Rsync in Half Duplex Mode

Adrian Cooke cooke at
Tue Oct 3 14:53:44 GMT 2006


I am wanting to use rsync over a really bad wireless link that only 
works in half duplex mode. It is not possible to tune the hardware to 
work in half-duplex mode so it is up to the Application layer to make 
the link work in half duplex.

I have done some simple tests now transfering a file over the link using 
tftp and using rsync. Tftp is a very simple protocol using UDP and a 
stop and wait protocol to transfer the file. It thus drops almost no 
packets during the communication but has very basic functionality. Rsync 
uses TCP and thus a lot of packets are dropped because of the communication.

Does anyway know if it is possible to get rsync to work in a half duplex 
way, possibly using UDP? Are there any patches out there that can do this?

If not how hard will it be to modify rsync to work in a half-duplex way.

I would obviously prefer to use rsync than tftp for all the other 
functionality that it provides. Does anyone have any suggestions on any 
other protocols that could do the trick?

Thanks in advance,

Adrian Cooke

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