Table of Contents
University of California, Irvine
Video on Demand Streaming with Jumps
A key challenge faced by peer-to-peer (P2P) video-on-demand (VoD) systems is their ability, or lack thereof, to provide DVD-like functionality, such as pause, forward and backward seeking (or jumps). Such operations can significantly degrade the performance of a P2P system as arbitrary video segments may need to be served timely on demand. Currently, little is known of the impact that these operations can have on the swarm efficiency, user experience and server load. In this paper, we design and implement a novel P2P system called Kangaroo, which supports DVD-like jumps. Using a carefully designed peer topology management, hybrid block scheduling algorithms, and a smart tracker, Kangaroo provides low buffering times and high swarming throughput under jump operations, without the need for overly provisioned peers or server. We experimentally evaluate the performance of the system using live VoD traces captured from a large commercial IPTV network.
In the news
Misusing P2P Systems
BitTorrent is currently one of the most popular peer-to-peer systems. BitTorrent clients are widely spread all over the world and account for a large fraction of today's Internet traffic. In this paper, we show that BitTorrent can be exploited by misdirecting clients to send their traffic toward any host on the Internet. The volume of a BitTorrent swarm can thus be converted into firepower for launching a distributed denial-of-service attack that can exhaust the victim's resources, including access bandwidth and connection resources. We identify novel exploits of the BitTorrent system and conduct real-life experiments that demonstrate the feasibility and severity of such attacks. We characterize the volume, duration and spread of attack traffic observed in our experiments. Finally, we discuss possible fixes and the limits of both attack and defense approaches.
In the news
File-sharing sites are being subverted for web attacks at New Scientist, May 2007
P2P Networks Supplement Botnets at Slashdot, May 2007