Topology Design of Time Sensitive Networks in A Smart Factory

The Time Sensitive Network (TSN), currently being standardized by the IEEE 802.1 working group, has been getting much attention for transporting time-triggered (TT) data flows in a smart manufacturing factory. In a TSN, several mechanisms (synchronization, frame scheduling, gate control, etc.) are available to guarantee deterministic and very low delay for periodical TT flows. Previous studies on guaranteeing deterministic low delay for TT flows focus on modeling the scheduling constraints. However, without considering routing issue and network topology design, a TSN’s capacity may be limited due to link congestion. We believe that a good TSN design, in particular for supporting TT flows, should include the following three parts: topology design, routing decision, and scheduling. This paper establishes an optimization model for designing a hierarchical interconnecting-tree network topology, taking flow demand, switch bandwidth, and geography factor into consideration. It is capable of constructing a minimized-cost TSN in a smart factory while also allowing for enhanced network resilience at the expense of extra cost.