The epSOS architecture is based on a service-oriented paradigm. The epSOS services are passive and implemented as Web Services whose interfaces are specified by the Web Service Description Language [W3C WSDL 1.1]. Communication between service consumer and service provider is always initiated by the service consumer. Each Participating Nation (PN) provides these services through the National Contact Point (NCP) that acts as a service provider to other PN’s and as a gateway for service consumers.

The NCP is made up of a set of Common Components.

The epSOS Common Components provide the following end-user services when connected to the national infrastructure of the patient’s home country (“Country A”):

• Identification Service
• Patient Service
• Order Service
• eDispensation Service
• Consent Service

The NCP encompasses the following internal services for achieving semantic interoperability:

• Taxonomy manager
• Terminology Service Access Manager

In addition, the NCP provides auditing and authentication services.