Batteling the Mediation server (or; this time we blame Cisco)

I'm sorry I haven't posted in a wile. But I have been busy doing other implementations. The two last days however, have been more quiet (Easter is almost upon us in Norway). I have now tried to install a mediation server, and connect the OCS world to the rest of the world through a SIP trunk to CUCM (v7).

Installing the mediation server, adding a certificate, and configuring dialing rules and routes was pretty easy. I've made one simple rule for internal dialing with 4 extensions, and one for the rest of the world (for testing purposes limited to dialing the Norwegian dial plan).

Setting up the trunk on CUCM seemed fairly easy to, but I do however have on problem with the configuration I set up. And if any of you out there have a solution to it, please let me know :)

Dialing from a Cisco phone to a pure MOCS extension is working with RTP in both directions. But when dialing from MOCS and out, all calls are blocked with a 503 (Service unavailable) message from the CUCM. I can see the call in CUCM's traces), and I see the same when tracing on the Mediation server.

I've searched around, and tried to figure out what is wrong. The only thing I think might be it is a problem related to how the OCS uses + in front of numbers when calling. There is a fix for this in OCS 2007, but it is not released for R2 (at least yet).

I have verified translation patterns, css and partitons on CUCM. And the digit analyzer is giving me an OK.

Does anyone out there know the reason for the 503 error code? (The SIP trunk is unsecured and is set to use MTP)

Comments

  1. Hey I have exactly the same config and problem. Still working on it. I will post if I find the solution.

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  2. Right - Looked into this one some more. Just as with you, Call routing was confirmed and working at both ends. OCS to CUCM and CUCM to OCS confirmed with Dialling Analyser and Route Helper.

    Calls were also working from CUCM to an OCS Endpoint. Calls from OCS to a CUCM Endpoint werent working (the dreaded 503 service unavailable). After trolling the RTMT logs from the Cisco end I noticed that SIP was working fine initially then it was trying to communicate with the "Communication Server" listening IP on the mediation server. Basically I had two IP's one on each NIC for the Mediation Server. The IP's were on the same Subnet.
    Changed the Medation serbver to use a single IP address for the gatway and the OCS pool. No more 503.
    I havent tried to re-configure back to seperate cards and IP's yet. Just happy to be Rid of the 503 for now. Give it a shot and let me know if you had the same issue.

    ReplyDelete
  3. Thank you for your tip, I have the same configuration on my mediation server (Two nic's on the same subnet). I will try it out when I return at work later next week (I am at a customers site in the beginning of this week). I'll put a post or a comment on how things work out.

    ReplyDelete
  4. The reason CUCM fails the call is most likely because it was receiving a SIP INVITE from the inside OCS interface. CUCM would have given a 503 because the inside interface is not defined on CUCM as a SIP trunk. CUCM needs the SIP trunk configured to receive the invite.

    Does anyone know why OCS R2 Mediation does not use its outside interface when sending the SIP invite to CUCM?

    Sounds like a Microsoft bug?

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  5. I had the same problem and traced it back to a particular Windows Update... http://support.microsoft.com/?kbid=956829

    Uninstalling that update fixed my 503 problem.

    ReplyDelete
  6. I have CUCM 7.1.2 setup with OCS R2. We cannot receive calls the outside the OCS client. Any help or documentation for the CUCM would be appreciated.

    Thanks.

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  7. Could you be more spesific on your problems? Any logs? Any error messages? What call scenarios do work?

    ReplyDelete
  8. I've had a similar problem. I had 2 IPs configured, 1 for server listening and 1 for gateway listening. I just changed it to use a single IP and it now works.
    Hope this helps.

    ReplyDelete

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