In the previous port, we reviewed MSDP, Multicast Source Discovery Protocol (MSDP) is the key protocol that makes Anycast RP possible. The Anycast RP uses MSDP for redundancy and failover between RPs in Protocol Independent Multicast sparse mode (PIM-SM) networks. Rendezvous Points can share one IP address (same-address allocated to their loopback) and load-balance multicast traffic within the network. Data is routed to the nearest and the best destination as viewed by the routing topology. RP can be configured statically by “ip pim rp-address” command or dynamically using Auto-RP or PIMv2 (BSR).
Note: adding a new loopback can change your OSPF/BGP/LDP Router-ID, it’s always recommended to hard-code your router-ID by router-id command.
Example:
Multicast path is: R7-> R5 –> R3 –> R1 –> R2 –> R4 –> R6 –> R8
R1:
interface Loopback0
ip address 10.10.1.1 255.255.255.255
ip pim sparse-mode
!
interface Loopback69
ip address 10.10.69.69 255.255.255.255
ip pim sparse-mode
!
interface FastEthernet0/0
ip pim sparse-mode
!
interface ATM2/0
ip pim sparse-mode
!
!
router ospf 1
router-id 10.10.1.1
network 10.10.0.0 0.0.255.255 area 0
!
ip pim autorp listener
ip pim send-rp-announce Loopback69 scope 255
ip pim send-rp-discovery Loopback69 scope 255
ip msdp peer 10.10.12.2 connect-source FastEthernet0/0
!
R2:
interface Loopback0
ip address 10.10.2.2 255.255.255.255
ip pim sparse-mode
!
interface Loopback69
ip address 10.10.69.69 255.255.255.255
ip pim sparse-mode
!
interface Ethernet0/0
ip pim sparse-mode
!
interface Serial1/0
ip pim sparse-mode
!
router ospf 1
router-id 10.10.2.2
network 10.10.0.0 0.0.255.255 area 0
!
ip pim bsr-candidate Loopback69 0
ip pim rp-candidate Loopback69
ip msdp peer 10.10.12.1 connect-source Ethernet0/0
!
R2#sh ip msdp sa-cache
MSDP Source-Active Cache – 1 entries
(10.10.57.7, 224.100.100.100), RP 10.10.69.69,
AS ?,00:00:15/00:05:44, Peer 10.10.12.1
R5#sh ip pim rp mapping
PIM Group-to-RP Mappings
Group(s) 224.0.0.0/4
RP 10.10.69.69 (?), v2v1
Info source: 10.10.69.69 (?), elected via Auto-RP
R6#sh ip pim rp mapping
PIM Group-to-RP Mappings
Group(s) 224.0.0.0/4
RP 10.10.69.69 (?), v2
Info source: 10.10.69.69 (?), via bootstrap
For more information:
http://www.cisco.com/en/US/docs/ios/solutions_docs/
ip_multicast/White_papers/anycast.html
