Extending CPL with context ontology

Communication has always been an essential part of people’s everyday life. Nowadays most of people would like to be reachable on multiple devices at anytime, anyplace. As a consequence, there has been a need to know and exploit a user’s availability for communication (so called presence information), so that he/she can control incoming calls and make the decision to accept this call or not based on the user’s current context. The appearance and acceptance of Session Initiation Protocol (SIP) as a signalling protocol for next generation networks has opened the door for multiple services, such as Voice over IP (VoIP), chat, games, instant messaging, and other innovative communication services. Built on top of existing data communication networks, this has enabled easy integration of voice and data services. In this paper we present an idea on how to use the context information to enhance the power of existing SIP call control services, to enable users to have greater control over their incoming/outgoing calls. These services are implemented using Call Processing Language (CPL), a language to describe and control Internet Telephony Services. They are extended with context parameters to permit context-based decision making based on context ontology. We want to show how easy is to add new context parameters to the CPL and how complex criteria can be built using our solution.