Cisco XR 12000 Series Configuration Manual page 73

Implementing Multicast Routing on Cisco IOS XR Software Cisco ASR 9000 Series Routers
In Anycast RP, two or more RPs are configured with the same IP address on loopback interfaces.
Configure the Anycast RP loopback address with a 32-bit mask, making it a host address. Configure all
downstream routers to "know" that the Anycast RP loopback address is the IP address of the local RP.
IP routing automatically selects the topologically closest RP for each source and receiver.
As 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.
In Anycast RP, all the RPs are configured to be MSDP peers of each other. When a source registers with
one RP, a Source-Active (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 knows about the active sources in the
area of the other RPs. If any of the RPs fails, IP routing converges and one of the RPs becomes the active
RP in more than one area. New sources register with the backup RP, and receivers join the new RP.
Note that the RP is usually needed only to start new sessions with sources and receivers. The RP
facilitates the shared tree so that sources and receivers can directly establish a multicast data flow. If a
multicast data flow is already directly established between a source and the receiver, an RP failure does
not affect that session. Anycast RP ensures that new sessions with sources and receivers can begin at any
time.
The following Anycast RP example configures Router A and Router B as Anycast RPs. The Anycast RP
IP address assignment is 10.0.0.1.
Router A
interface loopback 0
ipv4 address 10.0.0.1/32
no shutdown
interface loopback 1
ipv4 address 10.2.0.1/32
no shutdown
multicast-routing
interfaces all enable
router pim
rp-address 10.0.0.1
router msdp
connect-source loopback 1
peer 10.2.0.2
Router B
interface loopback 0
ipv4 address 10.0.0.1/32
no shutdown
interface loopback 1
ipv4 address 10.2.0.2/32
no shutdown
multicast-routing
interfaces all enable
router pim
rp-address 10.0.0.1
router msdp
connect-source loopback 1
peer 10.2.0.1
Apply the following configuration to all network routers:
multicast-routing
router pim
rp-address 10.0.0.1
OL-
Configuration Examples for Implementing Multicast Routing on Cisco IOS XR Software
Multicast Configuration Guide
MCC-65