ccna interview questions and answers

Part - 53 CCNA Interview Questions and Answers

351 What are the 2 functions of the Data Link Mac layer?

A.) Handles access to shared media

B.) Manages protocol access to the physical network medium

C.) Provides SAPs for higher level protocols

D.) Allows multiple devices to uniquely identify one another on the data link layer

Ans B D

These are the two primary functions of the MAC layer.

352 Which layer is responsible for coordinating communication between systems?

A.) Application

B.) Network

C.) Session

D.) Transport

E.) Physical

F.) Data Link

Ans C

The Session layer performs the following: Responsible for establishing and maintaining communications channels. In practice, this layer is often combined with the Transport Layer. Dialog control between devices or nodes. Organizes the communication through simplex, half and full duplex modes. Deals with connection establishment, data transfer, and connection release.

353 What is the default CDP broadcast update rate for Cisco routers?

A.) 120 seconds

B.) 60 seconds

C.) 30 seconds

D.) 90 seconds

Ans B

Cisco Discovery Protocol is a proprietary protocol to allow you to access configuration information on other routers and switches with a single command. It uses SNAP at the Data-Link Layer. By default CDP sends out a broadcast every 60 seconds and it holds this information for 180 seconds. CDP is enabled by default.

354 You need to come up with a TCP/IP addressing scheme for your company. How many network IDs must you allow for when you define the subnet mask for the network?

A.) One for each WAN link

B.) One for each router interface

C.) One for each NIC installed in each client

D.) One for each subnet with hosts

E.) One for each host ID

Ans A D

When determining Network Ids, you need to take into account each Subnet and Each WAN link you will have. Add these numbers up and you will find the answer to which Network ID you can use.

355 What is the protocol number for UDP?

A.) 6

B.) 17

C.) 25

D.) 21

Ans B

User Datagram Protocol - UDP is a connectionless oriented transport protocol for use when the upper layers provide error-recovery and reliability. UDP does not sequence data or re-assemble it into any order after transmission. This protocol uses Port 17.

356 What is the default LMI type?

A.) Cisco

B.) ANSI

C.) IETF

D.) Q933a

Ans A

Local Management Interface (LMI) was developed in 1990. LMI messages provide information about the current DLCI values, the global or local significance of the DLCI value, and the status of virtual circuits. There are three types of LMI standards: ANSI - Annex D defined by ANSI standard T1.617 ITU-T (Q.933A) - Annex A defined by Q933A Cisco (default) - LMI defined by the gang of four

357 You have two Cisco routers setup back-to-back in a lab using DTE/DCE cables. To which router would you add the clockrate command?

A.) The serial port on the DCE router

B.) The Ethernet port on the DTE router

C.) The Ethernet port on the DCE router

D.) The serial port on the DTE router

Ans A

In order to connect routers back-to-back, a clock rate must be set on the router with the DCE cable. This will provide the clocking usually performed by a DSU/CSU. It is recommended that a bandwidth statement be added to the interface because some routing protocols, such as IGRP, use this to make routing decisions.

358 How does a switch use store and forward?

A.) By using a Class I repeater in a collision domain

B.) The LAN switch copies the entire frame into its onboard buffers and then looks up the destination address in its forwarding, or switching, table and determines the outgoing interface

C.) By using broadcast addresses as source addresses

D.) The switch waits only for the header to be received before it checks the destination address and starts forwarding the packets

Ans B Store-and-Forward switching copies the entire frame into its buffer and computes the CRC. If a CRC error is detected, the frame is discarded, or if the frame is a runt (less than 64 bytes including the CRC) or a giant (more than 1518 bytes including the CRC). The LAN switch then looks up the destination address in its switching table and determines the outgoing interface. The frame is then forwarded to the outgoing interface. Cisco Catalyst 5000 switches uses the Store-and-Forward method. The problem with Store-and-Forward switching is latency is increased. Latency also varies with the size of the frame. The larger the frame, the more latency associated. This of course is due to the fact that the entire frame is copied into its buffer before being forwarded.

359 Which of the following are valid WAN terms?

A.) DTE

B.) DCE

C.) Demarc

D.) CPE

Ans A B C D

All of the above are valid WAN terms.

360 Which two describe frame tagging?

A.) Examines particular info about each frame

B.) A unique ID placed in the header of each frame as it traverses the switch fabric

C.) A user- assigned ID defined to each frame

D.) The building of filter tables

Ans B C

Frame identification (frame tagging) uniquely assigns a user-defined ID to each frame. This technique was chosen by the IEEE standards group because of its scalability. In this approach, a unique user-defined identifier is placed in the header of each frame as it's forwarded throughout the switch fabric. The identifier is understood and examined by each switch prior to any broadcasts or transmissions to switch ports of other switches, router, or end-station devices. When the frame exits the switch fabric, the switch removes the identifier before the frame is transmitted to the target end-station. The following points summarize frame tagging: Used by Catalyst 3000 and 5000 series switches Specifically developed for multi-VLAN, inter-switch communication Places a unique identifier in the header of each frame Functions at layer 2 Requires little processing or administrative overhead

361 A ISDN BRI circuit can be described as a which of the following?

A.) 3B channels

B.) 2-64Kbps B channels and 1-16Kbps D channel

C.) none of the above

D.) 2-64Kbps B channels and 1-16Kbps C channel

Ans B

There are two types of ISDN Channels : BRI (Basic Rate Interface) - is 2 64Kbps B channels for data and one 16Kbps D channel for link management. PRI (Primary Rate Interface) - is 23Kbps B channels and 1 64Kbps D channel.

362 The two sublayers of the IEEE Data Link Layer are which of the following?

A.) Link and Logical Control

B.) Data Link and LLC

C.) Logical Link Control and Media Access Control

D.) Data Link and MAC

Ans C

Logical Link Control Sublayer - Acts as a managing buffer between the upper layers and the lower layers. Uses Source Service Access Points (SSAPs) and Destination Service Access Points (DSAPs) to help the lower layers talk to the Network Layer. Media Access Control (MAC) -The MAC sublayer manages protocol access to the physical network medium. The IEEE MAC specification defines MAC addresses, which allow multiple devices to uniquely identify one another at the data link layer.

363 The -- terminal no editing -- command will perform what function?

A.) Edit the contents of NVRAM

B.) Allows access to the terminal port

C.) Stops the advanced editing feature

D.) Enable password functions

Ans C The command to disable advanced editing feature is: Router(config)# terminal no editing

364 Which two of the following are valid ways to have multiple encapsulation types on a single interface?

A.) This is not possible

B.) subinterfaces

C.) additional physical interfaces

D.) secondary addresses

Ans B D

Cisco routers do not allow multiple encapsulation types on a single interface. Therefore, it is necessary to create either a Secondary Network, or a Subinterface and assign a new encapsulation type.

365 Which 3 statements describe default encapsulation and LMI type configuration?

A.) There are only four encapsulations and 3 LMI type options

B.) The LMI type config term options

C.) In release 11.3 the LMI type is autosensed

D.) The default LMI is Cisco

E.) IETF encap must be configured unless the connecting routers are both cisco

Ans C D E

The above 3 statements best describe default encapsulation and LMI type configuration for Cisco routers.

366 Which can be true regarding VLANs?

A.) They are created by location

B.) They are created by function

C.) They are created by department

D.) They are created by group

Ans A B C D

A Virtual LAN (VLAN) is a switched network that is logically segmented by communities of interest without regard to the physical location of the users. Each port on the switch can belong to a VLAN. Ports in a VLAN share broadcasts. A VLAN looks like, and is treated like, it's own subnet. The benefits of VLANs are as follows: Simplify moves, adds, and changes Reduce administrative costs Have better control of broadcasts Tighten network security Microsegment with scalability Distribute traffic load Relocate server into secured locations

367 What is true when using DDR?

A.) HDLC is the preferred encapsulation

B.) You must use static routing

C.) You should use dynamic routing

D.) You should use ISDN

Ans B

When using Dial Demand Routing (DDR), static routes must be specified in order to route packets.

368 If you are running Token Ring with Novell IPX routing, which encapsulation should
you use?

A.) SAP

B.) SNAP

C.) 802.5

D.) 802.2

Ans B

Token Ring with Novell IPX routing uses the SNAP protocol, not 802.5.

369 What are the 3 ways routers learn paths to destination networks?

A.) Dynamic

B.) Static

C.) Routing tables

D.) Default

Ans A B D

There are three methods in which routers can learn paths to destination networks, they are: 1) Static - The administrator manually enters the routes. 2) Dynamic - A routing protocol is used. 3) Default - A gateway of last resort is set.

370 Bridges work at what layer of the OSI model?

A.) Data Link

B.) Network

C.) Physical

D.) Application

Ans A

Bridges work at Layer 2 (Data Link) because they examine the MAC address of the packet which they base decisions upon.

371 What is the default switching method for the Cisco 5000 series?

A.) Cut-through

B.) Store-and-splice

C.) Latency

D.) Store-and-forward

Ans D

Store-and-Forward switching copies the entire frame into its buffer and computes the CRC. If a CRC error is detected, the frame is discarded, or if the frame is a runt (less than 64 bytes including the CRC) or a giant (more than 1518 bytes including the CRC). The LAN switch then looks up the destination address in its switching table and determines the outgoing interface. The frame is then forwarded to the outgoing interface. Cisco Catalyst 5000 switches uses the Store-and-Forward method. The problem with Store-and-Forward switching is latency is increased. Latency also varies with the size of the frame. The larger the frame, the more latency associated. This of course is due to the fact that the entire frame is copied into its buffer before being forwarded.

372 The benefits to segmenting with Bridges are which of the following?

A.) Scalability

B.) Datagram filtering

C.) Manageability

D.) Reliability

Ans A C D

Manageability, reliability and scalability are all benefits to segmenting with bridges.

373 What is the administrative distance for IGRP?

A.) 90

B.) 120

C.) 110

D.) 100

Ans D

IGRP is a distance vector routing protocol designed by Cisco. The maximum hop count is 255, and it uses a combination of variables to determine a composite metric. IGRP has an administrative distance of 100.

374 On an ISDN BRI interface, the control channel is the 'D' channel. What is the rate of this channel?

A.) 64 Kbps

B.) 1.544 Mbps

C.) 128 Kbps

D.) 2.048 Mbps

E.) 16 Kbps

Ans E

16K for the D channel (control) 64K for the two B channels (data)

375 MIDI and MPEG are examples of what layer of the OSI seven layer model?

A.) Session

B.) Network

C.) Datalink

D.) Transport

E.) Application

F.) Presentation

Ans F

The OSI Presentation layer includes EBCIDIC, ASCII, PICT, GIF, MIDI, and MPEG. Encryption can also occur at this layer.