What is the largest computer network in the world?

The Internet is the largest computer network. It is composed of thousands of smaller networks and connects billions of devices worldwide, handling the majority of data communication that occurs on a daily basis.

The largest private network as of 2014, is the NIPRNet, owned by the U.S. Department of Defense for distribution of communications. It has data services that allow customers access to a large, centralized, protected network, mainly used by military support roles. NIPRNet is considered an Internet backbone, a high-bandwidth-capacity line of data between large, centrally located servers. Several sets of Internet backbones exist across regions, providing redundant pathways for data. Backbones are owned by commercial, educational, governmental and private holdings, and are often built for handling traffic between facilities and the public Internet.