Is WMM enabled on an access point?

Capture and decode some streaming traffic with Wireshark. WMM or WME packets should be tagged and obvious.

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?

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?

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.

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

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.

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.

8440

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

Thanks. I couldn't find anything in the manual on the topic. However, I didn't have time to dig through all the docs.

Perhaps check if the firmware is the latest?

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?

A colleague assures me that this has been done.

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.

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

OK, that wasn't obvious. According to the "best practices" document at:

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.

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

OK, that sounds useful.

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.

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

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

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