Establishing real time multimedia session amongst multiple devices with election of relaying control and media service devices

摘要

Existing systems (eg. the Internet Protocol Multimedia Subsystem (IMS)) establish and provide services/sessions using central servers. The invention discloses a system wherein devices wishing to participate in a session calculate capability scores based on their hardware capabilities and network quality of service characteristics and submit them to a moderator (which may be one of the participating devices). Based on the capability scores an application service device and a media service device are selected. The application service device establishes SIP connections to all other participating devices to receive and forward control information. The media service device establishes RTP/RTCP connections to receive and forward real-time multimedia streams. Preferably the device with the highest score is selected as the media service device and that with the second highest score as the application service device. If none of the devices is capable of fulfilling application/media service duties, the system can select central application/media servers to the role.