A Frame Packing Framework for Control Systems

Ethernet has become more and more popular in the industrial world. The full duplex standard and the arrival of switches have made this protocol competitive for real-time purposes. In automation systems, a lot of energy is invested to integrate technologies using Ethernet into control systems. Since Ethernet frames have an important payload, and control signals a very small size, monopolizing an Ethernet frame for a single signal is quite inefficient. A solution to reduce this overhead is to allow sending several signals into the same Ethernet frame. This problem, close to the bin packing problem, is NP-hard. With signals having end-to-end deadlines to respect and different periods and release times, this problem becomes even more complex. We propose here to design a communication framework realizing such a frame packing. The challenge is to generate near-optimal solutions in terms of bandwidth utilization while meeting the different real-time constraints related to automation control systems