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Configuring SA Message Transmission 593
Configuring MSDP Peer
Connection Control
The connection between MSDP peers can be flexibly controlled. You can disable the
MSDP peering relationships temporarily by shutting down the MSDP peers. As a
result, SA messages cannot be transmitted between such two peers. On the other
hand, when resetting an MSDP peering relationship between faulty MSDP peers or
bringing faulty MSDP peers back to work, you can adjust the retry interval of
establishing a peering relationship through the following configuration.
Configuring SA
Message Transmission
An SA message contains the IP address of the multicast source S, multicast group
address G, and RP address. In addition, it contains the first multicast data received by
the RP in the domain where the multicast source resides. For some burst multicast
data, if the multicast data interval exceeds the SA message hold time, the multicast
data must be encapsulated in the SA message; otherwise, the receiver will never
receive the multicast source information.
By default, when a new receiver joins in, a router does not send an SA request
message to its MSDP peer but has to wait for the next SA message. This defers the
reception of the multicast information by the receiver. In order for the new receiver to
know about the currently active multicast source as quickly as possible, the router
needs to send SA request messages to the MSDP peer.
Generally, a router accepts all SA messages sent by all MSDP peers and sends all SA
messages to all MSDP peers. By configuring the rules for filtering SA messages to
receive/send, you can effectively control the transmission of SA messages among
MSDP peers. For forwarded SA messages, you can also configure a Time-to-Live (TTL)
threshold to control the range where SA messages carrying encapsulated data are
transmitted.
To reduce the delay in obtaining the multicast source information, you can cache SA
messages on the router. The number of SA messages cached must not exceed the
system limit. The more messages cached, the more router memory occupied;
therefore, be flexible when dealing with the cache size.
Configuration
Prerequisites
Before you configure SA message transmission, perform the following tasks:
■ Configuring a unicast routing protocol.
■ Configuring basic IP multicast functions.
■ Configuring basic PIM-SM functions.
■ Configuring basic MSDP functions.
Table 648 Configure MSDP peer connection control
Operation Command Description
Enter system view system-view -
Enter MSDP view msdp -
Shut down an MSDP peer shutdown peer-address Optional
Configure retry interval of setting
up an MSDP peer connection
timer retry seconds Optional
The default value is 30
seconds.