QoS on WiFi

[Joe Bloggs]

Hi,

I've got a WLC and a number of LWAP's configured on my network. My Skype users want to be able to use voice & video.

The application is marking the DSCP values for Voice and Video. 

Now how do i get the WiFi infrastructure to honour these markings and apply typical QoS control?

I understand that WiFi QoS works a little differently to Wired, basically it is working at Layer 2. However it isn't CoS based either. So this is confusing me somewhat.

My limited understanding of the WLC documentation seems to indicated that you can extend the QoS trust boundary on a WLAN but can only control one type of traffic. Is this correct?

So effectively you can apply a QoS profile "Platinum" for Voice for example on a WLAN or "Gold" for Video say , but not both together. 

So my question is can you configure a Single WLAN to honour DSCP for Voice, but if it is a Video call honour and control DSCP for Video as well? Or does everything else fall into Best efforts?

Thanks in advance

[Rasika Nayanajith · Accepted solution]

Hi Gavin,

You have to consider upstream & downstream separately & implement QoS keeping that in mind.

Now how do i get the WiFi infrastructure to honour these markings and apply typical QoS control?

You need to trust DSCP on switchports connect to your APs & WLC. Pls go through below ciscolive presentation to get good grasp of wireless QoS

BRKRST-2515 QoS Design & Deployment for Wireless LAN

My limited understanding of the WLC documentation seems to indicated that you can extend the QoS trust boundary on a WLAN but can only control one type of traffic. Is this correct?

Not correct. Those QoS profile (platinum, gold,etc) set maximum DSCP value it will allow on a SSID. So best to keep it Platinum so it will allow upto DSCP 46 traffic without capping DSCP value.

So my question is can you configure a Single WLAN to honour DSCP for Voice, but if it is a Video call honour and control DSCP for Video as well? Or does everything else fall into Best efforts?

Yes, once you configure WLAN with "Platinum Profile" it will honor voice, video & other DSCP values. Not treating all other traffic (except voice) as best effort.

HTH

Rasika

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[Joe Bloggs]

Thanks for the reply.

This clears it up nicely.