Co-design Approach of Scheduling and Routing in Time Sensitive Networking

Abstract

Time Sensitive Networking (TSN) is the future technology of industrial deterministic real-time communication. IEEE 802.1Qbv is one of the critical standards, which defines a gating mechanism, i.e. the time-aware shaper. This mechanism employs the time transmission gate and gate control list (GCL) to guarantee the real-time transmission for time-critical streams. However, most existing works focus on the single-level 802.1Qbv scheduling problems without consideration of route planning or queue assignment. In this paper, the deterministic transmission problem of multiple time-critical streams over the TSN-capable multi-hop and multi-queue network is investigated. To guarantee deterministic end-to-end delay for multiple time-critical streams, a co-design constraint set of scheduling and routing is constructed. Integrated with the constraints, a mapping method via Satisfiability Modulo Theories (SMT) and an optimal co-design approach via Optimization Modulo Theories (OMT) are proposed. The objective of the proposed approach is to maximize network utilization by minimizing the usage of switch nodes for time-critical streams while guaranteeing the schedulability of network systems. Compared with the previous scheduling methods, the simulations show that the network utilization and the schedulability of network systems are significantly improved by the proposed approach.