3Com S7902E, Configuration Manual

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Configuring C-RP timers globally
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 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 Configuring PIM Common Timers .
Configuring a BSR
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.
Configuring a C-BSR
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.