I. Introduction
The fourth industrial revolution, known as Industry 4.0, brings cyber-physical systems and Internet of Things (IoT) to industrial manufacturing systems [1], [2]. Furthermore, the number of interconnected physical devices will increase drastically, and they will continuously interact with local cloud services in order to act intelligently and flexibly. This introduces numerous challenges to industrial networks, which have traditionally been very static and strongly isolated [3], [4]. First, it is expected that many new technologies, comprising both wired and wireless connections, will gradually be introduced into production lines resulting in a very heterogeneous network [5]. Second, the network will have to serve a wide range of applications with different quality-of-service (QoS) requirements, ranging from traditional closed-loop control systems to event-driven sensors and augmented reality (AR) displays. For instance, control and alarm systems may require a delivery reliability in the order of and end-to-end latencies in the range of 0.5–5 ms, while, at the same time, interactive applications require high data rates and moderate latencies [6], [7]. Finally, the increased system complexity also poses a challenge in managing the network and, in particular, the end-to-end QoS. This necessitates programmability of the network, as well as a framework for analyzing the end-to-end network characteristics [3], [8].