This document establishes a Service Oriented Architecture (SOA) for the realization of interoperable web services for Intelligent Transport Systems (ITS).

Web service behaviour is described at the metadata level, i.e. a higher level of abstraction, to enable auto-generation of both a ‘service requester’ program as well as a ‘service provider’ program. Figure 1 presents the principal entities involved in a web service scenario. They are service provider, service requester, and 'registry'. The registry includes business information and technical information such as interface and policy. Figure 1 also depicts the actions of the service provider and the service requester. A service provider interacts with the registry to enable it to "publish" the provided service. The service is characterized in the form of a web service interface describer in the form of a standardized web service description language (WSDL) and policy (WS-Policy). A service requester interacts with the registry to "discover" a provider for the service he is seeking. That interaction takes place through "Universal Description Discovery, and Integration" (UDDI) dialogue and endpoint reference (EPR). Once the service requester identifies a service provider, he "binds" to the service provider via an SOA protocol.

This document is applicable to inter-ITS sector web services as well as ITS web services for non-ITS users.