Abstract: A loop locating apparatus and method enabling simple and fast identification of a Layer 3 loop fault occurring in a network, wherein, when the possibility of a Layer 3 loop is detected, a loop locating command function unit makes a packet transmission/reception function unit send a series of inspection packets (Pis) with successively incremented TTLs and monitors the return packets (te) of the inspection packets (Pis) by a return number counting function unit and wherein a loop location decision function unit finds the routers returning packets (te) with remarkably larger return numbers than the others and identifies the routers with return numbers over a predetermined threshold as the location of occurrence of the loop.

Abstract: The present invention discloses an automated testing solution for PRL's, System Acquisition algorithm, and CDMA device performance. A testing plan loads a specific PRL into a test device, reads and categorizes the entries in the PRL file, and then uses the information to set the parameters on the emulation hardware needed for each test case. The testing solution allows an operator to specify the PRL file to be used for testing and the testing plan will determine the relationships between different PRL entries in the test file including the System of equal priority in the same GEO, System of lesser priority in the same GEO, System of higher priority in the same GEO, Systems in different GEO, and Collocated EVDO systems. Once the entries are categorized the test script will then select the entries need to create the required test conditions on the base station emulation hardware. The test suite employs base station emulation hardware to create the RF conditions stipulated in the test case.

Abstract: In one embodiment, an initiating maintenance end point (MEP) may transmit a lock message to lock a circuit traversing one or more maintenance intermediate points (MIPs) between the initiating MEP and an end MEP. The initiating MEP may then transmit an in-band packet containing a loopback request to a particular MIP along the circuit using a particular time-to-live (TTL) value in the packet to reach the particular MIP. Upon receiving the packet at the particular MIP, and in response to determining that the TTL has expired, the particular MIP inspects the packet to discover the loopback request, and correspondingly operates in a loopback mode.

Abstract: A transmission delay measuring circuit may include a first transmission path, a second transmission path, an inversion circuit, a first multiplexer, and an output terminal. The second transmission path may have the same structure as the structure of the first transmission path and may receive the output of the first transmission path. The inversion circuit may invert the output of the second transmission path. The first multiplexer may output one of the external input signal and an inverted output of the second transmission path to the first transmission path in response to a test mode enable signal. The output terminal may output, as a measuring signal, a signal in an arbitrary node of a closed loop formed of the first transmission path, the second transmission path, the inversion circuit, and the first multiplexer. The transmission delay measuring apparatus may more accurately measure the transmission delay of a transmission path in a semiconductor device in a die-to-die wafer state or a package state.

Abstract: The present invention relates to a packet switch and a packet switching method. An example embodiment of the present invention comprises at least three network ports, at least one instrument port, a mux-switch, a packet switch fabric, and an address table. The embodiment updates the address table to include the source address of each ingress packet of each network port and associate the source address with that network port. The mux-switch routes the ingress packet traffic of each network port according to the identity of the network port so that at least a copy of the packet traffic of one of the network ports is routed to an instrument port. The packet switch fabric routes the packets from the instrument ports to the network ports according the destination address of the packet and the identity of the network port that is associated with the destination address as recorded in the address table.

Abstract: A daisy chained ethernet network data acquisition system for use in industrial processes is shown. The system employs standard category five twisted-pair connectors, each having four twisted-pairs associated therewith. Two of the twisted-pairs are employed for transmitting and receiving command signals and data, while the remaining two are employed for transmitting a common clock and synchronizing signal to each of the various stages of the processing line at which data is to be acquired. The system thus allows for the time correlated acquisition of data from a plurality of stages or stations of a lengthy processing line by employing ethernet interconnection.

Abstract: Embodiments of the present invention provide a protocol tester for performing a protocol test, said protocol tester exhibiting an input for the feeding in of data, a protocol decoding device for the decoding of data, and an output for providing the decoded data, the protocol tester also comprising a device for measuring the bit error rate. A corresponding method for performing a protocol test is also provided.

Abstract: A method of and a system for autonomously identifying which node in a two-node system has failed are described. The system includes two nodes and a fault-tolerant communication fabric. The fabric defines a plurality of communication paths connecting the two nodes, and fault-tolerant loop-back communication in which each node can send a message to itself utilizing at least one switch structure of the fabric. In addition, each of the two nodes includes logic for performing the service; logic for testing the functionality of the respective node; logic for sending test result messages to both nodes; fault-isolation logic for analyzing test result messages from both nodes; and logic for disabling the other node from performing the service only if the fault-isolation logic determines that the respective node is capable of successfully performing the service and also determines that the other node is incapable of successfully performing the service.

Abstract: A method for testing a data packet transceiver as a device under test (DUT) by communicating, between one or more test instruments and the DUT, multiple data packets having at least one mutually distinct signal characteristic, such as data packet type, transmission power or transmission frequency.

Abstract: Packet switch operating methods and packet switches receive a packet on a first port of the packet switch. The packet is addressed to a device that is in communication with a second port of forwarding circuitry of the packet switch and the packet has an Ethernet destination address field and an Ethernet source address field. The Ethernet destination address field includes a first address and the Ethernet source address field includes a second address. The methods and packet switches also forward the packet to an output queue associated with a third port of the forwarding circuitry, forward the packet from the output queue to the first port, and modify the packet so that the Ethernet destination address field comprises the second address instead of the first address.

Abstract: An apparatus and method for performing automated testing and trouble isolation of a communications link in an access network is described. Communications link testing may occur without taking the communications link out of service for the duration of the test.

Abstract: A system and method for self-test of an integrated circuit are disclosed. As one example, an integrated circuit is disclosed. The integrated circuit includes a digital signal processing chain, a random sequence generator coupled to an input of the digital signal processing chain, and a checksum calculator coupled to an output of the digital signal processing chain.

Abstract: A method for processing fault dependency of different levels of tandem connection monitoring is provided. The method comprises obtaining monitored coverage scopes of the different levels of tandem connection monitoring (TCM); locating a fault section according to an overlapping relationship between monitored coverage scopes of the at least two different levels of TCM at which the warnings are reported and performance degradation degrees of the at least two different levels of TCM, the fault section being located when warnings are reported in at least two different levels of TCM; and outputting location-related information that includes information of the fault section to a user.

Abstract: A network testing system for a device under test (DUT) uses a test tool to generate test packets provided to the DUT as source traffic and to receive the test packets back from the DUT as destination traffic. Before the test packets are returned from the DUT to the test tool, an external router receives the test packets from the DUT and forwards them back to the DUT. The DUT has a first pair of DUT interfaces coupled to the test tool and a second pair of DUT interfaces coupled to the external router. The DUT has a first virtual router with a first routing table configured to direct test packets received on one of the interfaces in the first pair of DUT interfaces to the external router. The DUT has a second virtual router with a second routing table configured to direct test packets received on one of the interfaces in the second pair of DUT interfaces to the test tool. Thus, test packets output by the test tool traverse the DUT more than once before returning to the test tool.

Abstract: A communication path is set from an ingress node to an egress node on the basis of a specified path setting protocol, and a loopback-test signal is transmitted to the egress node through the communication path so as to perform a loopback-test on the egress node. The ingress node receives a loopback-test response signal transmitted from the egress node on which the loopback-test has been performed, and determines whether or not a loopback-test on the egress node has ended normally by analyzing the received loopback-test response signal.

Abstract: A loopback test to test a communication link for a layered interface where in a master agent programs the electrical parameters for the slave agent, such as, the offset, timing, and current compensation with a loopback control register.

Abstract: In one embodiment, a first node may send an out-of-band message to a second node to request that the second node initiate an in-band echo request for a specified tunnel, e.g., toward one or more third nodes. Upon receiving the in-band echo request, one or more responding nodes (e.g., generally the third nodes) may send a response to the first node. This “directed echo request” technique may also be used in conjunction with a “reverse traceroute” technique.

Abstract: A method of calculating a bandwidth for a mobile terminal including requesting, by the mobile terminal, a description of a streaming content from a network and receiving a response from the network, requesting, by the mobile terminal, a Quality of Service (QoS) value corresponding to a required amount of bandwidth resources of the network for receiving a streaming service of the contents from information about the content included in the received response, and receiving, by the mobile terminal, allocated bandwidth resources of the network according to the QoS value.

Abstract: An internal loop-back architecture for a parallel serializer/deserializer (SERDES) includes a transmitter macro including a plurality of transmit elements arranged in a parallel architecture, and a receiver macro including a plurality of receive elements arranged in a parallel architecture, wherein at least a portion of the transmit elements and a portion of the receive elements share a communication channel and wherein any of the plurality of transmit elements in a row can communicate with any of the plurality of receive elements in a row, and wherein each of the plurality of transmit element includes a loop-back arrangement with each of the plurality of receive elements.

Abstract: A method and system for multiplexing a plurality of serialized data signals in which a first integrated circuit device generates a plurality of serialized data signals. A second integrated circuit device is in electrical communication with the first integrated circuit device. The second integrated circuit device includes a multiplexer operable to generate a multiplexed output signal from the plurality of serialized data signals received from the first integrated circuit. A phase data and byte snapshot back channel is transmitted from the second integrated circuit device to the first integrated circuit device. The phase data and byte snapshot back channel carries phase data and periodic snapshots of the serialized data signals. The phase data and byte snapshot back channel is used by the first integrated circuit device to adjust the phase of each of the plurality of serialized data signals to preserve bit and byte alignment. Such a method and system can be implemented as a 4×10 Gbit/Sec.

Abstract: Example methods and apparatus to pre-qualify user communities for communication services are disclosed. An example method comprises configuring a first remote network demarcation associated with a first loop to a loop-back state, interrogating the first loop to determine a first parameter representative of the first loop, configuring a second remote network demarcation associated with a second loop to the loop-back state, interrogating the second loop to determine a second parameter representative of the second loop, and compiling a report based on the first and second parameters, the report containing a value that represents a degree to which a communication service can be provided to a user community associated with the first and second loops.

Abstract: A localization process in a network of source devices and sink devices on a 1394 bus, is performed by a source device while it is communicating to a sink device, which determines local network links from nonlocal ones. An actual round trip time calculation is performed only by the source device and the sink device can be relatively passive. The duties of the sink device are performed in hardware and involve (trivially) modifying the received message while moving the message from the input isochronous channel buffer to the output isochronous channel buffer.

Abstract: A system and method for transmitting DS3 signals over long distances over a plurality of twisted pair conductors is provided. A DS3 interface is provided. The DS3 signal is inversely multiplexed into a plurality of data streams. Overhead is added to the data streams to generate packets having stream identifiers and packet number identifiers. At the receive end, received packets are synchronized using the stream and packet number identifiers, and multiplexed back into a DS3 signal. Systems according to embodiments of the invention are compatible with existing loopback codes, passing through a first loopback code received, and optionally entering a loopback mode where more than one loopback code is received consecutively without an intervening loop down code being received. The incorporated technology permits very small packaging and thereby permits use in small outdoor enclosures.

Abstract: Disclosed is a method and apparatus for improving LAN availability and robustness employing adjacency status self-discovery on segment-to-segment communications paths. In some embodiments, the method and system may employ Logical Link Control Type 1 test frame messages between segment nodes to determine status. Adjacent node status may be determined by waiting a period of time for an acknowledgment message and marking the tested link as “down” if no response is received. Also disclosed is a method for compacting data transmitted over a network to reduce overhead.

Abstract: Disclosed is a system method and software for user customizable device insertion. A new device is to be inserted in a loop based network such as an FC-AL network. The network is facilitated by a dedicated networking element, such as a switch. In order to ensure that the new device does not adversely affect the network, the new device is tested before it is inserted. Several tests are provided and the user is allowed to choose which tests are to be used. Alternatively, the user is allowed to define his/her own tests. The device is inserted into the network only after it has satisfactorily completed the applicable tests.

Abstract: A transfer path in a router is set in a loop shape by a test processing unit. In a NP chip (network processor), decrement of a TTL value is inhibited by a test processing unit, and a routing table is set such that data are transmitted in order along the transfer path of the loop shape. Consequently, the test processing unit circulates a predetermined number of data on the transfer path of the loop shape, and inspects the data circulated.

Abstract: There is provided communication device operable to verify normality of a network by a loopback test, the communication device including a plurality of ports used to connect to a physical link included in the network, and an identification information addition part to add virtual port information used to identify a virtual port to a reply frame when receiving a message frame to the virtual port set on the physical link, the message frame being used to verify normality of the network by the loopback test, and replying the reply frame in which the virtual port information is added, to a communication device that has transmitted the message frame.

Abstract: A method to increase the capacity efficiency of span-restorable mesh networking on sparse facility graphs. The new approach views the network as a “meta-mesh of chain sub-networks”. This makes the prospect of WDM mesh networking more economically viable than with previous mesh-based design where the average nodal degree is low. The meta-mesh graph is a homeomorphism of the complete network in which edges are either direct spans or chains of degree-2 nodes. The main advantage is that loop-back type spare capacity is provided only for the working demands that originate or terminate in a chain, not for the entire flow that crosses chains. The latter “express” flows are entirely mesh-protected within the meta-mesh graph which is of higher average degree and hence efficiency for mesh restoration, than the network as a whole. Nodal equipment savings also arise from the grooming of express lightpaths onto the logical chain-bypass span. Only the meta-mesh nodes need optical cross-connect functionality.

Abstract: A method for loadbalancing in a network environment is provided that includes receiving a request from an end user for a communication session at a central node. The method further includes identifying a selected one of a plurality of network nodes to facilitate the communication session for the end user based on feedback information provided by the selected network node. The feedback information is communicated from the selected network node and processed before making a decision to establish the communication session between the selected network node and the end user.

Abstract: An apparatus and method for performing automated testing and trouble isolation of a communications link in an access network is described. Communications link testing may occur without taking the communications link out of service for the duration of the test.

Abstract: Redundant acknowledgment between agents performing a loopback test over bidirectional communications bus is described. In one example, in a processor including a communications agent coupled to a bidirectional communications bus, the communications agent initiates loopback communications to a second agent, sends a packet including a redundant acknowledgment sequence to the second agent, receives the packet including the redundant acknowledgement sequence looped back from the second agent, determines whether the received redundant acknowledgment sequence is valid, sends a test sequence to the second agent, receives the test sequence looped back, and if the received redundant acknowledgment sequence is determined to be valid, then checks the received test sequence.

Abstract: The present invention discloses a performance management system, apparatus and method between a Residential Gateway (RG) and a Broadband Remote Access Server (BRAS), the method thereof includes: configuring an OAM IWF for the protocol conversion between the performance management message of the Asynchronous Transfer Mode (ATM) Operation, Administration and Maintenance (OAM) protocol or the point-to-point Ethernet OAM protocol and the performance management message of the service layer Ethernet OAM protocol in a Digital Subscriber Line Access Multiplexer (DSLAM), when the performance management is performed in a broadband IP network, after the OAM IWF configured in the DSLAM performing the protocol conversion of performance management message, performing the end-to-end performance management between an RG and a BRAS according to the performance management message with the converted protocol.

Abstract: A loop detection system and method operable in an Ethernet network having a provider network and a customer network. In one embodiment, a provider edge (PE) entity is operable to generate a test frame with at least one of a destination address (DA) and source address (SA) that is unknown to the customer network. The test frame is broadcast to the customer network coupled to the PE entity. Upon determining that the test frame or its duplicates are received back by the PE entity within a first time period, loop location within the Network is deduced responsive to the determination.

Abstract: A method, system and apparatus are provided for detecting a loop-back in a physical layer on an Ethernet link. In the physical layer, a device sends a base page on the Ethernet link. The base page has at least one next page capability bit set. Subsequently, the device receives a received base page. Thereafter, for detecting the loop-back, the next page capability bit is set in the received base page is determined.

Abstract: A management data distribution apparatus has, a control unit, a buffer memory element, at least one input port, and a telecommunications output. The at least one input port is arranged to receive management data from devices located within a network and to pass the management data to the control unit. The control unit is arranged to control output of the management data via the telecommunications output to a remote monitoring site over a telecommunications network. The control unit is also arranged to store management data arriving at the at least one input port when the said telecommunications output is in use in the buffer memory element, temporarily.

Abstract: A transmission destination of a packet to be transmitted by a web server (11) and an application server (21) incorporated in the same machine (30) is set to a loopback device (50). When a packet is received from one of the servers (11 and 21), the loopback device (50) decides whether or not a combination of a source IP address, a source port number, and a destination port number in the packet is known. If the combination is known, the source IP address and a destination IP address of the received packet are exchanged, and the packet is transmitted to the other server. Further, the packet received from the one of the servers and the packet transmitted to the one of the servers are copied, and the copied packets are transmitted to a communication state visualizing machine (90).

Abstract: According to one embodiment, a method for testing a circuit includes receiving a test access session request, where the test access session request indicates that a test session is to be performed on a circuit path. A reservation message is sent to a test bus, where the reservation message reserves the test bus for the test session. The test bus includes a portion of bandwidth shared among a plurality of network elements. Traffic associated with the circuit path is copied to the test bus.

Abstract: A system and method in a communications network of testing a communications link between Customer Premises Equipment (CPE) and a Broadband Remote Access Server (BBRAS). The CPE and BBRAS communicate mutually via an intermediate Internet Protocol Digital Subscriber Line Access Multiplexer (IPDSLAM). The CPE is connected to the IPDSLAM via an Asynchronous Transfer Mode (ATM) link, and the BBRAS is connected to the IPDSLAM via an Ethernet link. When a customer complaint is received in a Customer Care Center (CCC), the IPDSLAM is instructed to test the link. The IPDSLAM executes a first loop-back test with the CPE according to the ATM standard, and executes a second loop-back test with the BBRAS according to the Ethernet standard. The results of the first and second loop-back tests are reported to the CCC.

Abstract: An electronic device (120) is provided that comprises: a transceiver circuit (310) configured to send and receive signals; a memory unit (330) configured to contain testing, configuration, and calibration (TCC) code (440, 450, 460) used to define TCC functions in the device, and operational code (470) used to define operational functions in the device; and a device controller (320) connected to the transceiver circuit and the memory unit, configured to control the device in an operational mode in accordance with the operational code and operational instructions received via the transceiver circuit (650), and to control the device in a TCC mode in accordance with the TCC code and TCC instructions received via the transceiver circuit (635, 640). The device controller is further configured to permanently disable access to at least a portion of the TCC code in response to a disable instruction received via the transceiver circuit (645).

Abstract: A network loop monitor (10) is disclosed which comprises an RS485 port (16) for connection to a host which receives and transmits data. The port (16) comprises termination jumpers (14), a transmitter/receiver (34) and an isolator (36). The monitor (10) includes two further RS485 ports (18, 20) each of which has a termination (26, 28), a transmitter/receiver (42, 44) and an isolator (38, 40). A relay (22) controls contacts (24) in the line pair (12). Router logic (32) controlled by a microprocessor (30) determines the status of the loop monitor.

Abstract: The present invention provides a small form factor, pluggable ONU, which includes a bi-directional optical transceiver configured to transmit optical signals to and receive optical signals from an OLT. The ONU further includes an ONU chip coupled to the optical transceiver and configured to communicate with the OLT. Also included is a pluggable interface configured to electrically interface between the ONU chip and a piece of subscriber premise equipment (SPE). The ONU includes a power management module to provide power to the ONU chip and the optical transceiver, using power delivered from the SPE through the pluggable interface. The ONU is enclosed a small form factor enclosure, thereby allowing the pluggable ONU to be directly plugged into the SPE and providing an Ethernet Passive Optical Network (EPON) uplink to the SPE without requiring an separate power supply.

Abstract: Disclosed is a method for estimating an available bandwidth of a network. A plurality of periodic time-stamp packets are transmitted to a receiving-party communication apparatus, which is connected to the network, through the network at a currently-set test transmission rate, and then a changing tendency of transmission delay time differences between the time-stamp packets is checked on the basis of reception times at which the receiving-party communication apparatus have received the respective time-stamp packets. When the transmission delay time differences are located outside a stable range and show a tendency to increase, the test transmission rate is set to a decreased value and the time-stamp packets are repeatedly transmitted at the decreased rate and when the transmission delay time differences are located outside the stable range and show a tendency to decrease, the test transmission rate is set to be an increased value and the time-stamp packets are repeatedly transmitted at the increased rate.

Abstract: An audio network system allows any two nodes among a plurality of nodes to transmit and receive audio data to and from each other. The plurality of the nodes are connected in loop so as to allow transmission of the audio data in loop manner through the plurality of the nodes, and the transmission of the audio data is performed in one direction from an upstream node to a downstream node. One of the plurality of the nodes is set as a master node and the other nodes are set as slave nodes. The master node periodically transmits a packet of frame data containing the audio data every sampling period, such that the packet transmitted from the master node circulates through the plurality of the nodes to return to the master node within one or more sampling period. The packet has a specific data length and includes an audio data storage region divided into a plurality of blocks corresponding to a plurality of channels, such that each of the blocks stores audio data of the corresponding channel.

Abstract: A broadband test line-access board includes at least two broadband test line-access units. Each of the at least two broadband test line-access units includes first, second, and third test terminals, a signal splitter, first, second, and third switches, and first second and third interface terminals. The broadband test line-access board further includes a set of inner test buses, including an internal inner-test bus, an internal outer-test bus and an internal auxiliary-test bus, and fourth, fifth, and sixth switches, and a low-pass filter.

Abstract: A data transmitting apparatus including a transmitting unit connected to a first network and configured to transmit a check packet to a data receiving apparatus; a control unit configured to receive an acknowledgment message to the check packet from the data receiving apparatus, the acknowledgment message including acknowledgment information based on shared data shared with said data receiving apparatus; a computing unit configured to compute an expected acknowledgment information based on the shared data shared with said data receiving apparatus; a comparing unit configured to produce a comparison result for said data receiving apparatus based on the acknowledgment information and the expected acknowledgment information; a timer configured to determine whether a response time of the acknowledgment message is less than a predetermined time; and a judgment unit configured to judge whether to stop transmission of content data based on the comparison result and the determination of the timer.

Abstract: A packet forwarding device is disclosed. The packet forwarding device includes: a transmission interface, coupled to a second network device; a processing unit, coupled to a first network device; a forwarding unit, coupled between the transmission interface and the processing unit; and an interface loop-back, coupled between the forwarding unit and the processing unit.

Abstract: A network switching device comprises first and second ports. A queue communicates with the second port, stores frames for later output by the second port, and generates a congestion signal when filled above a threshold. A control module selectively sends an outgoing flow control message to the first port when the congestion signal is present, and selectively instructs the second port to assert flow control when a flow control message is received from the first port if the received flow control message designates the second port as a target.

Abstract: Redundant acknowledgment between agents performing a loopback test over bidirectional communications bus is described. In one example the acknowledgment is performed by initiating loopback communications from a first agent to a second agent, sending a packet including a redundant acknowledgment sequence from the first agent to the second agent, receiving the packet including the redundant acknowledgement sequence looped back from the second agent at the first agent, sending a test sequence from the first agent to the second agent, and receiving the test sequence looped back from the first agent.

Abstract: An embodiment includes a method of minimizing the delay in convergence time for a complex STP topology following a topology change in the network system in the spanning tree protocol (STP) standard, including: receiving, by a root port of a first bridge, a data message that includes identification of a current root bridge and a priority value of the current root bridge; receiving, by a second port of the first bridge, a second data message from a second bridge; and if a message age timer of the first bridge has less than a limiting message age time value remaining before expiry, then blocking a reply, by the second port of the first bridge, to the second data message from the second bridge.

Abstract: A request-packet transmitting unit transmits a predetermined number of request packets having a non-unicast destination address that can be received by a target network including a network identified by a first network address, from a monitoring network identified by a second network address different from the first network address through a layer 3 relay device. A layer 2 loop detecting unit receives response packets corresponding to transmitted request packets through the layer 3 relay device, and detects a layer 2 loop in the target network based on number of received response packets and number of transmitted request packets.