Configuring Sa Message Contents; Configuring Sa Request Messages - HP 6125XLG Ip Multicast Configuration Manual

Configure basic MSDP functions.
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Configuring SA message contents

Some multicast sources send multicast data at an interval longer than the aging time of (S, G) entries. In
this case, the source-side DR must encapsulate multicast data packet-by-packet in 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 configure the source-side RP to encapsulate multicast data in SA
messages. 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.
The MSDP peers deliver SA messages to one another. After receiving an SA message, a router performs
an RPF check on the message. If the router finds that the remote RP address is the same as the local RP
address, it discards the SA message.
However, in the Anycast RP application, you must configure the same IP address for the RPs in the same
PIM-SM domain and configure these RPs as MSDP peers. To make sure SA messages can pass the RPF
check, you must assign SA messages a logical RP address that is different than the actual RP address. A
logical RP address is the address of a logical interface on the router where the RP resides.
To configure the SA message contents:
Step
1. Enter system view.
2. Enter MSDP view.
3. Enable multicast data
encapsulation in SA
messages.
4. Configure the interface
address as the RP address
in SA messages.

Configuring SA request messages

By default, after receiving a new join message, a router does not send an SA request message to any
MSDP peer. Instead, it waits for the next SA message from its MSDP peer. This will cause the receiver to
delay obtaining multicast source information.
To reduce the join latency, you can configure the router to send SA request messages to the designated
MSDP peers after receiving a join message of a new receiver.
IMPORTANT:
Before you enable the router to send SA requests, be sure to disable the SA message cache mechanism.
To configure SA request transmission and filtering:
Command
system-view
msdp [ vpn-instance vpn-instance-name ]
encap-data-enable
originating-rp interface-type
interface-number
149
Remarks
N/A
N/A
By default, an SA message
contains only (S, G) entries,
but not the multicast data.
By default, PIM RP address is
the RP address in SA
messages.