第12题： 下面关于路由器的描述中，正确的是（）。
A.路由器中串口与以太口必须是成对的
B.路由器中串口与以太口的IP地址必须在同一网段
C.路由器的串口之间通常是点对点连接
D.路由器的以太口之间必须是点对点连接
答案解析与讨论：www.cnitpm.com/st/403418680.html

第13题： PGP的功能中不包括（）。
A.邮件压缩
B.发送者身份认证
C.邮件加密
D.邮件完整性认证
答案解析与讨论：www.cnitpm.com/st/40342982.html

第14题： 如果DHCP客户端发现分配的IP地址已经被使用，客户端向服务器发出（）报文，拒绝该IP地址。
A.DHCP Release
B.DHCP Decline
C.DHCP Nack
D.DHCP Renew
答案解析与讨论：www.cnitpm.com/st/4034324114.html

第1题： With circuit switching,a（71）path is established between two stations for communication.Switching and transmission resources within the networkare（72）for the exclusive use of the circuit for the duration of the connection.The connection is（73）：Once it is established，it appears to attached devices as if there were a direct connection.Packet switching was designed to provide a more efficient facility than circuit switching for（74）data traffic.Each packet contains some portion of the user data plus control information needed for proper functioning of the network.A key distinguishing element of packet-switching networks is whether the internal operation is datagram or virtual circuit.With internal virtual circuits,a route is defined between two endpoints and all packets for that virtual circuit follow the（75）route,With internal datagrams,each packet is treated independently,and packets intended for the same destination may follow different routes.
71、A.unique
B.dedicated
C.nondedicated
D.independent
72、A.discarded
B.abandoned
C.reserved
D.broken
73、A.indistinct
B.direct
C.indirect
D.transparent
74、A.casual
B.bursty
C.limited
D.abundant
75、A.same
B.different
C.single
D.multiple
答案解析与讨论：www.cnitpm.com/st/4034512931.html