Cloud computing, despite its inherent advantages (e.g., resource efficiency) still faces several challenges. the wide are network used to connect the cloud to end-users could cause high latency, which may not be tolerable for some applications, especially Internet of Things (IoT applications. Fog computing can reduce this latency by extending the traditional cloud architecture to the edge of the network and by enabling the deployment of some application components on fog nodes. Application providers use Platform-as-a-Service (PaaS) to provision (i.e., develop, deploy, manage, and orchestrate) applications in cloud. However, existing PaaS solutions (including IoT PaaS) usually focus on cloud and do not enable provisioning of applications with components spanning cloud and fog. provisioning such applications require novel functions, such as application graph generation, that are absent from existing PaaS. Furthermore, several functions offered by existing PaaS (e.g., publication/discovery) need to be significantly extended in order to fit in a hybrid cloud/fog environment. In this paper, we propose a novel architecture for PaaS for hybrid cloud/fog system. It is IoT use case-driven, and its applications' components are implemented as Virtual Network Functions (VNFs) with execution sequences modeled s graphs with sub-structures such as selection and loops. It automates the provisioning of applications with components spanning cloud and fog. In addition, it enables the discovery of existing cloud and fog nodes and generates application graphs. A proof of concept is built based on Cloudify open source. Feasibility is demonstrated by evaluating its performance when PaaS modules and application components are placed in clouds and fogs in different geographical locations.

中文翻译：

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基于 NFV 的物联网平台即服务——混合云/雾系统

云计算尽管具有固有的优势（例如资源效率），但仍面临一些挑战。用于将云连接到最终用户的广泛网络可能会导致高延迟，这对于某些应用程序来说可能是无法容忍的，尤其是物联网（IoT 应用程序。雾计算可以通过将传统云架构扩展到边缘来减少这种延迟网络，并通过在雾节点上部署一些应用程序组件。应用程序提供商使用平台即服务 (PaaS) 在云中提供（即开发、部署、管理和编排）应用程序。但是，现有的PaaS 解决方案（包括物联网 PaaS）通常专注于云，并且不会启用跨云和雾组件的应用程序供应。供应此类应用程序需要新颖的功能，例如，现有 PaaS 中不存在的应用程序图生成。此外，现有 PaaS 提供的若干功能（例如，发布/发现）需要显着扩展，以适应混合云/雾环境。在本文中，我们为混合云/雾系统的 PaaS 提出了一种新颖的架构。它是物联网用例驱动的，其应用程序的组件作为虚拟网络功能 (VNF) 实现，执行序列建模为具有子结构（例如选择和循环）的图。它使用跨越云和雾的组件自动配置应用程序。此外，它还可以发现现有的云和雾节点并生成应用程序图。概念证明是基于 Cloudify 开源构建的。