Abstract: A method and system for metric information processing is disclosed in one embodiment. Metric information is gathered with a plurality of points of presence (POPs) geographically distributed across the Internet. The metric information is processed in a hub-and-spoke fashion with a metric reduction occurring in the POPs and another metric reduction in a kernel application server according to predetermined schemes. The two-stage metric reduction generates a result set including a data structure. The result set can be processed according to a query to generate a report. The data structure and reports have metric information that is recent and updated regularly without use of a database.

Abstract: First and second switching device are connected by a number of signal paths. The first switching device receives an instruction to switch from a first one of the signal paths to a second one of the signal paths. The first switching device performs, in response to the received instruction, a first switching operation to connect the first path, at an input of the first switching device, to the second path, at an output of the first switching device. The second switching device receives the instruction to switch from the first path to the second path and detects a loss of signal on the first path as a result of the first switching operation performed by the first switching device. The second device performs, in response to detecting the loss of signal on the first path, a second switching operation to connect the first path, at an output of the second switching device, to the second path, at an input of the second switching device.

Abstract: In accordance with a first aspect of the disclosure, a system is provided. The system includes: an optical line terminal (OLT) shelf including a plurality of optical line cards, each optical line card supporting at least one passive optical network (PON) interface for communicating with a corresponding set of optical network units (ONUs), the OLT shelf thereby corresponding to a plurality of sets the ONUs; a system card controller for controlling the plurality of optical line cards; and a DOCSIS proxy for emulating a cable modem (CM) SNMP agent for each ONU, the DOCSIS proxy being responsive to an SNP manager in a DOCSIS NMS to configure the ONUs accordingly.

Abstract: A data storage system having a pair of CPU modules each one of having a port coupled to a host computer/server and a storage medium for transferring data during an IO transfer. Each one of the modules produces different types of reset signals, one of such types being a software reset signal produced during a software upgrade of the module and other types being produced for events other than during a software upgrade, The other types produced by a first one of the modules disables the port of the first one of the modules; whereas, in response the software reset signal produced by the first one of the modules during an IO transfer, a second one of the modules couples the port of the first one of the modules to the second one of the modules to enable the IO transfer to be processed by the second one of the modules.

Abstract: An apparatus comprising a first segment endpoint bridge (SEB) configured to couple to a second SEB via a plurality of path segments, wherein the path segments comprise a working segment and a plurality of candidate protection segments, wherein the candidate protection segments comprise a protection segment that is configured to protect the working segment, wherein the candidate protection segments other than the protection segment do not protect the working segment, wherein only one first state variable is used to maintain each of the candidate protection segments other than the protection segment, and wherein a plurality of second state variables are used to maintain each of the working segment and the protection segment.

Abstract: The inventive method makes it possible to communicate in a network comprising wireless nodes provided with communications means enabling to communicate through a wireless channel and wire nodes provided with communication means enabling to communicate through a wire channel. Said method is characterised in that the wire node repeats a message received exclusively through a wireless channel if a signal acknowledging the message reception is not received, wherein the transmission of said acknowledgement signal is generated in a first time slot upon the reception of the signal though a wire channel.

Abstract: In one embodiment, when a network element is to be removed from or inserted into a network a Graceful Operations Manager schedules graceful shut-down and/or start-up routines for different protocols and/or components on the network element in an optimal order based on dependencies between the different protocols and components. The Graceful Operations Manager communicates with the different components at different stages of their shut-down or start-up process and communicates information on the standby topology across components and/or protocols to enable the synchronization of the standby topology computation on all components and/or protocols that are affected by the removal or insertion.

Abstract: A network (1) comprising a plurality of nodes (2, 3, 4), the plurality of nodes comprising a first node (A) and a second node (B), the first (A) and second (B) nodes being connected through the network of nodes (1) via a first path (2) and a second path (3), the first and second paths being different, in which the network (1) has first and second modes of operation, a first mode (108) in which traffic between the first and second nodes is transmitted over the first path (2) and not the second path (3), and a second mode (106) where the traffic is transmitted over the first (2) and second (3) paths, wherein the network (1) comprises a mode selector (10) arranged to select the mode of operation based upon a demanded level of traffic between the first (A) and second (B) nodes.

Abstract: A network element is identified from among a plurality of network elements to be used to test parameters of a network. The use of one network element to test the network provides more reliable results than using random communications from a plurality of network elements. The test network element is identified using testing pool definitions which may be provided by a network operator. The testing procedure using the single network element may use multiple pings to reduce the affect of transient responses on the network.

Abstract: A scheme to achieve fast recovery from SRLG failures in the IP layer is described. An exemplary scheme, called multi-section shortest path first (“MSSPF”), builds on the idea of IP Fast Reroute (“IPFRR”), guarantees 100% recovery of SRLG failures and causes no dead loops.

Abstract: For a ring protection method in a packet transport network a failure is detected at a first network node (N4) in the ring (1, 2). The failure is communicated along the ring (1, 2) using an automatic protection switching protocol. At the first node (N4) or at a second node (N1) adjacent to the failure, a protection switch-over for at least one protected traffic stream (4) is activated by redirecting the traffic stream (4) into the reverse direction of the ring (1, 2). Selected network nodes (N2, N5) along the ring squelch the traffic stream (4) in accordance with pre-configured squelching tables. Squelching is performed only by networks nodes along the ring which perform either an add function or a drop & continue function for the traffic stream (4) to be squelched.

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

Abstract: This disclosure describes techniques for protecting an endpoint of a label switched path. In one embodiment, a system includes an ingress router, a primary egress router, backup router, and a point of local repair (PLR) router. The ingress router, the PLR router, and the first egress router form a first label switched path. The backup router provides protection for the primary egress router such that the backup router provides routing services for the first egress router when the first egress router is not available. The primary egress router and the backup router share an anycast IP address. The backup router advertises a route to reach the primary egress router, but upon receiving a packet intended for the primary egress router, the backup router identifies the destination of the packet and forwards the packet to the destination instead of the primary egress router along a different route.

Abstract: Systems and methods are described that provide a distributed restoration signaling protocol for shared mesh restoration with standbys for transparent optical networks.

Abstract: The subject specification comprises a cognitive relay communications management (CRCM) component associated with a primary communication system, wherein the CRCM component controls relaying at least a portion of transmitted communications from a secondary source device (SSD) transmitting data to a secondary destination device (SDD) associated with a secondary communication system, in accordance with a specified relay protocol, such as a buffered decode-and-forward protocol. The CRCM component identifies when the secondary relay station (SRS) is not transmitting on the relay-destination (R-D) link and the source-relay link is not blocked, and, in such instance, allows transmission of a packet from the SSD to the SRS. The SRS forwards the packet to the SDD when the CRCM component identifies when the R-D link is not blocked. The SRS and/or SSD remove the packet from their respective queues when an acknowledgement message(s) is received from the SDD and/or SRS, respectively.

Abstract: A connection-oriented network (5) has a point-to-multipoint working path (10) between a source node (A) and a plurality of destination nodes (B-F). On detection of a failure in the working path, an indication of the failure is sent to a first node (e.g. node A) identifying the point of failure. The indication is sent via a control plane of the network. The first node selects one of a plurality of point-to-multipoint backup paths (21-25) based on the point of failure. Each backup paths connects the first node to the plurality of destination nodes. There is a point-to-multipoint backup path (21-25) for each of a plurality of possible points of failure along the working path. The backup paths (21-25) can be pre-configured to carry traffic in advance of the detection of failure. Alternatively, the first node can signal to nodes of the selected backup path to fully establish the backup path when it is required.

Abstract: A method is described of constructing a transition route in a data communication network having as components nodes and links. Upon receipt of a transition notification identifying a first component a non-neighboring node constructs a transition route around the first component. In an embodiment, a node performs detecting the first component transition; issuing a transition notification identifying the first component and recognizable by nodes configured to construct a transition route around the first component; and upon expiry of a notification transition period, issuing a transition advertisement recognizable by all nodes on the network.

Abstract: A device that uses parameters to provide multi-channel serial data transmissions and the method thereof are provided. A first serial device configures with the channel parameters corresponding to a procedure executed on a second serial device. The invention determines whether the data channel corresponding to the procedure requires sending/receiving data occupies a physical line. If so, the first serial device transmits data to the second serial device. Otherwise, the first serial device transmits a channel switch request to the second serial device. After the first serial device and the second serial device are both switched the data channel corresponding to the procedure to occupy the physical line, the first serial device and the procedure could exchange data. Therefore, the first serial device could establish new connection without closing original connection. It achieves the goal of using a single serial port to have data channels of different operation modes or connections.

Abstract: A technique is provided for dynamically discovering shared risk node group (SRNG) memberships of a plurality of interconnected edge devices in a computer network. According to the technique, each edge device “learns” the identities of its directly-attached peer devices situated in neighboring routing domains, e.g., by establishing an interior or exterior gateway routing protocol session with each peer. Thereafter, each edge device advertises the identities of its learned peers to the other interconnected edge devices. Preferably, the peer identities are distributed in novel “peer-router” extended community attributes transported in Border Gateway Protocol (BGP) messages. After an edge device has learned the identity of its own peers and received the identities of the other edge devices' peers, the device can automatically detect SRNG memberships in the computer network. Specifically, edge devices that advertise the same peer are determined to participate in the same SRNG.

Abstract: A transmission network according to the present invention includes an ingress transmission apparatus and relay or egress transmission apparatuses in network channel setting terms, wherein the ingress transmission apparatus includes a switching table in which to register in advance a channel to switch to from a certain channel in the network; a path calculation unit which calculates a channel path in said network and searches for a path to set; a channel switching unit which switches a failed channel in the network to a channel registered in the switching table or a channel searched by a path calculation unit, and a channel setting/removal unit which sends a SET CHANNEL or REMOVE CHANNEL instruction to the relay or egress transmission apparatus.

Abstract: Aspects of the invention provide apparatuses, systems, and methods for supporting cable redundancy in a network connecting a network controller (101) and an I/O device (109) (an adapter). An adapter includes a first port (407) and a second port (409) for receiving the same messages from a scanner (301) over a first and second transmission media (353, 355), respectively. A connection manager module (423) instructs a switching module (419) to direct the output data contained in the first message to a data structure (421) when the first transmission medium is operational and to direct the output data contained in the second message to the data structure when the first transmission medium is non-operational. Also, the adapter formats a message from input data.

Abstract: A method, a device, and a system for protecting a multicast traffic in the field of mobile communication are provided. A backup path is set up for a path that needs to be protected. Route information of the backup path is pre-stored in an entry of a route table. When a failure of the path is detected, a traffic is switched from the failed path to the backup path. By setting up a unicast tunnel or a multicast tunnel as the backup path for a working path in the multicast in advance, and by adding a backup path port as an ingress port of an entry of the route table, it realizes to switch a data flow to the backup path at a forwarding layer without being detected by a user when the working path failure occurs, realizes a fast convergence, and does not influence a user experience, thereby effectively reducing the influence on the user experience when the failed path is restored in a point-to-multipoint service.

Abstract: Described is a system and method of protection switching in an Ethernet network. First and second point-to-point Ethernet links are established to data equipment. Identical streams of Ethernet traffic are received at a first Ethernet port and at a second Ethernet port. The stream of Ethernet traffic being received at the first Ethernet port is transmitted to the data equipment over the first point-to-point Ethernet link, while the second Ethernet port is prevented from transmitting the stream of Ethernet traffic received at the second Ethernet port. During a protection switch, transmission of Ethernet traffic ceases over the first point-to-point Ethernet link, and commences over the second point-to-point Ethernet link, the second Ethernet port transmitting the stream of Ethernet traffic being received at the second Ethernet port to the data equipment.

Abstract: Characterization and enhancement of a mobile local scattering environment. The system includes a channel component and a link control component, wherein the channel component facilitates communication of a ping signal, which is used to estimate the delay spread characteristics and/or angle of arrival in order to characterize the mobile local scattering environment. This information is sent to the link control component, which enhances radio link performance based on the received information. The system can be used to assist in E-911 location applications, such as determining the location of an indoor user.

Abstract: A technique dynamically activates a secondary Traffic Engineering Label Switched Path (TE-LSP) at a secondary head-end node upon failure of a primary TE-LSP in a computer network. According to the novel technique, a primary head-end node establishes the primary TE-LSP having a primary bandwidth (BW) amount to a primary tail-end node. Also, the secondary head-end node establishes the secondary TE-LSP having zero BW to a secondary tail-end node (e.g., the same as the primary tail-end node). The secondary head-end node monitors the state of the primary TE-LSP, and in response to a failure (e.g., or other state change) substantially immediately adjusts the BW of the secondary TE-LSP to the primary BW amount (“activating” the TE-LSP). A “prior-hop” node to the primary and secondary head-end nodes originally forwarding traffic to the primary head-end node, may then begin forwarding traffic to the secondary head-end node, and thus onto the adjusted secondary TE-LSP.

Abstract: A communication link is established with a packet-communications device. According to an example embodiment of the present invention, a network connection is established between the packet-communications and a server to pass data such as requests and responses, as well as files, media, streaming and other data. The network connection is a tunneled connection, facilitating the communication of data using a particular protocol that may be different from or otherwise incompatible with the data being communicated. The tunnel is divided into two or more logical communications channels, facilitating the multiplexing of data (e.g., request/response pairs) onto a single physical network connection.

Abstract: A routing mechanism, service or system operable in a distributed networking environment. One preferred environment is a content delivery network (CDN) wherein the present invention provides improved connectivity back to an origin server, especially for HTTP traffic. In a CDN, edge servers are typically organized into regions, with each region comprising a set of content servers that preferably operate in a peer-to-peer manner and share data across a common backbone such as a local area network (LAN). The inventive routing technique enables an edge server operating within a given CDN region to retrieve content (cacheable, non-cacheable and the like) from an origin server more efficiently by selectively routing through the CDN's own nodes, thereby avoiding network congestion and hot spots.

Abstract: In the terminal affiliation switchover system of the invention, in the case of allocation of an IP address to one terminal in a VPN#1 in response to an IP address allocation request, a DHCP server module 121 changes registry information in a DHCP table 122 provided for the VPN#1 and simultaneously makes the change of the registry information reflected in registry of a DHCP table 222 provided for a VPN#2 via a DHCP server module 221. Similarly in the case of allocation of an IP address to one terminal in the VPN#2 in response to an IP address allocation request, the DHCP server module 221 changes the registry information in the DHCP table 222 for the VPN#2 and simultaneously makes the change of the registry information reflected in the registry of the DHCP table 122 for the VPN#1 via the DHCP server module 121.

Abstract: A distributed computing system manages execution of jobs and their associated tasks. A broker manages assignment of computing tasks from clients to available computing resources. Clients and available computing resources contact the broker by polling. To prevent “ringing,” the broker specifies wait times for the polling entities, and randomizes the wait times in a range around a desired target latency. That is, a pseudo-random number generator is used to select values within a range of the target value, to avoid the situation in which deterministic patterns in the polling and response times result in highly synchronized message traffic, which might otherwise overwhelm the broker and/or the communication network.

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

Abstract: A method performed by a provider edge device includes generating pseudo-wire tables based on virtual private local area network service advertisements from other provider edge devices, where the provider edge device services customer edge devices, and establishing pseudo-wires with respect to the other provider edge devices, based on the pseudo-wire tables, where the pseudo-wires include an active pseudo-wire and at least one standby pseudo-wire with respect to each of the other provider edge devices. The method also includes generating and advertising VPLS advertisement to the other provider edge devices, detecting a communication link failure associated with one of the customer edge devices in which the provider edge device services, and determining whether the at least one standby pseudo-wire needs to be utilized because of the communication link failure.

Abstract: A method performed by a network device may include establishing performance-based Bidirectional Forwarding Detection (BFD) sessions for each link of a primary traffic engineering Label Switched Path (TE-LSP) and establishing performance-based BFD sessions for each link of a secondary TE-LSP. The method may also include, monitoring performance of the primary TE-LSP based on the performance-based BFD sessions for each link of the primary TE-LSP and monitoring performance of the secondary TE-LSP based on the performance-based BFD sessions for each link of the secondary TE-LSP. The method may further include determining that the performance of the primary TE-LSP is degraded based on the monitoring of the performance of the primary TE-LSP and automatically switching a flow of data unit traffic from the primary TE-LSP to the secondary TE-LSP when the performance of the primary TE-LSP is degraded.

Abstract: The present invention discloses a method and system for group optical channel shared protection. In the invention, when a failure occurs, operations are performed on an optical wavelength group, and four actions are accomplished at the time of switching: switching the affected optical wavelength group on the working fiber to a backup fiber (Steer); switching the optical wavelength group whose destination node is the current node on the backup fiber to the working fiber (Copy); making the optical wavelength group whose destination node is not the current node on the backup fiber transparently pass through the current node (Pass Through); and blocking or stripping the backup wavelength group transferred on the backup fiber (Strip). In addition, the invention further discloses a plurality of node structures for realizing the above operations.

Abstract: Systems and methods for handling a transition of a roaming mobile user device (i.e., a roaming client) from one access point (AP) to a target AP, referred to herein as soft inter-AP handoff. This technique involves a second mobile user device that is already connected with the target AP, called a roaming coordinator, assisting in handoff coordination between the APs. This coordination includes assisting the roaming client in establishing a client-to-client connection to relay data traffic during the handoff, while the roaming client establishes a connection with the target AP using traditional techniques. Soft inter-AP handoff allows a faster hand-off between APs than traditional techniques, and may reduce jitter in communications with the roaming device during the transition.

Abstract: A database stores updated information concerning protected communications services. A base station for a coexisting, and potentially co-channel, non-protected communications service makes an inquiry of the database requesting an identification of geographically relevant protected services along with the database stored information pertinent to each of those identified protected services. The returned information is processed by the base station to determine what channels are available for use by the non-protected service. An available channel is identified by the base station as the working channel for the non-protected service and the base station initiates a process to establish a communications network using the non-protected service and the selected working channel.

Abstract: Techniques for recovering from hierarchical virtual private LAN service (HVPLS) hub connectivity failure are described herein. In one embodiment of the invention, a provider edge network element reuses an HVPLS spoke connectivity failure recovery mechanism in an MTU to protect against a failure of HVPLS hub connectivity. The PE network element monitors hub facing connectivity elements and declares a hub connectivity failure upon a certain amount of those hub facing connectivity elements failing, and fabricates a failure of its spoke facing connectivity elements causing the MTU to detect an HVPLS spoke connectivity failure and switch to a secondary HVPLS spoke connection. Other methods and apparatuses are described.

Abstract: Provided is a multicast path management method for a connectionless communication. Also provided is a path protection function which is effective when a path has failed. A network is formed by a trunk and a branch path. The multicast path is managed by end-to-end and when a failure has occurred, an instruction is issued from the apex of the multicast tree to respective end-to-end paths so as to switch from the currently used channel to a backup path. Thus, upon failure, an individual path protection can be performed without affecting other parts of the tree to which the same multicast flow as the defective path is distributed or the distribution state of the multicast flow.

Abstract: Systems and methods are disclosed which relate to the sending and receiving of multimedia files between two devices while connected through a voice call. These devices are free to send any type of file through a direct connection without the need to hang up and call back just to see if the file was sent successfully. These methods work for a plurality of cellular and computer devices connected through a cellular network or other Internet Service Provider.

Abstract: A technique for calculating local repair paths through a computer network using one or more dynamically measured parameters in place of, or in addition to, statically assigned cost metrics. The dynamically measured parameters include various statistical measures of resources and attributes associated with data links and/or network nodes in the computer network. In operation, an intermediate node monitors a set of local link and/or node parameters. The node may generate an advertisement in response to at least one of its monitored parameters crossing a predetermined threshold value or changing value by a predetermined percentage or amount. The advertisement is “flooded” so as to advertise the dynamically measured parameter value to other neighboring intermediate nodes. After receiving the advertisement, each node may recalculate one or more local repair paths based on the advertised parameter value. The node may utilize a recalculated repair path if it provides an appreciably lower-cost path, e.g.

Abstract: A method for estimating restoration capacity for a communication network includes a specified number of restoration paths, which can be maximally diverse from each other.

Abstract: In one embodiment, a sliced tunnel is signaled between a head-end node and a tail-end node. One or more fork nodes along the sliced tunnel are configured to furcate the sliced tunnel into a plurality of child tunnels of the sliced tunnel. Also, one or more merge nodes along the sliced tunnel are configured to merge a plurality of child tunnels of the sliced tunnel that intersect at the merge node.

Abstract: There is described a network having redundancy properties, an Ethernet switch, and a method for configuring the network. At least two network segments which are formed with a plurality of Ethernet switches are connected to one another by means of a redundant connection comprising at least two coupling channels. During configuration, a programming device stores a logic name for the redundant connection in the respective memory of associated coupling devices. In a network startup phase, said coupling devices determine the respective other connection partner associated with the same redundant connection by distributing special messages in which they enter the logic name of the redundant connection. They use an order criterion to determine which coupling channel is active and which coupling channel is deactivated during trouble-free operation.

Abstract: In a communications network having a plurality of nodes adapted to communicate with each other, and more than one path available between most source-destination node-pairs, a network interface is associated with each node. Each network interface has a plurality of route tables for defining a plurality of routes for transferring each packet from a source node to a destination node. Each network interface further includes a path status table of path status indicators, e.g., bits, for indicating whether each route in the route tables is usable or is unusable as being associated with a fault. The network manager monitors the network to identify faults and provides the path status indicators to the respective network interfaces. Failed routes in the network are avoided based on the path status indicators. When a failed route is restored, such that the route is usable again, the path status table indicates that the usable state is restored.

Abstract: A method for managing traffic flow through a multipath network and systems and apparatuses configured to employ such a method are provided. The method includes forwarding a packet along a first link of the multipath network and tracking a load of the first link subsequent to forwarding the packet. In addition, the method includes preserving the first link for a subsequent packet having the same flow address as the forwarded packet upon determining a desired load change of the first link is less than a predetermined value.

Abstract: Certain exemplary embodiments can provide a method, which can comprise, from a central routing device of a plurality of central routing devices, automatically polling each of a plurality of Provider Edge routers with Bidirectional Forwarding Detection protocol messages. The method can comprise automatically determining a suspected failure of a Provider Edge router of the plurality of Provider Edge routers.

Abstract: A redundancy control method is disclosed that controls a first redundancy function that switches between a working line and a protection line in response to a detection of a line error and a second redundancy function that performs a path switching in response to a detection of a path error in a ring network operating at a path rate lower than a line rate thereof. The method comprises a step of masking the path error detection within a period from a time of the detection of the line error to an expected time of the detection of the path error.

Abstract: A computer system automatically recovers from a split segment condition in which a contiguous layer 2 network segment, comprising a plurality of contiguous paths each directly coupling one or more members of a team of network resources of the computer system to a core switch of a layer 2 network, is split into two or more noncontiguous segments each comprising a contiguous set of one or more of the plurality of paths. The computer system includes a team of network resources having one or more members that couple it to each one of the plurality of paths. A teaming driver binds the drivers of each member of the team and is coupled to the segment through the members of the team.

Abstract: When half-duplex many-to-many communication is performed among a plurality of mobile stations having different codecs in a single group, transcoding is performed with a small number of codec circuits. A transcoder manages an SSRC of a received RTP packet, detaches voice information from a jitter buffer, which is identical to a latest SSRC, and inputs the detached voice information to a codec circuit. As the latest SSRC is switched, a voice sending station subject to transcode is switched, and mobile stations using the same codec share the codec circuit. Therefore, in a half-duplex many-to-many communication (group communication) system, called a professional mobile radio system, push-talk, or press-talk, it is not necessary to switch the transcoder until a radio station which takes a talk burst is changed during a single call (call session).

Abstract: A method for configuring IP network resource and an IP network are disclosed. The method includes: configuring a Plane A and a Plane B to have a reciprocal master-slave relation and to carry services individually, wherein the Planes A and B are connected with each other in a carrying network; configuring two interfaces of an access device with a reciprocal master-slave relation and assigning IP addresses to the Planes A and B respectively, to connect the Plane A with the Plane B; and distributing services to the IP addresses of the two interfaces in turn in the case that the IP address of a peer access device of the access device is unknown. The presently described technology can be easily implemented and can improve the network quality of service effectively, which can solve one or more problems in the conventional master-slave bi-planes networking, such as insufficient usage of the network resource, complex network policy configuration, etc.

Abstract: An extra traffic is transmitted in a redundant communication network using a backup path. A working communication path and the backup communication path connect two switching nodes. A switching control packet including information representing whether a first traffic passes through the working communication path is transmitted between the two switching nodes via the backup communication path. Under normal conditions, the first traffic passes the working communication path. A backup node that has received the second traffic from outside the backup communication path, determines whether the first traffic is passing through the working communication path based on information included in the switching control packet. If the first traffic is passing through the working communication path, the backup node transmits the second traffic to another backup node along the backup communication path.