So before we can start testing, we need to ensure that the first two requirements in the WMM checklist are met. My current router, a D-Link DIR-655, has its WMM certification and its WMM enable is found on the Advanced Wireless settings page (Figure 2).
Figure 2: DIR-655 with WMM Enabled
Note that the DIR-655, and most of the D-Link router line, also has automatic QoS using Ubicom's StreamEngine technology. The 655 also has the wireless form of StreamEngine, known as WISH (Wireless LAN Intelligent Stream Handling). But neither of those has anything to do with WMM.
It's also easy to find wireless clients that are WMM Certified. All three notebooks that I used in my WMM testing had WMM Certified adapters: Intel PRO/Wireless 2915ABG;Intel WiFi Link 5100 AGN ; and Intel WiFi Link 5300 AGN.
Finding the WMM controls on the adapters is harder, however. The only WMM control that I could find was for AdHoc mode (Figure 2) on the 5100 AGN and 5300 AGN. And the 2915 AGN didn't even have that control.
Figure 2: WMM Ad Hoc control
But this Intel article says that WMM is enabled by default in the 2915 AGN. The 2915 AGN also supports an Intel Throughput Enhancement control for uplink throughput enhancement. But it is overridden if the adapter is associated with an AP that has WMM enabled.
The article also says that the Intel Throughput Enhancement control is supported in PROSet/Wireless Software 9.0 and later. So since all three adapters were running version 126.96.36.199, I guess that they all have WMM enabled by default.
However, it turns out that there is another switch that needs to be thrown to enable WMM. I have always been curious about the QoS Packet Scheduler in Windows XP and Vista that appears in the Network Connection properties of all network adapters (Figure 3). So I asked the Wi-Fi Alliance if it had to be enabled for WMM to work and they said yes. So make it so if you want WMM to work its magic.
Figure 3: Make sure the QoS Packet Scheduler is on for WMM
So that completes two of the WMM Checklist items. What about the third? It turns out that the story there is not so simple, so I'll save it for Part 2.