multicast / static-groups on redundant edge routers not failing back

[jschweng]

We have a WAN bewteen two sites (x)and (y) where we have pim bidir mutcast routing configured.  Site (A) has the RP for hte Source (239.1.1.1).

Site B has redundant Edge routers (A& B) which connect to a LAN segment running PIM SM.  We have static-group commands on the edge router LAN interfaces which forces the packets received from the RP out to the LAN.

If we fail the WAN interface on Router A, the mroutes transfer over to Router B, and the DF on the LAN side fails over.  Eventually after six minutes all the mroutes on Router A timeout.

Then if we restore Router A's WAN interface.  The MRoutes do not failback to Router A.

if I put static-join commands on the edge routers  LAN interfaces then it does failback all works ok.

What;s teh difference between static-jon and static-group?

does static-group even initiate a join back to the RP or does it just fastswitch the packets it receives?

Is there a CPU hit on the static-join vs. using static-group?

[hbruyere]

Hello,

To answer your question: static-join does like static-group, but also makes the router a receiver for the group, so mcast packets will be sent to the CPU (where they will be dropped since there is no process listening to the stream). So if there are heavy streams, static-join could cause high cpu utilization.

But your problem is a bit weird. I don't see why using static-join vs static-group would influence the DF election. That might require some investigations to be made in a TAC case.

Regards,

Herve