Internet vs. Internetwork — What's the Difference?

The Internet, capitalized, refers specifically to the worldwide collection of networks that use the Internet Protocol Suite (TCP/IP) to serve billions of users globally. It is a network of networks that consists of private, public, academic, business, and government networks, all linked by a broad array of electronic, wireless, and optical networking technologies. In contrast, an internetwork (or "internet" with a lowercase "i") describes any connection of multiple computer networks or devices that are linked together to form a single network. The term internetwork emphasizes the process or architecture behind connecting different networks, without implying the scale or the specific protocols used.

The Internet is characterized by its use of standardized communication protocols, such as TCP/IP, which ensure that diverse networks can communicate efficiently. Whereas, an internetwork might use different protocols, but when referring to IP-based networks, it aligns with the principles of the Internet's architecture. The primary distinction here is between the specific, singular entity known as the Internet and the general concept of network interconnectivity that internetwork represents.

Services and applications like the World Wide Web, email, voice over Internet Protocol (VoIP), and file sharing operate on the Internet, leveraging its global reach and standardized protocols to connect users and information worldwide. On the other hand, the concept of internetworking allows for the creation of any networked connections between more localized or specific groups of networks, not necessarily intended for global or public access.

The development of the Internet was a result of research and development projects in the late 20th century that aimed to build robust, fault-tolerant, and global communication via computers. Internetworking, as a concept, has been integral to this development, representing the technical foundation upon which the Internet was built. It involves the technical practices and protocols that allow for the interconnection of separate and distinct networks into a larger, functional network.

While the Internet has become synonymous with global communication, digital commerce, and the exchange of vast amounts of data, an internetwork might serve a more localized or specialized purpose. For example, a corporate internetwork (often called an intranet) connects various parts of an organization’s IT infrastructure to enable communication and data sharing within the company.