Abstract: A method is provided for establishing a reliable communication channel between an encapsulation node and a cluster of decapsulation nodes across a communication network. The method is implemented at the encapsulation node and comprises the following steps. A primary session is initialized with a primary decapsulation node in the cluster of decapsulation nodes during which an assigned address is received. A redundant session is initialized with a redundant decapsulation node in the cluster of decapsulation nodes. Data is transmitted to and received from the decapsulation node until a failure is detected. Once the failure is detected, data is transmitted to and received from the redundant decapsulation node instead of the primary decapsulation node.

Abstract: A system and method for stitching Ethernet networks. Communications are sent from a number of communications networks in one of two or more standards. The communications are converted from the two or more standards to a core standard. The communications are sent across a core network in communication with the number of communications networks utilizing the core standard. The communications are converted from the core standard to one of the two or more standards utilized by each of the number of communications networks receiving the communications in response to the communications reaching the number of communications networks.

Abstract: The WSAN simultaneous failures recovery method ranks each node based on the number of hops to a pre-designated root node in the network. The method identifies some nodes as cluster heads based on the number of their children in the recovery tree. The method assigns a recovery weight and a nearby cluster node to each node. Nearby cluster nodes serve as gateways to other nodes that belong to that cluster. The recovery weight is used to decide which node is better to move in order to achieve lower recovery cost. The recovery method uses the same on-going set of actors to restore connectivity. Simulation results have demonstrated that the recovery method can achieve low recovery cost per failed node in small and large networks. The results have also shown that clustering leads to lower recovery cost if the sub-network needs to re-establish links with the rest of the network.

Abstract: A receiving apparatus in a wireless communication system that involves both data transmission using a virtual transmission path in which a plurality of wireless lines of which modulation method is variable are virtually consolidated into one, and time-division multiplex transmission, includes a releasing unit that releases, when a failure occurs in a current line used in the time-division multiplex transmission, one wireless line in the plurality of wireless lines constituting the virtual transmission path from the virtual transmission path; a demodulation unit that changes a modulation method used for demodulation of the one wireless line released from the virtual transmission path by the releasing unit to a modulation method used in the time-division multiplex transmission; and a switching unit that switches line connection from the current line in which the failure has occurred to the one wireless line of which modulation method has been changed by the demodulation unit.

Abstract: Embodiments of the present invention relate to a method and device for handling a failure of a mobility management device in an ISR activated scenario. The method includes: detecting, by a serving gateway, a failure of a first mobility management device; and when the serving gateway receives downlink user plane or control plane data of a user equipment, paging, by the serving gateway, the user equipment using a downlink data notification message including identity information of the user equipment, in a first radio access network connected to the first mobility management device.

Abstract: Systems and methods are disclosed which facilitate the management of changes to a hosted network. In one aspect, a resource optimization manager obtains an identification of one or more changes to be implemented on a hosted network. The network validation manager component simulates the implementation of the identified changes and records state information associated with the monitored simulation. The network validation manager component generates a network change template that includes the information recorded from the simulation of the change to the hosted network. In another aspect, the network validation manager component can utilize network change templates to monitor the implementation of changes to the hosted network. The network change templates can then be utilized to determine whether to proceed with implementation of the change to the hosted network or whether to revert the hosted network to a condition prior to the implementation of the identified change.

Abstract: In one embodiment, detecting a failure mode of a first communication link on a first port, selecting a second communication link on a second port associated with the first port, and transmitting a profile information associated with the second port are provided.

Abstract: Embodiments of the present invention provide an integrated host and subsystem port selection methodology that uses performance measurements combined with information about active data paths. This technique also helps in resilient fabric planning by selecting ports from redundant fabrics. In a typical embodiment, host port to storage port pairs that create a path between a host and a storage device will be identified. From these pairs, a set of host port to storage port candidates for communicate data from the host to the storage device will be identified based on a set of resiliency constraints. Then, a specific host port to storage port pair will be selected from the set based on a lowest joint workload measurement. A path will then be created between the specific host port and storage port, and data will be communicated from the host to the storage device via the path.

Abstract: A method for policy-aware mapping of an enterprise virtual tenant network includes receiving inputs from a hosting network and tenants, translating resource demand and policies of the tenants into a network topology and bandwidth demand on each link in the network; pre-arranging a physical resource of a physical topology for clustering servers on the network to form an allocation unit before a VTN allocation; allocating resources of the hosting network to satisfy demand of the tenants in response to a VTN demand request; and conducting a policy aware VTN mapping for enumerating all feasibly resource mappings, bounded by a predetermined counter for outputting optimal mapping with policy-compliant routing paths in the hosting network.

Abstract: In one embodiment, a method comprises creating, in a computing network, a loop-free routing topology comprising a plurality of routing arcs for reaching a destination device, each routing arc comprising a first network device as a first end of the routing arc, a second network device as a second end of the routing arc, and at least a third network device configured for routing any network traffic along the routing arc toward the destination device via any one of the first or second ends of the routing arc; and causing the network traffic to be forwarded along at least one of the routing arcs to the destination device.

Abstract: A core network device may be configured to work with a radio access network device to determine whether to allow access to a network. Criteria that may be used to make the determination include the condition of devices and links within the core network and the radio access network, which may be determined by data received from other devices at the core network device. In another embodiment, the type of service requested, for example whether the request is for an IMS service or non-IMS service, may be used to evaluate whether the a request for access to the network should be permitted.

Abstract: A method is provided in one example and includes receiving first address information from a protected node over a first label switched path having a first label. The first address information is associated with a first network element. A second label switched path has been previously established with the first network element. The method further includes establishing a targeted session with the first network element, assigning a second label to the second label switched path, and sending the second label to the first network element over the targeted session.

Abstract: A provided information handling system includes a plurality of aggregation devices configured to distribute information in a virtual link trunk and a plurality of nodes coupled to the aggregation devices. When an aggregation device receives a reboot command, that aggregation device is configured to transmit a first message to the nodes indicating that the aggregation device is rebooting, and receive a first acknowledgement message from the nodes indicating that they will not send any information to the rebooting aggregation device. The aggregation device is then configured to reboot, receive a second message from the nodes indicating the nodes are ready to receive information from the rebooted aggregation device, transmit a second acknowledgement message to the nodes indicating that the rebooted aggregation device has rebooted and is capable of receiving information, and receive information from one of the nodes for transmission to another node.

Abstract: In a protective relay device for a three-terminal transmission line comprising terminal A, terminal B and terminal C, when for example terminal information is transmitted to a protective relay Ry-A of one remote terminal (terminal A) from the protective relay Ry-C of the terminal C, terminal information Db that was sent from the protective relay Ry-B of another remote terminal (terminal B) is transmitted, in addition to the information Dc of the terminal in question. In the same way, when terminal information is transmitted to a protective relay Ry-B of the terminal B from the protective relay Ry-C of the terminal C, terminal information Da that was sent from the protective relay Ry-A of the terminal A is transmitted, in addition to the information Dc of the terminal in question.

Abstract: A distributed fabric system has distributed line card (DLC) chassis and scaled-out fabric coupler (SFC) chassis. Each DLC includes a network processor and fabric ports. Each network processor includes a fabric interface in communication with the fabric ports of that DLC. Each SFC includes at least one fabric element and SFC fabric ports. A fabric communication link connects each SFC fabric port to one DLC fabric port. Each fabric communication link includes cell-carrying lanes. Each fabric element detects connectivity between each SFC fabric port of that SFC and one DLC fabric port over a fabric communication link. Each SFC reads a connectivity matrix from fabric element chips and sends connection information corresponding to the detected connectivity from that SFC to a central agent. A network element includes the central agent, which, when executed, constructs a topology of the distributed fabric system from the connection information sent from each SFC.

Abstract: An object is to provide a communication system that can avoid a service interruption caused by a device failure, a congestion and the like inside a cell phone system. The communication system according to the present invention includes a data transfer apparatus (11), a gateway (12) for communicating with the data transfer apparatus (11), a gateway (13) that is an alternative apparatus of the gateway (12), and a path control apparatus (14) for controlling a communication path between the data transfer apparatus (11) and the gateways (12) and (13). When the path control apparatus detects a failure condition in the gateway (12), the path control apparatus controls the data transfer apparatus (11) to transfer data that is transferred from the data transfer apparatus (11) to the gateway (12) to the gateway (13) and also notifies the gateway (13) of session information that is set to the gateway (12).

Abstract: A ring network for interchanging data between a plurality of devices arranged in a vehicle includes a ring connection and a plurality of distributors. The distributors each have a plurality of communication pairs each having a transmitting unit and a receiving unit for transmitting and receiving data. Each of the devices is connected to one of the distributors via a first communication pair, to the ring connection via a second communication pair and likewise to the ring connection via a third communication pair. A direction of data flow in the second communication pair and the third communication pair is opposite.

Abstract: A boundary node for interworking between a first network and a second network comprises first equipment for interfacing with the first network and second equipment for interfacing with the second network. The first equipment comprises a switch fabric. A first interworking interface and a second interworking interface are provided for carrying traffic between the second equipment and the first equipment. Each of the interworking interfaces is for interfacing with a respective traffic-carrying path of the second network. For traffic flow in a direction from the second network to the first network, a method comprises determining that recovery switching is required for traffic on one of the traffic-carrying paths of the second network and performs a recovery switch, using the switch fabric in the first equipment, to switch between the interworking interfaces to achieve a recovery switch between the traffic-carrying paths of the second network.

Abstract: A system for PIM vLAG fast link failover recovery includes a first vLAG switch connected to a second vLAG switch by an ISL. The first vLAG switch is connected to an upstream network device by a failed link and the second vLAG switch is connected to the upstream network device by a functional link. To recover from the failed link, the first vLAG switch transmits a ROUTEUPDATE message to the second vLAG switch upon the ISL that instructs the second vLAG switch to receive data traffic from the upstream network device and forward the data traffic to the first vLAG switch upon the ISL.

Abstract: The disclosed embodiments include a system, computer program product, and method for routing a call over a packet network. A call request may be received from a calling party to call a called party at a network address. At least one potential call path over a packet network may be determined to connect the calling party to the called party at the network address. Network performance information associated with each potential call path may be accessed and a determination may be made that each of the call paths are impaired or congested. In response to determining that each of the call paths are impaired or congested, the call may be routed over a call path other than one of the at least one potential call paths to enable the calling party to communicate with the called party.

Abstract: A system and method to provide a protection ring in an Audio Visual Bridging (AVB) network is provided. The method includes the steps of monitoring a first status of links coupled to a plurality of devices in a ring network, receiving a second status of links of other devices in the ring network, and signaling devices in the ring network to generate a logical loop-free topology based upon a stored static physical configuration, the first status of the links and the second status of links of other network devices in the ring network. The method also includes the step of determining an allocation of flows to links based on stored flow characteristics. Determining an allocation of flows to links includes programming a transmit scheduler to provide a first percentage of bandwidth for Audio Video Bridging (AVB) flows while reserving a second percentage of bandwidth for non-AVB flows.

Abstract: Embodiments of the present invention provide a protection switching method, comprises: determining that the bandwidth of at least one of the transmission paths changes; obtaining a final path bandwidth combination according to the bandwidth of the transmission path whose bandwidth changes, wherein the final path bandwidth combination is formed by bandwidths of the at least two transmission paths after the bandwidth of at least one transmission path changes; querying the stored mapping relationship between the path bandwidth combination and the channel allocation policy according to the final path bandwidth combination, and determining the channel allocation policy corresponding to the final path bandwidth combination; and performing channel switching according to the channel allocation policy corresponding to the final path bandwidth combination.

Abstract: An information processing system includes a switching device group including a plurality of switching devices that include a switching device as a root node and switching devices as leaf nodes and are connected in a tree topology. The switching device includes: a controller that, when a failure that occurs in a communication path connected to the root node side of the switching device is detected, writes identification information indicating the communication path from which the failure is detected to a flow table which stores the identification information and output destination port information so as to be associated with each other, thereby switching a plurality of communication paths; and a notification unit that, when a failure that occurs in a communication path connected to the leaf node side of the switching device is detected, notifies another switching device connected to the switching device of a position where the failure occurs.

Abstract: Aspects of the subject disclosure relate to methods for detecting a link failure between the first network device and a destination node, receiving a data packet addressed to the destination node, and rewriting encapsulation information of the first data packet. Subsequent to rewriting the encapsulation information of the first data packet, the first data packet is forwarded to a second network device (e.g., using updated address information in the packet header), wherein the second network device is paired with the first network device in the virtual port channel. In certain aspects, systems and computer readable media are also provided.

Abstract: According to one embodiment, a method for establishing a primary and redundant PW over disjoint bidirectional RSVP-TE LSPs include establishing a first bidirectional RSVP-TE LSP that includes a first upstream path and a first downstream path. The method includes transmitting a first label distribution protocol (LDP) label mapping message that includes a first transport path include field that causes the second PE router to use the first downstream path for the primary PW. The method includes establishing a second bidirectional RSVP-TE LSP that includes a second upstream path and a second downstream path. The method includes transmitting a second LDP label mapping message that includes a second transport path include field that causes the second PE router to use the second downstream path for the redundant PW.

Abstract: Managing a network connection of a switch. Software configuration information relating to the network connection of the switch is obtained, wherein the information specifies at least one VLAN connecting to the switch and a plurality of uplinks to be shared. According to the software configuration information, the plurality of uplinks is assigned to the at least one VLAN to form a corresponding connection relationship, in which relationship, each VLAN corresponds uniquely to one uplink from the plurality of uplinks. The hardware connection between the at least one VLAN and the plurality of uplinks on the hardware layer of the switch is set according to the corresponding connection relationship. Shared links may be formed in the switch, which links have multiple uplinks with redundancy, all in active status.

Abstract: A method of handling at least one uplink (UL) transmission for a communication device communicating with a first base station and a second base station comprises detecting a radio link problem between the communication device and the second base station; and stopping performing at least one UL transmission for the second base station, after the radio link problem is detected.

Abstract: Multiple redundant sources for a datastream can be established in a network, where the redundant sources are configured with the same source address. One of the redundant sources provides the datastream to a receiver of a multicast group. If the redundant source fails, another redundant source can be used in its place, ensuring the receiver continues to receive the datastream. A routing element coupled to a redundant source monitors the redundant source for failure and informs the rest of the network of the status of the coupled redundant source. The routing element can inform other routing elements of the status by advertising or withdrawing a route that reaches the coupled redundant source, which the other routing elements can use to update their routing tables.

Abstract: A communication is established between a client device and a server device, where the server device executes one or more hosted virtual desktop (HVD) applications for the client device. A media data stream including at least one of audio content and video content is transmitted from the client device to the server device, where audio and video content of the media data stream is captured by one or more input devices at the client device and is utilized by an HVD application at the server device. In response to a request for the media data stream by a second application that is local to the client device or is operating at a remote device, transmission of the media data stream to the server device is selectively suspended or shared with the second application.

Abstract: A method for adjusting bandwidth in a communications network having a plurality of nodes connected over multiple links with a plurality of services running on the links includes detecting an impairment of a link wherein the impairment invokes a reduction in bandwidth available to the services running on the link, communicating information about the impairment to other nodes in the network and redistributing services between the links to limit a bandwidth required by services running on the impaired link to a value not exceeding the bandwidth available on the impaired link.

Abstract: In one embodiment, a network device may receive an indication of a particular future message time, and determines a path validation time that is prior to the particular future message time by an amount at least long enough to detect and report a route change of a path from the network device to a source of the particular future message, wherein the source utilizes the path in reverse to reach the network device for the particular future message. Accordingly, the network device sends, at the path validation time, a keepalive message on the path, where in response to a failure of the keepalive message on the path, the network device repairs the path to the source with a particular route change, and reports the particular route change to the source, e.g., such that in response, the source may transmit the particular future message on the changed path in reverse.

Abstract: A communication comprises a plurality of digital subscriber line (DSL) links, a first node having at least one application port configured for an elastic service and a plurality of DSL ports, and a second node having at least one application port configured for an elastic service and a plurality of DSL ports. Each of the first and second nodes is configured to interleave data received over the at least one application port across the plurality of DSL ports, each DSL port allocated a set of DSL timeslots for transport of the data received over the at least one application port. When a failure is detected on one of the DSL links, each of the first and second nodes is configured to interleave the data received over the at least one application port across the remaining DSL ports not connected to the failed DSL link without adjusting the set of DSL timeslots allocated to each of the remaining DSL ports for transport of the data from the at least one application port.

Abstract: In one embodiment, forwarding information bases (FIBs) are selectively populated in a packet switch. A packet switching device determines, based on one or more protocol signaling messages, a subset, which is less than all, on which FIBs a lookup operation may be performed for identifying forwarding information for a received particular packet. The packet switching device populates each of these FIBs, but not all of the FIBs of the packet switching device, with forwarding information corresponding to the particular forwarding value. Thus, FIB resources are consumed for only those FIBs which could actually be used, and not all of the FIBs, for forwarding packets in the data plane of the packet switching device, whether these packets are received on a primary or backup path.

Abstract: A communication managing apparatus (CMA) that manages transmission of data employing a token passing system in a network in which a plurality of communication apparatuses (CAs) are connected via a transmission line. The CMA includes a network-presence checking unit performing network presence checking processing for transmitting, by broadcast, a network presence check frame for recognizing the CAs, receiving, from the CAs, frames including thereof, and generating connection information indicating a connection state via the ports. The CMA further comprises a unit determining token circulation order using the connection information, a setup processing unit performing, based on the token circulation order, setup processing for notifying the communication apparatuses of a communication apparatus to which a transmission right is giving next, and a data-fame-communication processing unit performing transmission and reception of a data frame using a token frame.

Abstract: In a method (400) for routing packets between a plurality of top switches (110a-110n) and a plurality of leaf switches (120a-120n) using a balancing table (204, 208, 210) in a fat tree network (100), a failed link between at least one top switch (110n) and at least one leaf switch (120n) is detected (402). In addition, the balancing table (204, 208, 210) is modified (406) based on the detected failed link, and the packets are routed (408) between the plurality of top switches (110a-110n) and the plurality of leaf switches (120a-120n) in the fat tree network (100) based on the modified balancing table (204, 208, 210).

Abstract: An information transmission device includes: ring-ports; an access-port; a communication-path-setting unit to facilitate or cut off communication of the ring-ports or the access-port, based on a communication setting determined such that communication paths having priority levels and assigned with same identifiers have different sections; a control-signal-transmission unit, when a communication failure occurs between one ring-port and another information transmission device, to transmit, from another ring-port, a first control signal for instructing a cutoff of communication of the access-port in the communication path having a low priority level, and transmit a second control signal for instructing a facilitation of communication of the ring-ports; an access-port-control unit, upon receiving the first control signal, to cut off the communication of the access-port in the communication path having the low priority level; and a ring-port-control unit, upon receiving the second control signal, to facilitate com

Abstract: A computing network, including: a plurality of peer computing devices including code, which when executed by a peer computing device causes the executing peer computing device to cooperate with at least one other of the peer computing devices; at least one server including code, which when executed by the at least one server locates at least one of the peer computing devices; and at least one mediator including code, which when executed by the at least on mediator collects charging information from at least some of the peer computing devices; wherein, the peer computing devices, at least one sever and at least one mediator are communicatively coupled via an at least carrier-grade telecommunications network being suitable for enhancing cooperation among the cooperating ones of the peer computing devices relative to best-efforts communications among the cooperating ones of the peer computing devices.

Abstract: Traditional computer networks have been designed with the need for highly reliable packet delivery. This is largely handled by a centrally managed simple send-acknowledge protocol. In a highly dynamic mesh network, these methods are inadequate to ensure the most reliable packet delivery. This invention uses the natural redundancy of routes in a mesh and other techniques to increase the reliability of a network, even as the paths to any given node are dynamic in nature.

Abstract: Link identifiers such as VIDs, selected from a defined range of values, are locally assigned by each node on a link state protocol controlled Ethernet network to each of its links or adjacencies. The link identifiers are assigned by the nodes such that each link or adjacency at the node is uniquely identified by a different link identifier. A link state protocol adjacency notification mechanism or other flooding mechanism is used to disseminate the locally assigned link identifiers to other nodes on the link state protocol controlled Ethernet network. The link identifiers are added by the nodes to their topology databases to enable detour routes to be locally calculated by the nodes on the network in a distributed manner. Upon occurrence of a failure, the link identifiers are used to source route traffic around the failure so that traffic may continue to traverse the link state protocol controlled Ethernet network.

Abstract: In one embodiment, a plurality of communication paths in a second direction in a communication network is determined, based on reversing communication paths established in a first direction in the communication network. Then, a path quality of the communication paths in the second direction is monitored. Based on the monitored path quality, it is then determined whether the communication paths in the second direction satisfy a communication requirement. Finally, a particular communication path of unacceptable quality in the second direction is detected when the particular communication path in the second direction fails to satisfy the communication requirement.

Abstract: In one embodiment, a source transmits one or more data packets to a destination over a primary pseudowire (PW). When a device on the primary PW detects a downstream failure of the primary PW, and in response to receiving one or more data packets from a source from the failed primary PW, the device adds a loopback packet identifier to the one or more received data packets, and returns the one or more data packets with the loopback packet identifier to the source upstream on the primary PW. Accordingly, in response to receiving the data packet returned with a loopback packet identifier from the primary PW (in response to the downstream failure), the source retransmits the one or more data packets to the destination over a backup PW.

Abstract: A method comprises: providing a wireless mobile router in a vehicle, the mobile router being operable to establish a communication link to a network management system; utilizing the mobile router to collect data independent of the router being coupled to the network management system; storing the data in the router; establishing a first communication link between the router and the network management system upon an occurrence of a first predetermined event; operating the router to upload the data to the network management system upon occurrence of the first predetermined event; and transmitting the data to the network management system via the first communication link.

Abstract: Embodiments communicate messages between mobile devices and destination devices. An exemplary embodiment includes a first border server operable to establish a first communication connection to the mobile device over a first network operating under a first protocol, a second border server operable to establish a second communication connection to the mobile device over a second network operating under a second protocol, and a transport management server communicatively coupled to the first border server and the second border server, and operable to establish a third communication connection to the destination device over a third network operating under a third protocol. The first protocol is configured to communicate a first encapsulated portion of the message. The second protocol is configured to communicate a second encapsulated portion of the message. The third protocol is configured to communicate the first encapsulated portion of the message and the second encapsulated portion of the message.

Abstract: Tools and techniques are provided to provide Voice-over-IP (VoIP) communications. On receiving a user request to initiate a telephonic connection from a local site, at which the user is using a VoIP telecommunication device which has no link failover functionality, a system establishes over wide area network links at least two tunnels between a controller at the local site and another controller. Then the system transmits VoIP traffic over at least one of the tunnels from the controller at the local site to the other controller. The system also detects failure of the primary tunnel during the call and performs failover by changing a data path during the call to transmit packets over at least one non-failed tunnel.

Abstract: A method, apparatus and system for Ethernet Ring Protection (ERP) are disclosed. The method includes: detecting, by a node, a link fault on a ring; blocking, by the node, a port connected with the faulty link after detecting the link fault, and sending a fault alarm message to other nodes on the ring, wherein the fault alarm message contains a fault identifier; and judging, by a node which receives the fault alarm message, whether the fault identifier changes; if the fault identifier changes, the node which receives the fault alarm message storing the fault identifier contained in the fault alarm message and clearing a forwarding table of the node which receives the fault alarm message.

Abstract: Disclosed are an apparatus and method of performing a data channel change-over procedure. One example method of operation may include detecting an abnormality in an active data communication channel established between at least two endpoint devices. The method may further provide selecting a next available data communication channel based on at least one data channel metric and transmitting at least one change-over message via an active control channel established between the at least two endpoints. The method may further include transmitting subsequent data messages over the next available data communication channel.

Abstract: A computer-readable recording medium stores therein a program for causing a computer to execute a process. The process includes detecting a failure of a flow indicating a route on a network through which data of each tenant service provided by a tenant via a network flows; and specifying a control target flow influenced from the flow in which the failure has been detected based on association information in which each tenant service is associated with a flow of each tenant service.

Abstract: In a communication control method: information processing apparatuses output frames to a first communication apparatus for communication; when a failure in a link between the first communication apparatus and a first one of the information processing apparatuses is detected, the first one of the information processing apparatuses switches the forwarding direction of frames containing tag information from a direction toward the first communication apparatus to a direction toward a second communication apparatus; the management apparatus searches for a second one of the information processing apparatuses which uses the tag information in common with the first one of the information processing apparatuses; and the second one of the plurality of information processing apparatus switches the forwarding direction of frames containing the tag information used in common with the first one of the information processing apparatuses, from a direction toward the first communication apparatus to a direction toward the sec

Abstract: Communication node including a transmission equipment which communicates user data with transmission equipment of an adjacent node, and a controller which communicates a message with a controller of the adjacent node and which manages the transmission equipment of its own node, wherein: a controller of the node detects existence or nonexistence of fault of a controller of the adjacent node on the basis of situation of receiving a message sent from the controller of the adjacent node; when the controller of the node detects the fault of the controller of the adjacent node, the controller of the node issues a state reference notice to a transmission equipment of its own node and checks existence or nonexistence of fault alert detection; in a case where the fault alert detection of the transmission equipment of the node does not exist, the controller of the node maintains a path state of the node.

Abstract: One embodiment relates to a method of providing dual-homing in a layer 2 switch. A determination is made as to whether a link is available to an upstream network on for a currently active port. If the link is unavailable, then the layer 2 switch a) performs a switchover such that the currently active port becomes a newly passive port, and a currently passive port becomes a newly active port, b) clears entries in an address table of the layer 2 switch, and c) spoofs MAC addresses out of the newly active link. Other embodiments are also disclosed.