The growth of Internet of Things (IoT) devices with multiple radio interfaces has resulted in a number of urban-scale deployments of IoT multinetworks, where heterogeneous wireless communication solutions coexist (e.g., WiFi, Bluetooth, Cellular). Managing the multinetworks for seamless IoT access and handover, especially in mobile environments, is a key challenge. Software-defined networking (SDN) is emerging as a promising paradigm for quick and easy configuration of network devices, but its application in urban-scale multinetworks requiring heterogeneous and frequent IoT access is not well studied. In this paper we present UbiFlow, the first software-defined IoT system for combined ubiquitous flow control and mobility management in urban heterogeneous networks. UbiFlow adopts multiple controllers to divide urban-scale SDN into different geographic partitions (assigning one controller per partition) and achieve distributed control of IoT flows. A distributed hashing based overlay structure is proposed to maintain network scalability and consistency. Based on this UbiFlow overlay structure, the relevant issues pertaining to mobility management such as scalable control, fault tolerance, and load balancing have been carefully examined and studied. The UbiFlow controller differentiates flow scheduling based on per-device requirements and whole-partition capabilities. Therefore, it can present a network status view and optimized selection of access points in multinetworks to satisfy IoT flow requests, while guaranteeing network performance for each partition. Simulation and realistic testbed experiments confirm that UbiFlow can successfully achieve scalable mobility management and robust flow scheduling in IoT multinetworks; e.g., 67.21 percent throughput improvement, 72.99 percent reduced delay, and 69.59 percent jitter improvements, compared with alternative SDN systems.

中文翻译：

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迈向分布式 SDN：软件定义城市物联网中的移动性管理和流量调度

具有多个无线电接口的物联网 (IoT) 设备的增长导致了许多城市规模的物联网多网络部署，其中异构无线通信解决方案共存（例如，WiFi、蓝牙、蜂窝）。管理多网络以实现无缝物联网访问和切换，尤其是在移动环境中，是一项关键挑战。软件定义网络 (SDN) 正在成为快速轻松配置网络设备的有前途的范例，但其在需要异构和频繁物联网访问的城市规模多网络中的应用尚未得到很好的研究。在本文中，我们介绍了 UbiFlow，这是第一个软件定义的物联网系统，用于在城市异构网络中结合无处不在的流量控制和移动性管理。UbiFlow采用多控制器将城市规模的SDN划分为不同的地理分区（每个分区分配一个控制器），实现物联网流量的分布式控制。提出了一种基于分布式散列的覆盖结构来保持网络可扩展性和一致性。基于这种 UbiFlow 覆盖结构，对可扩展控制、容错和负载平衡等与移动性管理相关的问题进行了仔细检查和研究。UbiFlow 控制器根据每个设备的要求和整个分区的能力来区分流调度。因此，它可以在多网络中呈现网络状态视图和优化选择接入点以满足物联网流量请求，同时保证每个分区的网络性能。仿真和真实的测试台实验证实，UbiFlow 可以在物联网多网络中成功实现可扩展的移动管理和稳健的流量调度；例如，与替代 SDN 系统相比，吞吐量提高了 67.21%，延迟降低了 72.99%，抖动降低了 69.59%。