Understanding the Two Versions of Exchange 2003
Exchange Server 2003 comes in two versions (as does Exchange 2000): Exchange 2003 Standard Edition and Exchange 2003 Enterprise Edition. This is similar to the naming designations used for Exchange 5.5 and Exchange 2000. Typically, the Standard Edition is used for either a small organization or as a utility server in a large environment. The Enterprise Edition has more expandability for larger organizations or those organizations that need to take advantage of some of the advanced capabilities of Exchange.
Getting to Know the Exchange 2003 Standard Edition
The Exchange Server 2003 Standard Edition is the basic message server version of the software. The Standard Edition supports one mailbox database up to 16GB. The Standard Edition has full support for Web access, mobile access, and server recovery functionality.
The Standard Edition is a good version of Exchange to support a messaging system for a small organization, as a front-end server for a larger environment, or as a bridgehead server for an Exchange organization. Many small and medium-sized organizations find the capabilities of the Standard Edition sufficient for most messaging server services, and even large organizations use the Standard Edition for message routing servers or as the primary server in a remote office. The Standard Edition meets the needs of effectively any environment wherein a server with a 16GB database is sufficient.
NOTE
Unlike Exchange 2000, which required an Enterprise Edition version of the messaging system for a server to be a front-end server, Exchange 2003 can run on a Standard Edition version of the messaging system. By enabling an organization to acquire a Standard Edition license of Exchange, the licensing cost can be significantly lowered for organizations that split their back-end mailbox server from their front-end client access server.
Expanding into the Exchange Server 2003 Enterprise Edition
The Exchange Server 2003 Enterprise Edition is focused at server systems that require more than a single 16GB Exchange messaging database. With support for up to 20 databases per server, the Enterprise Edition is the appropriate version of messaging system for organizations that have a lot of mailboxes or a lot of mail storage.
NOTE
Typically, organizations implementing Exchange Server 2003 Standard Edition install the messaging system on top of Windows Server (2000 or 2003) Standard Edition. Choosing to install the Standard Edition of Exchange 2003 on top of a Standard Edition of Windows limits the organization's ability to migrate the server to the Enterprise Edition of Exchange. Although an organization may choose to upgrade Exchange to the Enterprise Edition, the organization would also want to upgrade Windows to the Enterprise Edition, making it a challenging task to upgrade the version of the Exchange license.
Table 1.1 summarizes the differences between the Standard and Enterprise Editions.
| Exchange 2003 Function | Standard Edition | Enterprise Edition |
|---|---|---|
| # of storage groups supported | 1 | 4 |
| # of databases per storage group supported | 2 (1 private, 1 public) | 5 |
| Maximum database size | 16GB | Unlimited (16TB maximum) |
| Clustering support | None | Up to 8-node |
| X.400 connector support | None | Included |
| OS support | Windows 2000 SP3+ or Windows Server 2003 Standard or Enterprise | Windows 2000 SP3+ or Windows Server 2003 Standard or Enterprise |