Operation Manual – Multicast Protocol
H3C S3610&S5510 Series Ethernet Switches
Chapter 7 MSDP Configuration
7-6
SA message
MSDP peers
AS 1
AS 2
AS 3
AS 4
AS 5
RP 1
RP 2
RP 3
RP 4
RP 5
RP 6
RP 7
RP 8
RP 9
Mesh group
Source
(1)
(2)
(3)
(3)
(4)
(7)
(6)
(5)
(4)
Static RPF peers
Figure 7-3
Diagram for RPF check for SA messages
As illustrated in
, these MSDP peers dispose of SA messages according to
the following RPF check rules:
1)
When RP 2 receives an SA message from RP 1
Because the source-side RP address carried in the SA message is the same as the
MSDP peer address, which means that the MSDP peer where the SA is from is the RP
that has created the SA message, RP 2 accepts the SA message and forwards it to its
other MSDP peer (RP 3).
2)
When RP 3 receives the SA message from RP 2
Because the SA message is from an MSDP peer (RP 2) in the same AS, and the MSDP
peer is the next hop on the optimal path to the source-side RP, RP 3 accepts the
message and forwards it to other peers (RP 4 and RP 5).
3)
When RP 4 and RP 5 receive the SA message from RP 3
Because the SA message is from an MSDP peer (RP 3) in the same mesh group, RP 4
and RP 5 both accept the SA message, but they do not forward the message to other
members in the mesh group; instead, they forward it to other MSDP peers (RP 6 in this
example) out of the mesh group.
4)
When RP 6 receives the SA messages from RP 4 and RP 5 (suppose RP 5 has a
higher IP address)
Although RP 4 and RP 5 are in the same AS (AS 3) and both are MSDP peers of RP 6,
because RP 5 has a higher IP address, RP 6 accepts only the SA message from RP 5.
5)
When RP 7 receives the SA message from RP 6
Because the SA message is from a static RPF peer (RP 6), RP 7 accepts the SA
message and forwards it to other peer (RP 8).
6)
When RP 8 receives the SA message from RP 7
