Abstract: Systems and methods are presented to prevent denial of service attacks through the use of an interleaved pseudo-random sequence that is generated from two or more pseudo-random codes. Portions of the pseudo-random codes are interleaved with each other using a pre-determined instruction pattern. A message incorporating the interleaved sequence is transmitted to a receiver, which identifies the interleaved bit sequence in the message and, if the interleaved bit sequence is identified in the message, allows access to the service.

Abstract: Systems and methods are presented to prevent denial of service attacks through the use of an interleaved pseudo-random sequence that is generated from two or more pseudo-random codes. Portions of the pseudo-random codes are interleaved with each other using a pre-determined instruction pattern. A message incorporating the interleaved sequence is transmitted to a receiver, which identifies the interleaved bit sequence in the message and, if the interleaved bit sequence is identified in the message, allows access to the service.

Abstract: A switch router and one or more gateways incorporating a diagnostic and calibration system that performs RF characterization of an underlying cable plant. The switch router is connected at a point of insertion or point of distribution and each gateway is located downstream, such as at corresponding subscriber locations. The switch router and each gateway sends a test signal with known characteristics and power level, and the receiving device determines noise level and power loss for the corresponding downstream and upstream channel pair. The power loss information is used to calibrate the power level of the transmitters. The noise levels are used to determine if the selected modulation schemes employed for normal communications is realizable. A frequency analysis, such as FFT or the like, is performed on the upstream test signal spectrum to derive valuable frequency information for the upstream channel or the entire upstream bandwidth.

Abstract: A switch router and one or more gateways incorporating a diagnostic and calibration system that performs RF characterization of an underlying cable plant. The switch router is connected at a point of insertion or point of distribution and each gateway is located downstream, such as at corresponding subscriber locations. The switch router and each gateway sends a test signal with known characteristics and power level, and the receiving device determines noise level and power loss for the corresponding downstream and upstream channel pair. The power loss information is used to calibrate the power level of the transmitters. The noise levels are used to determine if the selected modulation schemes employed for normal communications is realizable. A frequency analysis, such as FFT or the like, is performed on the upstream test signal spectrum to derive valuable frequency information for the upstream channel or the entire upstream bandwidth.