Last week I started writing about inexpensive methods of deploying Microsoft's unified communications (UC) technology ("Inexpensive Unified Communications Deployment, Part 1," November 8, 2007). I recommended downloading the free trial versions of Exchange Server 2007 and Microsoft Office Communications Server (OCS) 2007 to get started, and I mentioned that Exchange unified messaging (UM) can use either a full-blown IP PBX (provided it's compatible) or an FXO/FXS gateway. It turns out that you can deploy OCS 2007 with the same setup, but first you have to answer an important question.

That question, simply put, is whether you want to deploy voice capability at all. There's no question that software-powered VoIP is one of the coolest features across Microsoft's entire product line, and I don't think that Microsoft's projections of potential cost savings and productivity increases are exaggerated. However, I'm reminded of the old saying about learning to crawl before you learn to walk. In my conversations with Exchange administrators around the world, one clear theme that I've heard is that enterprise VoIP seems complicated and scary.

The truth is that OCS 2007 isn't really more complicated than Exchange; as Jim McBee observed, it's just that OCS is different from Exchange, a product that most of us have gained a deep understanding of over the years. As with Exchange, OCS is very easy to deploy and manage if you have only a single server. It turns out that a single server might be all you need: The Standard Edition of OCS 2007 can handle 4000-5000 users on a single, suitably sized server, and the presence, IM, conferencing, and voice features can all run on that server. You will, however, need to add OCS's Access Edge Server role on a separate computer if you want to let users outside your firewall access those features, and you'll need to move to the Enterprise Edition of OCS 2007 to provide high availability.

The simplest, least expensive deployment option is to roll out a single OCS 2007 Standard Edition server for conferencing, presence, and IM, and to ignore voice altogether. If you're interested in voice functionality, you have two choices: - Without adding anything, you can use Microsoft Office Communicator 2007 or supported hardware devices such as the Polycom CX line to place calls to other OCS users. - By adding an OCS Mediation Server and an appropriate gateway, you can make OCS 2007 interoperate with traditional PBX systems and with the worldwide telephone network.

The OCS Mediation Server provides the glue that links whatever gateway or PBX you're using to OCS. As with Exchange, you can start with a simple 2-port FXO/FXS gateway. In conjunction with Exchange UM and OCS, this setup gives you the ability to have UM answer calls (including automated attendant support if you like), as well as the ability to have inbound calls ring a Communicator client. You can also place outbound calls with Communicator or other OCS-hosted devices.

This setup loses some functionality compared to a complete PBX system. For example, your ability to transfer calls is somewhat limited. However, you might be surprised at what you can do. For example, you can have an Exchange automated attendant answer the phone, then use dial-by-name to transfer calls to a Communicator endpoint. For a lab (or even a small business or home system), this level of functionality is perfectly fine.

Now for something completely different: I had breakfast with Hewlett Packard's Kieran McCorry at Microsoft Exchange Connections last week, and we came up with a great contest idea: We want to hear your horror stories about the worst Exchange design or administrative mistake you've ever seen—or committed! Submit your entries via email to update@robichaux.net by December 15; 2007, and we'll pick the five worst and publish them, omitting the real names of the guilty if requested. We have some fabulous prizes, including fully licensed copies of OCS 2007 Standard Edition and spiffy Windows IT Pro.