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Re: TCP and WAN issue

  • From: Steve Meuse
  • Date: Tue Mar 27 21:44:00 2007
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On 3/27/07, Lincoln Dale <[email protected]> wrote:

even on "default settings" on a modern TCP stack, getting close to
path-line-rate on a 80msec RTT WAN @ DS3 speeds with a single TCP stream should
not be that difficult.

the Windows TCP stack as of Windows XP SP2 has some fairly decent defaults.  it
will do RFC1323 / large windows / SACK., but all of these can be tuned with
registry settings if you wish.

I was under the impression that XP's default window size was 17,520 bytes, rfc1323 options disabled.

Assuming 80ms and 45Mb/s, I come up with a window size of 440Kbytes required to fill the pipe. At windows default I would only expect to see 220Kbs over that same path.

I think even modern *nix OSs tend to have default window sizes in the 64kB region, still not enough for that Bandwidth/delay.