Information
PIM Bootstrap messages (BSMs) play a crucial role in electing a Rendezvous Point (RP) for multicast routing within a domain. However, exchanging these messages across different multicast domains is undesirable, as it can result in the unintended election of an RP in a domain where it does not belong, disrupting multicast operations. To address this, the bsr-boundary configuration can be applied to boundary interfaces, ensuring that PIM BSMs originating from external domains are dropped and that internally generated BSMs are confined to their domain.
The rationale for restricting the propagation of PIM Bootstrap messages across multicast boundaries is to preserve the integrity and isolation of domain-specific RP elections. Allowing such messages to traverse domains can lead to conflicts or misconfigurations, where RPs are incorrectly elected in domains they are not supposed to serve. By using the bsr-boundary feature, network administrators can enforce strict boundaries, ensuring that multicast routing remains consistent and domain-specific, preventing cross-domain interference.
NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.
Solution
Configuration to enable Multicast BSR Boundary -
switch(config)# interface <ID>
switch(config-int)# ip pim-sparse bsr-boundary
Impact:
Implementing the bsr-boundary configuration has a significant impact on maintaining the stability and efficiency of multicast routing. It prevents RP election conflicts across domains, ensuring that each multicast domain operates independently and without disruption.