Non-CongruentUni-Multicast Routes
There might be the need to differentiate unicast and multicast routes at AS boundaries
- E.g., for policy reasons (peering agreements)
- And, PIM is limited to a single administrative domain
MBGP (Multicast extension to BGP-4)
- define MBGP peers using the same knobs of the “normal” BGP (route-maps, peer-groups, etc)
- networks can be selectively inserted into the MBGP unicast routing table, the multicast routing table, or both
- an MBGP peer can be sent unicast traffic only, multicast traffic only, or both
- MBGP can be useful when you have non-congruent uni-multicast routers, but also when they are congruent and you want to keep 2 different routing tables