Patent ID: 7620413

Claim:
A method of implementing push-to-talk (PTT) communication between network phone clients utilizing Session Initiation Protocol (SIP) Voice over Internet Protocol (VoIP) and multicast RTP mechanism, the method comprising: pushing a “Talk” button on a talking client to generate a PTT invitation message (SIP INVITE or MESSAGE); transmitting the PTT invitation message from the talking client to a SIP server; transmitting the PTT invitation message from the SIP server to a PTT server; consulting a group list stored on the PTT server to identify a plurality of receiving clients associated with the talking client; sending the PTT invitation message from the PTT server to the plurality of receiving clients; the PTT server receiving acknowledgement of the PTT invitation message from one or more of the plurality of receiving clients; the talking client pushing the “Talk” button to send a unicast RTP token-request to the PTT server; the PTT server translating the unicast RTP into a multicast RTP token-request; and the PTT server broadcasting the multicast RTP to receiving clients; wherein when more than one clients push the “Talk” button at the same time by send the token-request unicast RTP packet to the PTT server, the PTT server acknowledges only one client by translating the unicast RTP to multicast RTP and then broadcasting to all clients, and after comparing the receiving multicast and generated unicast RTP packets, only the client that generated the request RTP can further send-out talk burst unicast RTP, where the PTT server receives the burst unicast RTP and translates it into multicast RTP broadcasting to all clients.