IGMP snooping manages multicast traffic at Layer 2 by configuring Layer 2 LAN interfaces dynamically to forward multicast traffic only to those interfaces that want to receive it.

• 是通过特殊的多点广播查询和主机来管理网络的多点广播数据流。查询者向其他的主机发送查询。常见的是路由器；查询者和主机通过使用IGMP消息报文来加入或是脱离一个主机组。