Is WMM enabled on an access point?

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Is it possible to tell without access to the configuration, if a given
access point supports WMM? Is there some flag checked in the packets sent,
or similar?

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Re: Is WMM enabled on an access point?
wrote:

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Capture and decode some streaming traffic with Wireshark.  WMM or WME
packets should be tagged and obvious.  
<http://www.smallnetbuilder.com/wireless/wireless-features/30837-does-wi-fi-multimedia-wmm-really-do-anything-part-3?start=2

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Re: Is WMM enabled on an access point?
Jeff Liebermann (for it is he) wrote:

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OK, so that's LAN side, but I can't do that until I actually get a
connection going. The problem I have is a fussy wireless client [Spectralink
SIP handset] that is refusing to see some access points that claim to have
WMM enabled, but the SIP phone is the only arbiter of WMM that I have. From
what I can tell, WMM interacts with DSCP and TOS at some level, so how could
a client refuse to connect to an SSID on the basis of no WMM, unless the
capability is advertised somehow?

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Re: Is WMM enabled on an access point?
alexd (for it is I) wrote:

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OK, I got it. Reading a Kismet dump file with Wireshark, drilling down into
a beacon packet, I see:

Tag: Vendor Specific: Microsof: WMM/WME: Parameter Element

and below that, the various WMM/WME properties of the packet. So that's how
it works. Now why couldn't I find that with Google?

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Re: Is WMM enabled on an access point?
wrote:

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Nope.  WMM is all on the LAN side.  Just connect your wireless device
to the router and sniff away.  No need for an internet connection to
see WMM and WME in action.
<http://en.wikipedia.org/wiki/Wireless_Multimedia_Extensions

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Spectralink was bought by Polycom in 2007.  Are you running some type
of antique?  A model number would be helpful.

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For most devices, there's nothing in the client that reeks of WMM or
WME.  WMM is just a sub-set of QoS, where the router classified the
type of traffic into 4 queues by categories, and rearranges the order
of packets by the most time sensitive packets to the least time
sensitive.  There's nothing the SIP phone needs to do to make this
happen as it's all in the router.

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To the best of my knowledge, there's nothing in the wireless
connection or authentication ritual that can be set to require WMM,
WME, QoS, or any other service.  That's because these and other such
services all are on Layer 3 (IP layer), while 802.11 wireless operates
on layer 2 (MAC layer).  However, DSCP is a layer 2 protocol, which
does it's QoS work at Layer 2.  There might be some such requirement,
but I haven't seen it.  TOS (Type of Service) is much the same as QoS
on Layer 3, except with 15 levels of service.  

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Re: Is WMM enabled on an access point?
Jeff Liebermann (for it is he) wrote:

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8440


Well, it may not need to, but it's choosing to in order to enforce 'best
practise', I guess.

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Re: Is WMM enabled on an access point?
wrote:

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Thanks.  I couldn't find anything in the manual on the topic. However,
I didn't have time to dig through all the docs.
<http://support.polycom.com/PolycomService/support/us/support/voice/wi-fi/spectralink_8400_wireless.html
Perhaps check if the firmware is the latest?  

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Well, make sure you have QoS for SIP enabled in the router, and it
should stop complaining.  Look for how ports 5060-5063 (for 4 lines)
is handled.

Ummm... make and model of router?

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Re: Is WMM enabled on an access point?
Jeff Liebermann (for it is he) wrote:

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A colleague assures me that this has been done.

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I'm not sure I've made myself clear. The handset won't acknowledge the
existence of the SSID, so we're not even at the point where it could get
connected to complain about anything. I am under the impression that the
mechanism by which it discriminates is WMM, and the reasoning is not so much
QoS as battery life.

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Well, it's a Linksys L3 switch between the wireless LAN and the phone
system. No WAN router involved. APs are Ubiquiti Unifi.

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Re: Is WMM enabled on an access point?
wrote:

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OK, that wasn't obvious.  According to the "best practices" document
at:
<http://www.polycom.com/global/documents/products/voice/datasheets/best-practices-for-deploying-plcm-spectralink-8400.pdf
it supports all the encryption and authentication protocols possible.
Perhaps the Ubiquiti AP is set to only accept 802.11b?  Perhaps the
Ubiquiti AP has SSID hiding enabled?  Lot's of possibilities.  

See the section on QoS on Pg 23.  My guess(tm) is that you have WMM
Admission Control enabled on the handset.  See Pg 25.  It is disabled
by default, but worth checking.

I suggest you find another AP that can be used for tinkering, and see
what the 8440 can do talking to it.  If that works, then the problem
is probably in the Ubiquiti AP settings.  The Unifi AP comes with
diagnostics that might help.  I don't have any experience with it.
<http://www.ubnt.com/unifi

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Possibly.  WMM is used to save battery power.  I usually turn it off
because it tends to create a start up delay.

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Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: Is WMM enabled on an access point?
Jeff Liebermann (for it is he) wrote:

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OK, that sounds useful.

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Works fine with a Ruckus AP [they're on the approved list], but only if WPA2
isn't in use. Grr. As the WLAN is already deployed and predates the phone,
and nobody is interested in supporting the phone if it's not used with a
whitelisted access point, I'm minded to sling the phone and use a different
one.

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Re: Is WMM enabled on an access point?
Jeff Liebermann (for it is he) wrote:

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I've narrowed it down to WMM power saving, which it looks like the Unifi UAP
doesn't support:

http://forum.ubnt.com/showthread.php?p=210231

Although someone else says it does, perhaps just reading "WMM" and not
noticing the UAPSD bit:

http://forum.ubnt.com/showthread.php?t=42386

Unless of course UAPSD is an integral part of WMM, in which case it doesn't
really support WMM.

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