Network Coordinates Research at Tsinghua University

• Network coordinates (NC) system is an efficient mechanism for Internet latency prediction with scalable measurements. Our goal is to make a practical, secure and useful NC system.
• Two of our early works focus on improving the performance of the representative NC system - Vivaldi. One is Pharos, which uses a two layer hierarchy to improve the prediction accuracy from Vivaldi. The other one is Myth, which is a scalable manner to reduce the accuracy decrease of Vivaldi under node churn.
• Most of the NC work use Euclidean distance for latency prediction. However, the prediction accuracy is largely hurt by Triangle Inequality Violation (TIV). Besides this widely used Euclidean model, we explore the potential of matrix factorization model in depth and propose a more accurate NC system called Phoenix. Phoenix remove the constraints of TIV as well as reducing the error propagation, thus it can achieve much better prediction accuracy than existing NC systems using a decentralized way.
• Since large-scale distributed NC systems have serious security issues which can greatly effect the accuracy of NC Systems, we focus our attention on designing a powerful security policy for NC Systems as well as implementing it into actual network to secure various applications based on NC Systems. Unlike other proposed security policy using reputation mechanism or vote approach, we are designing a distributed security policy based on social relationship to successfully protect NC System from typical attacks.
• We are developing some NC related applications (such as application layer anycast, scalable network monitoring system, etc) and deploying them on CERNET/CERNET2. We are also releasing an accurate, lightweight and robust NC implementation and attracting more people to use it.

• Prof. Xing Li (Advisor, deputy director of CERNET, head of NGN Lab)
• Prof. Beixing Deng (Advisor, deputy-director of Network and Human-Machine Speech Communication Research Institute)
• Dr. Yang Chen (former Principal Investigator, now Research Associate at Georg-August-University of Goettingen, Germany, while partially affiliated with NGN Lab as adjunct research scientist)
• Guodong Wang (Principal Investigator, master student at NGN Lab)
• Qiuchen Zheng (master student at NGN Lab)
• Chengbo Dong (bachelor student at NGN Lab)
• Yao Li (bachelor student at NGN Lab)
• Peng Sun (bachelor student at NGN Lab)
• Gang Wang (bachelor student at NGN Lab)
• Shining Wu (bachelor student at NGN Lab)
• Yibo Zhu (bachelor student at NGN Lab)
• Prof. Eng Keong Lua (our collaborator at College of Engineering, Information Networking Institute and Carnegie Mellon CyLab, Carnegie Mellon University, Pittsburgh, USA)
• Ang Li (our collaborator at Department of Computer Science, Duke University, USA)
• Yuankai Ge (our collaborator at Department of Electrical Engineering, Stanford University, USA)
• Genyi Zhao (alumni, now PhD student at Department of Electrical Engineering, Stanford University, USA)
• Zengbin Zhang (alumni, now PhD student at Department of Computer Science, U.C. Santa Barbara, USA)
• Xiaohan Zhao (alumni, now PhD student at Department of Computer Science, U.C. Santa Barbara, USA)
• Xiao Wang (alumni, now PhD student at University of Washington, USA)
• Xiaoxiao Song (alumni, now PhD student at Yale University, USA)

• NC Research at Harvard
• Stable and Secure Network Coordinates (Rice University)
• Pyxida: An Open Source Network Coordinate Library and Application
• Global Network Positioning (Rice University)

• This work is supported by the National Basic Research Program of China (No.2007CB310806) and the National Science Foundation of China (No.60473087, No.60703052, No.60850003).