Enterprise Service Bus

An enterprise service bus (ESB) implements a communication system between mutually interacting software applications in a service-oriented architecture (SOA). It implements a software architecture as depicted on the right. As it implements a software architecture for distributed computing, it therefore also implements a special variant of the more general client-server model. Whereas in general any application using ESB can behave as server or client in turns. ESB promotes agility and flexibility with regard to high protocol-level communication between applications. The primary goal of the high protocol-level communication is enterprise application integration (EAI) of heterogeneous and complex landscapes.

The concept is analogous to the bus concept found in computer hardware architecture combined with the modular and concurrent design of high-performance computer operating systems. The motivation was to find a standard, structured, and general purpose concept for describing implementation of loosely coupled software components (called services) that are expected to be independently deployed, running, heterogeneous, and disparate within a network. ESB is also a common implementation pattern for service-oriented architecture.

An ESB transports the design concept of modern operating systems to networks of disparate and independent computers. Like concurrent operating systems an ESB caters for commodity services in addition to adoption, translation and routing of a client request to the appropriate answering service.

The primary duties of an ESB are:

There is no global standard for enterprise service bus concepts or implementations. Most providers of message-oriented middleware have adopted the enterprise service bus concept as de facto standard for a service-oriented architecture. The implementations of ESB use event-driven and standards-based message-oriented middleware in combination with message queues as technology frameworks. However, some software manufacturers relabel their existing middleware and communication solutions as ESB without adopting the crucial aspect of a bus concept.

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