1. [单选题]把访问权限表应用到路由器端口的命令是：()
A. permit access-list 101 out
B. ip access-group 101 out
C. apply access-list 101 out
D. access-class 101 out
2. [单选题]What is the purpose of the spanning-tree algorithm in a switched LAN?
A. To provide a monitoring mechanism for networks in switched environments.
B. To manage VLANs across multiple switches.
C. To prevent switching loops in networks with redundant switched paths.
D. To segment a network into multiple collision domains.
E. To prevent routing loops in networks.
3. [单选题]OSI七层模型中，数据链路层(data link layer)的数据封装名称为（）
A. 比特
B. 帧
C. 包
D. 段
4. [单选题]RIP路由协议认为“网络不可到达”的跳数是：()
A. 8
B. 16
C. 24
D. 100
5. [单选题]路由器下，由一般用户模式进入特权用户模式的命令是：（）
A. enable
B. config
C. interface
D. router
6. [单选题]PPP工作在OSI的哪一层（）
A. 物理层
B. 数据链路层(data link layer)
C. 网络层
D. 传输层
7. [单选题]IP地址为：192.168.50.70，掩码为：255.255.255.248，则该IP地址所在子网的子网号为（）
A. 192.168.50.32
B. 192.168.80.64
C. 192.168.50.96
D. 192.168.50.71
8. [单选题]某台PC，能ping通路由器，但不能telnet到路由器，可能的原因是（）
A. PC的IP地址设置错误
B. 路由器端口IP设置错误
C. 路由器端口处于关闭状态
D. telnet密码未设置
9. [多选题]Regarding the extended ping command; which of the statements below are true?(Select all valid answer choices)
A. The extended ping command is supported from user EXEC mode.
B. The extended ping command is available from privileged EXEC mode.
C. With the extended ping command you can specify the TCP and UDP port to be pinged.
D. With the extended ping command you can specify the timeout value.
E. With the extended ping command you can specify the datagram size.
10. [单选题]TCP23是（）协议端口号；UDP69是（）端口号；TCP80是（）端口号。
A. TELNET FTP HTTP
B. FTPT FTP HTTP
C. TELNET TFTP HTTP
D. TELNET DNS HTTP
