[95515] in North American Network Operators' Group
Re: TCP and WAN issue
daemon@ATHENA.MIT.EDU (Robert Boyle)
Thu Mar 29 00:44:27 2007
Date: Thu, 29 Mar 2007 00:43:35 -0400
To: nanog@merit.edu
From: Robert Boyle <robert@tellurian.com>
Errors-To: owner-nanog@merit.edu
A lot of different theoretical things have been discussed, but
basically, if you are running Windows XP, 2000, or 2003 over a WAN
with anything more than 10-20ms of latency, make the following change
to the registry and you will find a world of difference. Ideally, you
would make the change to both sides, but as long as one side has
this, it will auto-negotiate with the other side to adjust the
Start, Run, regedt32
Go to:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters
Edit, New -> DWORD Value
Then name it "Tcp1323Opts" (without the quotes) and change the value to 3
That will give you far better performance by enabling automatic TCP
window size scaling as per RFC 1323 over your WAN links (hence the
key name), but only to other computers which support RFC1323. XP and
2003 default to allowing scalable windows if the far side intiates
the negotiation, but that will never happen unless one side has this key set.
Values are:
0 (disable RFC 1323 options) - default before creating the key
1 (window scale enabled only)
2 (timestamps enabled only)
3 (both options enabled)
Try this and let us know what you see.
-Robert
Tellurian Networks - Global Hosting Solutions Since 1995
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