Abstract: A supervisory communications device, such as a headend device within a communications network, monitors and controls communications with a plurality of remote communications devices throughout a widely distributed network. The supervisory device allocates bandwidth on the upstream channels by sending MAP messages over its downstream channel. A highly integrated media access controller integrated circuit (MAC IC) operates within the headend to provide lower level processing on signals exchanged with the remote devices. The enhanced functionality of the MAC IC relieves the processing burden on the headend CPU and increases packet throughput. The enhanced functionality includes header suppression and expansion. DES encryption and decryption, fragment reassembly, concatenation, and DMA operations.

Abstract: A supervisory communications device, such as a headend device within a communications network, monitors and controls communications with a plurality of remote communications devices throughout a widely distributed network. The supervisory device allocates bandwidth on the upstream channels by sending MAP messages over its downstream channel. A highly integrated media access controller integrated circuit (MAC IC) operates within the headend to provide lower level processing on signals exchanged with the remote devices. The enhanced functionality of the MAC IC relieves the processing burden on the headend CPU and increases packet throughput.. The enhanced functionality includes header suppression and expansion. DES encryption and decryption, fragment reassembly, concatenation, and DMA operations.

Abstract: Requests are processed to transmit data packets upstream from a cable modem to a cable headend in a manner that minimizes the use of CPU operations and/or memory capacity. Data packets to be transmitted upstream are stored at the cable modem. The data packets each have a given transmission data byte length value. Burst profiles are received successively at the cable modem. Each time a new bust profile is received, a set of physical data length values corresponding to respective transmission data byte length values is calculated from the parameters of the received burst profile. The calculated set of physical data length values is stored in memory so the individual values can be retrieved from the transmission data byte length values again and again, rather than being re-calculated each time a conversion is made from transmission data byte length values to physical data length values. The same set of physical data length values is used until a new burst profile is received by the cable modem.

Abstract: A supervisory communications device, such as a headend device within a cable communications network, monitors and controls communications with a plurality of remote communications devices, such as cable modems, throughout a widely distributed network. The supervisory device allocates bandwidth on the upstream channels by sending MAP messages over its downstream channel. A highly integrated media access controller integrated circuit (MAC IC) operates within the headend to provide lower level DOCSIS processing on signals exchanged with the remote devices. The enhanced functionality of the MAC IC relieves the processing burden on the headend CPU and increases packet throughput. The enhanced functionality includes header suppression and expansion, DES encryption and decryption, fragment reassembly, concatenation, and DMA operations.

Abstract: Requests are processed to transmit data packets upstream from a cable modem to a cable headend in a manner that minimizes the use of CPU operations and/or memory capacity. Data packets to be transmitted upstream are stored at the cable modem. The data packets each have a given transmission data byte length value. Burst profiles are received successively at the cable modem. Each time a new bust profile is received, a set of physical data length values corresponding to respective transmission data byte length values is calculated from the parameters of the received burst profile. The calculated set of physical data length values is stored in memory so the individual values can be retrieved from the transmission data byte length values again and again, rather than being re-calculated each time a conversion is made from transmission data byte length values to physical data length values. The same set of physical data length values is used until a new burst profile is received by the cable modem.