Modern networks exhibit a high degree of variability in link rates. Cellular network bandwidth inherently varies with receiver motion and orientation, while class-based packet scheduling in datacenter and service provider networks induces high variability in available capacity for network tenants. Recent work has proposed numerous congestion control protocols to cope with this variability, offering different tradeoffs between link utilization and queuing delay. In this paper, we develop a formal model of congestion control over time-varying links, and we use this model to derive a bound on the performance of any congestion control protocol running over a time-varying link with a given distribution of rate variation. Using the insights from this analysis, we derive an optimal control law that offers a smooth tradeoff between link utilization and queuing delay. We compare the performance of this control law to several existing control algorithms on cellular link traces to show that there is significant room for optimization.

翻译：现代网络在连接率方面表现出高度的变异性。 细胞网络带宽因接收器运动和定向而具有内在差异,而数据中心和服务供应商网络中基于阶级的包包列表则导致网络承租人现有容量的高度变异性。 最近的工作提出了许多交通拥堵控制规程,以应对这种变异性,在连接利用率和排队延迟之间提供了不同的权衡取舍。在本文中,我们开发了对时间变化连接的拥堵控制正式模式,我们用这个模式来对在时间变换的连接中运行的任何交通拥堵控制规程的性能进行约束。 我们利用这一分析的洞见,得出了最佳控制法,在连接利用率和排队延迟之间实现平稳的平衡。我们将这一控制法的执行情况与一些现有的手机连接轨迹控制算法进行比较,以显示有相当大的优化空间。