报告题目： Early Flow Discard for packet scheduling

报告人：陈金榜博士

主持人：张卫教授

时间：2012年12月28日（星期五）上午9：00

地点：629会议室 

报告摘要

As the Internet evolves over the years, a large number of applications emerge, ranging from HTTP, FTP to P2P, and more recently multimedia streaming, on-line game and social networks, with varying service requirements in terms of bandwidth, delay, loss rate and so on. Still, the Internet traffic exhibits a high variability property – the majority of the flows are of small sizes while a small percentage of very long flows contribute to a large portion of the traffic volume. Several studies reveal that small flows are in general related to interactive applications – such examples consist of Web browsing, mail checking, DNS queries, and more recently tweets, posts, chats, etc. – for which one expects to obtain good user perceived performance, most often in terms of short response time. However, the classical FIFO/drop-tail scheme deployed in today’s routers/switches is well known to bias against short flows over long ones.

To tackle this issue over a best-effort network, a great deal of size-based scheduling solutions have been proposed in the last decade. The key idea is to favor short flows at the expense of long ones. Although appealing by offering small response time to short flows, most of them feature one or more significant drawbacks/limits: starvation to long flows, scheduling decision based on a single dimension, namely flow size, global modification of end hosts, and the overhead of flow state maintenance. In this work, we have proposed a novel and simple scheduling algorithm named EFD (Early Flow Discard), which is able to overcome all the drawbacks aforementioned. We first evaluate the performance of EFD in a single-bottleneck wired network through extensive simulations. We then discuss the possible variants of EFD and EFD’s adaptations to 802.11 WLANs – mainly refer to EFDACK and PEFD, which keep track of the volumes exchanged in both directions or simply count packets in a single direction, aiming at improving the flow level fairness and interactivity in WLANs.

报告人简介：陈金榜，2006年7月获西安交通大学信息与通信工程专业学士学位，后赴意大利和法国深造，分别于2008年11月和2012年9月获意大利都灵理工大学（Politecnico di Torino）计算机与通信网络专业硕士学位及法国国立巴黎高等电信（Telecom ParisTech）计算机科学与技术（计算机网络）博士学位，2009-2012年在Eurecom（http://www.eurecom.fr/）从事博士研究。主要研究方向：Size-based Scheduling in wired and wireless networks, Traffic Measurement等。