Design And Implementation Of TSN Time-Triggered Streams Transmission Guarantee Mechanism Based On Linux

The enterprise intranet includes two parts: the management-oriented information network and the production-oriented control network.The two parts perform their respective functions and are isolated from each other,and it is difficult to realize the data exchange between the networks.Today,enterprises are vigorously promoting digital transformation,the above issues hinder the full flow and seamless integration of enterprise data.Therefore,breaking the enterprise intranet structure,integrating the information network and the control network,and realizing the unified perspective of the application platform is one of the most important technical requirements of the enterprise intranet.Time-sensitive networks are compatible with standard Ethernet and can customize transmission strategies according to different traffic transmission requirements.Timesensitive network standards define a variety of shapers for different traffic types,among which the IEEE 802.1Qbv protocol proposes a time-aware shaper that can provide deterministic transmission services for time-triggered traffic in time-sensitive networks.However,the IEEE 802.1Qbv protocol only specifies the basic working principle.Routing,resource scheduling,shaping methods,etc.are all open issues,and the related complete implementations are few.Based on the relevant standards in time-sensitive networks and the functions of the Linux operating system,this paper designs and implements a transmission guarantee mechanism for time-triggered traffic to ensure the deterministic transmission of time-triggered traffic.The transmission guarantee mechanism consists of three parts: a high-precision time-aware shaper,a data packet processing acceleration module,and a clock synchronization server.The design and implementation of the high-precision time-aware shaper is based on the IEEE 802.1Qbv protocol standard,and is mainly used to ensure the transmission reliability of time-triggered packets.The shaper identifies the time-triggered traffic during the forwarding process,and calls the time allocation algorithm to assign an ideal sending time to each packet according to the information of time-triggered traffic.Finally,it uses priority mapping to guide packets into the queue and uses the network card function to achieve deterministic transmission.The data packet processing acceleration module is mainly used to solve the problem of slow processing speed at the switches.The module converts time-triggered packets’ protocol type when forwarding them,deploys mapping rules at the switches entrance to distinguish time-triggered flow packets from other traffic,and uses separate CPU resources for processing to reduce the time-triggered traffic processing delay.The clock synchronization server improves the transmission priority of the PTP packets at the forwarding layer,and ensures the transmission quality of these packets.And the clock synchronization server implements a clock synchronization algorithm at the control layer.The algorithm integrates the best master clock algorithm and the shortest path algorithm.It calculates a reasonable clock synchronization configuration at the forwarding layer according to the network topology and device properties,and deliver and configure it on the switches.Finally,this paper tests the Time-triggered traffic transmission guarantee mechanism.The test results show that the high-precision time-aware shaper can well guarantee the transmission reliability of time-triggered packets,and complies with the IEEE 802.1Qbv protocol standard in function,and has certain advantages compared with other software implementations in terms of performance.The data packet processing acceleration module has obvious processing acceleration effect in the forwarding process of timetriggered traffic.The clock synchronization configuration results obtained by the clock synchronization server are reasonable and meet expectations.