Definition of DECnet

DECnet is a suite of network protocols developed by Digital Equipment Corporation, primarily for use in their VAX and MicroVAX computer systems. It was first introduced in 1975, and provided a way for these systems to communicate with each other, allowing data transmission and resource sharing. DECnet has evolved through several stages, with DECnet Phase IV and DECnet Phase V being the most widely known and used versions.


D-E-C-net: “Dee-Ee-See-net”

Key Takeaways

  1. DECnet is a suite of network protocols created by Digital Equipment Corporation, designed for their range of minicomputers and mainframes, allowing them to communicate and share resources over local and wide area networks.
  2. Introduced in the 1970s, DECnet evolved through multiple phases (from DECnet Phase I to DECnet Phase V), enhancing its capabilities, improving performance, and expanding its support for various hardware, software, and communication platforms.
  3. Although DECnet’s popularity has significantly decreased with the rise of TCP/IP as the dominant networking infrastructure, it still retains a niche user base in some industries and legacy systems, where its stability, reliability, and security features are valued.

Importance of DECnet

DECnet, an abbreviation for Digital Equipment Corporation Network, is an important term in technology as it refers to a suite of communication protocols created by Digital Equipment Corporation.

Pioneered in the 1970s, DECnet played a crucial role in the early development of computer networking systems and enabled communication between different DEC computers in a streamlined and secure manner.

With several phases of evolution, it progressively adapted to the changing technology landscape and served as inspiration for the development of other networking protocols, such as TCP/IP.

DECnet’s historical impact on computer communication establishes it as a landmark innovation in the field of networking technology.


DECnet is a suite of network protocols designed to facilitate communication and resource sharing among computers within a distributed computing environment. Developed by Digital Equipment Corporation (DEC) in the 1970s, its primary purpose was to enable computers and devices within a network to easily share information and exchange data with one another.

This approach allowed a higher level of collaboration, as users from various systems had the ability to access resources, such as files, applications and databases, which were stored on different machines within the network. The main advantage of DECnet lies in its flexibility, as it supports a wide range of network sizes and topologies, making it applicable in diverse computing environments including local area networks (LANs) and wide area networks (WANs).Throughout its evolution, DECnet has gone through multiple phases, each introducing new features to accommodate the growing demand for seamless network communication and increased scalability.

For instance, DECnet Phase II and Phase III saw the implementation of hierarchical routing and improved network manageability, while Phase IV adopted connection-oriented transport services. During the 1990s, with the rise of TCP/IP as the industry standard for data communication, DECnet transitioned to phase V, incorporating an OSI-compatible protocol stack.

Overall, DECnet revolutionized the way networked systems communicate and laid the groundwork for contemporary network technologies. Though not as popular today as it was in its early years, DECnet remains an essential part of some legacy systems within various industries.

Examples of DECnet

DECnet, short for Digital Equipment Corporation Network, is a suite of network protocols primarily used in Digital Equipment Corporation’s computers. It was developed in the late 1970s, and over time, it has evolved through different versions. Here are three real-world examples of systems that employed DECnet technology:

NASA: In the late 1980s through the mid-1990s, NASA used the DECnet protocol suite on its networks for communication, data exchange, and command and control of various systems. The Hubble Space Telescope and its ground-based communication infrastructure utilized DECnet Phase IV for data analysis and management, supporting data sharing and inter-system communication among different computer platforms.

CERN: During the 1980s and 1990s, the European Organization for Nuclear Research (CERN) used DECnet technologies for resource sharing and communication among its various research facilities. DECnet played a vital role in enabling scientists at CERN to access resources in real-time, including scientific databases, collaboratively.

DEC VAXcluster Systems: The Digital Equipment Corporation VAXcluster system, which was widely used in various industries during the 1980s and 1990s, incorporated the DECnet control program to support communication and resource sharing among different computing nodes in the cluster. This VAXcluster System was employed in industries such as manufacturing, finance, and telecom for data processing, scientific calculations, and administrative tasks.


What is DECnet?

DECnet is a suite of network protocols created by Digital Equipment Corporation (DEC) to allow their computers and systems to communicate with each other. It was initially developed in the 1970s and was widely used for data communication and exchange in DEC-based computer systems.

What were the main components of DECnet?

DECnet consisted of several components, including the Network Control Program (NCP), Data Access Protocol (DAP), and the Session Control Protocol (SCP). These components enabled communication between network devices, file transfers, and session management, respectively.

What were some of the features of DECnet?

DECnet was known for its easy-to-use interface, ability to support a wide range of systems, and its robustness and reliability. Some key features of DECnet included support for hierarchical routing, automatic reconfiguration, and built-in security mechanisms.

How has DECnet evolved over the years?

DECnet has gone through several versions, starting with DECnet Phase I and progressing through to DECnet-Plus (also known as DECnet Phase V). Each version incorporated new features, improved performance, and extended support for a wider range of systems and applications. Although DECnet is not widely used today, it still has a loyal user base for certain legacy applications and systems.

Is DECnet still in use today?

DECnet is not as widely used as it once was, but some organizations still maintain legacy DECnet applications and systems. The rise of other network protocols, such as TCP/IP, led to a decline in DECnet’s popularity. However, knowledge of DECnet may still be useful for working with legacy equipment and applications.

Related Technology Terms

  • DECnet Phase V Protocol
  • DECnet Routing
  • Digital Network Architecture (DNA)
  • Network Control Program (NCP)
  • DECnet Network Management

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