Controlling the Sending of SA Request Messages

If the Source Active (SA) cache capacity is large on a remote MSDP peer, to shorten the time taken by a receiver to obtain multicast source information, enable the local Rendezvous Point (RP) to send SA Request messages, and configure a policy on the peer to filter SA Request messages to be received from the local RP.

Context

If the local RP has a small SA cache capacity and needs to receive multicast data, the local RP cannot immediately obtain useful (S, G) information. Instead, it has to wait for the SA message sent by the remote MSDP peer in the next sending period.

If the SA cache function is enabled and the SA cache capacity is large on the remote MSDP peer, enable the local RP to send SA Request messages to shorten the time taken by a receiver to obtain multicast source information.

When the local RP needs to receive (S, G) information, it actively sends an SA Request message to the specified remote MSDP peer rather than waits for the SA message sent in the next sending period.
Upon receipt of the SA Request message, the remote MSDP peer responds with an SA Response message carrying the required (S, G) information.

If the remote MSDP peer is configured to filter SA Request messages to be received, the remote peer responds to only the SA Request messages that matches the specified rule.

Procedure

Enable the local RP to send SA Request messages.
1. Run system-view
  The system view is displayed.
2. Run msdp [ vpn-instance vpn-instance-name ]
  The MSDP view is displayed.
3. Run peer peer-address request-sa-enable
  The local RP is enabled to send SA Request messages to a specified MSDP peer.
  
  peer-address: specifies the IP address of a remote MSDP peer. When the local RP receives a new Join message, it sends an SA Request message only to the peer specified by peer-address.
  
  Before running this command on the local RP, disable the SA cache function on the local RP and ensure that the SA cache function is enabled on the MSDP peer specified by peer-address.
4. Run commit
  The configuration is committed.
Configure a policy on the remote MSDP peer to filter SA Request messages to be received.
1. Run system-view
  The system view is displayed.
2. Configure a basic numbered ACL or a naming ACL as needed.
  - Configure a basic numbered ACL.
    1. Run acl [ number ] basic-acl-number [ match-order { auto | config } ]
      A basic numbered ACL is created, and the basic numbered ACL view is displayed.
    2. Run rule [ rule-id ] [ name rule-name ] { deny | permit } source { source-ip-address { source-wildcard | 0 } | any }
      Rules are configured for the basic numbered ACL.
    3. Run quit
      Return to the system view.
  - Configure a naming ACL.
    1. Run acl name acl-name basic [ match-order { auto | config } ]
      A naming ACL is created, and the naming ACL view is displayed.
    2. Run rule [ rule-id ] [ name rule-name ] { deny | permit } ip [ destination { destination-ip-address { destination-wildcard | 0 } | any } | source { source-ip-address { source-wildcard | 0 } | any } ] ^*
      Rules are configured for the naming ACL
    3. Run quit
      Return to the system view.
  If a basic numbered ACL is used, run the rule command and set the source parameter to the multicast group address.
  
  If a naming ACL is used, run the rule command and set the destination parameter to a multicast group address.
3. Run msdp [ vpn-instance vpn-instance-name ]
  The MSDP view is displayed.
4. Run peer peer-address sa-request-policy [ acl { basic-acl-number | acl-name } ]
  A policy is configured on the MSDP peer to filter SA Request messages to be received.
  - peer-address: specifies the address of the MSDP peer that sends SA Request messages.
  - acl basic-acl-number and acl-name: defines a filtering policy.
  - If an SA Request message matches an ACL rule and the action is permit, the interface permits this message.
  - If an SA Request message matches an ACL rule and the action is deny, the interface denies this message.
  - If an SA Request message does not match any ACL rule, the device denies this message.
  - If a specified ACL does not exist or does not contain rules, the device ignores all SA Request messages from this peer.
5. Run commit
  The configuration is committed.