IPv6 PIM Sparse Router Types

Routers that are configured with IPv6 PIM Sparse interfaces also can be configured to fill one or more of the following roles:

  • BSR - The Bootstrap Router (BSR) distributes RP information to the other IPv6 PIM Sparse routers within the domain. Each IPv6 PIM Sparse domain has one active BSR. For redundancy, you can configure ports on multiple routers as candidate BSRs. The IPv6 PIM Sparse protocol uses an election process to select one of the candidate BSRs as the BSR for the domain. The BSR with the highest BSR priority (a user-configurable parameter) is elected. If the priorities result in a tie, then the candidate BSR interface with the highest IP address is elected. In the example in Figure 1, IPv6 PIM Sparse router B is the BSR. Port 1/2/2 is configured as a candidate BSR.
  • RP - The Rendezvous Point (RP) is the meeting point for IPv6 PIM Sparse sources and receivers. A IPv6 PIM Sparse domain can have multiple RPs, but each PIM Sparse multicast group address can have only one active RP. IPv6 PIM Sparse routers learn the addresses of RPs and the groups for which they are responsible from messages that the BSR sends to each of the IPv6 PIM Sparse routers. In the example in Figure 1, IPv6 PIM Sparse router B is the RP. Port 1/2/2 is configured as a candidate Rendezvous Point (RP).

To enhance overall network performance, the device uses the RP to forward the packets from a group source to the group receivers. Later, the receiver calculates the shortest path between the receiver and the source (the Shortest Path Tree, or SPT) and uses the SPT for subsequent packets from the source to the receiver. The device calculates a separate SPT for each source-receiver pair.

Note: It is recommended that you configure the same ports as candidate BSRs and RPs.