Methods for implementing a talkgroup call with competing sources in a multicast ip network

Abstract

Methods for implementing talkgroup calls in an IP multicast network among competing sources, including console dispatch takeover of an active call from a subscriber, subscriber unit attempted takeover of an active call from a console, and operation of communication devices in different receive modes. In the takeover or attempted takeover situation, the methods allow for a first group of participating devices (e.g., consoles) to hear both competing sources, and for a second group of participating devices (e.g., base site repeaters) to hear only the higher priority source. The methods allow for different dekeying sequences between the competing sources after the takeover or attempted takeover, as appropriate, such that participating devices will hear the remaining source. Where multiple payloads are addressed to the same multicast group address, an exclusive receive mode enables a group of communication devices (e.g., base site repeaters) having joined the address to exclusively receive a selected one of the payloads.