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OCS/MOC2007 immediately sends BYE after INVITE to our SIP PSTN gateway RRS feed

  • Question

  • We have developed our own SIP PSTN gateway  to connect MOC users to different PBX types.

    Our gateway worked fine with OCS/MOC 2005 without problems, e.g. the message sequence as seen by the gateway is:

    from OCS : INVITE (with encapsulated RequestSystemStatus)
    to OCS : SIP 200 OK ( with encapsulated RequestSystemStatusResponse)
    from OCS: ACK
    from OCS: INFO ( with encapsulated GetCSTAFeatures)
    to OCS: SIP 200 OK ( with encapsulated GetCSTAFeaturesResponse)
    ...
    from OCS: INFO ( with encapsulated MonitorStart)
    to OCS: SIP 200 OK ( with encapsulated MonitorStartResponse)


    But it does not work with the new OCS/MOC 2007. The configuration seems to be correct so far, e.g. the OCS/MOC2007 does connect to the gateway.

    But the SIP message sequence always ends with a BYE shoretly after the INVITE:

    from OCS : INVITE (with encapsulated RequestSystemStatus)
    to OCS : SIP 200 OK ( with encapsulated RequestSystemStatusResponse)
    from OCS: ACK
    from OCS: BYE ( immediately following the ACK above)


    any ideas?


    Tuesday, May 8, 2007 9:31 AM

Answers

  • ... I have found the reason for this behaviour: 

     

    our gateway did not send a 'Contact:' field in the SIP header.

     

    It seems that OCS2005 has no problem with a missing 'Contact:' . Furthermore the OCS2005 even stops working if the 'Contact:' headerfield is present ! 

     

    but OCS2007 needs the 'Contact:' headerfield. The content is not important. It seems that the OCS2007 accepts any value - even it is not a valid SIP uri.

     

     

    I have fixed our gateway to make a distinction via the 'User-Agent' SIP header field in such a way that: 

    • if it is an OCS2005 client - than do not send the 'Contact' headerfield
    • if it is an OCS2007 client - than do send it

     

     

     

     

     

    Wednesday, May 9, 2007 8:49 AM

All replies

  • ... I have found the reason for this behaviour: 

     

    our gateway did not send a 'Contact:' field in the SIP header.

     

    It seems that OCS2005 has no problem with a missing 'Contact:' . Furthermore the OCS2005 even stops working if the 'Contact:' headerfield is present ! 

     

    but OCS2007 needs the 'Contact:' headerfield. The content is not important. It seems that the OCS2007 accepts any value - even it is not a valid SIP uri.

     

     

    I have fixed our gateway to make a distinction via the 'User-Agent' SIP header field in such a way that: 

    • if it is an OCS2005 client - than do not send the 'Contact' headerfield
    • if it is an OCS2007 client - than do send it

     

     

     

     

     

    Wednesday, May 9, 2007 8:49 AM
  •  hgt@ilink.de wrote:

    ...

     

     

    I have improved our gateway to make a distinction via the 'User-Agent' SIP header field in such a way that: 

    • if it is an OCS2005 client - than do not send the 'Contact' headerfield
    • if it is an OCS2007 client - than do send it

     



    meanwhile we have simplified the solution mentioned above by sending always a 'Contact' headerfield *and* additionally appending a transport parameter, e.g.

    Contact: <sip:192.168.178.23:5070;transport=tcp>

    Thus we have eliminated the need to differantiate between OCS2005 and OCS2007.




    Tuesday, April 29, 2008 7:13 AM