R3303-HP HSR6800 Routers IP Multicast Configuration Guide
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Configuring C-RP timers globally
To enable the BSR to distribute the RP-set information within the BIDIR-PIM 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 in the network.
Each C-RP encapsulates a timeout value in its C-RP-Adv messages. After 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.
To configure C-RP timers globally:
Ste
p
Command
Remarks
1. Enter system view.
system-view N/A
2. Enter public network PIM view
or VPN instance PIM view.
pim [ vpn-instance
vpn-instance-name ]
N/A
3. Configure the C-RP-Adv
interval.
c-rp advertisement-interval interval
Optional.
60 seconds by default.
4. Configure C-RP timeout timer.
c-rp holdtime interval
Optional.
150 seconds by default.
For more information about the configuration of other timers in BIDIR-PIM, see "Configuring common PIM
timers."
Configuring a BSR
A BIDIR-PIM 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 collects and advertises RP information in the
BIDIR-PIM domain.
Configuring a C-BSR
C-BSRs must 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 as follows:
• Initially, every C-BSR assumes itself to be the BSR of the BIDIR-PIM domain, and uses its interface IP
address as the BSR address to send bootstrap messages.
• 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 a tie
exists 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, and the winner
retains its own BSR address and continues assuming itself to be the BSR.
Configuring a legal range of BSR addresses enables filtering of bootstrap messages based on the
address range, therefore preventing a maliciously configured host from masquerading as a BSR. The
same configuration must be made on all routers in the BIDIR-PIM domain. The following are typical BSR
spoofing cases and the corresponding preventive measures: