An optimized call routing technique using session initiation protocol

Revolutionary changes took place in the modern communication world. Mobiles and internet have changed the way people communicate with each other. Nowadays every busy person has many devices for communicating with others such as a mobile phone, a telephone and a PC at his home, a telephone and a PC at his office etc. People call using a telephone or PC to communicate with that particular user according to their convenience (using the device which is along with them). But the user may not be present at that particular device. Hence the user may have to loose some calls. Those calls may be very important or urgent calls. This paper ICR aims to solve the above problem. In order to avoid this problem we should route the call to the current user location irrespective of the device used by the other user. We check the current location of the user and route the call to that location. For this we maintain a schedule for every user in the database provided in the server of the service provider. Whenever call comes to a particular user it checks the schedule of that user, finds his location and routes the call to that location. Hence this application can also be called as Schedule Based Calling. For implementation of this application we require a protocol which works for all the devices in order to create a session between any two different devices. Hence we use Session Initiation Protocol (SIP). Session Initiation Protocol is an application layer control signaling protocol used to create (initiate), modify and terminate sessions. Session represents the type of data transfer between two devices such as audio, video etc. SIP only initiates, modifies and terminates sessions. It does not provide any information about data transfer. Data transfer is done using other protocols such as RTP, RTSP etc. type of session is defined by Session Description Protocol (SDP).