Wireless Access

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Occasional Contributor II
Posts: 14
Registered: ‎10-19-2012

UCC Call Quality

Hi, we recently upgraded to Aruba 7220 controllers.  After backing up and restoring the settings to the new controllers, and upgrading the software , we were getting calls of reduced call quality with Voip Phones (Voalte).  We had concerns that maybe the upgrade was not ideal for our older AP's (105's) so we reverted back to the older software (6.4.3.8).  

 

What we see in the UCC reporting is that WLAN call quality is averaging fair, but End to End call quality is reported as good.  Before the controller upgrade, all UCC calls were rating in the Good range, for both WLAN, and End to end.  

 

Is our best bet to start over with the documentation for configuring a Voip SSID, or does the fact that WLAN quality rates fair, while End to End rates good, indicate specific settings that we should review in the configuration?  

 

thanks,

Dave

Guru Elite
Posts: 21,513
Registered: ‎03-29-2007

Re: UCC Call Quality

Questions:

 

- Do the Voalte phones do WMM?

- Are you using encryption?

- Are you configured for end-to-end QOS?



Colin Joseph
Aruba Customer Engineering

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Occasional Contributor II
Posts: 14
Registered: ‎10-19-2012

Re: UCC Call Quality

The phones are Spectralink 8742's working with voalte software.  They support WMM and DSCP tagging.  The SSID they are on is using WPA2-AES.  We are reviewing the end to end QoS but do believe we had it configured properly before the move to the new controllers, as all UCC scores were in the Good range for both WLAN and End to End.  

 

 In the UCC details from the controller, we see that the Client WMM AC is 6, and the client DSCP is 46.  

 

thanks,

Dave

Guru Elite
Posts: 21,513
Registered: ‎03-29-2007

Re: UCC Call Quality

Can you do an over-the-air packet capture of a call?  If you do, you should be able to open the capture in wireshark and use the filter  wlan.qos.priority == 6 to see if the client traffic is being properly prioritized in both directions over the air.

 



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Guru Elite
Posts: 21,513
Registered: ‎03-29-2007

Re: UCC Call Quality

Honestly, the main thing that matters in VOIP and Video QOS is that the traffic is properly prioritized between the client and the AP.  That is because between the client and the AP over wireless is the main place that contention occurs in a shared medium and QOS is mandatory so that voip traffic is not degraded by other traffic. The client is responsible for tagging traffic from the client to the AP and the AP is responsible for tagging traffic from the AP to the client.  Others make a big deal about QOS on the wired network, but quite frankly, most wired networks have little to no contention.  The main place where contention would occur on the wired network is on a WAN or oversubscribed link where VOIP traffic would need to be prioritized.

 

Making sure that the wireless QOS is in place using an over the air wireless pcap is the easiest way to ensure that your configuration is correct.



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Guru Elite
Posts: 21,513
Registered: ‎03-29-2007

Re: UCC Call Quality

Here is an example:

priority.png

priority2.png



Colin Joseph
Aruba Customer Engineering

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Occasional Contributor II
Posts: 14
Registered: ‎10-19-2012

Re: UCC Call Quality

Thanks we can look at that, so are you saying that the UCC reporting from the controller may be wrong in saying that the Client WMM AC for these calls is 6, and we may see something different within the packet capture?  

 

If the Pcap looks correct, then we need to go back over the config to make sure Voip specific settings are set as to what Aruba recommends? 

 

thanks,

Dave

Guru Elite
Posts: 21,513
Registered: ‎03-29-2007

Re: UCC Call Quality

I am saying that the packet capture is definitive.  The controller indicates QOS in a few locations and I do not know where you are looking to say whether or not QOS is occurring in both directions.  If you can do a wireless packet capture, you can determine if it is happening or not, without reviewing alot of settings.



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor II
Posts: 14
Registered: ‎10-19-2012

Re: UCC Call Quality

I do see the Qos Control Priority set to 6 in captured packets to and from the phone I was testing with.  I am going to see if Spectralink has any recommended settings that maybe we are not using currently for this SSID.  The drop in UCC quality coincides with the move to the new controllers, not sure if the migration, or the upgrade of code on the new controllers may have caused some change to a setting we are missing.  

 

thanks,

Dave

Guru Elite
Posts: 21,513
Registered: ‎03-29-2007

Re: UCC Call Quality

While the call is in progress, you can also type "show datapath session table <ip address of phone>" to see if the traffic is prioritized in the datapath as well.  The drop in voice quality could very well be an anomaly.  You would have to compare the phone to phone to determine if that is the case.  Now that you have checked the packet captures and the phone is doing what it should, the next thing we should check is the RF...

 

What encryption is that SSID using?

Did you remove any rates on that SSID?

What is the minimum and maximum transmit power of your access points on that band in the ARM profile?

What band are the spectralink phones using?

Do you have "Drop Broadcast and Multicast" enabled on all of your Virtual APS?



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

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