[ih] Why did congestion happen at all? Re: why did CC happen at all?

[Miles Fidelman]

Regarding algorithmic solutions:

Detlef Bosau wrote (in different messages):


Also, in reference to earlier comment re.:
> There are dozens of all days life examples where resources must be
> allocated or assigned, we have well proven algorithms for these
> purposes. E.g. in Germany, you can travel by car from Flensburg to
> Füssen. And there is no need for probing, no need for dropped cars and
> car corruption is considered an accident./ 

Not only is this not the case, the situation is simply different: Cars 
are self-driving, with drivers making moment to moment decisions as to 
their routing, potentially with input as to global traffic conditions -- 
last time I looked, packets can't do that (though, admittedly, routers 
are doing that for them, as they make next-hop decisions based on the 
state of routing tables).

It's an engineering decision as to which is more effective and efficient 
- dropping packets in the face of congestion, with end-to-end 
retransmission, or buffering them in the switches (store-and-forward).  
An awful lot of experimentation and real-world practice suggests that 
dropping packets is a lot simpler, and uses fewer resources, than a 
store-and-forward or connection oriented approach.  The equation changes 
under conditions of high-delay links, network disruption, and such - 
hence the use of store-and-forward in some of the protocols being 
developed for delay/disruption-tolerant networks - particularly where 
inter-planetary distances and delays are a serious consideration.

>
> Or, since today it was mentioned that our German secretary of defense,
> Ursula von der Leyen, has seven children. I'm not quite sure whether she
> is going to solve the problem in the Ukraine by "probing". Send four
> children to war, if some are dropped halve the window and send only two,
> now the next try is stop and wait....
>
> (Rumour says, that the US Air Force actually assesses traffic control by
> probing and drop,  I think the project is conducted near to Ramstein
> Airbase.)

Ummm.... you're missing all the stuff going on behind the scenes, in the 
form of routing protocols.  Packets are not sent off willy nilly in all 
directions - they're sent in the directions indicated by routing tables 
that are updated based on, among other things, resource congestion 
around the net.




-- 
In theory, there is no difference between theory and practice.
In practice, there is.   .... Yogi Berra