be associated with VLAN 2.
4. Membership by IP Subnet Address
In this type of VLAN association, membership is based on the Layer 3 header. The Switch reads the Layer 3 IP address and associates a VLAN membership. Note that even though the Switch accesses Layer 3 information, it still works at Layer 2 of OSI model only. A VLAN Switch doesn't do any routing based on IP address.
Examples:
IP Subnet VLAN
192.23.160.0 1
192.23.161.0 2
112.18.0.0 3
IP Subnet addresses assignment to different VLAN's.
IP address based VLANs allow user moves. However, it is likely to take more time to forward a packet by a Switch because it has to read Layer 3 information. Hence the latency rates may be relatively more using this type of VLAN membership.
Communication Between VLANs
Communicating within VLANs: There are different protocols available for communicating between VLANs. These encapsulation schemes are also known as VLAN trunking protocols. These protocols are based on Layer 2 of the OSI model.
These are:
1. Inter-Switch Link Protocol (ISL)
2. IEEE 802.10 Protocol
3. IEEE 802.1Q Protocol
4. ATM LANE Protocol
5. ATM LANE Fast Simple Server Replication Protocol (FSSRP)
Inter-Switch Link Protocol (ISL): The ISL protocol is used to interconnect two VLAN-capable Ethernet, Fast Ethernet, or Gigabit Ethernet devices. Here, VLAN information is tagged to the standard Ethernet frame. The packets on the ISL link contain a standard Ethernet, FDDI, or Token Ring frame and the VLAN information associated with that frame. ISL is a Cisco proprietary protocol.
IEEE 802.10 Protocol: This protocol provides connectivity between VLANs. The protocol incorporates authentication and encryption techniques to ensure data confidentiality and integrity. The protocol operates at layer 2 of OSI model, and hence ensures greater efficiency.
IEEE 802.1Q Protocol: This protocol is used to interconnect multiple switches and routers, and for defining VLAN topologies. IEEE 802.1Q is the industry standard for communicating within VLANs.
ATM LANE Emulation Protocol (LANE): Using LANE, you can benefit from the legacy LAN hardware. The LANE protocol operates over traditional LAN, emulating a broadcast environment like IEEE802.3. LANE makes. LANE allows standard LAN drivers like NDIS and ODI to be used. Applications can use normal LAN functions without the underlying complexities of the ATM implementation. Client work stations need LAN Emulation Client for running LANE protocol. The switches or routers also need to support appropriate LANE functionalities.
ATM LANE Fast Simple Server Replication Protocol (FSSRP): Cisco introduced the ATM LANE Fast Simple Server Replication Protocol (FSSRP). FSSRP provides better network redundancy. If a single LANE server is unavailable due to any technical reasons, the LANE client transparently switches over to the next LANE server and BUS.
Example:
Question:
Match the trunking protocols with respective media:
1. Inter Switch Link A. FDDI
2. LANE B. Fast Ethernet
3. 802.10 C. ATM
Choose the correct choice.
A. 1-> C, 2->B, 3->A
B. 1->B, 2->C, 3->A
C. 1->B, 2->A, 3->C
D. 1->A, 2->B, 3->C
Ans: B
Explanation: ISL, 802.1Q are the VLAN trunking protocols associated with Fast Ethernet. The VLAN trunking protocol defined by 802.10 is associated with FDDI. LANE (LAN Emulation) is associated with ATM.
IP Addressing
An IP address is a unique logical identifier for a node or host connection on an IP network. An IP address is a 32 bit binary number, and represented as 4 decimal values of 8 bits each. The decimal values range from 0 to 255. This is known as "dotted decimal" notation.
Example: 192.189.210.078
It is sometimes useful to view the values in their binary form.
192 .189 .210 .078
11000000.10111101.11010010.1001110
Every IP address consists of network identifier and node identifier. The IP network is divided based on Class of network. The class of network is determined by the leading bits of the IP address as shown below.
Address Classes
There are 5 different address classes. You can determine which class any IP
address is in by examining the first 4 bits of the IP address.
• Class A addresses begin with 0xxx, or 1 to 126 decimal.
• Class B addresses begin with 10xx, or 128 to 191 decimal.
• Class C addresses begin with 110x, or 192 to 223 decimal.
• Class D addresses begin with 1110, or 224 to 239 decimal.
• Class E addresses begin with 1111, or 240 to 254 decimal.
Addresses beginning with 01111111, or 127 decimal, are reserved for loopback and for internal testing on a local machine. Class D addresses are reserved for multicasting. Class E addresses are reserved for future use. They should not be used for host addresses.
Now we can see how the Class determines, by default, which part of the IP address belongs to the network (N) and which part belongs to the Host/node (H).
• Class A: NNNNNNNN.HHHHHHHH.HHHHHHHH.HHHHHHHH
• Class B: NNNNNNNN.NNNNNNNN.HHHHHHHH.HHHHHHHH
• Class C: NNNNNNNN.NNNNNNNN.NNNNNNNN.HHHHHHHH
In the example, 192.189.210.078 is a Class C address so by default the Network part of the address (also known as the Network Address) is defined by the first three octets (192.189.210.XXX) and the node part is defined by the last one octets (XXX.XXX.XXX.078).
In order to specify the network address for a given IP address, the node section is set to all "0"s. In our example, 192.189.210.0 specifies the network address for 192.189.210.078. When the node section is set to all "1"s, it specifies a broadcast that is sent to all hosts on the network. 192.189.210.255 specifies the broadcast address.
Private Subnets
There are three IP network addresses reserved for private networks. The addresses are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. They can be used by anyone setting up internal IP networks, such as an intranet. Internet routers never forward the private addresses over the public Internet.
• Subnet masking
Subnetting an IP Network is done primarily for better utilization of available IP address space, and routing purpose. Other reasons include better organization, use of different physical media (such as Ethernet, WAN, etc.), and securing network resources.
A subnet mask enables you to identify the network and node parts of the address. The network bits are represented by the 1s in the mask, and the node bits are represented by the 0s. A logical AND operation between the IP address and the subnet mask provides the Network Address.
For example, using our test IP address and the default Class C subnet mask, we get:
192.189.210.078: 1100 0000.1011 1101.1101 0010.0100 1110 Class C IP Address
255.255.255.000: 1111 1111.1111 1111.1111 1111.0000 0000 Default Class C subnet mask
192.189.210.0 1100 0000 1011 1101 1101 0010 0000 0000
As can be seen above, by using and AND operator, we can compute the network portion of an IP address. The network portion for the IP address given in the above example is 192.189.210.0, and the host portion of the IP address is 078.
Given below is a table that provides binary equivalent of decimal values.
For binary conversion, take first octet of a given IP address (in dotted decimal form), and lookup the binary value. Then take the second octet and lookup the binary value, and so on.
Binary Conversion Table
Decimal Binary Decimal Binary Decimal Binary Decimal Binary
0 0000 0000 64 0100 0000 128 1000 0000 192 1100 0000
1 0000 0001 65 0100 0001 129 1000 0001 193 1100 0001
2 0000 0010 66 0100 0010 130 1000 0010 194 1100 0010
3 0000 0011 67 0100 0011 131 1000 0011 195 1100 0011
4 0000 0100 68 0100 0100 132 1000 0100 196 1100 0100
5 0000 0101 69 0100 0101 133 1000 0101 197 1100 0101
6 0000 0110 70 0100 0110 134 1000 0110 198 1100 0110
7 0000 0111 71 0100 0111 135 1000 0111 199 1100 0111
8 0000 1000 72 0100 1000 136 1000 1000 200 1100 1000
9 0000 1001 73 0100 1001 137 1000 1001 201 1100 1001
10 0000 1010 74 0100 1010 138 1000 1010 202 1100 1010
11 0000 1011 75 0100 1011 139 1000 1011 203 1100 1011
12 0000 1100 76 0100 1100 140 1000 1100 204 1100 1100
13 0000 1101 77 0100 1101 141 1000 1101 205 1100 1101
14 0000 1110 78 0100 1110 142 1000 1110 206 1100 1110
15 0000 1111 79 0100 1111 143 1000 1111 207 1100 1111
16 0001 0000 80 0101 0000 144 1001 0000 208 1101 0000
17 0001 0001 81 0101 0001 145 1001 0001 209 1101 0001
18 0001 0010 82 0101 0010 146 1001 0010 210 1101 0010
19 0001 0011 83 0101 0011 147 1001 0011 211 1101 0011
20 0001 0100 84 0101 0100 148 1001 0100 212 1101 0100
21 0001 0101 85 0101 0101 149 1001 0101 213 1101 0101
22 0001 0110 86 0101 0110 150 1001 0110 214 1101 0110
23 0001 0111 87 0101 0111 151 1001 0111 215 1101 0111
24 0001 1000 88 0101 1000 152 1001 1000 216 1101 1000
25 0001 1001 89 0101 1001 153 1001 1001 217 1101 1001
26 0001 1010 90 0101 1010 154 1001 1010 218 1101 1010
27 0001 1011 91 0101 1011 155 1001 1011 219 1101 1011
28 0001 1100 92 0101 1100 156 1001 1100 220 1101 1100
29 0001 1101 93 0101 1101 157 1001 1101 221 1101 1101
30 0001 1110 94 0101 1110 158 1001 1110 222 1101 1110
31 0001 1111 95 0101 1111 159 1001 1111 223 1101 1111
32 0010 0000 96 0110 0000 160 1010 0000 224 1110 0000
33 0010 0001 97 0110 0001 161 1010 0001 225 1110 0001
34 0010 0010 98 0110 0010 162 1010 0010 226 1110 0010
35 0010 0011 99 0110 0011 163 1010 0011 227 1110 0011
36 0010 0100 100 0110 0100 164 1010 0100 228 1110 0100
37 0010 0101 101 0110 0101 165 1010 0101 229 1110 0101
38 0010 0110 102 0110 0110 166 1010 0110 230 1110 0110
39 0010 0111 103 0110 0111 167 1010 0111 231 1110 0111
40 0010 1000 104 0110 1000 168 1010 1000 232 1110 1000
41 0010 1001 105 0110 1001 169 1010 1001 233 1110 1001
42 0010 1010 106 0110 1010 170 1010 1010 234 1110 1010
43 0010 1011 107 0110 1011 171 1010 1011 235 1110 1011
44 0010 1100 108 0110 1100 172 1010 1100 236 1110 1100
45 0010 1101 109 0010 1101 173 1010 1101 237 1010 1101
46 0010 1110 110 0110 1110 174 1010 1110 238 1110 1110
47 0010 1111 111 0110 1111 175 1010 1111 239 1110 1111
48 0011 0000 112 0111 0000 176 1011 0000 240 1111 0000
49 0011 0001 113 0111 0001 177 1011 0001 241 1111 0001
50 0011 0010 114 0111 0010 178 1011 0010 242 1111 0010
51 0011 0011 115 0111 0011 179 1011 0011 243 1111 0011
52 0011 0100 116 0111 0100 180 1011 0100 244 1111 0100
53 0011 0101 117 0111 0101 181 1011 0101 245 1111 0101
54 0011 0110 118 0111 0110 182 1011 0110 246 1111 0110
55 0011 0111 119 0111 0111 183 1011 0111 247 1111 0111
56 0011 1000 120 0111 1000 184 1011 1000 248 1111 1000
57 0011 1001 121 0111 1001 185 1011 1001 249 1111 1001
58 0011 1010 122 0111 1010 186 1011 1010 250 1111 1010
59 0011 1011 123 0111 1011 187 1011 1011 251 1111 1011
60 0011 1100 124 0111 1100 188 1011 1100 252 1111 1100
61 0011 1101 125 0111 1101 189 1011 1101 253 1111 1101
62 0011 1110 126 0111 1110 190 1011 1110 254 1111 1110
63 0011 1111 127 0111 1111 191 1011 1111 255 1111 1111
Example Question: Which of the following is a Class C IP address?
A. 10.10.14.118
B. 135.23.112.57
C. 191.200.199.199
D. 204.67.118.54
Correct Answer: D.
Explanation:
IP addresses are written using decimal numbers separated by decimal points. This is called dotted decimal notation of expressing IP addresses. The different classes of IP addresses is as below:
Class Format Leading Bit pattern Network address Range Maximum networks Maximum hosts
A N.H.H.H 0 0-126 127 16,777,214
B N.N.H.H 10 128-191 16,384 65,534
C N.N.N.H 110 192-223 2,097,152 254
Network address of all zeros means "This network or segment".
Network address of all 1s means " all networks", same as hexadecimal of all Fs.
Network number 127 is reserved for loopback tests.
Host (Node) address of all zeros mean "This Host (Node)".
Host (Node) address of all 1s mean "all Hosts (Nodes) " on the specified network.
Subnet masking -II
What we discussed in the previous section is Classful subnet masking. A Subnetmask normally contains the host portion of the bits also. This is called Classless Inter Domain Routing (CIDR). This will enable more networks for a given class of network address. For example, allowing 3 host bits towards subnet portion in our previous IP address, will allow us to offer 2X2X2 or 8 additional subnetworks. Traditionally, all zeros, and all ones subnets are not used, and hence we are left with 6 subnets.
192.189.210.078: 1100 0000.1011 1101.1101 0010.0100 1110 Class C IP Address
255.255.255.224: 1111 1111.1111 1111.1111 1111.1110 0000 Class C subnet mask with 3 additional bits of host portion used for Subnetting.
Broadcast address: 1100 0000.1011 1101.1101 0010.0101 1111 :192.189.210.95
The above is the broadcast address for a given subnet (192.189.210.078). Under Classful routing, the broadcast address would have been 192.189.210.255.
Note that by using Subnetting, we are able to increase the number of networks available within a given IP address. On the otherhand, we will be loosing the number of hosts available within a subnet to 24 or 16 hosts per subnet. Again, all zeros, and all ones host addresses are traditionally reserved for other purposes.
CIDR (Classless InterDomain Routing) notation: Subnet mask is also represented as below:
192.189.210.078/27, where 27 is the number of bits in the network portion of the IP address.
Why use CIDR?
Normally, ISPs allocate the IP addresses for individuals or Corporates. The reason being that it is almost impossible to allocate a classful IP address to every individual or a corporate. Using CIDR, the biggest ISPs are given large pool of IP address space. The ISP's customers such as individual or Corporates are then allocated networks from the big ISP's pool. This kind of arrangement will enable efficient management and utilization of the Internet.
Classful addresses can easily be written in CIDR notation
Class A = A.B.C.D/8, Class B = A.B.C.D/16, and Class C = A.B.C.D/24
Where A,B,C,D are dotted decimal octets.
Example Question:
You have an IP of 156.233.42.56 with a subnet mask of 7 bits. How many hosts and subnets are possible?
A. 126 hosts and 510 subnets
B. 128 subnets and 512 hosts
C. 510 hosts and 126 subnets
D. 512 subnets and 128 hosts
Correct answer: C
Explanation:
Class B network has the form N.N.H.H, the default subnet mask is 16 bits long.
There is additional 7 bits to the default subnet mask. The total number of bits in subnet are 16+7 = 23.
This leaves us with 32-23 =9 bits for assigning to hosts.
7 bits of subnet mask corresponds to (2^7-2)=128-2 = 126 subnets.
9 bits belonging to host addresses correspond to (2^9-2)=512-2 = 510 hosts
Routing Fundamentals
When IP packets travel over the Internet, routing information is exchanged between the devices that control the flow of information over the Internet. These devices are known as routers, and they use the IP address as the basis for controlling the traffic. These devices need to talk the same language to function properly, though they belong to different administrative domains. For example, one router may be in Newyork(US), and the receiving router may be in London (UK). It is necessary that a routing protocol is followed for smooth flow of traffic. Given below are the widely used routing protocols for routing Internet traffic:
• RIP v1
• RIP v2
• OSPF
• IGRP
• EIGRP
• BGP
Notations used: Routing Information Protocol (RIP), Open Shortest Path First (OSPF), Interior Gateway Routing Protocol (IGRP), Enhanced Interior Gateway Routing Protocol (EIGRP), and Border Gateway Protocol (BGP).
One often get confused between a routing protocol and a routed protocol. A routing protocol such as RIP is used to route information packets over the Internet, where as a routed protocol such as IP (or IPX) is the payload (contains data) that get routed from source to the destination.
Routing protocols are primarily distinguished into three types:
• Distance Vector Protocols
• Link State Protocols
• Hybrid Protocols
RIP is an example of distance vector protocol. IS-IS is an example of Hybrid protocol, and OSPF is an example of Link State Protocol.
The table below provides the routing protocol used with different routed protocols:
Routing Protocol Routed Protocol
RIP, OSPF,IS-IS, BGP,EIGRP IP
RIP, NLSP, EIGRP IPX
RTMP, EIGRP AppleTalk
The list of routed, and routing protocols given in the above table is not complete, and given to serve as an example only.
Routing Metric: This is a fundamental measure that routing protocols use for determining appropriate route to deliver packets. Each routing protocol uses its own measure of metric, and a sample of routing metrics used by different routing protocols is given below:
Routing Protocol Metric
RIPv2 Hop count
EIGRP Bandwidth, Delay, Load, Reliability, and MTU
OSPF Cost (Higher bandwidth indicates lower cost)
IS-IS Cost
The best route in RIP is determined by counting the number of hops required to reach the destination. A lower hop count route is always preferred over a higher hop count route. One disadvantage of using hop count as metric is that if there is a route with one additional hop, but with significantly higher bandwidth, the route with smaller bandwidth is taken. This is illustrated in the figure below:
The RIP routed packets take the path through 56KBPS link since the destination can be reached in one hop. Though, the alternative provides a minimum bandwidth of 1MBPS (though using two links of 1MBPS, and 2MBPS each), it represents 2 hops and not preferred by the RIP protocol.
Link State vs. Distance Vector
Distance Vector routing protocols usually send their entire routing table to their nearest neighbors at regular intervals. A router that receives several such routing tables filter the routes and arrive at its own and retransmits it to its neighbouring routers. There will some period of time where different routers hold non-optimized routes initially. After some time, known as convergence time, a final routing table is arrived at by all the routers. A faster convergence time results in a stable network.
RIP, as mentioned earlier uses hop count as the metric for computing a route to a given destination. Other Distance Vector routing protocols, such as IGRP, improve on this by using hop count, bandwidth, current load, cost, and reliability to determine the best path.
Link State routing protocols usually send only the routing changes to every other router within their area. Unlike Distance Vector, routers using Link State routing protocols maintain a picture of the entire network. A router can use this network wide information to determine the best route for traffic.
Example Question:
What is true about IP routing?
A. The frame changes at each hop
B. The source IP address changes at each hop
C. The destination IP address changes at each hop
D. The hardware interface addresses remain constant
Correct answer: A
Explanation:
IP Packets are transported from source network to the destination network by what is known as routing. Hop-by-hop routing model is used by the Internet for delivery of packets. At each hop, the destination IP address is examined, the best next hop is determined by the routing protocol (such as RIP, OSPF or BGP) and the packet is forwarded by one more hop through this route. The same process takes place at the next hop. During this process, the logical addresses remain same. In an IP network, the logical addresses are IP addresses. The hardware interface addresses, such as MAC address change with each hop.
OSPF Routing Fundamentals
OSPF stands for Open Shortest Path First.
Definition: OSPF is a routing protocol used to determine the best route for delivering the packets within an IP networks. It was published by the IETF to serve as an Interior Gateway Protocol replacing RIP. The OSPF specification is published as Request For Comments (RFC) 1247.
Note that OSPF is a link-state routing protocol, whereas RIP and IGRP are distance-vector routing protocols. Routers running the distance-vector algorithm send all or a portion of their routing tables in routing-update messages to their neighbors.
OSPF sends link-state advertisements (LSAs) to all other routers within the same area. Information on attached interfaces, metrics used, and other variables is included in OSPF LSAs. OSPF routers use the SPF (Shortest Path First) algorithm to calculate the shortest path to each node. SPF algorithm is also known as Dijkstra algorithm.
Advantages of OSPF
• OSPF is an open standard, not related to any particular vendor.
• OSPF is hierarchical routing protocol, using area 0 (Autonomous System) at the top of the hierarchy.
• OSPF uses Link State Algorithm, and an OSPF network diameter can be much larger than that of RIP.
• OSPF supports Variable Length Subnet Masks (VLSM), resulting in efficient use of networking resources.
• OSPF uses multicasting within areas.
• After initialization, OSPF only sends updates on routing table sections which have changed, it does not send the entire routing table, which in turn conserves network bandwidth.
• Using areas, OSPF networks can be logically segmented to improve administration, and decrease the size of routing tables.
Disadvantages of OSPF:
• OSPF is very processor intensive due to implementation of SPF algorithm. OSPF maintains multiple copies of routing information, increasing the amount of memory needed.
• OSPF is a more complex protocol to implement compared to RIP.
OSPF Networking Hierarchy:
As mentioned earlier, OSPF is a hierarchical routing protocol. It enables better administration and smaller routing tables due to segmentation of entire network into smaller areas. OSPF consists of a backbone (Area 0) network that links all other smaller areas within the hierarchy. The following are the important components of an OSPF network:
• Areas
• Area Border Routers
• Backbone Areas
• AS Boundary Routers
• Stub Areas
• Not-So-Stubby Areas
• Totally Stubby Area
• Transit Areas
ABR: Area Border Router
ASBR: Autonomous System Boundary Router
Areas: An area consists of routers that have been administratively grouped together. Usually, an area as a collection of contiguous IP subnetted networks. Routers that are totally within an area are called internal routers. All interfaces on internal routers are directly connected to networks within the area.
Within an area, all routers have identical topological databases.
Area Border Routers: Routers that belong to more than one area are called area border routers (ABRs). ABRs maintain a separate topological database for each area to which they are connected.
Backbone Area: An OSPF backbone area consists of all routers in area 0, and all area border routers (ABRs). The backbone distributes routing information between different areas.
AS Boundary Routers (ASBRs): Routers that exchange routing information with routers in other Autonomous Systems are called ASBRs. They advertise externally learned routes throughout the AS.
Stub Areas: Stub areas are areas that do not propagate AS external advertisements. By not propagating AS external advertisements, the size of the topological databases is reduced on the internal routers of a stub area. This in turn reduces the processing power and the memory requirements of the internal routers.
Not-So-Stubby Areas (NSSA): An OSPF stub area has no external routes in it. A NSSA allows external routes to be flooded within the area. These routes are then leaked into other areas. This is useful when you have a non-OSPF router connected to an ASBR of a NSSA. The routes are imported, and flooded throughout the area. However, external routes from other areas still do not enter the NSSA.
Totally Stubby Area: Only default summary route is allowed in Totally Stubby Area.
Transit Areas: Transit areas are used to pass traffic from an adjacent area to the backbone. The traffic does not originate in, nor is it destined for, the transit area.
Link State Advertisements (LSAs):
It is important to know different Link State Advertisements (LSAs) offered by OSPF protocol.
Type 1: Router link advertisements generated by each router for each area it belongs to. Type 1 LSAs are flooded to a single area only.
Type 2: Network link advertisements generated by designated routers (DRs) giving the set of routers attached to a particular network. Type 2 LSAs are flooded to the area that contains the network.
Type 3/4: These are summary link advertisements generated by ABRs describing inter-area routes. Type 3 describes routes to networks and is used for summarization. Type 4 describes routes to the ASBR.
Type 5: Generated by the ASBR and provides links external to the Autonomous System (AS). Type 5 LSAs are flooded to all areas except stub areas and totally stubby areas.
Type 6: Group membership link entry generated by multicast OSPF routers.
Type 7: NSSA external routes generated by ASBR. Only flooded to the NSSA. The ABR converts LSA type 7 into LSA type 5 before flooding them into the backbone (area 0).
Area Restriction
Normal None
Stub Type 5 AS-external LSA NOT allowed
NSSA Type 5 AS-external LSAs are NOT allowed, but Type 7 LSAs that convert to Type 5 at the NSSA ABR can traverse
Totally Stubby Type 3, 4 or 5 LSAs are NOT allowed except the default summary route
Cisco IOS An Introduction
Cisco IOS (short for Internetwork Operating System) is the software used on a majority of Cisco Systems routers and switches. IOS consists of routing, switching, internetworking and telecommunications functions in a multitasking operating system.
Cisco IOS has uses command line interface (CLI), and provides a fixed set of multiple-word commands. A Cisco IOS command line interface can be accessed through either a console connection, modem connection, or a telnet session. The set of commands available at any particular level is determined by the "mode" and the privilege level of the current user.
Cisco IOS follows a command hierarchy, with each level offering different set of commands All commands are assigned a privilege level, from 0 to 15, and can only be accessed by users with the necessary privilege. Through the CLI, the commands available to each privilege level can be defined.
Some of the widely used command hierarchy levels are given below:
User EXEC level: This is the level that a connected user is allowed initially. User EXEC allows access to a limited set of basic monitoring commands. A ">" sign denotes User EXEC mode.
Privileged EXEC level: Privileged EXEC level allows access to all router commands including router configuration and management commands. This level is usually password protected for security reasons. A "#"sign denotes privileged EXEC mode.
When a user is connected to a Cisco IOS, a User EXEC prompt appears. Now, the user can enter privileged EXEC mode by typing the password shown as below:
Router> enable
Password: [enable password]
Router# configure terminal
Router(config)#
Global configuration mode: "Global configuration mode" provides commands to change the system's configuration. This is typically represented by "(config)#" sign as shown in the above example.
Interface configuration mode: "Interface configuration mode" provides commands to change the configuration of a specific interface of the router. An interface configuration mode is denoted by "(config-in)#".
A summary of Cisco IOS router command prompt is given below:
Prompt Explanation
Router> User EXEC mode
Router# Privileged EXEC mode
Router(config)# Global configuration mode. # sign indicates this is only accessible at privileged EXEC mode.
Router(config-if)# Interface level configuration mode.
Router(config-router)# Routing engine level within configuration mode.
Router(config-line)# Line level (vty, tty, async) within configuration mode.
Context Sensitive Help
Cisco IOS CLI offers context sensitive help. At any time during an EXEC session, a user can type a question mark (?) to get help.
Two types of context sensitive help are available:
• Word help and
• Command syntax help.
Word help: Word help can be used to obtain a list of commands that begin with a given character string. To use word help, type in the characters in question followed immediately by the question mark (?). The following is an example of word help:
Router# co?
configure connect copy
Command syntax help: Command syntax help can be used to obtain a list of commands, keyword, or argument options that are available starting with the keywords that the user had already entered. To use command syntax help, enter a question mark (?) after hitting a space. The router will then display a list of available command options with
Router# configure ?
memory Configure from NV memory
network Configure from a TFTP network host
terminal Configure from the terminal
Cisco IOS also allows abbreviated commands support. For example, consider the following:
Router#configure terminal
Router(config)#
Router#config term
Router(config)#
Both the above commands to the same job. The IOS correctly interprets the full command words. However, if there is any ambiguity, an error message is generated as below:
Router(config)#c
% Ambiguous command: "c"
Checkout a ccna router simulator available from certexams.com.
Example Question:
What is the command used to add a banner to a Cisco router configuration?
A. add banner
B. banner motd #
C. motd banner #
D. add banner #
Correct answer: B
Explanation:
The banner is displayed whenever anyone logs in to your Cisco router. The syntax is
"banner motd #
MOTD stands for "Message Of The Day".
# symbol signifies the start of the banner message to the router. You will be prompted for the
message to be displayed. You need to enter "#" symbol at the end of the message, signifying
that the msg has ended.
Alternatively, you can enter the banner in the same line as below:
"banner motd # your message here#
note that you need to begin and end the banner with a delimiter (here # sign).
Cisco Access Control Lists
The Cisco Access Control List (ACL) is are used for filtering traffic based on a given filtering criteria on a router or switch interface. Based on the conditions supplied by the ACL, a packet is allowed or blocked from further movement.
Cisco ACLs are available for several types of routed protocols including IP, IPX, AppleTalk, XNS, DECnet, and others. However, we will be discussing ACLs pertaining to TCP/IP protocol only.
ACLs for TCP/IP traffic filtering are primarily divided into two types:
• Standard Access Lists, and
• Extended Access Lists
Standard Access Control Lists: Standard IP ACLs range from 1 to 99. A Standard Access List allows you to permit or deny traffic FROM specific IP addresses. The destination of the packet and the ports involved can be anything.
This is the command syntax format of a standard ACL.
access-list access-list-number {permit|deny}
{host|source source-wildcard|any}
Standard ACL example:
access-list 10 permit 192.168.2.0 0.0.0.255
This list allows traffic from all addresses in the range 192.168.2.0 to 192.168.2.255
Note that when configuring access lists on a router, you must identify each access list uniquely by assigning either a name or a number to the protocol's access list.
There is an implicit deny added to every access list. If you entered the command:
show access-list 10
The output looks like:
access-list 10 permit 192.168.2.0 0.0.0.255
access-list 10 deny any
Extended Access Control Lists: Extended IP ACLs allow you to permit or deny traffic from specific IP addresses to a specific destination IP address and port. It also allows you to have granular control by specifying controls for different types of protocols such as ICMP, TCP, UDP, etc within the ACL statements. Extended IP ACLs range from 100 to 199. In Cisco IOS Software Release 12.0.1, extended ACLs began to use additional numbers (2000 to 2699).
The syntax for IP Extended ACL is given below:
access-list access-list-number {deny | permit} protocol source source-wildcard
destination destination-wildcard [precedence precedence]
Note that the above syntax is simplified, and given for general understanding only.
Extended ACL example:
access-list 110 - Applied to traffic leaving the office (outgoing)
access-list 110 permit tcp 92.128.2.0 0.0.0.255 any eq 80
ACL 110 permits traffic originating from any address on the 92.128.2.0 network. The 'any' statement means that the traffic is allowed to have any destination address with the limitation of going to port 80. The value of 0.0.0.0/255.255.255.255 can be specified as 'any'.
Applying an ACL to a router interface:
After the ACL is defined, it must be applied to the interface (inbound or outbound). The syntax for applying an ACL to a router interface is given below:
interface
ip access-group {number|name} {in|out}
An Access List may be specified by a name or a number. "in" applies the ACL to the inbound traffic, and "out" applies the ACL on the outbound traffic.
Example:
To apply the standard ACL created in the previous example, use the following commands:
Rouer(config)#interface serial 0
Rouer(config-if)#ip access-group 10 out
Example Question:
Which command sequence will allow only traffic from network 185.64.0.0 to enter interface s0?
A. access-list 25 permit 185.64.0.0 255.255.0.0
int s0 ; ip access-list 25 out
B. access-list 25 permit 185.64.0.0 255.255.0.0
int s0 ; ip access-group 25 out
C. access-list 25 permit 185.64.0.0 0.0.255.255
int s0 ; ip access-list 25 in
D. access-list 25 permit 185.64.0.0 0.0.255.255
int s0 ; ip access-group 25 in
Correct answer: D
Explanation:
The correct sequence of commands are:
1. access-list 25 permit 185.64.0.0 0.0.255.255
2. int s0
3. ip access-group 25 in
WAN Protocols
1. Comparison of WAN and LAN technologies
2. Serial Links
1. Synchronous and
2. Asynchronous
3. Framing and WAN Protocols
a. HDLC
b. LAP, LAPB, LAPD
c. PPP, and SLIP
d. ISDN
I. ISDN BRI
II. ISDN PRI
e. Frame Relay
a. Frame Relay Protocol Overview
b. Frame Relay Network Operation
VLAN - Virtual Local Area Networks
Some basic knowledge of LANs, different topologies, and working of Local Area Networks is required to proceed further.
What is a VLAN?
To refresh your memory, a Local Area Network (LAN) is a set of connected devices like computers, hubs, and switches sharing the same pool of logical address space. Normally, a router is required to route packets from one LAN to another LAN. Traditionally, all packets within a LAN are broadcast to all other devices connected to that particular LAN.
As a result, a traditional LAN has several disadvantages as below:
• Usable bandwidth is shared among all the devices connected to the LAN
• ALL devices connected within a LAN can hear ALL the packets irrespective of whether the packet is meant for that device or not. It is possible for some unscrupulous node listening to data packets not meant for that.
• Suppose, your organization has different departments. Using a traditional LAN, when any changes take place within the organization, physical cables and devices need to be moved to reorganize the LAN infrastructure.
• A LAN cannot extend beyond its physical boundary across a WAN as in VLANs.
If you are looking for a simple networked solution for a small office, it may be a good idea to have a traditional LAN setup with a few hubs or switches. However, if you are planning for a large building or campus wide LAN for several individual departments, a VLAN is almost essential.
Virtual LANs (VLANs) can be considered as an intelligent LAN consisting of different physical LAN segments enabling them to communicate with each other as if they were all on the same physical LAN segment.
Benefits of VLAN: Several of the disadvantages of traditional LANs can be eliminated with the implementation of VLANs.
1. Improved Performance: In a traditional LAN, all the hosts within the LAN receive broadcasts, and contend for available bandwidth. As a result, the bandwidth is shared among all the connected devices within the LAN segment. If you are running high-bandwidth consumption applications such as groupware or server forms, a threshold point may easily be reached. After a threshold, the users may find the LAN too slow or un-responsive. With the use of VLAN, you can divide the big LAN into several smaller VLANs. For example, if there are two file servers, each operating at 100Mbps, in a traditional LAN both the servers have to share the LAN bandwidth of 100Mbps. If you put both the servers in separate VLANs, then both have an available bandwidth of 100Mbps each. Here the available bandwidth has been doubled.
2. Functional separation of an institute or a company: It is often required to separate the functional groups within a company or institute. For example, it might be necessary to separate HR department LAN from that of Production LAN. Traditionally, it requires a router to separate two physical LANs. However, you can set up two VLANs, one for Finance, and the other for Production without a router. A switch can route frames from one VLAN to another VLAN. With VLAN's it is easier to place a workgroup together eventhough they are physically in different buildings. In this case Finance VLAN does not forward packets to Production VLAN, providing additional security.
3. Ease of Network Maintenance:
Network maintenance include addition, removal, and changing the network users. With traditional LANs, when ever a User moves, it may be necessary to re-configure the user work station, router, and the servers. Some times, it may also be necessary to lay the cable, or reconfigure hubs and switches. If you are using VLANs, many of these reconfiguration tasks become unnecessary. For example, you can avoid network address configuration on the work station and the corresponding router if you use VLAN. This is because, routing traffic within VLANs doesn't require a router.
However, VLAN's add some administrative complexity, since the administration needs to manage virtual workgroups using VLANs.
4. Reduced Cost
VLANs minimize the network administration by way of reduced maintenance on account of workstation addition/deletion/changes. This in turn reduce the costs associated with LAN maintenance.
5. Security
Using a LAN, all work stations within the LAN get the frames meant for all other work stations within the broadcast domain. Since a VLAN splits the broadcast domain into two or more, it is possible to put work stations sharing sensitive data in one VLAN, and other work station in another VLAN. Of course, if two VLANs are not sufficient, you can split the work stations into as many VLANs as required. VLAN's can also be used to set up firewalls, restrict access, and send any intrusion alerts to the administrator.
Example:
Question: Your network has 100 nodes on a single broadcast domain. You have implemented VLANs and segmented the network to have 2 VLANs of 50 nodes each. The resulting broadcast traffic effectively:
A. Increases two fold
B. Remains same
C. Decreases by half
D. Increases 4 fold
Ans: C
Explanation: By implementing VLANs, the effective broadcast traffic decreases, since VLANs do not forward the broadcast traffic from one VLAN to another.
LANs and VLANs
Traditional LAN segmentation: Using traditional LAN segmentation, all the segments will be in the same broadcast domain. This effectively, reduces the efficiency of the network. A traditional LAN segmentation is shown below.
Figure 1: Traditional LAN Segmentation
VLANs: Using VLANs, the broadcast domain gets divided into the number of VLANs. If there are three VLANs, as shown in the figure, the broadcast domain will be split into three.
Figure 2: Segmentation using VLANs
Logical View: Given below is the logical view of segmentation using VLANs. Note that a router is required to route traffic between VLANs, and each VLAN is in different broadcast domain.
Only a single router is shown for simplicity. One or more routers may be used for routing interVLAN traffic.
Figure 3: Logical View of VLANs
VLAN Types
How a Switch distinguishes between VLANs? This is done by associating the work stations to a specific VLAN using specified format. This is known as VLAN membership. Four prominent VLAN membership methods are by port, MAC address, protocol type, and subnet address. Each of these are discussed below:
1. VLAN membership by Port:
Here, you define which ports of a Switch belong to which VLAN. Any work station connected to a particular port will automatically be assigned that VLAN. For example, in a Switch with eight ports, ports 1-4 may be configured with VLAN 1, and ports 5-8 may be configured with VLAN2.
One of the disadvantages of this method is that it requires Switch port reconfiguration whenever a user (of course, with associated workstation) moves from one place to another. VLANs by port association operates at Layer 1 of the OSI model.
2. VLAN membership by MAC Address:
Here, membership in a VLAN is based on the MAC address of the user workstation. A Switch that participates in VLAN, uses the MAC addresses to assign a VLAN to each workstation. When a workstation moves to another place, the corresponding switch automatically discovers the VLAN association based on the MAC address of the workstation. Since the MAC address is normally inseparable from that of the workstation, this method of VLAN membership is more amenable to workstation moves.
This type of VLAN works at Layer 2 of the OSI model.
3. Membership by Protocol Type:
Layer 2 header contains the protocol type field. You can use this information to decide on the VLAN association. For example, all IP traffic may be associated with VLAN 1 and all IPX traffic may be associated with VLAN 2.
4. Membership by IP Subnet Address
In this type of VLAN association, membership is based on the Layer 3 header. The Switch reads the Layer 3 IP address and associates a VLAN membership. Note that even though the Switch accesses Layer 3 information, it still works at Layer 2 of OSI model only. A VLAN Switch doesn't do any routing based on IP address.
Examples:
IP Subnet VLAN
192.23.160.0 1
192.23.161.0 2
112.18.0.0 3
IP Subnet addresses assignment to different VLAN's.
IP address based VLANs allow user moves. However, it is likely to take more time to forward a packet by a Switch because it has to read Layer 3 information. Hence the latency rates may be relatively more using this type of VLAN membership.
Communication Between VLANs
Communicating within VLANs: There are different protocols available for communicating between VLANs. These encapsulation schemes are also known as VLAN trunking protocols. These protocols are based on Layer 2 of the OSI model.
These are:
1. Inter-Switch Link Protocol (ISL)
2. IEEE 802.10 Protocol
3. IEEE 802.1Q Protocol
4. ATM LANE Protocol
5. ATM LANE Fast Simple Server Replication Protocol (FSSRP)
Inter-Switch Link Protocol (ISL): The ISL protocol is used to interconnect two VLAN-capable Ethernet, Fast Ethernet, or Gigabit Ethernet devices. Here, VLAN information is tagged to the standard Ethernet frame. The packets on the ISL link contain a standard Ethernet, FDDI, or Token Ring frame and the VLAN information associated with that frame. ISL is a Cisco proprietary protocol.
IEEE 802.10 Protocol: This protocol provides connectivity between VLANs. The protocol incorporates authentication and encryption techniques to ensure data confidentiality and integrity. The protocol operates at layer 2 of OSI model, and hence ensures greater efficiency.
IEEE 802.1Q Protocol: This protocol is used to interconnect multiple switches and routers, and for defining VLAN topologies. IEEE 802.1Q is the industry standard for communicating within VLANs.
ATM LANE Emulation Protocol (LANE): Using LANE, you can benefit from the legacy LAN hardware. The LANE protocol operates over traditional LAN, emulating a broadcast environment like IEEE802.3. LANE makes. LANE allows standard LAN drivers like NDIS and ODI to be used. Applications can use normal LAN functions without the underlying complexities of the ATM implementation. Client work stations need LAN Emulation Client for running LANE protocol. The switches or routers also need to support appropriate LANE functionalities.
ATM LANE Fast Simple Server Replication Protocol (FSSRP): Cisco introduced the ATM LANE Fast Simple Server Replication Protocol (FSSRP). FSSRP provides better network redundancy. If a single LANE server is unavailable due to any technical reasons, the LANE client transparently switches over to the next LANE server and BUS.
Example:
Question:
Match the trunking protocols with respective media:
1. Inter Switch Link A. FDDI
2. LANE B. Fast Ethernet
3. 802.10 C. ATM
Choose the correct choice.
A. 1-> C, 2->B, 3->A
B. 1->B, 2->C, 3->A
C. 1->B, 2->A, 3->C
D. 1->A, 2->B, 3->C
Ans: B
Explanation: ISL, 802.1Q are the VLAN trunking protocols associated with Fast Ethernet. The VLAN trunking protocol defined by 802.10 is associated with FDDI. LANE (LAN Emulation) is associated with ATM.
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