A Bandwidth Allocation Method of AVB Traffic Based on Link Load Balancing in TSN

As a new generation technology of Ethernet, time sensitive networking (TSN) plays an increasingly important role in industrial control, vehicle network and other fields, as it guarantees low-delay and low-jitter transmission of time sensitive traffic. As one of the key shaping technologies of TSN, credit-based shaping (CBS) guarantees the deterministic transmission of audio video bridging (AVB) traffic by reserving bandwidth. The existing bandwidth allocation methods based on network calculus mostly do not consider the impact of routing on the schedulability of AVB traffic, and the bandwidth allocation results are poor and the solution time is long when the network is in a large scale. Therefore, this paper proposed a bandwidth allocation method based on link load balancing. Firstly, the link load balancing routing algorithm was used to calculate the optimal path for each AVB traffic. Then, based on the flow path and network calculus, the arrival and service curves of each switch’s outbound port traffic were analyzed to obtain the worst-case forwarding delay. Finally, the optimization objectives and constraints for bandwidth allocation were established, a heuristic algorithm was used to solve bandwidth allocation, and the bandwidth parameter configuration was optimized during the solving process. The experimental results show that the AVB traffic bandwidth allocation method based on link load balancing can improve the schedulability of AVB traffic by 15 to 45 percentage points, compared with existing bandwidth allocation methods. Optimizing parameter configuration can increase the bandwidth solving speed by more than twice and obtain better bandwidth allocation results, which can effectively cope with large-scale dynamic changes in TSN networks.