On 7 Jan 2013 09:35, "Michael Richardson" <mcr@sandelman.ca> wrote:
>
>
> I asked
>     > A comment was made a month ago or so about how long it takes wifi APs
>     > to switch from transmitting (unicast) to one station to another.  That
>     > there was quite a large latency here, and that this was one reason that
>     > the AP designers wanted large buffers to accmulate, so that the
>     > switching time could be amortized over a larger number of packets.
>
> Pedro Tumusok <pedro.tumusok@gmail.com> replied
>     > I might be way of here, but to me this sounds like a-mpdu which is
>     > used to aggregate frames to get higher throughput. Thats in the
>     > specification, its
>     > in 802.11ac and I believe that it go introduced with 802.11n.
>     >
>     > It is there to mitigate the overhead of aquiring the channel.
>
> Does this mean that 802.11a,b do not suffer from this problem?
>

They do not have that feature, but I assume they would still be bloated in other places for other reasons.

The a-mpdu got tweaked a bit in ac, to always use it. Even for single frames. Not only for aggregate as in n.