This level of architecture is defined in the common approach to Federal Enterprise Architecture Framework and focuses on services (and associated systems) that serve the entire Executive Branch of the U.S. Federal Government. These Federal-wide mission and support services are channelled through OMB-designated “Line of Business” providers, wherein the roles of provider and consumer are detailed and a comprehensive business model for each Federal-wide service generate requirements for that architecture.

Source: See Federal Enterprise Architecture Framework (common approach - as explained in Collaborative Planning Methodology).