Two network cards in same sysem

My UDP test tool based on socket ,client and server running on same system , but i need them communication in physical layer instead of logical layer by windows.

 

Sorry but I'm not sure exactly what you want to do. Could you explain more?

 

Thanks very much.
I write a network test tool, and there are two network cards in my system, the client bind to the first network card and server bind to the second network card, now client begin send data to server, the data will be send in logical layer because system find the both IP in same system, but I need the data be sent across the network card.
It looks like the "useloopback = 0" environment parameter in UNIX.