Abstract: A method for synchronizing clocks in a packet transport network. The method comprises, receiving an external network clock at a central packet network node and transmitting timing information to a plurality of packet network devices, the timing information based upon the external network clock. The method further comprises, transmitting and receiving data that is synchronized to the timing information to a plurality of connected packet network devices. And finally, delivery of packets to an external interface via a packet network that contains data synchronized to the external network clock.

Abstract: A method for communicating information is disclosed wherein a time slot is allocated in a time division multiple access system for a transmission from a subscriber to a headend. Synchronization of a clock of the subscriber with respect to a clock of the headend is enhanced using a message transmitted from the headend to the subscriber which is indicative of an error in a subscriber transmission time with respect to the time slot. A feedback loop process is used to determine at least one of fractional symbol timing correction and carrier phase correction of a transmission from the subscriber to the headend. Filter coefficients are generated at the headend from a ranging signal transmitted from the subscriber to the headend and transmitting the filter coefficients from the headend to the subscriber, the filter coefficients being used by the subscriber to compensate for noise in a transmission from the subscriber to the headend.

Abstract: A number of features for enhancing the performance of a cable transmission system in which data is transmitted between a cable modem termination system at a headend and a plurality of cable modems located different distances from the headend. The power transmission level, slot timing, and equalization of the cable modems are set by a ranging process. Data is transmitted by the modems in fragmented form. Various measures are taken to make transmission from the cable modems robust. The upstream data transmission is controlled to permit multiple access from the cable modems.

Abstract: A number of features for enhancing the performance of a cable transmission system in which data is transmitted between a cable modem termination system at a headend and a plurality of cable modems located different distances from the headend. The power transmission level, slot timing, and equalization of the cable modems are set by a ranging process. Data is transmitted by the modems in fragmented form. Various measures are taken to make transmission from the cable modems robust. The upstream data transmission is controlled to permit multiple access from the cable modems.

Abstract: A number of features for enhancing the performance of a cable transmission system in which data is transmitted between a cable modem termination system at a headend and a plurality of cable modems located different distances from the headend. The power transmission level, slot timing, and equalization of the cable modems are set by a ranging process. Data is transmitted by the modems in fragmented form. Various measures are taken to make transmission from the cable modems robust. The upstream data transmission is controlled to permit multiple access from the cable modems.

Abstract: A plurality of CMTS devices are linked together and synchronized to facilitate communication between the respective CMTS devices and respective downstream cable modems. According to one embodiment of the invention, one of the CMTS devices is designated as a master device, and the other CMTS devices are designated as slave devices. The respective CMTS devices are connected to each other by means of a synchronization bus. The master CMTS device then generates and broadcasts a future time stamp value, which is received by the respective slave CMTS devices. When the time stamp counter in the master CMTS device reaches the transmitted value, a control signal is broadcast over the synchronization bus. The slave CMTS devices then retrieve the time stamp value and reset their respective local time stamp counters to the received value. In this manner, the CMTS devices are synchronized.

Abstract: A method and system for allocating an initial maintenance request (IMR) for an upstream channel in a communications system, wherein the communication system includes a headend and at least one remote device associated with the channel. A first propagation delay from the headend to the remote device having the greatest delay is determined. Likewise, a second propagation delay from the headend to the remote device experiencing the least delay is determined. The IMR is then defined to be shorter than the first propagation delay and at least as long as the difference between the two propagation delays. The starting point of the IMR is established by modifying the clock output of the headend. A modification value is added to the headend clock output. The modification value corresponds to a time interval that can be as long as the propagation delay from the headend to the remote having the shortest delay.

Abstract: A number of features for enhancing the performance of a cable transmission system in which data is transmitted between a cable modem termination system at a headend and a plurality of cable modems located different distances from the headend. The power transmission level, slot timing, and equalization of the cable modems are set by a ranging process. Data is transmitted by the modems in fragmented form. Various measures are taken to make transmission from the cable modems robust. The upstream data transmission is controlled to permit multiple access from the cable modems.

Abstract: A number of features for enhancing the performance of a cable transmission system in which data is transmitted between a cable modem termination system at a headend and a plurality of cable modems located different distances from the headend. The power transmission level, slot timing, and equalization of the cable modems are set by a ranging process. Data is transmitted by the modems in fragmented form. Various measures are taken to make transmission from the cable modems robust. The upstream data transmission is controlled to permit multiple access from the cable modems.

Abstract: Upstream requests such a bandwidth requests, are processed by CMTS out of order on a priority basis to reduce latency in responding to the request. Specifically, a cable modem termination system (CMTS) is connected to a plurality of cable modems by a cable plant. The CMTS has a burst receiver adapted to be connected to the cable plant to process upstream data packet units and bandwidth requests transmitted by the cable modems. Each packet includes a header that uniquely distinguishes the bandwidth requests from other data types. Packet data units are arranged in a first memory queue. Bandwidth requests are arranged in a second memory queue. The headers of the packets processed by the burst receiver are inspected as they arrive at the CMTS to determine if the packets are packet data units or bandwidth requests. Packet data units are routed to the first memory queue. Bandwidth requests are routed to the second memory queue.

Abstract: A method for synchronizing clocks in a packet transport network. The method comprises, receiving an external network clock at a central packet network node and transmitting timing information to a plurality of packet network devices, the timing information based upon the external network clock. The method further comprises, transmitting and receiving data that is synchronized to the timing information to a plurality of connected packet network devices. And finally, delivery of packets to an external interface via a packet network that contains data synchronized to the external network clock.

Abstract: A plurality of CMTS devices are linked together and synchronized to facilitate communication between the respective CMTS devices and respective downstream cable modems. According to one embodiment of the invention, one of the CMTS devices is designated as a master device, and the other CMTS devices are designated as slave devices. The respective CMTS devices are connected to each other by means of a synchronization bus. The master CMTS device then generates and broadcasts a future time stamp value, which is received by the respective slave CMTS devices. When the time stamp counter in the master CMTS device reaches the transmitted value, a control signal is broadcast over the synchronization bus. The slave CMTS devices then retrieve the time stamp value and reset their respective local time stamp counters to the received value. In this manner, the CMTS devices are synchronized.

Abstract: A method for communicating information is disclosed wherein a time slot is allocated in a time division multiple access system for a transmission from a subscriber to a headend. Synchronization of a clock of the subscriber with respect to a clock of the headend is enhanced using a message transmitted from the headend to the subscriber which is indicative of an error in a subscriber transmission time with respect to the time slot. A feedback loop process is used to determine at least one of fractional symbol timing correction and carrier phase correction of a transmission from the subscriber to the headend. Filter coefficients are generated at the headend from a ranging signal transmitted from the subscriber to the headend and transmitting the filter coefficients from the headend to the subscriber, the filter coefficients being used by the subscriber to compensate for noise in a transmission from the subscriber to the headend.

Abstract: A method for communicating information is disclosed wherein a time slot is allocated in a time division multiple access system for a transmission from a subscriber to a headend. Synchronization of a clock of the subscriber with respect to a clock of the headend is enhanced using a message transmitted from the headend to the subscriber which is indicative of an error in a subscriber transmission time with respect to the time slot. A feedback loop process is used to determine at least one of fractional symbol timing correction and carrier phase correction of a transmission from the subscriber to the headend. Filter coefficients are generated at the headend from a ranging signal transmitted from the subscriber to the headend and transmitting the filter coefficients from the headend to the subscriber, the filter coefficients being used by the subscriber to compensate for noise in a transmission from the subscriber to the headend.

Abstract: A plurality of CMTS devices are linked together and synchronized to facilitate communication between the respective CMTS devices and respective downstream cable modems. According to one embodiment of the invention, one of the CMTS devices is designated as a master device, and the other CMTS devices are designated as slave devices. The respective CMTS devices are connected to each other by means of a synchronization bus. The master CMTS device then generates and broadcasts a future time stamp value, which is received by the respective slave CMTS devices. When the time stamp counter in the master CMTS device reaches the transmitted value, a control signal is broadcast over the synchronization bus. The slave CMTS devices then retrieve the time stamp value and reset their respective local time stamp counters to the received value. In this manner, the CMTS devices are synchronized.

Abstract: A number of features for enhancing the performance of a cable transmission system in which data is transmitted between a cable modem termination system at a headend and a plurality of cable modems located different distances from the headend. The power transmission level, slot timing, and equalization of the cable modems are set by a ranging process. Data is transmitted by the modems in fragmented form. Various measures are taken to make transmission from the cable modems robust. The upstream data transmission is controlled to permit multiple access from the cable modems.

Abstract: A method and system for allocating an initial maintenance request (IMR) for an upstream channel in a communications system, wherein the communication system includes a headend and at least one remote device associated with the channel. A first propagation delay from the headend to the remote device having the greatest delay is determined. Likewise, a second propagation delay from the headend to the remote device experiencing the least delay is determined. The IMR is then defined to be shorter than the first propagation delay and at least as long as the difference between the two propagation delays. The starting point of the IMR is established by modifying the clock output of the headend. A modification value is added to the headend clock output. The modification value corresponds to a time interval that can be as long as the propagation delay from the headend to the remote having the shortest delay.

Abstract: A number of features for enhancing the performance of a cable transmission system in which data is transmitted between a cable modem termination system at a headend and a plurality of cable modems located different distances from the headend. The power transmission level, slot timing, and equalization of the cable modems are set by a ranging process. Data is transmitted by the modems in fragmented form. Various measures are taken to make transmission from the cable modems robust. The upstream data transmission is controlled to permit multiple access from the cable modems.