Msdp Peer-Rpf Forwarding; Msdp Mesh Groups; Virtualization Support - Cisco Nexus 7000 Series Configuration Manual

Configuring MSDP
When a PIM register message advertises a new source, the MSDP process reencapsulates the message in an
SA message that is immediately forwarded to all MSDP peers.
The SA cache holds the information for all sources learned through SA messages. Caching reduces the join
latency for new receivers of a group because the information for all known groups can be found in the cache.
You can limit the number of cached source entries by configuring the SA limit peer parameter. You can limit
the number of cached source entries for a specific group prefix by configuring the group limit global parameter.
The SA cache is enabled by default and cannot be disabled.
The MSDP software sends SA messages for each group in the SA cache every 60 seconds or at the configured
SA interval global parameter. An entry in the SA cache is removed if an SA message for that source and group
is not received within SA interval plus 3 seconds.

MSDP Peer-RPF Forwarding

MSDP peers forward the SA messages that they receive away from the originating RP. This action is called
peer-RPF flooding. The router examines the BGP or MBGP routing table to determine which peer is the next
hop in the direction of the originating RP of the SA message. This peer is called a reverse path forwarding
(RPF) peer.
If the MSDP peer receives the same SA message from a non-RPF peer in the direction of the originating RP,
it drops the message. Otherwise, it forwards the message to all its MSDP peers.

MSDP Mesh Groups

You can use MSDP mesh groups to reduce the number of SA messages that are generated by peer-RPF
flooding. By configuring a peering relationship between all the routers in a mesh and then configuring a mesh
group of these routers, the SA messages that originate at a peer are sent by that peer to all other peers. SA
messages received by peers in the mesh are not forwarded.
A router can participate in multiple mesh groups. By default, no mesh groups are configured.

Virtualization Support

A virtual device context (VDC) is a logical representation of a set of system resources. Within each VDC,
you can define multiple virtual routing and forwarding (VRF) instances. The MSDP configuration applies to
the VRF selected within the current VDC.
You can use the show commands with a VRF argument to provide a context for the information displayed.
The default VRF is used if no VRF argument is supplied.
For information about configuring VDCs, see the Cisco Nexus 7000 Series NX-OS Virtual Device Context
Configuration Guide.
For information about configuring VRFs, see the Cisco Nexus 7000 Series NX-OS Unicast Routing
Configuration Guide.
Cisco Nexus 7000 Series NX-OS Multicast Routing Configuration Guide
MSDP Peer-RPF Forwarding
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