[clue-tech] Qwest DSL download speed reduced

[black at clapthreetimes.com]

> On Fri, 26 May 2006, Jed S. Baer wrote:

> I believe PPPoA is "PPP over ATM", but I'm not sure.  My guess is that
> the DSL protocol ('CAP' and 'DMT' were competing on-the-wire protocols
> in the 1997-2000 time frame, analogous to the electrical specs and
> Manchester
> encoding specified by Ethernet) carries the ATM frames, so that the
> kind of firewall box I want to build has to deal with PPP-over-ATM
> (PPPoA),
> but there's an outside possibility that the CAP or DMT layer carries
> ethernet frames, rather than ATM cells.

Yes, PPPoA is PPP over ATM, similar in the same way that PPPoE is PPP over
Ethernet.

CAP and DMT have to do with how the physical line is used to carry data,
it's the signaling. With CAP, I believe there is just one "channel" that
all data moves across. With DMT there are multiple channels with smaller
capacities. DMT is the new way of seeing and believing.