Constraint-Based Virtualization of Industrial Networks

In modern industrial solutions, Ethernet-based communication networks have been replacing bus technologies. Ethernet is no longer found only in inter-controller or manufacturing execution systems, but has penetrated into the real-time sensitive automation process (i.e., close to the machines and sensors). Ethernet itself adds many advantages to industrial environments where digitalization also means more data-driven IT services interacting with the machines. However, in order to cater to the needs of both new and more automation-related communication, a better restructuring of the network and resources among multitenant systems needs to be carried out. Various Industrial Ethernet (IE) standards already allow some localized separation of application flows with the help of Quality of Service (QoS) mechanisms. These technologies also expect some planning or engineering of the system which takes place by estimating worst-case scenarios of possible traffic generated by all assumed applications. This approach, however, lacks the flexibility to add new services or to extend the system participants on the fly without a major redesign and reconfiguration of the whole network. Network virtualization and segmentation is used to satisfy these requirements of more support for dynamic scenarios, while keeping and protecting time-critical production traffic. Network virtualization allows slicing of the real physical network connecting a set of applications and end devices into logically separated portions or Slices. A set of resource demands and constraints is defined on a Slice or Virtual Network level. Slice links are then mapped over physical paths starting from end devices through forwarding devices that can guarantee these demands and constraints. In this chapter, the modeling of virtual industrial network constraints is addressed with a focus on communication delay. For evaluation purposes, the modeled network and mapping criteria are implemented in the Virtual Network Embedding (VNE) traffic-engineering platform ALEVIN [1].