第50題： 采用CSMA/CD協(xié)議的基帶總線，其段長為1000m，中間沒有中繼器，數(shù)據(jù)速率為10Mb/s，信號傳播速度為200m/μs，為了保證在發(fā)送期間能夠檢測到?jīng)_突，則該網(wǎng)絡(luò)上的最小幀長應(yīng)為（ ）比特。
A.50
B.100
C.150
D.200
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第51題： 以下屬于萬兆以太網(wǎng)物理層標(biāo)準(zhǔn)的是（ ）。
A.IEEE802.3u
B.IEEE802.3a
C.IEEE802.3e
D.IEEE802.3ae
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第52題： IEEE802.11采用了類似于802.3CSMA/CD協(xié)議，之所以不采用CSMA/CD協(xié)議的原因是（ ）。
A.CSMA/CD協(xié)議的效率更高
B.為了解決隱蔽終端問題
C.CSMA/CD協(xié)議的開銷更大
D.為了引進(jìn)其他業(yè)務(wù)
答案解析與討論：www.jycxcx.com/st/2338218504.html

第54題： 大型局域網(wǎng)通常組織成分層結(jié)構(gòu)（核心層、匯聚層和接入層），以下關(guān)于網(wǎng)絡(luò)核心層的敘述中，正確的是（ ）。
A.為了保障安全性，應(yīng)該以分組進(jìn)行盡可能多的處理
B.將數(shù)據(jù)分組從一個(gè)區(qū)域高速地轉(zhuǎn)發(fā)到另一個(gè)區(qū)域
C.由多臺二、三層交換機(jī)組成
D.提供用戶的訪問控制
答案解析與討論：www.jycxcx.com/st/2338422626.html

第55題： 網(wǎng)絡(luò)設(shè)計(jì)過程包括邏輯網(wǎng)絡(luò)設(shè)計(jì)和物理網(wǎng)絡(luò)設(shè)計(jì)兩個(gè)階段，各個(gè)階段都要產(chǎn)生相應(yīng)的文檔，以下選項(xiàng)中，（1）屬于邏輯網(wǎng)絡(luò)設(shè)計(jì)文檔，（2）屬于物理網(wǎng)絡(luò)設(shè)計(jì)文檔。
（1）A.網(wǎng)絡(luò)IP地址分配方案
B.設(shè)備列表清單
C.集中訪談的信息資料
D.網(wǎng)絡(luò)內(nèi)部的通信流量分布
（2）A.網(wǎng)絡(luò)IP地址分配方案
B.設(shè)備列表清單
C.集中訪談的信息資料
D.網(wǎng)絡(luò)內(nèi)部的通信流量分布
答案解析與討論：www.jycxcx.com/st/2338524187.html

第56題： A transport layer protocol usually has several responsibilities .One is to create a process-to-process communication;UDP uses (1)numbers to accomplish this.Another Responsibility is to provide control mechanisms at the  transpt level.UDP does this task at a very minimal level.There is no flow control mechanism and there Is no(2) for received packet. UDP,however ,does provide error control to some extent.If UDP detects an error in the received packet,it will silently drop it.The transport layer also provides a connection mechanism for the processes.The(3)must be able to send streams of data to the transport layer.It is the responsibility of the transport layer at (4)station to make the connection with the receiver.chop the stream into transportable units,number them,and send them one by one.It is the responsibility of th transorort layer at the receiving end to wait until all the different units  belong to th same process have arrived,check and pass those that are(5) free ,and deliver them to the receiving process as a stream.

(1)A. hop   
B. port    
C. route  
D.packet
(2)A. connection   
B. window   
C. acknowledgement  
D.destination
(3)A. jobs   
B. processes   
C. proarams   
D.users
(4)A. sending   
B. routing    
C. switching  
D.receiving
(5)A. call   
B. state    
C. cost  
D.error

答案解析與討論：www.jycxcx.com/st/233861520.html