I've come accross an issue that I'm having a difficult time understanding.
I have 2 devices, lets call them R20 and R21, connected via ethernet. OSPF adj between them, pim adj between them, igmp version3 on both, both have multicast-routing and ssm-default.
R20 is advertising it's loopback (20.20.20.20/32) into OSPF.
R20-e1/0----------------e1/0-R21
When R21 configures "ip igmp join-group 232.1.1.1 source 20.20.20.20 (R20's loopback)" on its e1/0 interface, state gets created on R20's mroute table. However, when I use "ip igmp static-group 232.1.1.1 source 20.20.20.20 (R20's loopback)" on the same interface, no state gets created on R21's mroute table.
What I've always thought about static-group is that it uses fast-switching of the group out the interface in which the command is configured. This is unlike "join-group" since join-group will process-switch the traffic and will actually become a member of the group.
What I have NOT been able to figure out is why the join is not being processed on R21 when static-group is used instead of join-group.
I configured another interface on R21 (e1/1). I set up pim/igmpv3 and included it into OSPF. This interface does not have any neighbors (IGP/PIM/etc). I then configured the static-join on this interface...it works. Why does it NOT work when I use static-group on the e1/0 interface that is connected to R20 though? Shouldn't the join get sent the same way as it does with a join-group?
Thanks