H3C S3610-28P Operation Manual page 828

Operation Manual – Multicast Protocol
H3C S3610&S5510 Series Ethernet Switches
1) The multicast source registers with the nearest RP. In this example, Source
registers with RP 1, with its multicast data encapsulated in the register message.
When the register message arrives to RP 1, RP 1 decapsulates the message.
2) Receivers send join messages to the nearest RP to join in the RPT rooted as this
RP. In this example, Receiver joins the RPT rooted at RP 2.
3) RPs share the registered multicast information by means of SA messages. In this
example, RP 1 creates an SA message and sends it to RP 2, with the multicast
data from Source encapsulated in the SA message. When the SA message
reaches RP 2, RP 2 decapsulates the message.
4) Receivers receive the multicast data along the RPT and directly join the SPT
rooted at the multicast source. In this example, RP 2 forwards the multicast data
down the RPT. When Receiver receives the multicast data from Source, it directly
joins the SPT rooted at Source.
The significance of Anycast RP is as follows:
Optimal RP path: A multicast source registers with the nearest RP so that an SPT
with the optimal path is built; a receiver joins the nearest RP so that an RPT with
the optimal path is built.
Load balancing between RPs: Each RP just needs to maintain part of the
source/group information within the PIM-SM domain and forward part of the
multicast data, thus achieving load balancing between different RPs.
Redundancy backup between RPs: When an RP fails, the multicast source
previously registered on it or the receivers previous joined it will register with or
join another nearest RP, thus achieving redundancy backup between RPs.
Caution:
Be sure to configure a 32-bit subnet mask (255.255.255.255) for the Anycast RP
address, namely configure the Anycast RP address into a host address.
An MSDP peer address must be different from the Anycast RP address.
7.1.3 Protocols and Standards
MSDP is documented in the following specifications:
RFC 3618: Multicast Source Discovery Protocol (MSDP)
RFC 3446: Anycast Rendezvous Point (RP) mechanism using Protocol
Independent Multicast (PIM) and Multicast Source Discovery Protocol (MSDP)
7-8
Chapter 7 MSDP Configuration