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Hi All,

running a packets capture, sometimes it happens to see some CF-END packets coming from Apple devices (frames with a correct FCS). This even if no PCF devices are on the market.Reading around it seems that this control frames can be used to reset the NAV counter after that the device have shoot a CTS-To-Self frame with an high duration (10ms).Some info are available here.
Have someone seen this behaviour an have a nice explanation?
thanksPietro

I'm not sure why the device is sending this frame, but the contention-free period is not specific to the PCF.  HCCA implements a controlled access phase, which is a CFP that can be instantiated at any time (rather than at a pre-defined time like with PCF).  Sounds like the device has implemented a few fancy features of 802.11e.