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.