| 1 | BEP: 16 |
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| 2 | Title: Superseeding |
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| 3 | Version: $Revision$ |
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| 4 | Last-Modified: $Date$ |
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| 5 | Author: John Hoffman <theshadow@degreez.net> |
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| 6 | Status: Draft |
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| 7 | Type: Standards Track |
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| 8 | Created: 25-Feb-2008 |
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| 9 | Post-History: |
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| 10 | |
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| 11 | The super-seed feature in S-5.5 and on is a new seeding algorithm designed to help |
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| 12 | a torrent initiator with limited bandwidth "pump up" a large torrent, reducing the |
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| 13 | amount of data it needs to upload in order to spawn new seeds in the torrent. |
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| 14 | |
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| 15 | When a seeding client enters "super-seed mode", it will not act as a standard seed, |
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| 16 | but masquerades as a normal client with no data. As clients connect, it will then |
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| 17 | inform them that it received a piece -- a piece that was never sent, or if all |
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| 18 | pieces were already sent, is very rare. This will induce the client to attempt to |
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| 19 | download only that piece. |
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| 20 | |
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| 21 | When the client has finished downloading the piece, the seed will not inform it of |
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| 22 | any other pieces until it has seen the piece it had sent previously present on at |
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| 23 | least one other client. Until then, the client will not have access to any of the |
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| 24 | other pieces of the seed, and therefore will not waste the seed's bandwidth. |
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| 25 | |
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| 26 | This method has resulted in much higher seeding efficiencies, by both inducing |
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| 27 | peers into taking only the rarest data, reducing the amount of redundant data sent, |
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| 28 | and limiting the amount of data sent to peers which do not contribute to the swarm. |
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| 29 | Prior to this, a seed might have to upload 150% to 200% of the total size of a |
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| 30 | torrent before other clients became seeds. However, a large torrent seeded with a |
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| 31 | single client running in super-seed mode was able to do so after only uploading |
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| 32 | 105% of the data. This is 150-200% more efficient than when using a standard seed. |
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| 33 | |
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| 34 | Super-seed mode is *NOT* recommended for general use. While it does assist in the |
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| 35 | wider distribution of rare data, because it limits the selection of pieces a |
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| 36 | client can downlad, it also limits the ability of those clients to download data |
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| 37 | for pieces they have already partially retrieved. Therefore, super-seed mode is |
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| 38 | only recommended for initial seeding servers. |
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| 39 | |
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| 40 | |
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| 41 | |
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| 42 | .. |
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| 43 | Local Variables: |
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| 44 | mode: indented-text |
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| 45 | indent-tabs-mode: nil |
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| 46 | sentence-end-double-space: t |
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| 47 | fill-column: 70 |
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| 48 | coding: utf-8 |
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| 49 | End: |
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| 50 | |
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