MSDP Mesh Groups
An MSDP mesh-group is a mechanism for reducing SA (Source-Active) flooding, especially in intra-domain environment. An MSDP mesh-group is a group of MSDP speakers with fully-meshed MSDP connectivity between each other. Any SA messages received from a peer in a mesh-group in NOT forwarded to other peers in the same mesh-group. This reduces SA message flooding and simple peer-RPF flooding.
Semantics-
1. If a member M of mesh-group MESH receives an SA message from a peer also a member of the same mesh-group MESH, M accepts the SA message and forwards to all its peers that are NOT the members of mesh-group MESH. M must NOT forward SA messages to peers of mesh-group MESH.
2. If a member M of mesh-group MESH receives an SA message from a peer not a member of the mesh-group MESH, and the SA message passes the peer-RPF check, then M forwards the SA message to all peers of mesh-group MESH, and to any other MSDP peers.
To configure MSDP mesh-group, use
ip msdp mesh-group <group-name> <peer-ip-address> command from global configuration mode.
Further reading-
1. RFC 3618: MSDP http://www.faqs.org/ftp/rfc/pdf/rfc3618.txt.pdf
2. http://www.cisco.com/en/US/docs/ios/12_0t/12_0t7/feature/guide/msdp.html#wp12255