cache-sa-enable

Function

The cache-sa-enable command enables the source active (SA) cache function on a router, allowing the router to cache (S, G) information carried in received SA messages.

The undo cache-sa-enable command disables the SA cache function.

By default, the SA cache function is enabled on a Router.

Format

cache-sa-enable

undo cache-sa-enable

Parameters

None

Views

VPN instance MSDP view, MSDP view of a public network instance

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
msdp	write

Usage Guidelines

Usage Scenario

To enable a Router to save (S, G) information carried in received SA messages locally, run the cache-sa-enable command to enable the SA cache function, so that the Router can obtain (S, G) information from the SA cache after receiving a multicast data service request.

If the SA cache function is disabled using the undo cache-sa-enable command, the Router must wait for an SA message sent by the Multicast Source Discovery Protocol (MSDP) peer in the next sending period after the router receives a multicast data service request. This may result in a delay in multicast data receiving.

Prerequisites

The multicast routing function has been enabled using the multicast routing-enable command in the public network instance view or VPN instance view.

Configuration Impact

When a rendezvous point (RP) receives a new (*, G) Join message,

If the SA cache function is enabled, the RP searches the SA cache for matching (S, G) information.
If the SA cache contains the (S, G) information, the RP directly joins the shortest path tree (SPT) with the multicast source at the root.
If the SA cache does not contain the (S, G) information, the RP does not process the Join message.
If the SA cache function is disabled, the RP waits for the SA message sent by the MSDP peer in the next sending period.

Example

# In the public network instance, disable the SA cache function.

<HUAWEI> system-view
[~HUAWEI] multicast routing-enable
[*HUAWEI] msdp
[*HUAWEI-msdp] undo cache-sa-enable