LinuxSA Mailing list archives

  From: Alan Kennington <akenning@topology.org>
  To  : LinuxSA <linuxsa@linuxsa.org.au>
  Date: Sun, 10 Jun 2001 16:00:38 +0930

Re: [OT] Telstra ADSL 'Unlimited' Introduces Download Limit

On Sun, Jun 10, 2001 at 03:30:36PM +0930, David Lloyd wrote:
> 
> 
[....]
> Besides, putting it particularly bluntly, a user not downloading pirated
> music via some napster like service may not be likely to exceed 3Gb of
> data download during the month.
> 

Netizens,

Not that I want to perpetuate this thread or anything, but...

I've heard that a typical ADSL access network in the USA
sticks 100 users on a single T1 (1.5 Mbit/sec) to the core network.
That's about 15 kbits/sec each, averaged over a day.

Now 1 kbit/sec = 10 MByte/day (give or take an overhead here or there).
So 15 kbit/sec = 150 MByte/sec.

Since most people are not using the link 24 hours a day,
and therefore there will be some slack in the link for many
hours per day, this means that you would be unlikely to
expect even 100 MBytes/sec on the standard north american
"unlimited account".

I've heard that any more generous allowance of bandwidth to subscribers
makes an ADSL business uneconomic.
When you stick in all the reasonable numbers for operating costs
and subscriber rental etc., it turns out that a typical ADSL access provider
is paying 30% of their costs for the core internet link (that T1 link).
So increasing the bandwidth to two T1 links is going to make the
economics of it look bad.

It seems to me like the Telstra way of doing things _may_ be to provide
more upstream bandwidth for the subscribers - but to use service level clauses
and pricing to limit usage.

In this case, the perceived congestion is therefore perceived to be
less than it would be in a typical 100-subscriber-per-T1 US network,
and SLA clauses are used instead of traffic congestion as a way
of moderating user bandwidth.

So I think that the ADSL deal sounds fine.
Yes, there's the issue of changing the conditions, but apart from that,
it's still not a bad deal.

I've received some advertising last week for ADSL in my area (Prospect),
and it claims total cost of ADSL for 12 months is around $1200.
(There's no mention at all of "unlimited" in the glossy brochure, by the way.)

I currently download 200 MB/month (7 MByte/day, 0.7 kbits/sec) and upload
1200 MB/month (40 MByte/day, 4 kbits/sec) over my 33 kbit/sec modem link.
Clearly on _average_, my 33k link is way too fast!
But for this, I pay around $1200 per year, ignoring the one-off
starting cost and the extra phone line.
With the phone line and one-off costs, this becomes over $2000 in the first year.


So it looks to me like the ADSL deal gives the subscriber a much better deal
than my current very reasonable deal.

Maybe as the ADSL subscribership increases, the ADSL users _will_ be
connected to limited bandwidth as in the USA.
And then the SLA clauses will seem very generous, because you'll be
struggling to get that 100 MBytes/day because of chronic congestion!!!

Just my US$0.01 worth.

Cheers,
Alan Kennington.

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