Improving 'Presence' Situation in the SIP Based IP Telephony Networks

摘要

The convergence of Voice and Data networks has changed the rudiments of telecommunication. With the spread of Cellular networks, convergence of voice, data, and cellular network is envisaged allowing users to seamlessly access services across networks while on the move. In this paper we discuss problems related to “Presence” in a converged network. A key issue in presence is to trace a user correctly and consistently. In a SIP (Session Initiation Protocol) based IP telephony network the presence information is kept as “Registration” bindings. We propose to use an alert mechanism, similar to paging in mobile network to notify the user of expired SIP registrations, so that the device/user can update the registration bindings. This improves the overall functionality of a SIP based IP telephony network and allows users to receive calls that would have otherwise been missed. In case the call does not mature, we inform the called party about the missed call so that the conversation can mature asynchronously. This solution would increase the reach of VoIP (Voice over Internet Protocol) to people and regions where internet penetration is low.