ccna interview questions and answers

Part - 17 CCNA Interview Questions and Answers

81 Which service takes information from multiple sources and allocates bandwidth on a single media?

A. Time-division Multiplexing (TDM)

B. Signaling System 7 (SS7)

C. X.25

D. Frame relay

Ans A

82 Which three devices can be used to convert the user data from the DTE into a form acceptable to the WAN service's facility?

A. Modem

B. CSU/DSU

C. TA/NT1

D. CO E. SS7

Ans A, B & C A

modem, CSU/DSU (Channel Service Unit/Data Service Unit), or TA/NT1 (Terminal Adapter/Network Termination 1) can be used to convert the user data from the DTE into a form acceptable to the WAN service's facility.

83 What is the juncture at which the CPE ends and the local loop portion of the service begins?

A. Demarc

B. CO

C. Local loop

D. Last-mile

Ans A

The demarcation or demarc is the juncture at which the CPE ends and the local loop portion of the service begins. The CO (Central Office) is the nearest point of presence for the provider's WAN service. The local loop or "last-mile" is the cabling that extends from the demarc into the WAN service provider's central office.

84 You can access three forms of WAN services with Cisco routers. Select the three forms:

A. Switched or relayed services

B. Interface front end to IBM enterprise data center computers

C. Using protocols that connect peer-to-peer devices like HDLC or PPP encapsulation.

D. IPX/SPX E. NetBEUI

Ans: A, B & C

You can access three forms of WAN services with Cisco routers. Switched or relayed services include X.25, Frame Relay, and ISDN. An interface front end to IBM enterprise data center computers includes SDLC. And, you can access the services of WAN providers using protocols that connect peer devices such as HDLC and PPP encapsulation. IPX/SPX and NetBEUI are LAN protocols.

85 Select the fields for the Cisco HDLC protocol:

A. Flag, Address, Control

B. Flag, Address, Control, Protocol, LCP (Code, Identifier, Length, Data), FCS, Flag

C. Flag, Address, Control, Data, FCS, Flag

D. Flag, Address, Control, Proprietary, Data, FCS, Flag

Ans D

The Cisco HDLC frame format is Flag, Address, Control Proprietary, Data, FCS, Flag. The PPP frame format is Flag, Address, Control, Protocol, LCP (Code, Identifier, Length, Data), FCS, Flag. The SDLC and LAPB format is Flag, Address, Control, Data, FCS, Flag.