What is a backbone provider?
A backbone provider is an organization or business unit that provides access to high-speed data transmission lines and other related infrastructure to other organizations that need them. This can be viewed as a superset of ISPs (Internet Service Providers). When an ISP provides Internet connectivity for end users, a backbone provider provides the ISP with a high-speed connection to the Internet itself.
A backbone provider is the basic foundation of the Internet, providing connections between ISPs and between international borders. The Internet backbone is defined as the main data route between large computer networks and core routers on the Internet. These routes are often run by governments, large commercial organizations, or academic organizations. Any organization that has control over large, high-speed networks and the (usually) fiber optic links that connect them, and then allows others to use the network, is considered a backbone provider.
Backbone providers are typically those who have huge arrays and networks of cables laid out that connect large areas, like large telecommunications companies like AT&T, Verizon, and Sprint. These telecom giants sell their services to small ISPs and, unsurprisingly, are ISPs themselves.
The largest backbone providers are known as tier 1 providers, and these organizations have huge networks that connect territories and countries around the world and are not limited to their country of origin.