Microsoft has used web services to mimic RPC (remote procedure calls). You ask for an "object" from a web service, and what you get back provides the public interface to an object running on the web service's server. You can interact with that object, calling methods and examining or setting properties. In this model, web services allow an object on the server to expose program logic to clients over the Internet. Clients call exposed methods on the web service using standard Internet protocols. Typically, both ends of the connection communicate using SOAP messages (see the sidebar "SOAP"), which consist of self-describing, text-based XML documents.[*]
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