Bringing communications together
Email used to be fairly straightforward. When implementing email technology, your major challenge was to ensure interoperability between different email systems. But once you achieved that interoperability, you could sit back, content in the knowledge that users could send messages to each other without hindrance.
Email is different today. More means of communications exist, more points of access are available, and more content types exist. If we used a separate device for each type of communication, our systems would resemble warriors with devices slung from every available patch of combat webbing. If this vision seems ridiculous, think of how many devices you take on a business trip: cell phone, pager, notebook PC, and perhaps a palmtop for quick access to notes and phone numbers. Wouldn't you like to have one seamless system that had multiple points of access through a range of different devices?
Unified messaging is a hot topic today. Maybe it's the answer that will help us make more sense of information overload. When senior Microsoft executives discuss their plans for Platinum—Exchange Server's next major functionality release, due in 2000—and for the Windows 2000 (Win2K) platform in general, they talk about unified messaging. This article discusses Exchange Server 5.5's current state of voicemail integration and looks at how messaging will evolve when Platinum and Win2K hit the streets.
What Is Unified Messaging?
Unified messaging is a much-abused term, so I want to define it in practical terms. Unified messaging provides anytime, anywhere message access—via telephone or other communications devices—to one location (the Inbox), which can contain email messages (and the variety of attachments they transport), voice messages, faxes, Short Message Service (SMS) messages, pager messages, and so on. To some degree, you can unify communications around your Inbox today, but the range of devices that can currently access and interact with your Exchange server's Inbox is limited. Microsoft's goal is to expand the range of useful devices in Platinum.
Exchange Server's original vision was information exchange, and Microsoft designed the server from the start as a platform for messages containing both voice and data. However, the majority of information that Exchange servers process today remains text-based, although fax integration through connectors is fairly common. Connectors have extended Exchange Server's reach in terms of the number of systems the messaging system can communicate with, but users haven't really moved beyond viewing Exchange Server as simply an email server.
Unified messaging solutions extend a standard email server to support different types of communication. Voicemail integration is the most popular and available unified messaging solution today. Figure 1 illustrates a typical unified messaging solution. Software layered onto a PBX captures voice messages and translates them into a format that the email server can understand. In an Exchange Server environment, the Telephony API (TAPI) is the software layer between the PBX and Windows NT. The Messaging API (MAPI) translates voice messages for Exchange Server, which delivers the translated messages to users' Inboxes. Users can then play the messages over a desktop PC's built-in speakers. However, you need to use a client that can understand the voicemail format. Microsoft Outlook and the original Exchange client—which only Exchange Server 4.0 and 5.0 provided—can play messages if you've installed a custom form, but POP3 and Internet Message Access Protocol 4 (IMAP4) clients such as Outlook Express can't. Nor can you use the Outlook Web Access (OWA) browser connection. You can, however, extract voicemail attachments and play them as you would play standard voice files.
Still a Rarity
In the right environment, the current generation of voicemail products works well and delivers some of the vision of unified messaging by integrating voice and fax with email. But unified messaging is still a rarity in Exchange Server installations. The following are some reasons why Exchange Server hasn't moved forward toward Microsoft's original vision:
- the perceived cost of extending Exchange Server in terms of software licenses (for the unified messaging software) and additional hardware
- the relative lack of API access to the Exchange Server 5.5 messaging engine
- the relative immaturity of the unified messaging space
On the surface, extending Exchange Server with any third-party product incurs license fees and probably increases hardware demand to the point at which the hardware requires some kind of upgrade (e.g., CPU, memory, hard disk). Software vendors need to generate a return on their investment. And even though the Exchange Server marketplace has reached more than 25 million seats (at the end of second quarter 1999), add-on sales for unified messaging haven't reached a volume comparable to that of more popular extensions such as virus checkers, fax connectors, management tools, and backup products.
Some companies, including Microsoft and several independent consulting firms, maintain that a unified messaging solution's cost is cheaper than the cost of deploying voicemail and email on separate platforms. I suspect that these companies' requirements and infrastructures vary so much that such a sweeping generalization—unified messaging will be cheaper for you—is impossible. Understandably, Microsoft advocates unified messaging built around Exchange Server, as outlined in a white paper available at http://www.microsoft.com/exchange/km/um.htm.
The relative lack of APIs for Exchange Server increases development costs and eventually increases license fee costs. MAPI is a comprehensive API, but it has limited access to the Information Store's (IS's) contents. Applications must mimic a mailbox to interact with the IS, or vendors need to write clientside extensions to process new types of data, such as voicemail messages. Direct access to other Exchange Server components such as the Message Transfer Agent (MTA) and connectors doesn't exist, so applications need to channel everything through the IS route.
Microsoft extended Exchange Server 5.5's Directory Store by adding a set of voicemail attributes that make the Directory Store more attractive to integrators. The attributes, which the Directory Store holds on a per-mailbox basis, include voicemail greeting, voicemail password, voicemail recorded name, voicemail user ID, and so on. Exchange Server doesn't inherently use these attributes, so developers can decide what to do with them. You don't have a client user interface (UI) to view the voicemail attributes, so you need to run the Exchange administration program in raw mode to see them, which Screen 1 shows. You can't currently customize the Directory Store to meet specific application requirements, so out-of-the-box attributes are a welcome development. Otherwise, developers would have to store this data in another custom directory. Win2K's Active Directory (AD) offers a totally extensible schema, so developers will have the freedom (within reason) to add their own voicemail attributes to the directory.
Advances in hardware capabilities have had much influence in this arena. Faster desktop clients can process voicemail messages more smoothly, and faster servers equipped with multiple CPUs and better disk subsystems can store and provide large voicemail attachments more smoothly to clients.
What's Available Today?
Two types of voicemail integrations are available for Exchange Server deployments today: server-centric and client-centric. A server-centric integration delivers voicemail to Exchange Server Inboxes the same way it delivers email. Architecturally, bringing everything together on a common server presents the most seamless and attractive solution. Microsoft emphasizes the server-centric approach in Exchange Server, which can process multiple message types. Future enhancements to the Exchange Server platform will make this type of unified messaging far easier to engineer.
Lucent Technologies' Unified Messenger (http://www.octel.com/um) is well integrated with Exchange Server. Unified Messenger, which you manage through the Exchange administrator program, uses the IS to hold its voicemail and fax messages and lets you address new voice messages via the Global Address List (GAL). Lucent demonstrates impressively what you can do today to exploit Exchange Server as a unified messaging platform. If you're looking for an integrated solution, Unified Messenger deserves serious consideration.
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