Phone Calls Quality Issues

[Mike Paderna]

Issue: Call drops and calls cutting in and out using Cisco IP Phone 7841 and Cisco Wireless 7925G

Descriptions:  Client reported that since November 2016,  they are experiencing call drops in the middle of conversation and/or sometimes they are unable to pick the call (seems no one in the end of the line) and if they did calls, the line is horribly breaking up (calls cutting in and out).  Both network vendor and provider cleared any network connection issue.  We've submitted a lot of call samples to the phone vendor and found nothing wrong in the configurations.  We sent multiple techs onsite but found nothing's wrong even with the wifi connections..  The tech who went onsite suspected that it might be the Multi Link ACP device that connects to Cisco 2911K9 causes the issue but we set it aside because the client don't have any issues with the paging system, the music system, alarm system, nor fax machine function.  

The phone vendor suggested to our network vendor that this might be an MPLS issue.

Question:

1.  Can we still consider that the Multi Link ACP device has to do with it?

2. How MPLS affects the issue presented above?

3. Do you have any other suggestions what to check?

[Leo Laohoo]

sometimes they are unable to pick the call (seems no one in the end of the line) and if they did calls, the line is horribly breaking up (calls cutting in and out).  

Let me start by saying that I'm no phone guy.  I do wireless most of the time.  

I've seen something like this happening to 7925G.  But I need to know which one (land line or wireless) is unable to pick up calls?

The next question I'd like to ask is:  Is this occurring mostly with the 7925G?  So calling the land line to land line is fine?  And the issue is mostly happening to land line to 7925G?

[Mike Paderna]

Hi Leo,

The issue is for both the wireless and the landline phones.  I called the client using a landline phone.  The call was announced overhead the paging system.  Client picked the call up but immediately cut off (without any beep).  I called again and the client was able to pick the call using one of the wireless phones (wifi phone 1 - client have six 7925G) but the call is cutting in and out (but not disconnecting) even the client was near one of the  APs.  I advised the client to park or transfer the call to one of their 2 landlines but the call quality still the same.  I asked the client to park/transfer the call again in another wireless phone (wifi phone 5) but the issue remains.  The same happened when client received a call from a cellphone. 

Doing the outbound calls with the same workaround above, issue remains.