Patent ID: 7075929

Claim:
In a wireless communication system comprising a plurality of communication devices and a plurality of sites organized into one or more zones, a method comprising: receiving a request for a call from a sourcing device of the plurality of devices, wherein the sourcing device comprises a sourcing site of the plurality of sites and is in a first zone of the communication system; determining locations of one or more participating devices for the call at one or more destination sites; based on the locations of the participating devices, assigning a first multicast scope value to the call; sending the first multicast scope value to the participating devices at the one or more destination sites; sending, from the sourcing site to a first router element, one or more IP packets including the multicast scope value and addressed to a multicast group address; and routing the IP packets by the first router element with a decremented multicast scope value, according to a dense mode routing protocol, across one or more router interfaces of the first router element to the one or more destination sites.