Context-based applications in converged networks: Beyond SIMPLE presence

The article presents a large-scale presence virtualization and federation platform that federates across heterogeneous presence domains, letting applications exploit cross-domain contextual data. With the emergence of unified communications (UC) in converged networks, distributed presence data is available for context-aware applications. Rich communication services (voice, text, video, and conferencing) are provided over the Internet, through a converged telephony and the IP-based network infrastructure, using a new set of protocols and protocol architectures in particular, the Session Initiation Protocol (SIP). SIP can set up and manage contextual communication sessions, aided by a widely standardized publish-subscribe event system, called the System for Instant Messaging and Presence-Leveraging Extensions (SIMPLE).