Recent advances in the context of Internet of Things (IoT) have led to the emergence of many useful IoT applications with different Quality of Service (QoS) requirements. The fog-cloud computing systems offer a promising environment to provision resources for IoT application services. However, providing an efficient solution to service placement problem in such systems is a critical challenge. To address this challenge, in this paper, we propose a QoS-aware service placement policy for fog-cloud computing systems that places the most delay-sensitive application services as closer to the clients as possible. We validate our proposed algorithm in the iFogSim simulator. Results demonstrate that our algorithm achieves significant improvement in terms of service latency and execution cost compared to simulators built-in policies.
