[e2e] Agility of RTO Estimates, stability, vulneratibilites

[David P. Reed]

Sireen Habib Malik wrote:

> From a network's point of view, the users (of all kinds) generate data 
> - let us call it their on-phase. After downloading/generating data, 
> they go into thinking- or reading-phase. This is the off-phase. The 
> users remains in the on- and off-phase for randomly distributed times.

Sireen - models ~ reality, but NOT model == reality.   At the risk of 
belaboring the obvious (at least to me) - there is no "the network", 
just a collection of pieces loosely joined by agreements to cooperate, 
and there is no "user from the point of view of the network", there are 
just users who are not just people, but more and more consist of 
autonomous algorithms that mediate complex and persistent relationships 
among people.

For example, the Firefox browser does communications based on a model it 
constructs of what the user might decide to look at next.   This model 
is not in the network, nor is it in the user.   It may not even work 
very well.   Some network users are DDOS botnets, or out-of-control 
buggy communications.   The network

It's just plain not reasonable to say that "users" is a unitary concept 
subject to a stable model, just as it is not reasonable to say that 
networks (which include traffic shapers, MPLS, ...) are simple 
collections of queues and links. That's something that mathematicians do 
to map a real thing into a tractable problem space.   But it's a 
dangerous mapping, as I've learned over and over in my career.  On the 
one hand, you have to abstract in order gain one sort of 
understanding.   But the abstraction creates a brittle problem structure 
- knock one of the assumptions and the whole elaborate business falls 
over dead.

You can't describe why a rainforest behaves as it does by analysis at 
the level of van der Waals forces, nor can you by studying the genomes 
as encoded in DNA.   You need to understand such things as the sunspot 
cycle and the path-dependent evolutionary and development cycle as well.

My point about "incredibly useful" but containing an "essential lie" can 
be stated imprecisely as a statement that reductionism is insufficient 
to understand many very important phenomena that are VERY real-world.   
Read P.A. Anderson's famous article, "More is Different".   Or read an 
introductory complexity theory text about how heat conduction creates 
stable vortices in fluids of a stable size.

In other words, when you use the word "network" in the paragraph above, 
you are referring to something that exists *only* in the minds of 
professors of computer science, because they created it as a modeling 
tool.   The "network" we actually use is quite different.