[105119] in North American Network Operators' Group
Re: Best utilizing fat long pipes and large file transfer
daemon@ATHENA.MIT.EDU (Robert Boyle)
Thu Jun 12 19:27:37 2008
Date: Thu, 12 Jun 2008 19:26:56 -0400
To: Sean Knox <sean@craigslist.org>
From: Robert Boyle <robert@tellurian.com>
In-Reply-To: <4851A53B.4010400@craigslist.org>
Cc: nanog@merit.edu
Errors-To: nanog-bounces@nanog.org
At 06:37 PM 6/12/2008, you wrote:
>I'm looking for input on the best practices for sending large files
>over a long fat pipe between facilities (gigabit private circuit, ~20ms RTT).
>I'd like to avoid modifying TCP windows and options on end hosts
>where possible (I have a lot of them). I've seen products that work
>as "transfer stations" using "reliable UDP" to get around the
>windowing problem.
>
>I'm thinking of setting up servers with optimized TCP settings to
>push big files around data centers but I'm curious to know how
>others deal with LFN+large transfers.
In our experience, you can't get to line speed with over 20-30ms of
latency using TCP regardless of how much you tweak it. We transfer
files across the US with 60-70ms at line speeds with UDP based file
transfer programs. There are a number of open source projects out
there designed for this purpose.
-Robert
Tellurian Networks - Global Hosting Solutions Since 1995
http://www.tellurian.com | 888-TELLURIAN | 973-300-9211
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