imported>InternetArchiveBot：补救19个来源，并将0个来源标记为失效。) #IABot (v2.0.8

2021-02-07T23:40:01Z

补救19个来源，并将0个来源标记为失效。) #IABot (v2.0.8

新页面

{{noteTA
|G1=IT
}}
'''Micro Transport Protocol'''或稱'''µTP'''是一個由[[µTorrent]]完成的[[BitTorrent (协议)|BitTorrent協定]]。

它原本被設計用於當BitTorrent下載與一般應用程式衝突時，自動降低BitTorrent的點對點下載速率<ref name="forum.bittorrent.org">{{Cite web |url=http://forum.bittorrent.org/viewtopic.php?pid=762#p762 |title=存档副本 |accessdate=2010-02-14 |archive-date=2010-03-01 |archive-url=https://web.archive.org/web/20100301125306/http://forum.bittorrent.org/viewtopic.php?pid=762#p762 |dead-url=no }}</ref>。例如，它應能自動調節BitTorrent下載與瀏覽網頁所用頻寬。

希臘字母''mu''可能不是那麼好打出，µTP通常被寫為uTP。

==開發==

µTP是由[[BitTorrent公司]]開發，但沒有投入更廣泛的網路社群。<ref>{{cite web |url=http://forum.utorrent.com/viewtopic.php?id=59150 |title=存档副本 |accessdate=2010-02-14 |deadurl=yes |archiveurl=https://web.archive.org/web/20130607090621/http://forum.utorrent.com/viewtopic.php?id=59150 |archivedate=2013-06-07 }}</ref>它首先於µTorrent 1.8.x beta加入，並於[[µTorrent]] 1.9 Alpha中正式對外公開。<ref>{{Cite web |url=http://arstechnica.com/news.ars/post/20081201-utorrents-switch-to-udp-and-why-the-sky-isnt-falling.html |title=µTorrent's switch to UDP and why the sky isn't falling |accessdate=2010-02-14 |archive-date=2009-01-24 |archive-url=https://web.archive.org/web/20090124014846/http://arstechnica.com/news.ars/post/20081201-utorrents-switch-to-udp-and-why-the-sky-isnt-falling.html |dead-url=no }}</ref><ref>{{Cite web |url=http://www.thinkbroadband.com/news/3807-utorrent-shifts-towards-udp-to-make-it-work-better.html |title=uTorrent shifts towards UDP to make it work better |accessdate=2010-02-14 |archive-date=2016-06-04 |archive-url=https://web.archive.org/web/20160604062126/http://www.thinkbroadband.com/news/3807-utorrent-shifts-towards-udp-to-make-it-work-better.html |dead-url=no }}</ref>

在µTorrent中加入的µTP功能被分割到libutp函式庫中，並以[[MIT許可證]]發布。<ref>{{Cite web |url=http://forum.utorrent.com/viewtopic.php?id=76640 |title=libutp, an open source implementation of µTP, has now been released |accessdate=2011-04-13 |archive-date=2011-01-23 |archive-url=https://web.archive.org/web/20110123183649/http://forum.utorrent.com/viewtopic.php?id=76640 |dead-url=no }}</ref><ref>{{Cite web |url=https://github.com/bittorrent/libutp |title=存档副本 |accessdate=2011-04-13 |archive-date=2021-01-25 |archive-url=https://web.archive.org/web/20210125065734/https://github.com/bittorrent/libutp |dead-url=no }}</ref>

第一個支援µTP的[[自由軟體]]客戶端是[[KTorrent]] 4.0。<ref>{{Cite web |url=http://torrentfreak.com/ktorrent-first-bittorrent-client-to-adopt-open-source-utp-100528/ |title=存档副本 |accessdate=2011-04-16 |archive-date=2020-11-22 |archive-url=https://web.archive.org/web/20201122063741/https://torrentfreak.com/ktorrent-first-bittorrent-client-to-adopt-open-source-utp-100528/ |dead-url=no }}</ref><ref>{{Cite web |url=http://ktorrent.org/?q=node%2F42 |title=存档副本 |accessdate=2021-02-07 |archive-date=2018-09-16 |archive-url=https://web.archive.org/web/20180916172319/http://ktorrent.org/?q=node%2F42 |dead-url=yes }}</ref>{{link-en|libtorrent}}（一个实现BitTorrent协议的API）目前在一个开发分支中实现了不完全的µTP协议。<ref>{{Cite web |url=https://libtorrent.svn.sourceforge.net/svnroot/libtorrent/branches/libtorrent_utp/ |title=存档副本 |accessdate=2011-04-16 |archive-date=2012-03-03 |archive-url=https://web.archive.org/web/20120303145807/https://libtorrent.svn.sourceforge.net/svnroot/libtorrent/branches/libtorrent_utp/ |dead-url=yes }}</ref><ref>http://libtorrent.svn.sourceforge.net/viewvc/libtorrent/branches/libtorrent_utp/{{Dead link|date=2018年8月 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref>{{Cite web |url=http://code.google.com/p/libtorrent/issues/detail?id=6 |title=存档副本 |accessdate=2011-04-16 |archive-date=2016-03-19 |archive-url=https://web.archive.org/web/20160319192333/https://code.google.com/p/libtorrent/issues/detail?id=6 |dead-url=no }}</ref> Azureus（現在叫做[[Vuze]]）Bittorrent客戶端也支援µTP（在微軟Windows和MAC OS X 10.5或更新版本上的Azureus 4.5.0.5以後）。<ref>{{Cite web |url=http://azureus.sourceforge.net/plugin_details.php?plugin=azutp |title=存档副本 |accessdate=2011-04-16 |archive-date=2012-05-15 |archive-url=https://web.archive.org/web/20120515163105/http://azureus.sourceforge.net/plugin_details.php?plugin=azutp |dead-url=no }}</ref> [[Transmission]]從2.30版開始支援µTP。<ref>{{Cite web |url=https://trac.transmissionbt.com/ticket/2338 |title=存档副本 |access-date=2011-04-16 |archive-url=https://web.archive.org/web/20170805181943/https://trac.transmissionbt.com/ticket/2338 |archive-date=2017-08-05 |dead-url=yes }}</ref>

自由软件社区中有人认为，如果将µTP的拥塞控制加入现有的TCP协议中，将比为某个应用程序专门设计一种机制能更好的达成uTP的开发目标。<ref>{{Cite web |url=http://forum.bittorrent.org/viewtopic.php?pid=764#p764 |title=存档副本 |accessdate=2010-02-14 |archive-date=2012-03-01 |archive-url=https://web.archive.org/web/20120301060154/http://forum.bittorrent.org/viewtopic.php?pid=764#p764 |dead-url=no }}</ref>另一些人提出，尽管µTP协议有许多优点，但由于现有的TCP协议与操作系统内核紧密结合，在其中加入新的功能特性需要很长时间才能在应用程序中发挥作用。{{Citation needed|date=January 2010}}

==運作==

µTP由兩個部分所組成：一个框架机制，以及一种相比TCP协议较低侵略性的拥塞控制算法。
===µTP的框架机制===

µTP在UDP分组中以自己的框架机制来储存数据。这种机制与TCP具有大致相同的功能（同样带有时间戳和使用选择性确认分组SACK），但以一种独特的方式实现。

有评论认为µTP的框架机制有诸多不完善之处。<ref>{{Cite web |url=http://forum.bittorrent.org/viewtopic.php?id=131 |title=存档副本 |accessdate=2010-02-14 |archive-date=2013-08-04 |archive-url=https://web.archive.org/web/20130804191429/http://forum.bittorrent.org/viewtopic.php?id=131 |dead-url=no }}</ref>

===µTP的拥塞控制===

µTP的拥塞控制被称为[[LEDBAT]]，旨在减少当延迟不严重时，应用程序使用µTP来最大化可用带宽造成的延迟。<ref name="forum.bittorrent.org"/><ref>{{Cite web |url=http://searchnetworking.techtarget.com.au/articles/27957-Torrents-of-Disruption-on-the-Way- |title=Technical information about UDP |access-date=2008-12-23 |archive-url=https://web.archive.org/web/20090512123108/http://searchnetworking.techtarget.com.au/articles/27957-Torrents-of-Disruption-on-the-Way- |archive-date=2009-05-12 |dead-url=yes }}</ref>此外，µTP的拥塞控制器提供的信息可用于选择TCP连接的传输率。<ref>{{cite web
|url = http://forum.utorrent.com/viewtopic.php?pid=377209#p377209
|date = 2008-11-26
|title = Post by developer "Greg Hazel" in thread "µTorrent 1.9 alpha"
|accessdate = 2009-03-08
|deadurl = yes
|archiveurl = https://web.archive.org/web/20090208093326/http://forum.utorrent.com/viewtopic.php?pid=377209#p377209
|archivedate = 2009-02-08
}}</ref>

IETF在互联网草案中描述了LEDBAT算法，<ref>{{cite web
| url = http://tools.ietf.org/id/draft-shalunov-ledbat-congestion-00.txt
| date = 2009-03-04
| title = Low Extra Delay Background Transport (LEDBAT)
| accessdate = 2009-12-01
| archive-date = 2016-08-06
| archive-url = https://web.archive.org/web/20160806070203/https://tools.ietf.org/id/draft-shalunov-ledbat-congestion-00.txt
| dead-url = no
}}</ref>
但µTP具体的实现方法有别于这些草案。<ref>{{Cite web |url=http://forum.bittorrent.org/viewtopic.php?pid=753#p753 |title=存档副本 |accessdate=2010-02-14 |archive-date=2011-07-25 |archive-url=https://web.archive.org/web/20110725080523/http://forum.bittorrent.org/viewtopic.php?pid=753#p753 |dead-url=no }}</ref>

==相關條目==
* [[µTorrent]]
* [[BitTorrent (协议)|BitTorrent]]
* [[TCP拥塞控制|TCP拥塞控制算法]]

==参考文献==
{{Reflist}}

==外部链接==
* [http://bittorrent.org/beps/bep_0029.html BitTorrent Enhancement Proposal 29] {{Wayback|url=http://bittorrent.org/beps/bep_0029.html |date=20110812124233 }} - µTorrent transport protocol

{{BitTorrent}}

[[Category:BitTorrent]]

Micro Transport Protocol - 版本历史

imported>InternetArchiveBot：​补救19个来源，并将0个来源标记为失效。) #IABot (v2.0.8

imported>InternetArchiveBot：补救19个来源，并将0个来源标记为失效。) #IABot (v2.0.8