bittorrent location-aware protocol 1_0 specification.mht

关于ＢＴ的协议文档

formatted as in the HTTP/HTTPS GET request in a <A class=3D"external =
text"=20
title=3Dhttp://wiki.theory.org/BitTorrentSpecification#byte_strings=20
href=3D"http://wiki.theory.org/BitTorrentSpecification#byte_strings"=20
rel=3Dnofollow>string</A> form. The returned peers will be sorted in =
ascending=20
order by distance to the requester. A compromise could be made here. If =
there=20
are no peers having the whole torrent in the server response, the =
tracker may=20
substitute the last positions of the peers list with the closest =
seeders. With=20
such a server behavior a seeder can detect clustered peers with no =
available=20
seeders and make a compromise with the distance and distribute it to a =
peer of=20
the cluster. Even if the connecting peer does not support the BitTorrent =

Location-aware Protocol 1.0, the tracker may still check each =
peer=E2=80=99s location in=20
one of those IP address location databases and return the closest ones =
first.=20
</P>
<DIV class=3Deditsection style=3D"FLOAT: right; MARGIN-LEFT: 5px">[<A=20
title=3D"Edit section: New Peer Notification Message"=20
href=3D"http://wiki.theory.org/index.php?title=3DBitTorrent_Location-awar=
e_Protocol_1.0_Specification&amp;action=3Dedit&amp;section=3D11">edit</A>=
]</DIV><A=20
name=3DNew_Peer_Notification_Message></A>
<H3>New Peer Notification Message </H3>
<P>When the tracker returns the list of peers to a peer <B>A</B>, these =
are the=20
closest peers and there is a maximum distance. If a new peer connects to =
the=20
tracker and its distance to peer <B>A</B> is less than the maximum =
distance, the=20
tracker will send to peer <B>A</B> a message notifying that a new closer =
peer=20
had connected. This is called <B>New Peer Notification Message</B> and =
it is a=20
<A class=3D"external text"=20
title=3Dhttp://wiki.theory.org/BitTorrentSpecification#dictionaries=20
href=3D"http://wiki.theory.org/BitTorrentSpecification#dictionaries"=20
rel=3Dnofollow>bencoded dictionary</A> with the following key / value =
pairs: </P>
<UL>
  <LI><B>info hash</B>: 20-byte SHA1 hash of the value of the info key =
from the=20
  <A class=3D"external text"=20
  =
title=3Dhttp://wiki.theory.org/BitTorrentSpecification#Metainfo_File_Stru=
cture=20
  =
href=3D"http://wiki.theory.org/BitTorrentSpecification#Metainfo_File_Stru=
cture"=20
  rel=3Dnofollow>Metainfo file</A>. Note that the value will be a =
bencoded=20
  dictionary, given the definition of the info key.=20
  <LI><B>peer id</B>: <A class=3D"external text"=20
  title=3Dhttp://wiki.theory.org/BitTorrentSpecification#peer_id=20
  href=3D"http://wiki.theory.org/BitTorrentSpecification#peer_id"=20
  rel=3Dnofollow>peer's self-selected ID</A>, as described as described =
in the=20
  BitTorrent protocol specification.=20
  <LI><B>ip</B>: peer's IP address (either IPv6 or IPv4) or DNS name (<A =

  class=3D"external text"=20
  title=3Dhttp://wiki.theory.org/BitTorrentSpecification#byte_strings=20
  href=3D"http://wiki.theory.org/BitTorrentSpecification#byte_strings"=20
  rel=3Dnofollow>string</A>).=20
  <LI><B>port</B>: peer's port number (<A class=3D"external text"=20
  title=3Dhttp://wiki.theory.org/BitTorrentSpecification#integers=20
  href=3D"http://wiki.theory.org/BitTorrentSpecification#integers"=20
  rel=3Dnofollow>integer</A>). </LI></UL>
<P>If a peer receives a new peer notification message and does not serve =
the=20
current torrent he should respond in plain text =E2=80=9C<B>11:not =
serving</B>=E2=80=9D. If he=20
is serving the torrent the response should be =
=E2=80=9C<B>7:serving</B>=E2=80=9D. After this the=20
peer should close the connection. With this implementation the tracker =
can=20
filter out peers not serving the torrent anymore. </P>
<DIV class=3Deditsection style=3D"FLOAT: right; MARGIN-LEFT: 5px">[<A=20
title=3D"Edit section: Peer-peer Handshake"=20
href=3D"http://wiki.theory.org/index.php?title=3DBitTorrent_Location-awar=
e_Protocol_1.0_Specification&amp;action=3Dedit&amp;section=3D12">edit</A>=
]</DIV><A=20
name=3DPeer-peer_Handshake></A>
<H3>Peer-peer Handshake </H3>
<P>In a handshake between peers the <A class=3D"external text"=20
title=3Dhttp://wiki.theory.org/BitTorrentSpecification#Handshake=20
href=3D"http://wiki.theory.org/BitTorrentSpecification#Handshake"=20
rel=3Dnofollow>pstr</A> will have a value =E2=80=9C<B>BitTorrent =
Location-aware Protocol=20
1.0</B>=E2=80=9D. The <A class=3D"external text"=20
title=3Dhttp://wiki.theory.org/BitTorrentSpecification#Reserved_Bytes=20
href=3D"http://wiki.theory.org/BitTorrentSpecification#Reserved_Bytes"=20
rel=3Dnofollow>reserved bit</A> is 21. </P>
<DIV class=3Deditsection style=3D"FLOAT: right; MARGIN-LEFT: 5px">[<A=20
title=3D"Edit section: Location Message"=20
href=3D"http://wiki.theory.org/index.php?title=3DBitTorrent_Location-awar=
e_Protocol_1.0_Specification&amp;action=3Dedit&amp;section=3D13">edit</A>=
]</DIV><A=20
name=3DLocation_Message></A>
<H3>Location Message </H3>
<P>If the two peers had declared the BitTorrent Location-aware Protocol =
1.0,=20
both of them send immediately after the <A class=3D"external text"=20
title=3Dhttp://wiki.theory.org/BitTorrent_Location-aware_Protocol_1.0_Spe=
cification#Peer-peer_Handshake=20
href=3D"http://wiki.theory.org/BitTorrent_Location-aware_Protocol_1.0_Spe=
cification#Peer-peer_Handshake"=20
rel=3Dnofollow>handshake</A> and before the <A class=3D"external text"=20
title=3Dhttp://wiki.theory.org/BitTorrentSpecification#bitfield:_.3Clen.3=
D0001.2BX.3E.3Cid.3D5.3E.3Cbitfield.3E=20
href=3D"http://wiki.theory.org/BitTorrentSpecification#bitfield:_.3Clen.3=
D0001.2BX.3E.3Cid.3D5.3E.3Cbitfield.3E"=20
rel=3Dnofollow>bitfield</A> their latitude and longitude in a location =
message.=20
The format is: <I>&lt;latitude&gt;&lt;longitude&gt;</I>. Both, the =
latitude and=20
longitude, will be formatted as within the tracker response. When a peer =

receives other peer=E2=80=99s location and it differs from the one =
supplied by the=20
tracker, he must reply with =E2=80=9C<B>17:Location =
Mismatch</B>=E2=80=9D and drop the=20
connection. </P>
<DIV class=3Deditsection style=3D"FLOAT: right; MARGIN-LEFT: 5px">[<A=20
title=3D"Edit section: Implementation in the Client and the Tracker"=20
href=3D"http://wiki.theory.org/index.php?title=3DBitTorrent_Location-awar=
e_Protocol_1.0_Specification&amp;action=3Dedit&amp;section=3D14">edit</A>=
]</DIV><A=20
name=3DImplementation_in_the_Client_and_the_Tracker></A>
<H2>Implementation in the Client and the Tracker </H2>
<P>When implementing the BitTorrent Location-aware Protocol 1.0 in a =
client=20
side, the decisions from what peer to download what are complex and =
should go=20
under testing to find out where the performance is best. This is =
definitely not=20
an easy task, but with the existence of so many clients, some of them =
open=20
source, the upgrade should be possible. </P>
<DIV class=3Deditsection style=3D"FLOAT: right; MARGIN-LEFT: 5px">[<A=20
title=3D"Edit section: Related Documents"=20
href=3D"http://wiki.theory.org/index.php?title=3DBitTorrent_Location-awar=
e_Protocol_1.0_Specification&amp;action=3Dedit&amp;section=3D15">edit</A>=
]</DIV><A=20
name=3DRelated_Documents></A>
<H2>Related Documents </H2>
<UL>
  <LI><A class=3D"external text"=20
  title=3Dhttp://wiki.theory.org/BitTorrentSpecification=20
  href=3D"http://wiki.theory.org/BitTorrentSpecification" =
rel=3Dnofollow>Bittorrent=20
  Protocol Specification v1.0</A> </LI></UL>
<DIV class=3Deditsection style=3D"FLOAT: right; MARGIN-LEFT: 5px">[<A=20
title=3D"Edit section: Change Log"=20
href=3D"http://wiki.theory.org/index.php?title=3DBitTorrent_Location-awar=
e_Protocol_1.0_Specification&amp;action=3Dedit&amp;section=3D16">edit</A>=
]</DIV><A=20
name=3DChange_Log></A>
<H2>Change Log </H2>
<P>Put your changes below this line, so that the most recent changes =
appear=20
first. </P>
<UL>
  <LI>April 25, 2007 - Initial Publication - by Boian V Petkantchin.=20
  <UL>
    <LI>Contact: sogartary at yahoo.com </LI></UL></LI></UL><!-- Saved =
in parser cache with key mw-to:pcache:idhash:1668-0!1!0!!en!2 and =
timestamp 20070718154832 -->
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