[e2e] Agility of RTO Estimates, stability, vulneratibilites

David P. Reed dpreed at reed.com
Mon Jul 25 12:59:29 PDT 2005


The most fundamental problem with RTO estimates in the Internet is that 
the most significant sources of measured variation (queueing delay, for 
example) are variables that are being used as signalling channels 
between multiple independent goal-seeking processes at multiple levels.

Note that the load distribution cannot be characterized by a stable a 
priori description, because load is itself responsive at all timescales 
to behavior of humans (users, app designers, cable plant investors, 
pricing specialists, arbitrage experts, criminal hackers, terrorists, 
network installers, e-commerce sites, etc.)

So you are fooling yourself if you start with a simple a priori model, 
even if that model passes so-called "peer review" (also called a folie a 
deux - mutually reinforcing hallucinations about reality) and becomes 
the common problem statement for a generation of graduate students doing 
network theory.  In my era, the theorists all assumed that Poisson 
arrival processes were sufficient.   These days, "heavy tails" are 
assumed to be correct.   Beware - there's much truth and value, but also 
a deep and profound lie, in such assertions and conventional wisdoms.

Those of you who understand the profound difference between Bayesian and 
Classical statistical inference will understand ...

That said,




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