[e2e] Why don't we talk about segments/objects instaead of layers? Re: Lost Layer?
detlef.bosau at web.de
Tue Feb 18 07:54:31 PST 2014
Am 18.02.2014 15:50, schrieb dpreed at reed.com:
> First of all, I am well trained in both queueing theory and control theory. If you want to talk about the mathematics of optimal control in non-guassian, non-poisson systems that have coupling between service rate and request rate, I'm your man. You guys are so far less informed about the fundamental theory, it's sad.
Obviously not enough.
The whole situation is (extremely well!) comparable to our current
macroeconomics situation - and you are trapped in exactly the same
pitfall as Ben Bernanke, Wolfgang Schäuble, our Iron Lady (AKA "The
Nought"), President Obama and most of the world:
Irving Fishwer was awarded the noble price for the concept of
monetarism. If the money supply is perfect, anything is perfect.
Refined by Milton Friedman: The only important thing is the money
supply, so we must control the money supply.
I think it will take a second world wide crisis in economics until we
eventually understand, that the money supply is simply not the matter of
interest, but the distribution of assets is the very point. I don't
know whether half of Greece's population must starve to death or whether
Larry Fink must have his teeth replaced by diamonds first, but at the
end of the day, we will understand that any successful control system
requires two inevitable elements:
First a correct system model, second a correct understanding what should
Both failed in both cases, in economy (where the monetaristic syststem
is simply nonsense and controlling the money supply is even more
nonsense, but perhaps Larry Fink enjoys fried dollar bills with a tasty
sauce) and in networks as well.
We focus on the amount of data passing around in the network, excuse me,
that simply does not matter, that was clear even in 1972 when we dropped
Davies isarithmic approach which was exactly the same.
Today whe have thousands of reasons why a CWND of, say, 1 MByte is
absolutely correct for a certain TCP connection.
Unfortunately the mobile node who surfs the Internet moves aside some
centimetres and his radio interface suffers from multipath intereference
- and the path cannot carry 1 MByte any longer but only 100 kByte. In
that case, we can simply forget all mathematical models and statistics
and control theory - or we could apply it correctly.
Basically, this is absolutely no rocket science. But it requires the
courage to eventually address the right things.
And the first thing to address is the word "congestion". We are talking
about a chain of flow control problems here - no TCP sender is
interested in what a final receiver will accept but what the next hop
will accept! And the plant from sender to receiver is not a "stationary
telephone line with some well defined capacity", so we can play Telix
and Kermit about it but it is much more complex and our models are way
to coarse here.
I have to apologize for being upset. But the analogies to macroeconomics
are evident here - and perhaps it is not shon on national TV or on CBS,
but there are people starving to death because some lunatic politicians
and economists address the wrong things!
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