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register messages and send them to the source-side RP. The source-side RP transmits the (S, G)
information to the remote RP through SA messages. Then, the remote RP sends join messages to
the source-side DR and builds an SPT. Because the (S, G) entries have timed out, remote receivers
can never receive the multicast data from the multicast source.
To avoid this problem, you can enable the source-side RP to encapsulate multicast data in SA
messages. As a result, the source-side RP can forward the multicast data in SA messages to its
remote MSDP peers. After receiving the SA messages, the remote RP decapsulates the SA
messages and forwards the multicast data to the receivers in the local domain along the RPT.
To enable multicast data encapsulation in SA messages:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter MSDP view.
msdp
[
vpn-instance
vpn-instance-name
]
N/A
3.
Enable
multicast
data
encapsulation
in
SA
messages.
encap-data-enable
By default, an SA message
contains only (S, G) entries,
but not the multicast data.
Configuring the originating RP of SA messages
This feature enables an interface to originate SA messages and to use its IP address as the RP
address in SA messages. It is typically used in the Anycast-RP application.
By default, the RP address in SA messages originated by a member Anycast-RP is the Anycast-RP
address. The SA messages will fail the RPF check on the other members because the RP address in
SA messages is the same as the local RP address. In this case, source information cannot be
exchanged within the Anycast-RP. To solve the problem, you must specify an interface other than the
interface where the member Anycast-RP resides as the originating RP of SA messages.
To configure the originating RP of SA messages:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter MSDP view.
msdp
[
vpn-instance
vpn-instance-name
]
N/A
3.
Configure an interface as the
originating
RP
of
SA
messages.
originating-rp
interface-type
interface-number
By default, SA messages are
originated by the actual RPs.
Configuring SA request messages
By default, after receiving a new join message, a router waits for an SA message to obtain the
multicast source information and to join the SPT. You can enable the router to request source
information by sending SA request messages to an MSDP peer. This reduces the join latency.
An SA request policy enables the device to filter SA request messages from an MSDP peer by using
an ACL that specifies the multicast groups.
IMPORTANT:
Before you enable the router to send SA requests, make sure you disable the SA message cache
mechanism.
