[61545] in North American Network Operators' Group
Re: dry pair
daemon@ATHENA.MIT.EDU (Ian Mason)
Fri Aug 29 20:09:23 2003
Date: Sat, 30 Aug 2003 00:43:37 +0100
To: Joel Jaeggli <joelja@darkwing.uoregon.edu>,
Patrick Felt <pfelt@quintam.com>
From: Ian Mason <nanog@ian.co.uk>
Cc: nanog@merit.edu
In-Reply-To: <Pine.LNX.4.44.0308291439260.18203-100000@twin.uoregon.edu>
Errors-To: owner-nanog-outgoing@merit.edu
At 23:03 29/08/2003, Joel Jaeggli wrote:
>On Fri, 29 Aug 2003, Patrick Felt wrote:
[snip]
> > If not,
> > how would the alarm company get the signal pushed through the fiber, and
> > could that be done with the dsl signal?
>
>The alarm companies need to deliver extremely small amounts of data which
>can range from make or break circuits to 60 300 or 2400bps data for things
>like building control systems, that's a considerably different problem
>than try to ram 1-7mb/s through a 25,000 foot long piece of wire.
Not necessarily, the bit rate may be higher. Good modern alarms use a
cryptographically secured bitstream to provide the anti-tamper part of the
line protection. A cryptographically useful message size with a reasonably
short delay between 'raise alarm' and 'indicate alarm' requires a fair bit
rate.
