When Microsoft released Exchange Server 2007, one of the new features that received the most attention was unified messaging. Out-of-the-box unified messaging was certainly new to Exchange, but it wasn't Microsoft's first product to focus on unified communications. Long before Exchange 2007, Microsoft had created a unified communications product called Microsoft Office Live Communications Server (LCS). LCS was a nice first attempt at providing true unified communications capabilities, but it was really difficult to set up, and as with any first-generation product it was a bit lacking.
In 2007, Microsoft released a new version of LCS that was named Microsoft Office Communications Server 2007 (OCS). Like its predecessor, OCS was designed to be a full-featured unified communications platform, but it was still missing some features. As you may have already guessed, the features that OCS lacks have been incorporated into Exchange Server 2007. In fact, the two products were designed from the very beginning to be complementary and to integrate with each other.
An Introduction to OCS 2007
In my personal experience, OCS is, by far, the most difficult Microsoft product to deploy. The initial configuration process usually takes several hours to complete, and I have to admit that running the product for the first time after the installation completes is a bit anticlimactic. That's because on the surface, OCS seems like nothing more than an instant messaging server. Granted, instant messaging is nice, but OCS can be a bit of a letdown if you are expecting it to initially act as a comprehensive communications solution.
All is not as it initially appears, however. First, it's important to keep in mind that instant messaging is a type of communication, so it fits in perfectly with the goal of creating a unified communications platform. More importantly, though, a basic OCS deployment supports the use of presence information.
Presence is a very important part of any unified communications system. One of the problems with offering users so many different ways of communicating with each other is that it can become difficult to know how to contact a user. You don't know which communications method the user prefers, whether a user is available, or the best way of reaching a user at a given moment. Presence solves all of these problems by acting as a mechanism through which users can convey their availability status.
I'll be the first to admit that in a basic OCS deployment, the way that presence is used really isn't all that impressive. It's basically just used to tell users which other users are currently available for instant messaging chats. Even so, this presence information is extended as your unified communications deployment grows. When the full deployment process is complete, presence information becomes a definitive means for conveying if, when, and how users on your network can communicate with one another.
Another thing that I want to explain about OCS is that presence and instant messaging aren't the only capabilities that it can provide. In fact, OCS can be configured to allow users to make telephone calls from their PC. It also supports point-to-point videoconferencing and some other collaborative tools.
Although OCS 2007 clients can place and receive VoIP-based telephone calls from their desktop, OCS doesn't provide all of the calling features that most organizations would probably expect. The most obvious feature it lacks is voicemail. Of course, this is where Exchange comes into play. Exchange Server 2007’s unified messaging component allows voicemail and faxes to be received and stored in a user's inbox, alongside their e-mail messages.
Exchange Server 2007 also provides a feature called Outlook Voice Access (OVA), which is basically a telephone version of Outlook Web Access (OWA). This feature allows users to dial into the Exchange organization and check their calendar and messages over the telephone. OVA provides much of the same basic functionality that OWA provides, with the biggest difference being that users interact with Exchange over OVA solely through the telephone. You can configure OVA to accept verbal or touch tone input.