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。

目前沒有自由軟體加入uTP。Some, in the Free Software community, believe that the goals of µTP are better met by adding µTP's congestion control to TCP rather than by designing an application-specific framing scheme. Others note that TCP, for all its advantages, is very slow to expose new functionality to applications due to its tight integration with operating system kernels.

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