Abstract: The present invention relates to the networking of a large number of endpoints using a high bandwidth optical backbone. The large number of endpoints, which may be thousands or more in number, connect through a local access telecommunications networks to points of presence. From each point of presence, the connection with the endpoints are routed directly to an optical node, which provides access to and from the high bandwidth optical backbone. No intermediate network layer is employed between the point of presence and the optical node, thereby reducing network complexity, increasing network stability, and eliminating limitations on bandwidth available to the endpoints imposed by an intermediate network layer and communications protocols employed therein.

Abstract: An apparatus and method are disclosed for rebuilding a data storage array having plural communication paths. A first error detecting component detects an error at a data storage device of a data storage array. The data storage device has a plurality of ports and is operable to provide data for a preemptive rebuild. A port control component disables all but a single port of the data storage device. A preemptive rebuild component copies data from the data storage device to a spare data storage device using the single operational port. An alternative path maintenance component maintains an alternative communication path for use by other members of the data storage array and bypasses the data storage device. A second error detecting component detects an error at the data storage device during operation of the preemptive rebuild component. A device disabling component disables the data storage device after detecting a second error.

Abstract: A method for communication is used in a communication network that includes multiple ring nodes arranged in at least first and second ring networks, which are connected by one or more of the ring nodes serving as interconnect nodes. A data packet is accepted from a source user node served by the first ring network, for forwarding to a destination user node served by the second ring network. An identifier, which identifies an interconnect node in the first ring network through which the data packet is to be forwarded to the second ring network, is attached to the data packet in the first ring network. The data packet is forwarded over the first ring network, accepted at the interconnect node and, responsively to the identifier, forwarded from the interconnect node to the second ring network. The data packet is forwarded over the second ring network to the destination user node.

Abstract: Multi-Protocol Label Switched (MPLS) traffic is re-routed to an alternate, Label Switched Path (LSP) to bypass a failure along a primary LSP, even though the failure occurs at or along an ingress section of an LSP, while associating an original IP address to the alternate path. Failures are also detected farther downstream outside an ingress section. When this occurs, MPLS traffic is re-routed to an alternate LSP which maintains the same quality of service as an original primary path and includes other network devices which are not a part of the primary path (except for the network device and a destination network device). The techniques require less resources than existing techniques.

Abstract: A transmission device, which carries out a route control of a frame based on a label included in the frame in a ring network, includes: a generating unit that generates a message for collecting information on first/second labels allocatable to working/standby routes; a transmitting unit that transmits the message in the ring network; a receiving unit that receives the message after being circulated in the ring network; and a selecting unit that selects one of the first/second labels for the working/standby route based on the information included in the message.

Abstract: Packet-aware transport architecture and techniques for implementing same that enhance data volume by scaling effectively to rapid data growth are disclosed. For example, a technique for determining a route for a demand in a circuit-switched network comprises the following steps/operations. The demand to be routed in the circuit-switched network is obtained. The circuit-switched networks implements a packet ring (PR) model such that one or more demands are routable on one or more virtual data rings in the circuit-switched network. An Ethernet-Over-SONET (EOS) communication channel in the circuit-switched network suitable for accommodating the demand is specified. The EOS communication channel or one of the one or more virtual data rings is then identified as the new route for the demand.

Abstract: In one embodiment, a network comprises a plurality of nodes that are communicatively coupled to one another using bidirectional, half-duplex links. The network has a logical first channel over which data is propagated along the network in a first direction and a logical second channel over which data is propagated along the network in a second direction. For a given period of time, at least one of the plurality of nodes is scheduled to be a transmitting node that transmits data on both the first channel and the second channel. A first subset of the nodes not scheduled to transmit during the period are scheduled to relay data received from the first channel along the first channel. A second subset of the nodes not scheduled to transmit during the period are scheduled to relay data received from the second channel along the second channel.

Abstract: A communications network (100) includes at least one control station (160) and a group of network nodes (110, 120, 140). The at least one control station (160) generates batches of forwarding tables (300), where each batch of forwarding tables (300) includes a primary forwarding table (305) and a group of backup forwarding tables (310), and forwards the batches of forwarding tables (300). Each of the network nodes (110, 120, 140) is associated with one or more outbound and inbound links and is configured to receive a batch of forwarding tables (300) from the at least one control station (160) and install the primary forwarding table (305) from the batch (300) as a current forwarding table.

Abstract: Methods and apparatus for switching Fibre Channel Arbitrated Loop Systems is provided between a plurality of Fibre Channel Loop devices. In one aspect of the invention, the system switches based at least in part on arbitrated loop primitives. An exemplary interconnect system may include a first port and a second port, both including port logic to monitor certain arbitrated loop primitives, a connectivity apparatus, a route determination apparatus including a routing table consisting of ALPA addresses and their associated ports, the route determination apparatus coupled to each port and the connectivity apparatus, where the connectivity apparatus creates paths between the ports based on arbitrated loop primitives. In one embodiment, the connectivity apparatus is a crossbar switch. Examples of the arbitrated loop primitives that cause the switch to create paths between ports includes one or more of the following: ARB, OPN and CLS.

Abstract: A method for a communications network with a protect channel transmitting protect channel data and working channel transmitting working channel data includes transmitting the working channel data via the protect channel upon a disruption in the working channel, and restoring the transmitting of protect channel data, wherein the restoring includes applying a mesh restoration protocol to the communications network to restore the transmittal of the protect channel data. The restoring includes finding one or more alternate channels to transmit the protect channel data, the one or more alternate channels including connected working and protect channels.

Abstract: A switching unit (1011) receives video data (103) sent from a device (102), and sends an ATM cell synchronized with the clock to switching units (1012-1014) by a signal (including optical data) containing a frequency component serving as a synchronous clock supply source. If a fault occurs midway along a line, the switching unit (1012) which detects the fault sends an AIS cell to an OAM connection (109). The termination switching unit (1014) switches a port f for receiving a synchronous clock to a port g, and sends back an RDI cell. The switching units (1013, 1012) which have received the RDI cell switch the synchronous clock to ports e and c and receive it, thus obtaining an identical clock.

Abstract: A method of ring network protection is provided. A node in a ring network determines a section that suffers a fault and determines a timeslot of a service impacted by the fault on the node according to section ring formation information and service route information preconfigured on the node when trigger conditions of protection switching are fulfilled, and switches the service onto a protection channel that bypasses the section that suffers the fault, where: the section ring formation information lists the information about the sections included in a ring consecutively in a preset direction; and the information about the sections includes preassigned IDs of sections between adjacent nodes in the ring network; and the service route information lists the information about the trails that use the node as a source node and a sink node of the service in each specific timeslot. A network element device is also provided.

Abstract: A link state machine for the Advanced Switching (AS) Architecture includes added transition sub-states. Transition events typically handled in AS link states are handled in the transition sub-states. Separating the transition events and flow from the link states into smaller transition sub-states may make the AS link machine easier to manage and facilitate debugging efforts.

Abstract: A building control or danger warning system includes a two-core circular bus for voltage supply and for communication with bus user circuits connected to the cores of the circular bus. The bus user circuits are looped-into the circular bus via FET (field effect transistor) polarity-reversal protection bridges, thereby simplifying connection of the bus user circuits to the circular bus. A bus user circuit is located between d.c. connection terminals and connected in parallel with two protection bridges. The bus user circuit measures the voltage conditions and polarity of the a.c. voltage input terminals of the bridges. According to the results of the measurement, the bus is relayed to the subsequent bus user circuit.

Abstract: In a method for enabling facilitation of re-convergence, designation information for a first port of each one of a plurality of bridges in a multi-bridge ring is received and designation information for a second port of each one of a plurality of bridges in a multi-bridge ring is received. The first port of each one of a plurality of bridges is a first direction Ring Rapid Spanning Tree Protocol (RRSTP) port and the second port of each one of a plurality of bridges is a second direction RRSTP port. The first direction around the ring (e.g., a forward direction) is opposite the second direction around said ring (e.g., a backward direction). A first reserved RRSTP MAC address is associated with the first direction port of each one of the bridges and a second reserved MAC address is associated with the second direction port of each one of the bridges.

Abstract: A method and a device of network protection are disclosed to protect transmission of the PBT service when a link or node fails in the PBT network. The method comprises: switching a Provider Backbone Transport (PBT) service impacted by a fault to a protection Provider Backbone Bridge (PBB) service according to a preconfigured corresponding relationship between the PBT service and the protection PBB service when a working link or a working node fails in a ring network; and forwarding a service frame of the protection PBB service in a PBB service forwarding mode. A network device for implementing such a method is also disclosed. The technical solution under the present disclosure enables simultaneous transmission of both the PBT service and the PBB service in the same network, requires use of only one protection technology, and draws upon the traditional Ethernet protection technology to protect the PBT service.

Abstract: A node in a first ring stores therein connection information about connecting nodes between a second ring and a third ring. Upon receiving a route of a working path by a signaling, the node determines any one of nodes composing the second ring as a branch node. If the working path is not terminated on an end node that the working path ends in the second ring thereon, and also if no node composing the second ring stores therein connection information between the end node and any one of the connecting nodes in the third ring that is connected to the second ring, the node compares each condition of selectable routes of a backup path between the end node and the branch node, and selects any one of the selectable routes as the backup path based on a result of comparison.

Abstract: A network element receives frames from multiple ring networks. Each ring network linked to the network element is supported by a designated support program. The received frames are monitored for conditions indicative of a failure in one of the ring networks. Upon detection of a failure condition, the designated support program for the failing ring network is determined and notified. The designated support program then addresses the failure condition by, for example, switching to a backup link. In one example, the multiple ring networks are SONET BLSR networks.

Abstract: A virtual ring representing a community of interest is constructed from an interconnected mesh of nodes in a packet network. The virtual ring instantiates ring labels in respective forwarding tables for each node in the virtual ring and then advertises the ring labels to all other nodes in the virtual ring, for example by flooding BGP advertisements. Data packets entering the ring are assigned a ring label which is then stripped off when exiting the ring. The data packets are forwarded around the virtual ring using the ring labels. The virtual ring can operate using BGP/LDP Multi Protocol Label Switching (MPLS). Multiple virtual rings can be bridged together using a central hub or alternatively multiple virtual rings can be redundantly bridged together using tandem hubs.

Abstract: A communications system provides for secure communications of information over multiple communications links. The system includes a client device, a server device, and at least one, and typically multiple, available and usable communications channels, elements, modes and links for connecting the devices for communications of information therebetween. The system includes a link detector for determining existence and usability of the communications links for communications of the information, a pathfinder for selecting one or more of the communications links for communications of at least some of the information, a link handover for switching to the selected one or more communications links for communications of the information or portion thereof, and an auto reconnector for re-connecting to detected and selected one or more communications links for communications of the information or portions of it in the event that any communication is hindered, terminated or upset.

Abstract: An object is to provide a redundant supervisory control system and a redundancy switching method thereof. In the redundant supervisory control system, remote I/O apparatuses are less likely to be inaccessible, even in a case where failures occur in plural locations. Thus, the reliability of the system is enhanced. The redundant supervisory control system including a plurality of first loop interface units in each of a pair of controllers, second loop interface units, and communication cables each connecting the plurality of first and second loop interface units with one another in a circular loop. The redundant supervisory control system is configured by connecting the controllers and the remote I/O units to one another in a plurality of loop networks. In a case where abnormality in the loop networks is detected by use of received data in the networks, the first and second loop interface units that can perform normal reception are automatically selected.

Abstract: A communication network has an open-ended communication loop coupled to a communication ring at separate points on the ring. The communication network has wireless access points that are coupled to the loop. The wireless access points exchange user communications in a wireless communication format with user wireless communication devices. The wireless access points exchange the user communications with a service center over the communication loop and the communication ring. The wireless access points re-route the user communications to avoid a fault on the loop.

Abstract: Disclosed is a ring network in which ring domains are managed in ring forms, layer 2 switches located on both ends of a link shared by a plurality of the ring domains monitor the shared link, and one of the ring domains that share the shared link expands to another ring domain when a failure is detected in the shared link. The locations of blocking ports are managed by an initially configured master node in each ring domain, and the locations of the blocking ports remain unchanged when the ring domain is expanded.

Abstract: A method and apparatus for mesh based protection of an optical network is described. A method comprises protecting a first set of one or more optical sub-channels with automatic protection switching, utilizing a second and third set of one or more optical sub-channels to transmit traffic in accordance with a mesh process to transmit traffic, and transmitting traffic in the third set of optical sub-channels, which would have been transmitted in the second set of optical sub-channels, in accordance with routes determined by the mesh process in response to an alarm indicating a failure affecting the second set of optical sub-channels.

Abstract: A topological information management frame is classified based on the contents stored in the topological information management frame, and information stored in a database is updated based on the contents stored in the topological information management frame depending on the classification of the topological information management frame.

Abstract: In a method for enabling facilitation of re-convergence, designation information for a first port of each one of a plurality of bridges in a multi-bridge ring is received and designation information for a second port of each one of a plurality of bridges in a multi-bridge ring is received. The first port of each one of a plurality of bridges is a first direction Ring Rapid Spanning Tree Protocol (RRSTP) port and the second port of each one of a plurality of bridges is a second direction RRSTP port. The first direction around the ring (e.g., a forward direction) is opposite the second direction around said ring (e.g., a backward direction). A first reserved MAC address is associated with the first direction port of each one of the bridges and a second reserved MAC address is associated with the second direction port of each one of the bridges.

Abstract: The disclosed network includes two rings, wherein a first ring transmits data in a clockwise direction, and the other ring transmits data in a counterclockwise direction. The traffic is removed from the ring by the destination node. During normal operations (i.e., all spans operational), data between nodes can flow on either ring. Thus, both rings are fully utilized during normal operations. The nodes periodically test the bit error rate of the links (or the error rate is constantly calculated) to detect a fault in one of the links. The detection of such a fault sends a broadcast signal to all nodes to reconfigure a routing table within the node so as to identify the optimum routing of source traffic to the destination node after the fault.

Abstract: Methods and apparatus for enabling line-protected links to be included in path-protected segments of a unidirectional path-switched ring are disclosed. According to one aspect of the present invention, a method for computing a circuit path that includes a primary path between a start node and a destination node as well as an alternate path includes determining the primary path using a routing algorithm. The primary path includes a protectable segment which has a first line-protected link. The method also includes creating the alternate path using the routing algorithm. Creating the alternate path includes creating the alternate path between the start node and the end node with the alternate path arranged to protect at least the protectable segment which includes the first line-protected link. In one embodiment, the alternate path is created including the first line-protected link.

Abstract: A method (600,700) and apparatus (800) are arranged and operate for facilitating call routing between sites in an enterprise connected by a private IP network (130). A range of identifiers (220-223) served by IP PBXs (120-123) in the enterprise may be registered with a SIP registrar (212) of an inter-site router (210). Call requests to a communication unit (350) outside the home site are routed to the SIP registrar. A site identifier associated with the destination IP PBX allows the call to be completed by the SIP Proxy or the IP PBX where the call was received. When no private IP network is available, a roaming CU registers with a cellular proxy in the visited network. Calls are routed by when an HLR (340) associated with the CU obtains the roaming number from the cellular proxy (330) in the visited site. The MSC completes the call to the visited IP PBX using the roaming number and a local SIP registrar 440 forwards the call to the CU.

Abstract: Sets of communication modules each have a pair of ring-channel ports for a ring-configured channel in a network, a peripheral device port for peripheral device data, and dual-ring ports for an inter-ring channel for the pair of modules. First and second ones of a set of communication modules send duplicate data packets on their respective first and second rings. Responsive to duplicate data packets arriving via the rings at first and second modules in a next set within a predetermined time interval of one another, each of the next modules transmits its ring-channel received data packet out a downstream ring-channel port. Responsive to one of the duplicate packets arriving at the DRP of a module a predetermined time interval before arriving at a ring-channel port of the module, the module sends the corresponding packet received at the DRP out its other ring-channel port and its peripheral device port.

Abstract: A layer three enabled layer two network includes a multi service platform. The platform includes a layer two switching component and a layer three switching component and has a physical loopback connected between the layer two switching component and the layer three switching component. The layer two switching component is a terminating point for connections of the layer two network, enabling end-to-end layer two connections. The physical loopback enables the layer three features while increasing reliability of end-to-end connections across the network, and simplifying provisioning of layer three enabled layer two networks.

Abstract: A system and method are described herein that are capable of reducing overhead while keeping the traffic separation characteristics between two routers by establishing and using a generic routing encapsulation (GRE) tunnel directly over a link running a point-to-point protocol (PPP) that connects the two routers. Because, the system and method run GRE sessions directly over the PPP link means there is no need to configure the GRE tunnel over an Internet Protocol (IP) connection which means that outer IP header information does not need to be sent across the link. The elimination of the outer IP header reduces the overhead in the traffic sent between the two routers.

Abstract: In an optical communication system, optical communications are transferred over a first ring and a second ring. A fault is detected on the first ring or the second ring. If the fault is detected on the first ring, a shared optical protect link is used for ring-based restoration of the first ring if the link is available, and restoration overhead for the first ring is transferred in an active location of the shared optical protect link. If the fault is detected on the second ring, the shared optical protect link is used for ring-based restoration of the second ring if the link is available, and restoration overhead for the second ring is transferred in the active location of the shared optical protect link.

Abstract: In a multi-ring network with a plurality of rings to which RPR is applied connected, high-speed failure recovery is enabled when a failure occurs between the rings. The contact nodes 700-1 and 700-3 connected to the living inter-link 505 periodically transmit and receive a KeepAlive signal to/from each other. Then, when a KeepAlive signal fails to arrive for a fixed time period, determination is made that the inter-link 505 develops a fault to broadcast-transmit an inter-link failure notification RPR-MAC frame indicative of failure occurrence on the inter-link to each node. A contact node as a transmission source of the inter-link failure notification RPR-MAC frame and each node having received the inter-link failure notification RPR-MAC frame immediately flush learning contents of their own learning data bases. A contact node connected to the spare inter-link 506 switches the spare inter-link 506 to a forwarding state.

Abstract: A data transmission apparatus for implementing multiple service flow in a multiple service ring is described. The apparatus includes a trunk pipe and at least two nodes each with at least one flow. The apparatus also includes a flow Rx framer for converting data received from the flow into data packets of a predetermined protocol, a transmission setup device for setting up information for packets of the predetermined protocol to be transmitted, and a Tx framer for encapsulating the information into frames of the MSR and transmitting the same along the trunk pipe to a downstream neighbor node along the ring.

Abstract: In a communication network including a monitor device, a relay device, and a common link terminal device, in response to detection of a link failure in a ring, each device sends a failure detection frame to the ring and causes link failure information to reach the common link terminal device. The common link terminal device generates a link failure information management database, performs a multi-failure detection process, and stops transmission of an auxiliary monitor frame upon detection of multiple failures.

Abstract: A system enabling inter-ring network connection when a plurality of ring networks are connected via a redundancy network, that is, a packet network system configured by a plurality of ring networks and redundancy networks linking the plurality of ring networks. This system virtually defines a plurality of virtual resilient packet ring networks among all of these packet networks and transfers packets on a designated virtual resilient packet ring network. Here, each virtual resilient packet ring network is identified by a virtual resilient packet ring network identifier allocated to each.

Abstract: A source node of a network transmits a path setup message for requesting a traffic path to a destination node. First and second nodes, located between the source and destination nodes, establishes first and second parallel transport paths on a first fault recovery layer between them. The first node further includes a database for storing identities of the first and second paths as a single virtual link as viewed from the source node. The first node responds to the path setup message for accommodating the traffic path on a second fault recovery layer through the first transport path. Each node accommodates the traffic path through the second transport path when the first transport path fails. The first node advertises recovery type of the virtual link as equal to the recovery type of the first and second transport paths, and/or equal to most unreliable recovery type of its component links.

Abstract: A trunk interface in Resilient Packet Ring (RPR) is provided and a method and an apparatus for implementing interface trunking in RPR with a plurality of stations, where at least one of the stations includes a plurality of RPR interfaces. A plurality of physical link ports in an RPR interface are combined into a logical link port, so as to implement logical combination of a plurality of first physical link. A trunk interface is formed with the combined logical link ports, and a logical address is assigned to the trunk interface. Furthermore, the communication traffic of the stations may be apportioned among the physical link ports, so as to provide link balance. The physical links are provided on different rings. When any fault occurs, a new ring may be formed so as to make the communication link unblocked. With the present invention, the interface bandwidth is increased, the address (MAC address/IP address) resources are saved and the interface (link) reliability is increased.

Abstract: The present invention can reestablish a communication path between two packet ring networks through another packet ring network even if a fault occurs therebetween and can prevent occurrence of broadcast storm or the like.

Abstract: To provide a technology capable of improving fault-tolerance by redundancy-structuring each of ring nodes building up a ring network with an active termination block and a non-active termination block and, if a fault occurs in the active termination block, continuing an operation by switchover to the non-active termination block. A ring node is configured such that data from a terminal side is forwarded to an active termination block and to a non-active termination block, source information of the data is determined and registered in a database, the data is transmitted to the ring from a ring-side interface, the data received from the ring is forwarded to the active termination block and to the non-active termination block, destination information of the data is determined by referring to the database and forwarded to a terminal-side interface, and the terminal-side interface selects the data from the active termination block and forwards the selected data to the terminal side.

Abstract: A motion control system and method that includes a central controller configured to generate first and second demand control signals to be used to define actuation motion of respective first and second actuators. The central controller is in communication with first and second nodes by way of a data network, each node including at least a respective actuator configured to implement at an actuator time a motion or force-related effort based upon the respective demand control signal. Each node also includes a memory configured to store at least one respective propagation delay parameter related to a signal propagation delay between the central controller and the node. A timing mechanism establishes timing at each node based on the respective propagation delay parameter so that the actuator time at the nodes occurs simultaneously. Strictly cyclic and/or full-duplex high-speed communication can be supported. The network can be wired in a ring or as a tree and with twisted pair cabling or fiber.

Abstract: A method for a communications network with a protect channel transmitting protect channel data and working channel transmitting working channel data includes transmitting the working channel data via the protect channel upon a disruption in the working channel, and restoring the transmitting of protect channel data, wherein the restoring includes applying a mesh restoration protocol to the communications network to restore the transmittal of the protect channel data. The restoring includes finding one or more alternate channels to transmit the protect channel data, the one or more alternate channels including connected working and protect channels.

Abstract: A bidirectional line switched ring network which enables high-speed operation with improved reliability because of a reduced software processing load is disclosed, and the network includes a plurality of optical transmission equipment sets connected in a ring form, wherein optical transmission equipment provided in a node on the transmission side performs transmission to each lower-order channel by attaching a transmission-side node ID, and, optical transmission equipment provided in a node on the reception side collates the received transmission-side node ID with an expected value of the transmission-side node ID having been set in advance, and when the collation does not match, the optical transmission equipment in the node on the reception side prevents a misconnection in the event of a failure by inserting an alarm indication signal.

Abstract: A method and apparatus for improving performance of a loop network, in particular a Fiber Channel Arbitrated Loop. The loop network has two loops and a plurality of dual-ported devices each with one port on each loop. The method includes selectively bypassing redundant ports on the loops by a first command means in the form of a Fiber Channel Arbitrated Loop command to balance port accesses and to reduce the loop overhead by reducing the number of ports in each loop. In the event of a fault, bypassing the port of a device by a second command means in the form of a non Fiber Channel Arbitrated Loop command and enabling all the bypassed redundant ports with a single command to all ports using the first command means. The first command means does not enable the port bypassed by the second command means.

Abstract: A data transmission apparatus used in a multiple service ring is described. The apparatus includes at least two nodes coupled to at least one aggregate pipe and at least one tributary. The apparatus also includes a tributary TX framer for converting data received from the tributary, a transmission setup module for setting up information for processing protocol packets to be transmitted, a TX framer for encapsulating the information into frames of the MSR and transmitting the same along the aggregate pipe to a downstream neighbor node in the ring, and a RX framer for receiving and deframing data frames of the MSR from a upstream neighbor node. The apparatus also includes a transiting module for transiting the frames to the TX framer, a destination tributary determining module for determining a destination tributary, and a tributary RX framer for converting and sending protocol packets to a corresponding tributary.

Abstract: A method for transmitting a packet in a wireless access network based on a wavelength identification code scheme. The method comprises the steps of connecting n number of RNCs (Radio Network Controllers) to one sub-ring where the “n” is a positive integer, and assigning a unique wavelength to each RNC; identifying a packet to be transmitted between the RNCs located within a same sub-ring using the assigned unique wavelength, and transmitting the packet through an SRC (Sub-Ring Controller); connecting m number of SRCs to one main-ring where the “m” is a positive integer, and assigning a unique wavelength to each SRC; and detaching a wavelength identification code from the packet to be transmitted between the RNCs located within different sub-rings, and transmitting the packet having the encapsulated wavelength identification code through an MRC (Main-Ring Controller).

Abstract: The invention relates to a method for protection switching in a data network network including at least two rings (ERA, ERB) with a shared span (SP2,3) and a plurality of nodes (1-4). Each ring (ERA, ERB) has an associated ring manager (RMA, RMB) for checking its associated ring (ERA, ERB) and the ring managers (RMA, RMB) have dedicated different priorities (PR1, PR2). When a failure (interruption) occurs in a shared span, a shared span node (2, 3) sends a failure message (FSP2,3) to a ring manager (RMB) of higher priority (PR1) of an associated ring (ERB), and the ring manager (ERB) unblocks its port (PB2) while the ring manager (RMA) of lower priority (PR1) maintains its port (PA2) blocked.

Abstract: In a network including a number of nodes configured to support multi-protocol label switching, a method may include forming a primary label switching path (LSP) from a first one of the nodes to the other ones of the nodes in a first direction. The primary LSP may form a first ring-like LSP including each of the nodes. The method may also include forming a secondary LSP from the first node to the other ones of the nodes in a second direction opposite the first direction. The secondary LSP may form a second ring-like LSP including each of the nodes.

Abstract: The invention relates to a method for tolerating the breakdown and/or decoupling of at least one network node in a communication network used for controlling and/or adjusting the movement of a plurality of machine parts, for example the rotation bodies in a printing machines, machine tools and other production machines, wherein the network is operated according to a closed single or multiple ring structure, in which each node communicates with the transmitter or the port of a first adjacent node by means of a receiver or a first port and with the receiver or the port of a second adjacent network node by means of a transmitter or a second port, the closed ring structure is preserved in the case of the breakdown or decoupling of at least one node, at least one network node is coupled to the network by means of a data path switching device which is actuated, in the case of the breakdown or decoupling of said node, in such a way that the communicating nodes, which exist in the network and are arranged next to eac