Huawei Quidway S3900 Series Operation Manual page 437

Operation Manual – Multicast Protocol
Quidway S3900 Series Ethernet Switches-Release 1510
(SPT) based on the multicast source S. However, a rendezvous point tree (RPT) exists
between RP4 and receivers in the PIM-SM4 domain.
Note:
Through MSDP, a PIM-SM domain receiving information from the multicast source S
does not rely on RPs in other PIM-SM domains, that is, receivers can directly join the
SPT tree based on the multicast source without passing RPs in other PIM-SM domains.
II. MSDP application
You can also implement Anycast RP through MSDP. Anycast RP refers to such an
application that an MSDP peering relationship can be established between two RPs
with the same IP address in the same PIM-SM domain, to enable load balancing and
redundancy backup between the two RPs in the same domain. The candidate RP
(C-RP) function is enabled on an interface (typically the loopback interface) of each of
multiple routers in the same PIM-SM domain, and these interfaces have the same IP
address. An MSDP peering relationship is formed among these interfaces, as shown in
Figure 8-2.
S1
user
Figure 8-2 Typical networking of Anycast RP
Typically, a multicast source S registers to the nearest RP to create an SPT, and
receivers also send Join messages to the nearest RP to construct an RPT, so it is likely
that the RP to which the multicast source has registered is not the RP that receivers
Join. To ensure information consistency between RPs, the RPs, serving as MSDP
peers of one another, learn information of the peer multicast source by sending SA
messages to one another. As a result, each RP can know all the multicast sources in
the PIM-SM domain. In this way, the receivers connected to each RP can receive
multicast data sent by all the multicast sources in the entire PIM-SM domain.
As described above, RPs exchange information among one another through MSDP, a
multicast source registers with the nearest RP, and receivers join the nearest RPT, so
RP1
PIM-SM
user
SA message
MSDP peers
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RP2
SA
MSDP
8-3
Chapter 8 MSDP Configuration
S2
user
user
user