PBX coexistence and SIP 480 from MOC RRS feed

  • Question

  • Scenario: OCS 2007 R2 with PBX coexistence

    "OCS 2007 R2 Resource Kit" (p. 373) says that when detecting a looping call, MOC sends out 480 "Temporarily unavailable" response to PBX. This is done assuming that the PBX treats the response as a way to say "stop ringing here but continue ringing on the other possible endpoints".

    "Integrating Enterprise Telephony with Office Communications Server 2007 R2" whitepaper from March 2009 however states (p.32) that if a user has set his MOC to DND status, a SIP 480 will be sent to the PBX and this will stop also the user's telephone from ringing.

    Furthermore, the OCS Reskit says (p. 375) that if the user has DND status in MOC, the incoming calls will in fact continue ringing on the phones due to the PBX being responsible for routing to voice mail.

    I have two questions here:
    1. Which of the two given cases is true: will the PBX stop ringing on all endpoints or only the endpoint that returned 480?
    2. How's response 480 "temporarily unavailable" related to RFC 2543 definition of response 482 "Loop Detected". It would at least from the surface seem more logical to use 482 here although due to not having an awfully long and colorful background with SIP and telephony I may not be seeing the complete picture here :)
    There's also a typo in reskit where response 480 is incorrectly referred as "temporarily available", which may be a bit confusing.
    Tuesday, June 16, 2009 5:54 PM

All replies

  • Hi Markus,


    > will the PBX stop ringing on all endpoints or only the endpoint that returned 480?


    I can only answer this question for the PBX I have which is an Aastra MX-ONE.


    When I set my MOC to DND, my mediation server (R2) will indeed send back a "480 Temporarily Unavailable" message.

    My IP-telephone in the PBX (the other "fork" of my dual forking extension) will however keep ringing.


    I think the third bullet on page 375 in the Resource kit describes this best:

    "When Do Not Disturb is set on MOC, calls will still ring on the PBX phone instead of being suppressed.

    OCS enables calls to ring on the PBX phone because routing calls to the voice mail system is handled by the PBX system.

    For Do Not Disturb to work consistently, the dual forking user must manually set the PBX phone to Do Not Disturb as well."


    But I can of course see scenarios where you would like even the PBX phone to be silent once DnD is set in MOC.



    Thursday, June 25, 2009 12:42 PM