Spanning a multimedia session across multiple devices

This paper describes an innovative solution that allows a multimedia session to be distributed over multiple devices that are in the close proximity of a user. This would typically be useful when a user engaged in an audio/video conference enters a meeting room. Upon entering, all media session components are transferred from the PDA to the projector, HiFi-set and webcam present in the meeting room. When the user leaves the room all media session components are transferred back to the PDA. Transferring parts of a multimedia session between different devices is defined as partial session mobility (PSM). Numerous methods exist for PSM. None of these methods is directly suitable for initiating PSM from a dedicated network node such as an IMS Application Server, but do provide a starting point. Because of a number of advantages in the invite-based method, this method is taken as basis for network-initiated PSM. This paper compares the existing methods, describes the proposed network- initiated method to support PSM and how to combine it with terminal-initiated PSM. It also describes how PSM could be supported in IMS.