slow browsing while fast file download on satellite Internet link


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 ...
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Slow web browsing in Vista is more than likely caused by a 3rd party program scanning the web pages  
one source I found that caused this problem was the program SpySweeper.
If the  Common Ad Sites shield is enabled  web browsing  with Java-heavy websites in Vista will be painfully slow.
Disable Spysweeper if you have it returned the speed.
Another sourced solution for slow web browsing disable this-->
control panel --> Device Manager --> Network Adapters --> Wireless Adapter --> Power Settings and UNCHECKED "Allow the computer to turn off this device to save power .
Hope it assists you
Try 2 or 3 sites at different distances from you on
to get an average baseline speed... say, 1 from the US, 1 from DE, and the 1 in Jakarta, then copy and paste the results (or at least the links to the image showing the up/down speeds) to notepad to save for comparison later.

Then see what the TCP Analyzer says at
Especially note the RWIN value currently set and those recommended, and the calculated maximum speeds possible under the ''bandwidth * delay product'' heading with theoretical ping times.

All the satellite providers I'm aware of will throttle back your bandwidth if you exceed the 'average use' (it's in the fine print of the contract), but it doesn't sound like that is what is happening in your case.
> Especially note the RWIN value currently set and those recommended

I believe vista is supposed to 'autotune' that value for you, but maybe it's not optimized for 44,000+ mile delay times.
MoodynetAuthor Commented:
Dear Merete,

Thanks for your reply. I don't use SpyDoctor or any variant like it, but I use Kaspersky Internet Security (KIS) ver. that use web traffic analysis in a kind that intercept web traffic by local host proxy. However disabling KIS did never solve my issue.
Changing power setting for wireless adaptor is not my case as my PC connected via Ethernet interface.

Dear Darr247,

Per your instructions, I'm attaching in Code Snippet area the following test results:
Speed test from erver in Ca, USA.
Speed test from server in Nietherland
Speed test from server in Jakarta.
TCP/IP analysis
Ping test from my PC to a remote host in US.
Trace route from my PC to a remote host in US.

Please note that my PC now is Win XP 32-bit, but I will do same tests on my Vista PC tomorrow when it get repaired!

Satellite providers use what its called shared link that has bib capacity but shared at least between 20 remotes users and it denoted as contention ratio of 1:20; my link is 1:20 with max download speed of 512 kbps and max upload speed of 128 kbps, but not all 20 remotes are online on same time and thus I can get bandwidth daily not less than what you see in speed test results.

Kindly advice ...

« Speed Test Results »
251 kbps down (~0.25 Mbps, 31 KB/s)“ 
48 kbps up (~0.05 Mbps, 6 KB/s)‘ 
500 KB downloaded in 16.322 seconds 
100 KB uploaded in 17.006 seconds 
Tested on: 2009.07.13 15:17 EDT 
Tested from: 
Test Link: 
« Speed Test Results »
392 kbps down (~0.39 Mbps, 48 KB/s)“ 
52 kbps up (~0.05 Mbps, 6 KB/s)‘ 
500 KB downloaded in 10.458 seconds 
100 KB uploaded in 15.709 seconds 
Tested on: 2009.07.13 15:24 EDT 
Tested from: 
Test Link: 
« Speed Test Results »
316 kbps down (~0.32 Mbps, 39 KB/s)“ 
51 kbps up (~0.05 Mbps, 6 KB/s)‘ 
500 KB downloaded in 12.949 seconds 
100 KB uploaded in 16.047 seconds 
Tested on: 2009.07.13 15:27 EDT 
Tested from: 
Test Link: 
« TCP Analyzer Results » 
Tested on: 07.13.2009 15:32 
IP address: 
Client OS: Windows XP 
TCP options string: 020405b401010101 
MSS: 1460 
MTU: 1500 
TCP Window: 1460 (multiple of MSS) 
RWIN Scaling: 0 bits  
Unscaled RWIN : 1460 
Recommended RWINs: 64240, 128480, 256960, 513920, 1027840 
BDP limit (200ms): 58kbps (7KBytes/s)
BDP limit (500ms): 23kbps (3KBytes/s) 
MTU Discovery: ON 
TTL: 112 
Timestamps: OFF 
IP ToS: 00000000 (0) 
C:\Documents and Settings\Moody>ping -n 50
Pinging with 32 bytes of data:
Reply from bytes=32 time=628ms TTL=243
Reply from bytes=32 time=872ms TTL=243
Reply from bytes=32 time=788ms TTL=243
Reply from bytes=32 time=788ms TTL=243
Reply from bytes=32 time=770ms TTL=243
Reply from bytes=32 time=689ms TTL=243
Reply from bytes=32 time=790ms TTL=243
Reply from bytes=32 time=884ms TTL=243
Reply from bytes=32 time=664ms TTL=243
Reply from bytes=32 time=884ms TTL=243
Reply from bytes=32 time=790ms TTL=243
Reply from bytes=32 time=646ms TTL=243
Reply from bytes=32 time=891ms TTL=243
Reply from bytes=32 time=613ms TTL=243
Reply from bytes=32 time=880ms TTL=243
Reply from bytes=32 time=966ms TTL=243
Reply from bytes=32 time=843ms TTL=243
Reply from bytes=32 time=716ms TTL=243
Reply from bytes=32 time=746ms TTL=243
Reply from bytes=32 time=748ms TTL=243
Reply from bytes=32 time=767ms TTL=243
Reply from bytes=32 time=758ms TTL=243
Reply from bytes=32 time=745ms TTL=243
Reply from bytes=32 time=949ms TTL=243
Reply from bytes=32 time=639ms TTL=243
Reply from bytes=32 time=832ms TTL=243
Reply from bytes=32 time=912ms TTL=243
Reply from bytes=32 time=817ms TTL=243
Reply from bytes=32 time=748ms TTL=243
Reply from bytes=32 time=773ms TTL=243
Reply from bytes=32 time=729ms TTL=243
Reply from bytes=32 time=940ms TTL=243
Reply from bytes=32 time=640ms TTL=243
Reply from bytes=32 time=951ms TTL=243
Reply from bytes=32 time=702ms TTL=243
Reply from bytes=32 time=709ms TTL=243
Reply from bytes=32 time=744ms TTL=243
Reply from bytes=32 time=581ms TTL=243
Reply from bytes=32 time=889ms TTL=243
Reply from bytes=32 time=902ms TTL=243
Reply from bytes=32 time=639ms TTL=243
Reply from bytes=32 time=779ms TTL=243
Reply from bytes=32 time=866ms TTL=243
Reply from bytes=32 time=762ms TTL=243
Reply from bytes=32 time=813ms TTL=243
Reply from bytes=32 time=813ms TTL=243
Reply from bytes=32 time=870ms TTL=243
Reply from bytes=32 time=977ms TTL=243
Reply from bytes=32 time=622ms TTL=243
Reply from bytes=32 time=873ms TTL=243
Ping statistics for
    Packets: Sent = 50, Received = 50, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 581ms, Maximum = 977ms, Average = 786ms
C:\Documents and Settings\Moody>tracert -d
Tracing route to over a maximum of 30 hops
  1     2 ms     2 ms     2 ms
  2     3 ms     3 ms     7 ms
  3   793 ms   800 ms   825 ms
  4   736 ms   600 ms   671 ms
  5   868 ms   738 ms   635 ms
  6   861 ms   731 ms   764 ms
  7   866 ms   901 ms   889 ms
  8   686 ms   895 ms   902 ms
  9   705 ms   903 ms   892 ms
 10   987 ms   706 ms   666 ms
 11   721 ms   637 ms   810 ms
 12  1021 ms   586 ms   640 ms
 13   728 ms   734 ms     *
 14   864 ms   893 ms   669 ms
 15   802 ms   788 ms   901 ms
 16   771 ms   826 ms   794 ms
 17   897 ms   896 ms   890 ms
 18   903 ms   895 ms   898 ms
 19   700 ms   795 ms   692 ms
 20   899 ms   802 ms   901 ms
Trace complete.
C:\Documents and Settings\Moody>

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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

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.

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.

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