Msdp Working Mechanism - Huawei Quidway S3900 Series Operation Manual

Operation Manual – Multicast Protocol
Quidway S3900 Series Ethernet Switches-Release 1510
RP load balancing can be achieved. When an RP fails, the multicast source and
receivers previously registered to/joined it will register to or join another nearest RP
automatically, thus implementing RP redundancy backup.

8.1.1 MSDP Working Mechanism

I. Identifying a multicast source and receiving multicast data
A network contains four PIM-SM domains, PIM-SM1, PIM-SM2, PIM-SM3, and
PIM-SM4. An MSDP peering relationship is established between RPs in different
domains. Multicast group members exist in the PIM-SM1 and PIM-SM4 domains. See
Figure 8-3.
Source
Figure 8-3 Identifying the multicast source and receiving multicast data
The complete interoperation process between a multicast source S in the PIM-SM1
domain and receivers in the PIM-SM1 and PIM-SM4 domains is as follows:
1) The multicast source S in the PIM-SM1 domain begins to send data packets.
2) The designated router (DR) connected to the multicast source S encapsulates the
received data in a Register message, and then forwards the message to RP1 in
the PIM-SM1 domain.
3) RP1 in the PIM-SM1 domain decapsulates the Register message, and then
forwards the message to all the members in the domain along the RPT. The
members in the domain can select whether to switch to the SPT.
4) At the same time, RP1 in the PIM-SM1 domain creates an SA message and sends
the message to the corresponding MSDP peers (RPs in the PIM-SM2 and
PIM-SM3 domains). Finally, the SA message is forwarded to the RP in the
PIM-SM4 domain. The SA message contains the IP address of the multicast
source, the multicast group address, the address of the RP that has generate the
SA message, and the first multicast data received by the RP in the PIM-SM1
domain.
(4)
RP1
(2)
(1)
(3)
DR
PIM-SM 1
user
Flow
MSDP peers
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RP2
PIM-SM 2
(4)
(5)
(4)
(4)
(5)
(4)
RP3
PIM-SM 3
8-4
Chapter 8 MSDP Configuration
user
(5)
RP4
PIM-SM 4