Local SDH transmission network design

We know that today's society is the information society. The highly developed information society requires that the communication network can provide a wide variety of telecommunication services. The amount of information transmitted, exchanged and processed through the communication network will increase, which requires the modern communication network to be digitalized, integrated, intelligent and personalized. The transmission system is an important part of the communication network, directly restricting the development of the communication network. One of the most important developments in the world to develop the information superhighway, with one of the key is to set up a large capacity transmission fiber network, continuously improve the transmission line on the signal rate, widening the transmission band. It is like expanding capacity to accommodate a large number of traffic in highways. At the same time the user wants the transmission network to have a worldwide interface standard, to access to global village, in where every user can easily communicate anytime and anywhere. Synchronous Digital Hierarchy (SDH) is a comprehensive information transmission network that integrates multiplexing, line transmission and switching functions and is operated by a unifi ed network management system. It is a synchronous information transmission network developed by Bell Communication Technology Research Institute's optical network (SONET). The International Telegraph and Telephone Advisory Committee (now ITU-T) received the SONET concept in 1988 and renamed it SDH, making it a general technology system that applies not only to fiber but also to microwave and satellite transmission. It is applied for eff ective management of network, real-time service monitoring, dynamic network maintenance, interoperability between different vendors and other functions, greatly improves network resource utilization, reduce management and maintenance costs, flexible and reliable and efficient network operation and maintenance. So it is in the center of attention in world's information fi eld of transmission technology development and application.