Jouni Malinen <j@xxxxx> writes: > On Fri, Nov 09, 2007 at 11:52:30AM +0100, Johannes Berg wrote: > >> Something I'm not clear on right now is the timing of it all. If there >> are say two BSSes, the driver can simply program the hardware to half >> the beacon period and then the beacons will alternate. But if there are >> seven BSSes, the beacon period might not be divisible by seven so timing >> errors will happen and, worse yet, accumulate. Does hostapd somehow >> account for this? Or should the beaconing work completely differently, >> for example with all N beacons sent in a burst? > > You could always modify the beacon period to a suitable number that > would be divisible by whatever number of BSSes there are and/or add > empty slot to move from, say, 7 to 8, and just not send a beacon at some > of the slots. Sending a burst of all beacons at the same time is also a > valid option up to a certain limit on how long a time would be allocated > for this. However, this may have some timing issues when there are > multiple power save buffered broadcast/multicast frames waiting to be > sent out. In general, it would be good to try to send the beacon frames > as close to their correct time as possible to allow power saving > stations to remain asleep most of the time. Exactly, it is important for small mobile devices that beacons are sent at the correct time. For example, I have seen broken APs which Target Beacon Transmission Time fluctuates and Nokia N800 has high power consumption because of that. -- Kalle Valo - To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
