Computer networking

Computer networking is built on a layered architecture that separates functions into manageable levels. The Open Systems Interconnection (OSI) model defines seven layers, from the physical medium to application services, while the TCP/IP model, which underpins the Internet, condenses this into four layers. Each layer provides services to the layer above and consumes services from the layer below, enabling modular design and interoperability.¹ Key components include network interfaces, switches, routers, and protocols such as Ethernet, IP, and TCP. Addressing schemes, like IP addresses and MAC addresses, identify devices uniquely, and routing algorithms determine optimal paths for data packets. Network topologies—such as star, mesh, and bus—define how devices are connected, affecting performance and fault tolerance.²

The origins of computer networking trace to the 1960s, with the development of packet switching by Paul Baran and Donald Davies, and the ARPANET, funded by the U.S. Department of Defense, which sent its first message in 1969. The 1970s saw the creation of Ethernet by Robert Metcalfe and the development of the TCP/IP protocol suite by Vint Cerf and Bob Kahn, which became the standard for internetworking. The 1980s brought the proliferation of LANs and the emergence of the Internet as a global network, while the 1990s witnessed the World Wide Web, which made networking accessible to the public. Since then, advances in wireless technologies, fiber optics, and network virtualization have transformed networking into a ubiquitous utility.

Networks are classified by scale and purpose: personal area networks (PANs), local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). LANs typically use Ethernet or Wi-Fi, while WANs rely on leased lines, MPLS, or satellite links. Wireless networking, based on IEEE 802.11 standards, has become dominant for end-user access. Software-defined networking (SDN) and network function virtualization (NFV) decouple control from data planes, enabling dynamic, programmable infrastructures. Data centers employ high-speed fabrics, such as InfiniBand and 100GbE, to support cloud services. Emerging technologies include 5G, which promises ultra-low latency, and quantum networking, which leverages quantum entanglement for secure communication.

Beyond mainstream applications, computer networking has niche dimensions. For instance, delay-tolerant networking (DTN) is designed for interplanetary communication, where signal delays can be minutes or hours, as used by NASA's Deep Space Network. Underwater acoustic networks enable oceanographic monitoring, but face challenges like low bandwidth and high latency. Power-line communication (PLC) uses existing electrical wiring for data transmission, a technique employed in smart grids. Also, the concept of network neutrality has sparked regulatory debates, affecting how data is prioritized. Historically, the first network email was sent over ARPANET in 1971, and the first network packet was sent over a telephone line in 1965. These examples illustrate the breadth of networking beyond typical office or home use.

Packet switching

A method of data transmission where messages are broken into packets, each routed independently across the network.

TCP/IP

The Transmission Control Protocol/Internet Protocol suite, the foundational protocols of the Internet.

OSI model

A conceptual framework that standardizes network functions into seven layers.

LAN

A local area network, a network confined to a small geographic area like an office or home.

Router

A device that forwards data packets between networks, directing traffic based on IP addresses.