学术报告

报告题目：One more bit is enough

副 标 题：With a brief review on the Internet congestion control research over the last two decades

报 告 人：Yong Xia, Ph.D.

报告时间：2005年9月23日（星期五）下午4：00--5：30

报告地点：信息技术大楼（FIT）1区315

Abstract: Achieving efficient and fair bandwidth allocation while minimizing packet loss in high bandwidth-delay product networks has long been a daunting challenge. Existing end-to-end congestion control (e.g.,TCP) and traditional congestion notification schemes (e.g.,TCP+AQM/ECN) have significant limitations in achieving this goal.While the recently proposed XCP protocol addresses this challenge, XCP requires multiple bits to encode the congestion-related information exchanged between routers and end-hosts. Unfortunately, there is no space in the IP header for these bits, and solving this problem involves a non-trivial and time-consuming standardization process. In this paper, we design and implement a simple, low-complexity protocol, called Variable-structure congestion Control Protocol (VCP), that leverages only the existing two ECN bits for network congestion feedback, and yet achieves comparable performance to XCP, i.e., high utilization, low persistent queue length, negligible packet loss rate, and reasonable fairness. On the downside, VCP converges significantly slower to a fair allocation than XCP. We evaluate the performance of VCP using extensive ns2 simulations over a wide range of network scenarios. To gain insight into the behavior of VCP, we analyze a simple fluid model, and prove a global stability result for the case of a single bottleneck link shared by flows with identical round-trip times.

Bio: Yong graduated with a Bachelors degree from Huazhong University of Science and Technology, a Masters degree from the Institute of Automation, Chinese Academy of Sciences, and a Ph.D. degree from Rensselaer Polytechnic Institute (RPI). In summer 2003, he did visiting research at U.C.Berkeley. He is part of a Microsoft team that designed an instant audio/video communication platform currently serving millions of users. His research interests are computer networking, multimedia communication, distributed systems and ubiquitous computing.

联系人：康毅

电 话： 62795788

E-mail: xxxy@mail.tsinghua.edu.cn