MVNOCoreSim: A Digital Twin for Virtualized IoT-Centric Mobile Core Networks.

The rapid growth of connected devices has led to the implementation of Internet of Things (IoT)-centric platforms designed to provide connectivity for machine-to-machine-type communication. Specifically, mobile virtual network operators (MVNOs) provide global service for IoT use cases by leveraging roaming in readily deployed physical networks. This global deployment of connected devices poses a significant challenge regarding the operation of centralized core networks with respect to dimensioning, scaling, as well as system survivability in case of signaling incidents. Overload control mechanisms for IoT mobile networks offer a proactive solution for mitigating excessive signaling traffic from IoT devices in mobile core networks. However, global scaling and a heterogeneous composition of devices present network operators with additional challenges. To address these challenges, this work presents a detailed, protocol-level simulation framework of a real-world IoT MVNO core network. We present both models for the expected IoT signaling load and the processing of signaling messages based on measurements in a live, production environment as well as a dedicated testbed. Finally, we present a case study on various overload mechanisms and identify critical performance characteristics to compare their performance. The results of this study categorize overload control mechanisms and shed light on the necessity for MVNOs to deal with the upcoming IoT traffic by defining appropriate overload control mechanisms in mobile core networks to ensure network survivability under unforeseen conditions.