If network architecture can be thought of as analogous to a framework, then facilities and services can be thought of as the bits and pieces that give the architecture detailed substance and a useful purpose. In communications networks, as in broadcast networks, there is an input and output the basic function. Both must be managed and their assets and cost of operation must be accounted for. Both are enabled with interfaces and protocols. Both tend to evolve and adapt to regulatory and technology forces. More importantly, those that respond favorably to market demand, survive, grow, and prosper.

This chapter is not about how to design and build a telecom network. The intent is to provide information about the nature and characteristics of networks sufficient to communicate desires and requirements to potential equipment and service providers using Internet and Telecom terms, standards, and symbols. The overall goal is to help the reader understand communications network architecture, facilities, and services. The secondary objective is to provide a framework with which to evaluate potential service provider s ability to deliver facilities and services capable of meeting their requirements, and ultimately assessing and measuring performance against the terms in a contract.