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QoS values to match Lync-calls

A customer of ours is tuning QoS for Lync for better voice-quality. The wired network works fine, but on the wireless it looks like there are some “drops” from time to time.

The Lync-calls are tagged with AF41.

There are 4 types of QoS on the WLC. At the moment SSID is configured as Silver, but should it be Gold (instead of Silver) to match AF41?

Based on this document, Gold is AF41. Is that correct?

Is there anything else we could adjust and will they benefit from that QoS change?

Thank you!



Have you considered using AVC to mark the Lync application? If you're not sure what it is, check the links below:

Note the following prerequisites for AVC:

1. Available from WLC code 7.4

2. Not supported in Flexconnect local switching

If your client doesn't want to use AVC, you could also configure the QoS settings on the clients. For example for Windows 7, you have to go to gpedit.msc ---> Windows Settings---> Policy-based QoS

Thanks for the reply. All APs are in FlexConnect mode, so AVC is out of the question.

Rasika Nayanajith
VIP Mentor

Prior to configuration optimization, you need to ensure you have sufficient wireless coverage (20% overlap) & preferably clients are connecting in 5GHz band. This design guide cover most of topics (Voice, QoS, Multicast,etc) & read it thoroughly to see whether your wireless deployment adheres to those recommendation.

With respect to QoS here is my suggestions.

1. QoS profile to configured Platinum with 802.1p=6 (this will allow proper voice packets comes with 802.11e UP of 6 passthrough without capping the QoS value)

2. WMM (under WLAN -> QoS ) to be set as "Required" to avoid non-WMM traffic get prioratised.

3. If all local mode APs, you need to configure the QoS trust boundaries as below

- AP connected switchport : DSCP

- WLC connected switchoport : CoS

- inter switch trunks : DSCP

4. Makesure WLC management interface is not on native vlan (in otherwords on a tagged vlan) in order to proper QoS functionality.

5. If you are using AVC, better you mark up this traffic as EF, so your wired network will properly treat this traffic as Voice. Otherwiese this traffic will treat as video & will not get required priority within your network.

Additionally make sure priority queue "priority-queue out interface config" enabled for your access layer switchports. Below QoS guide help you to verify your switch QoS configuration, see whether you configured in inline with this guide recommendation



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I'll look into the documents you linked. Thank you very much for your answer.

If your APs are FlexConnect mode, then you have to trust COS, if you want to classify user traffic for QoS treatment based on the WLC QoS profile values you configured.

Refer below for detail



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