The power of explicit congestion notification

摘要: Despite the fact that Explicit Congestion Notification (ECN) demonstrated a clear potential to substantially improve network performance, recent measurements reveal an extremely poor usage of this option in today's Internet. In paper, we analyze roots phenomenon and develop set novel incentives encourage providers, end-hosts, web servers apply ECN.Initially, examine fundamental drawback current ECN specification, demonstrate absence indications TCP control packets can dramatically hinder system performance. While security reasons primarily prevent bits SYN packets, show applying ACK significantly performance without introducing any or stability side-effects. Our experiments on cluster dramatic improvement over existing specification: throughput increases by more than 40%, while average response-time simultaneously decreases nearly order magnitude.In light above finding, using large-scale simulations, modeling, experiments, re-investigate relevance ECN, provide practical recommendations insights: (i) systematically improves all investigated AQM schemes; contrary common belief, particularly holds for RED. (ii) The impact is highest web-only traffic mixes such even generic algorithm with support outperforms non-ECN-enabled schemes investigated. (iii) Primarily due moderate queuing levels, superiority other mechanisms largely high-speed backbone routers, general scenarios. (iv) End-hosts exercise benefits instantly, waiting entire Internet community option.