In our QoS testing, we discovered that both the client and AP are using an incorrect WMM AC to transmit voice packets.
We use Jabber, and we adhere to the recommended Cisco values for DSCP:
Voice: 46 (0x2E, EF)
Video: 34 (0x22, AF41)
So, on our SSID profile, we set the DSCP mapping for WMM Voice as 46 and Video as 34.
However, a decrypted wireless packet capture on our PSK SSID revealed that both the client and AP are marking the 802.11 layer 2 header as priority 5 (Video) when we expected it to set it as 6 or 7 (Voice). In the IP header we see that the DSCP value was indeed 46.
My colleague found this page from the user guide ( http://goo.gl/wpOcPF ), which talks about using an ACL to set the dot1p priority so that the AP will use the Voice AC, so that would work fine from the AP to the client. But what about client transmission settings? Does anyone out there know how to influence clients such as Windows and Mac to mark the layer 2 header according to Cisco's preferred DSCP values? Our Jabber guy seems to indicate that that is not configurable on his end. It sounds to me like it's an OS or driver thing.
We use AD group policy and JAMF, if that helps.