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From: barefoot@hobbes.ncsu.edu (Heath Roberts)
Newsgroups: comp.dcom.telecom
Subject: Re: Concerted Action
Message-ID: <16164@accuvax.nwu.edu>
Date: 18 Jan 91 20:32:58 GMT
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Reply-To: Heath Roberts <barefoot@hobbes.ncsu.edu>
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X-Telecom-Digest: Volume 11, Issue 46, Message 9 of 13


In article <16080@accuvax.nwu.edu> wmartin@stl-06sima.army.mil (Will
Martin) writes:

>What would happen if everyone (in the US, in North America, on the
>planet -- pick your favorite range) picked up the phone at the same
>instant and tried to make a *local* call?  (Yes, anyone who got

Depends on the type of switch. Some would handle this gracefully,
others can't. DMS (NT) switches limit dial tone, so the switch can
complete the calls it provides dial tone for. First come, first serve
kind of thing.  I'm not sure what would happen if the wait stack
filled up. Presumably it would issue a SWERR (software error) and the
call would die. Use up a lot of printer paper....

If the switch _did_ crash, it would take about four minutes to reload
its software, and things would be hunky-dory unless everyone was still
waiting for dial tone. In a worst case situation, current draw might
be great enough to draw down batteries, and if all those phones stayed
off hook, either the line modules would shut them down (auto recover
when the line goes back on hook) or telco employees might start
powering down line frames.

I don't think ATT switches handle bounds conditions this well. It'd
probably die, and they take longer to come back up. (I haven't worked
directly with them, but I understand it is on the order of half an
hour.)


Heath Roberts
NCSU Computer and Technologies Theme Program
barefoot@catt.ncsu.edu