PIM version 2 implements a bootstrap router (BSR) mechanism as an alternative to the statically configured RP. In this topology, the RP is not configured. Instead, a number of multicast-enabled routers are configured as BSR and RP candidates.
BSR candidates announce themselves to other routers by using the PIM Multicast version 2 IP address (22.214.171.124). The candidacy message is forwarded through the network, and the BSR is elected from the candidates on the basis of its configured BSR priority. BSR becomes the source of the RP mapping information, calculates the RPs from the RP candidates information. BSR then disseminates the RP mapping information throughout the whole PIM enabled network.