NAP/ISP Saturation WAS: Re: Exchanges that matter...

Er. There's no such thing as perfect transport as long as TCP is
concerned. If end-hosts support large windows, even a single
TCP session will load the network to the point where it'll lose

What you say here makes sense to me. But, out of a 500
ping sample over the course of half a day, I was getting well
below one percent loss -- six months ago.

Most TCP sessins are pretty short, in fact. They simply have
no chance to open window. Also, there's a lot of old TCP
implementations which have window limited to 64Kb (or less!).

Now, my same sample group is going for more than three percent,
with many ten percent loss routes showing...

Well, nobody argues that Internet is overloaded. But the question
of how to measure the congestion is not as simple as just pinging.

The problem is that there's no reasonable way to learn loss
statistics from routers.


As for me, congestion exists if long TCP sessions can't adapt their
window sizes and packet drop if more than 3 - 5 % over connection line.

This means more than 1,000 - 2,000 tcp sessions through 2 Mbit link, for
example. Yes, IP is connectionless protocol, but Internet is not connectioonless
network in real life...