3Com 7700 Configuration Manual page 189

Using undo pim command, you can clear the configuration in PIM view, and back
to system view.
Configure 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 new BSR address is better, the candidate BSR will replace its BSR address.
Otherwise, the candidate BSR will keep its BSR address and continue to regard
itself as the BSR.
Perform the following configuration in PIM view.
Table 27 Configure Candidate-BSRs
Operation
Configure a candidate-BSR
Remove the candidate-BSR
configured
Candidate-BSRs should be configured on the routers in the network backbone. By
default, no BSR is set. The default priority is 0.
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.
Configure Candidate-RPs
In PIM-SM, the shared tree built by the 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 an RP. Different groups can be mapped to one RP.
Perform the following configuration in PIM view.
Table 28 Configure Candidate-RPs
Operation
Configure a candidate-RP
Remove the candidate-RP
configured
If the range of the served multicast group is not specified, the RP will serve all
multicast groups. Otherwise, the range of the served multicast group is the
PIM-SM Configuration
Command
c-bsr interface-type interface-number hash-mask-len [
priority ]
undo c-bsr
Command
c-rp interface-type interface-number [ group-policy
acl-number ]
undo c-rp interface-type interface-number
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