[tahoe-dev] uTP (low extra delay transport)

[Jeremy Fitzhardinge]

On 05/22/2010 10:37 PM, ghazel at gmail.com wrote:
> BitTorrent, Inc. has recently released uTP (uTorrent Transport
> Protocol) under the MIT license. uTP is a TCP-like implementation on
> UDP, made to use the LEDBAT (Low Extra Delay Background Transport)
> congestion controller. The library is C/C++, but I have wrapped it up
> with ctypes for use in Python.
>   

Useful!

> You can read more about the congestion controller and its rational here:
> http://datatracker.ietf.org/wg/ledbat/charter/
>
> Setting aside the ease of hole-punching with UDP,

Is hole punching that much easier with UDP?  Does it help with the
problem of getting in touch with a server behind a NAT gateway?

> I can understand use-cases for Tahoe which might benefit from
> aggressive, TCP-like behavior. Primarily, trying to stream video
> should probably compete with other TCP connections. However,
> non-interactive replication to shares seems like an opportunity to use
> uTP, if congestion caused by uploading might be a burden on the
> network.
>
> So my question is; would the Tahoe project be interested in integrating uTP?
>   

There have been some discussions about moving Tahoe to an HTTP-based
protocol, partly to make it easier to create a python-independent
protocol specification and take advantage of all the infrastructure HTTP
enjoys (from network support to programming environments).

uTP does seem to have some interesting properties, but it does pose make
a library implementation a prerequisite for any Tahoe implementation.

    J