The Constrained Application Protocol (CoAP) is gaining attention as a standardised RESTful interface for the Internet of Things (IoT). Recent studies have focused on different congestion control strategies for CoAP, in order to ensure proper operation of large-scale IoT deployments. In this paper, we carry out a performance evaluation of different congestion control policies for CoAP in a realistic environment by exploiting WiSHFUL, a platform for large-scale experimentation of network architectures. Our goal is to analyse different congestion control policies and their interplay with the routing protocol in a real environment, where unstable links and route fluctuations are frequent, due to channel variability. The results of our experiments highlight that the dynamics of the routing protocol have a noticeable impact and can impair significantly the performance of the congestion control algorithm. Specifically, the influence of the routing protocol depends on the specific congestion control policy adopted: an aggressive policy that re-transmits messages more frequently, e.g. CoCoA, is more penalised than others, in terms of throughput.

约束应用协议（CoAP）作为物联网（IoT）的标准RESTful接口而受到关注。最近的研究集中在针对CoAP的不同拥塞控制策略上，以确保大规模IoT部署的正常运行。在本文中，我们通过利用WiSHFUL（网络体系结构的大规模实验平台）对现实环境中CoAP的不同拥塞控制策略进行了性能评估。我们的目标是在实际环境中分析不同的拥塞控制策略及其与路由协议的相互影响，在实际环境中，不稳定的链接和路由波动由于信道可变性而经常发生。我们的实验结果表明，路由协议的动态性具有明显的影响，并且可能严重削弱拥塞控制算法的性能。具体而言，路由协议的影响取决于所采用的特定拥塞控制策略：在吞吐量方面，比其他策略更频繁地重发消息（例如CoCoA）的积极策略会受到不利影响。