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Benefits of using Microsoft OCS with Exchange 2007 Unified Messaging

Enhance Exchange 2007 and Microsoft Office Communications Server (OCS) unified communications features for missed call and call forwarding notifications.

At an architectural level, Microsoft Office Communications Server 2007 (OCS) and Exchange 2007's Unified Messaging (UM) Server role are both similar and complementary. Running OCS with Exchange Unified Messaging (UM) can enhance unified communications features in several ways, such as:

  • Allowing access to voicemail from the Communicator 2007 client
  • Enabling access to Outlook Voice Access (OVA) from the Communicator 2007 client
  • Receiving missed call notifications in both Outlook 2007 and the Microsoft Office Communicator 2007 client

Although using them together provides a more comprehensive messaging solution, Microsoft never specifically stated that both Exchange 2007 and OCS run concurrently to reap all their benefits. This changed with the release of Exchange Server 2007 Service Pack 1 (SP1), which contains enhancements to the UM role.

New dial plans

Office Communications Server uses SIP URI and E.164 dial plans, which Exchange Server 2007 didn't support previously. SP1 gives you the ability to create E.164 and SIP URI dial plans using Exchange Server's Dial Plan Wizard.

Intelligent call forwarding notifications

When Exchange 2007 and OCS are combined, some strange things can occur. For example, suppose that User 1 places a call to User 2, but User 2 forwards calls automatically to User 3. When this happens, Exchange gives User 1 the chance to record a voice message, and then places that message into User 3's mailbox.

More on unified messaging and Exchange Server 2007:
How Microsoft Office Communicator enhances Outlook 2007 functionality

Exchange 2007 prerequisites and custom server role installation

New unified messaging features in Exchange 2007 SP1

However, depending on the greeting that User 3 has on his mailbox, User 1 may think that he left a message for User 2. SP1 changes this. If User 1 places the call from the Office Communicator client, they are notified that they're leaving a message for User 3, not User 2.

Missed call notifications

Before the release of Exchange Server 2007 SP1, missed call notifications were messy in organizations running both Exchange 2007 and OCS because both products generated missed call notifications independently. If a Unified Messaging-enabled user is also using the Office Communicator client and misses a call, both the Office Communicator client and Exchange would generate missed call notifications.

Unless a user understands how the system works, they might think that they missed two separate calls. Exchange 2007 SP1 corrects this issue so that when Exchange and OCS are both in use, UM-enabled users also using the Office Communicator client will receive only one missed call notification.

Although most new unified messaging features in Exchange 2007 SP1 require OCS, some are available without OCS, including:

  • SRTP protocol support
  • The ability to configure TLS through the Exchange Management Console (EMC)
  • QoS support through DiffServ
  • Inband fax tone detection

About the author: Brien M. Posey, MCSE, is a four-time recipient of Microsoft's Most Valuable Professional Award for his work with Windows Server, Internet Information Server (IIS) and Exchange Server. Brien has served as CIO for a nationwide chain of hospitals and healthcare facilities, and was once a network administrator for Fort Knox. You can visit Brien's personal web site at

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