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  1. #1
    danny burstein
    Guest
    In <[email protected]> Steve & Susan <[email protected]> writes:

    >On Fri, 15 Aug 2003 06:01:30 -0700, Group Special Mobile
    ><[email protected]_to.reply> wrote:


    >>No system whether it's land lines or mobile phones is engineered for
    >>disasters


    >You mean no post-cold war, post-deregulation system is engineered for
    >disasters. Old wireline "Bell System" infrastructure was absolutely
    >engineered for disasters. They were a vital partner in our nation's
    >homeland security in the 50's, 60's and 70's.


    Not quite as easy as that. While the phone equipment and network in the
    days of One Bell System, It Works, would last through just about anything
    imaginable, the network was NOT designed to be non-blocking.

    In other words, a typical telco switch would only allow, say, 5 percent of
    the subscribers to be on the phone at any one time. And calls between
    central offices required trunks which were similarly limited.

    There's a very detailed science in making these designs - trying to figure
    out what capacity a switch needs. Check out "erlang".
    --
    _____________________________________________________
    Knowledge may be power, but communications is the key
    [email protected]
    [to foil spammers, my address has been double rot-13 encoded]



    See More: telco resorces, was: NY Blackout and Cell Usage




  2. #2
    Steve & Susan
    Guest

    Re: telco resorces, was: Re: NY Blackout and Cell Usage

    On Sat, 16 Aug 2003 05:03:32 +0000 (UTC), danny burstein
    <[email protected]> wrote (after I said):

    >>Old wireline "Bell System" infrastructure was absolutely
    >>engineered for disasters. They were a vital partner in our nation's
    >>homeland security in the 50's, 60's and 70's.

    >
    >Not quite as easy as that. While the phone equipment and network in the
    >days of One Bell System, It Works, would last through just about anything
    >imaginable,


    I thought that's what I said. In fact, there are great pictures and
    descriptions of old (and now defunct) AT&T Long Lines facilities all
    over the web - complete with nuclear blast detectors and electric
    combustion toilets. They just don't make those anymore. I'm still
    looking for a good 220 Volt toilet for my garage.

    >the network was NOT designed to be non-blocking.


    I didn't say that.

    But, anyway, the network now holds some of that capacity in abeyance
    for continuity of government. Pretty important because what emergency
    manager can compete with everyone calling home to tell someone to turn
    their TV on (oh, wait, there was no TV)?

    >There's a very detailed science in making these designs - trying to figure
    >out what capacity a switch needs. Check out "erlang".


    Erlang B is a fine algorithm as a STARTING POINT. Empirically, other
    factors are important in considering how many trunk groups are
    actually needed. For instance, (a real-life situation in E 9-1-1
    infrastructure) is it wise for an ILEC in a given area to concentrate
    250 square miles containing one small city and diverse rural areas,
    each with with its own uniquely identifiable center of community, into
    only three trunks given simply following Erlang B?

    Steve



  3. #3
    David S
    Guest

    Re: telco resorces, was: Re: NY Blackout and Cell Usage

    On Sat, 16 Aug 2003 11:21:42 -0500, Steve & Susan <[email protected]>
    chose to add this to the great equation of life, the universe, and
    everything:

    >I thought that's what I said. In fact, there are great pictures and
    >descriptions of old (and now defunct) AT&T Long Lines facilities all
    >over the web - complete with nuclear blast detectors and electric
    >combustion toilets. They just don't make those anymore. I'm still
    >looking for a good 220 Volt toilet for my garage.


    I visited one of those places in high school (ca. 1982). On the surface
    there were a few shacks, but you went into one and down the stairs and it
    was a HUGE complex. They said it was designed to withstand 1 megaton at 1
    mile, except that they never installed the blast doors on the ventilation
    system (or something like that). There were rows of HUGE lead-acid
    batteries (I remember them as about 4 feet high, but I may be wrong) with
    HUGE busses running across the tops (I thought they compared to the floor
    joists in my house), which the guide said were connected directly in
    parallel with the power supply so that A: they would get a constant trickle
    charge; and B: there would be no switching delay when the power went out.
    And their only purpose was to keep the center up for the 110 seconds it
    took for the generator to get up to speed (actual battery capacity was
    measured in minutes or hours). They had fuel storage to run it for a
    certain number of days (60?), but normally only kept about 1/2 or 1/3 that
    much on hand. The longest the generator had ever run was (IIRC) 82 or 84
    days (longer than the fuel capacity, so they'd had to get at least one
    delivery) due to some problem with Com Ed.

    They were just starting to experiment with fiber optics. I think they had
    *1* guy who was allowed to touch the fiber.

    David Streeter, "an internet god" -- Dave Barry
    --
    http://home.att.net/~dwstreeter
    Expect a train on ANY track at ANY time.
    "Tourist: Who are you people?
    Striking screenwriter: We're writers.
    Tourist: What are you striking for?
    Writer: More money.
    Tourist: How much do you earn?
    Writer: $350,000."
    - as reported by Bernard Weintraub, New York 'Times'




  4. #4
    danny burstein
    Guest

    telco resorces, was: Re: NY Blackout and Cell Usage

    In <[email protected]> Steve & Susan <[email protected]> writes:

    >On Fri, 15 Aug 2003 06:01:30 -0700, Group Special Mobile
    ><[email protected]_to.reply> wrote:


    >>No system whether it's land lines or mobile phones is engineered for
    >>disasters


    >You mean no post-cold war, post-deregulation system is engineered for
    >disasters. Old wireline "Bell System" infrastructure was absolutely
    >engineered for disasters. They were a vital partner in our nation's
    >homeland security in the 50's, 60's and 70's.


    Not quite as easy as that. While the phone equipment and network in the
    days of One Bell System, It Works, would last through just about anything
    imaginable, the network was NOT designed to be non-blocking.

    In other words, a typical telco switch would only allow, say, 5 percent of
    the subscribers to be on the phone at any one time. And calls between
    central offices required trunks which were similarly limited.

    There's a very detailed science in making these designs - trying to figure
    out what capacity a switch needs. Check out "erlang".
    --
    _____________________________________________________
    Knowledge may be power, but communications is the key
    [email protected]
    [to foil spammers, my address has been double rot-13 encoded]



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