Inconsistent SIP 180 ringing headers RRS feed

  • Question

  • Hey,

    Our SIP provider have be trolling through their logs trying to figure out why ring back is not working. They are seeing inconsistent results:

    Sometimes they receive 180 ringing YES (I would assume this to mean that Lync is providing ring back and therefore the telco doesn't need to??). Other times it is completely omitted from the header.

    Any ideas?



    Monday, August 22, 2011 10:07 PM

All replies

  • Hi Andrew,

    Do the lync outbound callers not get ringback or the pstn callers give calls to lync not get ringback?

    Please check you gateway configuration does not block the 180 to send to SIP provider.

    The following post has similar problem with you, hoping it can help you:


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.
    Tuesday, August 23, 2011 8:43 AM
  • Hey,

    Thanks for your reply. The issue is with incoming calls from the PSTN to Lync. Our mediation server directly connects to an Acme Packet Session Border Controller at our Telco. Sometimes they receive 180 ringing (which they say indicates that Lync should be providing the ring back but isnt) and other times they dont recieve a 180 in the header at all.

    The link you provided is very similar but we dont have a gateway between Lync and the telco.






    Tuesday, August 23, 2011 8:55 AM

    Is your med server patched to the current version?

    Tom Arbuthnot, Consultant Modality Systems
    Blog: Lync'd Up Blog Subscribe for updates: Email or RSS
    Twitter @tomarbuthnot
    Tuesday, August 23, 2011 7:18 PM
  • Hey Tom,

    Thanks for your reply.

    Yes our mediation server is currently patched to the latest version found here - http://support.microsoft.com/kb/2493736






    Tuesday, August 23, 2011 8:42 PM