Sun Java System Communications Services software is flexible, open, and future-proof. It is based on open standards such as the Internet Message Access Protocol 4 (IMAP4), Post Office Protocol 3 (POP3), Simple Mail Transport Protocol (SMTP), Simple Network Management Protocol (SNMP), Short Message Service (SMS), and Lightweight Directory Access Protocol (LDAP). Sun's commitment to open standards is not just lip service. Several of the authors of these core Internet standards work for Sun and continue to contribute to the standards process.
Sun Java System Communications Services software also runs on a variety of operating systems, including the SolarisTM Operating System (SPARC® and x86 Platform) and Linux. In addition, it has well-documented APIs for extension and customization of messaging, calendaring, and instant messaging services. These published APIs and open standards make Sun Java System Communications Services software highly integratable with other enterprise applications, and facilitates migrations and upgrades of Sun Java System Communications Services products. In fact, the migration and upgrade costs of Sun Java System Communications Services software is less than 20 percent of that for Microsoft or IBM Lotus, according to a recent comparative study. [Messaging Total Cost of Ownership 2003 in Enterprise and Service Provider Environments, The Radicati Group, March 2003]
Microsoft Exchange, like most other Microsoft products, is highly dependent on proprietary technology, such as MAPI. In addition, Microsoft is introducing new proprietary protocols in the short term, such as WebDAV. Microsoft Exchange leverages Microsoft's proprietary MAPI protocol and Active Directory, and only runs on Microsoft Windows. By committing to Microsoft Exchange, an enterprise is also committing itself to a Microsoft Windows-based operating system and developmental platform that might be difficult to integrate with non-Microsoft applications. Many corporate customers have grown weary of being locked into Microsoft's proprietary product strategy and the way it places them at the mercy of Microsoft's upgrade schedule. This schedule often involves a complicated and costly architectural overhaul every few years. Many Microsoft customers are seeking alternatives.