*BSD News Article 84696


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From: djb@koobera.math.uic.edu (D. J. Bernstein)
Message-ID: <1996Dec1321.21.47.28981@koobera.math.uic.edu>
Date: 13 Dec 1996 21:21:47 GMT
Newsgroups: comp.mail.sendmail,comp.mail.smail,comp.unix.bsd.freebsd.misc
Subject: Re: sendmail vs. qmail
References: <57tf61$gq7@raven.eva.net> <58h6r1$8ik@ezekiel.eunet.ie> <1996Dec1005.15.53.2968@koobera.math.uic.edu> <SHALUNOV.96Dec13131524@math.wisc.edu>
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stanislav shalunov <shalunov@math.wisc.edu> wrote:
> Do you claim that opening 10 connections in parallel and transmitting
> the same data (except RCPT line which doesn't affect data length much),
> about 5K, is faster than transmitting the same 5K one time?

It depends. There are literally dozens of variables that you've failed
to specify.

> Do you claim that the worse is connection the more is gain?

What do you mean by ``worse''? Lower bandwidth? Higher traffic? Higher
line latency? Higher packet drop rate? Higher bit error rate? Higher
round trip time? Higher SMTP server latency? Higher overall server load?
Higher DNS latency? Lower DNS hit percentage? Or something else?

> And, furthermore, do you claim that you have proven it with actual
> measurements?

I don't know what you mean by ``it.'' What are you referring to? If you
don't understand something I've said, please quote it.

> P. S.: would you accept the following model of SMTP transmission:

What do you mean by ``accept''? If you mean ``would you blindly assert
that the following absurdly simple and incredibly vague model of SMTP
transmission produces accurate estimates of any quantity related to mail
traffic?'' then the answer is no.

---Dan
Put an end to unauthorized mail relaying. http://pobox.com/~djb/qmail.html