Subject: RE: [Ieprep] Re: PSTN collapse

From: "Dvorak, Charles A (Chuck), ALASO" <[email-masked]>
Date: Mon, 9 Dec 2002 23:59:08 -0500

Fred

You said:

<snip>
> 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. 
<snip>

Thanks for correctly pointing out that even the Internet needs the
physical layer :-)

Many of the statements made about the PSTN here have been so biased that
they do not deserve a reply. True, there are some isolated problems that
continue to plaque some carriers, but for the most part in the switched
network, things are dynamic (like the Internet) and there is no single
point of failure, and in fact pretty sophisicated techniques are used
(like the Internet). 

For example, as long as traffic gets into AT&T's network, where we have
had real-time network routing for many years and dynamic routing _since
1984_, traffic almost always gets through. This was evident on 9/11 when
we carried 50% more traffic than the usual load. 

But of course if the unprotected access pipe of _any_ user is down, any
core network (PSTN or the Internet) never sees the traffic. Take out a
single, dedicated data pipe that carries traffic to an access
router...and the Internet "collapses" (at least for users of that pipe).

The real issue is when people still have access (e.g., wireless) but
there is severe network congestion, say due to a disaster, what do you
do in the network? You've got a bottleneck, and while the PSTN and the
Internet deal with bottlenecks differently, the issue for this group
should be: When some deserving (emergency-related) traffic merits
priority treatment, and authorized users so authenticate, how does the
network increase the probabilty of completion over non-prioritized
traffic? (Note I did not say guarantee...this is only done in private
networks)

The PSTN does this today; a bit gets set in SS7 and the switches give
priority to such calls. Nothing is guaranteed, as under emergency
situations no one knows what facilities remain and what the traffic will
be. But at least the emergency traffic gets prioritized treatment. 

It seems to me we could successfully do something similar in IEPREP,
which would be a proactive step as opposed to PSTN-bashing, or some of
the recent personal attacks by others.

Chuck Dvorak

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---

From: RJ Atkinson <[email-masked]>
Date: Tue, 10 Dec 2002 09:39:46 -0500

On Monday, Dec 9, 2002, at 23:59 America/Montreal, Dvorak, Charles A 
(Chuck), ALASO wrote:
> do in the network?

During 9/11, the Internet did NOT suffer significant network congestion 
inside
the core (primarily because of massive over-provisioning, which ISPs 
find is
more cost-effective than deploying QoS).   As various people have been 
noting,
there were particular access links that were cut or congested, but that 
is
a separate issue.  And in many cases, the Internet was able to route 
around
fibre cuts that did cause problems for the RBOCs.

Nor was 9/11 an isolated case.  A long list of natural disasters (e.g.
Kobe, Loma Prieta, Hurricane Andrew, Northridge, various twisters) are
good examples where the telephone system did suffer significant 
congestion
(resulting in inability to place calls) but the Internet did NOT suffer
significant congestion (resulting in people using the Internet 
successfully
to communicate even though their phone service was unavailable due to 
switch
congestion).

> You've got a bottleneck,

First, folks need to demonstrate that the Internet backbones have 
suffered
or are likely to suffer severe congestion.  So far, all the evidence, 
including
the recent NAS study, indicates that this has not happened so far -- 
and there is
nil evidence that it is likely to happen in the near future.

> and while the PSTN and the

IP has packets, and does not have "calls" so there is no concept in IP
of "call completion".  Basically, some folks are trying to apply a 
circuit-switched
network concept to a packet-switched network -- which a bunch of folks 
here
think is a broken approach.  To be fair, it is as broken as trying to 
apply
a packet-switched network concept to a circuit-switched network.

So if anyone wants to make headway with one's agenda, one needs to 
first convince
most folks here that one's perception of the problem is reasonable.  
Until
someone does that in this group, the group will remain stalled 
indefinitely,
because "rough consensus" is required to make progress in IETF (and we
don't have rough consensus right now on what issues this group ought to 
focus on).

Ran
[email-masked]