ften taught and thought of as being layered and linked. Layering breaks the network into a set of logically related components. Linking connects the com- ponents and makes up an end-to-end facility or service. The network becomes the link between all the equipment at all the locations making up the network. Successful use of network facilities and services always includes a set of common equipment at each location where facilities are terminated, enabling service delivery. Still, equipment, facilities, and services alone are insufficient to ensure successful busi- ness use. Man cannot live by bread alone; he must have peanut butter. The key ingredient required for success is a walking, breathing human being, qualified to be responsible and held accountable for making sure all the equipment, facilities, and services are configured, main- tained, and changed as day-to-day demands of the enterprise change. If you are a designer, manager, or senior staff responsible and/or accountable for making or approving decisions related to design, planning, and management of assets and operating expenses related to communications network asset and expense management, the material in this section is one of the more important, if not the most important, part in the book. It can be a technical foundation for a process whereby you and your organization can take firm control of communications equipment and service vendors by first defining your needs in their terms and lingo SO you can establish a competitive procurement environment as the first step in building a long-term mutually beneficial relationship between your organization and the vendors. You can benefit greatly if you take the time to study and understand the technical and economic aspects of how to order and piece together end-to-end facilities and services to build the network best suited to your business. The level of detail in this chapter is structured around the common equipment at each location and its interface to network facilities and 5 NETWORK ARCHITECTURE, FAC