Best utilizing fat long pipes and large file transfer

Date: Fri, 13 Jun 2008 12:40:48 -0400
From: Robert Boyle <>

>Clearly you have failed to try very hard or to check into what others
>have done. We routinely move data at MUCH higher rates over TCP at
>latencies over 50 ms. one way (>100 ms. RTT). We find it fairly easy to
>move data at over 4 Gbps continuously.

That's impressive.

>If you can't fill a GE to 80% (800 Mbps) at 30 ms, you really are not
>tying very hard. Note: I am talking about a single TCP stream running
>for over 5 minutes at a time on tuned systems. Tuning for most modern
>network stacks is pretty trivial. Some older stacks (e.g. FreeBSD V6)
>are hopeless. I can't speak to how Windows does as I make no use of it
>for high-speed bulk transfers.

Let me refine my post then...
In our experience, you can't get to line speed with over 20-30ms of
latency using TCP on _Windows_ regardless of how much you tweak
it. >99% of the servers in our facilities are Windows based. I should
have been more specific.

Sorry, but I don't do Windows, but my friends who do claim that this is
not true.