Programmable Data Plane-Based TCP Multi-Queue Scheduling Scheme Using RTT and CCA Classification

Abstract

Transmission Control Protocol (TCP) congestion control plays a vital role in maintaining the quality of Internet communications. However, flows with different Round-Trip Times (RTTs) and Congestion Control Algorithms (CCAs) significantly degrade throughput fairness when sharing a bottleneck link. Especially in environments where CUBIC and BBR coexist, existing controls at intermediate nodes struggle to suppress bandwidth dominance by specific flows. This study proposes a method using the P4 programmable data plane to classify flows into independent queues based on two axes: RTT length and CCA type. Furthermore, applying Fair Queuing with Variable Holding Time (FQ-VHT) to each classified queue ensures equitable bandwidth distribution for each flow, even in environments where diverse communication characteristics coexist.