A Review of Performances, H.323 Verses SIP on Voice over IP

The strength of people use talking over Internet is growing fast and extensive use of IP over telephony can be observed everywhere. According to a speculation, overall VoIP market will become a multi-billion dollar business within three years (Yuval Boger, 2003). While many corporations have been using voice over Frame Relay to save money by utilizing excess Frame Relay capacity, the dominance of IP has shifted most attention from VoFR to VoIP. Service providers are deploying packet telephony technologies as an alternative to traditional circuit-switched telephone networks in order to shift traditional voice services to packet- based networks and to create new services that combine data, voice, and video. The lower cost associated with converged data and voice network has been a prime driver for deployment of packet telephony, resulting in reduced long-distance bills. New companies are coming up with software supporting multimedia application on PC. Current paper is an attempt to observe two popular standards, H.323 and SIP, for its potential use for VoIP and compare their performances on the basis of architecture and the mechanisms they follow. It has also been intended to explore whether can they be used together to enhance the overall quality of service, signaling and security. Including the main protocols they use, their applicability, implementation, and Prospects have also been investigated. Some of the main protocols have been studied. Both the H.323 and SIP are distributed in nature and are open in that they are interoperable with different standards. Therefore their interoperability has also been discussed and compared. Though these standards are aimed for multimedia over IP and facilitate integrated transmission of video, audio and data, our main concern is related to voice over IP in this paper.