We are currently reviewing our catalogue of IT & Library services. In this, we follow ITIL, the widely used framework for service management. This has stimulated some discussion about how enterprise architecture can support service management, and also how the two approaches fit together.
In my opinion, EA best supports service management by providing context and describing how the various services inter-relate. An ITIL service catalogue is simply a list of services (in much the same way that an EA interface catalogue is just a list of APIs). The catalogue does not show how the services fit together, or which business capabilities they support, or which group of users uses each service. ITIL classifies services along one axis as “business services” or “IT services”, and along another axis as “customer-facing services” or “supporting services”, but these are broad-brush terms and open to interpretation.
An architecture diagram can show, for example, that one IT service is “customer-facing” from the point of view of the IT department because it supports “customers” in the Finance department, and that from the Finance department’s point of view the same service is a supporting service that underpins some aspects of one or more of their business services. The notion of “customer” changes depends on who is looking (in architecture, this is called the “viewpoint”). To continue the example, the finance services may have different customers – one may help students manage their accounts, while another may be for school administrators to manage their internal budgets.
The picture is a conjecture of how we could model this interrelationship for a subset of services. It shows, in the lower layer, two services provided by a production management group. These keep the IT applications running. One thing to note is that individual applications are not services; they only become services when grouped and managed.
The upper layer shows two groups that use these IT services to provide services to various groups of users. At Edinburgh, the Digital Learning section is part of Information Systems, as is Production Management, while the Finance section is in a different support group. EA shows that we can use the same model for internal and external customers, and provides a level of clarity that a simple catalogue cannot achieve.