Christian Lamparter <chunkeey@xxxxxxxxxxxxxx> writes: > On Monday 07 December 2009 21:08:32 Kalle Valo wrote: > >> I don't know what time constraints you refer to here, but clients >> should stay awake until they have received a multicast/broadcast >> message with the moredata bit disabled. So, in theory, it doesn't >> matter even if the frames are transmitted even 20 ms after the beacon. >> (In practise some hardware might have timers for this, I think at >> least wl1251 had one.) > >> Of course the downside is the increased power consumption. But it's >> still better than to not receive the multicast/broadcast frames at >> all :) > > That's the thing: 802.11-2007 11.2.1.5 f) says: > "*Immediately* after every DTIM, the AP shall > transmit all buffered broadcast/multicast MSDUs...". > And I cannot rule out that some Devs took this quite literally. ;-) Well, "immediately" is relative. If my wife says to immeaditely do something, it might take a week before I'll do it ;) > Anyway, here is a case that I've witnessed: > > During testing, I caught samples where MC/BC frames were delayed for > more up to 115ms. (b_interval = 102.4ms and dtim_period = 3) Yeah, if the time is longer than the beacon interval then it won't definitely work. -- 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
