On Sun, 2015-08-30 at 10:29 +1000, Tom Worthington wrote: > Perhaps someone can answer a question about the current NBN "Interim > Satellite Service" (ISS): Why is compression OFF by default? [...] > Why would compression limit the speed of the service? Probably because compression costs CPU. Like any communications device, a satellite is fastest when it can just ship stuff in and out. If it has to process what it ships, it slows down. Also, CPU is energy, and a satellite has limited energy.
As a general rule, compression should only be used where the time taken to compress the data is smaller than the difference between the time taken to send the uncompressed data and the time taken to send the compressed data AND where the cost of compression is lower than the cost of that transmission time difference. I suspect it is the second of those that works against compression in this case. > compression limits the speed in some cases, would customers benefit overall? Dunno. I suspect there would be a "tragedy of the commons" effect if everyone went for compression. Regards, K. -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Karl Auer ([email protected]) http://www.biplane.com.au/kauer http://twitter.com/kauer389 GPG fingerprint: 3C41 82BE A9E7 99A1 B931 5AE7 7638 0147 2C3C 2AC4 Old fingerprint: EC67 61E2 C2F6 EB55 884B E129 072B 0AF0 72AA 9882 _______________________________________________ Link mailing list [email protected] http://mailman.anu.edu.au/mailman/listinfo/link
