Command:

ip igmp join-group


Mode:

Router(config)#


Syntax:

ip igmp join-group group-address

no ip igmp join-group group-address


Syntax Description:

group-address

Address of the multicast group. This is a multicast IP address in four-part, dotted notation.


Command Description:

To have the router join a multicast group, use the ip igmp join-group interface configuration command. To cancel membership in a multicast group, use the no form of this command.

IP packets that are addressed to the group address are passed to the IP client process in the Cisco IOS software.

If all the multicast-capable routers and access servers that you administer are members of a multicast group, pinging that group causes all routers to respond. This can be a useful administrative and debugging tool.

Another reason to have a router join a multicast group is when other hosts on the network have a bug in IGRP that prevents them from correctly answering IGMP queries. Having the router join the multicast group causes upstream routers to maintain multicast routing table information for that group and keep the paths for that group active.


Example:

In the following example, the router joins multicast group 225.2.2.2:

Router(config)#ip igmp join-group 225.2.2.2

Misconceptions:
None

Related Commands:
ping

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