Explanation/Reference:
Web Services are a natural fit for building distributed computing platforms.
* WSDL, SOAP, and XML promote language and platform independence and interoperability.
* UDDI allows services deployed in a distributed infrastructure to be discovered and consumed.
* Simple Object Access Protocol (SOAP) enables service binding and invocation using standards based protocols such as HTTP and JMS.
* The platform for SOA should support the WS-* standards
Note: Openness is the property of distributed systems such that each subsystem is continually open to interaction with other systems. Web services protocols are standards which enable distributed systems to be extended and scaled. In general, an open system that scales has an advantage over a perfectly closed and self-contained system.
Reference: Oracle Reference Architecture, Application Infrastructure Foundation, Release 3.0