Achieving high throughput and low delay by accurately regulating link queue length over mobile data network

Knowledge of the queue length of the bottleneck link has many potential applications such as congestion control, traffic engineering, traffic policing, content adaptation, QoS monitoring and provisioning, etc. A recent work proposed a new Sum-of-Delay with Timestamp (SoD-TS) algorithm which can accurately estimate queue length in mobile networks with both bandwidth variations and uplink delay variations by exploiting the existing TCP Timestamp option. By making use of SoD-TS we developed a novel transport protocol - queue-length-aware TCP (TCP-QLA), that tackles the problem of bufferbloat to provide better QoS for applications requiring low end-to-end delay and/or high bandwidth utilization. Trace-driven simulation shows that compared to TCP CUBIC TCP QLA can reduce the RTT by a factor of 2.7 while still achieving over 97% bandwidth utilization. Moreover, TCP-QLA further reduces RTT by 50% compared to delay-based TCP such as FAST TCP and TCP Vegas.