Administrator Guide

Electing an RP using the BSR Mechanism
Every PIM router within a domain must map a particular multicast group address to the same RP. The group-to-RP mapping may be
statically or dynamically congured. RFC 5059 species a dynamic, self-conguring method called the Bootstrap Router (BSR) mechanism,
by which an RP is elected from a pool of RP candidates (C-RPs).
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 determines the most ecient and stable group-to-RP mappings, which is called the RP-Set.
4 The BSR oods the RP-Set throughout the domain periodically in case new C-RPs are announced, or an RP failure occurs.
To enable RP election, perform the following steps:
1 Enter the following command to make a PIM router a BSR candidate:
CONFIGURATION
ip pim bsr-candidate
2 Enter the following command to make a PIM router a RP candidate:
CONFIGURATION
ip pim rp-candidate
3 Display Bootstrap Router information.
EXEC Privilege
show ip pim bsr-router
Enabling RP to Server Specic Multicast Groups
When you congure an RP candidate, its advertisement is sent to the entire multicast address range and the group-to-RP mapping is
advertised for the entire range of multicast address. Starting with Dell Networking OS 9.11.0.0, you can congure an RP candidate for a
specied range of multicast group address.
The Congured multicast group ranges are used by the BSR protocol to advertise the candidate RPs in the bootstrap messages.
You can congure the multicast group ranges as a standard ACL list of multicast prexes. You can then associate the congured group list
with the RP candidate.
NOTE
: • If there is no multicast group list congured for the RP-candidate, the RP candidate will be advertised for all the
multicast groups.
To enable an RP to serve specic group of multicast addresses, perform the following step:
Enter the following command to associate a multicast group to an RP candidate:
CONFIGURATION
PIM
Source-Specic Mode (PIM-SSM) 713