对交换机的描述，正确的是（）

A.单广播域，单冲突域的设备

B.单广播域，多冲突域的设备

C.多广播域，单冲突域的设备

D.多广播域，多冲突域的设备

A.流量很高时

B.断开的链路重建后

C.上层协议要求可靠性极高时

D.未妥善实现冗余拓扑时

路由协议在收到某一邻居发布而来的路由信息后，下述对度量值的正确处理有哪些?()

A.对本路由表中已有的路由项，当发送该路由信息的邻居相同时，只在度量值减少时更新该路由项的度量值

B.对本路由表中已有的路由项，当发送该路由信息的邻居相同时，只要度量值有改变，一定会更新该路由项的度量值

C.对本路由表中已有的路由项，当发送该路由信息的邻居不同时，只要度量值有改变，一定会更新该路由项的度量值

D.对本路由表中没有的路由项，只在度量值少于不可达时增加该路由项

RIP用()作为度量值。

A.管理距离

B.带宽

C.跳数

D.时间

以下哪些字段不能基于扩展的IPACL来比较（）

A.协议

B.源IP地址

C.目的IP地址

D.TOS字节

E.URL

F.用于FTP传输的文件名

A new Ezonexam switch is installed into an existing LAN and a new VTP trunk is set up with an existing switch. Which VLANs will be allowed on this new trunk?

A．All defined VLANs are allowed on the trunk by default.

B．Each VLAN, or VLAN range, that is specified with the switchport mode command.

C．Each VLAN, or VLAN range, that is specified with the vtp domain command.

D．Each VLAN, or VLAN range, that is specified with the vlan database command.

E．None of the above

R1上执行show ip interface brief命令的输出中显示接口S0/0/0状态码为“up”和“down”，那么以下哪种情况可能属实

A.接口当前配置了shutdown命令

B.R1的串行接口两端协议不同

C.R1的串行接口没有安装串行电缆

D.两台路由器的串行链路，只有一端配置了IP地址

OSPF会运行算法以计算当前最佳路由。下列哪些术语会涉及到此算法()

A.SPF

B.DUAL

C.Feasible successor

D.Dijkstrae

E.Good old commonsense

在大型网络中选择OSPF而不选择RIP的原因是（）

A.更快的路由收敛

B.需要更少的路由器内存

C.需要更少的CPU的资源

D.更优的选路，路由无环路

You download a file from an FTP site on the Internet. What is the highest layer in the OSI model used in this FTP operation?

A. Application

B. Presentation

C. Session

D. Transport

E. Internet

F. Data Link

G. Physical

Why would the Ezonexam administrator change the value of the spanning-tree priority of a switch?

A. in order to optimize the path that frames take from source to destination

B. to increase the priority so a designated port will become a root port

C. to increase the BID, so the switch is more likely to become root bridge

D. in order to allow VLANs to be sent from one switch to another across a single link

E. to force a given switch to become an STP server

F. None of the above