Enterprise application integration (EAI) is the use of software and architectural principles to bring together (integrate) a set of enterprise computer applications. It is an area of computer systems architecture that gained wide recognition from about 2004 onwards. EAI is related to middleware technologies such as message-oriented middleware MOM, and data representation technologies such as XML. Newer EAI technologies involve using web services as part of service-oriented architecture as a means of integration.

Without integration, enterprise computing often takes the form of islands of automation , where the value of individual systems is not maximised because they are working in partial or full isolation. However if integration is carried out without following a structured EAI approach, many point-to-point connections grow up across an organisation. Dependencies are added on an ad-hoc basis, resulting in a tangled unmaintainable mess, commonly referred to as spaghetti.

Current thinking is that the best approach to EAI is to use a message bus to connect numerous separate systems together. Other approaches have been explored, connecting at the database level or at the user-interface level, however, the message bus approach has generally been adopted as the strategic winner. Individual applications can publish messages to the bus, and also subscribe to receive certain messages from the bus.

With EAI each application only requires one connection, which is to the bus. Attending to EAI involves looking at the system of systems. Such message bus approaches can be extremely scalable, and also highly evolvable.

EAI is not just about sharing data between applications. EAI focuses on sharing both business data and business process.

EAI Appliances

Cast Iron Systems's Application Router

EAI software

• IBM's WebSphere MQ
• Frends Technology 's EAI Platform
• SeeBeyond e*Gate
• Fiorano Business Integration Suite
• TIBCO Active Enterprise
• Webmethods Integration Suite
• WISTE C GmbH, Germany
• Microsoft's Biztalk
• BEA Systems's WebLogic Integration 8.1
• Impress Software 's Impress Engine
• Sonic Software 's ESB (Enterprise Service Bus)
• Vitria BusinessWare

External links

• Enterprise Application Integration (EAI) reports, white papers and case studies
• Integration Consortium
• Enterprise Integration Patterns
• IBM Patterns for e-Business (includes section on integration patterns)
• Microsoft Patterns and Practices (includes section on integration patterns)
• Cast Iron Systems .