The radio model describes the physical device that is capable of transmitting and receiving signals on the medium. It contains an antenna model, a transmitter model, a receiver model, and an energy consumer model.

The medium model describes the shared physical medium where communication takes place. It keeps track of radios, noise sources, ongoing transmissions, background noise, and other ongoing noises. The medium computes when, where and how transmissions and noises arrive at receivers. It also efficiently provides the set of interfering transmissions and noises for the receivers.