Medium access control

All practical communications devices share a medium, even a point-to-point connection, and medium access control (MAC) techniques are the means by which sharing is possible. Applications include local area networks both wired and wireless, longer-ranged wireless networks such as cellular telephony and military tactical radio communications, and long-haul resources such as satellites and optical networks.

Methods include reservation, contention, and token-based. A reservation method reserves some resource, such as a time slot relative to the start of a cycle of communications, a frequency within a shared part of the electromagnetic spectrum, or a physical connection within an interconnection fabric.