Abstract: A storage system having multiple I/O interface ports is configured to detect a failed communication condition at a port. The storage system is configured to then attempt communication using a port configuration of another port that also exhibits a failed communication condition. If communication is established, the port is reconfigured using the configuration of the other port.

Abstract: A duplexing control system and method of an ATM switching system capable of carrying out a stable switching of duplexing with a simple circuit construction is disclosed. The system has two boards respectively having a first interface matching with an input bus so as to interface received ATM cell, a second interface matching with an output bus so as to interface a transmitted ATM cell, an SAR for disassembling and assembling data units contained in an application layer in the transmitted/received ATM cell by a unit of ATM cell, a control section for controlling general operation in order to maintain the active state according to data processing information contained in a signal applied from the cell disassembling and assembling circuit, when the its own board is endowed with the active authority by the signal, and a DRAM for storing data transmitted/received for the switching of duplexing between the boards.

Abstract: A method for restoring a virtual path, provisioned between a source and a target node, in a zoned mesh optical network is described. The method, in one embodiment, allocates a primary and a secondary physical path to the virtual path. The two physical paths are network element and link disjoint. In case of a failure in one physical path, the end nodes switch the virtual path to the other physical path.

Abstract: An invention is provided for affording asynchronous fault-tolerant and adaptive communication in a distributed computing environment. The invention includes periodically updating a stored connection state value, which is received from an application. The connection state value indicates the number of data elements processed by the application. An interruption in a digital connection is then detected on a network between two endpoints. Upon detection, the stored connection state value is exchanged with the opposite endpoint over the network. In this manner, remaining data elements of the transaction can be received sequentially over the network from the opposite endpoint. In particular, the remaining data elements begin with a data element at a point indicated by the connection state value plus one.

Abstract: An optical network includes an optical ring and a plurality of add/drop nodes coupled to the optical ring. Each of the add/drop nodes is operable to passively add and drop one or more traffic streams to and from the optical ring, and each traffic stream comprises a channel. A hub node also coupled to the optical ring is operable to selectively pass and terminate individual traffic streams.

Abstract: A modular, reconfigurable, intelligent signal multiplexer for telecommunications purposes includes multiple feature cards. Each feature card contains an embedded microprocessor with associated RAM memory and flash ROM. The signal multiplexer processes digital inputs from a wide range of user equipment for transmission over digital facilities, including T1 and T3 lines. The system employs an Advanced Intelligent Multiplexer Network software package to perform network configuration and the establishment of maps. The maps including alternate maps, which in an embodiment include time-of-day-specific alternate routes. The functions of the signal multiplexers of a network are controlled by a mapping scheme. A map change alters the circuit-to-time slot assignments.

Abstract: A method for repairing a failed network connection between a client system and a network is disclosed. In a first aspect, the method preferably includes collecting real time connectivity information by the client system and utilizing the real time connectivity information by the client system to establish a connection with the network.

Abstract: A trunk in a network file server includes at least two communications ports. The trunk is created by combining the communications ports into a single virtual device and assigning ownership of the communications ports to the virtual device. A failsafe network device including at least two trunks, with each trunk coupled to different switches can be created by creating a third virtual device. Ownership of a first virtual device including communication ports coupled to a first switch and a second virtual device including communication ports coupled to a second switch is assigned to the third virtual device.

Abstract: In one embodiment, a network element is to be coupled to a first and second span of a number of spans that interconnect a set of network elements to form a ring network. In addition, each of the spans has two sub-spans on which traffic travels in opposite directions on a number of channels that circumvent the ring. Additionally, the channels on each sub-span include working channels and protecting channels. Furthermore, the network element includes a traffic handler to reprogram, responsive to protection switches and un-switches, the connection configuration on the protecting channels of the sub-spans of the first and second spans that provide traffic to the network element.

Abstract: A method and apparatus for managing signaling links in a signaling link set accommodates a plurality of signaling links having different data link formats in a signaling link set connecting adjacent signaling points. The method is preferably one which manages signaling links a signaling system No. 7 (SS7) network. This method includes adding one or more signaling links having different data link formats to a signaling link set of the SS7 network, and processing signal message transfer between adjacent signaling points through one or more main signaling links which have superior bandwidth compared with the added links. Through this method, it is possible to make a natural development of a signaling network possible, boost stability of signaling network by diversifying media for transfer simultaneously, and get economic effects in constructing a signaling network through re-using data links used previously.

Abstract: Restorable paths in an information network are established in response to arriving traffic requests. Requests are received at a first node of the network for transmission of traffic to a second node of the network, and each request specifies a desired transmission bandwidth for an active and a backup path to be established between the nodes. Potential active links for an active path are identified in response to a given request, and potential backup links to form a backup path for restoring the active path, are also identified in response to the given request. An active and a backup path are then formulated for each given request from among the potential active links and the potential backup links that were identified in response to the given request.

Abstract: Method, system, converter and switch for communication in asynchronous transmission mode (ATM) between a source end station (13) and a destination end station (14) by means of information cells and data cells following the information cells, the information cells representing a signalling message containing an information element (IE) which contains an indication of a requested kind of traffic contract (ATC) for, in accordance therewith, processing the data cells.

Abstract: A system and method for forwarding fault information in an optical network is disclosed. Responsive to a fault being detected at a node, the fault information is forwarded to the destination node in the form of a loss-of-signal condition by turning off laser transmitters used to propagate the signal towards its destination. Thus, a node or other network element not capable of generating an alarm signal consistent with an established alarm signaling protocol, such as a SONET alarm indication signal (AIS) or an SDH multiplexer section alarm indication signal MS-AIS, may still forward the fault condition to a downstream element.

Abstract: A system and method of controlling a bi-directional switching operation for a synchronous transfer mode (STM-1) signal transmission line of an asynchronous transfer mode (ATM) switch is disclosed. The system and method provide a rapid bi-directional switching operation through a 1+1 structure, being compatible with a 1+N structure, using MSP (Multiplex Section Protection) protocol. The process includes determining whether a signal fail has occurred, determining whether a priority of the signal fail is higher than that of a current signal fail determining whether a target station uses the same protocol as a source station if the priority of the signal fail is higher and performing a switching operation and transmitting a switching notification signal to the target station if the same protocol is used by the target station.

Abstract: A communication network includes first and second terminals, nodes, and links. The first node is coupled to the first terminal through the first link, and coupled to the second terminal through the second link and the second node. The first node preferably includes communication paths, each coupled to one corresponding first link and to the second link, through a multiplexing device, and routing signals between the links. The first node also preferably includes an alternate communication path coupled through the multiplexing device to the second link, a switch coupled to the alternate path, and a detector detecting failure of a communication path. A controller is responsive to the detector detecting a failure in a communication path and controls the switch to couple the alternate path to a corresponding first link, thereby enabling a signal to be routed between that first and second links through the alternate path.

Abstract: Communication is restored in a fiber optic network by placing error detection circuitry at the add/drop ports of the network nodes of the network. If the error detection circuitry detects an error condition for a communication signal traversing a normal communication path within the network, the communication signal is rerouted along a restoration communication path that is node and span disjoint from the first communication path. By requiring a restoration path to be node and span disjoint from the normal communication path, error detection circuitry need only be placed at the end nodes of the normal communication path. By allowing each node in the restoration path to dynamically choose the particular channels that can accommodate a particular communication signal at the time of the restoration, efficient use of available resources is gained. The result is a cost effective network that restores communication in times competitive to that of SONET rings.

Abstract: A method establishes two redundant Switched Virtual Channel (SVC) connections through ATM Networks using the same ATM End System Address (AESA) from a source ATM End Point to a destination ATM End Point. The method provides end-to-end path protection without relying on any underlying resiliency features of an ATM Network so that the set-up model is transparent to the underlying ATM Network.

Abstract: A cross point switch is configured to select from one of a first stream of ATM cells and a second stream of ATM cells, the first stream and the second stream being identical, and is further configured to select and substitute the second stream for the first stream upon detection of an error condition in the working circuitry operation on the first stream. The working circuitry, which is located on an interface module, is configured to receive and operate on the first stream of ATM cells. The protection circuitry, which is located on a redundant interface module, is configured to receive and operate on the second stream of cells. The protection circuitry and the working circuitry are functionally identical and synchronized to each other so that switching occurs from one stream to the other without interruption of network service.

Abstract: A header conversion device allowing reduced amount of hardware and memory and high-speed line switching is disclosed. In an ATM switching device having redundant incoming line systems, a header conversion table stores a set of header conversion information for one of the redundant incoming line systems. A header converter converts the header of an ATM cell received from each of the redundant incoming line systems by referring the same set of header conversion information.

Abstract: In order to avoid location of a buffer or a cache memory required for recovering a path trouble in the conventional storage unit, a new switch is provided between a computer and a storage unit. This switch manages a command to be relayed thereby, transmits to the computer an error response if the switch detects a trouble, and at a time changes a setting so that the subsequent commands may be transmitted through an alternate path.

Abstract: A scalable protection method for connection oriented networks includes a source, a destination, and primary nodes interconnected by working path segments between the source and destination. A point-to-multipoint connection with multiple destinations and additional primary nodes is also supported. Each of a number of backup nodes is interconnected with an associated primary node by pre-provisioned shunt segments, and the backup nodes are interconnected among themselves by pre-provisioned protection path segments. Upon occurrence of a failure, the primary node upstream of the failure directs input traffic to a shunt segment, and the backup node associated with the upstream primary node directs traffic from the shunt segment to an output protection segment. Downstream of the failure, a backup node directs traffic from an input protection segment to a shunt segment, and the primary node associated with the backup node directs the traffic from the shunt segment to a downstream working segment.

Abstract: An asynchronous transfer mode network, in accordance with the present invention, includes a plurality of remote terminals remotely disposed relative to a central office. The remote terminals are connected by a ring with two paths. The ring transfers signals thereon in opposite directions relative to each path. The central office feeds duplicate signals on each path. Each remote terminal includes a first multiplexer for routing signals transferred on the ring to and from an asynchronous feeder multiplexer. The asynchronous feeder multiplexer is adapted to route components of downstream signals on a first path of the ring to a destination and to replace the components of the signals on the first path with copies of components of signals running in an opposite direction on a second path of the ring such that at any location in the network both paths provide all signals.

Abstract: A system and method for fast and reliable failure notification and accelerated switchover for path protection in a communications network having several overlapping areas of nodes interconnected by communications links is described. Upon a failure event involving one of the communications links, a failure message is broadcast identifying the failed link, the broadcast being confined within the areas which include the failed link. A reliable transmission protocol is provided wherein at one or more of the nodes, a LAPD protocol unnumbered information frame containing the failure message is sent to connected nodes. The failure message is resent in another unnumbered information frame after a time interval unless an unnumbered acknowledgment frame containing or referencing the failure message is received from the connected node. A method of path protection includes establishing plural working paths through the nodes. For each working path, an associated protection path is precalculated.

Abstract: A network element maintains failure information for a packet-based network and usage information for a backup path. Upon receipt of a new demand, with an associated bandwidth, d, the network element determines if the backup path can be shared as a function of the failure information and the usage information associated with the backup path.

Abstract: A transmission apparatus includes a reception line selecting unit, a communication confirming frame transmitting unit, a communication confirming table, and a reception line deciding unit. The reception line selecting unit selects one of several reception lines each formed by the synchronous network. The frame transmitting unit transmits a communication confirming frame to the synchronous network at least at a predetermined period. The communication confirming table stores each reception time of the communication confirming frame received through the synchronous network. The deciding unit decides occurrence of failure on the reception line corresponding to the reception time when a difference between a reception time stored in the table and a present time at the predetermined period exceeds a predetermined value, and transmits instructions for switching the reception line to the reception line selecting unit.

Abstract: A crossbar switch system with redundancy has N+1 cross-bar switches. A first cross-bar switch has first outputs of each of a plurality of nodes applied to N input terminals thereof, an (N+1)th cross-bar switch has Nth outputs of each of the nodes applied to N input terminals thereof, and second to Nth (Ith) cross-bar switches each have first to Nth selection circuits, which are provided at respective input terminals thereof, to each of which are input mutually adjacent (I?1)th and Ith outputs among outputs of each of the nodes. Each (Jth) node has N selection switches, which are provided at input terminals thereof, to each of which are input Jth outputs of two mutually adjacent cross-bar switches among the first to (N+1)th cross-bar switches. In response to a selection control signal output from a failure processing circuit that executes crossbar switch failure processing, each of the selection circuits selects and outputs one of its two inputs.

Abstract: There is described a cross-connect apparatus which can apply a cross-connect operation in place of a function of a hard switch that has conventionally been used for a purpose other than a cross-connect operation, by selection of line setting information used for path switching and service selection operations, and by performing a cross-connect operation based on the information, thereby preventing redundant configuration of the cross-connect apparatus and diminishing power consumption.

Abstract: In a protection switching method for a passive optical network system, a communication abnormality is detected in at least one active-system virtual path established between an optical line terminal and a subscriber terminal through a transmission path and a network unit. When a communication abnormality is detected in an active-system virtual path, a switch is controlled to switch the transmission paths to establish a standby-system virtual path between the optical line terminal and the subscriber terminal as a communication partner. A protection switching apparatus for a passive optical network system is also disclosed.

Abstract: Methods and apparatus for automatically creating a path through a bi-directional line switched ring which uses common time slots are disclosed. According to one aspect of the present invention, an apparatus for creating a path between first and second nodes through a third node using first and second links includes a querying device, a comparator, and a routing device. The querying device identifies a first time slot of the first link for transferring data from the first node to the third node, and also identifies a second time slot associated with the second link for transferring data between the third node and the second node. The comparator determines when the first time slot and the second time slot are consistent, and the routing device computes the path between the first and second nodes using the first and second time slots when the first and second time slots are consistent.

Abstract: The present invention provides methods and systems for restoring communication in a fiber optic network by placing error detection circuitry at the add/drop ports of the network nodes of the network. If the error detection circuitry detects an error condition for a communication signal traversing a normal communication path within the network, the communication signal is rerouted along a restoration communication path that is node and span disjoint from the first communication path. By requiring a restoration path to be node and span disjoint from the normal communication path, error detection circuitry need only be placed at the end nodes of the normal communication path. By allowing each node in the restoration path to dynamically choose the particular channels that can accommodate a particular communication signal at the time of the restoration, efficient use of available resources is gained. The result is a cost effective network that restores communication in times competitive to that of SONET rings.

Abstract: The present invention supports a protection path in a radio access network in order to continue communication between terminating nodes of the radio access network if a failure occurs with a communications path between the terminating nodes. A node may assume the functionality of a router, a base transceiver station, or a base station gateway. The establishment of the protection path utilizes the redundancy of connectivity in the radio access network when routing the protection path in accordance with a service protection model. The protection path may be configured with a service protection model that is based on a quality of service model or on a separate protection model. With a quality of service being associated with a traffic class, the service profile indicates the quality of service for different types of services for a user as well as the quality of service that is provided by the protection path if a failure occurs with the communications path.

Abstract: There is disclosed a communication system in which a line switch signal is sent to a remote station side from a local station side to switch a line without deteriorating the transmission efficiency. A CC message encoder allots the unused bit of CC message to a line switch signal for requesting line switch to a line switch circuit. DCME inserts CC message into a predetermined position in a DCME frame during a multiplex processing. DCME extracts CC message from the received DCME frame. A CC message decoder extracts the line switch signal included in the CC message. The line switch circuit connects one of a plurality of lines in response to the line switch signal.

Abstract: A path network and a path network operation method capable of dealing with an abrupt traffic variation by realizing fast path bandwidth increase are disclosed. A path network is operated by transmitting path signals from a transmitting node to a receiving node through the working paths and the protection paths, and converting a protection path into a working path temporarily in order to increase a bandwidth of the working paths when a bandwidth increase request occurs in the path network. The transmitting node and the receiving node can convert a protection path into a working path by using the automatic path conversion information contained in the path overhead attached to the path signals.

Abstract: In a multiprocessor computer system with multiple nodes, a static end to end retry apparatus and method uses the concept of sequence numbers combined with a path number. All transactions sent along a path are delivered in order to remove any time dependency. The apparatus and method ensure there are no duplicate transactions through the use of special probe and plunge transactions and their respective responses. The apparatus and method also allow for any number of alternate paths being active simultaneously, such that if one path fails, the remaining alternate paths can continue on the communication (along with the backup alternate path if desired) as usual without any loss of transactions. Each node keeps track of transactions the node has sent over time to every other node, as well as every transaction the node has received from every other node along each active path for each flow control class. To accomplish this tracking function, two data structures exist.

Abstract: A WDM ring network and method for distributing within such ring network for feeding in data and for distributing both working signals and protection signals on different transmission paths and in oppositely directed transmission directions, and for forwarding data from subscribers and for distributing the working signals to the subscribers.

Abstract: A switching system. The switching system includes a first switch having a primary receive port and a secondary receive port. The switching system includes a second switch connected to the first switch. The second switch has n receive ports, where n is greater than or equal to 2 and is an integer. The second switch has m transmit ports, where m is greater than or equal to 2 and is an integer. The transmit ports are decoupled from the receive ports. The second switch has a connecting mechanism that includes a multicast mechanism which sends data out a primary transmit port of the m transmit ports to the primary receive port of the first switch to define a primary path, and out a secondary transmit port of the m transmit ports to a secondary receive port of the first switch to define a redundant path to the primary path so that if there is a failure of the primary path to provide the data to the first switch, the data is received by the first switch through the redundant path.

Abstract: A path reroute mechanism for use in communication networks comprising multiple searches for a routing path to restore traffic following a failure that could not be protected by a previously established protection route (i.e. protection tunnel, bypass, etc.) or for routing or rerouting of traffic paths for optimization or any other purpose. Each node advertises TLVs that include bandwidth allocation information used to derive the actual amount of bandwidth available for protection purposes, protected paths and unprotected paths or a portion of this information such as in the case where unprotected paths are not supported. Searches are performed on larger and larger portions of the available bandwidth until a route for the path is found.

Abstract: In a node device having a function of recognizing route information of a network, a route selector selects a connection setting route based on the dynamic route information of the network, and generates a reservation request of a predetermined optimum route unless the connection setting route is the predetermined optimum route, a route switchover reservation portion monitors whether or not the predetermined optimum route becomes available based on the route information during the communication, and makes switchover instructions toward the predetermined optimum route to a call processor. The call processor sets a connection in a selected connection setting route, and sets another connection in the predetermined optimum route by the switchover instructions.

Abstract: The invention provides for a method for transporting a SONET formatted asynchronous transfer mode (ATM) signal and/or a synchronous transfer mode (STM) signal on a line switched ring over a unidirectional path. The SONET formatted ATM signal comprises cells mapped into a STS-Mc or m×STS-1s while the STM signal comprises STS-1s/VTS mapped STS-W. A unidirectional line switched ring is provided for transporting the STM STS-W using a unidirectional path switched protection protocol and the ATM STS-Mc using a unidirectional line switched protection protocol. A ring node comprises input and output ring interfaces, an STS management block, an ATM cell management block, and a non-ATM payload management block. The STS management block routes the traffic to the ATM cell management block and to the non-ATM payload management block, according to the traffic type. The STS management block also provides the UPSR protection for the STS-1s and ULSR protection for the STS-Mc.

Abstract: Embodiments are described to provide automatic failover in a channel-based network. According to an example embodiment, a virtual port to physical port mapper is provided.

Abstract: Telecommunications Network In a telecommunications network, a level of redundancy is often provided so that in the event of a circuit failure a back-up route may be used. A telecommunications network in which automatic switching of telecommunications traffic to back-up circuits is disclosed herein when faults are detected on a traffic carrying circuit. In particular, when dedicated private circuits develop faults, a network automatically switches traffic to a dedicated back-up circuit. Particular points on incoming and outgoing circuits of a switch are monitored. Faults at particular points result in autonomous switching of traffic to a dedicated back-up circuit. Communication is facilitated between switches by using predetermined signals on the dedicated back-up circuit.

Abstract: Router line cards are partitioned, separating packet forwarding from external or internal interfaces and enabling multiple line cards to access any set of external or internal data paths. Any failed working line card can be switchably replaced by another line card. In particular, a serial bus structure on the interface side interconnects any interface port within a protection group with a protect line card for that group. Incremental capacity allows the protect line card to perform packet forward functions. Logical mapping of line card addressing and identification provides locally managed protection switching of a line card that is transparent to other router line cards and to all peer routers. One-for-N protection ratios, where N is some integer greater than two, can be achieved economically, yet provide sufficient capacity with acceptable protection switch time under 100 milliseconds.

Abstract: A decision engine decides whether to assign a service line to be active or in standby mode with a very simple decision logic that is based on a comparison between two numbers that are created through the setting of bits in two registers. The logic of the decision engine is embedded in a combination of a filter that either accepts or rejected applied stimuli, and a table that acts on accepted stimuli by the setting and resetting of bits in the two registers in accordance with a unique specification.

Abstract: A method for standby switching in optical transmission devices is provided, wherein, in addition to a working signal and a protection signal, respective control signals with information concerning the allocation state are transmitted and evaluated at the receiving end. The control signals are transmitted via a monitoring channel even when the useful signal is switched off.

Abstract: A method of rerouting a digital intra-office signal through a telephone central office comprises the steps of retrieving identification data for ports of first and second digital access and cross-connect systems, the ports being connected by an intra-office digital trunk, retrieving identification data for an alternative path from the first cross-connect system to the second cross-connect system, correlating identification data for the alternative path to the identification data for the intra-office digital trunk, determining availability of and displaying alternative path data responsive to entry of identification data for the intra-office digital trunk, and rerouting the intra-office digital signal via the alternative path.

Abstract: A system and method for implementing a shared protection scheme under a scenario of multiple failures in an optical network. In one embodiment of the invention, a working path between an ingress node and an egress node is computed responsive to a connection request received in the network. One or more backup paths are computed between the ingress and egress nodes, which are activatable upon a failure condition associated with the working path or the backup paths. The backup paths may be based on link and/or node disjointedness, as well as resource-based cost constraints.

Abstract: A transmitter capable of retransmitting an MPEG2-TS packet up to the reconstruction time limit and a receiver capable of requesting a retransmission of the packet up to the reconstruction time limit are provided by effectively using a waiting time of a packet to be reconstructed. The transmitting apparatus is provided with a timer portion 13 that shows a current time T in a wireless transmission, a time stamp adding portion 17 that adds a time stamp for specifying a time TS(N) for the packet N to be processed at a receiver side to the packet N, and a calculation portion 14 that calculates a packet transmission required time T_P during which the packet N is transmitted from a transmitter side and then received at the receiver side. In a case where a retransmission request of the packet N from the receiver side is issued, the time limit TL for the retransmitted packet to be received in time for the processing at the receiver side is calculated by the equation of TL(N)=TS(N)−T_P.

Abstract: Method and system for the management of a V5 interface in a telecommunication system comprising a first network element, a second network element, which is connected via a V5 interface to the first network element, and a management interface connected to different network elements. Link identification is performed on the basis of a standard request issued from a network element. According to the invention, when link identification is requested via the management interface and when link identification cannot be started in the network element through whose management interface the link identification request is issued, a notice of failure of link identification is given locally to the management interface.

Abstract: Method and system for shared path protection within an optical ring network wherein the network includes a plurality of nodes. A traffic signal is forwarded on a working path on a wavelength. The working path includes a drop node. The traffic signal is individually monitored the traffic signal on the wavelength at the drop node for a failure. In response to at least a detection at the drop node of the failure, a protection switching request is generated. In response to at least the protection switching request, the network is provisioned to forward the traffic signal on the wavelength on a protection path to the drop node.

Abstract: A DCME system having a circuit switching capability for use in a redundant communication system is disclosed. Alarm conditions defined in ITU-T Recommendations G.732 and G.763 are previously stored. When detecting alarm information defined in ITU-T Recommendations G.732 and G.763 from a received signal on each radio circuit, it is determined whether a failure has occurred on each radio circuit by comparing the alarm conditions with the alarm information. One of the radio circuits is selected based on the determination results.