| A good metropolitan network should be a general transmission platform, which can carry out kinds of services efficiently and reliably. So it is necessary for facilities in metropolitan network not only to support TDM but also to support various data interfaces, optimize data transmission efficiency, bring down the transmission cost per bit and meet the increasing requirements for data services transmission, accordingly enhancing the investment benefit for metropolitan network. Because the capacity and interface of traditional metropolitan network can't satisfy the requirements in service transfering and gathering, which has become the bottleneck of service providers.This paper analysis the application problem in metropolitan network, and the disadvantage is as follow: due to the fast development of digital services, metropolitan network must provide the digital services efficiently. Meanwhile services of voice and special TDM line are still the main income for company. How to support the fast increasing digital services in addition to ensure TDM transmission becomes appeal to metropolitan network. We put forward the new idea for constructing metropolitan network: on the basis of protecting old investment on network, we can apply new technology to enhance the capacity of bandwidth. It can ensure TDM transmission and support various digital interfaces, enhance digital transmission efficiency. Through investigation in technologies of transmission system equipments such as SDH, MSTP, DWDM loop network, CWDM, RPR and so on, we analyzed the traits of metropolitan network and its trend. We have a conclusion: MSTP over SDH is one of the most achievement mode now. This idea is applied in construction of metropolitan network. In succession, we introduced the object of metropolitan network, basic demands, structure of the network and the fundamental of network organizing. Then, we combine long-time experience in constructing metropolitan network from TieTong and other companies. We summarize 3 models for typical network setting especially for extra big city, big city and town. Different network structure and technology should be taken based on the scale and the development stage of different cities and district. In the end, we carry on the plan of the network structure, the function, synchronized clock of the metropolitan network for YUXI district, and the mode of the protection for loop network in this area.At present, the project of YUXI transmission network has been implemented; the idea and principle in this article are incarnate sufficiently. And the facilities in YUXI... |
