Cisco UC v4/5/6 supported for Direct-SIP with OCS R2

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The UC Open Interoperability Program has been updated and Cisco Unified Communications Manager (aka Call Manager) versions 4, 5 & 6 are now supported for Direct-SIP connectivity with OCS R2.

This means that back-end integration can be configured between Cisco UC and OCS without the need for a gateway, and without requiring multiple client applications or softphones to be installed on the desktop.

Office Communicator can make/receive phonecalls using Cisco UC as a “PSTN gateway”, but without the need for client plug-ins which can cause version incompatibilities.

So mobile/remote users get the advantages of software-based wideband audio/video/conferencing with VPN-less access via the OCS Edge Server (without requiring an ASA or the associated remote-client licences), and people at their desk can still use their Cisco “hard-phones”.

 

IP-PBX Vendor Tested Product Supported Configuration Software Versions Tested OCS 2007 R2 OCS 2007
Cisco Cisco Unified Communications Manager Direct SIP 4.2(3)_SR3a

      4.2(3)_SR4b  
      5.1(1b)
      5.1(3e)  
      6.1(1b)
      6.1(3a)  

Known Limitations:

  • The PRACK message sent by CUCM 4.2(3) is malformed by missing the MAXFORWARDS header.  As a result, this configuration requires PRACK to be disabled.  By default, PRACK is disabled in CUCM 4.2(3)
  • For Office Communications Server 2007, this support requires update package for Communications Server 2007 Mediation Server: August 2008 .
  • OCS 2007 may not appropriately normalize the PAI in the 200 OK or UPDATE, resulting in OC displaying a non RFC3966 formatted global number and in failed RNL on OC. When calling from OC 2007 to a Cisco phone number, after the caller gets connected, the name of the person on the Cisco phone may not be shown on Communicator, and instead OC may display the E.164 number (without a "+") for the person on the Cisco phone. This is resolved in OCS 2007 R2
  • When calling from OC 2007 to a Cisco phone number, where the Cisco extension is disconnected or out of service, the Cisco IP-PBX may not notify OC 2007 in a timely manner. This has been remediated in OCS 2007 R2.

 

More information and updates at https://technet.microsoft.com/en-us/office/bb735838.aspx#direct, and example configuration for Call Manager 4 at https://communicationsserverteam.com/archive/2008/09/30/302.aspx