Multicast - ip igmp join-group vs ip igmp static-group

When implementing IGMP in a multicast environment, the ip igmp join-group command is used to cause the interface of a router to join a particular multicast group, and begin receiving multicast traffic.

The ip igmp static-group command is similar but serves a slightly different function.

• ip igmp join-group will cause the interface to actively join a multicast group as a member. That means that the IP address of the interface itself is a receiver of that multicast traffic. The result is an entry in the multicast routing table. The interface is also able to ping the multicast group it has joined.
• ip igmp static-group will cause the interface to enable hardware switching (or fast switching) of that specific group’s traffic without joining the multicast group itself. The result is that the entry appears in the multicast routing table as before, however, you will be unable to ping the multicast group from that interface, since it is not a member.

Note that the ip igmp static-group command is syntax for Cisco IOS. The corresponding command for a Nexus device ip igmp static-oif.

Links:

https://forum.networklessons.com/t/join-group-over-static-oif/26564/2?u=lagapides

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/command/reference/multicast/n5k-mcast-cr/n5k-igmp_cmds_i.html#pgfId-1034808

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/command/reference/multicast/n5k-mcast-cr/n5k-igmp_cmds_i.html#pgfId-1230243

https://packetlife.net/blog/2008/jul/21/two-ways-force-igmp-join/

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus3548/sw/93x/multicast/b-cisco-nexus-3548_switch-nx-os-multicast-routing-configuration-guide-93x/b-cisco-nexus-3548_switch-nx-os-multicast-routing-configuration-guide-93x_chapter_011.html#id_62034