Invalid Media Description RRS feed

  • Question

  • Hello,


    I'm getting this error in the event log from MSS:


    Application Error 50000: An exception occurred in the Speech workflow with Id cec8ce2e-07c1-4a25-ab07-cfbae8f9b468. The exception was: An invalid media description was received from the remote end.


    Here's the SDP from the INVITE coming from MSS:


            o=- 0 0 IN IP4
            s=Microsoft Speech Server session
            c=IN IP4
            t=0 0
            m=audio 38400 RTP/AVP 114 115 4 0 8 101
            a=rtpmap:114 x-msrta/16000
            a=fmtp:114 bitrate=12000
            a=rtpmap:115 x-msrta/8000
            a=fmtp:115 bitrate=12000
            a=rtpmap:101 telephone-event/8000
            a=fmtp:101 0-16


    And here's the SDP in the OK from my gateway:


            o=8888888 8000 8000 IN IP4
            s=SIP Call
            c=IN IP4
            t=0 0
            m=audio 5004 RTP/AVP 4
            a=rtpmap:4 G723/8000


    4 is Media Format: ITU-T G.723, and it is listed as one of the formats in the initial INVITE. 


    Why doesn't this work?





    Wednesday, April 25, 2007 1:51 PM


  • Ok, we figured this one out.


    We're using a Grandstream SIP phone and an ht488 gateway for testing, and we had to make this change to the config screen:


    Send DTMF:   in-audio     via RTP (RFC2833)     via SIP INFO


    Originally it was set to "in-audio".


    This adds a 101 to the media description line in the SDP, and also Media Attribute (a): fmtp:101 0-11



    Thursday, April 26, 2007 11:59 AM