The Improvement And Implementation Of Gatekeeper Software Based On H.323

In recent years, Internet telephony or voice-over IP is attracting an increasing amount of attention for the reason that it has the potential to significantly reduce the cost of long-distance voice communication.The entities that provide multimedia communications services over Packet-Based Networks(PBN) are described in H.323 recommendation.The topic of this paper is based on GnuGk(GNU Gatekeeper) open source project,it is the summary of improvement and implementation of gatekeeper system based on H.323 protocol.Chapter 1 introduces the source and significance of thesis and main work done by author.In chapter two,VoIP and related technology is generally introduced. After discussing the develop history of IP telephony in brief, it is introduced that how to code/decode the voice,control the signaling and transmit the voice effectively.Finally the structure of H.323 system and protocol stack is given.The chapter three mainly focuses on requirement analysis, design and implementation about how to improve gatekeeper function and performance. First this part introduces the basic functions of the gatekeeper, H.323 protocol process, the demand for new features to enhance the performance requirements and developing enviorment. Second, according to the results of requirement analysis, the general design principle,module architecture, the static class structure,thread dynamic running structure are described in detail.Finally, based on the results of general design,it is introduced that the design and implementation of gatekeeper RAS signaling message, the call processing module, the disposition of registration and call table, the communication between the database management module of gatekeeper and MySQL database, the call signaling process thread,and the general system thread structure in order to improve the performance.The next chapter the related test of the gatekeeper is described. First, the gatekeeper functions were tested and the results meet expectations. Then it is introduced that the performance of the gatekeeper test environment, tools, process. Finally, the cause of performance test result is analysed and the preliminary conclusions are given.The last part of this paper summarizes the present work and put s forward the further research work.