[Bloat] [Cerowrt-devel] uplink bufferbloat and scheduling problems
David Lang
david at lang.hm
Thu Dec 2 04:09:49 EST 2021
On Thu, 2 Dec 2021, Toke Høiland-Jørgensen wrote:
> "Valdis Klētnieks" <valdis.kletnieks at vt.edu> writes:
>
>> On Wed, 01 Dec 2021 13:09:46 -0800, David Lang said:
>>
>>> with wifi where you can transmit multiple packets in one airtime slot, you need
>>> enough buffer to handle the entire burst.
>>
>> OK, I'll bite... roughly how many min-sized or max-sized packets can you fit
>> into one slot?
>
> On 802.11n, 64kB; on 802.11ac, 4MB(!); on 802.11ax, no idea - the same as 802.11ac?
As I understnad it, 802.11ax can do 16MB (4MB to each of 4 different endpoints)
This is made significantly messier because the headers for each transmission are
sent at FAR slower rates than the data can be, so if you send a single 64 byte
packet in a timeslot that could send 4/16MB, it's not a matter of taking
1/128,000 of the time (the ratio of the data), it's more like 1/2 of the
time.
So it's really valuable for overall throughput to fill those transmit slots
rather than having the data trickle out over many slots.
David Lang
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