Home media servers, AUPs, and upstream bandwidth utilization.

Mikael Abrahamsson swmike at swm.pp.se
Mon Dec 25 07:29:32 UTC 2006

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 

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 

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 

Mikael Abrahamsson    email: swmike at swm.pp.se

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