Cisco CCNA考试七十九题

来源：作者：出处：巧巧读书 2006-07-25 进入讨论组

46. Which of the following is not valid?

A. router>show version
B. router#show running-config

C. router#show startup-config
D. router#show RAM

Answer D.

47. Which of the following are basic

router functions?

A. Packet switching
B. Packet filtering
C. Path determination
D. Rapid convergence

Packets get switched once they are determined by the router where to go.

48. Which of the following is not an interior routing protocol?

A. RIP
B. IGRP
C. OSPF
D. BGP

BGP is an exterior routing protocol designed to communicate

between autonomous systems.

49. Which of the following routing protocols communicate r

outer information by sending the state of it s links to all routers

in it s domain?

A. BGP
B. RIP
C. IGRP
D. OSPF

This is a "link state" routing protocol. RIP and IGRP are distance vector,

and BGP communicates reachability between domains.

50. What is a problem caused by distance vector routing protocols?

A. Split horizon
B. Route Poison
C. Counting to infinity
D. Max hop count
E. Hold down timers

Answers ABDE are counter measures to the counting to infinity problem caused

by distance vector protocols.

51. What router command will display the routing protocol settings configured

on a router?

A. show protocol
B. Show routing protocol
C.Show ip protocol
D. Show running-config

This also displays timers, neighbors, and next update info.

52. What helps mitigate the problems with link state protocols? Choose 2

A. Minimize router resource usage.
B. Coordinate updates
C. Minimum hop counts
D. Distance vectoring

53. Which router commands will enable RIP for 176.18.0.0? Choose 2

A. router rip
B. network 176.18.0.0
C. network rip
D. network rip 176.18.0.0

Router rip enables rip. Answer B enable the router to advertise to other routers

that it is available. You must be in the global configuration prompt.

54. Which of the following is a disadvantage with the link state protocol?

Choose 3

A. hold down counters
B. unsynchronized updates
C. high network bandwidth usage
D. high router resource usage

As link state packets flood the network, high network bandwidth can be a problem.

55. Which of the following exist at the application layer of the TCPIP model?

Choose 3

A. SMTP
B. FTP
C. ICMP
D. RIP
E. IGRP

Answers D and E and routing protocols.

56. Which of the following translate Fully Qualified Domain Names

into IP addresses?

A. Wins
B. DNS
C. SNMP
D. TCP

57. Which of the following translate netbios names?

A. Wins
B. DNS
C. SNMP
D. TCP

Netbios names are the names of the computers specified in the identification tab

in the network neighborhood properties.

58. Which of the following is not done by TCP?

A. Subnetting
B. Error checking
C. Sequencing
D. Flow control

59. What does UDP and TCP have in common? Choose 2

A. flow control
B. error checking
C. checksum
D. provide destination and source port numbers

UDP doesn t check for errors.

60. Which of the following does the network layer do? Choose 2

A. Packet switching
B. Translating
C. Path determination
D. Convert signals to bits