Metropolitan Transmission Network Optimization Of SHEN YANG Network Communications Co.

As a support of various service networks, the metro transmission network of Shenyang Netcom has made a great progress. Along with the development of telecommunication technology, the transmission network will be transformed into a platform upholding integrated services from the original supporting network. In order to satisfy the demand of rapidly-developed new services better, it is essential to optimize the existing transmission network. Aiming at the diversified services of current metro networks, the paper introduces the technology of metro optical transmission network, analyzes the characteristics and application scope and explains the optimization program of Shenyang Netcom metro transmission network in light of the actual situation and the forecast of services development.1. Introduction of the Technology of Metro Transmission NetworkCurrently, the technologies applied in metro transmission network mainly cover multi-service transport platform (MSTP) based on synchronous digital hierarchy (SDH), resilient packet ring (RPR), metro wavelength division multiplexing and automatic switched optical network (ASON).1) MSTP technology provides a variety of interface and protocol. With the capability in bandwidth management and aggregation, it can achieve point-to-point and point-to-multipoint data transmission and have definite advantage in network environment that require both voice and data. For such traditional operators as Shenyang Netcom, the multi-service transport platform (MSTP) based on synchronous digital hierarchy (SDH) is their focus of application.2) RPR technology is more suited to the network environment that takes data as the main part and TDM service as the supplementary. As means of networking of small and medium-sized cities, it is particularly fit for new operators to develop in competitive regions. However, its limitation in only supporting the ring network and relatively simple network management system restricts its application.3) The greatest challenge faced by metro wavelength division multiplexing technology (WDM) comes from the cost. With the intensification of telecommunications competition and the increase of service types, the metro optical fiber shortage will become more and more common, and WDM application will be greatly improved. But the maintenance complexity and cost still restrict its application.4) ASON technology is still at the development stage. Some standards for which are being developed and perfected, only few operators utilize intelligent optical network devices, for the time is not yet ripe to carry out large-scale application of such devices. Therefore it is advisable to combine with service development needs and network evolution to introduce ASON technology.In view of the above-mentioned characteristics of transmission technology and the actual situation of Shenyang Netcom, it may be considered to adopt the hybrid networking technology, i.e. the co-existence of multiple network technologies; give priority to the use of SDH or MSTP technology in...