TCP Optimizer "RWIN is not fully optimized" How do I correct this?

[bydnas]

Hi. This is my first post on this forum so hi to everyone & hope you can help.

I ran the SG TCP Optimizer, set connection speed slider to 8.5Mbs (max in my area is 8.1Mbs) & checked "modify all network adapters". Selected "optimal" then apply changes.
After restart I ran the SG TCP/IP Analyzer. I'm not great tech head but everything looked ok to the best of my knowlege appart from a message in red text saying "RWIN is not fully optimized. The unscaled RWIN value is lower than it should be. Also, RWIN being close to and above 65535 does not justify the header overhead of enabling TCP 1323 Options. You might want to use one of the recommended RWIN values below".

The "values below" are:
RWIN is a multiple of MSS
Other RWIN values that might work well with your current MTU/MSS:
64240 (up to 2 Mbit lines, depending on latency. MSS * 44)
128480 (1-5 Mbit lines, depending on latency. MSS * 44 * 2)
256960 (2-14 Mbit lines, depending on latency. MSS * 44 * 2^2)
513920 (8-30 Mbit lines, depending on latency. MSS * 44 * 2^3)
1027840 (25-60 Mbit lines depending on latency. MSS * 44 * 2^4)

What do I need to do to get the correct values? I've posted my results below.

I'm in Scotland UK. I read your location has something to do with this?

Many thanks, Sandy.


« SpeedGuide.net TCP Analyzer Results »
Tested on: 2012.05.24 13:22
IP address: 81.155.xxx.xxx
Client OS/browser: Windows 7 (Internet Explorer 9.0)

TCP options string: 020405b40103030201010402
MSS: 1460
MTU: 1500
TCP Window: 65700 (multiple of MSS)
RWIN Scaling: 2 bits (2^2=4)
Unscaled RWIN : 16425
Recommended RWINs: 64240, 128480, 256960, 513920, 1027840
BDP limit (200ms): 2628kbps (329KBytes/s)
BDP limit (500ms): 1051kbps (131KBytes/s)
MTU Discovery: ON
TTL: 46
Timestamps: OFF
SACKs: ON
IP ToS: 00000000 (0)

[Philip]

Windows 7 auto-tunes the RWIN value on the fly, depending on line condition. As a user you can't direcly edit it to a fixed value, you can only change the behavior of the auto-tuning algorithm somewhat (the TCP Optimizer allows for that).

[bydnas]

Thanks for your quick reply.

Many thanks, Sandy.