Lightweight Conferencing Enabler for Multiparty Applications in the IMS

The IP Multimedia Subsystem (IMS) brings more functionality into communication networks and allows them to offer a range of services beyond the mere transport of media. IMS standard multiparty services include audiovisual conferencing and Push To Talk (PTT/PoC), which are powered by specific (and expensive) servers performing media handling functions in a centralized manner. These multiparty services mimic traditional telecommunication services and are specialized in audio and video conferencing. This approach lacks the flexibility to provide innovative multiparty applications that require custom media or distributed topologies. For example, an online game may include voice communication among players, but it requires additional means to communicate the game state among players. Applications of this kind have to rely on custom servers to provide multiparty functionality and would benefit from a common, media-agnostic, conferencing framework in the IMS. This paper focuses on providing generic multiparty functionality in the IMS by making the most of the XML Document Management (XDM) services: group management, event delivery and search functions. The paper describes a lightweight enabler implemented on top of the XDM that supports distributed applications in the IMS.