[c-nsp] what limits bw on a tcp stream?

[Adrian Chadd]

On Fri, Nov 16, 2007, matthew zeier wrote:
> 
> I have gear in Amsterdam and in San Jose.  Pushing log files from 
> Amsterdam to San Jose through rsync seems to top out at 7Mbps even 
> though the box doing the push is pushing much more out to the Internet. 
>   If I run several rsync's it goes quicker so I know I have the bandwidth.
> 
> What's limiting me?

RTT + TCP window sizes? Assuming say 50ms RTT (what is it?) then
the TCP rate at 64k window sizes without SACK, etc is ~ a megabyte/sec?
(1.2 megabytes, so ~10mbit.)

RTT + rsync protocol? I'm not sure if the -B option to set the blocksize
does what you want though.



Adrian