A hierarchical cable modem clone detection system: A cable modem clone detection system uses a cable modem media access control (MAC) address and physical location information such as information relating to a cable interface, upstream and downstream port numbers, fiber node information, and load balancing group descriptors to determine if a cable modem is a clone. The hierarchical approach first make a clone determination at a cable modem termination system, then at a regional operations center and finally at a network operations center.