HP VSR1000 Configuration Manual page 86

As shown in
messages) to the BSR. An advertisement message contains the address of the advertising C-RP
and the multicast group range to which it is designated. The BSR collects these advertisement
messages and organizes the C-RP information into an RP-set, which is a database of mappings
between multicast groups and RPs. The BSR encapsulates the RP-set information in the bootstrap
messages (BSMs) and floods the BSMs to the entire PIM-SM domain.
Figure 32 Information exchange between C-RPs and BSR
Based on the information in the RP-set, all routers on the network can select an RP for a specific
multicast group based on the following rules:
The C-RP that is designated to the smallest group range wins.
1.
If the C-RPs are designated to the same group ranges, the C-RP with the highest priority wins.
2.
If the C-RPs have the same priority, the C-RP with the largest hash value wins. The hash value
3.
is calculated through the hash algorithm.
If the C-RPs have the same hash value, the C-RP with the highest IP address wins.
4.
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 closest RP or a receiver joins the closest RP to implement source information synchronization.
Anycast RP has the following benefits:
•
Optimal RP path—A multicast source registers with the closest RP to build an optimal SPT. A
receiver joins the closest RP to build an optimal RPT.
•
Redundancy backup among RPs—When an RP fails, the RP-related sources will register
with the closest available RPs and the receiver-side DRs will join the closest available RPs.
This provides 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.
Figure 32, each C-RP periodically unicasts its advertisement messages (C-RP-Adv
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