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= Scheduler =

The MAC High Framework has the ability to allow an upper-level MAC to schedule the execution of an arbitrary function at some point in the future. Schedules are broken up into two broad categories: coarse and fine. The coarse scheduler can be used to schedule events with an accuracy of  + or - 100ms, while the fine scheduler can be used to schedule events with an accuracy of + or - 100µs. The use of the fine schedule does increase the workload of the processor as it has to poll the scheduled events more often.

== Example uses of scheduler ==

=== Periodic Beacon Transmissions in the Access Point Upper-level MAC ===

The AP implementation periodically transmits a beacon MPDU. It uses the scheduler to periodically call its own function that creates and submits a beacon MPDU to the transmit queue.

=== Timeout during Active Scan process in the Station Upper-level MAC ===

When performing an active scan to look for nearby access points, the station implementation transmits a probe request followed by waiting for probe responses. This wait is implemented via the scheduler. When the scheduler calls the registered callback, the station implementation jumps to a new channel to continue the process.

=== Local Traffic Generation in the MAC High Framework ===

Internally, the [wiki:../LTG Local Traffic Generator] uses the same scheduler to generate different traffic patterns.