VOIP Monitor & Analyse System Implement

Since the earliest implementation of Internet Phone by VocalTec from Isreal in 1995, much progress has been made on VOIP technology and it has had much impact on the traditional voice business of telephone companies. According to the statistics from the Ministry of Information Industry, the volume of IP Phone service has the surpassed the 152,833 million minutes in year 2005 in China.As a new telecommunicaion mechanism, VOIP not only has huge impact on traditional business of telecom companies, it also poses as a new challenge to the supervison deparments. Supervision deparments mendate new technical requirements based on the need of national security. Facing the rapid development of the VOIP phones, it's still a new area in China on how to supervise them.This thesis analyzed and designed an Analysis and Supervision System capable of monitoring gigabit-Broadband IP networks or trunks with even higher capacity, through pattern filtering, signal analyse and rebuild, stream rebuild and replay, and statistical functions. The system was tested by China Telecom and China CNC with sucesss.The thesis includes five chapters. The first chapter introduces of VOIP technologies currently used in China, the basic structure of VOIP supervision systems, and the problems need to be solved. The second chapter contains the analysis of the hardwares and softwares used by the front-end filtering system and the CFG algorithm that implements the fast pattern filtering. The third chapter analyzes signaling protocols, such as SIP and H323, and the BM fast-search-algorithm, used for recognizing variant protocols, is explained in details. In the fourth chapter describes methods for media stream data analysis and rebuild, and a highly efficient Hash alrgorithm was introduced for media stream data analysis and rebuild. The fifth chapter is the conclusion of the thesis, and points out the next step for further research.Throught a passive tap, the system implements realtime analysis, rebuild and statistics of VOIP traffic (including H323, SIP, QQ, ET263, MSN). The system meets the requirements of monitoring current VOIP business.