Service Oriented Architecture/Enterprise Service Architecture
SAP SOA[Service Oriented Architecture]:
It is an architectural software design strategy in which there is a service provider and many service consumers. It is quite similar to the distributed computing principle. It is an idea of creating composite applications using open standards like WSDL, SOAP, Web Service. The service provider registers the service over UDDI in the form of WSDL and the service consumer looks/searches for the UDDI of the service and invokes it.
A service is a function which is well defined, self-contained and doesn’t depend on the context of other service. SOA is a collection of services that communicate with each other. The communication is initiated by a service consumer which sends a request to the service provider and the provider sends back a response message to the service consumer. The request and response connections are defined[in terms of web service] such a way that which is understandable by both provider and consumer.
SAP ESA[Enterprise Service Architecture]:
It is more specialized/enhanced version of SOA . It is an open architecture for adaptive business solutions. Enterprise services means a standard way of encapsulating enterprise functionality and exposing as a reusable service that can be combined with other services to meet new requirements. Different enterprise services can be assembled together to frame a new application or new composite business process.
Enterprise services are implemented as web services where interfaces are defined using WSDL files. There are 2 approaches followed to design services.
- Outside-In: which means analyzing the business process to be automated and then designing/constructing the service.
- Inside-Out: which means creating a service from the existing functionality.
It is an interface which implements the industry standards of SOAP & WSDL to expose a service to the service consumer. Its a technical implementation of exposing a service using standard based protocols.