Abstract: Congestion management is provided using one or more receive queues organized into a queue list. Each queue is associated with a high water mark and a low water mark. The high water mark indicates a length at which the queue is considered congested. The low water mark is a length at which a congested queue is considered no longer congested. When a queue reaches or exceeds its high water mark, newly arriving frames destined for that queue which are eligible for discard are dropped. Frames arriving not marked as eligible for discard are enqueued at the queue's tail. Queues in the queue list are organized by relative priority. When a single queue above a predetermined priority is determined to be congested, all queues in the queue list are treated as congested. Congestion in lower priority queues results in only the individual congested queue being treated as congested.

Abstract: A system includes a communication device that includes a number of interface cards and a switching complex. Upon receiving a data signal, an input card modifies header bits of the data signal to identify an input port on which the data signal was received. The switching complex uses the modified header bits to communicate the data signal to an output card and associated output port. In a particular embodiment, the switching complex may also modify header bits to identify the input card.

Abstract: The method for handling call set-ups in a telecommunication network includes receiving a request to set up a call. The method also includes comparing a dynamic load value for a switch to a load threshold for the switch. The method further includes allowing the call to be set up when the dynamic load value is less than the load threshold.

Abstract: A congestion control mechanism in an ATM network access device includes segmentation and reassembly (SAR) logic that sends and receives Asynchronous Transfer Mode (ATM) cells to and from interface logic that transfers the cells to and from a switch fabric. The cells are transferred on ATM connections, including flow-controlled connections for which the sending of cells by the SAR logic is controlled in response to the settings of Generic Flow Control (GFC) bits appearing in the headers of ATM cells received by the SAR logic. The interface logic receives a congestion signal indicative of the level of congestion in a transmit buffer in the switch fabric. In response to the congestion signal, the interface logic sets the GFC bits in the headers of cells transferred to the SAR logic such that the cell transmission rate is maintained at a high average level while undesirable congestion in the transmit buffer is avoided. Hysteresis is employed in the setting of the GFC bits is response to the congestion signal.

Abstract: A network element management system which automatically configures itself, when an operator enters a component identifier, for optimal full-featured management of the identified component. This is preferably done by an autodiscovery process, and not by any mere lookup.

Abstract: A crosspoint switch uses an iterative process to deliver multicast packets from inputs to outputs. The switch includes output queues dedicated to the inputs, with backpressure indications provided from the output queues to the corresponding inputs. The inputs use the backpressure indications to schedule multicast packets for delivery to one or more of the output queues.

Abstract: In accordance with one embodiment of the present invention, a network element comprises a first subsystem operable to receive management transactions in a first management protocol and to map the transactions to a common management protocol. A second subsystem is operable to receive management transactions in a second management protocol and to map the transactions to the common management protocol. A common management information base (MIB) includes a dataset and a common interface to the dataset. The common interface is operable to access the dataset to process transactions received from the first and second subsystems in the common management protocol.

Abstract: A method and system for controlling the gain of the amplification of an optical signal is provided that includes both electrical feedforward and feedback. In a feedforward portion of an optical amplifier, the method includes receiving an optical signal and measuring an input power. Based on the measured input power and a desired gain, a feedforward pump power is determined. The pump power is adjusted based on the determined pump power. In a feedback portion of an optical amplifier, an output power is measured and gain is determined based on the output power and the measured input power. The measured gain is compared to a desired gain and the pump power is adjusted based on that comparison.

Abstract: A system for allocating bandwidth in a network element. The system determines whether a bandwidth allocation request is associated with a delay sensitive connection type. If so, the system selects a bandwidth allocation algorithm from a first set of bandwidth allocation algorithms. Otherwise, the system selects a bandwidth allocation algorithm from a second set of bandwidth allocation algorithms. The size of the bandwidth allocation request may be examined when selecting which bandwidth allocation algorithm to use. The system may round up the size of the bandwidth allocation request to a predetermined value. The selected bandwidth allocation algorithm may reserve slots in a bandwidth allocation table. Reserved slots that are equally spaced in the bandwidth allocation table avoid undue delays in servicing an associated connection. A binary tree representation of the table is described, wherein leaves of the binary tree correspond to individual table slots.

Abstract: A method for routing traffic in a network includes determining topology information for the network and determining traffic demands for multiple service classes. The method further includes determining an objective function for an optimization problem using the topology information and demands, and determining a solution to that specifies a network path for each demand.

Abstract: Telecommunication equipment includes a TDM interface operable to receive STS-n data, and a packet interface operable to receive packet/cell data and filling a STS-MC payload with the packet/cell data. An n×n cross-connect is coupled to the TDM interface and operable to switch and assign the STS-n data to any one of n STS-1 time slots. A multiplexer is coupled to the cross-connect and the packet interface and operable to combine the switched STS-n data and the STS-MC packet/cell data into an STS-N payload for transport, where N is the sum of n and M.

Abstract: A method perfomed by an ingress card includes receiving a packet with a destination identifier, and determining an aggregated link associated with the destination identifier that includes multiple egress ports. The method further includes determining a destination port from the egress ports of the aggregated link, and communicating the packet to the destination port.

Abstract: A system and method for maximum utilization of bandwidth of a resource incrementally adjusts in real time the allocated bandwidth per source queue per class of service based at least in part on the current status of a destination virtual output queue fill level. By varying the permissible bandwidth incrementally not only is the available bandwidth utilized optimally but also a desired class of service is maintained.

Abstract: A dispersion compensation system includes a dispersion compensation module and a dispersion enhancement module. The dispersion compensation module receives optical input and provides optical output having a negative dispersion relative to the optical input. The dispersion enhancement module receives optical signals from a transport fiber and may increase positive dispersion in the optical signals by a configured amount such that the positive dispersion provided by the transport fiber and the dispersion enhancement module substantially equals the magnitude of the negative dispersion provided by the dispersion compensation module.

Abstract: An optical modulator provides for preceding of a high data rate phase modulated optical signal. According to one embodiment, the modulator includes a first phase modulator and a second phase modulator. The first phase modulator modulates an optical carrier signal according to a first data signal to generate a modulated optical signal. The second phase modulator modulates the modulated optical signal according to a time delayed version of its optical output signal. According to another embodiment, the modulator electrically precodes multiple data streams and modulates the precoded data streams using a series of phase modulators to generate a precoded optical data signal.

Abstract: A communications device and method for effectively managing bandwidth within a telecommunications network carrying both time division multiplexed signals as well as data signals. The communications device having dialable TDM/cell and/or packet-based bandwidth management capability so that a network operator can select to manage bandwidth for any particular signal on in STS, VT, or cell or packet basis.

Abstract: In one aspect, the present invention provides a method of communicating across a serial line 26. In this method, n parallel streams of data 30 are to be received at a destination 20. In a first embodiment, the n parallel streams of data 30 characterized in that one of streams of data includes a unique characteristic that can be used to distinguish that one from each of the other streams of data. In a second embodiment, each of the n streams of data 30 are in a particular pattern that includes a detectable characteristic. At the destination 20, the unique characteristic and/or detectable characteristic can be detected to correct space and/or time errors in the streams of data. For example, the destination 20 might be a receiver that includes a serial-to-parallel converter 28 and calibration circuitry 34.

Abstract: A method of determining end points for an optical channel in an optical network to off-load traffic from a target optical link is provided. The method includes the steps of identifying ingress network nodes sourcing traffic through the target optical link, and determining an average ingress bandwidth sourced by the ingress network nodes. Thereafter, the method includes the steps of identifying egress network nodes sinking traffic from the target optical link, and determining an average egress bandwidth sunk by the egress network nodes. The optical channel start point candidates are identified to include ingress network nodes sourcing more traffic than the average ingress bandwidth, and the optical channel end point candidates are identified to include egress network nodes sinking more traffic than the average egress bandwidth.

Abstract: A system for integrated testing of one or more multi-service communications switches including a script execution environment for executing a test script. The script execution environment includes a hardware definition file storing a number of logical hardware device names corresponding to hardware devices used by the test script, including a system under test (SUT) and a number of hardware testing devices. The system further employs a network definition file including a plurality of logical connection names corresponding to connections between the hardware devices in the test environment. These connections in the network definition file are specified in terms of the logical hardware device names defined in the hardware definition file.

Abstract: A method of configuring a SONET network element to support a test head test session comprises dedicating an otherwise assignable output port of a SONET network element as a test access port, receiving a request to connect a connection switched by a switch fabric of the SONET network element to the test access port, determining whether the request is associated with a test head; and, if the request is associated with the test head, provisioning the switch fabric to connect the connection to the test access port.