X.25 Explained: Protocols for Packet Switching Networks (Computers & Their Applications Series)

An interesting story in the development of networking. The idea of a heterogeneous network was a breakthrough. In addition to describing the lower 4 levels of the ISO (International Standards Organization) model for Open Systems Interconnection (OSI) the preface reminds us what the situation was then. Every device or application was a unique problem. Digital Equipment Corporation and IBM dominated the market with two "standards", DECnet and SNA, respectively. Other manufacturers implemented one or the other. In 1977 ISO started a project to develop protocols the cover a range of requirements regarding error control, file access, job transfer, terminal control, and other functions.the book recalls an attempt by UK Telecom and IBM to set up a Value Added Network based on SNA, but the government refused them a license because they did not comply with OSI. It was an historic moment.