PLANET XGS3-24040 - Manual (Page 400)

Chapter 43 Ipv4 Multicast Protocol
43-54
43.11.3 IGMP Proxy Examples
Example 1: IGMP Proxy function.
Figure 1-12 IGMP Proxy Topology Diagram
As it is show in the figure above, the switch functions as IGMP Proxy in a network of topology of tree, the
switch aggregates the multicast dataflow from upstream port and redistributes them to the downstream ports,
while the IGMP membership reports flow from downstream ports to upstream ports. Three IGMP Proxy
enabled switches which are connected in tree topology, respectively have one port connected to multicast
routers, and no less than one ports connected to hosts or upstream ports from other IGMP Proxy enabled
switches.
The configuration steps are listed below:
Switch#config
Switch(config)#ip igmp proxy
Switch(Config)#interface vlan 1
Switch(Config-if-Vlan1)#ip igmp proxy upstream
Switch(Config)#interface vlan 2
Switch(Config-if-Vlan2)#ip igmp proxy downstream
Multicast Configuration:
Suppose the multicast server offers some programs through 224.1.1.1. Some hosts subscribe that program at
the edge of the network. The IGMP multicast members report themselves to the downstream ports of IGMP
Proxy enabled Switch 2 and Switch 3. Switch 2 and Switch 3 then aggregate the group membership
information and send them through the upstream ports. Switch 1 finally forward these membership
information to the multicast router when receiving the group membership information through upstream ports,
and deliver the multicast dataflow through downstream ports.
Multicast
Server
Multicast
Router
IGMP PROXY
Switch 2
IGMP PROXY
Switch 1
IGMP PROXY
Switch 3
Multicast
Router