[e2e] TCP un-friendly congestion control

[Barney Wolff]

On Sat, Jun 07, 2003 at 11:21:37AM -0400, J. Noel Chiappa wrote:

> Your point is definitely not relevant to my message, which related to the
> effectiveness of packet-drop based congestion control at very high speeds,
> and in particular the supposition that transmission-error-drops (which will
> increase in frequency as the link rate goes up, assuming a constant BER) will
> add a lot of (unfilterable) noise to the congestion-drop signal, effectively
> rate-limiting TCP on very-high-speed paths to a speed far below that of the
> actual bottleneck.

If random BER is the problem, isn't FEC the solution?  Any scheme that
can't differentiate between error drops and congestion drops must
ensure that error drops are much less frequent than congestion drops.

Years ago there was the concept of "error-free seconds" that dealt with
this very issue, that higher-speed links need better BER to maintain the
same average time interval between errors and clustered bit errors are
not the same as random bit errors.

-- 
Barney Wolff         http://www.databus.com/bwresume.pdf
I'm available by contract or FT, in the NYC metro area or via the 'Net.