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TSN-VM: A Real-time and Distributed Algorithm for Scheduling-Violation Mitigation in Time-Sensitive Networking
  • Boyang Zhou ,
  • Liang Cheng
Boyang Zhou
Lehigh University

Corresponding Author:[email protected]

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Liang Cheng
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Abstract

Time-Sensitive Networking (TSN) is designed to provide deterministic performance for real-time systems, which usually have hard delay requirements for Time-Triggered (TT) traffic. In order to guarantee deterministic delays, TSN scheduling assigns specific time slots to TT frames for their transmissions by TSN switches on their paths. However, several factors may lead to scheduling violations, meaning that TT frames are not sent as scheduled. Scheduling violations can cause the increment of delays experienced by TT frames, which may breach their delay requirements.
Existing TSN scheduling methods cannot deal with scheduling violations. In our research, we propose TSN-Violation Mitigation (TSN-VM), which dynamically reconfigures the schedule at each TSN switch distributedly on a periodic basis, to mitigate the occurrence of scheduling violations. TSN-VM is built upon our new real-time detection mechanism to discover local violation information in each port of TSN switches. TSN-VM is the first real-time algorithm that can deal with scheduling violations in TSN. Its convergence conditions are demonstrated in the paper. Using TSN-VM, we can reduce the number of lag violations by more than 90.74$\%$ and decrease the average and median delays by more than 95.57$\%$ in the simulated avionic system and industrial Ethernet compared with systems without TSN-VM.