Subject: [Ieprep] Re: PSTN collapse

From: [email-masked]
Date: Tue, 10 Dec 2002 10:18:30 EST

In a message dated 12/9/2002 5:57:59 PM Eastern Standard Time, [email-masked] 
writes:

Please provide reference to PSTN collapse (since i dont have any
access to ITU-T documents.) If local meltdown is not collapse,
then what is your definition of PSTN collapse? 

[MAP] I didn't start the reference to "PSTN collapse". I have no idea what it 
means, since it has never happened as far as I know, given any definition 
that I could think up. There is no ITU-T definition.

"Local meldown" within the PSTN, as you call, it is common due to unforeseen 
events (backhoes digging up thousand pair telephone cables, central offices 
burning, etc.) and local customers can not make phone calls. There has never 
been an argument on that. That is not "PSTN collapse". (Remember, the "N" 
means network.) In fact, the PSTN contains specific protocols to deal with 
these local ituations. But such "local meltdowns" are also common in the 
Internet. If the server that I am connected to goes down (or is "taken down 
for maintenance" as seems to happen weekly) I lose service and would not get 
a call through on my SIP phone either. Of coures, the number of "subscribers" 
affected by such a failure of a server is typically small, unlike the 100 
thousand or so when the Hinsdale central office burned. That isn't the point. 
The performance measure for this is the probability of any one "subscriber" 
being out of service (no dial tone) for how long per year. The overall 
performance for the PSTN (at least in the US not counting trees over wires in 
the local neighborhood) is on the order of minutes per year per subscriber 
(the infamous "5 nines").

For those who missed it, during the week of the IETF I was watching CNN news 
one night and at the end of the newscast, the announcer said "Send us email 
except when the server is down which is Thursday." Unfortunately, that is the 
common impression people have of Internet service.

Mike Pierce
Artel
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From: RJ Atkinson <[email-masked]>
Date: Tue, 10 Dec 2002 15:31:33 -0500

> common impression people have of Internet service.

Again you make misleading comments, confusing scheduled downtime for one
organisation's mail server with availability of Internet service.

Its just not helpful to the WG progress when you keep doing that 
stuff...

Ran