Systems and methods for implementing calls using pre-established multicast groups in a multicast IP network

Abstract

Systems and methods for implementing dispatch and/or point-to-point calls using pre-established multicast groups are disclosed. The methods include setting up and semi-permanently maintaining pre-established multicast group(s) in advance of prospective call(s), and utilizing the semi-permanent multicast groups when certain call requests are received to reduce call set up time and system loading. A zone controller identifies groups of endpoints that are expected to collectively participate in prospective call(s). The zone controller causes pre-established multicast groups to be established between the endpoints by distributing respective multicast group addresses to the endpoints in advance of prospective call(s). The endpoints, which may include adjacent sites, issue Join commands to associated network devices causing the network devices to establish a multicast routing tree for the multicast group. Later, upon a call request being received for a particular call, the zone controller identifies participating endpoints for the call. If the participating endpoints are members of a pre-established multicast group, the zone controller may cause payload for the call to be addressed to the multicast group address of the pre-established multicast group so that it may be distributed via the already-established multicast routing tree. If the participating endpoints are not members of a pre-established multicast group, the zone controller may establish a multicast group for the duration of the call.

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