1. Architecture and Service Oriented Architecture
The shared service domain is actually a sub-domain inside IT. We cannot expect all functions in IT should be shared. Similar, the Service Oriented IT Architecture is in a sub-domain of IT architecture. The necessity of making a function to be a service only when it has potential to be shared and reused by multiple service consumers. The following figures illustrate the shared service domain inside IT domain and the service oriented IT architecture inside IT architecture domain.
Figure 3. Apply ITIL to the IT Operating Model based on the IT Operation Reference Framework
In conclusion: A Service Oriented IT Operating Model should be rooted on a Service Oriented IT Architecture, which has to be custom built for each individual IT organization based on its service requirements, responsibilities, and operating environment, though best practice reference can be helpful. Each IT operation is forming an ecosystem of its own, which needs insight, creativity, and systematic discipline to figure out the best operating model and to clear the way for its execution.