Abstract: A timing circuit for use with transport logic in a network element is provided. The network element forms part of a data network and the timing circuit includes a timing receiver having a timing input, a timing output, and a selection input, the timing receiver operable to receive one or more timing signals at the timing input and to select a selected timing signal for distribution to the transport logic via the timing output based on a selection signal received at the selection input. The timing circuit also includes a determination circuit that is operable to determine whether the timing circuit is one of a master timing circuit and slave timing circuit, and based on the determination, produce the selection signal. A sync transmitter is also included in the timing circuit. The sync transmitter is coupled to the timing output, the determination circuit, and a communication channel.

Abstract: Methods and apparatuses for laying out an integrated circuit include a first plurality of I/O ports that are positioned along the first side, a plurality of queues that are coupled to the first plurality of I/O ports, a first bus that is positioned extending from the plurality of queues toward the second side to couple a control circuit to the plurality of queues, second plurality of I/O ports that are positioned along the third side and the fourth side, and a second bus that is positioned between the control circuit and the second plurality of I/O ports to couple the control circuit to the second plurality of I/O ports, wherein the first bus and the second bus are positioned such that the respective bus lines do not cross over each other. A time and space switching apparatus and component cell permit a bit within a data line to be selected.

Abstract: The present invention provides a system and method for communicating data between network subsystems over optical fibers using a backchannel probe signal. In one embodiment, the present invention includes an optical network having an optical fiber coupled between first and second optical couplers residing in two different subsystems. A first processing unit is coupled to a first tap of the first optical coupler for providing an optical payload signal, and a second processing unit is coupled to a first tap of the second optical coupler for receiving the optical payload signal. A probe signal transmitter is coupled to a second tap of the second optical coupler for providing a probe signal, and a probe signal receiver coupled to a second tap of the first optical coupler for receiving the probe signal. The probe signal may be used to detect erroneous fiber connections or lossy inter-subsystem fibers.

Abstract: A distributed method and system of controlling a communications network having a plurality of spans of interconnected network elements some of which include a network element processor distributes network topology information to respective span databases; stores original fault objects in the respective span databases; advertises fault objects to other network element processors in a local span when the original fault affects network elements other than a network element in which the fault occurred; advertises alarm objects to other network element processors that are respectively associated with a circuit affected by the original faults; stores the advertised fault and alarm objects in the respective span databases; and performs distributed processing of the advertised fault and alarm objects with the other network element processors and the respective span databases.

Abstract: A digital information mapper and method for mapping sequences of information characters into a SONET (synchronous optical network) payload in such a manner that there can be an arbitrary mixture of control and/or data values in those sequences. Each information character comprises 9 bits consisting of an 8 bit information byte, being either a control byte or a data byte, and one octet type bit identifying the byte as control or data. A processor applies a mapping algorithm of a mapping module to the input information characters. The mapping algorithm is applied to sequences of eight input information characters, the algorithm being operable to map the information bytes of each sequence of eight information characters to eight of a sequence of nine contiguous SPE octets. The algorithm then maps the octet type bits for the eight mapped information bytes of the character sequence to the ninth octet of the contiguous SPE octets of the SPE octet sequence.

Abstract: The present invention provides a system and method for effective troubleshooting of a network. In one embodiment, the present invention provides a system for troubleshooting a network having a plurality of network elements. A management station may be coupled to one of the network elements for signaling a distributed network operating system to transmit alarm information from each network element to the management station for display to a user. The system also includes a plurality of network element subsystems in each network element, wherein at least one of the plurality of network element subsystems generates a subsystem alarm in response to a subsystem fault condition. The distributed network operating system includes a plurality of subsystem applications on each network element, wherein at least one of the subsystem applications on each network element generates an application alarm in response to receiving the subsystem alarm.

Abstract: A method and system for emulating the optical behavior of an optical communications generates wavelength modeled objects for each emulated optical signal and a variety of other modeled objects for the optical communications modules of the emulated system such as transmitter modeled objects, a combiner modeled object, an amplifier modeled object, a splitter modeled object, and receiver modeled objects. Each of the modeled objects includes certain optical attributes and a behavior modeling function particular to the module being emulated. The optical modules themselves are also represented as emulated processes. The modeled objects are propagated along a logical path from emulated process to emulated process. Upon receipt of a modeled object the emulated process executes the behavior modeling function and updates modeling objects affected by the execution.

Abstract: A recessed cable management assembly for use in an interconnect assembly. The cable management assembly includes a cassette having a spool for receiving and retaining a length of a cable. A substrate includes an interconnect connector which is coupled to the cable. The substrate includes a cut-out sized to receive the cable management assembly such that the cable management assembly is recessed within the substrate.

Abstract: An electronic system includes a backplane, a first plurality of slots coupled to the backplane, the first plurality of slots having a first electrical interface to be coupled to electrical circuit cards of a first type, wherein the electrical circuit cards of the first type receive network data and convert the network data to SONET formatted data, and a second plurality of slots coupled to the backplane, the second plurality of slots having a second electrical interface to electrical circuit cards of a second type. The backplane routes data signals between the first plurality of slots and the second plurality of slots.

Abstract: Consistent with the present invention, a tunable laser emits a monitoring signal which is combined with the WDM channels typically at the transmit side of a WDM system. At each monitoring point along the WDM system, the WDM channels are filtered out, the monitoring signal is sensed, and desired systems parameters (e.g., gain flatness, dispersion, PMD and OSNR) are measured. Accordingly, a single tunable element, i.e., the tunable laser, can be provided, thereby reducing costs. Moreover, system performance can be ascertained regardless of whether WDM channels are present.

Abstract: A method and apparatus for servicing massive interrupts in random access memory (RAM) are provided, comprising receiving a massive interrupt signal, and reading at least one unit interrupt register in a first RAM area in response to the massive interrupt signal. A set unit interrupt bit corresponds to an address in a second RAM area. Interrupt status registers are read at the corresponding address in the second RAM area in response to the set unit interrupt bit. A set interrupt status bit corresponds to an address in a third RAM area. Interrupt cause bits are read at the corresponding address in the third RAM area in response to the set interrupt status bit, and detailed information is obtained about the interrupt. The interrupt is serviced in accordance with the detailed information.

Abstract: A user interface for managing connections in a communication network cross connect. The user interface provides for creation, viewing and removing connections in the cross connect. When displaying connections, a slice value and granularity may be adjusted to allow for effective viewing of connections having high data rates. The user interface may include a search tool for locating connections and/or a protection setup routine to facilitate establish protection connections.

Abstract: Consistent with the present invention, programmable input and output buffers are provided on each port of each stage of a distributed system in order to reduce data skew and preserve data synchronization. The programmable buffers provide the ability to add delay to data paths having less skew to compensate or match the skew associated with data paths having greater skew. Accordingly, the programmable buffers can equalize data skew and preserve data synchronization at each stage in the distributed system. As a result, individual stages can be placed farther apart, thereby facilitating larger distributed systems.

Abstract: A distributed method and system of controlling a communications network having a plurality of spans of interconnected network elements some of which include a network element processor distributes network topology information to respective span databases; stores original fault objects in the respective span databases; advertises fault objects to other network element processors in a local span when the original fault affects network elements other than a network element in which the fault occurred; advertises alarm objects to other network element processors that are respectively associated with a circuit affected by the original faults; stores the advertised fault and alarm objects in the respective span databases; and performs distributed processing of the advertised fault and alarm objects with the other network element processors and the respective span databases.

Abstract: A virtual oven efficiently conducts stress testing of large numbers of modules. The virtual oven includes a logical grouping of modules, a controller, test instruments and a database which are all connected via a network. The logical groupings of modules of several virtual ovens may be physically accommodated within a single environmental stress screening room. Switching between modules in a logical group permits a single test piece of test equipment to be time-shared among the modules in the logical group. The method of bum-in testing a logical group of modules rotates a test sequence, including passive and active test cycles, between the modules. A test signal is split and supplied to multiple modules. Passive testing may be performed by monitoring parameters of the module while the test signal is supplied to the module. Active testing may be a functional test of the module in which the test signal is supplied to, processed by, and output from the module.

Abstract: A service channel modem is adapted to determine optical properties of an optical fiber link connecting two nodes. The optical service channel (OSC) communicates an optical reference parameter over the fiber link. An optical parameter of the OSC transmitted over the fiber link is measured. By recovering the optical reference parameter from the OSC and using the measured optical parameter, certain optical properties may be determined including link loss, multi-path interference, and chromatic dispersion. When measuring chromatic dispersion, one of the fiber links serves as a synchronization reference and the other is the link being measured.

Abstract: This invention relates to a method and apparatus for controlling the flow of fiber channel (FC) data frames from a fiber channel link to a metropolitan area link of lesser bandwidth (a synchronous optical network (SONET)). The release of each data unit by a data source for transport onto the first channel is governed by a credit-based protocol whereby one data unit is released upon the provision of one credit unit. A first marker identifies a high limit H of the buffer at which a first condition occurs, H being less than N and the first condition applying when the number of data units in the buffer is greater than H. A second marker identifies a low limit L of the buffer at which a second condition occurs, L being less than H and the second condition applying when the number of data units in the buffer is less than L. A credit unit owed counter O counts the number of credit units which become owed to the data source when the second condition applies.

Abstract: An optical device including dynamic channel equalization is provided. In an exemplary multiplexer or line amplifier configuration the device includes a plurality of separate optical paths, each of which receiving a separate group of optical signals. Each group of optical signals is provided to an associated variable optical attenuator. Separate inputs of an optical combiner are each coupled to an output of an associated one of the variable optical attenuators. The optical combiner has an output providing the separate groups of optical signals in an aggregated form on an aggregate optical signal path. An optical performance monitor is coupled to the aggregate optical signal path, and is configured to detect an optical signal power of each of the separate groups. The monitor supplies a feedback signal to corresponding ones of the variable optical attenuators for adjusting a respective attenuation associated with each of the attenuators in dependence of the detected optical signal powers.

Abstract: An optical filter aligner/separator device for retaining optical filters in a desired position, the optical filters having an optical filter height, the device includes: a top frame having a top frame cut out section; a bottom frame having a bottom side and a bottom frame cut out section, the bottom frame coupled to the top frame, the bottom frame cut out section aligning with the top frame cut out section; and a wire mesh disposed between the top frame and the bottom frame, the wire mesh disposed at the cut out section, the wire mesh having a height from the bottom side of the bottom frame that is less than the optical filter height.

Abstract: A first network element includes or is associated with a query engine that allows it to retrieve operating parameters from a second network element even when the first and second network elements are not participating in a common routing protocol. The first element is thereby able to determine if the second network is operational and to take action to reroute data to a backup element if the second element is not operational.