Experimental Assessment of BitTorrent Completion Time in Heterogeneous TCP/uTP swarms

BitTorrent, one of the most widespread used P2P application for file-sharing, recently got rid of TCP by introducing an application-level congestion control protocol named uTP. The aim of this new protocol is to efficiently use the available link capacity, while minimizing its interference with the rest of user traffic (e.g., Web, VoIP and gaming) sharing the same access bottleneck. In this paper we perform an experimental study of the impact of uTP on the torrent completion time, the metric that better captures the user experience. We run BitTorrent applications in a flash crowd scenario over a dedicated cluster platform, under both homogeneous and heterogeneous swarm population. Experiments show that an all-uTP swarms have shorter torrent download time with respect to all-TCP swarms. Interestingly, at the same time, we observe that even shorter completion times can be achieved under careful mixtures of TCP and uTP traffic.Comment: 14 pages, under submissio

Delay-based congestion control: Flow vs. BitTorrent swarm perspectives

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Through a router darkly: how new American copyright enforcement initiatives may hinder economic development, net neutrality and creativity

On November 1, 2012, Russia enacted a law putatively aiming to protect Russian children from pedophiles. This law authorizes deep packet inspection (DPI), a method used for monitoring, filtering and shaping internet traffic, which has heightened concerns among many leading privacy groups. These groups are concerned with how the government will use such an intrusive method in prosecuting child predators. Central to this concern is DPI’s capability to allow the Russian government to peer into any citizens’ unencrypted internet traffic and monitor, copy, or even alter the traffic as it moves to its destination. The unresolved question is whether the government’s use of DPI will be restrained and utilized primarily to thwart child predators, or whether it will be expanded to lay the groundwork for a new era of national censorship. Although the United States has not yet adopted similar tactics in regulating its citizens’ internet use, Russia’s implementation of the new DPI monitoring and filtering system will provide an educational opportunity for both privacy advocates and policymakers

Harnessing the power of BitTorrent for distributed denial-of-service attacks

BitTorrent is a popular peer-to-peer (P2P) file-sharing protocol that utilizes a central server, known as a \u27tracker\u27, to coordinate connections between peers in a \u27swarm\u27, a term used to describe a Bit Torrent ad-hoc file sharing network. The tracker of a swarm is specified by the original file distributor and trusted unconditionally by peers in the swarm. This central point of control provides an opportunity for a file distributor to deploy a modified tracker to provide peers in a swarm with malicious coordination data, directing peer connection traffic toward an arbitrary target machine on an arbitrary service port. Although such an attack does not generate huge amount of attack traffic, it would set up many connections with the victim server successfully, which could cause serious denial-of-service by exhausting the victim server\u27s connection resource. In this paper, we present and demonstrate such an attack that is entirely tracker-based, requiring no modifications to Bit Torrent client software and could be deployed by an attacker right now. The results from both emulation and real-world experiments show the applicability of this attack. Due to the skyrocketing popularity of Bit Torrent and numerous large-scale swarms existed in the Internet, Bit Torrent swarms provide an intriguing platform for launching distributed denial-of-service (DDoS) attacks based on connection exhaustion. Copyright (C) 2010 John Wiley & Sons, Ltd

Serving Niche Video-on-Demand Content in a Managed P2P Environment

A limitation of existing P2P VoD services is their inability to support efficient streamed access to niche content that has relatively small demand. This limitation stems from the poor performance of P2P when the number of peers sharing the content is small. In this paper, we propose a new provider-managed P2P VoD framework for efficient delivery of niche content based on two principles: reserving small portions of peers' storage and upload resources, as well as using novel, weighed caching techniques. We demonstrate through analytical analysis, simulations, and experiments on planetlab that our architecture can provide high streaming quality for niche content. In particular, we show that our architecture increases the catalog size by up to $40\%$ compared to standard P2P VoD systems, and that a weighted cache policy can reduce the startup delay for niche content by a factor of more than three

Efficient Content Distribution With Managed Swarms

Content distribution has become increasingly important as people have become more reliant on Internet services to provide large multimedia content. Efficiently distributing content is a complex and difficult problem: large content libraries are often distributed across many physical hosts, and each host has its own bandwidth and storage constraints. Peer-to-peer and peer-assisted download systems further complicate content distribution. By contributing their own bandwidth, end users can improve overall performance and reduce load on servers, but end users have their own motivations and incentives that are not necessarily aligned with those of content distributors. Consequently, existing content distributors either opt to serve content exclusively from hosts under their direct control, and thus neglect the large pool of resources that end users can offer, or they allow end users to contribute bandwidth at the expense of sacrificing complete control over available resources. This thesis introduces a new approach to content distribution that achieves high performance for distributing bulk content, based on managed swarms. Managed swarms efficiently allocate bandwidth from origin servers, in-network caches, and end users to achieve system-wide performance objectives. Managed swarming systems are characterized by the presence of a logically centralized coordinator that maintains a global view of the system and directs hosts toward an efficient use of bandwidth. The coordinator allocates bandwidth from each host based on empirical measurements of swarm behavior combined with a new model of swarm dynamics. The new model enables the coordinator to predict how swarms will respond to changes in bandwidth based on past measurements of their performance. In this thesis, we focus on the global objective of maximizing download bandwidth across end users in the system. To that end, we introduce two algorithms that the coordinator can use to compute efficient allocations of bandwidth for each host that result in high download speeds for clients. We have implemented a scalable coordinator that uses these algorithms to maximize system-wide aggregate bandwidth. The coordinator actively measures swarm dynamics and uses the data to calculate, for each host, a bandwidth allocation among the swarms competing for the host's bandwidth. Extensive simulations and a live deployment show that managed swarms significantly outperform centralized distribution services as well as completely decentralized peer-to-peer systems