Users Guide

The RP election process is:
1 The C-BSRs announce their candidacy throughout the domain in BSMs. Each BSM contains a BSR priority. The C-BSR with the
highest priority becomes the BSR.
2 Each C-RP unicasts periodic candidate RP advertisements to the BSR. Each message contains an RP priority value and the multicast
group ranges for which the router is a C-RP.
3 The BSR determines the most ecient and stable group-to-RP mapping, which is called the RP-set formation.
4 The BSR sends the group-to-RP mapping sets to all the multicast routers. To select an RP from a set of RPs, multicast routers use
the algorithm that is specied in RFC 4601.
5 The BSR sends the group range-to-RP mappings to all the routers in the domain.
Conguration notes
• A PIM router supports only one candidate BSR per VRF instance.
• A PIM router supports only one candidate RP per VRF instance.
• You can congure a PIM BSR candidate and an RP candidate with Layer 3 (L3) VLAN, Loopback, physical, or port channel interface.
The system derives the IP address from this interface to determine the BSR or RP address.
• PIM BSR and RP candidate congurations are not supported on VXLAN bridge interfaces.
• Before you congure a candidate BSR:
– Enable multicast routing globally and establish PIM neighborship between routers. Ensure that the unicast routing table is populated.
– Congure an IP address on the candidate BSR interface.
• Before you congure a candidate RP:
– Enable multicast routing globally and establish PIM neighborship between routers. Ensure that the unicast routing table is populated.
– Ensure that the candidate RP can reach all the nodes in your network.
– (Optional) Congure an ACL with source as any and destination as a valid multicast group address. If you do not congure an ACL,
the router advertises itself as the RP for the entire multicast range, which is 224.0.0.0/4.
NOTE
:
◦ When you associate an ACL without any rules to an RP candidate, the system behaves dierently depending on the
order of the conguration:
• If you create the ACL without any rules rst and then associate it with the RP candidate, the router denies all
multicast groups.
• If you associate an ACL to an RP candidate that is not yet created in the system, and then congure the ACL
without any rules, the router advertises itself as the RP for the entire multicast range, 224.0.0.0/4.
◦ Do not use deny rules in the ACL that is used for RP candidate because it does not have any signicance.
To
congure dynamic RP using the BSR mechanism:
1 Congure a candidate BSR using the ip pim bsr-candidate command.
OS10# configure terminal
OS10(config)# interface ethernet 1/1/9
OS10(conf-if-eth1/1/9)# ip address 10.1.1.8/24
OS10(conf-if-eth1/1/9)# no shutdown
OS10(conf-if-eth1/1/9)# exit
OS10(config)# ip pim bsr-candidate ethernet 1/1/9 hash-mask-len 31 priority 255
To view the PIM candidate and elected BSR:
OS10# show ip pim bsr-router
This system is the Bootstrap Router (v2)
BSR address: 10.1.1.8
BSR Priority: 255, Hash mask length: 31
Next bootstrap message in 00:00:57
Multicast
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