111 Managing the data generated by Internet of Things (IoT) sensors is one of the biggest challenges 112 faced when deploying an IoT system. Traditional cloud-based IoT systems are challenged by the 113 large scale, heterogeneity, and high latency witnessed in some cloud ecosystems. One solution is 114 to decentralize applications, management, and data analytics into the network itself using a 115 distributed and federated compute model. This approach has become known as fog 116 computing. This document presents a formal definition of fog and mist computing and how they 117 relate to cloud-based computing models for IoT. This document further characterizes important 118 properties and aspects of fog computing, including service models, deployment strategies, and 119 provides a baseline of what fog computing is, and how it may be used. 120 121