Research And Implementation Of Delay Guarantee Mechanism Based On Asynchronous Traffic Shaping

Existing Internet lacks latency guarantee capability which technology is no longer able to meet the real-time and deterministic requirements of latency-sensitive applications such as Industrial Internet,audio and video.Therefore,the IEEE Time-Sensitive Networking(TSN)Task Group has proposed various traffic shaping and scheduling mechanisms based on Ethernet.Among them,Asynchronous Traffic Shaping(ATS)scheduling offers higher bandwidth utilization and is easier to deploy than other schemes.However,the ATS scheduling mechanism can only be deployed in static networks and cannot support dynamic traffic joining and flexible configuration delivery.Therefore,this thesis proposes a shaping and scheduling mechanism e ATS based on software-defined network architecture,which enables dynamic traffic joining while providing deterministic delay guarantees.Firstly,this thesis describes the problem of burst traffic cascading in the existing Ethernet scheduling mechanism.Simulations are conducted to compare the delay boundary accuracy,admission control capability and bandwidth utilization of the ATS scheduling mechanism with the existing Ethernet scheduling mechanism.From the results,the performance advantages of introducing interleaving shaping in the ATS scheduling mechanism are analyzed.Secondly,to address the problem of rigid ATS configuration delivery,this thesis introduces P4 programmable technology in the data plane.The configuration of flow parameters and shaping parameters in the ATS scheduling mechanism are configured via flow tables and NETCONF protocol respectively,providing flexible flow configuration delivery while being compatible with the current configuration of shaping parameters on the Internet.Thirdly,this thesis designs and implements the components of the ATS scheduling mechanism based on the P4 software switch BMv2.The components implemented include stream filter,service data unit filter,stream gate,shaper,shaper group and transmission selection algorithm,which are divided into input modules,scheduling modules and shaping configuration modules according to their functions.Different modules work together to achieve deterministic latency guarantee while providing flexible configuration delivery capability.Finally,both functional and performance tests of the e ATS scheduling mechanism are carried out in a physical environment.In the functional tests,the components of the e ATS switch and the configuration function of the shaping parameters are tested.The results show that the functions meet expectations;In the performance tests,firstly,the performance of the flow configuration delivery is tested,which proved that the configuration information occupies a small amount of memory space and the number of configurations does not affect the forwarding rate of the switch,even in a million traffic scale network,the configuration still maintains a microsecond level of delivery delay;Secondly,the stringency of the delay boundary is tested in both single-priority and multipriority scenarios,and it is proved that the e ATS forwarding device can ensure that the queuing delay is below the theoretical delay boundary in both scenarios.