Service discovery & availability subscriptions using the SIP event framework

Discovery of available and suitable services is an essential piece within a service provisioning architecture. Numerous approaches have been proposed, standardized and deployed in the past. However, many of them either lack deployment (i.e., adoption beyond certain research labs or communities) or features (in particular in the area of visiting domain support, availability notifications, and disclosure authorization). The session initiation protocol (SIP) and its event delivery extensions promise a wide adoption in the Internet due to its fundamental importance for future session-based communication. Further, its adoption in the next generation of mobile devices will lay ground for a large-scale deployment of this protocol. This paper discusses the suitability of SIP events for service discovery by presenting a solution that provides many of the currently unsupported features. Deployments are proposed that would enable endpoint-based but also repository-based discovery, the latter aiming at integrating legacy systems into the solution.