How does the professor organize the information that she presents？A．By comparing different

A.[Quidway-interface-vlan1]igmp enable用于使能IGMP协议;

B.[Quidway-vlan1]igmp enable用于使能IGMP协议;

C.[Quidway-interface-vlan1]igmp-snooping enable用于使能IGMP snooping;

D.[Quidway]igmp-snooping enable用于使能IGMP snooping。

A、IGMP Snooping(Internet Group Management Protocol Snooping)是运行在二层以太网交换机上的组播约束机制，用于管理和控制组播组

B、IGMP Snooping运行在链路层

C、没有运行IGMP Snooping时，组播报文将在二层广播

D、以上说法全部错误

A、IGMP Snooping(Internet Group Management Protocol Snooping)是运行在二层以太网交换机上的组播约束机制，用于管理和控制组播组

B、IGMP Snooping运行在链路层

C、没有运行IGMP Snooping时，组播报文将在二层播送

D、以上说法全部错误

A. IGMP snooping and Cisco Group Membership Protocol (CGMP) can be used simultaneously on a switch.

B. IGMP snooping a nd Cisco Group Membership Protocol (CGMP) were developed to help Layer 3 switches make intelligent forwarding decisions on their own.

C. IGMP snooping examines IGMP join/leave messages so that multicast traffic is forwarded only to hosts that sent an IG MP message toward the router.

D. IGMP snooping is an IP multicast constraining mechanism for Layer 2 switches.

E. IGMP snooping is enabled with the ip multicast - routing global configuration command.

A.如果主机发出IGMP离开报文时，交换机将改主机加入到相应的组播表中

B.如果主机发出的IGMP主机报告报文时，交换机将删除与该主机对应的组播表项

C.二层交换机通过不断监听IGMP报文，交换机在二层建立和维护MAC广播地址表

D.没有运行IGMP Snooping时，组播报文将在二层广播，运行IGMP Snooping后，报文将不再二层广播，而是进行二层组播

A.组播不通

B.组播正常，但IGMP Snooping无法正确记录成员端口信息

C.组播正常，IGMP Snooping也可以正确记录组播成员端口信息

D.如果同时启用IGMP Spoofing，可以使IGMP Snooping正常工作

A、igmp Snooping

B、igmp proxy

C、igmp on

D、igmp off

A．减少了二层网络中的广播报文，节约带宽

B．增强了组播信息的安全性

C．为实现每台用户主机的单独计费提供了方便

D．IGMP会消耗二层叫混迹的大量的CPU，不推荐使用