The ESB is a key enabler for a SOA as it provides the capability to route and transport service requests from the service requester to the correct service provider. The true value of the ESB concept, however, is to enable the infrastructure for SOA in a way that reflects the needs of today’s enterprise: to provide suitable service levels and manageability, and to operate and integrate in a heterogeneous environment.
Furthermore the ESB needs to be centrally managed and administered and have the ability to be physically distributed.