The whole point here is that DBA is used to control the start of the
slot times, and SWBA is used to only send out actual beacon frames in
multiples of that.
normally you'd have SWBA be just before DBA, and and they'd have the
Here DBA is used primarily to gate the start of the slot time for that
particular device, and it only bothers sending the beacon frame every
'tdmaswba' DBA intervals. The beacons are used to announce that the
device is there and to update RTT estimates; it's not doing anything
like gating broadcast traffic.
On 18 February 2015 at 09:55, 子文 <u...@163.com> wrote:
> Dear Adrian
> In HAL_INT_SWBA handler of ath_intr funtion . What means tdmaswba? I found
> the tdmaswba default is five and when it decrease to zero ,the ap will send
> out the beacon package. From here I fell every SWBA is the start of the slot?
> 在 2015-02-19 01:28:38，"Adrian Chadd" <adr...@freebsd.org> 写道：
>>DBA gates the actual beacon transmit - if there's no beacon in the
>>slot, then it's fine.
>>SWBA is the software timer that fires just before DBA, so the software
>>stack has a chance to program the hardware with a beacon and let the
>>hardware get the packet DMA -> TX FIFO setup all correctly so that
>>when it's DBA time (ie, time to /transmit/ the beacon), it's already
>>ready to go.
>>On 18 February 2015 at 09:09, bh <u...@163.com> wrote:
>>> Dear Adrian
>>> In ath_intr , there are a variable which decrease every swba, so when
>>> the variable swbaintalval is zero, ap will send beacon .So I think the
>>> period of swba is slot time, ap will send beacon every five slot, the
>>> beacon interval is five slottime?
>>> Adrian Chadd <adr...@freebsd.org>编写：
>>>>On 18 February 2015 at 07:55, bh <u...@163.com> wrote:
>>>>> The default slotcnt=2 , becntival=5.For ap it will generate SWBA
>>>>> every slot,it will send beacon every five slots, beacause ap fire the
>>>>> DBA timer in every slot, so it will send data package in every slot. Is
>>>>> my above understanding correct?
>>>>It generates SWBA every beacon interval, which is calculated in
>>>>Master stations beacon 20 times a second with the default config
>>>>specified by the wiki.
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