Of network

A redundancy system for data communications upon two duplicate communication channels, each having transmission and reception circuits, characterized by a switching circuit for selecting one of said two communication channels, a single error detection circuit for detecting an error in the signal transmitted,...     

A microprogrammable data communications preprocessor exercises detailed control over a multiplicity of data lines communicating with a microprogrammable central processor while requiring central processor attention on a message basis only. Further minimization of central processor intervention is achieved...     

Primary and back-up closed loop unidirectional transmission lines transmit self-clocking data streams and null data, respectively, in opposite directions to a plurality of loop interface units (LIUs) connected to the primary and back-up lines. To protect against failure of the entire system due to a...     

A control system for use with a data transmission system having a plurality of subscriber stations connected exchangeably to a pair of transmission paths comprises a transmission control station provided for each of the transmission paths which produce an access signal to enable data transmission to...     

A system is provided for automatically bypassing an inoperative data terminal so that other data terminals connected in series therewith will continue to receive data transmitted from a central data processor. The system includes data terminal status indicators, a manual bypass capability, and a remote...     

A ring-configured network of multiple inter-communicating data stations in which each data station includes a fault sensing circuit, a test-pulse generating circuit and a switching circuit as well as a transmitter circuit and a receiver circuit, and the test pulse generating circuit responds to a sensed...     

A control system for controlling an industrial process includes a plurality of remotely located process control units (remotes) each coupled to an associated input/output device(s) and adapted to communicate with one another through a dual channel communications link. Each remote has a unique succession...     

A distributed, fault-tolerant, self-repairable, reconfigurable signal processing system with redundant elements comprising signal processors, mass memories and input-output controllers interconnected by redundant busses forming a high reliability system. The input-output controller element has redundant...     

A system using a sorting network to intercouple multiple processors so as to distribute priority messages to all processors is characterized by semaphore means accessible to both the local processors and the global resource via the network. Transaction numbers identifying tasks are employed in the messages,...     

A loop transmission system including a plurality of stations connected in series in a looped transmission line to transfer data among the stations, wherein the stations include a supervising station and at least one terminal station and the transmission line is duplicated so that when a fault occurs...     

A conference arrangement is disclosed having a plurality of logical multiport bridges for conferencing customer stations. Equipment units common to the bridges can be selectively connected to a station controlling each bridge. Upon the detection of a faulty unit, the interaction between the controlling...     

A ring communications system having a double ring format where the integrity of both rings is continuously checked, and where repair of the network is automatically accomplished upon the detection of the return to operation of a defective ring.

The present invention relates to an apparatus for verifying a data path through a digital switch between a transmitting port and a receiving port. The apparatus comprises a transmitter which transmits a test data block in a first predetermined time slot which corresponds to the time slot associated with...     

The present invention relates to a system for controlling multiple communications lines, so that a computer system can operate with a single component failure. Two processors are used to control two communications controllers and each of the controllers control up to 15 line controllers. Each line controller...     

A communications interface exchanges serial bit signals between sources differentially, over redundant, two conductor, primary and secondary channels. The primary channel provides the communications link during normal operation, and is monitored to ensure differential operation. In response to primary...     

A data transmission system comprising a plurality of reconfiguring devices (1-6) and a method of reconfiguring such devices. Each device (1-6) has a plurality of input and output data links (9-12), the devices being connected in a ring (18) whereby for each reconfiguring device data is received on one...     

A modular system for controlling the routing of data through a plurality of data terminals includes a number of modules in a tree structure. Each of the modules has circuitry for receiving a data stream. Each of the modules further has a plurality of ports, each port being suitable for transmitting data...     

A data transmission network has a plurality of modems to transmit and receive data and a nexus including at least two controllers to control the transmission of data between the modems. Each controller has input ports and output ports with each of the modems being connected to an input port and an output...     

A plurality of redundant channels in a system each contain a global image of all the configuration data bases in each of the channels in the system. Each global image is updated periodically from each of the other channels via cross channel data links. The global images of the local configuration data...     

A station diagnosis method in a communications network system including a closed ring transmission line and a plurality of data stations which can be connected to the ring transmission line by a plurality of line concentrators disposed in the ring transmission line wherein an internal ring transmission...     

A multiplex wiring system having a plurality of communication modules which are interconnected on a pair of buses. Data is transmitted from any one of the modules on one of the buses while redundant or complementary data is transmitted on the other bus. Each module includes three receiving channels,...     

A multiprocessor interrupt rerouting mechanism and method is disclosed for rerouting messages intended for a first processor to a second processor. In a fault tolerant computer system having several processors or LANs under the control of a single controller, when the controller completes a communication...     

When a trouble occurs on a transmission line, each station transmits a predetermined frame to the adjacent station. The station which does not receive the frame outputs to the adjacent downstream station a frame instructing that its primary output be looped back to its secondary input. The information...     

Control units are mutually connected by separate common signal lines. A data link is provided between the control units via a preselected one of the common signal lines. A check is made as to whether the preselected common signal line is operating normally or abnormally. When the preselected common signal...     

A communication data system is designed for resiliency by automatically replacing or bypassing defective units. The system includes a number of input/output terminals which are connected to MODEMs through a relay bank. The MODEMs send serial data to a serial I/O module which converts the serial data...     

A very useful data transmission system having a plurality of transmission modules connected to a single cable in a multidrop manner is disclosed herein. The system features its ability to check the transmission state at the level of individual modules through use of a proper code notation (typically,...     

There is provided a network monitoring system in which nodes are connected to the LAN as a communication medium using the token passing method and only the node to which the communication right was transferred can acquire the data communication right. The node has a communication right transfer instruction...     

This invention provides an improved means for communicating between a central communications or computer processor and a plurality of peripheral devices via a serial interface such as a pulse coded modulation (PCM) bus. The processor sends data via one of two redundant communications channels, such as...     

A method and apparatus for allowing a radio control console to failsoft to a predetermined channel assignment plan, without disrupting emergency calls then in progress, upon the failure of a CAD host computer link that would ordinarily provide control signals to the console. Channels are deassigned unless...     

A POS loop switching apparatus includes a switching circuit for selectively connecting first and second transmission lines, to which at least one Point Of Sales (POS) terminal is connected, and first and second file control means for periodically supplying a control signal, so as to constitute at least...     

In a ring network system including two transmission lines transmitting a signal in directions opposite to each other, and a plurality of line concentrators connected in the form of a loop by the two transmission lines and each accommodating a plurality of terminal stations connected to one of the two...     

A large number (e.g., 20 or more) independent processors are connected by a network that provides high data throughput (e.g., 64 megabits/second). The network has redundant data, arbitration, and status/control buses. The buses extend across a plurality of microstripline backplanes connected together...     

A method of operating a communication system which includes a number of host systems each communicating via sessions with other devices over different connections and in which the sessions assigned to a failed connection are suspended for a first and second time period and non-destructively moved to...     

A local area network is provided with increased tolerance to faults by arranging multiple hubs in nodes in the network. Internal connections in each hubs of the same node upon detection of a failure to provide an alternate path for data transmission in the network.

A system that guarantees reliable data transmission for one-to-many and/or many-to-many communications amongst data processing stations includes several dedicated functions/stations distributed across a communications network. One or more general participant stations connected to a shared communications...     

Workstations are connected via workstation controllers to two computer systems where one of the workstation controllers is a primary or controlling workstation controller and the other workstation controller is connected to appear to the primary workstation controller as a workstation and is designated...     

Rapid restoration of a telecommunication path between network nodes after an interrupting network link failure utilizes a distributed system of selective flooding for dynamically reconfiguring the internodal path in a manner which will ensure the most economical use of intermediate links. A help message...     

A fault tolerant interface station for processing and transmitting data, comprising first, second, third and fourth interface units. Each of the first and second interface units includes a receiver to receive input data, first and second memory sections, data lines to transmit data between the receiver...     

This system guarantees reliable data transmission for one-to-one, one-to-many and/or many-to-many communications among data processing stations over a communications network. A general solution is presented, and a new concept (the arbitrator node) is discussed in detail. Special logical nodes and a new...     

An automatic failure notification mechanism for use in a computer network wherein several co-operating parts of an application program are each running on a different node of the computer network. The mechanism comprises a set of linked subroutines called by each part of the application program and operating...     

A transmission failure diagnosis apparatus for use in a multiplex transmission system which sends and receives data by time division communication among a plurality of nodes connected by a common transmission path. This transmission failure diagnosis apparatus comprises a reception circuit, connected...     

An ATM communications system has two ring transmission lines in which network nodes are connected for transmission of cells in opposite directions. Each cell contains a first identifier identifying one of the rings and a second identifier identifying a path between source and destination nodes. Each...     

A self-repairing trellis network includes a plurality of stages (11, 12 and 13) wherein a first set of N processing elements and a second set of M processing elements are situated. The N processing elements are normally active while the M processing elements are designated as spares. The stages are connected...     

In a redundancy data transmission device in which a transmission signal is transmitted through all of a plurality of transmission lines constituting a redundancy transmission line and a receiving signal transmitted through any of the transmission line which is normal is selectively received, a check...     

A transmission system comprises nodes coupled in a ring via two multiplexed transmission paths having opposite transmission directions. The two paths can be time, space, or wavelength division multiplexed. Bidirectional communications between any two nodes are provided in normal operation using both...     

A known congestion avoidance system for computer networks detects congestion at a node output port if the average queue length (integral) over the last congestion cycle plus the current (incomplete) cycle exceeds a fixed constant (taken as 1). (A congestion cycle is a period for which the queue length...     

In a network system in which a line switching unit and the other line switching unit are connected with each other via communication lines and backup lines, and nodes which are connected with both the line switching units, respectively are adapted to communicate with each other via either one of the...     

A connector and data analyzer operate with a network of data storage devices connected to a serial data link. An arbitrarily large number of data storage devices may be connected via a serial data link with use of the connectors. Each device is connected to the serial data link by a connector. In one...     

A plurality of working synchronous terminal stations and one standby synchronous terminal station are housed separately and have different synchronous pulse sources. Each working synchronous terminal station receives and multiplexes STM-N signals using its own particular synchronous pulse source and...     

A system and method for a fault-tolerant system for parallel networks which interconnect processors and the first of the parallel networks distributed in an Omega configuration and the second of the parallel networks distributed in a reversed Omega configuration.

An optical bypass switch for a fiber optic local area communications network (LAN) with a ring topology allows an optical signal carried on the ring to by pass a node, which includes terminal equipment and a stub cable, associated with the switch. In a non-bypass mode, the optical signal is transmitted...     

A local area network uses standard ANSI FDDI LAN concentrator stations and a first set of mutually reverse-direction data buses or loops, in conjunction with an additional set of mutually reverse-direction data paths. The standard FDDI protocols when applied in the context of the particular connections...     

Pointer information that shows the bit time slot in a frame of low order group signals in which a leading location of substantial data of the low order group signals is placed, is utilised to provide a synchronous terminal station system of a 1:N redundancy configuration type having first to M-th main...     

A plurality of processors have a plurality pairs of input ports and output ports, and are constituted in a looped manner by connecting the output ports and the input ports of the same pairs of any number of processors. A transmission system is formed in which the data on the same loop is allowed to flow...     

A data exchange system for use in a system that includes a plurality of redundant channels (12). A data exchange unit (30) is provided to process data, ensuring that consistent data are used by each of the channels. The data exchange unit votes the data so that an output is provided that is identical...     

A network interface, in particular for motor vehicles having at least two computers and having at least two bus lines ("0") includes by a monitoring circuit (100), which cooperates with an evaluation circuit to detect the operativeness of the bus lines and identify a faulty bus line and an emergency...     

In a local area network system having redundant communication media and a plurality of nodes, each node is connected to the redundant communication media. Each node is capable of communicating with each other node in accordance with a predetermined protocol via the redundant communication media. Further,...     

A multiport access and reconfiguration unit for use in a dual token ring network is provided with three adapters and, depending on error conditions, can assume one of a plurality of recovery states in which a reconfigured single network is formed and at least one state in which an isolated single ring...     

A new event forwarding discriminator (EFD) EFD named the persistent/impervious event forwarding discriminator (PI EFD) is described herein. The PI EFD is monitored by the agent infrastructure in such a way that if the agent goes down, and thus the PI EFD goes down, the agent rebuilds or restores the...     

A communication line backup system provides a backup line for backing up a communication line which connects first and second subscriber terminals. The communication line backup system includes a first backup unit which is coupled to the first subscriber terminal, a second backup unit which is coupled...     

Disclosed is a new torus switch with low latency performance improves torus network connection time by trying multipaths in one single high speed operation. This multipath approach can be directed at establishing a connection between two specific nodes over various alternate routes simultaneously. If...     

Restoration of connections by a distributed restoration process in a fully or partly meshed communications network of nodes, the restoration method comprising the steps of responding at a first end node of a path in the network to receipt of an indication that the path has failed to retrieve the identity...     

A method for reducing the occurrence of a system-down phenomenon due to a communication clock trouble in a communication/exchange processing system, where possible, is described. In a communication/exchange processing system comprising a plurality of reference communication clock generators, a plurality...     

In a data processing system comprising a plurality of processing elements coupled to a network, a method of single-stepping the processing elements aids in debugging the system. Only one processing element at a time is permitted to execute N steps while its data output is coupled to the network. Once...     

A master/slave communication and control system includes a master controller and a plurality of slave subsystems, the master controller connected with the slave subsystems through first and second independent serial data buses, one of the data buses providing a working data bus, the other data bus providing...     

A so-called "softly broken apparatus" by constructing a self-repair apparatus based on functional redundancy. An apparatus is represented in a form including a function using an FBS diagram (a diagram comprising functions, behaviors and states). When a fault occurs, a function lost is retrieved by the...     

A failed network node is restored by specifying a number of facility transfer nodes and restoration nodes within any area of a network node, determining a given facility transfer node and a given restoration node to use in an area so that the total distance from each node in the area to the given facility...     

A system and protocol are provided for routing data packets from a host on a LAN through a virtual address belonging to a group of routers. The host is configured to point to the virtual address so that the packets it sends out of its LAN are always directed to a virtual router which may be any one of...     

A system for detecting and isolating faults in a two-wire communications loop which includes a number of node circuits dispersed along the loop. Each node circuit executes a fault detection algorithm and selectively switches its connections to adjacent node circuits to effectively isolate itself from...     

A fault-tolerant call-processing adjunct processor comprises a redundant, duplicated, service unit provisioning and maintenance processor), a duplicated LAN connected to both service units, and plurality of served units (voice-processing processors) each connected to both LANs. Each service unit and...     

A method is proposed for monitoring a computer network having at least two subscribers connected via a databus comprising at least two lines, said subscribers having in each case one receiving component and/or one transmitting component. The method is characterized by the fact that the functioning of...     

A digital signal transmission apparatus having a synchronous digital hierarchy interface having duplex channels is disclosed which prevents, when a code error occurs in a working channel, transmission of the signal including the code error to an apparatus connected at the next stage. The digital signal...     

An add-drop control apparatus includes first and second data input units for inputting external first and second data signals, respectively, a frame phase arrangement unit for arranging phases of an external add data signal, an add data controller for transferring a first add data signal from the frame...     

A fault-tolerant, fiber optic interconnect, or backplane, which serves as a via for data transfer between modules. Fault tolerance algorithms are embedded in the backplane by dividing the backplane into a read bus and a write bus and placing a redundancy management unit (RMU) between the read bus and...     

A distributed restoration process operated by nodes in a communications network, the process being run in a background mode, i.e. at times when a node is not operating at full capacity, the each end node of an existing path and having a higher network ID will act as master and broadcast path-finder signatures...     

The knowledge based system identifies the occurrence of a failure within the customer equipment and functions using its rules, hypotheses and collected data to isolate the functional resource which is the source of the error in the customer equipment and, whenever possible, "fence" or isolate the failed...     

A topology manager external to a communications network manages the network and in particular resolves conflicting topology information about the network by dividing the management of the topology data base into two operations--a collection instance and a resolution layer. A collection instance collects...     

A network interface is designed for two-wire reception via a serial bus and has a differential receiver which is connected to input lines. The network interface likewise has an element for recognizing error states on the bus lines. It is designed such that it changes into single-wire operation after...     

An Integrity Server computer for economically providing a stand-in computer, replacing a failed server of a network. The invention provides methods for re-establishing connections between clients and servers, and communicating packets between network nodes, to allow the Integrity Server to stand-in for...     

An interlocking apparatus capable of expanding a network while effectively using survivability of a self-healing ring, including a ring network connecting a plurality of nodes having a loop back function and a supplementary node connected to the first and second nodes of the ring netwrok. In the first...     

A distributed computing network has a packet routing system for routing packets among packet lists accessible to tasks. Packets are routed and attached to lists identified within a packet header or selected from router tables. Access to packet lists is managed according to data stored within packet list...     

The knowledge based system identifies the occurrence of a failure within the customer equipment and functions using its rules, hypotheses and collected data to isolate the functional resource which is the source of the error in the customer equipment and, whenever possible, "fence" or isolate the failed...     

A fault tolerant multiple network server system in which multiple servers concurrently act as back-up servers for each other even while they are providing their own server services to the system. Rather than having an unused server monitoring for failure of a primary server and taking over control, each...     

An ATM communication system including a plurality of communication nodes connected in a loop form by buses, buffers disposed in each communication node, a synchronizing pulse generation circuit for conducting cell demultiplexing of all communication nodes at the same timing, storage devices disposed...     

A manufacturing system is disclosed which includes first and second control devices as well as a communication terminal which controls communication with the control devices. The communications terminal includes an interceptor module which receives information from the manufacturing device and provides...     

A session recovery mechanism that permits the recovery of a session with a minimal delay to a user and with minimal data loss. When the client/server communications protocol process, such as TCP/IP process, issues an error message to a server and a client, the server and the client switch from a server...     

The main storage, the communication interface portion and the circuit control module hold transmission data in the buffers until completion of the transmission has been confirmed. When a fault has occurred in the current operating system of the duplexed portions in the configuration elements of the host...     

A multi-processor system has a plurality of processing elements interconnected by a network for transmitting data between the elements. Each of the elements has a status table, indicating that element's view of the statuses of all the elements in the system, and a reliability map, containing a bit for...     

A path switching system and method for a multiple-node ATM network, in which a plurality of paths can be simultaneously switched preserving proper correspondence thereof. A key choosing unit provided in a node chooses first and second sorting keys out of the virtual paths between the nodes, based on...     

A fault tolerant multiple network server system in which multiple servers concurrently act as back-up servers for each other even while they are providing their own server services to the system. Rather than having an unused server monitoring for failure of a primary server and taking over control, each...     

A method for providing fault tolerance in a client/server computer system. A client is initially connected to a primary server. The primary server normally handles all of the client's transactions. However, a secondary connection is designated to a backup server, whereby if the primary server ever becomes...     

A client server system has clients, a server of execution system, and a server of fault auxiliary system are connected. A process administrator is provided in each one of the server of execution system and the server of fault auxiliary system. When a fault has occurred in a disk processor in the server...     

An inter-equipment data link system performs a data link between double equipments of an A data transmission equipment and a B data transmission equipment. In the system, a monitor output of the A data transmission equipment is supplied to the B data transmission equipment. The monitor output of the...     

A recovery method and fail-over switch for use in a data storage system in which a plurality of data storage devices are connected to each of two communication paths. The switch may route requests to either of the two communication paths. Switching may be accomplished by two fail-over switches connected...     

A computer system comprises a system management subsystem and one or more operational subsystems, which are connected in a network, and the operational computer subsystem comprises notifying means for notifying management information relating to all resources under the management of a host computer to...     

A user definable set of event rollup relationships are maintained as a configuration element. Transitive closure of event rollup relationships is checked at the time of specification to detect cycles and prevent runtime errors. When an event to be processed is detected, the event is compared to defined...     

A network management device for managing a plurality of network elements has a network element management data acquisition unit for acquiring, in stages, various management data possessed by the network elements when a session with a network element is resumed and when the network management device itself...     

A network management system includes a main network management station and a backup network management station. Different physical and logic addresses are assigned to the two stations. The data packet(s) containing network management information has/have the physical and logical addresses assigned to...     

The inventive computer system uses a layer of software between the operating system and the hardware that localizes the fail-safe protocols into a single module. The system also uses shared memory allocation functions as the interface with the operating system. The memory allocation function creates...     

A method and system for entering the address of an address server to plural terminals connected to a switch, selecting a target address and switching to a substitute address server when a failure occurs in the target address server. In the invention when the switch is activated, its address management...