The use of resource list servers in IMS presence for developing networks

The IP multimedia subsystem (IMS) is a next-generation service delivery platform that enables operators to deliver services such as multimedia and IP content to both fixed and mobile users. One of the important services for early adopters in the IMS is presence, an application well-known on platforms such as the Internet, which can be integrated into other applications as an enhancement. A major constraint to the implementation of IMS services over developing networks is the requirement of significant bandwith, especially over the ¿last mile¿ access network, for the delivery of multimedia and associated data. However, the availability of broadband network access for multimedia services in rural and developing areas, particularly in South Africa, is very low. The resource list server (RLS) is important to the IMS presence application, as it optimises the management of intensive presence signalling, and aggregates information to subscribers from within the IMS core network. The use of an RLS can reduce the demands of the IMS Presence application on constrained access network resources.