Design, Discussion, and Its Potential Performance Evaluation of In-Network Congestion Control

As the Internet becomes larger-scaled and more diversified, the traditional end-to-end (E2E) congestion control faces various problems such as low throughput on long-delay networks and unfairness among flows with different network situations. In this paper, we propose a novel congestion control architecture, called in-network congestion control (NCC). Specifically, by introducing one or more nodes (NCC nodes) on an E2E network path, we divide the network path into multiple sub-paths and maintain a congestion-control feedback loop on each sub-path. In each sub-path, a specialized congestion control algorithm can be applied according to its network characteristics. This architecture can provide various advantages compared with the traditional E2E congestion control, such as higher data transmission throughput, better per-flow fairness, and incremental deployment nature. In this paper, we describe NCC's advantages and challenges, and clarify its potential performance by evaluation results. We reveal that the E2E throughput improves by as much as 159% by just introducing NCC nodes. Furthermore, increasing the number of NCC nodes improves the E2E throughput and fairness among flows by up to 258% and 151%, respectively.