| Recent days have witnessed rapid development of telecommunication market in China and the honor of its great fulfillment and integrated telecommunication abilities. With the amalgamation between telecommunication fields, however, telephone network, computer network and cable-tv network trends to merge and network has to face more and more pressure and versatility of its operation demand. ISPs have to provide more and more data and multimedia services which, however, could not be provided by PSTN to keep their enterprise users. At the same time now, especially after the breakout of broadband bottleneck when email, ERP, SCM, EC and other services which are based on data procedures have became part of life, users'telecommunication demand has varied a lot compared with the era when internet was not very popular. The integrated services based on data & data, data & voice, data & video, video & voice have become the future tendence. NGN has utilized the merged technique which can provide integrated voice, data, video and multimedia with excellent opening characters and availability to expand services. It has totally changed the single-service network and its marketing methods and definitely cut down the expenditure of the network construction and reconstruction. Therefore, it is a worthwhile subject that how could a telecommunication enterprise build a integrated net based on the core of ip network which could provide voice, data, video and could evolve to NGN smoothly.Based on the studies on the architecture, evolvement pattern,characteristics,and softswitch technology of NGN, we demonstrated that softswitch technology dealing with the separation between services and network, and separation between call control and bearers was the foundation of NGN development. Meanwhile, a practical evolvement solution for constructing metropolitan NGN under the conditions of present network was put forward. A solution for Metropolitan Integrated Service Network (NGN) aimed at NGN based on softswitch technology was introduced, according to the actual status of the network of Jilin Unicom ChangChun Branch. This solution will conduce to integrating various services including voice, video, and internet etc. within metropolitan region by uniform platform of service and network based on existing metropolitan bearer network. NGN is composed of the following three parts: (1) Integrated Service Bearer Network: The various services were carried by the same network platform using the existed metropolitan bearer network , and QoS guarantee was provided according to requirement. Furthermore, metropolitan bearer network based on ATM/FR technology, IP metropolitan bearer network with QoS guarantee, and SDH metropolitan transmission network can be adopted, respectively.(2) Integrated Service Equipment: it is composed of SACP(service access control point),CCM(call control manager),GW(gateway),BRAS(broadband remote access server), etc. Integrated Service Equipment implements local integrated service, interworking of each backbone service network, and to realize access control of each terminal user within CPN(customer premises network).(3) Integrated Service Operating and Support System: a set of operating and support system should be supplied for each metropolitan integrated service network. Operation and maintenance of local metropolitan integrated service network and the interface with existed service operating and support system of UNICOM were provided, respectively.Operator provides integrated service of integration of voice, data, image, and video within metropolitan region to attract old clients with new services and new clients with more services by constructing toward NGN and Softswitch technology, so that competitive and diverse services are introduced in quickly. The above-mentioned measurements can effectively improve creativity of communication network, and solve bottle-neck of service innovation.Technical difficulty of the research on NGN is how to achieve telecom-level controlable, administrable, and calculable of network billing. Therefore, the concepts of CCM and SACP were brought forward in NGN solution. SACP located at convergence POP of NGN and made service network in relation with bearer network. SACP took over command issued by control layer of service network, and controlled directly channels and resources of various media stream. CCM situated at control layer who controlled the access of clients by SACP, and supplied with dynamic control over channels and resources of various services accessed. By the relation between service control layer and media bearer layer, the latter was controlled by the previous one, so that NGN could achieve telecom-level control and administration.The following solutions for some key problems were put forward during network design and engineering practice of NGN: the solution of solving terminal bypass problem in NGN aimed at supervising terminal user; the unitive solution for NGN网,backbone bearer network, and CPN pointed to QoS guarantee problem; the solution solving security problem in NGN and CPN; the solution for user firewall penetrated in CPN; the solution solving the problem of IP address in service project and NGN.NGN possesses the following service capacities and can provide a stable network base for coming service innovation and development by the constructing of NGN: local and long-distance communication in voice service or facsimile service; local and long-distance communication in video communication service; access of internet; interworking of voice service between video communication network and voice network; interworking of video service between video communication network and internet; supporting complementary service, value-added service, and intelligent service to voice network.By this research , we could say telecommunication enterprise could take advantage of its construction of NGN to make new telecommunication markets and profit spaces and thus form a new business model for ISP in the fierce diversity competition of telecommunication market. |
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