6211 ●One ofthe main resposibi

题目描述

●One ofthe main resposibilities ofICMP is to report （71). Although technology has produced

●One ofthe main resposibilities ofICMP is to report (71). Although technology has produced increasingly reliable transmission media, errors still exist and must be handled. IP is an (72) protocol. This means that error checking and error control are not a concem ofIP.ICMP was designed, in part, to compensate for this shortcoming. Howerver, ICMP does not _(73) errors, it simply reports them. Error correction is left to the higher-level potocols. Error messages are always sent to the original__(74) because the only information available in the datagram about the route is the source and destination lP addresses. ICMP uses the source IP address to send the error massage to the source ofthe(75) .

(71)

A, numbers

B. functions

C. strings

D. errors

(72)

A. reliable

B. unreliable

C. available

D. unavailable

(73)

A. correct

B. conduct

C. produce

D. connect

(74)

A. user

B. destination

C. source

D. program

(75)

A. datagram

B. frame

C. service

D. protocol

请帮忙给出正确答案和分析，谢谢！