H3C Technologies H3C S3600 Series Switches - Manual (Page 443)

5-12
Configuring SA Message Cache
With the SA message caching mechanism enabled on the router, the group that a new member
subsequently joins can obtain all active sources directly from the SA cache and join the corresponding
SPT source tree, instead of waiting for the next SA message.
You can configure the number of SA entries cached in each MSDP peer on the router by executing the
following command, but the number must be within the system limit. To protect a router against Denial
of Service (DoS) attacks, you can manually configure the maximum number of SA messages cached on
the router. Generally, the configured number of SA messages cached should be less than the system
limit.
Follow these steps to configure SA message cache:
To do... Use the command... Remarks
Enter system view system-view —
Enter MSDP view msdp —
Enable SA message caching
mechanism
cache-sa-enable
Optional
Enabled by default
Configure the maximum
number of SA messages that
can be cached
peer peer-address
sa-cache-maximum sa-limit
Optional
The default is 2,048.
Configuring the Transmission and Filtering of SA Request Messages
After you enable the sending of SA request messages, when a router receives a Join message, it sends
an SA request message to the specified remote MSDP peer, which responds with an SA message that
it has cached. After sending an SA request message, the router will get immediately a response from all
active multicast sources. The SA message that the remote MSDP peer sends in response is cached in
advance; therefore, you must enable the SA message caching mechanism in advance. Typically, only
the routers caching SA messages can respond to SA request messages.
After you have configured a rule for filtering received SA messages, if no ACL is specified, all SA
request messages sent by the corresponding MSDP peer will be ignored; if an ACL is specified, the SA
request messages that satisfy the ACL rule are received while others are ignored.
Follow these steps to configure the transmission and filtering of SA request messages:
To do... Use the command... Remarks
Enter system view system-view —
Enter MSDP view msdp —
Enable SA message caching
mechanism
cache-sa-enable
Optional
By default, the router caches the
SA state upon receipt of an SA
message.
Enable MSDP peers to send
SA request messages peer peer-address
request-sa-enable
Optional
By default, upon receipt of a Join
message, the router sends no SA
request message to its MSDP peer
but waits for the next SA message.