Paircoding: Improving File Sharing Using Sparse Network Codes

Ortolf, Christian; Schindelhauer, Christian; Vater, Arne

doi:10.1109/iciw.2009.16

Cited by 8 publications

(12 citation statements)

References 17 publications

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“…To avoid this problem, our C4 utilizes sparse RLNC proposed in [28] to control overhead. Given k original data packets as one generation, sparse RLNC first randomly chooses p data packets, then performs RLNC on these p packets to generate a coded packet.…”

Section: Implementation Details Of Our C4mentioning

confidence: 99%

C4: A new paradigm for providing incentives in multi-hop wireless networks

Zhang

Zhu

Song

et al. 2011

2011 Proceedings IEEE INFOCOM

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Abstract-For a multi-hop wireless network (MWN) consisting of mobile nodes controlled by independent self-interested users, incentive mechanism is essential for motivating mobile nodes to cooperate and forward packets for each other. Existing solutions such as barter based, virtual-currency based and reputation based schemes are either less effective or incur high imple mentation costs, and therefore do not fit well with the unique requirements of MWNs. In this paper, we propose a nove� and promising incentive paradigm, Controlled Coded packets as vlrtual Commodity Currency (C4), to induce cooperative behaviors in MWNs. In our C4, through introducing several techniques from network coding, coded information packets are utilized as a new kind of virtual currency to facilitate packet/service exchanges among self-interested nodes in a MWN. Since the virtual currency implemented in this way also carries useful �ata informat!on, it is the counterpart of the so-called commodIty currency III the physical world, and the overhead brought by C4 is extremely small compared to traditional schemes. We theoretically show that C4 is perfectly efficient to support MWNs with broadcast and multicast traffics. For pure unicast communications, by adjusting the grouping parameter, our C4 provides a systematic way to smoothly trade incentive effectiveness for implementation cost, and traditional barter based and virtual-currency based schemes are just two extreme cases of C4. We also show that when our C4 is combined with the social network formed by mobile users in the MWN, the implementation costs can be further reduced without sacrificing incentive effectiveness.

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Section: Implementation Details Of Our C4mentioning

confidence: 99%

C4: A new paradigm for providing incentives in multi-hop wireless networks

Zhang

Zhu

Song

et al. 2011

2011 Proceedings IEEE INFOCOM

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“…Then, any two peers with progress 1 2 can decode the file and thus have full availability of the file. Using this technique we have proved in [10] the following theorem for the scenario depicted in Figure 3. …”

Section: Paircodingmentioning

confidence: 99%

“…We have presented Paircoding [10] as a sparse form of Network Coding. Here, each code block is a linear combination of at most two original blocks.…”

Section: Paircodingmentioning

confidence: 99%

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Classifying peer-to-peer network coding schemes

Ortolf

Schindelhauer

Vater³

2009

Proceedings of the Twenty-First Annual Symposium on Parallelism in Algorithms and Architectures

Self Cite

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Modern peer-to-peer file sharing systems distribute large files among peers using block partitioning. Blocks can be redistributed by a peer even before the whole file is available which highly decreases the distribution time. All peer-topeer networks face the problem of dynamic participation of the peers and dynamic bandwidth in the network. A leaving peer can cause an unrecoverable loss of blocks and obstruct further downloads of the file. Furthermore, the choice which block needs to be sent to which peer is a hard question. A random choice leads to the coupon collector problem which decreases the transmission rate. Filesharing networks like BitTorrent or Splitstream face such problems.Network Coding overcomes this problem by using error redundant codes of all blocks of the file. An efficient randomized variant of it, Practical Network Coding, transmits and recombines random linear combinations of the blocks of the partitioned file. As soon as enough linear combinations have been gathered, the original file can be decoded by a matrix operation, optimizing the network flow in any peer-to-peer network.All known Network Coding schemes, however, suffer from a quadratic cost of read/write disk operations for both encoding and decoding. Since there is an increasing gap between the speed of mass storage devices and the main memory, this poses an obstacle to a wider use of Network Coding schemes.In this paper we present and investigate new network coding schemes, which form a compromise between Network Coding and uncoded block transfer schemes like BitTorrent. These schemes, called Paircoding and Treecoding have smaller read/write costs for encoding and decoding than Practical Network Coding and higher throughput than BitTorrent.We develop a new framework for comparing the throughput of data (performance) of such peer-to-peer file sharing systems and classify these systems, as well as a BitTorrent variant which uses forward error correction. The dynamPermission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. ics of peer-to-peer networks are described by a round model where the set of participating peers and their link quality changes after each round. The framework compares two schemes for all possible dynamic scenarios. If the transmission rate of scheme A is at least as well as scheme B, then we say A performs as well as B. If this is the case and there is a scenario where A is better than B, we say A outperforms B. We show that all of our proposed coding schemes outperform BitTorrent, while being outperformed by Network Coding.This leads to a hierarchy, where BitTorrent is the worst performer and Network Coding is the best performer regarding throughput. Regardin...

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“…In [11] we have introduced Pair Coding. We have shown that it performs at least as good as BitTorrent with a constant factor increase in complexity.…”

Section: Previous Workmentioning

confidence: 99%

Tree network coding for peer-to-peer networks

Vater

Schindelhauer

Ortolf

2010

Proceedings of the Twenty-Second Annual ACM Symposium on Parallelism in Algorithms and Architectures

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Partitioning is the dominant technique to transmit large files in peer-to-peer networks. A peer can redistribute each part immediately after its download. BitTorrent combines this approach with incentives for uploads and has thereby become the most successful peer-to-peer network. However, BitTorrent fails if files are unpopular and are distributed by irregularly participating peers. It is known that Network Coding always provides the optimal data distribution, referred as optimal performance. Yet, for encoding or decoding a single code block the whole file must be read and users are not willing to read O(n 2 ) data blocks from hard disk for sending n message blocks. We call this the disk read/write complexity of an encoding.It is an open question whether fast network coding schemes exist. In this paper we present a solution for simple communication patterns. Here, in a round model each peer can send a limited amount of messages to other peers. We define the depth of this directed acyclic communication graph as the maximum path length (not counting the rounds). In our online model each peer knows the bandwidth of its communication links for the current round, but neither the existence nor the weight of links in future rounds.In this paper we analyze BitTorrent, Network Coding, Tree Coding, and Tree Network Coding. We show that the average encoding and decoding complexity of Tree Coding is bounded by O(kn log 2 n) disk read/write-operations where k is the number of trees and n the number of data blocks.Tree Coding has perfect performance in communication networks of depth two with a disk read/write complexity of O(pnt log 3 n) where p is the number of peers, t is the number of rounds, and n is the number of data blocks. For arbitrary networks Tree Coding performs optimally using 2(δ + 1) t−1 p log 2 n trees which results in a read/write complexity of O((δ + 1) t−1 n log 3 n) for t rounds and in-degree δ. * Partly supported by DFG research fund Schi 372/5-1.

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Paircoding: Improving File Sharing Using Sparse Network Codes

Cited by 8 publications

References 17 publications

C4: A new paradigm for providing incentives in multi-hop wireless networks

C4: A new paradigm for providing incentives in multi-hop wireless networks

Classifying peer-to-peer network coding schemes

Tree network coding for peer-to-peer networks

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