Specifications

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Cisco MWR 2941 Mobile Wireless Edge Router Software Configuration Guide, Release 12.2(33)MRB
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Appendix B Cisco MWR 2941 Router Command Reference
ip pim send-rp-discovery
Usage Guidelines Use the ip pim send-rp-discovery command to configure the router to be an RP mapping agent. An RP
mapping agent receives Auto-RP announcement messages, which it stores in its local group-to-RP
mapping cache. The RP mapping agent uses the information contained in the Auto-RP announcement
messages to elect the RP. The RP mapping agent elects the candidate RP with the highest IP address as
the RP for a group range.
The required scope keyword and ttl-value argument are used to specify the TTL value in the IP header
of Auto-RP discovery messages.
Note For the scope keyword and ttl-value argument, specify a TTL large enough to cover your Protocol
Independent Multicast (PIM) domain.
When Auto-RP is used, the following events occur:
1. The RP mapping agent listens for Auto-RP announcement messages sent by candidate RPs to the
well-known group address CISCO-RP-ANNOUNCE (224.0.1.39).
2. The RP mapping agents stores the information learned from Auto-RP announcement messages in its
local group-to-RP mapping cache.
3. The RP mapping agents elects the candidate RP with the highest IP address as the RP and announces
the RP in the Auto-RP discovery messages that it sends out.
4. The Auto-RP discovery messages that the RP mapping agent sends to the well-known group
CISCO-RP-DISCOVERY (224.0.1.40), which Cisco routers join by default, contains the elected RP
learned from the RP mapping agent’s group-to-RP mapping cache.
5. PIM designated routers listen for the Auto-RP discovery messages sent to 224.0.1.40 to learn the
RP and store the information about the RP in their local group-to-RP mapping caches.
Use the show ip pim rp command with the mapping keyword to display all the group-to-RP mappings
that the router has learned from Auto-RP.
Examples The following example shows how to configure a router to be an RP mapping agent. In this example, the
RP mapping agent is configured to use loopback 0 as the source address for Auto-RP messages. The
Auto-RP discovery messages sent by the RP mapping agent are configured to be sent out with a TTL of
20 hops.
ip pim send-rp-discovery loopback 0 scope 20
Related Commands Command Description
show ip pim rp Displays active RPs that are cached with associated multicast routing
entries.