• Note: The Power Management bit is used by the client STA to indicate that it's going INTO or coming OUT OF Power Save mode. 0 = Active Mode, 1 = Power Save mode.

    Answer: Correct, a client STA that is acting acting accordance with the standard SHOULD NOT be flipping this bit constantly unless it is for off-channel scanning purposes (which is only done every so often). Unfortunately, Atheros (and possibly others) have decided that it's not really violating the standard to go into and out of PS mode rather than to stay in PS mode and to following the PS-Polling routines. Neither way is more power efficient really. This "end-run" around the standard is just another way of accomplishing the same thing.

    Note: Atheros AR5001X+ chipset cards (don't know about all of the rest), do this thing where instead of staying in PS mode, look for their AID in the TIM, the do PS-Polling, they flip the PM bit to 1, wait a VERY short time, and then flip it back to 0 (which will cause the AP to flood all queued frames). This process of flipping back to 0 is done arbitrarily and does NOT take into account what the client STA sees in the TIM about its own AID - trust me, I've checked that out.

    Answer: Correct again. Modifying a client STA's performance vs. battery life slider will change the listen interval (802.11-1999, R2003, section and the DTIM Interval it's using to awaken itself after dozing.


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