Session-aware congestion control for TCP Incast in datacenter networks

TCP Incast is one of the typical datacenter problems that may affect network efficiency in a many to one transmission session, in which the completion time of the whole session depends on the last finishing flow. In this paper a session-aware mechanism is proposed that intelligently chooses only the leading flows to slow down at the presence of congestion, so the lagging ones will have a higher chance to catch up to achieve better session completion time and goodput. Compared to existing solutions, the proposed one introduces no change to the TCP protocol and no extra messaging for the internal status of either TCP or the intermediate switches. Experimental results show that the proposed mechanism can indeed balance the progress among Incast flows and achieve a shorter session time and higher goodput.