PC + Softphone over WLAN QoS

Question

I could not find after hours of searching what Cisco’s best practice when using a PC and softphone in a wireless environment.
We have always had wireless phones in one WLAN (platinum) and PC in another WLAN (silver). But now we have PC + Softphone scenario which is growing
Do we now put all PC's into the voice WLAN (hundreds of users) which is setup as Platinum and mark the voice traffic from the softphone DSCP 46 (maybe 48 because of WMM and COS mapping) and everything else from PC mark as best effort?
If WMM is turned off on the PC will the AP then treat all traffic as Platinum level regardless of DSCP marking.
If I leave the users in the Silver WLAN then all traffic will get marked down to best effort.This is current setup and voice quality is suffering.
I don’t feel comfortable putting hundreds of users on a Platinum level WLAN but how else can I prioritize softphone voice traffic. What are the implications of putting pc + softphone users into the voice wlan? What does cisco recommended for this scenario?
if you have any insight/experience/documents please let me know
Thanks!

Answer 1

steve sousa wrote:Do we now put all PC's into the voice WLAN (hundreds of users) which is setup as Platinum and mark the voice traffic from the softphone DSCP 46 (maybe 48 because of WMM and COS mapping) and everything else from PC mark as best effort?If WMM is turned off on the PC will the AP then treat all traffic as Platinum level regardless of DSCP marking.
WLC does not do anything to the QoS on the packets it forwards except the translation between 802.11e ot 802.11p.
If you have clinets that are connected to a Platinium profile but they use normal DSCP (data. No priority) the traffic will be treated normally as data with no priority.
If another WMM enabled client connected to the same WLAN and send voice traffic with platinum profile, the traffic will be mapped to the appropriate 802.1p and will pass the wire with priority.
The controller does not apply its own QoS. The QoS support on the WLC gives the WLC the ability to apply the same priority that is set on the wire (or application).Therefore, the only action a WLC or AP will do is copy the value of the original packet to the outer header of the LWAPP packet. The whole purpose of the gold, silver, and bronze QoS options on the WLC is to perform proper QoS translations between 802.11e/802.1p UP values and IP DSCP values, which depend on the application or standard that is used. Once again, QoS on the WLC ensures that packets receive the proper QoS handling from end to end. The controller does not perform its own QoS behavior. The support is there for the controller to follow suit if QoS already exists and priority needs to be applied to wireless packets.You cannot have QoS only exist on the controller.
Reference: http://www.cisco.com/en/US/tech/tk722/tk809/technologies_configuration_example09186a00807e9717.shtml
Also;
Note WLAN client support for WMM does not mean that the client traffic automatically benefits from WMM. The applications looking for the benefits of WMM assign an appropriate priority classification to their traffic, and the operating system needs to pass that classification to the WLAN interface. In purpose-built devices, such as VoWLAN handsets, this is done as part of the design. However, if implementing on a general purpose platform such as a PC, application traffic classification and OS support must be implemented before the WMM features can be used to good effect.
Reference: http://www.cisco.com/en/US/docs/solutions/Enterprise/Mobility/emob41dg/ch5_QoS.html#wp1021909
HTH
Amjad