net.inet.tcp.inflight_enable

[Matthew Dillon]

:>     Try increasing net.inet.tcp.inflight_stab from 20 to 40 and
:>     see if that fixes ethe congestion window expansion problem.  I'm
:>     not sure why the congestion window isn't expanding.
:
:I tried it and put the results at the following page.
:
:  http://www.demizu.org/~noritosi/memo/2005/0711/
:
:I compared the throughput of BDP Limiting with the throughput of
:congestion avoidance in my environment.  In my environment, I saw
:that, if inflight_stab is lower than 50, the throughput of BDP
:Limiting is lower than that of congestion avoidance, because
:congestion window with BDP Limiting grows slower than that in
:congestion avoidance.
:
:As you know, in the congestion avoidance phase, congestion window is
:increased one MSS per RTT.  With BDP Limiting, congestion window is
:increased one MSS per several RTTs in my environment.
:
:Regards,
:Noritoshi Demizu

    It's still not operating quite as I would expect.  Could you compare
    the results for a very long transfer, like 100 MBytes ?  If those numbers
    are closer then it may well be that all I really need to do is give it
    a better initial bandwidth estimate.

					-Matt
					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>