Multicast BGP functionality is provided through a separate address family context. A subsequent address family identifier (SAFI) provides information about the type of the network layer reachability information that is carried in the attribute. Multiprotocol BGP unicast uses SAFI 1 messages, and multiprotocol BGP multicast uses SAFI 2 messages. SAFI 1 messages indicate that the routes are only usable for IP unicast, but not IP multicast. Because of this functionality, BGP routes in the IPv6 unicast RIB must be ignored in the IPv6 multicast RPF lookup.
A separate BGP routing table is maintained to configure incongruent policies and topologies (forexample, IPv6 unicast and multicast) by using IPv6 multicast RPF lookup. Multicast RPF lookup is very similar to the IP unicast route lookup. No MRIB is associated with the IPv6 multicast BGP table. However, IPv6 multicast BGP operates on the unicast IPv6 RIB when needed. Multicast BGP does not insert or update routes into the IPv6 unicast RIB. How to Implement IPv6 Multicast Enabling IPv6 Multicast Routing To enable IPv6 multicast routing, perform this procedure: Procedure Implementing IPv6 Multicast How to Implement IPv6 Multicast Command or Action Purpose Step 1 enable Example:
Device> enable Enables privileged EXEC mode. Enter your password if prompted. Step 2 configure terminal Example: Device# configure terminal Enter global configuration mode. Step 3 ipv6 multicast-routing Example: Device(config)# ipv6 multicast-routing Enables multicast routing on all IPv6-enabled interfaces and enables multicast forwarding for PIM and MLD on all enabled interfaces of the switch. Step 4 copy running-config startup-config Example: Device(config)# copy running-config startup-config (Optional) Save your entries in the configuration file. Implementing IPv6 Multicast 9