Speech server ack packet RRS feed

  • Question

  • We are using speech server to initiate outboud calls to a Cisco box. Here is what is happening, I am really hoping that someone can help me out.

    1. Speech Server (MSS) sends and INVITE sip request.

    2. Cisco box (that is the gateway we use) reponds with 100 - trying

    3. Gateway responds with 183 session progress

    4. My phone rings and then Cisco sends a 200 OK to MSS

    5. At this point it is my understanding that MSS should send an ACK and the call is set up. However, I never see the ACK from MSS so the gateway just drops the call.


    If anybody knows what might be a problem here and how to fix it I would appreciate it. I am not sure if this is non-standard behaviour on the part of my gateway or MSS and if it is MSS then what should I do to get that ACK sent?


    Thank you.


    Monday, May 5, 2008 9:51 PM

All replies

  • Have you resolved this?  I don't know off-hand what the expected behaviour is.  AFAIK you're the 1st person to report issues in this area, so I would 1st look elsewhere for the root cause.  Was there any error logged to the NT Application event log by Speech Server?  Or any errors logged by Cisco?  There must be an error somewhere justifying the dropped call.

    Tuesday, May 13, 2008 10:18 AM
  • If you have not resolved it, please contact our technical support via the http://support.microsoft.com/gp/assistsupport web page or if you are in the US, you can call (800)936-5800 and ask for support on Speech Server.  They will need to see network traces showing the SIP messages & the missing ACK and Speech Server .etl logs (select all options in the Speech Server admin console).

    Wednesday, May 14, 2008 11:01 AM
  • I have not resolved this yet. I did call MS support and I am working with Ramesh there to try to get this resolved but we have not had much luck. I will post an answer here once we figure it out for others to see.

    Wednesday, May 14, 2008 1:19 PM