CCNA考试试题.doc

CCNA考试试题
QUESTION 1
What are two reasons that work administrator would use access lists (Choose two.)
A. to control vty access into a router
B. to control broadcast traffic through a router
C. to filter traffic as it passes through a router
D. to filter traffic that originates from the router
E. to replace passwords as a line of defense against security incursions
Answer: A, C
解答:
问题:网络管理员使用访问控制列表的两个原因
A是一种应用,到你的电脑 D这个答案可能有些疑惑,它的意思是过滤掉源自于路由器的流量,但
是事实上是,我们的访问控制列表不能过滤掉路由器自己产生的流量,只能过滤穿越它的流量,正如C答案说的那
样:
QUESTION 2
A default Frame Relay WAN is classified as what type of work
A. point-to-point
B. broadcast multi-access
C. nonbroadcast multi-access
D. nonbroadcast multipoint
E. broadcast point-to-multipoint
Answer: C
解答:
问题:帧中继默认情况下被定义为哪种类型的物理网络物理网络基本有三种类型:
1点到点
2MA
3NBMA
帧中继默认就是NBMA,也就是nonbroadcast multi-access前面几个字母的缩写
NBMA与MA的区别就是NBMA 没有广播能力(没有以太网那样的广播地址)
QUESTION 3
A single access point has been configured and installed in the center of a square office. A few wireless users are
experiencing slow performance and drops while most users are operating at peak efficiency. What are three likely causes of this
problem (Choose three.)
A. mismatched TKIP encryption
B. null SSID
C. cordless phones
D. mismatched SSID E. metal file s
F. antenna type or direction
Answer: C, E, F
解答:
问题:,
发这个问题的三种最有可能的原因是
考点:无线一些基本常识
分析:
A. 不匹配的TKIP加密
TKIP技术通过提供一种增强型WEP加密引擎,
(原有WEP只提供了24位初始化向量).
如果加密出了问题,那么就根本连接不上,而不会出现性能下降的问题.
B. SSID(Service Set Identifier)
也可以写为ESSID,用来区分不同的网络,最多可以有32个字符,无线网卡设置了不同的SSID就可以进入不同网
络,SSID通常由AP广播出来,通过XP自带的扫描功能可以相看当前区域内的
SSID,,SSID就是一个局域网的名称,只有设置为名称相
同SSID的值的电脑才能互相通信. 如果是空的ssid,那么也会出现不能联网的情况,而不会出现什么性能问题
C. 无绳电话,这个有可能对一些无线网卡产生一定的干扰
D. 不选的理由与B一样
E. 金属文件柜,也能产生一定的屏蔽
F. 天线的类型和方向
QUESTION 4
Refer to the exhibit.
How many broadcast domains exist