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Operation Manual – Multicast Protocol
Quidway S5600 Series Ethernet Switches-Release 1510
Chapter 7 PIM Configuration
Huawei Technologies Proprietary
7-8
C-BSR
C-RP
C-RP
BSR
C-RP
BSR message
C-RP advertisement
Figure 7-4
Diagram for the communication between RPs and BSRs
Only one BSR can be elected in a network or management domain, while multiple
candidate BSRs (C-BSR) can be configured. In this case, once the BSR fails, other
C-BSRs can elect a new BSR through auto-election. Thus, the service is prevented
from being interrupted.
In the same way, multiple C-RPs can be configured in a PIM-SM domain, the RP
corresponding to each multicast group is worked out through the BSR mechanism.
IV. RPT building
Assume the receiver hosts are User B, User D, and User E. When a receiver host joins
in a multicast group G, it will inform the leaf router directly connected to the host through
IGMP packets. Thus the leaf router masters the receiver information of the multicast
group G, and then the leaf router will send Join messages to the upper-layer nodes in
the direction of RP, as shown in Figure 7-5:
RP
Server
Multicast
User A
User B
User C
User D
User E
Join
Join
Join
Source
Receiver
Receiver
Receiver
packets
Join
RPT
Figure 7-5
Diagram for RPT building in PIM-SM