Improving TCP performance over mobile data networks with opportunistic retransmission
Ke Liu, Jack Y. B. Lee · 2013
Recent advances in high-speed mobile networks have revealed new bottlenecks in the ubiquitous TCP protocol deployed in the Internet. In addition to differentiating random loss from congestion loss, our experiments revealed that TCP's flow control mechanism can become a significant bottleneck during TCP's loss recovery phase, resulting in bandwidth efficiency as low as 0.05. To tackle this problem we develop a novel opportunistic retransmission algorithm to enable the TCP sender to transmit new packets even before the loss recovery phase is completed, resulting in significant improvement in TCP's bandwidth efficiency. We applied the proposed mechanism to three TCP variants and developed system models to analyze their performance. Experimental results showed that TCP's throughput can be improved by up to 56% in real-world settings.