Wednesday, November 13, 2013

Bad VoIP Call Quality

Sometimes voice can be a little hard to troubleshoot.  We had a remote site (out of over 700 sites) that reported bad call quality.  So, as I started looking at this, I couldnt really pin point this issue.  So, lets look at the symptoms:
1.  Does the bad call quality happen all the time?  No.
2.  Does the bad call quality happen from inside only inside the branch (from one phone to another, only inside this branch)?  Yes (however, the real truth was No)  Sometimes you have to ask multiple people.
3.  Does the bad call quality happen from one branch to another branch?  Yes.
4.  Dos the bad call quality happen when the call is outside the company?  Yes.
So, after reviewing the switch and router configs at the remote site, the QoS configs look good.  Plus, I dont see any dropped packets in the 'show policy" command for the voice packets (although I did for the default class, like Internet, etc).  CUCM regions, etc look good.
So one of the data guys on the team looked into what the MPLS carrier's QoS policy for us was for our voice.  384k for 30 users.  On our router, we have a priority for 25% for the 3 bonded T1s (4.5 Meg).  So, we have 1.1 Meg dedicated for voice on our router.  So, he up'ed our QoS at the carrier and things look much better.  When they drop packets for you (lol), I guess the voice is going to sound bad. :)  Anyway, problem solved.


  1. I think its depend upon your quality of work that how are you provide services on voip then decide what will be your call quality.........

    1. Im not sure what your point is here, but this was solely an ISP problem. I described the SLA problem, and that did resolve the issue we had. Nothing done in our network at all. The only changes that were made was QoS settings in the ISP.


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