On 2/20/08, Sam Leffler <sam@xxxxxxxxx> wrote: > Tomas Winkler wrote: > > On Feb 20, 2008 5:24 PM, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote: > > > >> Hi, > >> > >> I've long thought about implementing APSD but it seems to require > >> setting the "more data" bit in an ACK frame and various other things. > >> Ron, I think you're the QoS expert, is that really how APSD works? If > >> so, does iwl firmware implement that? > >> > > > > We have uAPSD implementation, mainly AP part, yet again it for older > > mac. It will take a bit time to merge it in > > It's a mandatory feature for HT AP. > > > > Really? Can you point where that's called out in the spec? You can not get WFA 11n certification without getting first WMM-uAPSD certification. 4965AGN uCode image supports uAPSD in client mode (and certified under Windows). uAPSD in AP mode is under developement currently. > > > >> Also, does Atheros hardware implement that, and how? It doesn't look > >> like Broadcom firmware implements it, and I don't really understand how > >> one could implement it without many hardware queues, since it seems > >> timing critical to send out the frames to the station that is using > >> APSD. > >> > >> > > Don't believe it's possible to that without HW support. > > > > Sorry, this is incorrect; you can do UAPSD w/o any special h/w support. > > Sam I think you may do uAPSD client mode w/o special HW/FW support (though it won't be optimized), but definitelly not AP mode - you need some RT capabilites for tracking the client state (wake/sleep/doze) and stop sending frames to a client that entered a sleep state, need to avoid out-of-order transmission when rescheduling frames that were dropped because a client entered sleep/doze state, Service Period control, etc. > - > 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 > - 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
