Brocade BigIron RX Series Configuration Guide - Manual (Page 757)

BigIron RX Series Configuration Guide 679
53-1002484-04
PIM Sparse
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FIGURE 102 Example PIM Sparse domain
PIM Sparse router types
Routers that are configured with PIM Sparse interfaces also can be configured to fill one or more of
the following roles:
• PMBR – A PIM router that has some interfaces within the PIM domain and other interface
outside the PIM domain. PBMRs connect the PIM domain to the Internet.
NOTE
You cannot configure a Brocade routing interface as a PMBR interface for PIM Sparse in the
current software release.
• BSR – The Bootstrap Router (BSR) distributes RP information to the other PIM Sparse routers
within the domain. Each PIM Sparse domain has one active BSR. For redundancy, you can
configure ports on multiple routers as candidate BSRs. The 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 102 , PIM Sparse router B is the BSR. Port 2/2 is configured as a candidate BSR.
• RP – The RP is the rendezvous point for PIM Sparse sources and receivers. A PIM Sparse
domain can have multiple RPs, but each PIM Sparse multicast group address can have only
one active RP. 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 PIM Sparse routers. In the
example in
Figure 102 , PIM Sparse router B is the RP. Port 2/2 is configured as a candidate
Rendezvous Point (RP).
To enhance overall network performance, BigIron RX use the RP to forward only the first packet
PIM Sparse router B
Port2/1
207.95.8.10
Port2/2
207.95.7.1
Rendezvous Point (RP) path
Port3/8
207.95.8.1 Port3/8
207.95.7.2
VE 1
207.95.6.1 VE 1
207.95.6.2
Shortest Path Tree (SPT) path PIM Sparse router A PIM Sparse router C
209.157.24.162
Source for Group
239.255.162.1 Receiver for Group
239.255.162.1
This interface is also the
Bootstrap Router (BR) for
this PIM Sparse domain, and
the Rendezvous Point (RP) for the
PIM Sparse groups in this domain.