Rollout: Microsoft Office Communications Server 2007Rollout: Microsoft Office Communications Server 2007

SERIOUS SETUP
Don't expect to be up and running quickly. OCS requires as many as seven server systems to take advantage of VoIP, conferencing, and IM--more if you install a certificate server or reverse proxy. Servers include the director (also known as the front-end server), edge server, audio/video server, Web conference server, Web access server, archiving server, and mediation server.

At a minimum, OCS requires the director and edge servers. The director sits inside your firewall and is the primary server for OCS. It provides internal IM capabilities and talks to your domain controller to provide authentication. The edge server controls all external connections and federations with AOL, Yahoo, and MSN. It also federates with business partners that use LCS or OCS, letting you add people from federated companies directly to your contact list.

OCS comes in Standard, to handle as many as 5,000 users, and Enterprise versions. The Enterprise edition allows for more server pools, clustering, and a distributed environment, which some larger corporations may require.

Fair warning to small IT shops going it alone: It's easy to get confused as to what these various servers do and whether you need them. Invest some time with the manuals before clicking the install button. Larger organizations may want to consider engaging consultants.

There's also cost: Licensing starts at about $21 per user. Standard server licenses are $487 per year; Enterprise server licenses are $2,790 annually. It's not inexpensive, but Office Communication Server is an enterprise-ready unified messaging product, with integration and some presence management features unparalleled when compared with other products we've seen.