A few days ago I referenced Mary Beijleveld's post on the Approach Alliance blog, in which she offers a high-level explanation of IT architecture by comparing it to building architecture. Rajesh Raheja's recent post on The Official AIA Blog takes the shopworn Lego(tm) metaphor for SOA to task, and in the process provides an excellent drill-down that perfectly complements Mary's post:
Let’s put this in the perspective of SOA technologies. The general contractor is a BPEL Process, whose purpose is to orchestrate all the Services from disparate heterogeneous systems. The services in this example are the different actors – the concrete provider, foundation company, lumber company, framers, electricians, roofers, plumbers and painters. The contractor found the providers by searching the Yellow Pages (UDDI) and found the phone listing (WSDL); communicated by voice (XML) over the phone (standards based Web Service) in English (Standardized Semantics). He got quote and availability information, without having to really understand much about the inner workings of the concrete business (Service Abstraction), and as long as the provider abides by the contract, the contractor does not care who the actual electrician is (Service Virtualization).
Read Rajesh's entire post: The World of SOA: Laundries, Legos, and Home Construction (The Official AIA Blog)