Contention free pollable

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Contention-free pollable (CF-Pollable) is a wireless computer networking standard defined by the IEEE 802.11b standard. It uses CSMA/CA or carrier sense multiple access with collision avoidance. CSMA is a contention-based protocol which makes certain that all stations first sense the medium before transmission. CA stands for Collision Avoidance, whereby each device on a wireless network sends out a signal, a request to send, then waits for a 'Clear to Send' reply from other devices on the network before broadcasting information.

In one way of implementing CSMA/CA, the access point polls each device on the network incrementally, providing a Clear to Send window. This is useful when transmitting audio or video streams because of the strict synchronization provided.