3Com Switch 8800 Advanced Software V5 Configuration Guide

Configuring SA Messages Related Parameters 621
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■ With the function of sending SA request messages enabled, when receiving a
Join message from a new multicast receiver, the device sends an SA request
message to the remote MSDP peer specified by this command, and the remote
peer responds with cached SA information. Upon sending an SA request
message, the device receives the information about all the active multicast
sources.
■ If you do not specify an ACL when configuring an SA message filtering rule, all
the SA requests sent by the device’s MSDP peers will be ignored. If you specify
an ACL, SA request messages complying with the filtering rule will be
accepted, while all other SA request messages will be ignored.
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CAUTION: Before you can enable the device to send SA requests, be sure to
disable the SA message cache mechanism.
Configuring an SA
Message Filtering Rule
By configuring an SA message creation rule, you can enable the device to filter the
(S, G) entries to be advertised when creating an SA message, so that the
propagation of messages of multicast sources is controlled.
In addition to controlling SA message creation, you can also configure filtering
rules for forwarding and receiving SA messages, so as to control the propagation
of multicast source information in the SA messages.
■ By configuring a filtering rule for receiving or forwarding SA messages, you can
enable the device to filter the (S, G) forwarding entries to be advertised when
receiving or forwarding an SA message, so that the propagation of multicast
source information is controlled at SA message reception or forwarding.
■ An SA message with encapsulated multicast data can be forwarded to a
designated MSDP peer only if the TTL value in its IP header exceeds the
threshold. Therefore, you can control the forwarding of such an SA message by
configuring the TTL threshold of the encapsulated data packet.
Follow these steps to configure a filtering rule for receiving or forwarding SA
messages:
To do... Use the command... Remarks
Enter system view system-view -
Enter MSDP view msdp -
Enable sending SA request
messages
peer peer-address
request-sa-enable
Optional
Disabled by default
Configure a filtering rule for
SA request messages
peer peer-address
sa-request-policy [ acl
acl-number ]
Optional
SA request messages are not
filtered by default
To do... Use the command... Remarks
Enter system view system-view -
Enter MSDP view msdp -
Configuring an SA message
creation rule
import-source [ acl
acl-number ]
Required
No restrictions on (S, G)
entries by default