Using ECN Marks to Improve TCP Performance over Lossy Links

TCP was designed for wireline networks, where loss events are mostly caused by network congestion. The congestion control mechanism of current TCP uses loss events as the indicator of congestion, and reduces its congestion window size. However, when a lossy link is involved in a TCP connection, non-congestion random losses should also be considered. The congestion window size should not be decreased if a loss event is caused by link corruptions. To improve TCP performance over lossy links, in this paper, we first present that zero congestion loss could be achieved by appropriately setting the ECN marking threshold in the RED buffer. Secondly, we propose a new TCP algorithm, called Differentiation Capable TCP (Diff-C-TCP). Diff-C-TCP makes an assumption that packet losses are caused by link corruptions, and uses ECN (Explicit Congestion Notification) to determine any loss that may occasionally happen due to network congestion. We have shown that Diff-C-TCP performs very well in the presence of a lossy link.