Micro Transport Protocol

Micro Transport Protocol或稱µTP是一個由 µTorrent完成的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。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, Inc.所開發的，沒有投入更廣泛的網路社群。它首先於µTorrent 1.8.x beta加入，並於µTorrent 1.9 Alpha中正式對外公開。

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。

目前沒有自由軟體完全实现uTP。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。 另一些人提出，尽管TCP协议有许多优点，但由于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。.

運作

µTP由兩個部分所組成: a framing scheme, and a congestion control algorithm that is less aggressive than that of TCP.

µTP framing

µTP stores data within UDP datagrams using its own framing scheme. The framing scheme has functionality roughly equivalent to that of TCP (with timestamps and SACK), but realized in a somewhat idiosyncratic manner.

The µTP framing scheme is believed by some to be far from optimal.

µTP congestion control

The congestion control algorithm used by µTP, known as Ledbat, aims to decrease the latency caused by applications using the protocol while maximizing bandwidth when latency is not excessive. Additionally, information from the µTP congestion controller can be used to choose the transfer rate of TCP connections.

Ledbat has been described in an Internet-Draft, but the details of the µTP implementation are different from those of the draft.

相關條目

• µTorrent
• BitTorrent
• BitTorrent Enhancement Proposal 29 - µTorrent transport protocol
• TCP congestion avoidance algorithm
• TCP-LP