lwip on half duplex media

Hi

The lwip distrubutable uses an Ethernet controller.

I suppose that it's possible to run lwip on top of a another physical layer, e.g. a proprietary radio link between two computers ??

There is a problem is related to the fact that the radio link is half duplex. This problem can be addressed by two methods:

- Ignore it. There will be collisioins. The TCP layer will retransmit, but the UDP layer will not.

- Add a link layer below IP which will carry packets betweeen the two computers. This link layer will also handle retransmissions. This layer can be e.g. HDLC ?

Any good ideas?