Abstract: A system and method for low-cost, fault tolerant, EMI robust data communications, particularly for an EV environment.

Abstract: In accordance with an example embodiment, there is disclosed herein, an apparatus having first and second interfaces for communicating on a ring network. Upon receipt of a first signal on the first interface indicating a break in the ring, the apparatus stops forwarding packets onto the ring. Upon receipt of a second signal on the second port indicating a break in the ring, the apparatus forwards all packets destined for the ring network onto the ring network via both the first and second interfaces.

Abstract: A method and apparatus for evaluating and optimizing a signaling system is described. A pattern of test information is generated in a transmit circuit of the system and is transmitted to a receive circuit. A similar pattern of information is generated in the receive circuit and used as a reference. The receive circuit compares the patterns. Any differences between the patterns are observable. In one embodiment, a linear feedback shift register (LFSR) is implemented to produce patterns. An embodiment of the present disclosure may be practiced with various types of signaling systems, including those with single-ended signals and those with differential signals. An embodiment of the present disclosure may be applied to systems communicating a single bit of information on a single conductor at a given time and to systems communicating multiple bits of information on a single conductor simultaneously.

Abstract: A resilient virtual Ethernet ring has nodes interconnected by working and protection paths. Each node has a set of VLAN IDs (VIDs) for tagging traffic entering the ring by identifying the ingress node and whether the traffic is on the working or protection path. MAC addresses are learned in one direction around the ring. A port aliasing module records in a forwarding table a port direction opposite to a learned port direction. Each node can also cross-connect working and protection paths. If a span fails, the two nodes immediately on either side of the failure are cross-connected to fold the ring. Working-path traffic is cross-connected onto the protection path at the first of the two nodes and is then cross-connected back onto the working path at the second of the two nodes so that traffic always ingresses and egresses the ring from the working path.

Abstract: A recovery method for ring-based network comprises following steps: when an error occurs at first node, second and third nodes adjacent to the first node transmit a link-down packet respectively; after the first node is repaired, the first, second and third nodes transmit a link-up packet respectively, and each link-up packet includes a priority value of the first, second or third node; the priority values of the first, second and third nodes are compared with each link-up packet to enter the ring port of the first node, the second node or the third node into a forward status or a blocked status; and a forward link or a blocked link is formed among the ring ports of the first, second and third nodes.

Abstract: A method for providing an uplink over an access ring comprising access devices and at least one aggregation device, wherein each device of said access ring has ring interfaces connecting said device to neighboring devices in said access ring, wherein one access device of said access ring is configured as a ring master device which sends connectivity check messages on both its ring interfaces around said access ring to itself to detect a connectivity failure in said access ring, and wherein said ring master device changes a state of one of its ring interfaces depending on the detection result.

Abstract: The invention concerns a method of providing a successor list (L) for routing in a peer-to-peer overlay network (N), and a network node and a computer program product to execute this method. The peer-to-peer overlay network (N) comprises a plurality of nodes (0, 20, 50, 87, 112, 140, 179, 200, 211, 223, 240). The successor list (L) specifies identifiers of at least two successor nodes (211, 223) subsequently succeeding a first node (200) of the plurality of nodes (0, 20, 50, 87, 112, 140, 179, 200, 211, 223, 240) with regard to a topology structure of the peer-to-peer overlay network. It is determined whether the at least two successor nodes (211, 223) listed in the successor list (L) run on the same physical hardware.

Abstract: A method and system for sharing protection of a mesh network protection domain are disclosed by the present invention. The method includes: presetting a protection ring in the mesh network protection domain, a path of the protection ring running through source and destination nodes of a plurality of services in the mesh network protection domain, and only reserving protection resources on the path of the protection ring; determining protection methods used respectively by a plurality of services said above and configuring a corresponding protection group; setting protection paths of all protection groups on the protection ring, and sharing the protection resources of the protection ring.

Abstract: According to an example, a MPLS ring protection switching method is applied to each node in an MPLS TP ring. In the method, an MPLS forwarding table entry configured for a working LSP and an MPLS forwarding table entry configured for a backup LSP of the working LSP are added into a first table, an MPLS forwarding table entry formed by cross connecting the working LSP and the backup LSP is added into a second table, a packet is received, the first table is searched when the node is in a normal forwarding state, and the packet is forwarded by using an MPLS forwarding table entry in the first table, the second table is searched when the node device is in a protection forwarding state, and the packet is forwarded by using an MPLS forwarding table entry in the second table.

Abstract: It is described a method for monitoring the operational state of a telecommunication network (100) having a first level (110) comprising a plurality of managed entities (111) and a second level (120) comprising a management system (121) for the managed entities (111) of the first level (110). The described method comprises propagating a first notification (151) within the first level (110) from a first managed entity (111) to a second managed entity (111), and transmitting a second notification (161) from one of the plurality of managed entities (111) to the management system (121). The second notification (161) comprises an information being indicative for the operational state of at least one another of the plurality of managed entities (111). Preferably, the managed entities (111) are arranged within a closed loop (152) such that the first notification (151) is propagating along this loop (152).

Abstract: When a first communication device receives a predetermined message from a second communication device via a third line (L3) in a state of transmitting frames to a first line (L1) while performing error-correction coding on the frames, the first communication device switches the line used for transmission from L1 to the second line (L2), then transmits a frame of a post-switching message to L1 . The second communication device receives frames from L1 and L2 and performs error correction, stores the frames, on which error correction has been performed, in first and second buffers (B1, B2), and when determining that it is necessary to perform line switching based on the status of error correction with respect to the frames received from L1, transmits a predetermined message to L3, and when receiving the frame of the post-switching message from L1, starts reading frames from B2 after reading all frames stored in B1.

Abstract: A set of virtual local area networks (VLANs) are defined from a set of nodes that comprise a data center network. A set of possible paths are determined for routing data packets from a root node to one or more other nodes of the set of nodes. A set of probabilistic values are identified for determining a path in the set of possible paths that individual data packets are to take as between the root node and a destination node specified by the individual data packet. The data packets are routed to the destination node specified by that data packet, along a path that is determined by use of the set of probabilistic values. The path may be provided by one or more VLANs.

Abstract: A modular, high-availability network for an industrial control system employs a plurality of base modules having backplane and using network ring topology. Base modules may include I/O base modules for communicating with industrial processes or machines, an adapter base module for communicating with a programmable logic controller (PLC) and/or a bus expansion base module for providing additional I/O base modules. Base modules may be arranged side-by-side, having a backplane in a bank. Another embodiment may include having plurality of banks. The network ring topology used by the base modules is normally opened by a ring supervisor at the ring supervisor location. Upon failure of the network, the ring supervisor reconnects the ring to provide an alternative transmission path around the failure point.

Abstract: Methods for distributing content in an entertainment system are provided. The entertainment system includes a plurality of clients connected in a bi-directional loop configuration. Each of the plurality of clients has at least one associated video display unit. The method includes deriving a content distribution plan for distributing content files to the plurality of clients based on a theoretical symmetric system where each of the plurality of clients in the symmetric system is configured to store at least a fraction of each of the content files; and applying the derived content distribution plan for distributing content files to an actual entertainment system wherein each of the content files are stored in full in at least one of the plurality of clients of the system to provide an actual content distribution plan for the actual entertainment system. Related entertainment systems and content distribution modules are also provided.

Abstract: The present invention discloses a method and device for processing an alarm in a ring optical transport network. The method comprises detecting alarm information in the ring network in real-time, and when generation of only an working ODUk alarm in the ring network is detected, performing a switching process of a 1+1 protection protocol on services carried on a working channel on which an alarm is generated; in the event that one working ODUk alarm has existed in the ring network, when generation of an alarm at a protection ODUk corresponding to the working ODUk on which the alarm has been generated is also detected, or when an optical multiplexed segment layer alarm is generated in the ring network, triggering a switching process of a channel shared protection protocol. The device comprises an alarm detection module and a switching triggering module.

Abstract: A method of managing a ring-based overlay network that is configured to allow routing of messages across an underlying IP network to destinations not specified by an IP address. The method comprises firstly sending a probe message from an initiating node of the overlay network around the ring, with each peer node forwarding the probe message to a successor or predecessor node. Upon detection of a forwarding failure at a node of the ring, a Probe error message is sent from that node to the initiating node. The initiating node represents the final destination for the Probe message.

Abstract: A load management method for controlling a plurality of distributed community loads with a plurality of controllers. The controllers are connectable to a network and the distributed community loads are connectable to a power grid. The loads are controllable by a corresponding one of the controllers according to a local need and a power grid supply or a community need of the loads. A network node device adapted to communicate with other node devices of a same community within an overlay network topology system. The system has a plurality of node devices organized in a number of hierarchically linked rings. The plurality of node devices of a same ring is interconnected in groups of node devices. One of the node devices is a parent node for linking the node devices of a first ring to node devices of a second ring at another hierarchy by being a parent node to both first and second rings.

Abstract: A method of reconfiguring a data unit communication network that comprises bridge nodes is described. Each bridge node comprises two or more ports for receiving and sending data units, a controller for controlling said bridge node and for handling received data units, and a record for associating data unit address information with port identification information. The controller is capable of querying said record for determining which one or more ports to forward a received data unit to.

Abstract: Ethernet nodes, interconnected logically or physically to construct a closed loop, may be controlled using a control protocol that governs placement of blocks on the ring. The control protocol allows one of the nodes to be designated as a root node in normal operation. The root node will block data traffic on one of its ports on the ring to prevent a forwarding loop from being created on the ring. Each node on the ring performs link level connectivity detection and, upon detection of a failure, will send out a Failure Indication Message (FIM). When a node receives a FIM, it will flush its forwarding database associated with the ring and, if it is the root node, will remove the data block on the port. When the failure recovers, the nodes adjacent the failure will transmit a recovery indication message to allow the ring to revert to its normal state.

Abstract: A system, apparatus and method for a closed loop system, which can be operated over a plurality of hardware platforms. Optionally, according to at least some embodiments of the present invention, the system, method and apparatus may be used for control of an energy system.

Abstract: A method and a device are provided to be run in a network (or in particular on a network component of such network). The network has several network elements that are connected via a ring. One network element is a ring master with a primary port and a secondary port. The novel process includes the steps of (i) a failure along one direction of the ring is detected by the ring master; and (ii) the ring master sends a first message via its port that indicates the direction of the failure.

Abstract: Between a first pair of termination nodes, a first current-use packet transmission path and at least one first spare packet transmission path are defined. Between a second pair of termination nodes, a second current-use packet transmission path and at least one second spare packet transmission path are defined. When no network fault occurs, packets are transmitted between the pairs of nodes in a 1:1 transfer mode in which the pairs transfer packets via both current-use packet transmission paths only. When a network fault occurs in the first current-use packet transmission path, both transmissions are switched from a 1:1 transfer mode to a 1+1 transfer mode, in which the first pair of nodes transfer packets by using the first current-use packet transmission path and the first spare packet transmission path, and the second pair transfer packets by using the second current-use packet transmission path and the second spare packet transmission path.

Abstract: A method of managing a ring network. Bandwidth utilization metrics indicative of traffic flows within the network are derived. An optimal seam location is calculated based on the bandwidth utilization metrics. A channel block can be implemented at the calculated optimal seam location. The optimal seam location can be selected to balance traffic flows in the network, and can be updated as the distribution of traffic evolves over time.

Abstract: A method for electing a ring manager of ring topology network and a node are disclosed, where, to this end, a node responsible for electing the ring manager periodically requests each node of diagnostic information on packet traffic and receives the diagnostic information on packet traffic from each node, newly elects a node capable of performing a ring manager role, and informs each node of information on the newly elected ring manager, whereby, the ring network can be more effectively operated because the ring manager is elected based on network load status that changes in real time even in the course of a ring network being initially set up and operated responsive to structural conditions including hop count of each nod and MAC node.

Abstract: A method, system and machine-readable storage medium for providing fault tolerance in a distributed mobile architecture (dMA) system. The method includes receiving a message or failing to receive the message within a predetermined time relating to a first dMA gateway (dMAG) at a second dMAG. It is determined whether the first dMAG is not operational or is otherwise offline based on the received message or the failure to receive the message. One or more dMA nodes associated with the first dMAG are notified in order to request connections to an external system via the second dMAG. The external system is also notified to request connections to one or more dMA nodes associated with the first dMAG via the second dMAG.

Abstract: A system and method are provided for dynamically reconfiguring an optical circuit between a first node and a second node of a communication network. The system and method may include establishing a scheduling window for receiving a plurality of optical traffic demands, classifying the plurality of optical traffic demands into at least a set of bandwidth adjustable demands and a set of fixed bandwidth demands, provisioning a first set of provisioned wavelengths from the plurality of wavelengths to carry the set of fixed bandwidth demands during the scheduling window, allocating the bandwidth remaining on the first set of provisioned wavelengths to the set of bandwidth adjustable demands, and if necessary, provisioning a second set of provisioned wavelengths from the plurality of wavelengths to carry the bandwidth required by the set of bandwidth adjustable demands that could not be allocated to the first set of provisioned wavelengths.

Abstract: In a ring type network, a master node sends a measurement packet to a slave node in the backward direction and the forward direction, receives the measurement packet which has been circulated among a plurality of slave nodes, stores a received time of the backward direction measurement packet and a sending time of the forward direction measurement packet according to time-keeping of an internal clock, sends a measurement result notifying packet showing a sending time and a received time of the measurement packet to the slave node; each slave node receives the backward direction measurement packet and the forward direction measurement packet, sends the received measurement packet to the next node, stores the received time of the backward direction measurement packet and the sending time of the forward direction measurement packet according to the time-keeping of the internal clock, receives a measurement result notifying packet, calculates a time correction value using the sending time and the received time of

Abstract: A method and a system for refreshing addresses are disclosed. Said method includes: when state switching between a link fault and a fault recovery occurs in a link, a node where a port related to this link is situated refreshing an address forwarding list, and configuring a flag PF for suspending an operation of refreshing an address forwarding list on other ports of this node, and sending protocol message with address refreshing information to other nodes; and when ports of other nodes receive said protocol message, refreshing the address forwarding list only when identifier information included in this protocol message is inconsistent with identifier information stored in this port and this port is not configured with said PF flag. Said method and system judge whether to refresh the address forwarding list according to said PF flag, and determine whether to refresh the address forwarding list according to the judgment result.

Abstract: A peer-to-peer network including a set of nodes distributed among a set of processing devices and arranged in a circular form in such a way that each node has a unique successor node. Each node has a memory to store data associated with keys and, on reception of a request containing a key, provides data associated with the key. Each data item stored in the memory of a first node is duplicated in the memory of a second node, different from said first node. The second node is chosen from among the nodes deployed on the set of processing devices different from the processing device on which the first node is deployed.

Abstract: A method comprising the steps of receiving a signal indicative of a failure of a working connection in a mesh network having a headend node, a tailend node and an intermediate node, and having a protecting connection, and transmitting an activation message via the protecting connection from at least one of the headend node and the tailend node to the intermediate node for activating the protecting connection.

Abstract: Techniques are identified for optimizing the MAC flush in Ethernet rings for faster traffic restoration. In one embodiment, flushing of MAC addresses is performed only once on receiving a first control message. For example, when a first control message is received, a network device may switch from a first state to a second state, which may indicate that the MAC addresses are not to be flushed if additional control messages are received. In another embodiment, flushing of MAC addresses is performed on one ring port rather than on both ring ports. For example, a flag field of a control message header may be used to determine on which port to flush. In another embodiment, flushing of MAC addresses is performed on only one ring port of an interconnection node. For example, the ring port can be determined using a flag field and possibly labels associated with the ring ports.

Abstract: Techniques are identified for optimizing the MAC flush in Ethernet rings for faster traffic restoration. In one embodiment, flushing of MAC addresses is performed only once on receiving a first control message. For example, when a first control message is received, a network device may switch from a first state to a second state, which may indicate that the MAC addresses are not to be flushed if additional control messages are received. In another embodiment, flushing of MAC addresses is performed on one ring port rather than on both ring ports. For example, a flag field of a control message header may be used to determine on which port to flush. In another embodiment, flushing of MAC addresses is performed on only one ring port of an interconnection node. For example, the ring port can be determined using a flag field and possibly labels associated with the ring ports.

Abstract: The present invention provides a method and an apparatus for acquiring protocol messages by a ring-network node, including: using dual fields to identify different protocol messages; if a node supporting G.8032v1 receives a Force Switch (FS) or Manual Switch (MS) protocol message, determining that message is a Signal Fail (SF) protocol message according to an identifier; a node supporting G.8032v2 determining that the received protocol message is an SF or MS or FS protocol message according to the identifier. The method of the present invention enables the nodes in a ring network to accurately control the state of their own ports, thereby avoiding the case that multiple blocking points appear in the ring network and improving the network performance.

Abstract: The present invention discloses a method for refreshing a single ring address of an Ethernet ring, which method comprises: achieving address refresh on an on-ring port at one side of a same node by the control of a refresh timer. The present invention further discloses a system for refreshing a single ring address of an Ethernet ring, which system comprises: an address refresh achieving unit configured to achieve address refresh on an on-ring port at one side of a same node by the control of a refresh timer. The method and system of the present invention reduces the number of refreshes of the address forwarding table and improves the efficiency and stability of Ethernet ring protection, thus greatly promoting the performance of the Ethernet ring.

Abstract: A network switching device includes at least two stacking ports, each stacking port being connectable via a stacking cable to a stack including at least one external network switching device. The device further includes an internal communication medium coupled to the stacking ports and capable of transmitting a frequency division multiplexed signal between the stacking ports. The device further includes a network switch and an interface to enable communication between the network switch and the internal communication medium. The interface includes a parallel coupling to the internal communication medium such that a signal with one carrier frequency being communicated between the network switch and the internal communication medium does not interfere with transmission between the two stacking ports of a signal with a different carrier frequency.

Abstract: A node device in a ring transmission system in which a plurality of node devices are connected as a ring via serial links has a PHY transitioning between a normal mode and a loopback mode with timing that maintains symbol lock between an idle frame transmitted to a later serial link in the normal mode according a transmission instruction, and an idle frame from an earlier node device looped back for output to a later serial link during the loopback mode, thus performing relay processing on non-locally addressed data packets during the loopback mode.

Abstract: Embodiments of the invention describe apparatus, systems and methods for creating a protection switching domain having a control virtual local area network (vlan), a first set of high priority protected data vlans, and a second set of lower priority protected data vlans. When a fault is detected at a ring network, indicating a failed link between adjacent nodes, said fault is communicated to a master node of the ring network via the control vlan. Embodiments of the invention allow a user to specify a priority for each of its domains on a given set of ring ports. The higher priority protected data domains are serviced to completion prior to servicing the lower priority protected data domains, ensuring that data traffic convergence time does not increase across these vlans.

Abstract: A method for convergence of multicast traffic in response to a topology change. The method includes, in response to a change in a multicast topology, redirecting multicast traffic through a network device of a plurality of network devices in the multicast topology and determining a querier status of the network device. The method also includes flooding the multicast traffic through an interface to the network device to facilitate convergence of the multicast traffic. The interface is a connecting point between the network device and another network device of the plurality of network devices.

Abstract: Techniques are described which provide mechanisms for dual-homing an access ring for virtual private wire service (VPWS) Ethernet line (E-Line) services. The mechanism may provide resiliency against access ring failures and offer a restoration time of 50 msec upon failure. A method to provide such resiliency may generally include determining, at a first ring port of an access node, a ring failure in an Ethernet ring. Upon determining the first ring port of the access node is not situated on a same side of the Ethernet ring as a node designated as a ring protection link (RPL) owner, a message is transmitted on a second ring port of the access node towards a provider edge (PE) node. The message is used to activate pseudowires (PWs) at the PE node for virtual local area networks (VLANs) of the access node.

Abstract: A system including a first physical network interface card (NIC) include a number of rings, where at least one of the rings is an active ring. The system further includes a host, operatively connected to the first NIC, and including Media Access Control (MAC) layer. The MAC layer is configured to obtain a power management policy, obtain a load associated with the active ring, determine, using the power management policy and the load, that the state associated with at least one of the rings must be changed, and change, in response to the determining, the state of at least one of the of rings.

Abstract: The present invention provides for a method for reserving spare bandwidth for a link in a communication network including a plurality of links. The method provides for monitoring the volume of traffic routed through each link of the communication network. A single link failure for each link is then simulated and the volume of traffic which would be rerouted through each link for maintaining communication and the volume of traffic removed from each link are determined for each simulated single link failure. The difference between the volume of traffic which would need to be rerouted through each link and the corresponding volume of traffic removed from each link is then computed, and a maximum difference value is determined for each link for all simulated single link failures. An amount of spare bandwidth equivalent to the determined maximum difference is then reserved for each link.

Abstract: A ring network with plural network relay devices connected in a ring shape includes first and second control ports to be transitioned into either a forwarding state that permits relaying information, or a blocking state that prohibits relaying information; and a ring protocol control unit for transmitting connection confirmation information indicative of communications being possible between the first and the second control port, from the first to the second control port, and from the second to the first control port at a predetermined time interval, or for, in the event that the first or the second control port does not receive the connection confirmation information from the second or the first control port, transmitting failure information indicative of communications being not possible between the first and the second control port, from the first to the second control port, or from the second to the first control port.

Abstract: In one embodiment, a network device may detect a data plane critical fault condition, while a corresponding control plane is not experiencing a critical fault condition. In response to a network device based critical fault condition, the network device may activate and advertise an increased and expensive usable metric for each network interface of the network device. On the other hand, in response to an interface based critical fault condition, the network device may activate and advertise an increased and expensive usable metric for one or more particular network interfaces of the interface based critical fault, and signals, over the control plane to a corresponding network device at an opposing end of each particular network interface of the interface based critical fault, a request to activate and advertise an increased and expensive usable metric at the opposing end of each particular network interface.

Abstract: A system for controlling packet forwarding through a dual-homed connection between first and second network domains, the dual-homed connection including two peer nodes connected to the first and second network domains. A sub-ring network is instantiated in the first network domain, and includes at least two nodes connected in a linear topology between a pair of end-nodes. Each end-node corresponds with a respective one of the peer nodes. A virtual link through the second network domain for conveys traffic of the sub-ring network between the peer nodes, and closes the sub-ring network to define a ring topology. Each of the nodes of the sub-ring network is controlled to forward packets of the sub-ring network in accordance with a ring network routing scheme.

Abstract: A method for transmitting data in a layer two network having layer three routing capabilities includes transmitting, via a physical loopback, the data from a layer two switching component of a multi service platform to a layer three switching component of the multi service platform. The data specifies an initial routing path for the data that identifies a first layer two switch, and the method includes determining a new routing path for the data, the new routing path identifying a second layer two switch different than the first layer two switch. The method also includes updating the data to specify the new routing path, and transmitting, via the physical loopback, the data that specifies the new routing path from the layer three switching component to the layer two switching component.

Abstract: The present invention relates to a protection switching method in a communication network, the communication network including plurality of communication devices forming a linear chain and at least one non-ERPS on the nodes ERPS (Ethernet Ring Protection Switching) device connecting terminal ports of the linear chain and thereby forming a ring. In one embodiment this is accomplished by instantiating ERPS on each communication device that forms a linear chain and on each non-terminal ports of the linear chain, identifying a node or link fault in the network, wherein the link or node fault is detected by Continuity Check Message (CCM), Loss of Light (LOL), Loss of Signal (LOS), Loss of periodic continuity check messages (IEEE 802.

Abstract: A transmission system for transmitting communications data from at least one data source to a plurality of terminals via a distributor, includes terminals connected in series in a terminal chain, via an input port and an output port. The first and last terminals in the chain are directly interconnected with a shunt connection in such a way that the communications data in the chain of terminals is transmitted from terminal to terminal, between the first and the last terminals of the chain if all the terminals are interconnected, and, if the connection between the terminals in the terminal chain is interrupted, the communications data from the first terminal of the chain of terminals is transmitted in the terminal chain up to the inactive terminal and the communications data from the last terminal is transmitted in the terminal chain up to the inactive terminal.

Abstract: The present invention provides a method for updating an address table in an Ethernet ring network node and an Ethernet ring network node. When the Ethernet ring network node implements a port state switching operation and a port on the ring is switched from an unblocked state to a blocked state, the Ethernet ring network node updates its forwarding database. The method and the Ethernet ring network node of the present invention can accelerate update of the FDB in the node when a link fails or is recovered, thereby improving the convergence speed for the switching when the ring network fails.

Abstract: An optical ring network has one or more working wavelengths and multiple protection wavelengths adapted to support the working wavelength(s). Routing tables may be used in network nodes to assign traffic of a failed working wavelength to a protection wavelength. The protection technique may be applied to networks employing, for example, Dense Wave Division Multiplexing (DWDM).

Abstract: A data processing apparatus includes a receiving unit for receiving a packet, a determining unit for determining whether to process the packet data by a self-module, based on first information contained in the packet and indicating a processing order, a processing unit for processing the data if the data should be processed by the self-module, a generating unit for generating a packet containing the first information, and one of the processed data, and second information indicating that the data to be processed is stalled, and a transmitting unit for transmitting, according to the first information, the packet to a module expected to process the packet next. The transmitting unit performs the transmission at a transmission interval longer than a predetermined time, if the first and second information indicate that the packet contains data which should be processed by a module next to the self-module in processing order and is stalled.