Focusing on integrated services digital networks (ISDNs), this work shows how to plan and design them architecturally and how to implement them so that they meet certain given user requirements ranging from a variety of service demands to transmission performance, security, reliability/availability, capability for growth, interoperability with other ISDN and non-ISDN networks, and cost. The book concentrates on the application of ISDN concepts and standards to the planning and design of real costed networks to meet certain specified user requirements. Where there are multiple options, considerations and rationale on the choice of network aspects and standards are discussed. It expounds a methodology which starts from an assumed or given set of complete user requirements, and proceeds to the designing of a complete network taking into account the technology and standards of ISDN, as well as some constraints which may be imposed, including cost. The book is intended as a comprehensive reference source which is also suitable as a text for advanced courses on the subject.