Begin forwarded message:
From: Armando Stettner <[EMAIL PROTECTED]>
Date: August 12, 2006 3:19:11 PM EDT
To: [EMAIL PROTECTED]
Cc: [email protected]
Subject: Re: [IP] Your Cable Company -- powered by the guy with the
extension cord
Dave,
For IP'ers if you wish.
The situation that Lauren came across is most unusual. Most cable
companies, bowing to competitive and/or local PUC regulatory
pressures, provide both battery backup and generators throughout
their infrastructure - even out at some remote polls. Still, the
subscribers' must have their VoIP cable modem powered.
One of the more important differences between phone services from
traditional telephone company vs. those from a cable company is how
power is distributed. The traditional phone company powers your
plain old home phone (not wireless, etc.) from the wire (pairs)
themselves. Cable companies do not typically provide power down to
the subscriber (although devices along trunk and feeders in the cable
plant can be powered by in-line power devices).
So, if one has phone service from a cable company, your cable modem
has to be powered for your phone service to work. Many cable
companies recognize this problem and supply cable modems supporting
VoIP that include a small UPS. Others actually power the VoIP cable
modem (sometimes called an network interface unit or multimedia
terminal adaptor) from 'cable' power using drop cable with additional
conductors to carry the power. It should be noted that the cable
company's VoIP is somewhat different from those of Vonage and
similar providers, etc. Vonage and others support SIP and are not
associated with the subscriber's broadband supplier (cable company or
telephone company's DSL). The cable company's VoIP is usually based
on CableLabs' PacketCable. (Vonage, and I assume others, have neat
feature where when the subscribers network device is not accessible,
they will ring a designated phone number such as a cell phone, etc.)
As an aside, when I was involved with engineering VoIP for cable
systems and advanced cable set top boxes, one commonly held belief/
statistic is that about 50% of US households had only wireless/
cordless phone instruments and, as such, were mostly out of luck when
the electric service was out.
armando
Begin forwarded message:
From: David Farber <[EMAIL PROTECTED]>
Date: August 12, 2006 11:31:01 AM PDT
To: [email protected]
Subject: [IP] Your Cable Company -- powered by the guy with the
extension cord
Reply-To: [EMAIL PROTECTED]
Begin forwarded message:
From: Lauren Weinstein <[EMAIL PROTECTED]>
Date: August 12, 2006 6:45:41 AM EDT
To: [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED]
Subject: Your Cable Company -- powered by the guy with the
extension cord
Dave,
Last night at around 2:15am (yup, everyone's just leaving the bars)
my area had a widespread power failure when someone wrapped
themselves around a main distribution line power pole (this is a
Friday and Saturday night tradition of course). While LADWP started
on it pretty quickly, power was not restored for around seven
hours.
That long an outage is enough to expose one of the serious weak points
in our telecom networks -- remotely situated batteries. They don't
last very long without external charging power, and we already know
that microcell sites tend to go down quickly for this reason when
power fails.
Early this morning when I started walking the area to see the
effects, I quickly found an unmarked white bucket truck with engine
running, parked at a nearby corner, with an orange extension cord
running from its open hood to the open cable backup power box on the
nearby pole, containing what looked like about three gel cells.
When I went over and talked to the friendly cable guy splicing wires
on the back of his truck, he told me that he wasn't even trying to
charge the batteries, all he could do was try to keep the system
running from his truck until power was restored.
Cable modems? Cable VoIP? Our whole world of modern cable telecom,
dependent on a guy with an extension cord and an old bucket truck.
I found it rather amusing, in a "sad commentary" sort of way.
--Lauren--
Lauren Weinstein
[EMAIL PROTECTED] or [EMAIL PROTECTED]
Tel: +1 (818) 225-2800
http://www.pfir.org/lauren
Co-Founder, PFIR
- People For Internet Responsibility - http://www.pfir.org
Co-Founder, IOIC
- International Open Internet Coalition - http://www.ioic.net
Moderator, PRIVACY Forum - http://www.vortex.com
Member, ACM Committee on Computers and Public Policy
Lauren's Blog: http://lauren.vortex.com
DayThink: http://daythink.vortex.com
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