Configuring the Rendezvous Point

You can configure the rendezvous point (RP) manually or let it be auto−discovered. To configure the RP manually, you have to configure the routers that have either the sender of the multicast traffic or the receiver of the multicast traffic connected to its segment. The RP router can be any router on the network and does not need to know that it is the rendezvous point:

Router(config−if) ip pim rp−address [ip address]

To configure Auto−RP, you set up the RP router to send an rp−announce message:

Router(config)# ip pim send−rp−announce [interface] scope 11 group−list 1 Router(config)# access−list 1 permit 239.0.0.0 0.255.255.255

You can use any interface on the router, including the loop−back interface, as the IP address of the administrative group (just make sure all the routers know the route to that IP address).

Adding a Router to a Multicast Group

This feature lets the router accept and forward multicast traffic. You can use this command if the host on the segment cannot report its group memberships:

Router(config−if)# ip igmp join−group 225.01.02.112

Configuring a Router to Be a Static Multicast Group Member

This command will forward the desired multicast group to the specified segment of the network. Perform it on the interface connected to that segment:

Router(config−if)# ip igmp static−group 225.01.02.112

Restricting Access to a Multicast Group

Use this command when you want to restrict certain portions of the network from accessing multicast traffic:

Router(config−if)# ip igmp access−group [access−list−number]

Changing the IGMP Version

Cisco routers use IGMP version 2 by default. You must change the version of IGMP if you have version 1 equipment on the subnet, because all systems on the subnet must use the same version of IGMP. The router will not automatically change to version 1 if it detects version 1 equipment. Use the following command to change to version 1:

Router(config−if)# ip igmp version 1

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