Investigations On The Application Of Packet Transmission Network (PTN) Technology In Beijing Unicom 3G-oriented Metro Network

With the shrinking of TDM services and the maturation of "all IP environment", especially as 3G services launch, the existing circuit-switched transmission network can not meet the IP-based data services'carrier requirements, which requires transmission network to make the transformation. That is, the equipments have to transfer from "multi-service interface adaptation" to "multi-service core adaptive". Such packet requirements of the transmission network itself are raised by IP-based business. But meanwhile, it is also necessary to ensure that traditional services (such as voice) are of the normal operation, which means requiring the integration of both packet and transmission technology. Under the circumstances, packet transport network (PTN) comes into being. Currently, PTN is still under the way of standardizing, but the manufacturers have launched relevant equipments, major domestic carriers have begun to test them and even in some areas PTN network has been established. It can be said that an agreement has been achieved by operators, equipment manufacturers and industry experts:PTN will be the development direction of MAN in the future.Therefore, this text follows the pace and trend of PTN technological development closely, which introduces the origin of PTN, technology classification and development systematically and comprehensively, and pays an important attention to analyzing and explaining key technologies of the PTN, its scenarios, network positioning and deployment strategies, also some other key aspects.According to Beijing Unicorn's network status and the network's carried requirements of mobile, broadband and VIP customer, this thesis points out the pressure faced by the Beijing Unicom local transport network, and make a further explain on the necessity of building the packet transmission network based on the local transmission network.From the current status of Beijing Unicom local transport network and the real needs of PTN network construction, this article make a comparative analysis between PTN technology and the current techniques used in metro networks, draft a general framework of PTN network, and set the PTN Technology-led strategy and principles of network construction. On this basis, the Beijing Unicom integration program including the core, switching, backbone, network convergence and so on as well as network management system are discussed in detail, and the statistics of the Beijing Unicom current PTN network overall construction scale is also statistic in the thesis. Finally, the thesis makes a summary and outlook to the effect of Beijing Unicom current projects and the continuation development of future network.