The University of British Columbia

Conventional network services operate like silos in that a specific set of services are offered over a specific type of access network. As access networks evolve to provide IP-based packet access, it becomes attractive to break these "service silos" by offering a converged set of IP-bascd services to users who may access these services using a number of alternative access networks. This trend has started with 3d generation cellular mobile networks, which have standardized on the use of the IP Multimedia Subsystem (IMS) to manage user access to a wide variety of multimedia services over the mobile Internet, while facilitating interworking of heterogeneous wireless and landline access networks. This paper reviews the function of the IMS, and presents the use of the Service Oriented Architecture (SOA) above IMS to further enable service convergence. Examples of converged services are presented. Technical challenges in network and service convergence are discussed and some recent results are presented.