Modify tunnel.py to supprot usrp2

Hello,

When I modified the code of tunnel.py, I met a problem. I want to direct
use the eth0 interface, not add a gr0. But there was no device,
/dev/eth0, dose anybody has the experience.

Can I open eht0??

BTW, dose anybody know the relationship between BER and sensitivity.
The word, sensitivity, comes from iwconfig command.

Thank for your help. :slight_smile: