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Troubleshooting intermittently dropped calls RRS feed

  • Question

  • We are experiencing intermittent dropped inbound and outbound calls.  How do I go about troubleshooting this to get at the root cause?  Telephony is currently provided through direct SIP trunks to Broadvox.

    Wednesday, December 7, 2011 6:02 PM

Answers

  • The answer is to edit the MediationServerSvc.exe.config file and add the following;

    <appSettings>
          <add key="GatewayIgnoreMediaTimeout" value="True" />
    </appSettings>

    • Marked as answer by Noya Lau Wednesday, December 14, 2011 9:49 AM
    Tuesday, December 13, 2011 11:05 PM

All replies

  • We had similar problems and invested a great deal of effort investigating that proved fruitless.  Finally, we removed Trend antivirus from the Lync servers and the problem was largely, if not entirely, solved.

    Wednesday, December 7, 2011 11:30 PM
  • Hi,

    i do not see tha Broadvox in Remommended list to work directly with the Lync Server. you might face these type of issues if you try to use non recommended setups. but to drill down further, tou can start with the SIP Trunk availability monitoring by using a tool such as Alchemi Eye and if you can run a bandwidth monitor on the mediation server to check whether if there's any packet loss, that's also great.

    Further more, deploy the Monitoring server reports. you can get an idea of what really happened when you experiace a dropped call by looking at the report.

     


    Thamara. MCTS, MCITP Ent Admin, Specialized in U.C Voice OCS 2007 R2
    Thursday, December 8, 2011 3:05 AM
  • Broadvox internally supports Lync however they have not gone through the Microsoft certification yet.  I ended up using a program called Commview and have discovered that the issue is as follows;

    Lync keeps sending a 200 ok stating Session-Expires: 1800;refresher=uas. This implies that the PBX will be responsible for an update or a re-invite to keep the session alive but Broadvox is not receiving the update or re-invite causing them send a bye.

    Friday, December 9, 2011 9:37 PM
  • It looks very similar to this issue, however the patch in question is for OCS not Lync.

    http://support.microsoft.com/kb/977937/

     

    Friday, December 9, 2011 9:44 PM
  • Hm,

    have you tried to disable the mediabypass and refer support?

    You can also check the Lync powershell properties for trunk configuration.

    Start a trace on the frontendserver with mediation, S4 and Sipstack to see what happends on the Lync mediation server


    regards Holger Technical Specialist UC
    Saturday, December 10, 2011 8:49 AM
  • Media bypass and refer support are already disabled, and Lync does not have a way to adjust the "Session-Expires" SIP parameter.

    What exactly am I looking for in the SIP trace?  Its already been established what the problem is, I just dont know how to go about fixing it.  Could someone from Microsoft possibly chime in on this? 

    Monday, December 12, 2011 4:58 AM
  • Hi URNVS,

    Here is a document about Configuring a Broadvox SIP Trunk but for Communications Server 2007 R2.

    Please check if there is any missing in your configuration accordingly. Hope helps. If any, please feedback.


    Noya Liu

    TechNet Community Support

    Tuesday, December 13, 2011 9:26 AM
  • Unfortunately that link doesnt help, as the SIP trunks are already configured.  If you re-read the posts you will notice that my exact issue is that calls are being dropped at 30 minutes.
    Tuesday, December 13, 2011 3:28 PM
  • The answer is to edit the MediationServerSvc.exe.config file and add the following;

    <appSettings>
          <add key="GatewayIgnoreMediaTimeout" value="True" />
    </appSettings>

    • Marked as answer by Noya Lau Wednesday, December 14, 2011 9:49 AM
    Tuesday, December 13, 2011 11:05 PM