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To enable the BSR to distribute the RP-set information within the PIM-SM domain, C-RPs must 

periodically send C-RP-Adv messages to the BSR. The BSR learns the RP-set information from the 

received messages, and encapsulates its own IP address together with the RP-set information in its 

bootstrap messages. The BSR then floods the bootstrap messages to all PIM routers (224.0.0.13) in 

the network.  

Each C-RP encapsulates a timeout value in its C-RP-Adv messages. Upon receiving a C_RP-Adv 

message, the BSR obtains this timeout value and starts a C-RP timeout timer. If the BSR fails to hear a 

subsequent C-RP-Adv message from the C-RP within the timeout interval, the BSR assumes the C-RP 

to have expired or become unreachable.  

The C-RP timers need to be configured on C-RP routers.  

Follow these steps to configure C-RP timers globally:  

To do... 

Use the command... 

Remarks 

Enter system view 

— 

Enter public instance PIM view 
or VPN instance PIM view 

pim [ vpn-instance 
vpn-instance-name ] 

— 

Configure the C-RP-Adv 
interval  

c-rp advertisement-interval 
interval 

Optional 

60 seconds by default  

Configure C-RP timeout time  

c-rp holdtime interval 

Optional 

150 seconds by default  

 

For the configuration of other timers in PIM-SM, refer to 

. 

 

 

A PIM-SM domain can have only one BSR, but must have at least one C-BSR. Any router can be 

configured as a C-BSR. Elected from C-BSRs, the BSR is responsible for collecting and advertising RP 

information in the PIM-SM domain. 

C-BSRs should be configured on routers in the backbone network. When configuring a router as a 

C-BSR, be sure to specify a PIM-SM-enabled interface on the router. The BSR election process is 

summarized as follows: 

z 

Initially, every C-BSR assumes itself to be the BSR of this PIM-SM domain, and uses its interface 

IP address as the BSR address to send bootstrap messages.  

z 

When a C-BSR receives the bootstrap message of another C-BSR, it first compares its own priority 

with the other C-BSR’s priority carried in message. The C-BSR with a higher priority wins. If there is 

a tie in the priority, the C-BSR with a higher IP address wins. The loser uses the winner’s BSR 

address to replace its own BSR address and no longer assumes itself to be the BSR, while the 

winner retains its own BSR address and continues assuming itself to be the BSR.