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Voice Delay with outbound calls RRS feed

  • Question

  • Users are complaining about an initial delay when making outbound calls.  Usually the caller never hears the greeting from the person they are calling.  The rest of the conversation is fine.  In general, we do not have any voice quality issues.  We have a simple setup, OCS 2007 R2 Standard Edition, Mediation Server, and a Dialogic Gateway with 50 users.  I've contacted Dialogic for assistance, but they have yet to provide me with a solution.
    Friday, May 22, 2009 7:44 PM

Answers

  • If you want to investigate that in detail you could install wireshark on mediation server and capture an outgoing call. There is a lot of VoIP analysis built into wireshark but you still need someone knowing a bit about SIP (and RTP) to see if early media is negotiated and to decide if incoming RTP stream starts too late. You can decode and listen to incoming audio data to decide if the greeting is missing there already - in that case it's really gateway and/or pbx related.

    There also may be a configuration switch on the gateway to enable early media (and PRACK).


    Johann Deutinger | MCTS Exchange 2007 / OCS 2007
    Tuesday, May 26, 2009 4:34 PM
  • Not sure if related, but we had problems with initial silence on our calls (up to 8 seconds on some calls).  We are using a Cisco 3845 router for our gateway.  The problem was semi-resolved by disabling the windows firewall on the mediation server (windows 2008 64bit).  So, now there is occasionally a slight overlap from of the voice & the 'ringing' at the moment, but it is better than a long stretch of silence.

    • Marked as answer by Dominic Lanza Wednesday, June 10, 2009 1:55 PM
    Wednesday, May 27, 2009 3:43 PM

All replies

  • Are any of the OCS roles virtualized, or is all this deployed on dedicated hardware?
    Jeff Schertz, PointBridge | MVP | MCITP: Enterprise Messaging | MCTS: OCS
    Sunday, May 24, 2009 12:29 PM
    Moderator
  • Also, what client is used? MOC or hardware?

    Drago
    Sunday, May 24, 2009 8:08 PM
  • This is an "early media" issue. Gateway qualification for OCS R2 uses a lot of test cases in that area. Have you checked for upgrading your gateway to R2 certified firmware (if it is DMG 1000/2000 series, other models are not R2 certified). Sometimes early media issues are caused by PBX/PSTN connection as well.
    Johann Deutinger | MCTS Exchange 2007 / OCS 2007
    Monday, May 25, 2009 8:52 AM


  • If it helps - we suffered a little with this (and when first answering a call - a pause before voice is working as it should) - but we do not have a Dialogic gateway.

    We set the prioirty on the local machines for communicator.exe to HIGH & switched on QoS for the entire network (we have switches that respect DiffServ & also - don't forget to add the registry setting to make it work).

    For almost all users - this fixed the 'pauses'.  We have a few guys with older, slower laptops that the pausing is still a minor issue - but it does not stop them from using OCS.


    Regards

    Paul Adams
    Monday, May 25, 2009 5:13 PM
  • Both Servers are dedicated hardware, no virtualization.

    Using 40+ MOC clients, and 3 Polycom CX700s, both of the client types are experiencing the problem. 

    The Dialogic DMG2000 is not patched with the latest firmware that is R2 qualified.  I will work on getting this in place ASAP.

    I will also try setting the priority on Communicator.exe.  As the QOS setup will take more time and different switches, I'm going to hold off on taking any action with QOS.
    Tuesday, May 26, 2009 12:54 PM
  • Hi,

    I don't think it's a problem with the moc ore mediation server.

    It's configuration, firmware of your gateway to the pstn. We had same problems and fix it with the right isdn settings of our pbx.
    Tuesday, May 26, 2009 2:14 PM

  • We are only about 10 OCS clients at the moment - but will be about 60, like yourself.

    My 2 cents - if you get the same problem on both clients (software & hardware) then I would not bother changing the MOC desktop priority.

    I'd update the Dialogic first.


    Paul
    Tuesday, May 26, 2009 4:18 PM
  • If you want to investigate that in detail you could install wireshark on mediation server and capture an outgoing call. There is a lot of VoIP analysis built into wireshark but you still need someone knowing a bit about SIP (and RTP) to see if early media is negotiated and to decide if incoming RTP stream starts too late. You can decode and listen to incoming audio data to decide if the greeting is missing there already - in that case it's really gateway and/or pbx related.

    There also may be a configuration switch on the gateway to enable early media (and PRACK).


    Johann Deutinger | MCTS Exchange 2007 / OCS 2007
    Tuesday, May 26, 2009 4:34 PM
  • I changed the "RFC 3960 Early Media Support" setting from OnDemand to Always.  Seems to have improved the situation significantly.

     

    http://www.dialogic.com/support/helpweb/mg/iw1383.aspx

     
    I plan on doing more testing before I can say its fixed for sure.

    Tuesday, May 26, 2009 6:11 PM
  • Not sure if related, but we had problems with initial silence on our calls (up to 8 seconds on some calls).  We are using a Cisco 3845 router for our gateway.  The problem was semi-resolved by disabling the windows firewall on the mediation server (windows 2008 64bit).  So, now there is occasionally a slight overlap from of the voice & the 'ringing' at the moment, but it is better than a long stretch of silence.

    • Marked as answer by Dominic Lanza Wednesday, June 10, 2009 1:55 PM
    Wednesday, May 27, 2009 3:43 PM
  • The "RFC 3960 Early Media Support" setting resolved the problem.
    Friday, May 29, 2009 1:53 PM
  • It turns out that the Dialogic settings did not fix the problem.  I have turned off the Windows Firewall on the Mediation Server and this appears to have resolved the problem.  I'm contacting Microsoft support for clarification on why this is a problem and what to do.

    Wednesday, June 10, 2009 1:55 PM
  • Thanks - if you could post what MS says about it, that'd be great.  I haven't had the time to pursue it with them.
    Friday, June 12, 2009 2:40 AM
  • I don't have a reponse from Microsoft yet, but I wanted to add a couple bits of information. 

    My mediation server has a single NIC interface.  I don't know if this has any bearing on the problem or not. 

    Microsoft did say when I talked with them that they had 2 other open cases that had experienced the exact same problem.
    Friday, June 12, 2009 12:17 PM
  • How do we Disable Early Media on Dialogic 1000 ?
    Where exactly on dialogic this setting is ?
    Wednesday, September 9, 2009 10:14 AM
  • Dominic, did you ever hear anything more back from Microsoft on this?

     

    Thanks.

    Monday, September 14, 2009 3:03 PM
  • No, and I have not pursued an answer.  I just turned off the firewall on the mediation server and went on.  The firewall being disabled was not significant enough of a security risk on our environment.
    Monday, September 14, 2009 3:15 PM
  • All

    I have seen this in 2 environments now. and if you add a rule to the windows firewall for UDP, and associate it with the mediationserversvc. This usually fixes the problem. it appears that  the installer does not always open the correct ports.


    Mitch Roberson |MCITP:Enterprise Server Admin, Messaging |MCTS:OCS with Voice Achievement |MCT
    Thursday, September 17, 2009 1:15 PM