Application of Network Calculus Models on Programmable Device Behavior

Critical applications, such as industrial control systems or remote medical applications, require highly reliable networks. A key enabler of such applications are networks that deliver the required strict performance guarantees. A prominent tool for deriving such guarantees for networks and the involved components is network calculus (NC). Device specifics may have a stark influence on model characteristics, making modeling in heterogeneous environments work-intensive. OpenFlow and P4 are two approaches that emerged from the Software-Defined Networking (SDN) community making networks more flexible and, consequentially, even harder to model.In this work, we demonstrate a novel approach that uses NC to model such SDN-based devices despite their increased complexity. Abstracting away from overall device behavior, we initially model only the fundamental building blocks of SDN devices that define network device behavior. NC provides a framework to compose different NC models into a single model, which we use to combine the building blocks into a model that describes a network device program built from these building blocks. This approach allows for modeling a maximal number of devices with a minimal amount of measurements. We apply our approach to two different SDN devices, the Zodiac FX and the NetFPGA SUME. A comparison between the prediction of our composed models and real measurements reveals a prediction error below 1 %, thereby proving the validity of our approach.