Brocade BigIron RX Series Configuration Guide - Manual (Page 786)

708 BigIron RX Series Configuration Guide
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Configuring MSDP mesh groups
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Configuring MSDP mesh groups
A PIM Sparse domain can have several RPs that are connected to each other to form an MSDP
mesh group. To qualify as a mesh group, the RPs have to be fully meshed; that is, each RP must be
connected to all peer RPs in a domain. (Refer to
Figure 104 .)
A mesh group reduces the forwarding of SA messages within a domain. Instead of having every RP
in a domain forward SA messages to all the RPs within that domain, only one RP forwards the SA
message. Since an MSDP mesh group is fully meshed, peers do not forward SA messages received
in a domain from one member to every member of the group. The RP that originated the SA or the
first RP in a domain that receives the SA message is the only one that can forward the message to
the members of a mesh group. If a mesh-group member receives a SA message from a MSDP peer
that is not a member of the mesh-group, and the SA message passes the RPF check, then the
member forwards the SA message to all members of the mesh-group. An RP can forward an SA
message to any MSRP router as long as that peer is farther away from the originating RP than the
current MSRP router.
Figure 104 shows an example of an MSDP mesh group. In a PIM-SM mesh group the RPs are
configured to be peers of each other. They can also be peers of RPs in other domains.
TABLE 116 MSDP source active cache
This field... Displays...
Total Entry The total number of entries the cache can hold.
Used The number of entries the cache currently contains.
Free The number of additional entries for which the cache has room.
Index The cache entry number.
SourceAddr The IP address of the multicast source.
GroupAddr The IP multicast group to which the source is sending information.
RP The RP through which receivers can access the group traffic from the
source
Age The number of seconds the entry has been in the cache