WLC 5508, Prime Infrastructure, 7921 phones and QoS

[Sergey Balyura]

Hi everybody!

I have deployed about 50 wireless cisco phones int the network with 27 APs with the WLC 5508.

I'm trying to investigate phones behaviour (I have some loss of audio).

And I use Prime Infrastructure for monitoring.

I run the Voice Diagnostic on the selected two phones.

and in the Charts I see the next:

1. for one phone "Downlink AC Queue Usage" shows all the traffic of "voice packets". but "Uplink AC Queue Usage" shows all the traffic of the "Best efforts packets".

2. for the second phone "Downlink AC Queue Usage" shows all the traffic of "Best efforts packets". and "Uplink AC Queue Usage" shows all the traffic of the "Video packets".

that is strange, very strange. the WLAN of these phones uses platinum QoS. none of other WLANs uses "gold" QoS.

does this mean I have a QoS misconfiguration?

where may the failure be? WLC? switches? router?

please, any suggestions...

[Rasika Nayanajith]

Have you configured QoS end to end (AP connected switch ports, WLC connected switchports, ect), It is much more than setting QoS profile in WLAN. What is "show qos platinum" output of your WLC, does it correctly set dot1p value to 6.

(WLC) >show qos platinum

Description...................................... For Voice Applications

Maximum Priority................................. voice

Unicast Default Priority......................... voice

Multicast Default Priority....................... video

.

.

.

protocol......................................... dot1p

dot1p............................................ 6

Post AP conected switch port config & WLC connected switchport config to review.

This link should be help you to understand this little better.

http://mrncciew.com/2012/11/28/understanding-wireless-qos-part-1/

HTH

Rasika

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[Sergey Balyura]

hello, Rasika!

thanx for your answer.

I have already configured switch ports towards APs as  trunk and "mls qos trust dscp"

And I have already configured the switch port towards WLC as trunk and "mls qos trust dscp"

Now I have a very strange thing.

I interconnect two my wireless phones.

in charts of voice diagnostic (in Prime Infrastructure) I see that two phones receive and send voice packets.

but on TSM charts I see the the most traffic use "fair" QoS. does it mean my QoS is misconfigured? if so where can I check it?

and int rhe Problem part of diagnostic page I see a lot of "Fair Downstream packet delay".. is it another consequance of the same problem?

please, help me. don't know what to look at

[Rasika Nayanajith]

I noticed few misconfigurations as per your response

1. Are you configured AP as FlexConnect ?  If not AP connected switchport should be configured as ACCESS port & trust DSCP. If it is configured as FlexConnect, then you can configure switchport as turnk & in that case you  have to trust CoS using "mls qos trusct cos" command.

2. WLC connected trunk ports always to be configured to trust CoS not DSCP. Otherwise WLC set QoS value ignored by your switch.

3. If you WLAN is set for Platinum then you have to configure Platinum QoS profile for 802.1p & set value as 6.

I would suggest you to verify QoS value preserve across you switch network. You have to take some wireshark packet caputres (as shown in my reference link) and make sure your voice packet DSCP goes into rest of your network as EF. You need to do this for upstream & downstream (from 7921 perspective) traffic. Here is the traffic flow if AP connected to switchport 1 & WLC connnected to switchport 2.

7921 <-> AP <-> Switch port 1 <->  Switchport 2 <->  WLC <-> Switchport2 <-> Rest of your network

Once you do this, then you can go to Prime & check those charts to reflect QoS values correctly. Otherwise you do not know where these QoS value get stripped/or modified in your network.

HTH

Rasika

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