3Com Switch 4800G 24-Port Configuration Manual page 698

698 C 48: MSDP C
HAPTER
No SA Entries in the
Router's SA Cache
Inter-RP Communication
Faults in Anycast RP
Application
ONFIGURATION
Symptom
MSDP fails to send (S, G) entries through SA messages.
Analysis
The import-source command is used to control sending (S, G) entries through
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SA messages to MSDP peers. If this command is executed without the
acl-number argument, all the (S, G) entries will be filtered off, namely no (S, G)
entries of the local domain will be advertised.
If the import-source command is not executed, the system will advertise all
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the (S, G) entries of the local domain. If MSDP fails to send (S, G) entries
through SA messages, check whether the import-source command has been
correctly configured.
Solution
1 Check that a route is available between the routers. Carry out the display ip
routing-table command to check whether the unicast route between the routers
is correct.
2 Check that a unicast route is available between the two routers that will become
MSDP peers to each other.
3 Check configuration of the import-source command and its acl-number
argument and make sure that ACL rule can filter appropriate (S, G) entries.
Symptom
RPs fail to exchange their locally registered (S, G) entries with one another in the
Anycast RP application.
Analysis
In the Anycast RP application, RPs in the same PIM-SM domain are configured
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to be MSDP peers to achieve load balancing among the RPs.
An MSDP peer address must be different from the anycast RP address, and the
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C-BSR and C-RP must be configured on different devices or interfaces.
If the originating-rp command is executed, MSDP will replace the RP address
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in the SA messages with the address of the interface specified in the command.
When an MSDP peer receives an SA message, it performs RPF check on the
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message. If the MSDP peer finds that the remote RP address is the same as the
local RP address, it will discard the SA message.
Solution
1 Check that a route is available between the routers. Carry out the display ip
routing-table command to check whether the unicast route between the routers
is correct.
2 Check that a unicast route is available between the two routers that will become
MSDP peer to each other.
3 Check the configuration of the originating-rp command. In the Anycast RP
application environment, be sure to use the originating-rp command to
configure the RP address in the SA messages, which must be the local interface
address.