Configuring Sa Message Contents; Configuring Sa Request Messages - HP MSR2003 Configuration Manual

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. 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 RPs decapsulate the SA messages and forward
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 ensure that SA messages can pass the RPF
check, you must designate 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 SA message contents:
Step
1. Enter system view.
2. Enter MSDP view.
3. Enable
encapsulation
messages.
4. Configure
address as the RP address
in SA messages.

Configuring SA request messages

By default, after receiving a new join message, a router does not automatically 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 it receives a join message from 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:
Step
1. Enter system view.
Command
system-view
msdp [ vpn-instance vpn-instance-name ]
multicast data
in SA
encap-data-enable
an interface
originating-rp interface-type
interface-number
Command
system-view
148
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.
Remarks
N/A