[lwip-users] Re: Long(er) delay to PC ACK when serving images

[Alan Lamphier]

For reference... trying to accelerate large data file transfers by reducing PC
time to ACK

This thread started me on some experiements, trying to quickly 'throttle-up' the
connection packet size to fool (quickly calibrate?) the slow start-up or
congestion control.  May not be accurate in reality, but was the idea in my 
mind.

What worked for me...
I quickly found that the first image packet size (in response to GET) could not
exceed half my configured MSS=1460.  The second packet size could not exceed
1460-(first size).
>From there I tried ramping up the packet size 100 bytes per packet - it worked,
no long delays to PC ACK.
After playing with the 'ramp' rate, I eventually found it worked fine taking the
third packet and beyond to the 1460 byte limit (although, I thought at one point
the delays came back if I ramped too fast?).

I don't know that it will work one day or one computer to the next, but perhaps
my experience will help someone else.  The modification changed my tests from
'dialup-like' to 'broadband-like' impressions of the transfer (I don't currently
have transfer rate numbers for comparison).

Best regards,
Alan