Technologies for Network Architecture and Implementation
by F. D. Smith, C. H. West
Systems Network Architecture (SNA) provides a framework for constructing networks of distributed processors and terminals. This paper discusses some of the fundamental properties of network architectures such as SNA, and the evolution of formal descriptive methods that provide precise, complete definitions of the architecture. This has culminated in the development of a programming language, Format and Protocol Language (FAPL), tailored for programming a reference model or meta-implementation of an SNA node. In this form, the architecture specification is itself machine-executable. This property has led to new software technologies that improve quality and productivity in the processes for developing a network architecture and the product implementations derived from it. Automated protocol validation provides the tool necessary to ensure a correct and internally consistent definition of the architecture. This definition can then be used as a standard for testing products to determine compliance with the architecture. Direct implementation of network software by compiling the meta-implementation program is another emerging technology. This paper reviews the current state of work in these areas.