Communication & Coordination
Modern thinking is to minimize the dependencies between units by maximizing their ability to manage themselves. In most organizations, the style and techniques of management used within a unit differ substantially to those used between units.
Management within a unit typically requires continuous scheduling, execution and evaluation of processes, allocation and re-allocation of resources, and ongoing refinement of its purpose. Management between units is by periodic coordination of mutual purpose, and communication of shared events. The primary need within a unit is for integration, typically by sharing information in a database, while that between units is for interaction, typically by exchanging messages over networks.
One unit cannot simply instruct another to perform a service since each is an autonomous entity. They must first come to an agreement about, and record in a contract, the terms and conditions under which the service is to be performed, and the means by which each is to be notified of appropriate events.