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.
An SA request policy enables the switch to filter SA request messages by using an ACL that specifies the multicast groups. This reduces the join latency.
![[IMPORTANT: ]](images/important.png) | IMPORTANT: Before you enable the router to send SA requests, make sure you disable the SA message cache mechanism. | |
To configure SA request transmission and filtering:
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 the device to send SA request messages. | peer peer-address request-sa-enable | By default, after receiving a new join message, a device does not send an SA request message to any MSDP peer. Instead, it waits for the next SA message from its MSDP peer. |
4. Configure an SA request policy. | peer peer-address sa-request-policy [ acl acl-number ] | By default, no SA request policy exists. |