Configuring a Single Static RP
If you are configuring PIM sparse mode, you must configure a PIM RP for a multicast group. An RP can
either be configured statically in each device, or learned through a dynamic mechanism. This task
explains how to statically configure an RP, as opposed to the router learning the RP through a dynamic
mechanism such as Auto-RP.
PIM designated routers (DRs) forward data from directly connected multicast sources to the RP for
distribution down the shared tree. Data is forwarded to the RP in one of two ways. It is encapsulated in
register packets and unicast directly to the RP, or, if the RP has itself joined the source tree, it is multicast
forwarded per the RPF forwarding algorithm. Last hop routers directly connected to receivers may, at
their discretion, join themselves to the source tree and prune themselves from the shared tree.
A single RP can be configured for multiple groups that are defined by an access list. If no RP is
configured for a group, the router treats the group as dense using the PIM dense mode techniques. (You
can prevent this occurrence by configuring the no ip pim dm-fallback command.)
If a conflict exists between the RP configured with the ip pim rp-address command and one learned by
Auto-RP, the Auto-RP information is used, unless the override keyword is configured.