Enterprise Application Integration

Today's business applications rarely live in isolation. Users expect instant access to all business functions an enterprise can offer, regardless of which system the functionality may reside in. Enterprise Application Integration combines separate applications into a co-operating federation of applications, which work together seamlessly, providing the user with the functionality he needs without letting him see the undercurrents of the process, such as data routing and conversion, communication issues and so on.

Two logical integration architectures for integrating applications exist: direct point-to-point connections and middleware-based integration.

Direct point-to-point connections is easy to understand and quick to implement, when you have only a small numbers of applications to integrate. However, due to the high coupling between any two adjacent components, such an architecture is very hard to extend and may lead to redundancies.

Middleware-based integration takes the problem to a more abstract level by providing an intermediate layer which takes care of the mediation between applications. The middleware is essentially a generic interface which the applications use to communicate, without being aware of each other's specifics. Thus the problem of adding a new application reduces to modifying appropriately the interface, without affecting the other components.