Backbone Provider
Backbone provider is an organization that supplies access to high-end transmission lines that connects users to internet. It is different from ISP's in the sense that whereas ISP's provide the customers with access to the internet, Backbone providers supplies the ISP with access to the lines like T1 or T3 lines. These lines connect ISP's to each other. Major Backbone providers are MCI, Sprint, UUNET, AGI and BBN.