On Fri, 27 Feb 2015 23:24:17 +0000, "Naslund, Steve" <SNaslund@medline.com> said: > I was an ISP in the 1990s and our first DSL offerings were SDSL > symmetric services to replace more expensive T-1 circuits. When > we got into residential it was with SDSL and then the consumers > wanted more downstream so ADSL was invented. I was there, I > know this. So was I and my experience was different. We decided that it would be more profitable as a small ISP to re-sell Bell Canada's ADSL than to try to unbundle central offices all over the place. The arguments from the business side had nothing whatsoever to do with symmetry or lack thereof. The choice of technology was entirely by the ILEC. > To that I will just say that if your average user spend as much > time videoconferencing as they do watching streaming media then > they are probably a business. No, you misunderstand. I don't dispute that the area under end-user traffic statistics graphs is asymmetric. But that the maximum value -- particularly the instantaneous maximum value which you don't see with five minute sampling -- wants to be quite a lot higher than it can be with a very asymmetric circuit. If someone works from home one day a week and has a videoconference or too, we still want that to work well, right? And perfect symmetry is not necessary. Would I notice the difference between 60/60 and 60/40 or even 60/20? Probably not really as long as both numbers are significantly more than the expected peak rate. But 24/1.5, a factor of 16, is a very different story. -w -- William Waites <wwaites@tardis.ed.ac.uk> | School of Informatics http://tardis.ed.ac.uk/~wwaites/ | University of Edinburgh The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.