On Tue, Sep 27, 2011 at 3:39 PM, Luis R. Rodriguez <mcgrof@xxxxxxxxx> wrote: > On Tue, Sep 27, 2011 at 1:49 AM, Ashok Nagarajan <anagar6@xxxxxxx> wrote: >> In our previous conversation, Thomas was mentioning about very low >> 802.11n rate and we din't have a clear reason for such low 11n rate! > > This may be WMM not being configured which is required for 802.11n, if > you disable WMM on the AP <--> STA setup you may see the same poor > performance. So this is due to the fact that 802.11e which WMM requires is the component of the spec that adds BlockAck support and therefore Aggregation. You'll achieve higher throughput once you support aggregation. I just reviewed with Thomas how we'd go about setting WMM parameters and it seems we want to do this in cfg80211 at set channel. This also bring up the question for IBSS as well and what to do when your peer has different WMM parameters, this is not something you deal with with infrastructure mode. For now I would go with using default WMM parameters which the spec does specify for both IBSS and Mesh and not peering up unless your peer also beacons those same parameters. Later we can figure out how we want to handle differences, maybe go with the minimum? The difficulty with converging to values is although likely possible you can also end up with races with different nodes on your network trying to sych up with the same values. For example, for IBSS we've already learned that if you do not want an IBSS merge split you want to ensure to use the same SSID and BSSID. I cannot be sure right now that any sort of similar splits may happen with WMM / HT settings but just want to put that thought out there before we support it. If we only support peering up with peers with the same WMM capabilities at least we will not introduce issues, only limitations with peers which can later be addressed if it addresses properly all known mismatch issues. Thomas is now looking at adding the WMM stuff for Mesh, the same will be required for IBSS HT support. A while back we had heard 802.11s support will *not* support aggregation, Javier, did the spec go out like that? Why was aggregation thought to not be possible with 802.11s? I can't see why right now. If we want to do comparable throughput tests for HT rates with Mesh we'd need to setup an AP with aggregation disabled, and the same WMM parameters. Luis -- 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
