ccna interview questions and answers

part - 54 CCNA Interview Questions and Answers

376 Which ISDN specification series deals with Concepts and Terminology?

A.) World Series

B.) I- Series

C.) Q-Series

D.) 911-Series

E.) J-Series

F.) F-Series

Ans B

The 2 most important ISDN specifications are Q & I: Q - Call setup and teardown. I - Concepts and terminology.

377 Which of the following is an example of the Physical Layer?

A.) SQL

B.) IP

C.) LLC

D.) DDP

E.) Ethernet

Ans E

FDDI, Token Ring and Ethernet are all physical layer framing standards.

378 In regards to the ISDN BRI standard, which channel is used for control?

A.) B

B.) D

C.) E

D.) I

E.) Q

Ans B

B is Bearer for Data (2 channels at 64kb each). D is for Control (16kb).

379 Which protocol resolves an IP address to a MAC address?

A.) DHCP

B.) RARP

C.) ARP

D.) NBP

E.) DNS

Ans C

The Address Resolution Protocol (ARP) sends out a broadcast to determine the MAC address from the IP address.

380 Which of the following is an example of the Network Layer?

A.) TCP

B.) IP

C.) SQL

D.) Token Ring

E.) LLC

Ans B

Most protocol suites have different OSI layer protocols within them. At layer 3, IP is for TCP/IP. TCP is layer 4. IPX is for IPX/SPX. SPX is layer 4. DDP is for Appletalk

381 The Internet Control Message Protocol occurs at what layer of the seven layer model?

A.) Physical

B.) Transport

C.) Session

D.) Datalink

E.) Presentation

F.) Network

Ans F

ICMP is used for error handling and testing at layer 3. Ping and traceroute are examples of ICMP.

382 Which of the following are examples of the Session Layer?

A.) IP

B.) Netbios Names

C.) NFS

D.) Token Ring

E.) SQL

F.) TCP

Ans B C E

Session layer examples include Netbios Names, SQL, NFS, X Windows, and RPC.

383 What is the regional telco office called, where the customers local loop terminates?

A.) Demarc

B.) DTE

C.) DCE

D.) CO

E.) CPE

Ans D

The Central Office (CO) is the Telephone Company (Telco) location nearest you.

384 What is the default LMI type for Cisco Routers that are using Frame-Relay?

A.) Gandalf5

B.) Q933A

C.) Cisco

D.) IETF

E.) ARPA

F.) SAP

Ans C

Local Management Interface (LMI) types are Cisco, ANSI, and Q933A.

385 Most routing protocols recognize that it is never useful to send information about a route back out the direction from which the original packet came. This is an example of which routing technology?

A.) Split Horizon

B.) LMI

C.) Triggered Updates

D.) Poison Reverse

E.) SYN, ACK F.) DLCI

Ans A

The golden rule of Split Horizon: Do not send any update packet back out the same interface that it was received or learned from. Poison Reverse is typically used on larger networks, where a more aggressive routing loop solution is required.

386 Which layer of the 7 layer model is responsible for representing the application information between 2 different OS's? For example, converting ASCII to EBCIDIC.

A.) Transport

B.) Application

C.) Physical

D.) Session

E.) Presentation

F.) Network

Ans E

The OSI Presentation layer formats the data, which includes encryption services.

387 Which type of switching reads in the entire frame before forwarding it?

A.) Tabling

B.) Store-and-Forward

C.) Inverse ARP

D.) Fast Forward

E.) Cut-Through

F.) Routing

Ans B

Store-and-Forward is slower, but it checks the frame for errors before forwarding. This can actually help to improve overall network performance on noisy lines.

388 Which OSI Reference Layer is concerned with path determination?

A.) Datalink

B.) Physical

C.) Network

D.) Transport

E.) Session

Ans C

The Network layer is where routing occurs.

389 Which of the following are examples of the Datalink Layer?

A.) LLC

B.) SQL

C.) TCP

D.) Token Ring

E.) IP

Ans A

MAC and LLC are the sublayers of the Datalink layer.


390 What is the standard ISDN term for a non-native analog telephone?

A.) TE1

B.) TA

C.) LE

D.) TE2

E.) ET

Ans D

Terminal Equipment 2 (TE2) does not support native digital ISDN. The analog device will require an external analog to digital converter.

391 Which Distance Vector characteristic can help to speed up convergence?

A.) Triggered Updates.

B.) Split Horizon.

C.) Poison Reverse.

D.) Hold Down timers.

E.) Inverse ARP.

Ans A

Instead of waiting on a pre-set periodic interval (before sending the routing table), DV routing protocols can send triggered updates to immediately notify the neighbor routers. Hold down timers, Poison Reverse, and Split Horizon are features that are used to avoid routing loops.

392 Which type of switching is considered to be 'wire speed?'

A.) Cut-Through

B.) Multiplexed

C.) Inverted

D.) Layer 4

E.) Store and Forward

F.) Layer 3

Ans A

Cut-Through is the fastest mode of switching. Store and Forward reads in the entire frame, confirms the frame is valid, and then forwards the frame onto the wire. Cut-Through only checks the destination header in the frame and immediately forwards the frame onto the wire, without checking the frame to be valid. Layer-3 switching is actually routing.

393 The Datalink layer works with which of the following:

A.) Packets

B.) Bits

C.) Globules

D.) Frames

E.) Segments

Ans D

Physical - bits Datalink - frames Network - packets

394 What is a characteristic of Store and Forward switches?

A.) They forward the frame before it is completely read.

B.) They work at wire speed.

C.) They are the same a Cut-Through switching.

D.) They read the entire frame and check CRC before forwarding.

E.) They decrease latency.

Ans D

Store and Forward switch will not forward fragments. The longer the frame, the longer the delay (latency) before the switch can forward.

395 Station A is transmitting data to station B, and expects an acknowledgment after every 400 bytes. After transmitting data for a while, the two stations determine the line is reliable and change to expecting and acknowledgement every 600 bytes. This is an example of (pick the best answer only):

A.) BECN

B.) Sliding Windows

C.) Poison Reverse

D.) Countdown timers

E.) Split Horizon

F.) Count to infinity

Ans B

A TCP/IP 'window' is the amount of data (number of bytes) that the sending station will transmit before expecting an acknowledgement back. If the stations can change that window size on the fly, that is called a sliding window. This is done to optimize performance.

396 Which device listed below provides clocking for the line?

A.) DCE

B.) CPE

C.) CO

D.) DTE

E.) Demarc

Ans A

The Data Circuit-terminating Equipment (DCE) is responsible for providing the clocking on the wire. HINT: When You see the 'C' in 'DCE', think 'Clocking' t.

397 Which OSI Reference Layer controls application to application communication?

A.) Datalink

B.) Network

C.) Transport

D.) Session

E.) Physical

Ans D

The Session layer controls a conversation between applications. The Transport layer controls communications between hosts.

398 The Datalink Layer is broken down into 2 layers, LLC and MAC. The LLC establishes media independence and what else?

A.) Provides Windowing.

B.) Provides flow control.

C.) Provides SAP's (Service Access Points).

D.) The Datalink layer does not have sublayers.

E.) Provides SAP's (Service Advertising Protocol).

F.) RIP Updates.

Ans B C

OSI layer-2 SAP allows the upper layers to encapsulate multiple layer 3 protocols. IPX SAP is a protocol used to advertise NetWare services every 60 seconds.

399 When a Distance Vector routing protocol detects that a connected network has gone down, it sends out a special routing update packet, telling all directly connected routers that the distance to the dead network is infinity. This is an example of which routing technology?

A.) ICMP.

B.) Only Link State routing protocols have this intelligence.

C.) Triggered updates.

D.) Garrison-4.

E.) Split Horizon.

F.) Poison Reverse.

Ans F

Instead of just removing the route from the routing update, Poison Reverse sets the distance to 'infinity' (for IP RIP this is a hop count of 16). This immediately makes the route invalid for all neighboring routers.

400 Which of the following would be displayed by the command 'SHOW CDP NEIGHBOR DETAIL'?

A.) The incoming/outgoing port.

B.) The hardware platform.

C.) One address per protocol.

D.) Amount of Flash Memory Available

E.) The routers hostname.

F.) The subnet mask, if IP is configured.

Ans A B C E

CDP shows a lot of the same info that 'show version' does locally, but FLASH memory is not part of it. The 'detail' keyword is optional, but even when used, IP subnet mask information is not displayed by CDP for IP interfaces.