From: DaZZa [mailto:[EMAIL PROTECTED]]
> On Tue, 8 Aug 2000, James Wilkinson wrote:
>
> > > Cable connections will now have max bandwidth of 256k
> rather than 400k.
> >
> > Apologies to everyone who's explained why O@H is no good
> for them but:
> > why would you bother at all with telescum? I mean... optus cable is
> > download capped at 3Mbit, like almost 10 times that of BPA cable and
> > ADSL. For roughly the same price.
>
> Sure - 2 meg - SHARED_ access - and if you have, say, 20
> people on each
> cable segment - that 2 meg disappears pretty quickly.
This is based on the somewhat false assumption that all people are using
their full bandwidth all of the time. Given that the average ISP has at
least 10 users per modem and at least 10 times the number of modems that
their external bandwidth can handle I think 20 people sharing a cable
segment (which can handle 33Mb) is a pretty fair amount. If it got up to
about 100 I'd start to get a little worried.
> > ADSL can in theory do 8Mbit. I can't back this up, I heard from a
> > friend, but if that's true, then why are Smellstra so keen to limit
> > everyone's access? Can't their infrastructure cope with such a high
> > bandwidth? What kind of service do they think people will pay for?
>
> The difference between ADSL and HFC systems is that HFC system uses a
> _shared_ carrier - it's more of a broadcast system - and ADSL is a
> _direct_ connection - you get your 1.5 meg ALL the time - not
> just when
> none of your neighbours are using the net as well as you.
Except for the fact that all ADSL lines still come into an exchange and you
get a shared medium there. If you are lucky then they have the bandwidth
from the exchange to support the number of ADSL users they plug in. You
have to assume they are running better than 100Mbps equipment in the
exchange before they can exceed the capacity of HFC systems. The idea that
ADSL gives you the bandwidth to yourself and cable doesn't is such a mind
boggling oversimplification it's almost a delusion.
Having been connected to BPA (cable) for a while now, I can say that the
real bandwidth problems have been with the Big Pond Direct connection from
Perth to the USA and never with the saturation of the local loop.
Occasionally there are problems with the local servers or with routing but
I've never gotten less than my capped speed between my machine and the local
router.
John Wiltshire
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