Research On Time-Triggered Ethernet Switching Technology

Along with the development of avionics towards distributed integrated modularization,Avionics system needs a reliable and real-time comprehensive communication network.On the basis of traditional Ethernet,Time-Triggered Ethernet increases the concept of timetriggered,and provides a conflict-free,deterministic network for the key control data services in the avionics system by planning the scheduling timetables.This paper analyzes the switching principle and demand of Time-Triggered Ethernet,focus on the two key technologies of the network switching,1)designs and implements a switching unit that can simultaneously support time-triggered service and traditional Ethernet service,2)designs and implements a scheduling timetable generation algorithm.This paper first introduces the research background and the basic idea of Time-Triggered Ethernet and introduces the concept of time-triggered.Secondly,by analyzing the switching principle of Time-Triggered Ethernet,it is shown that the two key technology of switching is to build the specific switching unit and design scheduling timetable generation algorithm.Third,a switching unit that can simultaneously support time-triggered services and traditional Ethernet services is designed,and an architecture of switching unit based on dual plane is introduced,and the working principle,module division and switching process are described.At the same time,the characteristics and advantages of this design are analyzed.Fourth,the detailed design and implementation of the input dispatcher module,scheduling module of time-triggered switching plane,processing module of time-triggered switching plane and output interface module are focused on,and the correctness and reliability of the module function are verified by simulation.Fifth,a time scheduling table generation algorithm is designed.The algorithm has the advantages of high efficiency and decreasing the transmission delay of key control data.The idea and workflow of the algorithm are introduced in this paper.Sixth,in the Time-Triggered Ethernet system,the designed switching unit and scheduling timetable generation algorithm are verified.Through the actual network environment and operating parameters,this design can further prove that this design can meet the Time-Triggered Ethernet switching demand.The innovative points of this article include,First,an architecture of switching unit based on dual plane is designed,which not only provides high real-time performance for time triggering services,but also complete the switching functions of traditional Ethernet services.At the same time,the switching unit can switch data between different speed ports.Second,in the switching unit,a method to improve the deterministic time of the data reception is designed,and the dynamic elastic delay is introduced to the time-triggered service frame inside the switching unit to offset the delay uncertainty caused by the frame transmission in the upstream path.Third,a scheduling timetable generation algorithm is designed.The generation time of the service is used as the parameter of the algorithm.The data can be sent immediately after production,shorten the waiting time and improve the real-time transmission.