Lecture

Thomas Karagiannis
University of California, Riverside
Department of Computer Science & Engineering

Date: 27 February 2006
Seminar Room1 - FORTH

Host: Maria Papadopouli, Telecommunications and Network Lab

LECTURE 1
Time: 12:00-13:00

Network Measurements in the Dark: Characterizing the Unknown

Abstract:

As the prevalence of novel applications (peer-to-peer, real-time media, VoIP, etc.) and the manifestation of growing malicious activity transform the nature of the Internet traffic, collection and interpretation of empirical Internet data remains a critical yet challenging task. While measurement provides the only accurate source of information regarding the usage of the network resources, the community no longer enjoys the fleeting benefit of traditional network traffic, which was relatively easily profiled due to the existence of limited applications with well-defined structure.

My work addresses the challenge of profiling the "unknown" by focusing on robust network measurements and characterization of network traffic in the face of a constantly changing traffic mix. In this talk, I will introduce a novel perspective into the analysis of Internet traffic based on two key elements: a) shifting the focus from modeling the statistics of the individual network flows to studying the behavior of the Internet host, and b) understanding the intrinsic properties of application connection patterns. I will further describe how such an approach can be successfully applied to the identification of peer-to-peer traffic and in general to the characterization of the majority of popular applications in today's Internet. Finally, I will briefly discuss the implications of my work on different aspects of the network (e.g., content distribution), and how this concept of traffic modeling stimulates interesting new directions for future research in various areas, such as security and network management and configuration.

 

LECTURE 2
Time: 16:00-17:00

Should Internet Service Providers Fear Peer-Assisted Content
Distribution

Abstract:

Recently, peer-to-peer (P2P) networks have emerged as an attractive solution to enable large-scale content distribution without requiring major infrastructure investments. While such P2P solutions appear highly beneficial for content providers and end-users, there seems to be a growing concern among Internet Service Providers (ISPs) that now need to support the distribution cost. In this work, we explore the potential impact of future P2P file delivery mechanisms as seen from three different perspectives: i) the content provider, ii) the ISPs, and iii) individual content consumers. Using a diverse set of measurements including BitTorrent tracker logs and payload packet traces collected at the edge of a 20,000 user access network, we quantify the impact of peer-assisted file delivery on end-user experience and resource consumption. We further compare it with the performance expected from traditional distribution mechanisms based on large server farms and Content Distribution Networks (CDNs).

While existing P2P content distribution solutions may provide significant benefits for content providers and end-consumers in terms of cost and performance, our results demonstrate that they have an adverse impact on ISPs' costs by shifting the associated capacity requirements from the content providers and CDNs to the ISPs themselves. Further, we highlight how simple "locality-aware" P2P delivery solutions can significantly alleviate the induced cost at the ISPs, while providing an overall performance that approximates that of a perfect world-wide caching infrastructure.

Bio:

Detailed CV available at
http://www.cs.ucr.edu/~tkarag/papers/resume.pdf