[rssac-caucus] FYI: CDAR Study Cannot Predict Stability of the Root Server System

[Daniel Karrenberg]

Fellow Caucus Colleagues,

I have a personal request for comments:
After some reflection I plan to submit the following comment about the
CDAR study. I would appreciate any comments or suggestions you might
have. Personal e-mail welcome.

Thank you for your time and consideration.

Daniel


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To whom it may concern,

The proposed core methodology of the study is a "quantitative model"
based on measurement of past behavior of the DNS root server system.
Such models of complex systems are by nature simplifications. They are
indeed very useful to identify possible instabilities in the real-world
system they are modeled after. However these models cannot predict the
*absence* of instabilities in the real-world system with any useful
level of confidence. In other contexts this is referred to as "Past
Performance is Not Necessarily Indicative of Future Results".

Our main comment and advice to the researchers is to carefully avoid any
perception that their results predict the absence of instabilities
unless the results solidly support such claims.

Our main comment and advice to ICANN is not to expect the study to
predict the absence of instabilities in the DNS root name server system
that are wholly or partly caused by root zone expansion. ICANN therefore
should make proper contingency plans for the unpredictable cases where
root zone expansion causes or contributes to instabilities in the DNS
root sever system.

Research is most useful and should be called scientific only when it can
be verified and possibly reproduced by other researchers and scientists.
Therefore we support the researchers intention to base their study on
openly available measurement data and meta-data wherever possible. Where
this is not feasible the observations and meta-data should at least be
available to other researchers under reasonable conditions.

Daniel Karrenberg
Chief Scientist
RIPE NCC, not speaking on behalf of the RIPE NCC


Relevant experience: 30+ years of operational experience in DNS; 15+
years of operational experience and responsibility for
k.root-servers.net; contributor to DNS software diversity by instigating
and helping with design and implementation of NSD 1.0, an authoritative
name server; inventor and principal implementor of 'dnsmon', the first
comprehensive and public monitoring system for high level DNS servers;
co-inventor and responsible for the initial deployment of RIPE Atlas,
the active measurement system proposed to be used in the study; ... .

ICANN entanglements: member of ICANN RSSAC since its inception and not
speaking on behalf of RSSAC either.