Compare and contrast the technologies currentlly employed for implementing Voice over IP in corporate network

From last two decades the development in the field of Telecommunication and by the birth of VoIP has totally revolutionized the voice transmission over copper mediimi. With regard to the economic aspects, the packetization of voice using Voice over IP has given rise to new international telecommunications carriers. These carriers have distributed network architectures using the Internet as a platform. VoIP networks have an architecture offering the most efficient way to implement multilateral telecommunications agreements, thus eliminating the need for carriers to engage in hundreds of bilateral traffic agreements as is required between traditional circuitswitched PSTN carriers. The primary benefits of deploying VoIP are cost saving, cost reduction, and ability to provide enhanced telecommunications features, functions and applications. Businesses can achieve financial benefits form VoIP through reduced upfront capital expenditures for installing converged network, ongoing cost saving for a single managed network which provides voice and data service together and the opportunity of second tier carriers which offer cheap long distance phone calls to users. Since the birth of VoIP two main standards have emerged for signalling and control for the transmission of voice over packet network: ITU-T H.323 and the IETF Session Initiation Protocol (SIP). These protocols almost provide same end-to-end services and signalling function with different approaches.H.323 was first developed to work on ATMs for multimedia transmission. Later it was enhanced with additional functionality to support end-to-end voice transmission. Where as SIP was developed keeping in mind the exact requirement for voice transmission with less overhead. Although H.323 is slightly complex suite of protocol, it is widely deployed by vendors. ITU-T group is has enhanced their research to make H.323 more simpler protocol While lETF-SIP is already favours a lightweight approach based on HTTP with less complexity . Most of the current vendor's development supports SIP because of its simplicity. 5DEPARTMENT OF COMMUNICATION & ELECTRONIC ENGINEERIN