On 30/11/2018 19:23, Spencer Dawkins at IETF wrote:
This is Mirja's comment, but ...
On Fri, Nov 30, 2018 at 10:12 AM Mirja Kühlewind <i...@kuehlewind.net
<mailto:i...@kuehlewind.net>> wrote:
Mirja Kühlewind has entered the following ballot position for
draft-ietf-opsawg-ipfix-bgp-community-11: No Objection
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COMMENT:
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One comment on section 1:
"For example, they can shift some flows
from congested links to low utilized links through an SDN controller
or PCE [RFC4655]."
I'm not aware that ipfix information is commonly used for dynamic
traffic
adaptation and I'm not sure that is recommendable. C
I'm agreeing with Mirja here.
We've spent a LOT of time not recommending dynamic traffic adaptation.
Probably half my responsibility as AD for ALTO was repeating "you
can't react based on changes to that attribute without taking chances
on oscillation" like it was a mystical incantation, and I wasn't the
first AD to have that conversation repeatedly.
Yes, I understand the ARPA net had exactly that problem at one stage and
had to be converted from using a delay based metric to a fixed metric.
I would be happy to hear that all those problems are solved, but I
haven't heard that yet. Do the right thing, of course.
Even "can shift some flows from persistently congested links to
underutilized links" would cause me less heartburn.
There is no such thing as permanent in network paths!
Like many control problems the first order solution is to damp with a
suitably long time constant, but infinity, i.e. permanent, is not a
satisfactory choice either.
- Stewart
Spencer
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