The Internet of Things (IoT) allows communication between devices, things, and any digital assets that send and receive data over a network without requiring interaction with a human. The main characteristic of IoT is the enormous quantity of data created by end-user’s devices that needs to be processed in a short time in the cloud. The current cloud-computing concept is not efficient to analyze very large data in a very short time and satisfy the users’ requirements. Analyzing the enormous quantity of data by the cloud will take a lot of time, which affects the quality of service (QoS) and negatively influences the IoT applications and the overall network performance. To overcome such challenges, a new architecture called edge computing — that allows to decentralize the process of data from the cloud to the network edge has been proposed to solve the problems occurred by using the cloud computing approach. Furthermore, edge computing supports IoT applications that require a short response time and consequently enhances the consumption of energy, resource utilization, etc. Motivated by the extensive research efforts in the edge computing and IoT applications, in this paper, we present a comprehensive review of edge and fog computing research in the IoT. We investigate the role of cloud, fog, and edge computing in the IoT environment. Subsequently, we cover in detail, different IoT use cases with edge and fog computing, the task scheduling in edge computing, the merger of software-defined networks (SDN) and network function virtualization (NFV) with edge computing, security and privacy efforts. Furthermore, the Blockchain in edge computing. Finally, we identify open research challenges and highlight future research directions.

物联网 (IoT) 允许通过网络发送和接收数据的设备、事物和任何数字资产之间进行通信，而无需与人进行交互。物联网的主要特点是终端用户设备产生的海量数据需要在云端短时间内处理。当前的云计算概念不能有效地在很短的时间内分析非常大的数据并满足用户的需求。云分析海量数据需要花费大量时间，这会影响服务质量（QoS）并对物联网应用和整体网络性能产生负面影响。为了克服这些挑战，已经提出了一种称为边缘计算的新架构——允许将数据从云到网络边缘的过程分散，以解决使用云计算方法出现的问题。此外，边缘计算支持需要较短响应时间的物联网应用，从而提高能源消耗、资源利用率等。受边缘计算和物联网应用广泛研究工作的推动，在本文中，我们全面回顾了物联网中的边缘和雾计算研究。我们研究了云、雾和边缘计算在物联网环境中的作用。随后，我们详细介绍了边缘计算和雾计算的不同物联网用例，边缘计算中的任务调度，软件定义网络 (SDN) 和网络功能虚拟化 (NFV) 与边缘计算、安全和隐私工作的合并。此外，边缘计算中的区块链。最后，我们确定开放的研究挑战并强调未来的研究方向。