第10题： 正在发展的第四代无线通信技术推出了多个标准，下面的选项中不属于4G标准的是（ ）。
A.LTE
B.WiMAXII
C.WCDMA
D.UMB
答案解析与讨论：www.cnitpm.com/st/2344516479.html

第11题：

下面是家庭用户安装ADSL宽带网络时的拓朴结构图，图中左下角的x是（1）设备，为了建立虚拟拨号线路，在用户终端上安装（2）协议。

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

答案解析与讨论：www.cnitpm.com/st/2344620749.html

第12题： 网络系统设计过程中，物理网络设计阶段的仟务是（ ）。
A.依据逻辑网络设计的要求，确定设备的具体物理分布和运行环境
B.分析现有网络和新网络的各类资源分布，掌握网络的状杰
C.根据需求规范和通信规范，实施资源分配和安全规划
D.理解网络应该具有的功能和性能，最终设计出符合用户需求的网络
答案解析与讨论：www.cnitpm.com/st/2344716661.html

第14题： 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

答案解析与讨论：www.cnitpm.com/st/2344912465.html