Rarest first and choke algorithms are enough

Legout, Arnaud; Urvoy-Keller, Guillaume; Michiardi, Pietro

doi:10.1145/1177080.1177106

Cited by 302 publications

(254 citation statements)

References 22 publications

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“…In contrast, the second policy, called weight by maximum excess wait (EW), weights files not by the number of "excess-wait" requesting peers, but according to the longest excess wait time (i.e., time-in-system beyond the expected download time for a self-sustaining torrent), among such peers, with weight zero given if there is no such peer. 5 Finally, we define a policy called weight by product of the maximum excess wait and number of excess-wait peers (EW x NEWP) that uses the product of the two preceding metrics to determine its weights. Similar to RxW [19], this policy attempts to strike a balance between considerations of time in system, and number of requesters, in determining its weights.…”

Section: Prioritized Server Schedulingmentioning

confidence: 99%

Using Torrent Inflation to Efficiently Serve the Long Tail in Peer-Assisted Content Delivery Systems

2010

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Abstract.A peer-assisted content delivery system uses the upload bandwidth of its clients to assist in delivery of popular content. In peerassisted systems using a BitTorrent-like protocol, a content delivery server seeds the offered files, and active torrents form when multiple clients make closely-spaced requests for the same content. Scalability is achieved in the sense of being able to accommodate arbitrarily high request rates for individual files. Scalability with respect to the number of files, however, may be much more difficult to achieve, owing to a "long tail" of lukewarm or cold files for which the server may need to assume most or all of the delivery cost. This paper first addresses the question of how best to allocate server resources among multiple active torrents. We then propose new content delivery policies that use some of the available upload bandwidth from currently downloading clients to "inflate" torrents for files that would otherwise require substantial server bandwidth. Our performance results show that use of torrent inflation can substantially reduce download times, by more than 50% in some cases.

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Section: Prioritized Server Schedulingmentioning

confidence: 99%

Using Torrent Inflation to Efficiently Serve the Long Tail in Peer-Assisted Content Delivery Systems

2010

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“…Our aim is to come up with a solution that minimizes the content download time while at the same time improving collaboration by enforcing fair sharing among peers. As efficient and fair content sharing is targeted, we choose to adapt BitTorrent [1] as a file sharing protocol given its large usage and its known close to optimal performances in the wired Internet [13]. When data is distributed using BitTorrent, interested peers supply pieces of the data to other peers, reducing the burden on any individual peer, providing redundancy in the network, and reducing dependency on the original seed.…”

Section: Introductionmentioning

confidence: 99%

“…BitTorrent (see e.g., [1], [13]) is a scalable P2P content distribution protocol. Each client shares some of its upload bandwidth with other peers interested in the same content in order to increase the global system capacity.…”

Section: Introductionmentioning

confidence: 99%

Adapting BitTorrent to Wireless Ad Hoc Networks

Sbai

Barakat

Choi

et al.

Lecture Notes in Computer Science

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Abstract. BitTorrent is one of the Internet's most efficient content distribution protocols. It is known to perform very well over the wired Internet where end-to-end performance is almost guaranteed. However, in wireless ad hoc networks, many constraints appear as the scarcity of resources and their shared nature, which make running BitTorrent with its default configuration not lead to best performances. To these constraints it adds the fact that peers are both routers and end-users and that TCP-performance drops seriously with the number of hops. We show in this work that the neighbor selection mechanism in BitTorrent plays an important role in determining the performance of the protocol when deployed over a wireless ad hoc network. It is no longer efficient to choose and treat with peers independently of their location. A first solution is to limit the scope of the neighborhood. In this case, TCP connections are fast but there is no more diversity of pieces in the network: pieces propagate in a unique direction from the seed to distant peers. This prohibits peers from reciprocating data and leads to low sharing ratios and suboptimal utilization of network resources. To recover from these impairments, we propose an enhancement to BitTorrent which aims to minimize the time to download the content and at the same time to enforce cooperation among peers. Our solution considers a restricted neighborhood to reduce routing overhead and to improve throughput, while establishing few connections to remote peers to improve diversity of pieces. With the help of extensive NS-2 simulations, we show that these enhancements to BitTorrent significantly improve the file completion time while fully profiting from the incentives implemented in BitTorrent to enforce fair sharing.

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“…When selecting a piece, a peer chooses the piece with the least redundancy in its neighborhood. Rarest first is supposed to increase the diversity of pieces [6].…”

Section: Introductionmentioning

confidence: 99%

Revisiting P2P Content Sharing in Wireless Ad Hoc Networks

Sbai

Barakat

2009

Self-Organizing Systems

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Abstract. Classical content sharing applications like BitTorrent are not designed to run over wireless networks. When adapting them to these constrained networks, two main problems arise. On one hand, exchanging content pieces with far nodes results in an important routing overhead. On the other hand, it is necessary to send some content pieces to far nodes to increase the diversity of information in the network, which fosters reciprocity and parallel exchanges. In this paper, we study both of these problems and propose a joint solution for them. Unlike uni-metric approaches, our solution considers relevant performance metrics together as throughput, sharing and routing overhead. We define a new neighbor selection strategy that balances sharing and diversification efforts and decides on the optimal neighboring scope of a node. We also consider the diversification incentives problem and evaluates the impact of nodes' mobility on the P2P strategy to be adopted. Through extensive simulations, we prove that our solution achieves both better download time and sharing ratio than uni-metric solutions.

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Rarest first and choke algorithms are enough

Cited by 302 publications

References 22 publications

Using Torrent Inflation to Efficiently Serve the Long Tail in Peer-Assisted Content Delivery Systems

Using Torrent Inflation to Efficiently Serve the Long Tail in Peer-Assisted Content Delivery Systems

Adapting BitTorrent to Wireless Ad Hoc Networks

Revisiting P2P Content Sharing in Wireless Ad Hoc Networks

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