Application-aware industrial ethernet based on an SDN-supported TDMA approach

Abstract

In industrial automation environments, networks providing a reliable and timely data delivery are required. Fulfilling this need, Industrial Ethernet (IE) systems have established as an important networking technology in many application areas. Although there are several IE solutions on the market, all of these systems have notable drawbacks, like limited scalability or the introduction of a Single Point of Failure (SPoF).Therefore, we propose a novel IE system that is based on Software Defined Networking (SDN). Originally meant for data center and IT networks, the SDN concept offers features like central network management functions and a fine-grained traffic control that allows to support many applications with diverse requirements even in the same network. Thereby, SDN is also perfectly suited for complex automation environments. To guarantee RT data transmission as well as scalability and an efficient resource usage, our IE system uses a Medium Access Control (MAC) scheme that is based on a Time Division Multiple Access (TDMA) mechanism that is extended by simultaneous data transmissions on physically separate links. The enhanced TDMA mechanism is configured by a joint routing and scheduling algorithm that takes application requirements into account. Our theoretical analysis as well as results achieved with a prototype implementation of the system confirm the applicability of our concept in demanding automation environments with applications that require a worst case communication latency below 1 ms.

Software Defined Networks in Industrial Automation

“…In 2015, we first proposed the integration of SDN in industrial automation by reforming the current industry communication pyramid to become a single Ethernet-based solution in a conceptual paper [14]. In [18], the authors proposed an application-aware industrial Ethernet by exploiting the capabilities of SDN in collecting topology information and application requirements. A newly developed routing and scheduling algorithm uses the received information to generate network configuration autonomously.…”

Dynamic Flow Migration for Delay Constrained Traffic in Software-Defined Networks

“…Owing to the advantages of the centralized control logic, SDN has recently been proposed as a means of enabling hardreal time communication for industrial control applications [3], [4]. The proposed solutions either use SDN for assigning time slots to flows across the network [4], or for enforcing flowspecific bandwidth allocations combined with static priority queuing in the switches [3].…”

“…The proposed solutions either use SDN for assigning time slots to flows across the network [4], or for enforcing flowspecific bandwidth allocations combined with static priority queuing in the switches [3]. While these works show the feasibility of using SDN for hard real-time communication, they have in common that they do not support changing networks, thus they do not allow adding new devices and flows into the network at runtime, without potentially interrupting existing flows.…”

“…Graph constructed for the network in Figure 1. 4 Find shortest path from to any * ∈ ℛ * in graph ; and any route ′ ∈ ℛ * , and returns it as the FM sequence . Otherwise, it returns the empty sequence.…”

“…Therefore, previous works have developed new RT communication systems that overcome the drawbacks of the existing IE systems while providing comparable latency characteristics (below 1 ms) and independence of the used network topology [3], [4]. These works leverage the approach of SoftwareDefined Networking (SDN) and exploit the SDN controller's central view on the network to discover the topology and to collect the requirements of the applications using the network.…”