Reliability-Aware Flow Distribution Algorithm in SDN-Enabled Fog Computing for Smart Cities

In order to improve the performance of the communication infrastructure in smart cities, integration of two emerging technologies, namely Fog Computing (FC) and Software-Defined Networking (SDN), has been proposed and is gaining momentum. The resulting SDN-based FC integrated architecture is expected to meet the Internet-of-Things (IoT) applications' requirements, especially in terms of easy manageability, high scalability, increased reliability, and low latency. Existing traffic engineering approaches proposed for SDN-based FC for IoT compute the route between an IoT device and fog server subject to some Quality of Service (QoS) constraints. However, these approaches ignore the link reliability level in the route computation process. Unlike them, this paper proposes a Reliability-Aware Flow Distribution Algorithm (RAFDA) and two associated optimization algorithms called Reactive Reliability-Aware Heuristic Algorithms (RRAHA-1 and RRAHA-2), which distribute the flows on the links based on the links' reliability levels, subject to additional constraints like traffic load on the link, bandwidth allocation, link utilization, and end-to-end delay. The proposed algorithms minimize the impact of link failure occurrences on the ongoing time-critical flows (applications/services) of smart cities. The proposed algorithms, evaluated using both real network traces and simulations, outperform existing approaches in terms of performance for delay-sensitive services in smart cities.