Optical Synchronous Digital Transmission Network Design, Fpga-based Eos System

SDH(Synchronous Digital Hierarchy) is now applied worldwide in metro area network,communication network and wide area network. Owing to its major advantages such as synchronized duplication, standard optical interface and mighty management function, SDH network has become the backbone of communication network. Ethernet has become the first choice in various data business because of its obvious advantages of low-cost,agility, etc. EOS(Ethernet Over SDH) is an important research area in transmission technology. This paper introduces a design scheme of transmitting Ethernet over SDH by GFP encapsulation.This paper begins with the brief introduction of SDH fundamental,Ethernet principle and three popular encapsulating protocols, i.e.PPP(Point-to-Point) ,LAPS(Link Access Procedure-SDH) and GFP(Generic Framing Procedure).After making comparison and analysis of the three data encapsulation protocols, it summarizes the benefits of GFP. Then it presents the whole design scheme of EOS system and describes in detail the implementation and design of two main modules such as GFP encapsulation and VC-4 multiplexer.This system adopts the design method of Top-Down which is used broad in IC design today, and uses hardware description language Verilog as tool to design the circuit modules. Then these modules have been processed function simulation with ModelSim of Model corporation, and been synthesized with Quartus II of Altera corporation, then the verification of FPGA with these modules is done in the platform of Altera FPGA device (Cyclone series).