Operation Manual – MulticastH3C S5600 Series Ethernet Switches Chapter 5 MSDP Configuration5-165.4.6 Configuring a Rule for Filtering Received and Forwarded SA MessagesBesides the creation of source information, controlling multicast source informationallows you to control the forwarding and reception of source information. You cancontrol the reception of SA messages using the MSDP inbound filter (corresponding tothe import keyword); you can control the forwarding of SA messages by using eitherthe MSDP outbound filter (corresponding to the export argument) or the TTL threshold.MSDP inbound/outbound filter implements the following functions:z Filtering out all (S, G) entriesz Receiving/forwarding only the SA messages permitted by advanced ACL rules(You can configure ACL rules for filtering source IP addresses and group IPaddresses.)An SA message carrying encapsulated data can reach the specified MSDP peeroutside the domain only if the TTL in its IP header is greater than the threshold;therefore, you can control the forwarding range of SA messages that carryencapsulated data by configuring the TTL threshold.Follow these steps to configure a rule for filtering received and forwarded SAmessages:To do... Use the command... RemarksEnter system view system-view —Enter MSDP view msdp —Configure to filterimported and exportedSA messagespeer peer-addresssa-policy { import |export } [ aclacl-number ]OptionalBy default, no filtering isimposed on SA messages tobe received or forwarded,namely all SA messages fromMSDP peers are received orforwarded.Configure the minimumTTL required for amulticast packet to besent to the specifiedMSDP peerpeer peer-addressminimum-ttl ttl-valueOptionalBy default, the value of TTLthreshold is 0.
