If compared with Cloud computing, Fog computing is proving to support challenging scenarios imposing strict delay requirements, e.g., tactile Internet and Industrial Internet of Things (IIoT), and increased flexibility, e.g., dynamic Smart City and users’ follow-me provisioning case. In fact, by exploiting computing, storage, and connectivity resources in the proximity of sensors and actuators (for IIoT) and of mobile nodes carried by citizens (for Smart Cities), significant portions of services and functionalities can be migrated outside datacenters. However, such scenarios are characterized by increased heterogeneity of nodes in terms of hardware/software, of time-varying applications possibly offered by multiple service providers at the same time, and frequent joining/leaving of nodes as a typical behavior. To overcome these issues, the paper originally proposes Multi-Layer Advanced Networking Environment (Multi-LANE), a Multi Layer Routing (MLR) solution based on Software Defined Networking (SDN) that specifically targets the emerging and promising Fog-based deployment environments. Multi-LANE dynamically selects and exploits (even at the same time) different routing strategies and mechanisms suitable for applications with heterogeneous features and requirements. Based on its centralized point of view, our Multi-LANE SDN controller determines the most suitable path and configures the proper MLR forwarding mechanism, ranging from traditional IP and sequence-based overlays to more articulated ones based on the inspection of payload content types and values. In addition to design/implementation insights and to the availability of the Multi-LANE prototype, this paper also provides the community with a significant contribution in terms of novel models for forwarding mechanisms specialized for Fog computing scenarios.

中文翻译：

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雾环境中基于 SDN 的多层路由的参考模型和原型实现

如果与云计算相比，雾计算被证明可以支持具有严格延迟要求的具有挑战性的场景，例如触觉互联网和工业物联网 (IIoT)，以及更高的灵活性，例如动态智慧城市和用户跟随我的配置案例。事实上，通过利用传感器和执行器（对于 IIoT）以及公民携带的移动节点（对于智慧城市）附近的计算、存储和连接资源，可以将大部分服务和功能迁移到数据中心之外。然而，这些场景的特点是节点在硬件/软件方面的异构性增加，多个服务提供商可能同时提供时变应用程序，以及节点频繁加入/离开作为典型行为。为了克服这些问题，该论文最初提出了多层高级网络环境 (Multi-LANE)，这是一种基于软件定义网络 (SDN) 的多层路由 (MLR) 解决方案，专门针对新兴且有前景的基于雾的部署环境。Multi-LANE 动态选择和利用（甚至同时）适合具有异构特性和要求的应用程序的不同路由策略和机制。基于其集中的观点，我们的 Multi-LANE SDN 控制器确定最合适的路径并配置适当的 MLR 转发机制，范围从传统的 IP 和基于序列的覆盖到基于有效载荷内容类型和值检查的更清晰的覆盖. 除了设计/实施见解和 Multi-LANE 原型的可用性之外，