32) What is the sequence number in a TCP header used for (在T C P报头中的顺序号的作用
是什么)？
A. Acknowledgments
B. Reordering of the octets received
C. Rejecting duplicate octets
33) Variable sliding windows provide an explicit mechanism for notifying TCP if an intermediate node (for example, a router) becomes congested (在中间节点，例如一个路由器拥
塞的情况下，可变滑动窗口提供了通知T C P的显式机制)。
A. True
B. False
34) Which of the following parameters is not a part of UDP header (下面的哪一个参数不是U D P报头的一部分)？
A. Source port
B. Urgent pointer
C. Checksum
D. Length
E. Destination port
35) When a router has been configured for UDP flooding, the source address might change,but the destination address will not change as the datagram propagates through the network (当一个路由器已经配置为U D P泛洪时，当数据报在网络上传播的过程中，源地址可能改变，但是目的地址不会改变)？
A. True
B. False
36) The spanning-tree algorithm allows (生成树算法允许)：
A. Forwarding of packets with no control
B. Forwarding of broadcasts to an interface which already has received the broadcast
C. Prevention of duplication of forwarding of packets
D. A and B only
37) IP helper addresses are a form of _ _ _ _ _ _ _ _ _ _ _ _ _ _ addressing and require the command specification of _ _ _ _ _ _ _ _ _on every interface receiving broadcasts that need to be forwarded (IP辅助地址是一种什么类型的寻址方法，在每一个接收到需要转发的广播接口上需要什么命令说明)？
A. Static / IP header address
B. Dynamic / IP forward-protocol UDP
C. Dynamic / IP forward-protocol TCP
38) Which of the following protocols provide address resolution (下面的哪一个协议提供了地址解析)？
A. ICMP
B. RARP
C. IP
D. UDP
E. TCP
39) IP is described as an unreliable mechanism because it does not guarantee delivery (IP被认为是不可靠的机制，因为它不保证发送)。
A. True
B. False
40) What does fragmentation in TCP/IP represent (在T C P / I P中的分段代表什么)？
A. Segmenting of datagrams into 53-byte packets for ATM applications
B. Division of larger datagrams into convenient size packets
C. A process that occurs on a router
D. A, B, and C
E. A and C only
F. B and C only
41) Which of the following statements is true of ARP (下面对A R P的陈述中，哪一个是正确的)？
A. It makes a MAC address logically independent of the physical hardware
B. It makes it necessary for the administrator to physically manage the MAC address of each N I C
C. It integrates routing function with the physical and data link layers
D. It routes packets based on destination host, not on destination network
42) A host’s ARP cache is good forever once it has been created (一个主机的A R P高速缓存
一旦创建，则它永远工作良好)。
A. True
B. False
43) ARP is a broadcast protocol, and ARP caching is used because broadcasts are expensive
( A R P是一个广播协议，并且使用了A R P高速缓存，原因是广播太昂贵了)。
A. True
B. False
44) Reverse Address Resolution Protocol (RARP) is termed“r e v e r s e”because (反向地址解析协议( R A R P )中的“反向”的含义是)：
A. It is used by the system that knows its IP address but does not know its MAC address
B. It is used by the system that knows its MAC address but does not know its IP address
C. It is used by the system that knows the destination’s IP address but does not know the destination's MAC address
D. It is used by the system that knows the destination’s MAC address but does not know the destination's IP address
45) Inverse Address Resolution Protocol (InARP) is generally used by (逆向地址解析协议( I n A R P )通常由什么使用)？
A. Broadcast networks
B. Nonbroadcast networks
C. Both broadcast and nonbroadcast networks
46) The PING command makes use of what ICMP parameter (PING命令使用了什么I C M P参数)？
A. Redirect
B. Source quench
C. Echo reply
D. Destination unreachable
47) ICMP Redirect is sent by (ICMP重定向由什么发出)？
A. A host to the gateway
B. A gateway to the host
C. A router to another router
D. A router to a network
