HP A6600 Configuration Manual page 178

Although RP 4 and RP 5 are in the same AS (AS 3) and both are MSDP peers of RP 6, because RP 5 has
a higher IP address, RP 6 accepts only the SA message from RP 5.
When RP 7 receives the SA message from RP 6
Because the SA message is from a static RPF peer (RP 6), RP 7 accepts the SA message and forwards it to
other peer (RP 8).
When RP 8 receives the SA message from RP 7
A BGP or MBGP route exists between two MSDP peers in different ASs. Because the SA message is from
an MSDP peer (RP 7) in a different AS, and the MSDP peer is the next hop on the BGP or MBGP route to
the source-side RP, RP 8 accepts the message and forwards it to its other peer (RP 9).
When RP 9 receives the SA message from RP 8
Because RP 9 has only one MSDP peer, RP 9 accepts the SA message.
SA messages from paths other than those described previously will not be accepted or forwarded by
MSDP peers.
Implementing intra-domain Anycast RP by leveraging MSDP peers
Anycast RP refers to an application that enables load balancing and redundancy backup between two or
more RPs within a PIM-SM domain by configuring the same IP address for, and establishing MSDP
peering relationships between, these RPs.
As shown in
group G, and Receiver is a member of the multicast group. To implement Anycast RP, configure the same
IP address (known as Anycast RP address, typically a private address) on Router A and Router B,
configure these interfaces as C-RPs, and establish an MSDP peering relationship between Router A and
Router B.
Usually an Anycast RP address is configured on a logic interface, like a loopback interface.
Figure 53 Typical network diagram of Anycast RP
The work process of Anycast RP is as follows:
The multicast source registers with the nearest RP. In this example, Source registers with RP 1, with its
1.
multicast data encapsulated in the register message. When the register message arrives at RP 1, RP
1 de-encapsulates the message.
Receivers send join messages to the nearest RP to join in the RPT rooted as this RP. In this example,
2.
Receiver joins the RPT rooted at RP 2.
Figure 53, within a PIM-SM domain, a multicast source sends multicast data to multicast
RP 1
Router A
Source
PIM-SM
MSDP peers
SA message
RP 2
Router B
Receiver
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