On Sun, 24 Dec 2006, Roland Dobbins wrote:
What I'm wondering is, do broadband SPs believe that this kind of system will become common enough to make a signficant difference in traffic paterns, and if so, how do they believe it will affect their access infrastructures in terms of capacity, given the typical asymmetries seen in upstream vs. downstream capacity in many broadband access networks? If a user isn't doing
Experiences from high-upstream bandwidth ISPs are that if you give customers high upstream bw, they'll use it. One example is one town, half of the customers were on ADSL (8/1 and 24/1 megabit/s) and half were on 10/10 ethernet (in-building CAT5 or fiber converters). Downstream usage of these two populations were equal, with approx 100 kilobit/s average peak usage. The upstream bw usage was approx 50 kilobit/s for the ADSL crowd, but 200 kilobit/s for the ethernet crowd. This is roughly the figures I have heard from others as well. This is largely from filesharing, and the difference in usage within the population is enormous. Some will average 5-10 kilobit/s over a month, if even that, some will run their upstreams full pretty much 100% of the time. Customers expect unmetered usage but most ISPs have "normal use" clauses in their AUPs. If customers change their behaviour then I believe that ISPs will start to enforce this towards their biggest bw using users, just to try to prolong the usage of their existing investment (or actually their new investment). For me this is actually a core problem, not an access problem. The core is getting faster (4x) every 4-5 years or so, but the traffic is increasing faster than that. Also cost for the core isn't really going down in any major fashion, and it can be cheaper per megabit to build a 10G core than to build a core capable of 100G (parallell links) with todays technology. So to sum up, the upstream problem you're talking about is already here, it's just that instead of using your own PVR box and then sharing that, someone did this somewhere in the world, encoded it into Xvid and then it is shared between end users (illegally). I believe the problem is the same. Also, trying to limit peoples traffic on L4 information or up is futile and won't work. The only information readily available to us ISPs to do anything with, is L3 information and packet size. So in the future I see AUPs that limit traffic to 100-200G per month actually being enforced, because this will cap the powerusers without affecting most of the major population. -- Mikael Abrahamsson email: swmike@swm.pp.se