NAF v4 enables you to build a business Service layer to the architecture. Most organizations use external Services to get things done, in addition to internal systems and resources. An example is running a Credit Check: a service-level agreement might specify what information is to be provided, how timely the information is, how secure it is, and so on. NAF v4 enables you to capture Service Specifications, Service Interfaces, and who provides those Services. The Service viewpoints are as follows: