The document discusses using the e-Framework and service-oriented modeling approaches to describe reusable infrastructure services. It presents the TARDIS crystallography dataset registry as an example. Service usage models (SUMs) are described as a way to break down functions into reusable blocks and model relationships between services, data sources, and other requirements. Composition diagrams are suggested to further specify how services operate on business objects and which parts of SUMs are involved. The benefits of taking a modular approach and describing services at different levels of abstraction are also outlined.