When an MSDP peer receives the SA from a peer, the MSDP performs an RPF check. The RPF check
ensures that the SA received from the MSDP peer is the closest to the originating RP. An
RPF check prevents SA loops.
Note
This RPF check is different from the multicast routing RPF check.
If the RPF checks pass, then the receiving MSDP enabled router saves the SA
information in the SA foreign cache and makes it available to the local domain. Each
MSDP peer floods the SA information away from the originating RP. The flooding process
is called peer RPF flooding.
