Calls OCS direction CCM 4.2 - Crackles RRS feed

  • Question


    Hello there,


    i've configured a siptrunk between OCS and CCM 4.2 (Cisco Callmanager) and i can do calls in both direction. I have an issue regardings voice quality.

    The voicestream from the CCM environment direction OCS is of good quality, which means that the OCS User hears the CCM User in very good quality.The other direction crackles very much, specially when there ist some talking on the ocs side.

    For the purpose of evaluating OCS i didn't not follow the Microsoft recommendations for the Mediation Server. The Mediation Server has only one Networkadapter and is running on a virtual Machine. But there is no load on the server and the performance should be enough for testing with a few lines.

    Has anybody experienced simliar ? Could the crackles be caused by the installation scenario ? Is there any possibility to tune voicequality from OCS->CCM ?

    Thank you for help,






    Friday, August 3, 2007 6:56 AM


  • Hi Daniel,


    I think this is a common problem a few people including my self have encountered. What help fixed my problem was using IOS hardware enhanced MTP resources using an ISR. The software MTP callmanager resources seem to cause the poor audio on the Callmanager side. Seeing as the MTP is required under 4.X configuration it is always best to go with the hardware option.


    Let me know if you need more info.




    Monday, August 6, 2007 3:57 PM

All replies

  • Hi Daniel,


    I think this is a common problem a few people including my self have encountered. What help fixed my problem was using IOS hardware enhanced MTP resources using an ISR. The software MTP callmanager resources seem to cause the poor audio on the Callmanager side. Seeing as the MTP is required under 4.X configuration it is always best to go with the hardware option.


    Let me know if you need more info.




    Monday, August 6, 2007 3:57 PM
  • Hello Chris,


    thank you for your reply. I will check this out and perhaps post further questions later on

    Nevertheless i will set up a dedicated Mediation Server too for further testing. I will give a Feedback if i have any results.






    Monday, August 13, 2007 3:43 PM
  • Hi Daniel,


    Just as a bit of a followup how did you go?


    Also wanted to point out that using IOS MTP for this purpose doesnt mean that you require expensive DSP cards in your router. You can also use the router CPU to act as a MTP using the following commands in the dsp profile.


    dspfarm profile 101 mtp
     codec g711ulaw
     maximum sessions software 100
     associate application SCCP

    Hope this helps everyone and avoids extra cost for your deployments with Callmanager.




    Friday, September 7, 2007 4:13 PM
  • Hello there,


    I am trying to do a similar thing. I successufully integrated OCS2007 with a Alcatel PBX and a Cisco Call manager 5.0.

    No way with CCM 4.2.

    Can you please post the actual configuration you did on CCM4.2?

    That would help big time

    Thank you in advance



    Wednesday, September 12, 2007 2:46 PM

    Hi beppe,


    I used a IP-IP GW to complete the configuration with the 4.2.3 Callmanager setup using a H323 gateway(Cisco recommended way to integrate with IP-IP GW). To save repeating the configuration, checkout the post I made in the following thread. It has the full ip-ip gw setup for 5.x and 4.2.3.


    SIP trunk between OCS and Cisco Unified Communications Manager


    Using IP-IP GW does have some benifits and allows you to do a few things that maybe you wouldnt be able to do with a straight SIP trunk.


    With the 4.2.3 H323 setup just ensure that the MTP required is selected and that you have a inbound Calling search space that will allow you to do trunk to trunk transfers so that MOC users can reach the PSTN through Callmanager if you choose to route calls that way.


    Let me  know if you have more questions.




    Wednesday, September 12, 2007 4:45 PM

    Hi Giuseppe, Have you integrated succesfully Alcatel PABX ? Can you send me a guide to do this, because i start to do but i have a lot of problem to understand how OCS / Mediation Server "talk" with SIP ALCATEL . I have a ALcatel oxe 7.1.1 and OCS 2007 ...

    Thanks in advance



    Thursday, March 6, 2008 4:32 PM
  • Dear Daniel.

    i bought the CCM 6.0(1) and i installed the OCS 2007 in my lab environment.
    i want to make and receive call from/to MOC 2007.
    can you suggest me some links explaining the OCS / CCM step by step integration??
    many thanks for your help.

    Wednesday, March 12, 2008 4:36 PM
  • Hi Lory,


    There a couple of ways to do this. The first is a direct SIP trunk from CCM to OCS. The other is to use a Cisco router configured as a IP-IP GW to do number translations and act as a MTP for the SIP trunk from the Callmanager enviroment. The second method with the Cisco router actually works the best and will give you the most flexibility. Neither method is currently being supported by MS. I could talk about that more but dont want to say something I shouldnt. MS is reviewing both methods lets just leave it at that. Where I work we are running a pilot using the second method and currently have a handful of users with VoIP enabled with plans to expand to a couple of hundred by April. There is another thread with the full configuration for the IP-IP GW posted by myself which if you cant find I will repost here. It will allow connection to a CCM 4.2.3 cluster with H323 and a SIP connection to 6.X cluster. I am sure there are other ways to connect the two enviroments but these are the ones we have tried and the router solution the best one.


    Hope this helps.




    Wednesday, March 12, 2008 5:55 PM
  • Hello,
    I am not sure, If I understand your saying correct. Please tell me: are you using mediation server, or are you connecting CCM and OCS directly, without mediation server?
    I am tryng to connect CCM 6 and OCS 2007.
    Thanks you, for your answers in advance.


    Wednesday, March 26, 2008 7:04 AM
  • Hi Rok,


    Yes I am using a mediation server ---------> ip-ip GW ------>CCM 5/6.X. The ip-ip GW takes the places of a PSTN connection and connects via IP to the Cisco callmanager and OCS. The benifit of this is that the IP-IP GW is capable of both RFC 3966 (OCS) and ITU E.164 (CCM) which means it can deal with the plus sign for Callmanager. It can also act as an MTP device for CCM and link to a earlier version of Callmanager as a H323 gateway or in the 6.x version as a SIP trunk. This is important for DTMF signaling for converting inband to out of band signaling for protocols like SCCP.


    You can connect CCM 6.X via SIP to OCS directly but it is not supported. You need to set the allowed digits on the inbound trunk to the digits required for your extensions whether it be 5 or 10 digits or what ever. This is a very limited setup and depending on the amount of digits you elect to have inbound thing like LD, international and local calling could be limitied and more importantly you wont be able to route 911 without special configuration in OCS and CCM.


    Hope this helps.




    Wednesday, March 26, 2008 2:22 PM
  • Hi Chris,
    I am still having problems trying to connect CCM 6 and OCS 2007. On this link
    please check my logging list, where you can see, what is happening when I am trying to call from CCM (sip:540@ to OCS. Call is unsucesfull.
    Can someone send me that kind of log of sucesfull log, to see where is mistake.

    Thanks in advance,



    Thursday, March 27, 2008 2:24 PM
  • I had a quick look at the log and couldnt tell to much. Anyone else willing to have a go at it go for it. I see that the mediation server gets the inbound call and matches it to a extension but then generates some kind of error that I am not sure what it is.


    When I googled it I cam up with "The certificate chain was issued by an untrusted authority". Not sure why this would happen as you shouldnt be using TLS to make the connection. Hope this helps. Connecting directly from CM to OCS is also not supported just something you should keep in mind as you wont be able to go into production with this setup and get support from MS.





    Thursday, March 27, 2008 3:34 PM
  • Chris,
    I also don't have any idea, why there is a certificate chain error. Between CCM and OCS is used SIP protocol over port 5060 and there is no TLS communication. Does anyone have any idea, what to check, to get rid of this problem?

    I am pasting details about this error from Snooper:
    TL_ERROR(TF_COMPONENT) [0]0454.0F98::03/27/2008-13:52:07.953.0000001d (MediationServer,ProxyCall.ProxyParticipateComplete:343.idx(1534))( 009A2F17 )$$START-MEDIATIONSERVER
    MediationCall: 1a1f675cc786492eab782b264296f2f1
    CallId: 0464ad51-42f5-42ca-a5dd-0680f121c7da
    From: sip:540;phone-context=unknown@unified.si;user=phone
    To: sip:193;phone-context=SRC.SI@unified.si;user=phone
    Direction: Inbound
    Start-Line: Exception: ErrorCode=-2146893019
    Microsoft.Rtc.Signaling.TlsFailureException: The certificate chain was issued by an authority that is not trusted ---> Microsoft.Rtc.Internal.Sip.TLSException: outgoing TLS negotiation failed; HRESULT=-2146893019
       at Microsoft.Rtc.Internal.Sip.TlsTransportHelper.HandleNegotiationFailure(Int32 status, Boolean incoming)
       at Microsoft.Rtc.Internal.Sip.TlsTransportHelper.OutgoingTlsNegotiation(TransportsDataBuffer receivedData, TransportsDataBuffer& pDataToSend)
       at Microsoft.Rtc.Internal.Sip.TlsTransportHelper.NegotiateConnection(TransportsDataBuffer receivedData, TransportsDataBuffer& pDataToSend)
       at Microsoft.Rtc.Internal.Sip.TlsTransport.DelegateNegotiation(TransportsDataBuffer receivedData)
       at Microsoft.Rtc.Internal.Sip.TlsTransport.OnReceived(Object data)
       --- End of inner exception stack trace ---
       at Microsoft.Rtc.Signaling.SipAsyncResult.ThrowIfFailed()
       at Microsoft.Rtc.Signaling.Helper.EndAsyncOperation[T](Object owner, IAsyncResult asyncResult)
       at Microsoft.Rtc.Signaling.Helper.EndAsyncOperation[T](Object owner, IAsyncResult asyncResult, String operationId)
       at Microsoft.Rtc.Signaling.SignalingSession.EndEnter(SipInviteAsyncResultWrapper asyncWrapper)
       at Microsoft.Rtc.Signaling.SignalingSession.EndParticipate(IAsyncResult asyncResult)
       at Microsoft.RTC.MediationServerCore.ProxyCall.ProxyParticipateComplete(IAsyncResult ar)
    Thursday, March 27, 2008 5:33 PM
  • Hi Rok,


    You may have a problem between your front end server and the mediation server certificate. I know there is an issue where the mediation server looks like it has a certificate registered but it really isnt. I would repeate the certificate process on the mediation server and see if that fixes it. Going by this trace you certainly have a certificate issue.





    Thursday, March 27, 2008 8:32 PM
  • Chris,
    I don't know if this is the issue. Everything seemed fine. I checked event viewer and there were no error with certificate.
    I deleted certificate and select it again. Situiation looks like that. Do you think, I should recreate it (should go throu the hole process again)? IS there any way to check if everything is ok? Something like Validation on Front End Server?
    Tommorow morning I will try, if there is something new, aftwer deleting and reselecting certificate.
    Thursday, March 27, 2008 9:27 PM
  • Hi,
    This morning I tried: the same storry. I created new server with mediation role. Everything the same, except different IP. New server has IP Here you can see logs.
    Does anyone have idea, what is wrong with tls between mediation server and OCS. Is there any way, to check what is wrong?

    Friday, March 28, 2008 1:24 PM
  • Hi Rok,


    Sorry I cant be much help with this as I am not a certificate expert, but in saying that going by your logs it is the right area. You may want to do some logging from the front end to see what that server is seeing as well. Good luck.




    Friday, March 28, 2008 2:51 PM
  • Hello,
    I moved on with my problem. I solved my problems witch certificates. It was problem witch certificate. My certificate was invalid. I solved this problem. I set numbers in following format (for OCS users) tel: 193. If I tried to call this number from CISCO, my Office communicator started ringing, but the call was not started. I think, problem was, that number is not in E.165 format. This format states that each number has to have +. Problem is, that CISCO cannot cal with +. I think, I have to find a way, how to fet plus to number when call come from cisco.
    Is there any way to use normalization rules for inbound call ou, are they used only for outboiund rules.
    How this problem is solved with other users that were able to sucesfully connect OCS and CCM?

    Thanks in advance.

    Tuesday, April 1, 2008 9:36 PM
  • Hello Rok and everybody here!


    Experienced same problem, not with Cisco, but Communigate Pro.

    The problem in my case was in From: field - in your case for sure too.


    Your case:




    Add Cisco FQDN to trusted servers - Front End Properties of Standart or Enterprise Pool, Host Authorization tab if you cannot manage certificate on Cisco. IP address already trusted as entered in Mediation gateway.


    Routing -> inbound to OCS


    quote> From: sip:540;phone-context=unknown@unified.si;user=phone (Cisco
    quote> To: sip:193;phone-context=SRC.SI@unified.si;user=phone  (OCS Mediation

    Ideal for OCS to work correctly - both directions:

    From: sip:+540@;user=phone

    To: sip:+193@unified.si;user=phone


    Target - no problem!


    If INVITE & To are like 


    you will get the call in the right way if you have a normalization rule in dial plan like this for example:

    Phone regular expression: ^1(\d{2})$ - starts with 1, 3 digits total

    Target regular expression: +1$1

    Note, that OCS users line uris entered as tel:+193


    So, absence of "+" in INVITE & TO is not the problem! I far as I understood; only digits matter...


    Source - problem stays.


    If it will be:

    From: sip:540@unified.si;user=phone

    sended by Cisco and translated by OCS Mediation to:

    From: sip:540;phone-context=unknown@unified.si;user=phone

    when you most probably will be able to talk, but will not be able to forward to external (back to Cisco), simultaneous ring and double click on recent contacts list to call. Also call may fail if PSTN integration is enabled for user.


    Routing -> outbound from OCS


    On D-Link FXO gateway I've fixed this problem by entering extensions with "+" prefix, but most vendors deny entering non digits in extensions names...

    So if Cisco does not understand incoming "+" prefix in Invite and To, you may have also problem with routing FROM OCS, but in most cases it solvable - incoming routing is fully configurable on most servers-gateways.


    In my case From field with ;phone-context=unknown@ cannot be processed by server at all and INVITE is dropped before further processing.


    This is a compatibility issue between strict RFC & E.164 implementation (Microsoft) and tolerance of other vendors.

    If Cisco can rewrite From: field contents, then most probably you will fix the "misunderstanding" issue...




    1. Of course, simple additional SIP proxy only for rewriting SIP fields may fix the issue...


    2. If not - this is only a legal problem - you'll need to patch one of the software suites - in your country it can be illegal.


    Patching OCS, for sure, does not comply with Microsoft EULA so I cannot give here the description & strongly discourage such a solution... 


    I've contacted both Microsoft & Communigate, waiting for response, Microsoft less probably will fix the issue, see my post at http://forums.microsoft.com/unifiedcommunications/ShowPost.aspx?PostID=3206207&SiteID=57 why.


    Good luck!



    Sunday, April 20, 2008 2:44 AM
  • Hi all,


    The best way to integrate Cisco and Microsoft environments is to use and ISR configured as an IP-IP GW. This helps with the issue of the +. Connecting a Cisco Callmanager directly via a SIP trunk to OCS is not a supported configuration but the IP-IP GW configuration soon will be.

    There is a detailed discussion in this thread with configuration examples:




    Tuesday, April 22, 2008 2:53 PM

    Same problem...


    I understand, that we all here try to make a marriage of concurrents...

    But this is a real world task!


    Can not check the Cisco - but if you are sure, that it will be able to rewrite FROM field - you got your solution.

    Generally speaking, nothing difficult in implementation - simple SIP proxy (no rtp)

    Standart sip proxies tend to route TO (destination) perfectly, but do not manage FROM!


    But using hardware or software solution only to fix different standard implementation ...


    To clear the situation - it is EASY to make it working and solve the problem but illegal!

    + patching software makes vendor updates difficult.


    Waiting for next steps of Microsoft or Cisco...

    Writing SIP rewriter...


    Wednesday, April 23, 2008 1:41 AM