Preemptable MAC Design Based On IEEE 802.3br Protocol

With the development of network technology,the Internet has been widely used in industrial control.The Industrial Internet requires lower latency,less jitter,lower packet loss and lower error rates during data transmission.Time Sensitive Network(TSN)provides important network quality of service(QoS)guarantee for real-time reliable transmission of industrial Internet.In time sensitive network,traffic scheduling plays an important role,and the IEEE 802.3br protocol provides a frame-preemptable scheduling scheme for time sensitive network.Therefore,the realization of the frame preemption function of the IEEE 802.3br protocol is of great significance for the development of time sensitive network.Firstly,this thesis studies the IEEE 802.3br protocol in detail,analyzes the format of the Ethernet preemptable frame,the conditions for frame preemption,and the process of frame preemption in the protocol,and proposes the preemptable media access control(MAC)model of this design according to the protocol.Then,design the overall architecture of preemptable MAC,including four modules: eMAC(express MAC),pMAC(preemptable MAC),MAC merge sublayer and reconciliation sublayer(RS).In order to handle traffic of different priorities separately,the MAC based on traditional Ethernet is divided into pAMC and eMAC.eMAC is used to process real-time data services and pMAC is used to process non-real-time data services.In order to achieve the function of frame preemption,the MAC merge sublayer is introduced between the MAC layer and the RS sublayer,which is the core and key point of this design.The RS sublayer is used to handle interface form conversion.According to the function of each module,the sub-module division and the detailed design of the hardware circuit were carried out.After the design is completed,based on Universal Verification Methodology(UVM),a verification platform is built to perform functional simulation verification,and field programmable gate array(FPGA)is used to test performance.Verification and testing results show that the preemptable MAC designed has the function of frame preemption,which can greatly reduce the delay of real-time Ethernet frames.And when the preemption function is closed,the function of the traditional Ethernet MAC can be realized.This design can achieve a bandwidth of 1Gbps at a clock frequency of 125 MHz.The preemptable MAC based on IEEE 802.3br protocol designed and implemented guarantees the real-time nature of high-priority data transmission,and can be widely used in industrial control,vehicle network,power industry,5G communication and other fields.