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Subject: Re: ADSL Bandwidth Monitoring
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On Sat, 8 Sep 2007 23:16:35 -0700
"Ted Mittelstaedt" <tedm@toybox.placo.com> wrote:

> ...
> However, the thing that most people (who don't work at telcos) do not
> understand is that the telcos found very quickly that they cannot put
> contention into an ATM network comprised of a DSL atm circuits for a
> very simple reason.
> 
> ...
> SO, the cost of discarding a single 56 byte ATM cell means the ATM
> cloud will have to get another 1400 bytes of data retransmitted
> through it.
> 
> It doesen't take a rocket scientist to see that introducing contention
> into an ATM circuit carrying a DSL circuit will cause a massive
> increase in traffic in the switch, and wipe out any gains from
> contention. 



I don't know much about DSLAMS, but ATM switches have been able to drop
whole AAL5 frames for a long time. Do DSLAMS really not have EPD/PPD? 

However the contention is done, it definitely happens in the UK.