HP MSR2003 Configuration Manual page 291

Anycast RP has the following benefits:
• Optimal RP path—An IPv6 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 by using either of the following methods:
Anycast RP through MSDP—In this method, you can configure multiple RPs with the same IP address
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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 IPv6 PIM-SM—In this method, you can configure multiple RPs for one IPv6
•
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 IPv6 multicast group.
Anycast RP member—Each RP in the Anycast RP set.
Anycast RP member address—IPv6 address of each Anycast RP member for communication
among the RP members.
Anycast RP address—IPv6 address of the Anycast RP set for communication within the IPv6
PIM-SM domain. It is also known as RPA.
As shown in Figure
Figure 87 Anycast RP through IPv6 PIM-SM
The following describes how Anycast RP through IPv6 PIM-SM is implemented:
a. RP 1 receives a register message destined to the Anycast RP address (RPA). Because the
message is not from other Anycast RP members (RP 2 or RP 3), RP 1 assumes that the register
message is from the DR. RP 1 changes the source IPv6 address of the register message to its
own IPv6 address and sends the message to the other members (RP 2 and RP 3).
If a router acts as both a DR and an RP, it creates a register message, and then forwards the
message to the other RP members.
b. After receiving the register message, RP 2 and RP 3 find out that the source address of the
register message is an Anycast RP member address. They stop forwarding the message to
other routers.
In Anycast RP implementation, an RP must forward the register message from the DR to other
Anycast RP members to synchronize IPv6 multicast source information.
87, RP 1, RP 2, and RP 3 are members of an Anycast RP set.
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