T ~ ~ ~ T [A] [B]_____[C]

Imagine three computers: A, B, and C. A and B both have radio equipment and can communicate via the airwaves using a suitable network protocol (such as IEEE 802.11). B and C are connected via a cable, using it to exchange data (again, with the help of a protocol, for example Point-to-Point Protocol). However, neither of these two protocols will be able to transport information from A to C, because these computers are