An enterprise service bus (ESB) is a key enabler for service-oriented architecture (SOA). This section shows some of the ways you can reuse your applications and services in a flexible and scalable way, using an ESB.
SOA is an architecture for building business applications from loosely coupled components, and for delivering a well-defined level of service.
Both WebSphere® Enterprise Service Bus (WebSphere ESB) and WebSphere Process Server provide ESB functionality that enables you to build SOA solutions.
The scenarios and use cases follow the IBM® service connectivity scenario (which is a scenario of use rather than a business scenario). The service connectivity scenario describes the way a middle tier (the ESB) provides routing and mediation, of messages passed between service requesters (consumers) and service providers. An ESB decouples the way a service requester views a service, from the implementation of a service. An ESB also decouples the business view of a solution from the technical aspects of service interactions; and allows integration and management of services. For more information on the IBM service connectivity scenario, see the: Service connectivity scenario.
The ESB pattern. An ESB is a high-level, architectural, pattern in its own right. The ESB pattern can involve several different roles. For example, adapter, hub, gateway and registry. Some products can perform more than one of those roles. Enterprise Service Bus and WebSphere Process Server can act as a gateway and a hub, and as an adapter. They use WebSphere Service Registry and Repository (WSRR) to provide the registry role.
Standard enterprise integration patterns. Individual interactions exposed by an ESB can use low-level design patterns such as mediation. Mediations are created in mediation modules, using WebSphere Integration Developer. WebSphere Integration Developer uses patterns, embodied in building blocks called mediation primitives. Mediation modules are deployed to the runtime product.
Patterns for e-business. An ESB can be part of a wider solution pattern. IBM provides e-business patterns that include ESB functionality.