Patent ID: 8441962

Claim:
A method carried out by a communication device, wherein the device normally disregards incoming Real-time Transport Protocol (RTP) media if the device has not engaged in session setup signaling to set up a session in which to receive the RTP media, the method comprising: receiving, by the device, a Session Initiation Protocol (SIP) INVITE from a calling party seeking setup of a call between the calling party and the device, and engaging, by the device, in responsive SIP communication with the calling party so as to then complete setup of the call; making a determination, by the device, of whether the device receives from the calling party a Real-time Transport Protocol (RTP) call announcement media stream for the call; if the determination is that the device receives from the calling party an RTP call announcement media stream for the call, then playing out, by the device, the RTP call announcement media stream as a call announcement to a user of the device without the device having engaged in session setup signaling to set up a session in which to receive the RTP call announcement media stream, including without having yet transmitted to the calling party a response to the SIP INVITE, wherein if the device begins to receive the RTP call announcement media stream and has not yet received the SIP INVITE for the call, the device buffers the RTP call announcement media stream as the device awaits receipt of the SIP INVITE, and (i) if the device does not then receive the SIP INVITE, the device discards the buffered RTP call announcement media but (ii) if the device then receives the SIP INVITE, the device begins to play out the buffered RTP call announcement media as the call announcement for the call; and if the determination is that the device does not receive from the calling party an RTP call announcement media stream for the call, then playing out, by the device, a default call announcement to the user of the device.