Concept Guide

Some routers within the domain are congured to be C-RPs. Other routers are congured to be Bootstrap Router candidates (C-BSRs);
one router is elected the BSR for the domain and the BSR is responsible for forwarding BSM containing RP-set information to other
routers.
The RP election process is as follows:
1 C-BSRs ood their candidacy throughout the domain in a BSM. Each message contains a BSR priority value, and the C-BSR with the
highest priority value becomes the BSR.
2 Each C-RP unicasts periodic Candidate-RP-Advertisements to the BSR. Each message contains an RP priority value and the group
ranges for which it is a C-RP.
3 The BSR collects the most ecient group-to-RP mappings and periodically updates it to all PIM routes in the network.
4 The BSR oods the RP-Set throughout the domain periodically in case new C-RPs are announced, or an RP failure occurs.
Constraints
1 When a multicast group range is removed from the ACL group list, the E-BSR sends the advertisements to the group with hold-time
as 0 only when the C-RP timer expires. Till the timer expires, the C-RP will act as a RP for that multicast group.
2 In E-BSR, if the C-RP advertisements are not in synchronization with the standby, rst few BCM C-RP advertisement might not have
the complete list of RP mappings. Due to this, there is a possibility of RP mapping timeout and momentary trac loss in the network.
3 If you congure a secondary VLT peer as an E-BSR and in case of ICL ap or failover, the VLT lag will be down resulting a BSM
timeout in the PIM domain and a new BSR will be elected. Hence, it is recommended to congure the primary VLT peer as E-BSR.
To enable BSR election for IPv4 or IPv6, perform the following steps:
1 Enter the following IPv4 or IPv6 command to make a PIM router a BSR candidate:
CONFIGURATION
ip pim bsr-candidate
ipv6 pim bsr-candidate
2 Enter the following IPv4 or IPv6 command to make a PIM router a RP candidate:
CONFIGURATION
ip pim rp-candidate
ipv6 pim rp-candidate
3 Display IPv4 or IPv6 Bootstrap Router information.
EXEC Privilege
show ip pim bsr-router
Example:
DellEMC# show ip pim bsr-router
PIMv2 Bootstrap information
This system is the Bootstrap Router (v2)
BSR address: 7.7.7.7 (?)
BSR Priority: 0, Hash mask length: 30
Next bootstrap message in 00:00:08
This system is a candidate BSR
Candidate BSR address: 7.7.7.7, priority: 0, hash mask length: 30
DellEMC#
show ipv6 pim bsr-router
Example:
DellEMC#show ipv6 pim bsr-router
PIMv2 Bootstrap information
PIM
Source-Specic Mode (PIM-SSM) 739