ASM SSM multicast in MPLS domain

[gautamanish]

in our mpls network we have ssm deployed for multicast, but for some old reason there is a static RP also defined on each box and as per my understanding it is not required incase of SSM. we are planning to remove the RP entry but after removing it from some of the boxes some of the multicast tunnels went down. Can someone provide some info if ASM and SSM both are enabled, is there a preference which would be used or any other problems that are due to arise because of both models deployed.

[Giuseppe Larosa · Accepted solution]

Hello Gautam,

usually SSM is deployed for a subset of multicast address space.

you need to verify if there are multicast groups that are out of this SSM subset, for those groups to run in PIM SM an RP is required.

Hope to help

Giuseppe

[gautamanish]

thanks mate, i understand that SSM is used as subset of multicast addresses but if i have defined a SSM range in my  network and also defined a RP for the same range, what is going to be the affect

[guan]

well, then it should not effect any SSM operation, because ssm is coupled with IGMPv3 which knows the source before hand, pim join will go directly to the source bypassing any RP