Results 1 - 10 of 177

Do Incentives Build Robustness in BitTorrent

by Michael Piatek, Tomas Isdal, Thomas Anderson, Arvind Krishnamurthy, Arun Venkataramani - In NSDI’07 , 2007
"... A fundamental problem with many peer-to-peer systems is the tendency for users to “free ride”—to consume resources without contributing to the system. The popular file distribution tool BitTorrent was explicitly designed to address this problem, using a tit-for-tat reciprocity strategy to provide po ..."
Abstract - Cited by 132 (11 self) - Add to MetaCart
A fundamental problem with many peer-to-peer systems is the tendency for users to “free ride”—to consume resources without contributing to the system. The popular file distribution tool BitTorrent was explicitly designed to address this problem, using a tit-for-tat reciprocity strategy to provide positive incentives for nodes to contribute resources to the swarm. While BitTorrent has been extremely successful, we show that its incentive mechanism is not robust to strategic clients. Through performance modeling parameterized by real world traces, we demonstrate that all peers contribute resources that do not directly improve their performance. We use these results to drive the design and implementation of BitTyrant, a strategic BitTorrent client that provides a median 70% performance gain for a 1 Mbit client on live Internet swarms. We further show that when applied universally, strategic clients can hurt average per-swarm performance compared to today’s BitTorrent client implementations. 1
(Show Context)

Can Internet Video-on-Demand Be Profitable

by Cheng Huang, Jin Li, Keith W. Ross - in Proceedings of ACM SIGCOMM , 2007
"... Video-on-demand in the Internet has become an immensely popular service in recent years. But due to its high bandwidth requirements and popularity, it is also a costly service to provide. We consider the design and potential benefits of peer-assisted video-on-demand, in which participating peers ass ..."
Abstract - Cited by 129 (7 self) - Add to MetaCart
Video-on-demand in the Internet has become an immensely popular service in recent years. But due to its high bandwidth requirements and popularity, it is also a costly service to provide. We consider the design and potential benefits of peer-assisted video-on-demand, in which participating peers assist the server in delivering VoD content. The assistance is done in such a way that it provides the same user quality experience as pure client-server distribution. We focus on the single-video approach, whereby a peer only redistributes a video that it is currently watching. Using a nine-month trace from a client-server VoD deployment for MSN Video, we assess what the 95 percentile server bandwidth costs would have been if a peer-assisted employment had been instead used. We show that peer-assistance can dramatically reduce server bandwidth costs, particularly if peers prefetch content when there is spare upload capacity in the system. We consider the impact of peer-assisted VoD on the cross-traffic among ISPs. Although this traffic is significant, if care is taken to localize the P2P traffic within the ISPs, we can eliminate the ISP cross traffic while still achieving important reductions in server bandwidth. We also develop a simple analytical model which captures many of the critical features of peer-assisted VoD, including its operational modes.
(Show Context)

Clustering and sharing incentives in bittorrent systems

by Arnaud Legout, Nikitas Liogkas, Eddie Kohler, Lixia Zhang - In Proc. of ACM SIGMETRICS ’07 , 2007
"... Peer-to-peer protocols play an increasingly instrumental role in Internet content distribution. Consequently, it is important to gain a full understanding of how these protocols behave in practice and how their parameters impact overall performance. We present the first experimental investigation of ..."
Abstract - Cited by 99 (7 self) - Add to MetaCart
Peer-to-peer protocols play an increasingly instrumental role in Internet content distribution. Consequently, it is important to gain a full understanding of how these protocols behave in practice and how their parameters impact overall performance. We present the first experimental investigation of the peer selection strategy of the popular BitTorrent protocol in an instrumented private torrent. By observing the decisions of more than 40 nodes, we validate three BitTorrent properties that, though widely believed to hold, have not been demonstrated experimentally. These include the clustering of similar-bandwidth peers, the effectiveness of BitTorrent’s sharing incentives, and the peers ’ high average upload utilization. In addition, our results show that BitTorrent’s new choking algorithm in seed state provides uniform service to all peers, and that an underprovisioned initial seed leads to the absence of peer clustering and less effective sharing incentives. Based on our observations, we provide guidelines for seed provisioning by content providers, and discuss a tracker protocol extension that addresses an identified limitation of the protocol. 1

One hop Reputations for Peer to Peer File Sharing Workloads

by Michael Piatek, Tomas Isdal, Arvind Krishnamurthy, Thomas Anderson
"... An emerging paradigm in peer-to-peer (P2P) networks is to explicitly consider incentives as part of the protocol design in order to promote good (or discourage bad) behavior. However, effective incentives are hampered by the challenges of a P2P environment, e.g. transient users and no central author ..."
Abstract - Cited by 68 (5 self) - Add to MetaCart
An emerging paradigm in peer-to-peer (P2P) networks is to explicitly consider incentives as part of the protocol design in order to promote good (or discourage bad) behavior. However, effective incentives are hampered by the challenges of a P2P environment, e.g. transient users and no central authority. In this paper, we quantify these challenges, reporting the results of a month-long measurement of millions of users of the BitTorrent file sharing system. Surprisingly, given BitTorrent’s popularity, we identify widespread performance and availability problems. These measurements motivate the design and implementation of a new, one hop reputation protocol for P2P networks. Unlike digital currency systems, where contribution information is globally visible, or titfor-tat, where no propagation occurs, one hop reputations limit propagation to at most one intermediary. Through trace-driven analysis and measurements of a deployment on PlanetLab, we find that limited propagation improves performance and incentives relative to BitTorrent. 1
(Show Context)

Understanding the power of pull-based streaming protocol: Can we do better

by Meng Zhang, Student Member, Qian Zhang, Senior Member, Lifeng Sun, Shiqiang Yang - IEEE JSAC , 2007
"... Abstract — Most of the real deployed peer-to-peer streaming systems adopt pull-based streaming protocol. In this paper, we demonstrate that, besides simplicity and robustness, with proper parameter settings, when the server bandwidth is above several times of the raw streaming rate, which is reasona ..."
Abstract - Cited by 67 (1 self) - Add to MetaCart
Abstract — Most of the real deployed peer-to-peer streaming systems adopt pull-based streaming protocol. In this paper, we demonstrate that, besides simplicity and robustness, with proper parameter settings, when the server bandwidth is above several times of the raw streaming rate, which is reasonable for practical live streaming system, simple pull-based P2P streaming protocol is nearly optimal in terms of peer upload capacity utilization and system throughput even without intelligent scheduling and bandwidth measurement. We also indicate that whether this near optimality can be achieved depends on the parameters in pull-based protocol, server bandwidth and group size. Then we present our mathematical analysis to gain deeper insight in this characteristic of pull-based streaming protocol. On the other hand, the optimality of pull-based protocol comes from a cost-tradeoff between control overhead and delay, that is, the protocol has either large control overhead or large delay. To break the tradeoff, we propose a pull-push hybrid protocol. The basic idea is to consider pull-based protocol as a highly efficient bandwidthaware multicast routing protocol and push down packets along the trees formed by pull-based protocol. Both simulation and real-world experiment show that this protocol is not only even more effective in throughput than pull-based protocol but also has far lower delay and much smaller overhead. And to achieve near optimality in peer capacity utilization without churn, the server bandwidth needed can be further relaxed. Furthermore, the proposed protocol is fully implemented in our deployed GridMedia system and has the record to support over 220,000 users simultaneously online. Index Terms — p2p streaming, pull-based, pull-push hybrid, capacity utilization, throughput, delay I.
(Show Context)

Antfarm: Efficient Content Distribution with Managed Swarms

by Ryan S. Peterson, Emin Gün Sirer
"... This paper describes Antfarm, a content distribution system based on managed swarms. A managed swarm couples peer-to-peer data exchange with a coordinator that directs bandwidth allocation at each peer. Antfarm achieves high throughput by viewing content distribution as a global optimization problem ..."
Abstract - Cited by 55 (1 self) - Add to MetaCart
This paper describes Antfarm, a content distribution system based on managed swarms. A managed swarm couples peer-to-peer data exchange with a coordinator that directs bandwidth allocation at each peer. Antfarm achieves high throughput by viewing content distribution as a global optimization problem, where the goal is to minimize download latencies for participants subject to bandwidth constraints and swarm dynamics. The system is based on a wire protocol that enables the Antfarm coordinator to gather information on swarm dynamics, detect misbehaving hosts, and direct the peers ’ allotment of upload bandwidth among multiple swarms. Antfarm’s coordinator grants autonomy and local optimization opportunities to participating nodes while guiding the swarms toward an efficient allocation of resources. Extensive simulations and a PlanetLab deployment show that the system can significantly outperform centralized distribution services as well as swarming systems such as BitTorrent. 1
(Show Context)

Is high-quality vod feasible using p2p swarming

by Siddhartha Annapureddy, Dinan Gunawardena - In Proc. of WWW , 2007
"... Peer-to-peer technologies are increasingly becoming the medium of choice for delivering media content, both professional and homegrown, to large user populations. Indeed, current P2P swarming systems have been shown to be very efficient for large-scale content distribution with few server resources. ..."
Abstract - Cited by 53 (2 self) - Add to MetaCart
Peer-to-peer technologies are increasingly becoming the medium of choice for delivering media content, both professional and homegrown, to large user populations. Indeed, current P2P swarming systems have been shown to be very efficient for large-scale content distribution with few server resources. However, such systems have been designed for generic file distribution and provide a limited user experience for viewing media content. For example, users need to wait to download the full video before they can start watching it. In general, the main challenge resides in designing systems that ensure that users can start watching a movie at any point in time, with small start-up times and sustainable playback rates. In this work, we address the issues of providing a Video-on-Demand (VoD) using P2P mesh-based networks. We show that providing high quality VoD using P2P is feasible using a combination of techniques including (a) network coding, (b) optimized resource allocation across different parts of the video, and (c) overlay topology management algorithms. Our evaluation also shows that systems that do not optimize in all these dimensions could significantly under-utilize the network resources resulting in poor VoD performance. We present our results based on simulations and a prototype implementation. Categories and Subject Descriptors
(Show Context)

The delicate tradeoffs in bittorrent-like file sharing protocol design

by Bin Fan - In ICNP , 2006
"... Abstract — The BitTorrent (BT) file sharing protocol is popular due to its scalability property and the incentive mechanism to reduce free-riding. However, in designing such P2P file sharing protocols, there is a fundamental “tussle ” between keeping peers, specially the more resourceful ones, in th ..."
Abstract - Cited by 50 (5 self) - Add to MetaCart
Abstract — The BitTorrent (BT) file sharing protocol is popular due to its scalability property and the incentive mechanism to reduce free-riding. However, in designing such P2P file sharing protocols, there is a fundamental “tussle ” between keeping peers, specially the more resourceful ones, in the system for as long as possible to help the system achieve better performance and allowing peers finish their download as quickly as possible. The current BT protocol represents only “one ” possible implementation in this whole design spectrum. In this paper, we characterize the “complete ” design space of BT-like protocols. We use fairness index to measure the fairness that incorporates the contribution peers make. We show that there is a wide range of design choices, ranging from optimizing the performance of file download, to optimizing the fairness measure. More importantly, we show that there is a simple and easily implementable design knob which can be used to choose a particular operating point in the design space. We then discuss different algorithms (centralized versus distributed) in realizing the design knob. We also carry out performance evaluation to quantify the merits and properties of the BT-like file sharing protocols. I.
(Show Context)

Peer-to-Peer Multimedia Streaming Using BitTorrent

by Purvi Shah, Jehan-françois Pâris - In IPCCC 2007 , 2007
"... We propose a peer-to-peer multimedia streaming solution based on the BitTorrent content-distribution protocol. Our proposal includes two modifications that allow it to deliver multimedia data on time. First, we replace the rarest-first chunk downloading policy of BitTorrent by a policy requiring pee ..."
Abstract - Cited by 36 (6 self) - Add to MetaCart
We propose a peer-to-peer multimedia streaming solution based on the BitTorrent content-distribution protocol. Our proposal includes two modifications that allow it to deliver multimedia data on time. First, we replace the rarest-first chunk downloading policy of BitTorrent by a policy requiring peers to download first the chunks that they will watch in the near future. Second, we introduce a new randomized tit-for-tat peer selection policy that gives free tries to a larger number of peers and lets them participate sooner in the media distribution. Our simulations indicate that both changes are required to achieve a good streaming quality. 1.
(Show Context)

Leveraging BitTorrent for end host measurements

by Tomas Isdal, Michael Piatek, Arvind Krishnamurthy, Thomas Anderson - in Proc. PAM , 2007
"... Abstract. Traditional methods of conducting measurements to end hosts require sending unexpected packets to measurement targets. Although existing techniques can ascertain end host characteristics accurately, their use in large-scale measurement studies is hindered by the fact that unexpected traffi ..."
Abstract - Cited by 27 (6 self) - Add to MetaCart
Abstract. Traditional methods of conducting measurements to end hosts require sending unexpected packets to measurement targets. Although existing techniques can ascertain end host characteristics accurately, their use in large-scale measurement studies is hindered by the fact that unexpected traffic can trigger alarms in common intrusion detection systems, often resulting in complaints from administrators. We describe BitProbes, a measurement system that works around this challenge. By coordinated participation in the popular peer-to-peer BitTorrent system, BitProbes is able to unobtrusively measure bandwidth capacity, latency, and topology information for ∼500,000 end hosts per week from only eight vantage points at the University of Washington. To date, our measurements have not generated a single complaint in spite of their wide coverage. 1
(Show Context)