The rendezvous point address is used by first-hop routers to send PIM register messages on behalf of a host
sending a packet to the group. The rendezvous point address is also used by last-hop routers to send PIM join
and prune messages to the rendezvous point to inform it about group membership. You must configure the
rendezvous point address on all routers (including the rendezvous point router).
A PIM router can be a rendezvous point for more than one group. Only one rendezvous point address can be
used at a time within a PIM domain. The conditions specified by the access list determine for which groups
the router is a rendezvous point.
You can either manually configure a PIM router to function as a rendezvous point or allow the rendezvous
point to learn group-to-RP mappings automatically by configuring Auto-RP or BSR. (For more information,
see the
Auto-RP, on page 17
section that follows and
PIM Bootstrap Router, on page 18
.)
Auto-RP
Automatic route processing (Auto-RP) is a feature that automates the distribution of group-to-RP mappings
in a PIM network. This feature has these benefits:
•
It is easy to use multiple RPs within a network to serve different group ranges.
•
It allows load splitting among different RPs.
•
It facilitates the arrangement of RPs according to the location of group participants.
•
It avoids inconsistent, manual RP configurations that might cause connectivity problems.
Multiple RPs can be used to serve different group ranges or to serve as hot backups for each other. To ensure
that Auto-RP functions, configure routers as candidate RPs so that they can announce their interest in operating
as an RP for certain group ranges. Additionally, a router must be designated as an RP-mapping agent that
receives the RP-announcement messages from the candidate RPs, and arbitrates conflicts. The RP-mapping
agent sends the consistent group-to-RP mappings to all remaining routers. Thus, all routers automatically
determine which RP to use for the groups they support.
By default, if a given group address is covered by group-to-RP mappings from both static RP configuration,
and is discovered using Auto-RP or PIM BSR, the Auto-RP or PIM BSR range is preferred. To override
the default, and use only the RP mapping, use the
rp-address override
keyword.
Tip
If you configure PIM in sparse mode and do not configure Auto-RP, you must statically configure an RP
as described in the
Configuring a Static RP and Allowing Backward Compatibility, on page 90
. When
router interfaces are configured in sparse mode, Auto-RP can still be used if all routers are configured
with a static RP address for the Auto-RP groups.
Note
Auto-RP is not supported on VRF interfaces. Auto-RP Lite allows you to configure auto-RP on the CE
router. It allows the PE router that has the VRF interface to relay auto-RP discovery, and announce
messages across the core and eventually to the remote CE. Auto-RP is supported in only the IPv4 address
family.
Note
Cisco IOS XR Multicast Configuration Guide for the Cisco CRS Router, Release 5.2.x
17
Implementing Multicast Routing on Cisco IOS XR Software
Auto-RP