Verifying the status of MSDP-PIM
When MSDP receives a new (S,G) pair from the RP as part of an SA message, if PIM has subscribers for this group, then MSDP sends the (S,G) pair to the PIM. The multicast (S,G) tree is then built as a common PIM SPT-tree towards the source.
For more information, refer to Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised), RFC 4601 at https://tools.ietf.org/html/rfc4601.
The following example shows how to check the status of an (S,G) pair:
Verifying the status of an (S,G) pair using show ip pim mroute
vyatta@R1:~$ show ip pim mroute
Multicast Routing Table:
Flags: D - Dense, S - Sparse, C - Connected, P - Pruned, s - SSM group
R - RP-bit set, F - Register flag, T - SPT-bit set, J - Joined to SPT
M - Learned from MSDP, A - Candidate for advertising by MSDP
Timers: uptime, expires
Outgoing interface flags: A - Assert winner
Interface state: Interface, Next-Hop, State
(*, 226.0.100.2) , uptime: 00:00:04, expires: 0 secs, RP: 10.48.0.4, flags: SC
(10.57.0.7, 226.0.100.2), uptime: 00:00:04, expires: 206 secs, flags: SCJTM