3Com Switch 8800 Family Configuration Guide

466 CHAPTER 44: PIM-SM CONFIGURATION
Entering the PIM View Refer to “Entering the PIM View” “Entering the PIM View”.
Configuring the Time
Intervals for Ports to
Send Hello Packets
In general, PIM-SM broadcasts Hello packets on the PIM-SM-enabled port
periodically to detect PIM neighbors and determine the designated router (DR).
For details, refer to “Configuring the Time Intervals for Ports to Send Hello
Packets” “Configuring the Time Intervals for Ports to Send Hello Packets”.
Configuring
Candidate-BSRs
In a PIM domain, one or more candidate BSRs should be configured. A BSR
(Bootstrap Router) is elected among candidate BSRs. The BSR takes charge of
collecting and advertising RP information.
The automatic election among candidate BSRs is described as follows:
One interface which has started PIM-SM must be specified when configuring the
router as the candidate BSR.
At first, each candidate BSR considers itself as the BSR of the PIM-SM domain, and
sends Bootstrap message by taking the IP address of the interface as the BSR
address.
When receiving Bootstrap messages from other routers, the candidate BSR will
compare the BSR address of the newly received Bootstrap message with that of
itself. Comparison standards include priority and IP address. The bigger IP address
is considered better when the priority is the same. If the priority of the former is
higher, the candidate BSR will replace its BSR address and stop regarding itself as
the BSR. Otherwise, the candidate BSR will keep its BSR address and continue to
regard itself as the BSR.
Perform the following configuration in PIM view.
Candidate-BSRs should be configured on the routers in the network backbone. By
default, no BSR is set. The default priority is 0.
c
CAUTION: One router can only be configured with one candidate-BSR. When a
candidate-BSR is configured on another interface, it will replace the previous
configuration.
Configuring
Candidate-RPs
In PIM-SM, the shared tree built by multicast routing data is rooted at the RP. There
is a mapping from a multicast group to an RP. A multicast group can be mapped to
only one RP. Different multicast groups can be mapped to the same RP or different
RPs.
Perform the following configuration in PIM view.
Tabl e 457 Configure candidate-BSRs
Operation Command
Configure a candidate-BSR
c-bsr Vlan-interface Vlan-interface-number
hash-mask-len [ priority ]
Remove the candidate-BSR configured undo c-bsr