one of the private companies maintaining and servicing the Internets high-speed backbones. Included among the companies are MCI, Sprint, UUNET/MIS, PSINet. and BBN Planet.
Companies that provide services such as ADSL, HDSL, ATM, Frame Relay, Internet Access, or other services. Usually use their own switching equipment, or they lease the equipment - and they normally utilize a local telco or CAP for the local loop. They link nodes via high capacity circuits. They also may have interconnection agreements with other telecom companies.