Internetwork

An internetwork is a network of networks connected by routers and gateways that enables data exchange across organizational or geographic boundaries. Internetworking relies on standardized addressing and routing so that a host on one network can communicate with a host on another network, even if their underlying technologies differ.

Historically, internetworking emerged from early military and academic networks in the 1960s and 1970s, culminating in the adoption of Transmission Control Protocol/Internet Protocol (TCP/IP) as the universal protocol suite in the 1980s. The term internetwork is sometimes used to describe the Internet itself as a global network of networks.

The architecture of an internetwork includes routers and gateways that forward packets between networks, edge devices that connect end hosts, and various link-layer technologies such as Ethernet, Wi-Fi, and fiber. Core protocols include IP addressing, TCP or UDP transport, and routing protocols like BGP, OSPF, and RIP. Interconnection points and Internet exchange points (IXPs) help optimize traffic flow.

Internetworking enables widely used services such as the World Wide Web, email, file transfer, and voice over IP. It supports multiple administrative domains and policy constraints, with security and management considerations addressing authentication, encryption, access control, and privacy.

Management and governance of internetworking involve standardization bodies, network operators, and public and private institutions. Ongoing topics include IPv4 address exhaustion, IPv6 adoption, routing security, and interoperable publishing of data and services across diverse networks.