What is DCF (Distributed coordination function)?

Distributed coordination function is the medium access control (MAC) procedure. DCF utilizes carrier-sense multiple access with collision avoidance (CSMA/CA) with binary exponential backoff algorithm.
The Distributed Coordination Function frames the premise of standard Carrier Sensing Multiple Access / Collision Avoidance access within an 802.11 network. The DCF first verifies whether the radio connection is free prior to send and to avoid contention, starts an irregular backoff. The DCF might utilize the Request To Send and Clear To Send strategy to additionally prevent collisions.