Thread: Dual forking of calls from PSTN not working RRS feed

  • Question

  • Hello. I apologize if this has already been covered in detail here. I could not find a suitable thread.

    I'm configuring OCS to integrate with an IP/PBX by way of a Media Gatway and Mediation Server.

    Here is my problem:

    When I call an internal user via communicator, that user's communicator client and their IP/PBX phone ring at the same time (dual forking). But when I call in from the PSTN, only the communicator client pops.

    I've continued to search through the debug logging to try and see if there are differences about the way the calls are presented to the Front End Server, but the only difference is that the outside call comes inbound from the Mediation Server.

    When I make the internal call it immediately routes both to communicator and the Mediation server.

    Is there some sort of evaluation that is done on the inbound invite to make the decision to fork? The user seems to be set up correctly for forking since it is working in 1 scenario.

    Any help in understanding how inbound numbers should be formatted to trigger forking would be appreciated.

    Thank you so much.

    Wednesday, April 29, 2009 8:17 PM


  • I figured out my issue...remember - it always helps to read the documentation.

    I'll outline my mistake here so that others won't fall into my trap.

    Here is how I was configured:

    PSTN -> Media Gateway -> Mediation Server -> OCS

    I was expecting inbound calls from the PSTN to hit the OCS user, but then spin the call back out to the Mediation Server since the user was PBX-enabled. The next hop on the Mediation server was to my IP/PBX.

    That is not supported nor expected behavior. Dual forking for OCS will only occur if the a call is made to an internal user from inside OCS. When OCS pops the internal user's client, a new call will be spun out Mediation Server to wherever your next hop is (typically a PBX, Proxy, etc.)

    For dual forking to work the way I expected, your architecture should look like this:

    PSTN -> Media Gateway -> PBX -> Mediation Server -> OCS

    and the PBX is responsible for forking inbound calls to OCS - whoops.

    Luckily when your company is the creator of the IP/PBX you're using it's easy to adapt/test/get it working; which I did today.

    Sorry for the noise - I just figured someone else would do this.


    Friday, May 1, 2009 8:30 PM