DECnet

DECnet is a suite of created by Digital Equipment Corporation, originally released in 1975 in order to connect two PDP-11 minicomputers. It evolved into one of the first peer-to-peer network architectures, thus transforming DEC into a networking powerhouse in the 1980s. Initially built with three layers, it later (1982) evolved into a seven-layer OSI-compliant networking protocol.

DECnet was built right into the DEC flagship operating system VMS since its inception. Later Digital ported it to Ultrix, as well as Apple Macintosh and IBM PC running variants of DOS and Microsoft Windows under the name DEC Pathworks, allowing these systems to connect to DECnet networks of VAX machines as terminal nodes. More recently, an open-source version has been developed for Linux. DECnet code in the Linux kernel was marked as orphaned on February 18, 2010.

DECnet refers to a specific set of hardware and software networking products which implement the DIGITAL Network Architecture (DNA). The DIGITAL Network Architecture has a set of documents which define the network architecture in general, state the specifications for each layer of the architecture, and describe the which operate within each layer. Although network protocol analyzer tools tend to categorize all protocols from DIGITAL as "DECnet", strictly speaking, non-routed DIGITAL protocols such as LAT, SCS, AMDS, LAST/LAD are not DECnet protocols and are not part of the DIGITAL Network Architecture.

To trace the evolution of DECnet is to trace the development of DNA. The beginnings of DNA were in the early 1970s. DIGITAL published its first DNA specification at about the same time that IBM announced its Systems Network Architecture (SNA). Since that time, development of DNA has evolved through the following phases:

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