Microsoft made Release Candidate 1 (RC1) for Exchange 2000 Server available in late February. The arrival of release candidate-quality code is a significant milestone for any product because it marks the point that the developers think their work is approaching the end. Exchange Server 5.5 shipped in 1997, so the gestation of the latest version of Exchange has extended over \[Karen: "over" or OK?\] 3 years, and the amount of new technology and change incorporated into Exchange 2000 justifies the wait.

Release candidates force systems administrators to decide whether it’s worthwhile to install and test the new software. With Exchange 2000, I think the answer is a resounding yes. Here are six reasons I think you need to try Exchange 2000 now.

  1. Exchange 2000 is very different from Exchange Server 5.5.
  2. You can’t fully understand the differences in the two versions until you start playing with the new code and see how terminology, meaning, and functionality have changed. Microsoft has eliminated the old organizational structure, replaced the Directory Store with the Active Directory (AD), replaced the Message Transfer Agent (MTA) with an SMTP-based routing engine, added new cluster technology, and partitioned the Information Store (IS). Storage management has changed, too; you need to master new concepts such as storage groups that are feature rich but complex and the difference between the current .edb databases and the new streaming file that Exchange uses for Internet format data. You might understand these concepts as you read about them, but there’s nothing like seeing how the code works in real life.

  3. Exchange 2000 is totally dependent on Windows 2000 (Win2K).
  4. You might know that Exchange 2000 depends on Win2K, but you won’t know what this dependency means until you roll out the first Exchange 2000 server in a Win2K forest. Will Exchange’s schema updates be effective on all domain controllers? If not, your replication topology won’t work. Will Exchange be able to use DNS to route messages effectively? If not, you need to fix the problem before you think about a deployment for production. Outlook and other clients depend on Global Catalogs (GCs) for the Global Address List (GAL). What is your strategy for locating GC servers within your Win2K infrastructure?

  5. Exchange 2000 includes a new architecture.
  6. Exchange 2000 supports all previous Exchange clients, including the original Exchange Server 4.0 Capone Messaging API (MAPI) client. Exchange 2000 also includes a new version of Outlook Web Access (OWA), which introduces a new architecture to eliminate OWA's scalability bottlenecks. Microsoft didn’t base the new architecture on Active Server Pages (ASP) and MAPI, but on HTTP-DAV, Extensible Markup Language (XML), Extensible Style Language (XSL), Dynamic HTML (DHTML), and a direct memory-based connection (called epoxy) between Internet Information Services (IIS) and the IS. Not all browsers can leverage the full capabilities of the new architecture, but Internet Explorer (IE) 5.0 certainly can, and the combination of OWA and IE 5.0, which Microsoft refers to as its "rich browser client," delivers great functionality and more than acceptable performance. It’s definitely worth a look.

  7. Exchange 2000 offers new programming opportunities.
  8. In the past, few brave souls ventured into the world of server-side programming or wrote code that used the IS as a repository for application data because of the high learning curve required to master MAPI and the inadequacies of other interfaces such as Collaborative Data Objects (CDO). As a result, most systems administrators left Exchange extensions in the hands of professional developers, who created add-on products such as connectors and virus checkers.

    That situation might now change. Exchange 2000 supports a new version of CDO as well as ActiveX Data Objects (ADO) and OLE DB. The contents of the IS are open to programmers to manipulate through a variety of languages, from Visual Basic (VB) to C++. And the arrival of the Web Store means that every item in the IS gets a URL. Exchange 2000 provides the new Exchange Installable File System (ExIFS), which lets any Win32 program use standard file manipulation calls to read and write into mailbox and public folders. Exchange 2000 delivers Exchange Management Objects (EMO) to comply with the Windows Management Instrumentation (WMI) interface, and you can program EMO to deliver additional management or administrative functionality. Programmers have never had it so good in the Exchange world, and a few more brave systems administrators might take advantage of these new features.

  9. Early migration offers benefits. You must migrate from Exchange Server 5.5 some day. Planning for that migration now means that you can look at essential aspects such as mixed-mode Exchange, in which Exchange 2000 servers interoperate with Exchange Server 5.5, 5.0, or even 4.0 servers. You can also test synchronization between the AD and the Exchange Server 5.5 Directory Store.

  10. Exchange 2000 has a new administrative model. Exchange 2000's administrative model differs significantly from Exchange Server 5.5’s model. A set of Microsoft Management Console (MMC) snap-ins replaces the old monolithic Microsoft Exchange Administrator program. The Exchange System Manager snap-in is closest in function to Exchange Administrator. Administrative groups and routing groups replace the organizational model based on sites. Small organizations won’t notice the difference because they can continue to run Exchange 2000 as they do today. However, the changes are far-reaching and important for large and distributed enterprises, which need to review their current structures to see how the structures might map into the new organizational model.

The quality of the RC1 code is sufficient to perform a lot of solid testing. The product’s features are far more complete than those in the beta 3 release that Microsoft distributed at the Microsoft Exchange Conference (MEC) last October.

RC1 marks the start of the final lap in the race to ship Exchange 2000. The product will develop further along the way and have at least one other release candidate. If you haven’t already started, now is a good time to begin the planning process for the migration to Exchange 2000. The migration will require a lot of work to achieve a seamless upgrade. Knowledge acquisition is key to all migrations, especially when you must deal with a lot of new technology. Exchange 2000 contains a lot of new technology, so I recommend that you use the release candidates to get to know what Exchange 2000 is all about.