>From: "David Mill" <maildave@inspire.net.nz>
>To: <adsl@lists.unixathome.org>
>Subject: RE: ADSL, who pays?
>Date: Fri, 17 Oct 2003 17:47:03 +1300
>
>Its all quite simple, but right about now its Friday evening so Im off to
>the pub.

Indeed it is quite simple. Others have hinted at this - but I'll just be
clear.

There are two differnt products - jetstream and jetstart. Jetstream, telecom
(well except a couple of isp's - if there are still any that do) provide the
bandwidth - so it is simply routed to global gateway/the internet. For
jetstart the data flows from ipnet to your isp then to the internet.

Its fairly obvious that its a good idea to do accounting at the earliest
possible opertunity. In the case of jetstream that happens to be the DSLAM's
(Digital subscriber line access multiplexor) or whatever the new buzword
names they give the new alcatel units are (the brain fails me at 10pm on a
friday night). Which is quite simply the device you connect to at the
exchange.

For Jetstart - your isp can't start counting data until it has flowed to it
- so it occurs a bit further down the line.

So Jetstream is accounted based on the line (the actual physical port -
sorta) that you connect to the exchange with. Hence if you use sombody
else's jet*stream* login it will be charged against you. I even vaugely
remember a conversation from a few years back about the DSLAMS counting data
at layer2 - meaning it also counts the atm frames or cells (whatever the
layer 2 encoding for PPP over ATM is - read up on the OSI model if you have
no idea what I'm talking about). Although I don't remember the outcome of
that conversation - if anybody can remember I'm interested to know.

However - with jet*start* the accounting is based on data flowing through
your isp with a particular ip address - so you can use your login when
staying at your mate's place and have it charged to your account.

So there is one of two possible outcomes when a user becomes uncaped.
1) One or more radius servers stuffed up along the way and it now thinks you
have a jetstream line and routes the data through telecom - but telecom
doesn't keep your accounting info because you shouldn't have a jetstream
line - so no data flows through your isp and telecom isn't counting.
Wooohooo to anybody this happens to ;) (jk guys).

2) The 128K ratelimiting at your exchange decides to lose it's mind. So data
is still flowing to your isp, and I suppose isp's don't do their own
ratelimiting on the incomming data, because its theoretically completely
unnessasary (the data should already be ratelimited) and very heavy on
router 'horsepower'. In this situation you would be getting a semi-unlimited
speed (depending how good your isp is :P) but it would still be flowing
through your isp - so adding to your bill.

There - clear as mud? Please feel free to correct me - I'm not exactly
completely up to speed on nz ISP best practises - but I think thats the guts
of it.

Also a thing to note is that when a jetstart line is first
installed/enabled/whatever apparently it is full speed jetstream until the
next / 2nd time you login. I've heard of people keeping their linux routers
up for a while to take advantage of this :).

These are only my views rah rah rah....

--
Disclaimer: This e-mail contains the offical views of the voices in my head.
-m
>
>I'll explain it in full when I get back if someone hasn't already.... 
>Unless
>Ive had a few too many beers :)
>
>Dave
>
>-----Original Message-----
_________________________________________________________________
Gaming galore at  http://xtramsn.co.nz/gaming !
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