Design Of Fast Ethernet Switch Supporting IEEE1588 Protocol

With the rapid development of industrial technology and network technology,the real-time performance of network becomes increasingly important,which requires higher clock synchronization precision in a switch.On one hand,ethernet technology is one of the fastest growing technologies in the industrial market.Because of its low cost,high maturity and flexibility,Ethernet technology has become the mainstream in ground LAN technology.On the other hand,the precision clock synchronization protocol for networked measurement and control systems,which is reffered to as IEEE 1588 standard,has reached sub-microsecond synchronization accuracy.It has a very good performance in representative and openness.Based on the laboratory research projects,a fast Ethernet switch which supports the IEEE1588 protocol is proposed to be designed.The hardware platforms of the switch and the IEEE 1588 clock synchronization technology is detailed designed and achieved.Firstly,this paper analyzes the characteristics of the IEEE1588 protocol and compares it with other clock synchronization protocols.The advantage of IEEE1588 protocol on improving network clock synchronization accuracy is described.Basised on this,the major factors of affecting clock synchronization accuracy is analysised simply.These factors including operating system and protocol stack,network components,instability of clock and resolution of clock.Then,the overall structure of the switch,the technical specifications and the design scheme of various functional modules are described in detail.Next,the hardware breadboard for the IEEE1588 switch is designed and achieved.Finally,the theory and key technology of the high-precision network clock synchronization based on IEEE1588 protocol is focused on.Used the clock provided by physical layer PHYTER"DP83640",the Sending and receiving time of IEEE1588 synchronization packets is marked accurately at the physical layer.Then the IEEE1588 protocol is verified on the FPGA development board.The network clock synchronization accuracy has achieved the sub-microsecond level by board-level tests.According to the result of the tests,the high-precision network clock synchronization technology is implemented and the sub-microsecond level is reached.So,the expected research goals is achieved.