Joining a Multicast Group

Joining a Multicast Group
After the main configuration is done on the router to enable multicast, PIM, rendezvous points,
and RP Mapping Agents, the only other major task is enabling hosts to join multicast groups.
Within Cisco IOS, the network administrator has the opportunity to verify functionality and
connectivity before users use the multicast system and applications. You can configure a router
to join any number of IP multicast groups and thus verify functionality.
This is achieved through the ip igmp join-group group_address command. The group_
address is the multicast address of the group you want the router to join. An example follows:
Terry_3640(config)#interface FastEthernet4/0
Terry_3640(config-if)#ip igmp join-group 224.2.127.254
Terry_3640(config-if)#^Z
Terry_3640#
This tells the router to become a member of the 224.2.127.254 multicast group. Joining a
group facilitates troubleshooting multicast connectivity issues as well.