LinuxSA Mailing list archives

  From: Mark Newton <newton@atdot.dotat.org>
  To  : <paul@mawsonlakes.org>
  Date: Wed, 22 Nov 2000 12:22:04 +1030

Re: ADSL Enabled Exchange Areas: Updated 20/11/2000

On Wed, Nov 22, 2000 at 10:22:02AM +1030, Paul Schulz wrote:

 >    So what do you get with an ADSL service? And who supplies it?
 >    From these posts, and from discussions elseware..
 >    - ADSL runs over regular copper pairs, using a separate frequency band
 >      to voice, and requires 'splitters' at each end to mudge the two
 >      signals together, and split them up at the other end. Hence ADSL
 >      requires end to end copper wiring.
 >      (Is this suppied by the telco?)
 
It's more the case that you can't get it unless the telco has already
provided end-to-end copper (i.e.: if your house is "Pairgained", or if
you're on the wrong kind of RIM, or your local loop is something other
than raw copper with no loading coils, you won't be able to get ADSL).

You don't speak to your Telco to organize it, you speak to your ISP.
So if you want to use XYZed, you talk to XYZed (not Telstra). If you
want to use BigPond, you talk to BigPond (not Telstra).  If you want to
use Internode, you talk to Internode (not Telstra).  If you talk to 
Telstra, their response will be, "We don't do ADSL, but I'll transfer
you to someone who does," whereupon you will be talking to a BigPond 
salescritter.

 >    Use either: 
 >    - An "external" ADSL modem, in a box with both an ADSL and 10BaseT(?)
 >      interface.  (Who has experience with one of these? How is the IP
 >      interface configured?)
 
You won't need to buy one of these, it's provided as part of the service.
It has no customer-servicible parts inside, all configuration is performed
by the ISP.  It doesn't have an "IP interface", it has an Ethernet 
interface;  the combination of the ADSL modem and the DSLAM effectively 
forms an Ethernet-to-ATM remote bridge.

 >    - Internal PCI ADSL modem card.  (My best guess so far..) The card
 >      provides a serial connection across the phoneline, over which PPP
 >      can be run, which suppies the IP connectivity, allocating IP
 >      address, DNS settings etc.

No -- The card behaves like an Ethernet card.  You still use PPPoE to use
it (not PPP over serial).

 >      Is the 'splitter' included in the PCI ADSL Card? (Is there a
 >      separate 'phone-out' on the card?)

Depends on the card, but not usually.

 >    Please correct me. What have I missed? What is PPPoE used for?

PPPoE is used so that copper which is plugged into a DSLAM provided by
a phone carrier (e.g.: Telstra) can be used for any of a number of 
different ISPs (e.g.: BigPond, Internode, Optus, whatever).  This allows
ISPs to offer ADSL services in areas where they haven't yet installed
DSLAMs by wholesaling copper from the phone company.  When the ISP 
installs their own DSLAM in future, they continue to use PPPoE so their
customers don't need to change anything.

The PPPoE session is beteween an ISP's router and a customer's workstation.
The ISP can bill for usage on that PPP session just like they would on 
any other PPP-based permanent link they might care to offer.

  - mark

--------------------------------------------------------------------
I tried an internal modem,                    newton@atdot.dotat.org
     but it hurt when I walked.                          Mark Newton
----- Voice: +61-4-1620-2223 ------------- Fax: +61-8-82231777 -----

-- 
LinuxSA WWW: http://www.linuxsa.org.au/  IRC: #linuxsa on irc.linux.org.au
To unsubscribe from the LinuxSA list:
  mail linuxsa-request@linuxsa.org.au with "unsubscribe" as the subject