[e2e] Are we doing sliding window in the Internet?

Detlef Bosau detlef.bosau at web.de
Thu Jan 4 06:24:07 PST 2007

Ian McDonald wrote:
> You'll find that Linux is probably the most RFC compliant
> implementation of TCP. However Linux isn't perfect and the developers
> do as they want.
> I think the bigger issue is that there are academics in one corner and
> implementors in another and usually they are not the same people and
> often don't even talk to each other.


I basically disagree.

Sounds similar to a paper last year which I criticized and the answer 
was: "You can publisch results yourself!"

Correctness is not proven by acclamation. And if some implementation is 
buggy or not standard compliant this is not healed by a large number of 
implementors who do something wrong.

Last year, I had some look at some networking code in the BSD kernel and 
much of it reminded me of code, I´ve seen in the NS2. And there have 
been comments with names. With authors. And from that I guess, that many 
of the "academics" have done a great deal of implementation work, 
particularly in the field of TCP.

In addition, computer science is an engineering discipline. And in 
engineering, you _first_ do research, _then_ you test your protocols, 
_then_ you write the standards if the tests yield convincing results and 
further implmentations are to follow the standards.


The other way round is some kind of trial and error.

I think, we all remember the well known fortune cookie "If builders 
built buildings like programmers write programs, any woodpecker that 
came along would destroy human civilization." That directly applies here.

I pesonally find it difficult to have always the "state of the art" i.e. 
the actual standards of TCP in mind, but this my problem and I have to 
deal with it. However, TCP is not a meritocratic or implmentocratic or 
commerciocratic election and the winner is M$ for today and Linux for 
tommorrow and afterwards it´s Novell, and then I once again see one of 
these funny "TCP probing" papers where some guys propose a sophisticated 
test suite which standards they follow, if any.

I strongly believe in sound scientific work and standards which are 
based on that. And from that, implementations are simply to follow the 
standards - no ifs and buts.

We have learned this in any other field of enginieriung but computer 
science. However, it´s necessary for computer science to achieve 
maturity to catch up with other disciplines here. And I say this from my 
own experience in professional life, because other engineers often 
ridicule about CS or even take it not seriously - for exactly this reason.


> Linux is a meritocracy so if
> people from this list were to go over to the netdev mailing list and
> make a reasonable argument then it will get listened to.
> Ian

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