The service catalog is a customer-oriented description of the services provided by the IT department / service department to the user.
By using the service catalog, the department can change focus from delivering technical solutions to the delivery of functionality. This provides a closer link to the business, by identifying and focusing on the services the department delivers to the business. At the same time, you will establish a common language that both the department's employees and users can relate to.
There are many different supporting components / objects that make sure the service is working properly. By associating service objects to the More Service cases, you get an overview of how the department delivers according to user needs. And user's needs are the basis for the delivery!
When service objects get relationships / dependencies to other supportive objects, it's easy to see what the service contains of and which customers are affected:
Or this way: