Subject: RE: [Ieprep] draft-ietf-ieprep-requirements-00.txt

From: "Gunn, Janet NE" <[email-masked]>
Date: Thu, 11 Jul 2002 10:38:23 -0400

I guess I am still not being clear.

While overprovisioning is definitely a "good thing" from a performance
perspective, it is not a panacea.

No matter what the ratio of core capacity to edge capacity, I suspect that
SOMEONE could come up with a "virus" (using that term in its most general
sense) which could use up enough of the core capacity to cause congestion.
For instance, it is within the realms of possibility for malicious code (or
even an innocent error) to corrupt switches and routers.  Remember when an
entire frame relay network went down due to a software upgrade?

So adding more capacity isn't the only answer.  And implementing security
measures isn't the only answer.   It would also be a "good thing" to have
some sort of contingency plan for what to do (specifically for IEPREP
traffic) IF there is congestion in the core.

To make a (rough) historical analogy, the Maginot line was a "good thing",
but it wasn't sufficient.  And making the Maginot line taller and more
heavily armed wouldn't have helped.  What would have helped would have been
to have some contingency plans for what to do IF the Germans got
through/around the Maginot line.

That is my only point.  Anytime someone says "X can't happen, therefore I am
not going to worry about X", I start to worry.

Now, maybe the probability of something/someone causing congestion in the
core is so low, and the cost of any kind of contingency plan (whether just
for IEPREP, or for all legitimate traffic) is so high that "we just have to
live with it."  OK, that I can accept.  But not even EXAMINING possible
contingency plans because "it can't happen" seems short sighted to me.

Congestion is much more likely at the edges, and our primary focus should be
there.  But we shouldn't ignore the core.

Janet

-----Original Message-----
From: Beard, Cory [mailto:[email-masked]]
Sent: Wednesday, July 10, 2002 5:51 PM
To: ieprep; Gunn, Janet NE
Subject: RE: [Ieprep] draft-ietf-ieprep-requirements-00.txt

> -----Original Message-----
> From: Gunn, Janet NE [mailto:[email-masked]]
> Sent: Wednesday, July 10, 2002 1:58 PM
>
> My point was more that the possibility  of virus attacks makes the
> assumption that "the core is overprovisioned and will never be short
of
> bandwidth for emergency services" a bit less sure.
> 

Janet,

My challenge to you or Stu is to prepare a design criteria by which
overprovisioning would be *acceptable*.  It is another issue to see if a
service provider could actually provision to that level (which you
doubt).

How about this (as Ran said) - the sum of all access rates is less than
the rate of the core link?  Maybe the core also has to be fully
connected, so no merging of bulk traffic streams occurs in the core?

Cory

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From: Randy Bush <[email-masked]>
Date: Thu, 11 Jul 2002 12:50:56 -0700

> sense) which could use up enough of the core capacity to cause congestion.

and similarly, someone could come up with an attack on the complex qos
systems you seem to be advocating to overcome this.

randy