SOAP and WS-* originate from a more complex and heterogeneous domain, the one of enterprise computing. This domain can be characterized as a collection of heterogeneous, autonomous, distributed software systems [7]. In organizations having a long history, which may even predate the advent of the Web, these software systems are implemented in many different kinds of technologies. Examples are legacy COBOL programs running on mainframes that require screen-scraping, transaction processing over Message Queuing (MQ)-based reliable data feeds, and distributed object-oriented programs adhering to the Common Object Request Broker Architecture (CORBA).
From these examples, it can be seen that the heterogeneity addressed by WS-* standardization efforts goes beyond the synchronous client/server protocols used in specific RPC middleware products, but extends to delivering the interoperability needed to build the plumbing for SOAs integrating technically diverse enterprise applications.