Research On Gateway Call Authorization In Direct Way Of H.323 Protocol Stack In NGN Architecture

With the fast development of telecom and internet techniques .It is clear that telephone network and packet data communication network will converge into NGN (Next Generation Network) in the near future. As a key technique in NGN, Soft-Switch is widely being used in network. In NGN system architecture, Soft-Switch is being used as a open-system function entity and a domination center. It communicates with outer entities through sustaining multi-protocol, which includes H.248/MEGACO, SIP, SIGTRAN, BICC, H.323 protocol, etc. Further, as a main protocol between Soft-Switch and telecommunication network, H.323 protocol is much more widely being used.This thesis is mainly organized around gateway call authorization directly in H.323 protocol stack based on application of H.323 protocol in NGN architecture. Firstly, it describes Software-Switch technology in NGN. It also describes the appearance background of Soft-Switch technology, the concept, architecture, function and main application protocols of Soft-Switch technology. Secondly, we present the H.323 protocol and SIP protocol, which are widely being used in NGN. And we simply compare H.323 protocol with SIP protocol in complexity, extension, service application and supplementary service ability. Finally, we put forward a question for discussion and describe its actualization in NGN architecture. We particularly describe in some aspects, including the current application of H.323 protocol, the resolution project, the academic network frame and the material realization.Through the actual application in current network, it is clear that gateway call authorization directly in H.323 protocol stack based on application of H.323 protocol in NGN architecture is widely used. It presents that it has a simple network, comparing with the current application network. It also adopts software instead of hardware in realization, which is benefit for retrenching the expenditure, improving benefits and satisfying the needs of the production operator. It is content for the actual application.