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Troubleshoot PSTN call failures RRS feed

  • Question

  • I'm getting the following type of alert several times a day on my mediation servers.  The gateways are up, there are ongoing active calls, and I have not had an actual call failure.  Is there any way to determine more about what calls caused this alert?

     -----

     The Mediation Server service has encountered a major call completion problem with these gateway peer(s).

    Affected PSTN Gateway Service Cluster(s):
    172.31.0.14
    Cause: Calls to this gateway failed 5 times with failure final responses.  Check other MOM alerts for more details.
    Resolution:
    If the failure is MEDIATIONSERVER_GATEWAY_SDP_NEGOTIATION_FAILED (Event ID: 25039), make sure that configuration for SRTP is consistent between the Mediation Server and the GW, and that there is intersection in the voice codec supported on the gateway and on the Mediation Server.  If the failure is due to CALL_FAILURES_DUE_TO_UNEXPECTED_GATEWAY_INTERACTION, there is some internal issue with the gateway peer's link to the Mediation Server (misconfiguration, load) that is causing it not to complete calls.  Please consult the failure reports on the Monitoring Server for more details.

     

    Tuesday, August 30, 2011 12:14 AM

Answers

  • Both of the above suggestions are good ways to determine what the problem is, as they will give you more information on what is causing the problem.

     

    The reason you are getting these messages is that the Lync Mediation server queries the PSTN gateway with OPTIONS requests every minute. After 5 are answered incorrectly (or not answered at all) the Mediation Server may mark the gateway as being down or having degraded service. The S4/SIPStack logging will allow for you to see the OPTIONS requests go out to the gateway and possibly see the answer. This answer will be the additional information that you would need to troubleshoot this issue further.

    If the gateway is not responding to them or sending an error message back you shoul;d be able to work with your gateway vendor to determine how to pose a legitimate response to the OPTIONS request (a 200 OK response). Most instances of this can be corrected via gateway configuration or firmware update. Some instances of this may come from a gateway that is not supported for use with Lync. Please verify that your gateway is on UCOIP list as a support IP/PSTN gateway. This list can be found here:

     

    http://technet.microsoft.com/en-US/lync/gg131938.aspx


    Richard McGiboney, Support Escalation Engineer, Microsoft
    • Proposed as answer by Sean_Xiao Friday, September 2, 2011 1:32 AM
    • Marked as answer by Sean_Xiao Tuesday, September 6, 2011 1:55 AM
    Tuesday, August 30, 2011 11:59 PM

All replies

  • You should implement the monitoring role which will give you detailed statistics on calls and should allow you to troubleshoot this issue.

    Mike


    If a post is helpful, please take a second to hit the green arrow on the left, or mark as answer, thanks

    MCITP: Lync, Exchange 2010 & Server Administrator

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    Tuesday, August 30, 2011 10:51 AM
  •  

    On Mediation Server using Lync Logging tool take trace of S4 and Mediation Server compoments with All level,All Flags  .... and analyze them :-)

     

    -Santosh

     


    Microsoft Unified Communications Team
    Tuesday, August 30, 2011 11:19 AM
  • Both of the above suggestions are good ways to determine what the problem is, as they will give you more information on what is causing the problem.

     

    The reason you are getting these messages is that the Lync Mediation server queries the PSTN gateway with OPTIONS requests every minute. After 5 are answered incorrectly (or not answered at all) the Mediation Server may mark the gateway as being down or having degraded service. The S4/SIPStack logging will allow for you to see the OPTIONS requests go out to the gateway and possibly see the answer. This answer will be the additional information that you would need to troubleshoot this issue further.

    If the gateway is not responding to them or sending an error message back you shoul;d be able to work with your gateway vendor to determine how to pose a legitimate response to the OPTIONS request (a 200 OK response). Most instances of this can be corrected via gateway configuration or firmware update. Some instances of this may come from a gateway that is not supported for use with Lync. Please verify that your gateway is on UCOIP list as a support IP/PSTN gateway. This list can be found here:

     

    http://technet.microsoft.com/en-US/lync/gg131938.aspx


    Richard McGiboney, Support Escalation Engineer, Microsoft
    • Proposed as answer by Sean_Xiao Friday, September 2, 2011 1:32 AM
    • Marked as answer by Sean_Xiao Tuesday, September 6, 2011 1:55 AM
    Tuesday, August 30, 2011 11:59 PM
  • Hello Daniel,

    Could you please share the resolution?

    Tuesday, April 16, 2013 5:12 AM
  • In our case it turned out to be incorrect responses by the gateway when an invalid number was dialed.  The incorrect responses resulted in the mediation server making the gateway down.

    • Proposed as answer by PaulSkeps Thursday, August 10, 2017 6:42 AM
    Tuesday, April 16, 2013 4:22 PM