Administrator Guide
Figure 85. MSDP SA Message Format
Topics:
• Anycast RP
• Implementation Information
• Configure Multicast Source Discovery Protocol
• Enable MSDP
• Manage the Source-Active Cache
• Accept Source-Active Messages that Fail the RFP Check
• Specifying Source-Active Messages
• Limiting the Source-Active Messages from a Peer
• Preventing MSDP from Caching a Local Source
• Preventing MSDP from Caching a Remote Source
• Preventing MSDP from Advertising a Local Source
• Logging Changes in Peership States
• Terminating a Peership
• Clearing Peer Statistics
• Debugging MSDP
• MSDP with Anycast RP
• Configuring Anycast RP
• MSDP Sample Configurations
Anycast RP
Using MSDP, anycast RP provides load sharing and redundancy in PIM-SM networks. Anycast RP allows two or more
rendezvous points (RPs) to share the load for source registration and the ability to act as hot backup routers for each other.
Anycast RP allows you to configure two or more RPs with the same IP address on Loopback interfaces. The Anycast RP
Loopback address are configured with a 32-bit mask, making it a host address. All downstream routers are configured to know
that the Anycast RP Loopback address is the IP address of their local RP. IP routing automatically selects the closest RP for
each source and receiver. Assuming that the sources are evenly spaced around the network, an equal number of sources
register with each RP. Consequently, all the RPs in the network share the process of registering the sources equally. Because a
source may register with one RP and receivers may join to a different RP, a method is needed for the RPs to exchange
information about active sources. This information exchange is done with MSDP.
With Anycast RP, all the RPs are configured to be MSDP peers of each other. When a source registers with one RP, an SA
message is sent to the other RPs informing them that there is an active source for a particular multicast group. The result is
that each RP is aware of the active sources in the area of the other RPs. If any of the RPs fail, IP routing converges and one of
the RPs becomes the active RP in more than one area. New sources register with the backup RP. Receivers join toward the new
RP and connectivity is maintained.
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Multicast Source Discovery Protocol (MSDP)