44
IGMP SNOOPING
IGMP snooping is the process of listening to Internet Group Management Protocol (IGMP) network
traffic. IGMP snooping, as implied by the name, is a feature that allows a network switch to listen to on
the IGMP conversation between hosts and routers. By listening to the conversations between hosts
and routers, the switch maintains a map of links which need IP multicast streams. Multicast streams
may be filtered from the links which do not solicit them. An IGMP-Snooping-disabled layer-2 device will
flood multicast traffic to all the ports in a broadcast domain (or the VLAN equivalent). With IGMP
snooping enabled, known multicast traffic will be forwarded to hosts that have explicitly joined the
group. It provides switches with a mechanism to prune multicast traffic from links that do not contain a
multicast listener (an IGMP client).
There are two tables under this section, Snooping and Multicast Group Info.
SNOOPING
The snooping tab allows you to enable IGMP snooping and the level
To enable the IGMP snooping, do the following
Select enable from the drop down menu. This select the IGMP version that you would like, they are
described below.
In this switch, there is 3 versions of IGMP
Version 1- In this version, multicast packets are permitted, however there is only a message for
Membership query (packet with destination of 244.0.0.1) and Membership Reply (packet sent to IGMP
group for a device to join the group). There is no message that reports when a client has left the group
Version 2 – This version allows for a leave message to be sent when a device leaves the group. This
prevents unnecessary multicast traffic on the network. Also only one device does Querying all other
devices only listen to the reply.
Version 3 – This is the same as Version 2, accept, it adds support for source-specific multicasting (sends
multicast from particular sender to particular group).
To Next Page
Loading...
Need help?
General
