Reference Guide

Multicast Source Discovery Protocol (MSDP) | 525
Enable the Rejected Source-active Cache
Active sources can be rejected because
• the RPF check failed,
• the SA limit is reached,
• the peer RP is unreachable,
• or because of an SA message format error.
Accept Source-active Messages that fail the RFP Check
A default peer is a peer from which active sources are accepted even though they fail the RFP check.
• In Scenario 1 of Figure 24-10, all MSPD peers are up.
• In Scenario 2, the peership between RP1 and RP2 is down, but the link (and routing protocols)
between them is still up. In this case, RP1 learns all active sources from RP3, the but the sources from
RP2 and RP4 are rejected because the reverse path to these routers is through Interface A.
• In Scenario 3, RP3 is configured as a default MSDP peer for RP1 and so the RPF check is disregarded
for RP3.
• In Scenario 4, RP1 has a default peer plus an access list. The list permits RP4 so the RPF check is
disregarded for active sources from it, but RP5 (and all others because of the implicit deny all) are
subject to the RPF check and fail, so those active sources are rejected.
Task Command Syntax Command Mode
Cache rejected sources. ip msdp cache-rejected-sa CONFIGURATION