Re: [Bug-wget] Support for long-haul high-bandwidth links

[Andrew Daviel]

On Fri, 2 Dec 2011, Daniel Stenberg wrote:

> > I may be wrong, but I thought that to get significant benefit large windows 
> > had to be enabled on every router between the source and destination, which 
> > I did not think was the case on the public Internet.
>
> Not exactly, but in firewalls and NATs or whatever you have in between. It is 
> a TCP option, not IP: http://en.wikipedia.org/wiki/TCP_window_scale_option

I'm probably confusing that with jumbo frames, which we had 
experimentally enabled on a long distance "lightpath".
http://en.wikipedia.org/wiki/Jumbo_frames
http://www.bigbangwidth.com/pdf/ADS.pdf

In studies done a while ago now (2001), people had tuned TCP parameters
including the buffer size, but still got better performance from 
multi-threading
http://hepwww.rl.ac.uk/Adye/talks/010402-ftp/html/index.htm


ES.net is still recommending multi-thread transfer in pages updated this 
year, though as you say auto-tuning the congestion window is now 
mainstream
http://fasterdata.es.net/fasterdata/host-tuning/
http://fasterdata.es.net/fasterdata/data-transfer-tools/

--
Andrew Daviel, TRIUMF, Canada