Question : slow browsing while fast file download on satellite Internet link

Hello,

I have 2-way satellite broadband internet link using iDirect satellite modem (Please note that using 2-way satellite internet is subject to latency of min 600 ms to the 1st hop). When I download a file from HTTP, I got fast downloading rate like 400 kbps and same as when uploading a file to HTTP web page.

The problem is on browsing web pages. Once a web page called through a browser, the page download part of its content and then hold up waiting the other parts. Such waiting may exceed the time up setting of the browser and hence the browser give up while the page has half contents. To solve this issue, I have to force reloading/refreshing the page about 3-5 times.
This happen on all web pages even those that are famous like Google, Yahoo, MSN, Experts-Exchange ...etc. I'm tried most popular web browsers like Firefox, IE8, Chrome and Flock all latest versions but with no help!

It seems to me that on multiple TCP sessions towards HTTP resources get some to be broken during downloading them. While on a single download TCP session, the session get fast downloading speed.

What kind of web accelerators do you suggest that internally designed for satellite links having high latency? Perhaps using TCP optimization for satellite links is a necessity?

I'm using Vista 32-OS in case  you would like to suggest an optimization tool or web accelerator tool.

Thank you in advance ...

Answer : slow browsing while fast file download on satellite Internet link

According to that recommendation, changing the unscaled RWIN to 64240 on that XP machine should help.
The vista machine should tweak (autotune) that value itself.

Rather than manually editing the registry, a tool (SG TCP Optimizer) to easily tweak that is located at the top of speedguide's download page
http://www.speedguide.net/downloads.php

Caveats
No installation is required; you can run it from wherever you save it, and windows may prompt asking if you're sure you want to allow that program to run.
Be sure to select the proper network adapter from the picklist near the center of the General Settings tab.
Backup the settings before you start tweaking using File->Backup current settings, so if you tweak too much and actually make things worse you can always go back to what you started with (using File->Restore backed up settings).
Don't make wholesale changes all at once. Change 1 setting (not radically), save it, reboot (nearly all its tweaks require rebooting for the changes to be implemented) and rerun the speed tests at those same 3 sites to compare with the baselines shown in http:#a24843432 's attachments.


Tweak
After backing up your current settings on the network adapter you're using (it's not clear from your posts if you are connecting to the satellite link with cat5 or by wireless card), on the General Settings tab in the TCP Optimizer util,  tick the Custom Settings button at the bottom, and enter 64240 in the TCP Receive Window field (left side, just below the Network Adapter selection box). Click on the Apply changes button, then Exit. Reboot, rerun the speed test at the same 3 sites.

That single tweak might make quite a difference, and it's the only one recommended by the analyzer page, really.
Checking the Windows Scaling box in the TCP 1323 Options box (lower-right corner) should not be necessary unless you want to try window sizes above 64KB (65535), but it's not a cinch that 128480 would improve your speeds any more than 64240 does.

Please let us know what results you get.