Re: What is the difference between Microsoft & Cisco OCS?
Microsoft has a product named Office Communications Server (OCS) and it is the foundation for their VoIP strategy. If you have a pure Microsoft environment, you would add OCS to enable telephony functions. You would add MOC (Microsoft Office Communicator), basically a softphone and/or call control agent and OCS would enable you to set up voice calls to other members of your domain, regardless of physical location. To interface to the Public Switched network, you would have to add a "media gateway server" that would get you off your network and on to an attached PBX or telephone company line. OCS would also support SIP phones etc. CISCO UCS or Unified Call Manager is a VoIP PBX. It can interface to OCS through a media gateway via a SIP trunk. Some PBX system support direct attachment to the Microsoft Media Gateway and others, like ShoreTel, do not currently directly attach and would require yet another media gateway to mediate the SIP tie line between the OCS media gateway and the VoIP PBX. The CISCO solution is currently cleaner as it relates to interfacing with OCS.
The alphabet soup can drive a grown man to drink, but I think the above nets it out.