Technical Implemention Of Ethernet Shared Ring Based On SDH System

Owing to its simplicity, scalability, high reliability and low cost, Ethernet has become a widely used network protocol, and has taken possession of the leading position in LAN applications. However, due to its limited transmission distance, Ethernet is not suitable for long-distance transmission. And its weak performance monitoring and fault location capability cause some limitations of application. In WAN area, SDH is proved to be the most reliable and efficient technology, which backbone transmission rate has reached Tbps, therefore SDH is expected to carry Ethernet services. The EOS (Ethernet over SDH) specification, ITU-T X.86 recommendation was approved to achieve the Ethernet transmission over SDH.This thesis develops a 10/100M share-ring Ethernet module based on combination of EOS and Layer-2 switch for a 622M/2.5G SDH ring network, which employs MSTP technology and is applied on private networks in transport, electricity and other industries.The hardware design scheme is given at first, the function requirements of major sub-modules are introduced and choosing of keyed chips is analyzed. And then, the detail design of circuit is described, which includes detailed analysises and implementation methods of sub-modules. The key technologies, difficult issues and solutions to them are illuminated. The multi-level protection mechanism of EOS service, circuit board hot swap scheme, UPM based chip interface accessing method and electromagnetic interference problem are discussed for emphasis. At last, the results of performance are given, which indicates that the packet loss, throughput and latency match the designing requirements of the system.As a part of the SDH system, the 10/100M share-ring Ethernet module has been working well. The implement scheme of this module achieves a certain extent of practical significance to implementation of Ethernet over SDH.