Nortel Networks NN47200-503 manual IP multicast propagation with Igmp routing

IGMP snooping 47

"IP multicast propagation with IGMP routing" (page 47)shows how IGMP is used to set up the path between the client and server. As shown in this example, the IGMP host provides an IP Multicast stream to designated routers that forward the IP Multicast stream on their local network only if there is a recipient.

The client/server path is set up as follows:

1.The designated router sends out a host membership query to the subnet and receives host membership reports from end stations on the subnet.

2.The designated routers then set up a path between the IP Multicast stream source and the end stations.

3.Periodically, the router continues to query end stations about whether to continue participation.

4.As long as any client continues to participate, all clients, including non-participating end stations on that subnet, receive the IP Multicast stream.

Note: Although the non-participating end stations can filter the IP Multicast traffic, the IP Multicast traffic still exists on the subnet and consumes bandwidth.

IP Multicast can be optimized in a LAN by using IP Multicast filtering switches, such as the Nortel Ethernet Routing Switch 5500 Series.

As shown in "IP multicast propagation with IGMP routing" (page 47), a non-IP Multicast filtering switch causes IP Multicast traffic to be sent to all segments on the local subnet.

IP multicast propagation with IGMP routing

Nortel Ethernet Routing Switch 5500 Series

Configuration-IP Routing Protocols

NN47200-503 03.01 Standard

5.127 August 2007

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