[GreenKeys] Subject: RE telecommunication infrastructure vulnerabilities

[Wa3frp]

This is partially true 

but 

the facts are that the Internet is much more resilient than the dedicated point to point truck circuit network used to be.  Even with diverse routing, nothing beats the Internet for rerouting and retransmission.

But the switched telephone network (at least from an AT&T perspective) is not routed over the public Internet but over the private and dedicated 12.xx space that AT&T maintains and that is built on all SONET technology that is far superior to anything that was available in the electromechanical switching days. Six 9's reliability is now easily achieved.  I know as I saw it in action as my company's private data network that I oversaw until 2004 that was composed of 500,000 miles of WAN went from 99.99 percent availability to 99.9999 percent availability. This is quite a jump when you do the math.  Six minutes of downtime a year!

The reasons that the cellphone sites failed on 9-11-2001 have little to do with the underlying backbone and more about how the cell sites are powered and the capacity of the cell sites to take a 500% + increase in call volume. In every one of these disaster scenarios, the increase in call volume is what causes the cell and landline phone network to buckle.

Previously, look at any snow day in the northeast in the 1950s, 1960s, 1970s, 1980s, etc.  The older electromechanical phone system could not put out simple dial tone.  Too many people would go off hook at the same time, and the markers could not find an idle register. Two many folks with time on their hands would raise the call volume just enough to flood the system with call requests. In that case too, the trunks, designed to P10 would also get saturated resulting in fast busies and a lost calls held scenario as the party would simply go off hook again and tie up the next idle register.

Today, the telephone companies (at least AT&T) mitigate the lack of trunking issues by turning the network into a largely one way outbound network from the disaster site.  This allows the folks the disaster area to be able to call out while largely deflecting folks trying to call into the disaster site.  Why?  Because as soon as the news hits, everyone across the country tries to call relatives and friends that they know in the disaster location.  It is human nature. But, this overwhelms the telephone network and ties it into a knot.  Better to allow those in the disaster to call out as one call out to a relative or friend allow the word to get out "I'm OK"  to spread within a family or group of friends.

So, the older telephone network had its problems too.  

The question becomes "are things better today"?  The answer is yes by a very large margin. You can't compare the older T1 network with repeaters every 6000 feet to the fiber network using SONET technology where the repeaters are ten of miles apart.  And the fiber repeaters are self-powered. 

EMP - yes - network designed to handle this.   Satellites - not used for the voice telephone network due to echo and delays.

Comments?

73 Russ WA3FRP 

Message: 4
Date: Wed, 12 Oct 2011 15:53:26 -0600
From: Bryan Brodie <greenkeys at vaporland.com>
Subject: [GreenKeys] telecommunication infrastructure vulnerabilities
To: greenkeys at mailman.qth.net
Message-ID:
	<CAO+aD=zjW46q0VSjTCYQBhJu87wDkZJxo2VfyyVAQDLa-7rvLQ at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

As the telco veterans on this list may already know, vast portions of
telephone voice communications are now routed over the public
internet.

Bye bye resilient electromechanical switching and isolated
communications networks. Hello digital transmission over the public
internet with all of the associated risks and cost savings. (But, for
the time being, next quarter telecom profits are looking good!)

On September 11, 2001, landlines kept working even as cellphones
failed. This will not be the case next time. One EMP or several failed
satellites later, our telecommunication infrastructure will become a
pile of "obsolete junk".

I should note that I take no satisfaction from this.

From: hwhall at compuserve.com
To: GreenKeys at mailman.qth.net
Date: Tue, 11 Oct 2011 20:59:49 -0400 (EDT)
Subject: Re: [GreenKeys] an idea

 If you rely on the phone company landlines, the event that wipes the
computers will take it down, too, I imagine. It's computer switched,
optic fiber connected (with solid state optical signal boosters all
over), and so on. In the event of that flare, the power lines are
going away, too, so much of our ham stations will be offline.
--Wayne
 WB4OGM


Russ - WA3FRP
wa3frp at aol.com