H3C Technologies H3C S7500E Series Switches - Manual (Page 214)

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z Configure any unicast routing protocol so that all devices in the domain are interoperable at the
network layer.
z Configuring basic functions of MSDP
Before configuring SA message delivery, prepare the following data:
z ACL rules for filtering SA request messages
z ACL rules as SA message creation rules
z ACL rules for filtering SA messages to be received and forwarded
z TTL threshold for multicast packet encapsulation in SA messages
z Maximum number of (S, G) entries learned from the specified MSDP peer that the router can
cache
Configuring SA Message Content
Some multicast sources send multicast data at an interval longer than the aging time of (S, G) entries.
In this case, the source-side DR has to encapsulate multicast data packet by packet in register
messages and send them to the source-side RP. The source-side RP transmits the (S, G) information
to the remote RP through SA messages. Then the remote RP joins the source-side DR and builds an
SPT. Since the (S, G) entries have timed out, remote receivers can never receive the multicast data
from the multicast source.
If the source-side RP is enabled to encapsulate register messages in SA messages, when there is a
multicast packet to deliver, the source-side RP encapsulates a register message containing the
multicast packet in an SA message and sends it out. After receiving the SA message, the remote RP
decapsulates the SA message and delivers the multicast data contained in the register message to the
receivers along the RPT.
The MSDP peers deliver SA messages to one another. Upon receiving an SA message, a router
performs RPF check on the message. If the router finds that the remote RP address is the same as
the local RP address, it will discard the SA message. In the Anycast RP application, however, you
need to configure RPs with the same IP address on two or more routers in the same PIM-SM domain,
and configure these routers as MSDP peers to one another. Therefore, a logic RP address (namely
the RP address on the logic interface) that is different from the actual RP address must be designated
for SA messages so that the messages can pass the RPF check.
Follow these steps to configure the SA message content:
To do... Use the command... Remarks
Enter system view system-view —
Enter public instance MSDP view or
VPN instance MSDP view
msdp [ vpn-instance
vpn-instance-name ]
—
Enable encapsulation of a register
message
encap-data-enable
Optional
Disabled by default
Configure the interface address as the
RP address in SA messages
originating-rp interface-type
interface-number
Optional
PIM RP address by default