Re: BER and TCP/IP performance

From: Eric Travis ([email protected])
Date: Wed Mar 31 1999 - 15:19:28 EST


>Having said all that, my understanding is that to get 'decent'
>performance out of TCP (ie., a window > 1) packet losses should
>be limited to less than 1 per RTT.

Only if the definition of 'decent' translates to an effective
cwnd of ~1 or 2 segments :o(

You really want your (non-congestion based) losses bunched within
single RTTs that are fairly widely spaced [how wide will depend
on what your optimal cwnd for the path would be]. Otherwise TCP
will be severely under driving your link.

>There was a thread recently on the pilc list (see
>http://pilc.grc.nasa.gov/pilc) on channel BER that might be
>of interest to tcpsat participants. I am crossposting to the
>pilc list and would like to recommend continuing this
>discussion there.
 
Is it me, or haven't we already seen this thread replay
itself a half dozen times already on this *very* mailing
list? :o)

This seems like a good time to plug the excellent tcpsat
mailing list archive that Mark makes available off of:

http://tcpsat.grc.nasa.gov

I'm confident that if one pulls the archive and does a
grep on BER, errors or loss - you will be able to extract
virtually all the collected wisdom/opinions from the cyclic
(and often passionate) "BER Wars" thread that appear every
2-3 months during 1998. I'm pretty sure it is all there
already (several times).

The stuff its there for those who want to dig it out;
Archives are there available, so let's not replay the
old stuff again on either tcpsat or pilc? New stuff
would be fantastic.

Eric



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