User guide

Configuring PIM Configuring PIM
page 7-26 OmniSwitch AOS Release 7 Advanced Routing Configuration Guide March 2015
Configuring a C-BSR
You can use the ip pim cbsr command to configure the local router as the candidate-BSR for PIM
domain. For example:
-> ip pim cbsr 50.1.1.1 priority 100 mask-length 4
This command specifies the router to use its local address 50.1.1.1 for advertising it as the candidate-BSR
for that domain, the priority value of the local router as a C-BSR to be 100, and the mask-length that is
advertised in the bootstrap messages as 4. The value of the priority is considered for the selection of C-
BSR for PIM domain. The higher the value, the higher the priority.
Use the no form of this command to remove the local routers’ candidacy as the BSR. For example:
-> no ip pim cbsr 50.1.1.1
Verifying the C-BSR Configuration
Check the C-BSR and information about priority and mask-length using the show ip pim cbsr command
as follows:
-> show ip pim cbsr
CBSR Address = 214.0.0.7,
Status = enabled,
CBSR Priority = 0,
Hash Mask Length = 30,
Elected BSR = False,
Timer = 00h:00m:00s
For more information about these displays, see the “PIM Commands” chapter in the OmniSwitch AOS
Release 7 CLI Reference Guide.
Bootstrap Routers (BSRs)
As described in the “PIM Overview” section, the role of a Bootstrap Router (BSR) is to keep routers in the
network “up to date” on reachable Candidate Rendezvous Points (C-RPs). BSRs are elected from a set of
Candidate Bootstrap Routers (C-BSRs). Refer to page 7-10 for more information on C-BSRs.
Reminder. For correct operation, all PIM-SM routers within a PIM-SM domain must be able to map a
particular multicast group address to the same Rendezvous Point (RP). PIM-SM provides two methods for
group-to-RP mapping. One method is the Bootstrap Router mechanism, which also involves C-RP adver-
tisements, as described in this section; the other method is static RP configuration.
A C-RP periodically sends out messages, known as C-RP advertisements. When a BSR receives one of
these advertisements, the associated C-RP is considered reachable (if a valid route to the network exists).
The BSR then periodically sends an updated list of reachable C-RPs to all neighboring routers in the form
of a Bootstrap message.