[e2e] Data + FIN
padhye at aciri.org
Thu Jan 25 21:32:21 PST 2001
> > As to *how frequently* it happens, somebody with ready access
> > to packet traces can better answer that question. Two years ago,
> > Anja Feldman gave me a number that was (I believe) on the order
> > of 40% of TCP connection were doing this, based on a packet trace
> > from AT&T.
I have written a TBIT (http://www.aciri.org/tbit/) test to check this. A
scan of about 10,000 web servers showed that web servers running Linux
2.0.35-37 (based on NMAP identification) are least likely to piggyback the
FIN on the last data packet. Overall, about 28% of the web servers did not
piggyback the FIN on the last data packet. There are a few caveats:
a. The 10,000 web servers are from a trace taken at a web proxy, this is
not a representative sample in any way.
b. I set the MSS to 536 bytes. I wonder if the results will be different with
a different MSS.
c. For each web server, I downloaded the base page (GET /). Unfortunately,
I did not keep track of the amount of data transferred. Richard's data
clearly indicates that this is important.
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