2008年11月网络工程师考试上午真题【基础知识】-软考吧-您身边的软考专家-www.ruankaoba.com

2008年11月网络工程师考试上午真题【基础知识】

内容：基础知识
时间：150分钟
总分：75分
题数：75题

【69】下面关于网络系统设计原则的说法中，正确的是（69）。

真题详情及解析

【70】下面关于通信子网规划设计的说法中，错误的是（70）。

真题详情及解析

【71-75】the usual way to ensure reliable delivery is to provide the （71）with some feedbackaboutwhat is happening at the other end of the line. typically， the protocol calls for thereceivertosend back special （72） frame bearing positive or negative （73）about the incomingframes.if the sender receives a positive acknowledgement about a frame， it knows the the framehasarrivedsafely. on the other hand， a negative acknowledgement means that something has gone wrong，andtheframe must be transmitted again.
an additional complication comes from the possibility that hardware troubles may causeaframeto （74） completely. in this case， the receiver will not react at all， since it has noanyreasonto react. it should be clear that a protocol in which the sender transmits a frame andthenwaitsfor an acknowledgement， positive or negative， will hang forever if a frame is ever lostdueto，forexample，（75） hardware.

真题详情及解析