HP MSR2003 Configuration Manual page 92

Figure 32 Information exchange between C-RPs and BSR
Based on the information in the RP-set, all routers in the network can select an RP for a specific multicast
group based on the following rules:
1. The C-RP that is designated to the smallest group range wins.
2. If the C-RPs are designated to the same group ranges, the C-RP with the highest priority wins.
3. If the C-RPs have the same priority, the C-RP with the largest hash value wins. The hash value is
calculated through the hash algorithm.
4. If the C-RPs have the same hash value, the C-RP with the highest IP address wins.
Anycast RP
PIM-SM requires only one active RP to serve each multicast group. If the active RP fails, the multicast traffic
might be interrupted. The Anycast RP mechanism enables redundancy backup among RPs by configuring
multiple RPs with the same IP address. A multicast source registers with the nearest RP or a receiver joins
the nearest RP to implement source information synchronization.
Anycast RP has the following benefits:
• Optimal RP path—A multicast source registers with the nearest RP to build an optimal SPT. A
receiver joins the nearest RP to build an optimal RPT.
Redundancy backup among RPs—When an RP fails, the RP-related sources and receiver-side DRs
•
will register with or join their nearest available RPs. This achieves redundancy backup among RPs.
Anycast RP is implemented in either of the following methods:
Anycast RP through MSDP—In this method, you can configure multiple RPs with the same IP address
•
for one multicast group and configure MSDP peering relationships between them. For more
information about Anycast RP through MSDP, see "Configuring MSDP."
Anycast RP through PIM-SM—In this method, you can configure multiple RPs for one multicast group
•
and add them to an Anycast RP set. This method introduces the following concepts:
Anycast RP set—A set of RPs that are designated to the same multicast group.
Anycast RP member—Each RP in the Anycast RP set.
Anycast RP member address—IP address of each Anycast RP member for communication
among the RP members.
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