Subject: [Ieprep] Re: PSTN collapse

From: [email-masked]
Date: Mon, 9 Dec 2002 17:17:38 EST

In a message dated 12/9/2002 3:59:12 PM Eastern Standard Time, [email-masked] 
writes:

> >       On Mon, 9 Dec 2002 [email-masked] wrote:
> >     > I don't consider inability to get dial tone as "collapsed".
> 
> No Dial tone = No connection (PSTN) 
> Welcome to the world of SIP, where you get dial tone but still
> remain disconnected. This is due to the interesting concept of 
> separation of session establishment and resource reservation in
> SIP based systems. If for some reason the resource reservation 
> fails, the call will be set up even though network doesnt support.
> So, your phone may be ringing even though the network cannot
> support the call. It was one of the problems discussed during
> initial days of SIP. But, there are many proposed fixes to avoid 
> the above situation. 
> 
> 
> >     > Can someone give an example of when and where "the PSTN 
> > collapsed"
> >     > during an emergency?
> 
> Please go through all the trade press articles about 9/11.
> 

As usual, I see that you can not answer a direct question regarding a wild 
claim about how bad the PSTN is. I don't have time to read all the trade 
press articles on 9/11, certainly not all the ones that tell about how 
wonderful the Internet performed. (I don't dispute that.) I'd like a pointer 
to one that describes a "collapse" of the PSTN, on 9/11 or any other time.

I was:
- in San Fransisco when the earthquake hit in 1989
- in South Florida when the big hurricane hit
- in Baltimore when a hurricane went over and we lost power for a week
- at a meeting in the area right after Hinsdale burned (we waited on the 
ground in Miami an extra 2 hours while ATC circuits were rerouted.)

(Sounds like disasters follow me.)

and in none of these cases did the PSTN "collapse". There were local outages 
depending on the condition. Sure, if a tree fell across the wires to your 
house, you didn't get dial tone. That's not a "collapse" of the PSTN!

Mike Pierce

---

From: Fred Baker <[email-masked]>
Date: Mon, 09 Dec 2002 15:24:25 -0800

At 05:17 PM 12/9/2002 -0500, [email-masked] wrote:
>I'd like a pointer to one that describes a "collapse" of the PSTN, on 9/11 
>or any other time.

The PSTN did not "collapse". There were a number of switches taken out, one 
way or another, and telephone service was adversely affected as far away as 
(according to anecdotal reports) Chicago. To say that the PSTN worked 
properly on, say, Manhatten Island after 9:03 on 9/11/2001 would not be 
accurate either. I think that's what he is referring to.

By the way, we're having the same behavior in North Carolina at the moment. 
They had an ice storm last week, and while Internet connectivity and 
therefore Cisco's VoIP networks are still working just fine, the local 
telephone company seems to be having some challenges. No slight intended 
against said telephone company; there any number of last mile problems, and 
when the wire is busted, it really doesn't matter what kind of traffic 
you're trying to run over it. But their fundamental problem is with the 
architecture of the "intelligent network": it is subject to brittleness 
under failure conditions where Internet technology will automatically 
re-route.

I have an amusing email from an engineer who reports that he is working 
from home today and has call-forwarded his home phone to his desktop VoIP 
phone. He had a call this morning from the phone company, who wanted to 
know when his service had been restored. They didn't like being told that 
their dial tone was still unavailable and he was being serviced by VoIP 
from 3000 miles away. 
_______________________________________________
Ieprep mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/ieprep

---

From: RJ Atkinson <[email-masked]>
Date: Mon, 9 Dec 2002 18:30:05 -0500

On Monday, Dec 9, 2002, at 17:17 America/Montreal, [email-masked] 
wrote:
> As usual, I see that you can not answer a direct question regarding a 
> wild claim about how bad the PSTN is. I don't have time to read all 
> the trade press articles on 9/11, certainly not all the ones that tell 
> about how wonderful the Internet performed. (I don't dispute that.) 
> I'd like a pointer to one that describes a "collapse" of the PSTN, on 
> 9/11 or any other time.
>
> I was:
> - at a meeting in the area right after Hinsdale burned (we waited on 
> the ground in Miami an extra 2 hours while ATC circuits were > rerouted.)
>
> and in none of these cases did the PSTN "collapse". There were local 
> outages depending on the condition. Sure, if a tree fell across the 
> wires to your house, you didn't get dial tone. That's not a "collapse" 
> of the PSTN!

Mike,

	You are seriously inconsistent with yourself.  Access links are 
entirely
comparable to "wires to your house" -- because those are common kinds 
of access
links.  Yet, you are totally worked up about IP congestion on access 
links even
though most access links only have one site (e.g. house in the case of 
DSL)
behind the link.  If local outages don't count for the PSTN, then it is 
only
fair, reasonable, and logical that they don't count against the 
Internet.

	You also selectively reply to email.  Several folks gave specific 
examples
where access wires were in place, yet dial tone did not exist for long 
periods
of time (e.g. Bill Woodcock's Loma Prieta example, among several posted 
here
recently).  You seem to have a kind of selective amnesia to facts that 
you
find inconvenient.

	Your hypocritical behaviour is impressively bad -- accusing others of
not providing a direct response while you fail to acknowledge that 
numerous
specific PSTN collapse events HAVE been presented here recently -- and
presented by several different folks.

Ran
[email-masked]

---

From: RJ Atkinson <[email-masked]>
Date: Mon, 9 Dec 2002 18:54:38 -0500

My employer has a VoIP internal phone system also (built out of 
different
make/model equipment than Fred's :-).  Our RTP office is similarly up 
and
running today for IP and our internal-only VoIP, though many homes and 
businesses
lack telephone service in RTP.

By the way, the CATV infrastructure in RTP seems to be more robust than
the PSTN infrastructure during this particular weather-related scenario.
A nice artifact of IP is that it can use not only the last-mile PSTN
infrastructure, but also wireless, CATV, and other kinds of 
infrastructures.
And with dynamic routing, IP automatically finds the best remaining 
path,
without any special configuration needed to enable that capability.

Ran
[email-masked]

On Monday, Dec 9, 2002, at 18:24 America/Montreal, Fred Baker wrote:
> By the way, we're having the same behavior in North Carolina at the 
> moment. They had an ice storm last week, and while Internet 
> connectivity and therefore Cisco's VoIP networks are still working 
> just fine, the local telephone company seems to be having some 
> challenges. No slight intended against said telephone company; there 
> any number of last mile problems, and when the wire is busted, it 
> really doesn't matter what kind of traffic you're trying to run over 
> it. But their fundamental problem is with the architecture of the 
> "intelligent network": it is subject to brittleness under failure 
> conditions where Internet technology will automatically re-route.

Aside:
	It also matters that much of the RTP PSTN infrastructure is on poles.
Poles have much better MTTR but much much worse MTBF for weather damage
(e.g. hurricanes, ice storms).

> I have an amusing email from an engineer who reports that he is 
> working from home today and has call-forwarded his home phone to his 
> desktop VoIP phone. He had a call this morning from the phone company, 
> who wanted to know when his service had been restored. They didn't 
> like being told that their dial tone was still unavailable and he was 
> being serviced by VoIP from 3000 miles away.