第10題： 正在發(fā)展的第四代無線通信技術推出了多個標準，下面的選項中不屬于4G標準的是（ ）。
A.LTE
B.WiMAXII
C.WCDMA
D.UMB
答案解析與討論：m.richmond-chase.com/st/2344516479.html

第11題：

下面是家庭用戶安裝ADSL寬帶網絡時的拓樸結構圖，圖中左下角的x是（1）設備，為了建立虛擬撥號線路，在用戶終端上安裝（2）協議。

（1）A.DSLAM
B.HUB
C.ADSL Modem
D.IP Router
（2）A.ARP
B.HTTP
C.PPTP
D.PPPoE

答案解析與討論：m.richmond-chase.com/st/2344620749.html

第12題： 網絡系統設計過程中，物理網絡設計階段的仟務是（ ）。
A.依據邏輯網絡設計的要求，確定設備的具體物理分布和運行環(huán)境
B.分析現有網絡和新網絡的各類資源分布，掌握網絡的狀杰
C.根據需求規(guī)范和通信規(guī)范，實施資源分配和安全規(guī)劃
D.理解網絡應該具有的功能和性能，最終設計出符合用戶需求的網絡
答案解析與討論：m.richmond-chase.com/st/2344716661.html

第14題： Let us now see how randomization is done when a collision occurs . After a (1), time is divided into discrete slots whose length is equal to the worst-case round-trip propagation time on ether. To accommodate the longest path allowed by Ethernet, the slot time has been set to 512 bit times, or 51.2us.
After the first collision, each station waits either 0 or 1 (2) times before trying again. If two stations collide and each one picks the same random number, they will collide again. After the second collision, each one picks either 0,1,2 or 3 at random and waits that number of slot times. If a third collision occurs (the probability of this happening is 0.25), then the next time the number of slots to wait is chosen at (3) from the interval 0 to 23-1.
In general, after I collisions, a random number between 0 and 2i -1 is chosen, and that number of slots is skipped. However, after ten collisions have been reached, the randomization (4) is frozen at a maximum of 1023 slots. After 16 collisions, the controller throws in the towel and reports failure back to the computer. Further recoveries up to (5) layers.

（1）A.datagram
 B.collision
 C.connection
D.service
（2）A.slot
 B.switch
 C.process
 D.fire
（3）A.rest
 B.random
 C.once
 D.odds
（4）A.unicast
 B.multicast
 C.broadcast
 D.interval
（5）A.local
 B.next
 C.higher
 D.lower

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