OSI explained

Open Systems Interconnection, usually called OSI, became a central force in computer networking during the 1990s. Its aim is to let machines exchange information whatever their physical location, operating system, network layout or maker. Its reach extends across business, commerce, schooling and home use, covering everyday tasks such as sending mail to someone abroad, ordering equipment or withdrawing cash from a machine.

This book is written for readers who already understand computers and want to see how OSI works in practice. Rather than serving as a lookup guide, it explains the system and sets out its rules as defined in standards published by the International Standards Organization (ISO). These standards describe what computer systems must do to run OSI applications, including X400 electronic mail and FTAM file transfer. Because the standards rest on the ISO Layer Reference Model, the author gives a full tutorial on that model first, so the reader can grasp the common approach behind the whole framework.

The upper four layers of the model get particular attention, since they govern how systems work together to run complex applications over basic data networks. Separate chapters cover FTAM, X400 (MOTIS) and directory services, and a closing chapter walks through worked examples of OSI operation step by step, using diagrams.