Abstract: A network relay apparatus includes: a clock generation circuit, a processing circuit, a load detector and a clock cutoff circuit. The clock generation circuit is configured to generate a clock signal having periodical clock pulses. The processing circuit is configured to operate in synchronism with the clock pulses, in order to process data that is to be relayed by the network relay apparatus. The load detector is configured to detect a load of processing by the processing circuit. The clock cutoff circuit is configured to cut off supply of the clock pulses from the clock generation circuit to the processing circuit in order to partially eliminate the clock pulses at a rate corresponding to the load detected by the load detector and to provide the clock signal having the partially eliminated clock pulses to the processing circuit.

Abstract: A simple configuration for cooling comprises a front-back air supply and exhaust system. A first circuit board is located in front of a relay circuit board. A cooling unit and a second circuit board are placed behind the relay circuit board in a chassis. A first air passage allows intake air through an intake hole in a front side of the first circuit board unit to pass through the first circuit board and then through an opening in the relay circuit board to the cooling unit. A second air passage allows intake air through an intake hole in a front face of the chassis to pass through a lateral side of the first circuit board and then through a vent hole in a partition provided at the lateral side of the first circuit board. The second circuit board is placed in the second air passage.

Abstract: A network relay system includes a plurality of communication devices 1000. Each of the communication devices includes a data plane 20 that transfers an input packet according to routing information, and a control plane 1100 having a processing unit 1110 that learns the routing information, and a control system repeater 1120. The data planes 20 of the respective communication devices can realize a non-blocking communication therebetween. Also, the control system repeater 1120 of an operational system receives the routing information from the processing unit 1110, sets the routing information for the data plane 20 of the subject communication device, and transmits the routing information to the control system repeater 1120 of the other communication device 1100-2. The control system repeater 1120 of a standby system receives the routing information, and sets the routing information for the data plane 20 of the subject communication device.

Abstract: A packet relay device is equipped with a buffer memory including a plurality of queues for temporarily storing packets, and a storage unit for storing the first queue lengths indicating the respective queue length of each of the queues and a second queue length indicating a value according to a total of the plurality of first queue lengths. When the packet relay device receives packets, it discerns the queue to which the received packet belongs from among the plurality of queues, and temporarily stores the packet in relation to the discerned queue within the buffer memory. Then, the first queue length and the second queue length are updated, and a determination is made of whether or not to send a congestion notification to the packet sending source according to the first queue length corresponding to the discerned queue, and to the second queue length.

Abstract: Network repeaters which each implement a redundant switching function previously grasp connection states of ports of a network system by using an inquiry frame and an exchange frame. At the time when a line is broken, when actively confirming a state of a port connected to a port in which a line is broken via a downstream device, the network repeaters each grasp that which portion of the line is broken and determine whether a switchover is required. Through the process, the network repeaters each prevent a useless switchover such as switching-back immediately after the switchover, and at the same time since a mechanism of waiting for a given length of times is not required, they each perform a fast switchover.

Abstract: When burst traffic causes a packet to overflow or to be ready to overflow from a queue, a packet relay apparatus mirrors only the packets to be accumulated in that queue. An outgoing queue management unit copies a packet into a queue in an outgoing queue list and then obtains the length of the queue (step 272). If the queue length is greater than a mirroring starting threshold, the value of the mirroring on/off flag in the corresponding queue entry is changed to ON (step 275). If the queue length is smaller than a mirroring stopping threshold, the value of the flag is changed to OFF (step 274). After the queue length exceeds the mirroring starting threshold until the queue length becomes smaller than the mirroring stopping threshold, only the packets to be output to that queue are mirrored.

Abstract: A switch apparatus providing with a loop detection function sets a port identification to a port which activates the loop detection function, only receives the loop detection frame by a high-order port in the switch apparatus connected with a backbone network or a high-order switch apparatus on the basis of the port identification set previously, and controls an inactivation of a sending source low-order port that sent the loop detection frame, when the loop detection frame is received by the high-order port.

Abstract: A packet relay device comprises a distribution processing unit classifying traffics into groups and users based on header information of packets received; a calculation unit calculating available frame rate of each user from peak frame rate, minimum frame rate, and weight information set for each user; a scheduling control unit updating a transmission schedule point-in-time calculated based on the available frame rate of each user, and judging which packet should be transmitted in accordance with the transmission schedule point-in-time updated; and a shaping unit updating a transmission schedule point-in-time calculated based on the peak frame rate of each user, and performing a shaping of packets at the peak frame rate on each user basis in accordance with the transmission schedule point-in-time updated; and a priority-control processing unit performing a strict priority control over transmission of packets of each group in correspondence with degree of priority of each group.

Abstract: A fault that cannot be autonomously detected by all or a specific software module and all or a specific hardware device which realize the packet transmitting/receiving function is detected, and also a fault part is specified. A packet relay device realizes the packet transmitting and receiving functions through plural software modules and plural hardware devices. The packet relay device includes a memory space 105, reception statistics 131, 133, 135, and transmission statistics 132, 134, 136, and collects pass information of fault monitoring packets in all or the specific software module and all of the hardware devices whose operation is to be confirmed by the fault monitoring packets for detecting the faults within the device. A fault part specifying unit 118 is provided for specifying the fault part according to the pass information of the fault monitoring packet when abnormality is detected.

Abstract: In an electronic device, when a 48 V feed system is shifted to a 12 V feed system, in order to supply the same electric power, a current of fourth times needs to flow into a backplane. Also, in an anteroposterior intake and exhaust system, there is a need to form a ventilator through which a cooling air passes in the backplane. Further, there arises a problem that a mechanical strength is deteriorated by provision of the ventilator in the backplane. There is provided a structure in which a pinnate projection is provided on a feed bus bar, and a cooling air is applied to the feed bus bar. Also, the feed bus bar is brought into close contact with an overall surface of the backplane, and electrically and mechanically connected thereto at multiple points, to thereby perform both of cooling and the suppression of stiffness deterioration.

Abstract: A network system includes: a core switch; and an edge switch. The edge switch includes: a join message identification unit; and a marking unit. The join message identification unit identifies a join message from among MAC frames from the user network. The marking unit marks mark information to a header of a MAC-in-MAC frame in which the identified join message is encapsulated. The core switch includes: a plurality of input/output ports; a mark identification unit; and a port setup unit. The mark identification unit identifies a MAC-in-MAC frame to whose a header the mark information is marked. The port setup unit associates a multicast group of a join message which is encapsulated in the identified MAC-in-MAC frame, with an input/output port to which the identified MAC-in-MAC frame is input.

Abstract: A network management apparatus is previously registered with a physical connection relationship and positional information of a plurality of network relay apparatuses which form part of a network, as well as a configuration definition corresponding to the positional information, such that the network management apparatus can initially detect network relay apparatuses connected to the network management apparatus, and distribute a configuration definition, which takes into account a connection relationship, to the network relay apparatuses connected thereto to set the configuration definition in the network relay apparatuses in order. In this way, even if wiring is freely made, the configuration definition which should be set in each network relay apparatus can be appropriately distributed to and set in one adjacent network relay apparatus to another. Upon occurrence of a fault, the network can be appropriately recovered by a previously set recovering scheme.

Abstract: An information processing device implements error control including at least one of error detection and error correction. The device comprises an information bit sequence acquiring unit and an encoder. The information bit sequence acquiring unit acquires an information bit sequence. The encoder generates a redundant bit sequence enabling execution of error control of the entire information bit sequence, the redundant bit sequence being generated through encoding by a predetermined code based on the information bit sequence and generates a codeword that includes the information bit sequence and the redundant bit sequence. The encoder generates the redundant bit sequence in such a way that one or more bits contained in the redundant bit sequence each functions as a parity bit for one of a plurality of divided information bit sequences produced by dividing the information bit sequence.

Abstract: In a transmission system of transferring a packet input from a first device to a second device via a network, a receiver device comprises a storage module configured to successively accumulate received packets, which are transferred over a multiple transmission paths, in correlation to each of the multiple transmission paths, a packet selector configured to sequentially perform a packet selection process with respect to each of the received packets accumulated in the storage module, where after elapse of a predetermined time period since a receipt time of a first packet received by the receiver device, the packet selection process respectively reads out one packet for each of the multiple transmission paths among the received identical packets, which are accumulated in correlation to each of the multiple transmission paths, and selects one packet with higher reliability out of the read-out packets, and an output module configured to output the packet selected by the packet selector to the second device.

Abstract: A packet forwarding device changes packet transfer performance according to a packet load, and ensures communication quality of an important packet while transfer performance is made minimum to suppress power consumption. The packet forwarding device includes a measuring section to measure the packet load for each packet importance degree, an estimation section to estimate a future packet load for each importance degree based on the measurement result, a performance determination section to determine performance for an operation based on the estimated load, which are provided in, for example, a traffic estimation/performance determination section. Reduction in the power consumption and assurance of the communication quality of the important packet are realized by a minimum performance determination based on an important packet estimation load in the performance determination section and a preferential process of the important packet in the packet forwarding device.

Abstract: A network management/apparatus connected to a plurality of packet relay apparatuses constituting a group through a network includes an energy saving level calculation unit for calculating an energy saving level of each of the packet relay apparatuses on the basis of a CPU usage ratio of the packet relay apparatus managed or a difference between the present energy saving level and the energy saving level of minimum guarantee of the packet relay apparatus, and an energy saving function setting unit for setting an energy saving function of the packet relay apparatuses on the basis of the energy saving level calculated by the energy saving level calculation unit.

Abstract: The network system is provided. The network system includes: a first processing apparatus configured to provide a specific service; a second processing apparatus configured to provide the specific service, the first processing apparatus and the second processing apparatus having one identical address; a client apparatus configured to utilize the specific service; and a network relay apparatus connected directly or indirectly via interfaces to the first processing apparatus, the second processing apparatus, and the client apparatus and configured to relay packet transmission between the client apparatus and the first processing apparatus or the second processing apparatus, wherein the network relay apparatus forwards a received packet, which is received via the interface connecting with the client apparatus to be sent to the address as a destination, to one processing apparatus in a state enabled to provide the specific service between the first processing apparatus and the second processing apparatus.

Abstract: The network relay apparatus is provided. The network relay apparatus includes: multiple ports, each being provided to send and receive a frame to and from one of multiple external devices; and a frame processor configured to perform flooding, in order to relay a received frame that is received via one of the multiple ports as a receiving port, with a preset flooding target according to an attribute of a transmit port that sends the received frame.

Abstract: Network switching arrangements including: setting an operation mode of a target switching block to a operation mode that is different from an operation mode of a first switching block while the first switching block is handling a switching process, the target switching block being one switching block selected from second switching blocks; performing a switchover process including starting the switching process using the target switching block instead of the first switching block, after completion of setting the operation mode of the target switching block; and copying the switching information held by the first switching block to the target switching block, prior to starting the switching process using the target switching block, after completion of setting the operation mode of the target switching block.

Abstract: The network relay apparatus is provided. The network relay apparatus includes: a main controller; a relay processor; and, a network interface unit configured to include: a plurality of line interfaces to which physical lines are respectively connected and send and receive a packet to and from outside of the network relay apparatus; a data storage configured to store circuit data; a programmable logic device by with a logic circuit having a predetermined function is realized; a configuration circuit configured to direct the programmable logic device to configure the logic circuit using the circuit data; and a state controller provided in a circuit structure other than the programmable logic device to control state of each of the plurality of line interfaces to one of an active state which allows data transmission and reception and a standby state which prohibits data transmission and reception.