Research And Realization Of Tandem Connection Monitoring In SDH

With the fast development of today's the telecom industry, all those providers' network has experienced construction and expansion for a long period; meanwhile they combine their sub-net and other providers'subnet into a large and united network. As a result, it becomes an important research subject to monitor the network performance and to locate the trouble quickly in the transmission technology.SDH (Synchronous Digital Hierarchy) is now widely used in Metropolitan Area Network, long-distance communication network and Wide Area Network throughout the world. The Frame structure for SDH arranges abundant overhead bytes for the operation, management and maintenance of the network. With these overhead bytes, the layer by layer specified management for STM-N is implemented. The Byte N1 in SDH provides Tandem Connection Monitoring function to the network, which is used to evaluate the quality of providers'network and monitor the quality of the network in the entire subnet or a certain path as well. With this TCM function, the source of errors and defects could be judged accurately, the argument among different network providers could be resolved, and the maintenance and management of the network could be more convenient.Through the encoding and processing way to the Byte N1 defined in G.707 Annex D, this paper decides the design target and overall plan, and then uses the hardware language to implement it in circuit. At last, I design the simulation platform to simulate this module and get the feasibility study report.The Chapter 1 of this paper firstly introduces the application background of TCM technology and generalizes the major chip vendors and equipment providers both domestic and abroad. The Chapter 2 briefly reviews the frame structure of SDH, analyses the two processing ways of Byte N1 that defined in G.707, and introduces the function of TCM technology. In the base of it, the Chapter 3 constructs the whole scheme of TCM module design, detailedly introduces the circuit design and implementation of the two major modules of TCM source and sink, and states the simulation strategy. The Chapter 4 precisely describes the design of the function module in TCM. It firstly defines the connection signal, and then introduces the design of the source module and sink module of TCM, and detailedly describes the design of BIP-8, B3 compensation and the design of CRC-7 circuit at last. The Chapter 5 designs the simulation system and simulates and verifies the important signals of TCM source and sink. The result shows that the indexes apply with the anticipation. The chapter 6 generalizes the whole paper.