Using Web services for application development in Internet telephony: A case study on conferencing in SIP networks

Applications offered to end-users as value-added services are a critical element for the success and the survival of Internet telephony service providers. Some service creation frameworks have been proposed by IETF while alternative frameworks have been proposed by other forums such as Parlay and JAIN. All these frameworks have several drawbacks which may be solved by the use of web services. Web services are self-describing, modular business applications that expose the business logic as services over a network, generally, the Web. This thesis presents a case study on the use of web services to develop conferencing applications in SIP networks. The case study involves the definition of comprehensive web service interfaces that make conferencing capabilities available to developers. It also involves the implementation a sub-set of the interfaces as a gateway using SIP servlets, the development of two applications using the interfaces, and performance evaluation. The applications we have developed consist of dial in and dial out audio conferences. The interfaces proposed offer a level of abstraction that is higher than what the standard frameworks provide. In addition, their use does not require a background in telephony or telecommunications. This could allow developers who are new to the telecom field, to easily integrate conferencing capabilities to their applications. Furthermore, a considerable reduction of the application footprint is achieved. This reduction saves time and effort for application developers. These benefits make web services an interesting approach, despite the overhead introduced.