Reference Guide

602 | Multicast Source Discovery Protocol
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State: Established Up/Down Time: 00:15:20
Timers: KeepAlive 30 sec, Hold time 75 sec
SourceActive packet count (in/out): 8/0
SAs learned from this peer: 1
SA Filtering:
Input (S,G) filter: none
Output (S,G) filter: none
Multicast sources in remote domains are stored on the RP in the Source-active cache (SA cache). The
system does not create entries in the multicast routing table until there is a local receiver for the
corresponding multicast group.
Manage the Source-active Cache
Each SA-originating RP caches the sources inside its domain (domain-local), and the sources which it has
learned from its peers (domain-remote). By caching sources:
• domain-local receivers experience a lower join latency,
• RPs can transmit SA messages periodically to prevent SA storms, and
• only sources that are in the cache are advertised in the SA to prevent transmitting multiple copies of
the same source information.
View the Source-active Cache
R3_E600#show ip msdp sa-cache
MSDP Source-Active Cache - 1 entries
GroupAddr SourceAddr RPAddr LearnedFrom Expire UpTime
239.0.0.1 10.11.4.2 192.168.0.1 192.168.0.1 76 00:10:44
Limit the Source-active Cache
Set the upper limit of the number of active sources that FTOS caches. The default active source limit is
500K messages. When the total number of active sources reaches the specified limit, subsequent active
sources are dropped even if they pass the RPF and policy check.
If the total number of active sources is already larger than the limit when limiting is applied, the sources
that are already in FTOS are not discarded. To enforce the limit in such a situation, use the command
clear
ip msdp sa-cache
to clear all existing entries.
Task Command Syntax Command Mode
View the SA cache. show ip msdp sa-cache EXEC Privilege
Task Command Syntax Command Mode
Limit the number of sources that can be stored in the SA cache. show ip msdp sa-limit EXEC Privilege