Dell S4048-ON, Configuration Manual

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Clearing the Source-Active Cache
To clear the source-active cache, use the following command.
• Clear the SA cache of all, local, or rejected entries, or entries for a specific group.
CONFIGURATION mode
clear ip msdp sa-cache [group-address | local | rejected-sa]
Enabling the Rejected Source-Active Cache
To cache rejected sources, use the following command.
Active sources can be rejected because the RPF check failed, the SA limit is reached, the peer RP is unreachable, or the SA message
has a format error.
• Cache rejected sources.
CONFIGURATION mode
ip msdp cache-rejected-sa
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.
Referring to the following illustrations:
• In Scenario 1, 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, 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.
Multicast Source Discovery Protocol (MSDP)
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