TCP's dynamic responding to packet losses in wired-wireless networks

Abstract

When TCP operates in wireless networks, its congestion control algorithms such as fast retransmit/recovery (FRR) and retransmission timeouts (RTO) are often triggered regardless of congestion. Such FRRs/RTOs non-related to congestion incur TCP's misbehavior such as blindly halving the transmission rate, unnecessarily retransmitting the outstanding packets which may be in the bottleneck queue. Although many previous works have been proposed to detect the FRRs/RTOs non-related to congestion, they paid little attention on effectively adjusting the transmission rate according to network conditions. In this paper, we propose a new scheme to dynamically respond to FRRs/RTOs by considering network conditions such as the available bandwidth and the loss rate. Our scheme adjusts the transmission rate in proportion to the available bandwidth in order to quickly and fully utilize the available bandwidth, and then re-adjusts it in inverse proportion to the loss rate in order to avoid burst losses and long go-back-N re-transmissions. Throughout the extensive experiments, we show that our scheme significantly outperforms previous works while it maintains the fair and friendly behavior to other TCP connections.