Date: Sat, 20 Feb 2010 13:55:53 -0800 From: Sam Leffler <sam@errno.com> To: Alexander Egorenkov <egorenar@googlemail.com> Cc: freebsd-net@freebsd.org Subject: Re: Missing WME information element causes problems with 802.11n Message-ID: <4B805A69.7030004@errno.com> In-Reply-To: <2d3b7e441002181058u5006595an5c636843945bcca7@mail.gmail.com> References: <2d3b7e441002181058u5006595an5c636843945bcca7@mail.gmail.com>
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Alexander Egorenkov wrote: > I have encountered a problem with a 802.11n router Belkin F5D8631au. > The beacon and association response frames sent by this router do not > contain > WME information element although 802.11n mode is enabled. These frames > contain > HT capability IE and HT info. Because WME IE is missing in association > responses, > the net80211 stack does not set IEEE80211_NODE_QOS flag > (See ieee80211_sta.c:sta_recv_mgmt:IEEE80211_FC0_SUBTYPE_ASSOC_RESP). > But the flag IEEE80211_NODE_HT is set because the frame contains HT > capability and HT info. > > So, because IEEE80211_NODE_QOS is not set, all outgoing DATA frames sent to > the Belkin AP > do not contain QoS field in the 802.11 frame header. And it causes problems > with the Belkin AP. > > Is the QoS not mandatory for 802.11n mode ? > Why is QoS enabled only if an WME IE is found in association response ? > Would it be not right to enable QoS also if HT mode is enabled but no WME IE > was found ? The WME ie is mandatory; these routers are non compliant. We can probably hack net80211 to auto-enable WME if an HTCAP ie is present but that is a total hack. Were the HT ie's using the IEEE codes or the Vendor OUI codes? It could be this is old Broadcom code--at one point Broadcom intentionally didn't advertise WME. If this is the legacy HT stuff then perhaps we can add the auto-enable conditional on the legacy HT support. Sam
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