|
|
Acceleration software for satellite links
This page dates from 2008 and is retained here for historical interest only.
It was review of the software that was used on some satellite internet access services.
In order to make the more efficient use of the satellite capacity it is possible to add software to the end-user customer PCs which will compress text and images both in the transmit and receive directions. There is a corresponding hardware server at the VSAT hub that does the matching process at the hub and thus achieves efficiency savings in both directions.
The acceleration software is particularly suitable for high cost satellite links but could also be of great value in restricted capacity wireless networks, with GPRS and dial-up connections.
Accelerated web browsing
I used Windows XP-SP2 Home edition and IE6. The image compression could be set to Perfect, Excellent, Good or Fair.
| Type of activity. | File name. upload bytes before compression, upload bytes after, download bytes before, download bytes after | Upload compression ratio. | Download compression ratio. |
|
Web browsing Image quality=Perfect |
hughes .jpg image 344 46 2258404 22586921 | 7.48:1 | 1.00:1 |
|
Web browsing Image quality=Excellent |
satsig home page 3537 1988 100662 53755 ivsat.htm 570 268 211834 94354 ivsat-europe.htm 1104 252 140933 69848 testpage.htm 4546872 226980 hughes .jpg image 344 61 2258404 110674 hughes .jpg image 410 64 2258404 110530 |
1.8:1 2.1:1 4.4:1 5.64:1 6.4:1 |
1.9:1 2.1:1 2:1 20:1 20.4:1 20:1 |
|
Web browsing Image quality=Good |
hughes .jpg image 344 61 2258404 52391 satsig forum 20 pages 4610 558 91488 13070 satsig forum tooway 8500 842 147779 34623 |
5.64:1 8.26:1 10:1 |
43:1 7:1 4.3:1 |
|
Web browsing Image quality=Fair |
satsig home page 9965 1897 130525 41849 ivsat.htm 7900 1161 219215 28489 ivsat-europe.htm 2959 445 195206 38354 testpage.htm 4595957 63715 hughes .jpg image 2258404 32014 .jpg image 603 61 2258404 32014 |
5.2:1 6.8:1 5.1:1 9.89:1 |
3.1:1 7.7:1 6.6:1 71:1 70.54:1 70.54:1 |
| FTP file transfers |
download text log file 1 4864107 275172 17:1 download text log file 2 7895841 429796 18:1 download text log file 3 1184405 71213 17:1 download text log file 4 4462002 232724 19:1 uploads text log file 1184332 97150 12:1 large image 2258280 2260783 1.00:1 text log file 34 79 4462002 232724 large image 54 103 2258289 2260783 |
1.00:1 0.43:1 0.47:1 |
17:1 18:1 17:1 19:1 12:1 19:17:1 1.00:1 |
| Email with image | 2780303 499710 5.57:1 | 5:57:1 | |
| Speed tester |
upload 1814 777 769 kbit/s (my nominal max speed 128k) download 164221 3464 6.15 Mbit/s (my nominal max speed 512k) |
2.33:1 |
47.39:1 |
| youTube video/audio | no compression | 1:1 |
Acceleration of web browsing
Browsing from one site to another, looking in search engines and downloading web pages is speeded up by a factor of several times and the improvement in speed is remarkable, with the default setting of 'good' image quality. Even if you select excellent, the speed up is in the order of 2 times faster.
The amount of compression that is possible on images seems to depend to some extent on the original image quality. If the original image lacks detail, for example with large areas of blue sky, then very substantial compression occurs. The best was around 70 times faster, but this was an exception, a large 2 Mbyte image unprocessed direct from a camera.
When browsing the web in 'fair' image mode the pages do download very quickly but the image compression is always noticeable as an image degradation. Initially it comes as a surprise to see company logos blurred a bit. It is also strange how different parts of the image seem to have different quality. It is not smooth blurring all over but blotchy with parts of the image blurred and other areas reasonably sharp. If you want to see the full quality image you can do "right mouse click" and "View original image" which is neat trick to know.
Conclusion: For web browsing I suggest having the image quality set to the default of Good or Fair. On those occasions when you need to download a high quality images, such as viewing a photographers site, I suggest you select Perfect or Excellent. Choosing excellent quality does indeed result in an excellent picture, while still achieving substantial compression.
Acceleration and compression of FTP transfers
I download about 15 to 40 Mbytes of text log files from my server to my home PC each day. This represents a significant load on a satellite downlink which may have a restriction on the amount of Mbytes downloaded each day. The Turbo acceleration software gave a dramatic improvement in speed with compression in the order of 17:1 This was consistent from day to day and really pleasing. The final file as recreated at my end was exactly the same as what was originally on the server, which is what I need for all file transfers, text, html code, software code, binary files, .jpg and .gif images etc. All were transferred reliable with no loss or corruption. It is important to note that there was no compression at all for binary files, .jpg and .gif images.
Acceleration of software package downloads
I tried downloading a software package (wireshark 21 Mbytes) and there was no compression.
Acceleration of emails
I tried sending and receiving an email with a large 2 Mbyte image and the image was compressed by 5.57:1
The image quality was excellent, with detectable but negligible degradation. Regardless of the image quality selected perfect, excellent, good or fair the result was the same. The option to vary the quality relates just to images in web pages. If you want to send an email image without any changes being made to it and without compression you just need to turn the compression off while you send the email.
Acceleration software download
In order to get the system to work you need to download the program to run on your PC. I was given the url to download the software in an email. I am always a bit wary of downloading software but I was assured that the source was reputable so I had a go. All was well and my PC continued working fine, even after upgrading to the latest version which is compatible with Vista.
| >
Page started 1 June 2008, amended 5 April 2021 |