Abstract: A technique for managing loops between network devices such as customer and carrier edge devices involves monitoring the MAC moves that occur at a device to detect the existence of a loop and initiating a loop protection action if the MAC moves indicate that a loop exists. The number of MAC moves that indicates the existence of a loop is user programmable and pre-established in the device configuration. The number of MAC moves can be expressed as a MAC move threshold, which is defined in terms of, for example, a MAC move rate or a number of MAC moves. Typically, the loop protection action that is initiated in response to a detected loop involves blocking the flow of the looping packets at the corresponding device.

Abstract: A system and method for resuming an interrupted flow of data packets from a sender to an intermediate node in a path between the sender and a mobile device includes a first step 102 of storing a history of data packets sent to the mobile device. A next step 104 includes interrupting the flow of data packets. A next step 106 includes providing a sequence number pointers in a flow control protocol to the restart sequence number determining processor, the sequence number pointers indicating a best position in the flow of data packets for restarting packet flow. A next step 108 includes resuming the flow of data packets from the history starting at a packet indicating by the sequence number pointer decided by the restart sequence number determining processor.

Abstract: A system and method for coupling a communications device to a primary communications network having a first communications format and to a secondary communications network having a second communications format, such that the communications device is configured for having an assigned device identification and configured for using an assigned network address for use in routing data over the primary communications network. The system and method can comprise a first port configured for connecting to the communications device, a second port configured for connecting to the primary communications network and facilitating the communication of the data between the primary communications network and the communications device through the first port, and a third port configured for connecting to the secondary communications network and facilitating the communication of the data between the secondary communications network and the communications device through the first port.

Abstract: Redundant gateway methods, apparatus and systems use more than one gateway device in a gateway device group for communications directed outside of a LAN. Failover services in the event that an active router or other gateway device fails. In determining the priority of members of the group to become the active router/device for the group, a route metric is used as the priority value in elections held to determine the operating mode of each group member. This route metric is a numerical value representing the optimality of a route available between the router and a destination such as a remote network. By comparing the members' respective route metrics from time to time and in the event of a trigger event, the active router/device in a group is guaranteed to be the router with the optimal route to that remote network.

Abstract: Methods and systems for hitless switch management module failover and upgrade are disclosed. According to one method, a master switch management module participates in network protocols and performs packet forwarding operations. The master switch management module distributes protocol state and packet forwarding information to the slave switch management module. The slave switch management module continuously monitors the operational state of the master switch management module. In response to detecting failure of the master switch management module or a forced failover initiated by the user interface on the master switch management module, the slave switch management module begins network protocol operation in the master mode in a state where the master switch management module last operated correctly.

Abstract: The present invention is directed to the maintenance of call signaling information in connection with realtime communications established using a packet data network. According to the present invention, call state information related to a realtime communication is provided by a call controller to an interconnected client. The client stores the call state information. In the event of a failure of a call signaling channel between the call controller and the client or in the event of a failure of the call controller, the client may establish contact with an alternate call controller, and may provide the call state information that has been stored on the client to the alternate call controller. The alternate call controller may then restore call features associated with the realtime communication.

Abstract: The invention relates to a method and device for medium-redundant operation of a terminal in a network.

Abstract: A portable distributed application framework that uses a definition file describing a structure of data and commands to be used by the framework to interface with an application. A proxy, responsive to a definition file, creates and receives messages based on the definition file. The created messages contain data and commands used to control the application while the received messages contain data from the application. A control, responsive to the definition file, relays messages between the proxy and the application. A housing, responsive to the definition file and the messages from the proxy, provides the application with configuration information and receives data from the application.

Abstract: A method of workload scheduling in a distributed compute environment includes assigning a subscriber of a network service to a first compute node instance (“CNI”) of a plurality of CNIs within a network node interposed between the subscriber and a provider of the network service. The subscriber traffic associated with the subscriber is processed at the first CNI. Subscriber specific data is generated at the first CNI related to the subscriber traffic. The subscriber specific data is then backed up to a second CNI of the network node that is designated as a standby CNI that will process the subscriber traffic if the first CNI fails.

Abstract: Methods and systems are directed to dynamically mirroring a connection between network devices. Mirroring is managed by forwarding a packet between a first network device and a second network device. In one method, the first network device receives the packet from a client and communicates the packet to the second network device. A forwarding device, pre-determined from the first and second network devices, forwards the packet to a server. The first network device receives a response from the server, and communicates it to the second network device. The forwarding device forwards the response packet to the client. In one configuration, the first network device and forwarding device is an active device, and the second network device is a standby device. In another configuration, the first network device is a standby device, and the second network device and forwarding device is an active device.

Abstract: A method and an apparatus for rapidly resuming, at times of failures, network traffic in a connection-oriented network by using an alternative route pre-computed and stored locally in nodes along an initial route without requiring signaling of upstream nodes or a master server.

Abstract: A resilient interface architecture may include at least two interface switches and at least two interface routers. The at least two interface switches may provide connectivity between a subnetwork and a main network. if one of the switches fails, the connectivity otherwise provided by the failed interface switch may be provided by another one of the interface switches. Each interface router may be individually coupled to at least one interface switch. The interface routers may select a transmission path between the subnetwork and the main network through the interface switches. if one of the interface routers fails, the selection of transmission paths otherwise provided by the failed interface router may be provided by another one of the interface routers.

Abstract: An Ethernet-protection-switch system comprising a first transceiver node having Ethernet ports and transmit/receive lines communicatively coupled to a respective one of the Ethernet ports. The Ethernet ports include one active-receive Ethernet port and at least one backup-receive Ethernet port. Each transmit/receive line carrying duplicates of a data packet sent from a communicatively coupled second transceiver node. The duplicated data packet input from a transmit/receive line to the active-receive Ethernet port is received at the first transceiver node. The duplicated data packet input from a transmit/receive line to a respective one of the at least one backup-receive Ethernet port is discarded at the first transceiver node. If the transmit/receive line inputting the duplicated data packet to the active-receive Ethernet port fails, one of the at least one backup-receive Ethernet ports begins to function as the active-receive Ethernet port.

Abstract: A router for routing data redundantly relative to a network. The router includes a circuit card having a processor, a user port for connecting at least one user device with the processor, and a plurality of interface ports for redundantly connecting the processor with the network to provide active redundant communication with the user device(s). This router can have a small form factor, can be ruggedized, and can provide fast redundant routing through redundant network backbones.

Abstract: A computer implemented method, data processing system, and a computer program product are provided for processing packets in switches. A first switch receives a packet from a network that is to be directed to a host. A determination is made as to whether all of the ports connected from the first switch to the host have failed. If all of the ports from the first switch to the host have failed, the packet is sent through a backup port connected to a second switch, which sends the packet to the host.

Abstract: During normal operation, a user terminal supported by an IP-PBX server establishes a call by resolving the name of the IP-PBX server using a DNS server. When the DNS server provides the address of the IP-PBX server, the IP-PBX server can be contacted. However, if the SIP controller learns that the IP-PBX is no longer operating, the information stored by the service provider environment may be used to build or configure an IP-Centrex server at a remote site which takes over for the failing IP-PBX server. The newly configured IP-Centrex server then registers itself with the SIP controller and either the SIP controller or the IP-Centrex server then informs the DNS server of the IP address of the IP-Centrex and tells the DNS server that the IP-Centrex server will respond to messages for the failed IP-PBX server. The newly configured IP-Centrex server then handles the messages and control flow previously handled by the IP-PBX server.

Abstract: A telecommunication switch and an operating method for handling SDH signals transmitted by a protection SDH link associated to a working SDH link of an SDH hardware interface of the telecommunication switch. The telecommunication switch comprises a plurality of SDH hardware interfaces and an equipment protection arrangement. Each of the SDH hardware interfaces is connected to the equipment protection arrangement by a first and a second SDH connection. A protection SDH link of a first SDH hardware interface is connected to a second SDH hardware interface. The second SDH hardware interface is designed to forward protection SDH signals transmitted by the protection SDH link to the equipment protection arrangement using its first SDH connection. The equipment protection arrangement switches the protection SDH signals to a spare SDH termination module or an SDH termination module connected to the first SDH hardware interface according to a protection switching control signal.

Abstract: A data communication apparatus having a plurality of working ports for exchanging data traffic with a network element and at least one protection port. The communication apparatus also has a protection switching functional element to switch data traffic from a failed working port to the at least one protection port. The protection switching functional element is capable to acquire either one of a first mode of operation and a second mode of operation. The first mode of operation is an 1:Q mode using a single protection port where Q is the number of working ports and Q is equal or greater than 1. The second mode of operation is an M:N mode where M is the number of protection ports and N is the number of working ports, where M and N are greater than 1.

Abstract: A synchronous optical network (SONET) system having multi-hierarchal network service access point (NSAP) addressing includes a plurality of network elements (NEs) electrically linked, and a first level routing area and a second level routing area that each includes at least one NE. The NEs include devices having respective NSAP addresses and at least one of the NEs is a network controller that controls the SONET. The first level routing area and the second level routing area are based on a predetermined prioritization of the NEs as first level NEs and second level NEs, and have a first level routing and have a second level routing for the NSAP addresses, respectively, and each of the areas is capable of having at least 151 NEs.

Abstract: A method and apparatus are disclosed for monitoring and signaling a path restoration using pre-computed restoration paths following a detected fault on a primary service path in a communications network. A fault occurring inside the restorable portion of a network in heterogeneous or multiple network environments can be distinguished from faults occurring outside the restorable network in accordance with the ANSI Tandem Connection Maintenance standard, T1.105.05-1994. Path restoration is activated only when a fault causing path failure occurs inside the restorable portion of the network. Each conforming node in the restorable portion of the network has the necessary monitoring, signaling and cross-connect functionality and databases to participate actively in real time restoration. Additional non-conforming network elements can be positioned between the restoration nodes without preventing path restoration.

Abstract: Methods, systems, and devices are provided for controlling the power level of voice signal streams. One embodiment of a network device having router functionality includes a processor, memory in communication with the processor, and program instructions. The program instructions can be stored in memory and executable on the processor to designate a fail-over virtual router interface for a first physical router on a second physical router based on addressing information obtained via communication between the first physical router and the second physical router.

Abstract: Embodiments of the present invention provide for switchover from an active processor to a standby processor in a route processor system. An up-to-date copy of information used by a supervisor process at the active processor is ensured by determining necessary event states. One type of event state includes message requests, processing and replies. Three basic types of communication between three different entities (blade, wireless domain services (WDS) and supervisor) are governed by three types of communication protocols: WLCCP between a blade and WDS, LCP between a supervisor and a blade, and checkpoint-type messages between two supervisors.

Abstract: Methods, systems, and devices are provided for redundant router set up. One embodiment of a network device having router functionality includes a processor, memory in communication with the processor, and program instructions. The program instructions can be stored in memory and executable on the processor to designate a fail-over virtual router interface for a first physical router on a second physical router based on addressing information obtained via communication between the first physical router and the second physical router.

Abstract: A wireless network has nodes, which can be accessed by wireless terminals via wireless access links, coupled via wireless transit links using multiple directional antenna beams. The nodes are self-organizing and self-adapting as nodes are added and as other changes occur. A new node uses beam scanning to listen for signals from any existing nodes and responds accordingly to join a network. Established nodes each recurrently transmit a welcome message on unused beams, to be received by a new node. Failure of transit links, e.g. due to interference on a channel frequency, is detected with automatic restoration using another frequency. Beam scanning can be enhanced using alternate overlapping beams and diversity techniques.

Abstract: A method for routing a communication connection request includes the steps of obtaining context information from a communication connection requester in response to a communication connection request. The steps further include using the context information to determine a communication connection action, and connecting the communication connection requester based upon the connection action.

Abstract: A transmission apparatus including: a plurality of asynchronous network interface units each having an asynchronous network termination unit for inputting/outputting a packet from/to an asynchronous networks and a mapping unit for converting the packet into a first synchronous frame and vice versa, a plurality of synchronous network interface units each used for inputting/outputting a second synchronous frame from/to a synchronous networks, a buffer provided on at least a first of the asynchronous network interface units, and a control unit for storing a packet output by the asynchronous network termination unit for accommodating a specific asynchronous networks and a packet output by the asynchronous network termination unit of the first asynchronous network interface unit into the buffer by adding identifiers for identifying the asynchronous network termination units in the event of a line failure occurring in a synchronous networks on a route related to the specific asynchronous network.

Abstract: A communication system for a plurality of devices performing communications through a network is provided. The communication system includes a transmitter/receiver, a reception status detector, and a recorder. The transmitter/receiver is included in each of the plurality of devices and configured to alternately transmit a data packet with ID information indicating time to another device and receive the data packet from the device periodically in the plurality of devices. The reception status detector is included in each of the plurality of devices and configured to detect whether the data packet is periodically received based on the ID information added to the data packet received from another device. The recorder is configured to record a result detected by the reception status detector in each of the plurality of devices.

Abstract: A redundant network interface for ethernet devices is disclosed. The redundant network interface provides connections between one or more Ethernet devices and two or more independent networks. The redundant network interface device also tests an active primary Ethernet connection path, and when a failure or inactive path is detected, the redundant network interface device reroutes the messages to alternate communication path.

Abstract: A router in a survivable portion of a network may forward packets to a destination node even in the event of a double-link failure. For a given destination node, the router has previously been configured with a primary port, a primary backup port, and a secondary backup port. The router receives a packet addressed to the destination node within the survivable portion of the network, wherein the packet includes information indicating that the packet has encountered a failure. The router then selects one of (A) the primary port, (B) the primary backup port and (C) the secondary backup port on which to forward the received packet, such that a backup path with no dead loops is defined. The router may obtain a recovery distance of at least one of (A) the primary backup port based on a backup path to which it leads, and (B) the secondary backup port based on a backup path to which it leads, and may further obtain counter information in a packet indicative of a failure distance.

Abstract: A system comprises a plurality of processing modules, one of which is designated to be the primary processing module and the others are designated to be secondary processing modules. During operation, state is maintained in the primary processing module and at least one of the secondary processing modules. A switchover controller causes outputs from the secondary modules to be discarded. When the switchover controller receives an indication that the primary processing module has failed, it designates one of the secondary processing modules to be the primary processing module. Because the newly designated primary processing module already has current state information at switchover, the module is able to operate with minimal delay.

Abstract: A network element including an active/standby pair of line units, an active/standby pair of switch fabric units, at least one service unit, and a management and control unit. Each line unit maintains data communications using a first communications protocol. Each switch fabric unit maintains data communications using a second communications protocol. Each service unit includes a first backplane interface supporting the first communications protocol, and a second backplane interface supporting the second communications protocol. The management and control unit provides a control infrastructure for selectively communicating data units between the active/standby pair of line units, the active/standby pair of switch fabric units, and the service unit, responsive to provisioning information or information contained within the respective data unit.

Abstract: An active/standby switching system includes two AAL2 (ATM Adaptation Layer Type 2) cell assembling/disassembling processor units (20, 30) as an active system and a standby system so that active/standby switching is carried out between the active system and the standby system. The active/standby switching is carried out by transferring, from one of the AAL2 cell assembling/disassembling processor units (20) which has been the active system to the other AAL2 cell assembling/disassembling processor unit(30) which has been the standby system, handover information to prevent cell loss of AAL2 cells from occurring as a result of the active/standby switching and uncompleted cell data in the course of disassembling, the AAL2 cell assembling/disassembling processor unit (30) to become a new active system receiving the handover information and the uncompleted cell data and carrying out AAL2 cell assembling or disassembling.

Abstract: A method is disclosed that enables an improved technique for recovering from an error scenario encountered during a call setup that involves a malfunctioning media gateway and the corresponding media gateway controller. The media gateway first detects a malfunction that affects a digital signal processing resource. The media gateway then proactively selects a processing resource available elsewhere at the gateway. The media gateway selects the new processing resource based on criteria that include: i) the capabilities that were identified to handle the packet stream at the affected (faulty) processor; ii) the capabilities of the IP terminal originating the packet stream that is being moved; and iii) the Internet Protocol address of the affected processing resource. Advantageously, an effort is made to avoid having to inform the media gateway controller of the move, thereby minimizing any discontinuity in each packet stream and minimizing the time and processing that are required to establish the call.

Abstract: A modular cross connect system for optical telecommunication networks has the optical unit divided in at least two main bodies with one section for connection comprising the collimators and a main commutation section with MEMS devices. The first section is a fixed part while the second section is a readily removable section. The two sections face each other through a window and, in the first section, optics are provided for steering all or part of the optical signals from and to the main MEMS unit to a MEMS standby or protection plane to allow replacement of the main MEMS unit without interrupting service.

Abstract: A method for hitless restart of layer 3 packet forwarding includes replicating some but not all state information from a master management service module to a slave management service module. The master management service module builds a layer 3 routing table by participating in layer 3 routing protocols. The layer 3 routing table is stored in memory. The master management service module builds a first layer 3 forwarding table and stores the forwarding information in hardware. A slave management service module receives a copy of the first layer 3 forwarding table from the master management service module. When the master management service module fails, the slave management service module initiates construction of a routing table by participating in layer 3 routing protocols. Packet forwarding is not interrupted because forwarding using hardware entries continues. The slave management service module links entries in the newly constructed routing table to those stored in the forwarding table.

Abstract: A method for routing a communication connection request includes the steps of obtaining context information from a communication connection requestor in response to a communication connection request. The steps further include using the context information to determine a communication connection action, and connecting the communication connection requestor based upon the connection action.

Abstract: A system and method are disclosed for providing redundancy for telecommunication switches. A primary telecom switch has an active processing board and a passive I/O board for communicating with external sources, such as a control network and bearer traffic network. A redundant secondary telecom switch has an active processing board and a passive I/O board for communicating with a control network, and is connected to the I/O board of the primary switch through a redundancy connection for communicating with the bearer traffic network. According to the invention, the secondary telecom switch assumes the role of the primary telecom switch in the event that the primary processing board becomes unavailable. The secondary telecom switch then communicates with the bearer traffic network as the master switch through the redundancy connection and the I/O board of the primary switch, thus avoiding the necessity for reconnections and reconfiguration.

Abstract: A communication system utilizing an adjustable link has at least a first data transmission circuit including at least a first communication link circuit. The first communication link circuit has a baseband circuit and at least a passband circuit. The baseband circuit corresponds to a baseband sub-channel and the passband circuit corresponds to a passband sub-channel. The first communication link circuit also includes a circuit that distributes a first subset of a data stream having a first symbol rate to the baseband circuit and a second subset of the data stream having a second symbol rate to the passband circuit. The baseband sub-channel and the passband sub-channel are separated by an adjacent guardband of frequencies. The passband carrier frequency is adjusted to define the guardband and the guardband corresponds to a first notch in a channel response of a first communications channel.

Abstract: A communications system includes a base station that is configured to transmit a signal that is modulated according to a predetermined modulation scheme and an orthogonal frequency division multiplexing scheme, wherein the signal is encoded using space-frequency coding. The base station includes a plurality of multiple-input multiple-output (MIMO) transceivers. The system includes a terminal that is configured to receive the modulated signal. The above arrangement is particularly applicable to providing multichannel multipoint distribution services (MMDS) over a radio communications system.

Abstract: A method for data verification is provided. An input block of data is received together with a modulo-based input error detection code associated with the input block, the input block comprising a plurality of sub-blocks. A subset of the sub-blocks is selected to be included in an output block. An error correction term is determined based on the selected subset. The selected subset of the sub-blocks is concatenated together with the input error detection code and the error correction term to generate an output block for conveyance to a destination processor.

Abstract: The present invention provides redundant, inverse multiplexing over ATM (R-IMA). An ATM control system may include line interface circuitry, transmission convergence logic, IMA logic, and a cross-connect coupling the IMA logic of the redundant ATM control systems to control activity. The line interface circuitry terminates n DSx lines and is adapted to receive n incoming ATM over DSx traffic streams and transmit n outgoing ATM over DSx traffic streams corresponding to the n DSx lines. The transmission convergence logic is adapted to recover incoming ATM cell streams from the incoming ATM over DSx streams and generate the outgoing ATM over DSx traffic streams to form n outgoing ATM cell streams. The IMA logic is adapted to combine the incoming n ATM cell streams to form an incoming combined ATM cell stream, and distribute ATM cells from an outgoing combined ATM cell stream to create the n outgoing ATM cell streams.

Abstract: The present invention provides a communication network comprising a host network, a plurality of base stations, at least a mobile host capable of establishing links to the base stations, and a hierarchy-network of plural routers which are improved in transferring performances for ensuring continuous operations with a reduced load without packet loss.

Abstract: The present invention is directed to a method, a service node and a system for providing IP redundancy between a first service node and a second service node being mutually redundant. The first and the second service nodes are connected via a virtual connection. The first service node has a physical network interface to an IP node and a virtual network interface to the virtual connection. The first service node comprises a routing table having a cost associated with the virtual network interface. The method comprises steps of detecting by the first service node that the second service node is unavailable, updating in the routing table the cost from a higher value to a lower value and informing the IP node connected to the physical network interface of the update of the cost so as to process at the first service node traffic addressed to the second service node.

Abstract: A redundancy method in a network including an upper switch apparatus, middle switch apparatuses connected to the upper switch apparatuses via transmission lines and lower switch apparatuses each being connected to the middle switch apparatuses via transmission lines is provided. In the redundancy method, the upper switch apparatus has link aggregation setting for the transmission lines connected to the middle switch apparatuses, and each lower switch apparatus has link aggregation setting for the transmission lines connected to the middle switch apparatuses, and the upper switch apparatus and one of the lower switch apparatuses switches a traffic route from a transmission line that is failed and that is connected to one of the middle switches to another transmission line for which link aggregation is set with respect to the failed transmission line.

Abstract: A switching system for a data traffic network. A plurality of line cards provide input and output connections to a plurality of data lines and further are connected to at least two switch fabrics, one of which is designated the active switch fabric and the other designated the standby switch fabric. Data traffic is switched between the plurality of input and output line cards by the active switch fabric. When it is desired to change the active switch fabric assignment, for example due to a fault in the switch fabric, data transmissions into the active switch fabric are terminated and a drain timer is started. When the drain timer times out or the active switch provides an indication that it is empty, the active switch fabric assignment is swapped to the standby switch fabric and data is then switched through the newly assigned active switch fabric.

Abstract: A ring network having a plurality of nodes connected by a working channel and a protection channel. When no failure exists, the working channel and the protection channel are link-aggregated into one virtual channel, and the transmission of the working traffic is carried out using both channels. When failure occurred to a line of the network, the link aggregation is suspended and a protection function in conjunction with the link aggregation is activated, in which a path avoiding the failure point is established by means of layer 1 protection process and thereafter data transmission is carried out by use of the path established by the layer 1 protection function. Therefore, data transmission in the no failure stated can be conduced using a bandwidth of twice as large as that of convention ring networks.

Abstract: Recovery time upon the failure of a link or switching system in an asynchronous data network can be minimized if downstream data switches provide upstream messages indicating to upstream switching system that the downstream traffic arrived in tact and was properly handled. Upon this loss or failure of the upstream status message to an upstream switching system, an upstream switching system can reroute data traffic around a failed link or failed switch with a minimal amount of lost data. The upstream status message is conveyed from a downstream switching system to an upstream switching system via a reverse notification tree data pathway.

Abstract: A method is described that involves sending a positive imposter response as a consequence of a status request message having been received. The status request message refers to a network connection. The status request message was sent to the networking system to ask the networking system to inquire into the status of the network connection.

Abstract: In one embodiment, an intermediate node includes one or more active forwarding planes and one or more redundant forwarding planes. The intermediate node may also include one or more active control planes and one or more redundant control planes. A test packet is generated, in some cases by a redundant control plane, and transferred to a redundant forwarding plane. The operational state of the redundant forwarding plane is verified, at least in part, by using operational software and hardware contained in the redundant forwarding plane to forward the test packet from the redundant forwarding plane to a target line card. The target line card loops the test packet back to the redundant forwarding plane as part of the verification process. In some cases, the redundant control plane processes the looped-back test packet.

Abstract: A method for preventing information losses due to network node failure is disclosed. The method comprises the steps of operatively connecting at least one backup node to a primary node, followed by synchronizing the at least one backup node and the primary node. Next, the method comprises receiving, from a first endpoint, ingress traffic in the primary node and replicating the ingress traffic to the at least one backup node. Next, the method outputs, from the primary mode, primary egress traffic and outputs, from the at least one backup node, backup egress traffic. The method then determines if the primary node has failed. Then, the method transmits, to a second endpoint, the primary egress traffic if it is determined that the primary node has not failed, and transmits, to the second endpoint, the backup egress traffic from a selected one of the at least one backup nodes if it is determined that the primary node has failed.