Time-sensitive Network Best-effort Traffic Timing Rearrangement Scheduling Algorithm

Time-Sensitive Network is currently a communication technology being actively promoted by the international industry.It is based on standard Ethernet and uses a series of key technologies such as high-precision time synchronization,traffic shaping,path control,resource reservation,and business scheduling.It provides reliable data transmission guarantee for real-time sensitive business and is widely used in industrial control,vehicle network,aerospace and other fields.Therefore,research on Time-Sensitive Networks is an important work.Based on the study of the key technologies and standard protocols in Time-Sensitive Networks,this paper,through an in-depth study of the IEEE 802.1 Qbv protocol and guard band mechanism,clarifies the root cause of the waste of bandwidth resources,in order to solve the problem of waste of bandwidth resources,Respectively,proposed algorithms for best-effort traffic(BE,Best Effort Traffic)scheduling for three scenarios,aiming to improve the bandwidth resource utilization of best-effort traffic time slots:(1)Re-arrange the transmission sequence of the BE frames in the buffer,and no longer follow the first-come-first-served principle,so that the new transmission sequence can maximize the bandwidth resources of the current cycle best-effort traffic time slots.When re-sequencing the best-effort traffic,establish a mathematical model for maximizing the utilization of time slots bandwidth resources at the beginning of the best-effort traffic time slots,and a group of frames that maximizes the utilization of the bandwidth resource of the current time slots is obtained,and complete the transmission of the selected group of frames in a certain order.(2)Considering that there will still be new BE frames arriving in the buffer during the transmission of BE frames,the newly arrived BE frames can be taken into consideration to expand the selection range of BE frames that maximize the utilization of time slots bandwidth resources.Thereby,the bandwidth resource utilization rate of the best-effort traffic time slots is further improved.In this process,every time a BE frame is transmitted,a mathematical model that maximizes the utilization of the remaining time slots bandwidth resources is re-established for all BE frames in the buffer,and a set of frames that maximizes the utilization of the remaining time slots bandwidth resources is obtained,and determine the next BE frame to be transmitted in order.(3)When the above-mentioned method is used to rearrange the transmission sequence of best-effort data frames to maximize the time slots occupation,some BE frames cannot be selected for a long time and cannot receive transmission services,and the retention time in the buffer is too long.In response to this problem,the paper adds a maximum delay guarantee mechanism on the basis of the proposed algorithm,and prioritizes the BE frames that have been in the buffer for too long,and then processes the remaining BE frames.The added maximum delay guarantee mechanism is at the expense of bandwidth resource utilization,which can reduce the maximum queuing delay of BE frames in the buffer.(4)Introducing a preemption mechanism into the IEEE 802.1 Qbv protocol can guarantee the transmission of high-priority traffic while reducing the waste of BE time slots bandwidth resources caused by the guard band.This paper introduces a preemptive mechanism into the best-effort traffic scheduling algorithms proposed in the above three scenarios to form a preemptive best-effort traffic scheduling algorithm,which can further improve the utilization of bandwidth resources.