Design Of VAR Mutil-Services Optical Transmission And Switching Intergrated System

For the purpose of realizing large-scale and high quality monitoring,conforming to the monitoring system trend of digitization,service diversification,function integration,and modularization,OB telecom Ltd.put forward a new system named "VAR multi-services optical transmission and switching integrated network",one of the key technology is high quality switching for real time data.Based on the VAR platform,the author studied various key technologies of current high speed switch system,and realized the design method.The contributions can be outlined as follows:Firstly,advantage and disadvantage of Circuit Switching and Packet Switching are studied, and then depending on VAR business’s characteristics,a new method basing on packet transmission technology and Circuit-switched technology is carried out,raising bandwidth rates while guaranteeing the QoS of video and audio.Secondly,characteristics of various switching cell are studied,especially,the theory of design Crossbar Switching Cell and the block condition of three-stage Clos Network,and then based on the characteristics of VAR data frame and the hardware resource structure,using non-internal blocking Crossbar Switching Cell to construct a Rearrangeable Nonblocking three-stage Clos switching sub-system.Thirdly,for a more complex situation of routing in the FPGA implementation,the method of distributed processing is used,which comes up with that routing computation is completed by CPU controller,controlling switching card through back-plane RS485.It simplifies the design on the condition that system functions are realized.Finally,complete switching-card’s circuit design and design functional structure frame of switching sub-system,transform it into logical language and then give VDHL implementation code and functional simulation chart of main modules.Finally the design of switching sub-system is finished and the real effect of the system is got.