In wireless networking, for power efficiency the access point(AP) sends a beacon to inform the client of pending packets periodically and the client only wakes up every beacon interval (e.g. 100msec) to listen to beacons.

However, a client have no idea about the specific time when a beacon arrives. How does it know when to wake up and get the beacon?

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1 Answer 1


Beacon frames contain timestamps which the client uses to update its clock. Technically it does know when a beacon arrives due to this.

A client is expected to wake up and listen to a minimum of one beacon when the listening time is up.


  • @HyZhang this has a lot of detail backing up APA's answer too. Aug 10, 2015 at 14:44

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