Abstract: A method and system for compressing and transmitting data using asynchronous transfer mode (ATM) is disclosed. The data include a plurality of segments. Each of the plurality of segments has a first end and a second end. In one aspect, the method and system include representing the first end of a segment with a partition compression code word and compressing a remaining portion of the segment. The method and system could also combine the marking of the boundary and subsequent data into a compound compression code word. In another aspect, the method and system include representing the first end of a segment with a transparent mode command, transmitting the transparent mode command, and transmitting a remaining portion of the segment.

Abstract: A method, and a system for performing the method, for computing cyclic redundancy code (CRC) for use in a communication data stream M bits at a time for an input sequence u(n) whose length is not a multiple of M. The method includes (i) representing a frame of data to be protected as the input sequence; (ii) determining a cyclic redundancy code (CRC) for the input sequence M bits at a time from a state vector, until a last block of the input sequence is reached; (iii) if the last block of the input sequence is full, then determining the CRC to be a completed CRC; and (iv) if the last block of the input sequence is not full, then performing three functions. The method can further include (v) appending the completed CRC as a frame check sequence (FCS) to the communication data stream for detection by a receiving device.

Abstract: A method, and a system for employing the method, for computing a cyclic redundancy code (CRC) of a communication data stream taking a number of bits M at a time to achieve a throughput equaling M times that of a bit-at-a-time CRC computation operating at a same circuit clock speed. The method includes (i) representing a frame of the data stream to be protected as a polynomial input sequence; (ii) determining one or more matrices and vectors relating the polynomial input sequence to a state vector; and (iii) applying a a linear transform matrix for the polynomial input sequence to obtain a transformed version of the state vector. The method can further include (iv) applying a linear transform matrix to the transformed version of the state vector to determine a CRC for the polynomial input sequence, if the communication data stream is received by a network device.

Abstract: A codec detects congestion in a packet network and responds via a session control protocol to re-negotiate codec-type and/or parameters with the receiving codec to reduce bit rate for supporting a session. Once the connection and session are established, encoded packets start flowing between the two codecs. A control entity sends and receives network congestion control packets periodically in the session. The congestion control packets provide a “heartbeat” signal to the receiving codec. When the network is not congested, all “heartbeat” packets will be passed through the network As network congestion increases, routers within the network discard excess packets to prevent network failure. The codecs respond to the missing packets by slowing down the bit rate or proceeding to renegotiate a lower bit rate via the session control protocol. If there are no missing packets, the codecs detect if the session is operating at the highest bit rate, and if not, re-negotiate a higher bit rate.

Abstract: Packetized voice, video, and data traffic (data frames) are received in a communication traffic sorter. The data frames have a dispatch priority corresponding to their transmission characteristics (flow) and a quality of service parameters. The communication traffic sorter analyzes information in data packets within each data frame and determines an optimum flow for the data frames. A data frame is assigned to a selected queue based on an analysis of the information in its data packets. A data frame may also be assigned to a queue based on a prior analysis of a data frame with like transmission characteristics. Results of analysis are stored and indexed to facilitate processing of subsequent data frames. The network access sorter has circuits to un-pack and re-pack the data frame, when called for, to allow user transmitted data to be processed to create a modified data frame.

Abstract: A remote controller is coupled to a target system via a computer network A real time probe is installed in software executing on a target system, typically a Digital Signal Processor (DSP). The remote controller includes a “debugger user interface” which accepts and interprets scoping commands issued by a developer. A controller network driver constructs appropriate network packets to be sent over the network to the target system. The target system has a control processor which runs a target network driver for receiving the network packets containing the scoping commands. The scoping commands are sent to an “embedded debugger” which performs the requested probing/scoping. When the DSP code runs across an address where the probe is installed, the embedded debugger will collect the signal values. The collected scope data will be interleaved and sent to the target network driver which, will encapsulate the information into suitable packets to send back to the controller via the network.

Abstract: A packet network congestion control system using a biased packet discard policy includes a plurality of end points having codecs operating in a framework, e.g. ITU-T H.323 protocol to establish a communication session. The protocol enables the codecs to negotiate codec type and associated parameters. Once a connection and session are established, compressed voice and data packets start flowing between the two end points. A control entity supplies congestion control packets periodically. The control packets provide a “heartbeat” signal to the codec at the other end of the session. Each codec receiver uses the “heartbeat” signal as an indication of network congestion. As network congestion increases, routers within the network discard excess packets to prevent network failure. The network discards all packets classified as congestion control packets whenever a flow control mechanism detects congestion or a trend toward congestion.

Abstract: A shared digital subscriber line modem achieves reduced total power consumption and data security by generating and transmitting a physical data frame which includes a control channel and a data field to only the connected client modem associated with the intended recipient. A second physical frame which does not include the data field is generated and transmitted to all of the other connected client modems. This method results in a reduction in the power required and provides improved data security by preventing data access to non-addressed client modems.

Abstract: A low power DSL modem transmitter, suitable for incorporation in integrated DSLAM server line cards, transmits full power physical frames which include a control channel and a data field when data is available for transmission and physical frames having only a control channel or a control channel and a low power synchronization field when data is not available for transmission. And a method for controlling the total power dissipated in the integrated DSLAM by selectively restricting the flow of data packets to the DSLs.

Abstract: Modems, methods, and computer program products for falling back to a low speed mode of operation upon detection of abnormal line conditions during startup perform a first phase of a multiphase startup procedure in accordance with a high speed mode of operation. A determination is then made whether the line conditions will support high speed communication. If a high speed connection cannot be established, then subsequent phases of the startup procedure will be performed in accordance with the low speed mode of operation. Otherwise, subsequent phases of the startup procedure will be performed in accordance with the high speed mode of operation.

Abstract: Decision feedback equalizers having a stabilization capability, and methods and computer program products for stabilizing a decision feedback equalizer under severe error conditions use output samples from an equalizer to determine whether a severe error event has occurred in accordance with predefined criteria. If a severe error occurs, then a determination is made to evaluate whether the number of severe errors that have occurred has exceeded a threshold. If the threshold has been exceeded, then the coefficients for the filter(s) in the decision feedback equalizer are preserved in their current state. Severe errors can cause the equalizer filter coefficients to be pulled away from their normal operating values, which can result in several modulation cycles passing before the coefficients are restored.

Abstract: A network interface circuit includes an off-hook/on-hook circuit, responsive to the communications network, that provides an off-hook voltage substantially equal to the communications network voltage in an off-hook state and that provides an on-hook voltage in an on-hook state. A voltage controlled current source provides a load current which is proportional to a communications network voltage provided by the communications network. A divider circuit, responsive to the off-hook/on-hook circuit, provides an input voltage and produces an over-voltage, wherein the input voltage is proportional to off-hook or on-hook voltage. A clamping circuit limits the input voltage to one of a first or second predetermined value based on the operating mode and generates a current limited voltage.

Abstract: A communication interface and a design method therefor simultaneously shape a synthesized terminating impedance matching different frequency bands on different connecting communication circuits and a receive path response to prevent frequency roll-off. In some cases, for example based on specified network requirements in a particular country, the terminating impedance presented by the interface must have different frequency characteristics for received signals in different bands of frequencies. A transconductance amplifier and feedback loop provide the terminating impedance for signals received from the communication circuit and serve as a source impedance for signals transmitted by the interface to the telephone line. Signals with different frequencies will generally be received from the telephone line. These different characteristics are realized using different filter networks in the feedback loop.

Abstract: A communication interface and a design method therefor provide a synthesized terminating impedance matching different frequency bands on a communication circuit. In some cases, for example based on specified network requirements in a particular country, the terminating impedance presented by the interface must have different frequency characteristics for received signals in different bands of frequencies. A transconductance amplifier and feedback loop provide the terminating impedance for signals received from the communication circuit and serves as a source impedance for signals transmitted by the interface to the telephone line. Signals with different frequencies will generally be received from the telephone line. These different characteristics are realized using different filter networks in the feedback loop. Each network provides a matching terminating impedance to the communication circuit according to the frequency band applied to the circuit.

Abstract: A method and system in a data processing system are disclosed for the retransmission of only a portion of a data packet which had originally been transmitted incorrectly. A first data link is established between a first computer system and a second computer system. In response to the establishment of the first data link, a second data link is established between the first and second computer systems, whereby the first and second data links are related. A plurality of data packets are transmitted from the first computer system to the second computer system utilizing the first data link. Each of the data packets includes a plurality of segments. A determination is made whether each of the plurality of data packets is received correctly. In response to a determination that one of the plurality of data packets is received incorrectly, a portion of the data packet which was transmitted incorrectly is determined.

Abstract: A method and system in a data communications system are disclosed for the establishment of multiple, related data links and the utilization of one of the data links for error correction of transmission errors occurring on the other data link. A first data link is established between a first computer system and a second computer system. In response to the establishment of the first data link, a second, related data link is established between the first and second computer systems. A plurality of data packets are transmitted from the first computer system to the second computer system utilizing the first data link. A determination is made whether each of the plurality of data packets is received correctly. In response to each determination that one of the plurality of data packets is not received correctly, the second computer system transmits a selective rejection packet for the one of the plurality of data packets to the first computer system utilizing the second data link.

Abstract: A time-division multiplexing synchronization mechanism employs a 1-bit/frame framing channel with a pattern that repeats every 2 frames. Acquisition and reacquisition of synchronization with such a framing pattern is enabled through the use of an explicit synchronization procedure. With this procedure, initial acquisition of frame synchronization as well as reframing after loss of synchronization are carried out while the transmission channel is carrying only a predefined bit pattern. When the receivers are in synchronization, synchronization is monitored and maintained using a 1-bit/frame framing channel, while the communications link is carrying multiplexed bit streams with the appropriate format.