With Exchange, Unity’s key to servicing subscribers is through MAPI. That includes its use of a MAPI profile and system mailbox that is used to address messages from outside callers to subscribers of the system. The system mailbox also provides notification services for subscribers by monitoring their mailboxes for new messages and filtering on new voice messages. It basically monitors the state of all messages in a subscriber’s mailbox so that it can act upon the state appropriately.

Unity’s use of Domino is based on the Notes API; it uses the Lotus Notes client to access the Domino directory and messaging system. Through the Notes client, Unity provides unified messaging services to all subscribers. The implementation is a little different than in the Exchange version. This is largely the result of DUCS, which is in place to provide end-user proxy services for outside callers and to deliver messages to subscribers. The DUCS client provides a media master control for playing back and recording messages.

Unity was an early adapter of Telephony Application Programming Interface (TAPI) and made use of it for both its original voice board interface and its interface into CallManager. It uses TAPI through the telephony service provider (TSP), which is the interface connected to the voice board or CallManager. The early voice board manufacturer used by Unity was Dialogic and is still in use today.

Unity’s implementation into CallManager became more scalable and capable when it began using the Skinny Station Protocol in its TSP to connect to CallManager.

Along with Unity’s support of multiple integration types, the Unity 4.0 offering includes a TAPI-independent implementation of the Session Initiation Protocol (SIP). In the future, the next-generation replacement of legacy voice boards used by Dialogic includes SIP as its primary interface. Unity will integrate with this interface for Dialogic. In addition, Unity can support third-party SIP proxy servers from different vendors.

A couple of very important chapters focus on these integration technologies: Chapter 6, “Components and Subsystems: Telephony Services,” and “Chapter 17, “Unity Telephony Integration.” In addition, you will find switch file settings in the appendix.

This chapter discusses the challenges associated with unified messaging as a part of the voice data convergence paradigm for the messaging application layer. It recommends that you pay equal attention to organizational alignment as to the technical aspects of migrating to a unified messaging system. It highlights several ways to address the different issues that the unified messaging paradigms present to organizations that are interested in adapting unified messaging as their strategic direction. It also discusses other important issues, such as how to prepare for unified messaging both technically and organizationally. Finally, it covers topics that end users might be concerned about as well, such as privacy and security.