Abstract: A packet transfer device including: a first storage that stores a first priority packet; a second storage that stores a second priority packet having a lower priority than the first priority packet; a first reader that reads the first priority packet stored into the first storage before storing the first priority packet into the first storage is completed; and a second reader that reads the second priority packet stored into the second storage after storing the second priority packet stored into the second storage is completed.

Abstract: A transmission device includes: a signal receiving part configured to receive a time division multiplexing signal in which a plurality of packets are stored; a separating part configured to separate the plurality of packets from the time division multiplexing signal; an assigning part configured to assign an identifier corresponding to a stored position in the time division multiplexing signal to each of the plurality of packets; and a packet transmitting part configured to transmit at least two packets having different identifiers out of the plurality of packets through a common transmission path.

Abstract: A transmission device includes: a code generator configured to generate delay measurement information; an insertion unit configured to sequentially insert the delay measurement information generated by the code generator, in each of delay measurement signals in a plurality of frames, and to sequentially transmit the plurality of frames sequentially inserted with the delay measurement information to a counterpart device on a transmission path whose path delay time is to be measured; and a detector configured to receive a plurality of frames transmitted from the counterpart device and to detect the delay measurement information included in each of delay measurement signals in the plurality of received frames.

Abstract: There is provided a communication device in a communication system in which a plurality of communication devices are coupled in series, the communication device including: a memory; a processor coupled with the memory and the processor configured to: receive a control signal included in a signal transmitted from a first communication device of the plurality of communication devices, control an output band in which the communication device transmits the signal, based on a weight value included in the control signal received, update the weight value, and transmit the signal including the control signal including the weight value updated, to a second communication device of the plurality of communication devices through the output band controlled.

Abstract: A transmission device includes: a first counter; a counter control unit configured to increment the first counter at a specified rate; a frame buffer configured to store a received frame; and a buffer control unit configured to read a frame from the frame buffer when a value of the first counter is larger than a specified threshold and output the frame. When a length of an output frame read from the frame buffer by the buffer control unit is shorter than a specified reference frame length, the counter control unit decrements the first counter by a value indicating the reference frame length. When the length of the output frame is longer than or equal to the reference frame length, the counter control unit decrements the first counter by a value indicating the length of the output frame.

Abstract: A collision detection unit detects whether a first entry that is associated with a value obtained by hashing a first MAC address is present in each area in a MAC address table and detects whether a second entry that is associated with a value obtained by hashing a second MAC address is present in each area in the MAC address table. If the first entry is present in each of the areas, a collision avoidance control unit acquires the second MAC address stored in the first entry that is present in one of the areas and inputs the second MAC address in the collision detection unit. If the second entry is not present in any of the areas in the MAC address table, a registration unit stores the second MAC address in the second entry and stores the first MAC address in the first entry.

Abstract: There is provided a communication apparatus including a hardware processor configured to: count numbers of transmissions and receptions of a measurement frame assigned between frames when a communication of an active system is performed, by an active system counter, count numbers of transmissions and receptions of the measurement frame when a communication of a standby system is performed, assign switchover indication information for indicating an occurrence of the switchover from the active system to the standby system, to the measurement frame to be transmitted to other communication apparatus, and measure a data loss based on a count value of the active system counter or the standby system counter, by excluding frames transferred during a period of time from a transmission of the switchover indication information to a reception of the reception indication information transmitted from the other communication apparatus which has received the switchover indication information, from a measurement target.

Abstract: There is provided a frame transfer apparatus, which includes: a storage unit configured to store an address and a port in association with the address; a receiving unit configured to receive a frame; a switch unit configured to determine an output port based on a destination address of a received frame; and a transmitting unit configured to transmit the received frame, from the output port determined by the switch unit, wherein the switch unit includes a copying unit configured to copy the received frame when the destination address of the received frame has not been stored in the storage unit, and a rate control unit configured to control an output rate of a frame to be copied.

Abstract: There is provided an apparatus for performing loop-free transmission in a communication network. The apparatus includes a plurality of ports, a controller, a memory, and an interface unit. The controller generates monitoring frames that are transmitted to another apparatus, so as to monitor a connection state of the communication network. The memory includes port-state information that stores a port state in association with each of the plurality of ports. The interface unit processes a frame based on the port-state information and sets, in the port-state information, a stopped state to a first port included in the plurality of ports, in accordance with a time period during which the monitoring frames are not generated. The interface unit discards a frame received via the first port for which the stopped state is set in the port-state information.

Abstract: A collision detection unit detects whether a first entry that is associated with a value obtained by hashing a first MAC address is present in each area in a MAC address table and detects whether a second entry that is associated with a value obtained by hashing a second MAC address is present in each area in the MAC address table. If the first entry is present in each of the areas, a collision avoidance control unit acquires the second MAC address stored in the first entry that is present in one of the areas and inputs the second MAC address in the collision detection unit. If the second entry is not present in any of the areas in the MAC address table, a registration unit stores the second MAC address in the second entry and stores the first MAC address in the first entry.

Abstract: Transmission equipment includes: a first interface unit configured to receive a frame; and a second interface unit configured to transmit the received frame received by the first interface unit. The second interface unit includes a transmission circuit configured to transmit path information that represents a state of a logical path pair including a work path and a protection path provided for the received frame to the first interface unit. The first interface unit includes a destination determination circuit configured to determine a destination of the received frame based on the state of the logical path pair represented by the path information received from the second interface unit.

Abstract: An apparatus is connected to a Layer 3 network through a gateway and communicates with lower-level devices. The apparatus includes a storage unit that stores information on a port connected to each lower-level device, in association with a group identifier identifying a terminal group including a plurality of terminals under control of each lower-level device. Upon receiving a frame whose destination information includes information specific to the gateway, the apparatus identifies, based on a terminal identifier identifying a terminal that is a destination of a packet within the frame, a group identifier identifying a terminal group to which the terminal belongs, and transfers the frame from a port associated with the group identifier to a lower-level device controlling the terminal group identified by the group identifier so that the lower-level device updates the destination information of the frame by using information specific to the terminal.

Abstract: A communication system includes a first communication device configured to transmit input data to a transmission path, detects a first accumulated amount of the input data, and transmit notifying data to the transmission path when the detected first accumulated amount has reached a threshold value, and a second communication device configured to receive data transmitted to the transmission path by the first communication device, detect a second accumulated amount of the received data, and output measurement information based on the detected second accumulated amount and the threshold value when having received the notifying data.

Abstract: A communication device includes a first memory configured to store transfer information for controlling frame transfer; a processor configured to register a transmission source address of a received frame and corresponding transfer information in the first memory; and a second memory configured to store an upper limit number of registrable addresses for each of designated groups, wherein the processor is configured to determine whether or not the transmission source address of the received frame is registrable in the first memory, based on a result of comparison between a number of registered addresses in a group corresponding to the received frame and an upper limit number assigned to the group corresponding to the received frame.

Abstract: A transmission apparatus includes: a memory; one or more processors coupled to the memory and the one or more processors execute: a first management process that manages a remaining amount of tokens in a token bucket; a second management process that manages an amount of data of a frame transmitted in a predetermined period of time; and a transmission control process that controls transmission of a frame to be transmitted, based on whether the remaining amount of tokens is larger than or equal to an amount of data of the frame to be transmitted and whether the amount of data of the frame transmitted in the predetermined period of time is smaller than a predetermined amount.

Abstract: A transmission device includes: a first counter; a counter control unit configured to increment the first counter at a specified rate; a frame buffer configured to store a received frame; and a buffer control unit configured to read a frame from the frame buffer when a value of the first counter is larger than a specified threshold and output the frame. When a length of an output frame read from the frame buffer by the buffer control unit is shorter than a specified reference frame length, the counter control unit decrements the first counter by a value indicating the reference frame length. When the length of the output frame is longer than or equal to the reference frame length, the counter control unit decrements the first counter by a value indicating the length of the output frame.

Abstract: A reception apparatus includes a receiver configured to receive a packet including a label and quality information indicating communication quality for the packet. The reception apparatus also includes a processor configured to allocate a priority to the received packet based on a combination of the label and the quality information included in the received packet and a transmitter configured to supply the packet to which the priority is allocated to a switch that performs transfer control to a packet based on its priority.

Abstract: A communication device includes a processor that is operative to perform actions, including, determining whether a failure occurs in a regular communication channel to transmit a packet to another communication device, selecting, upon determining that the failure occurs in the regular communication channel, a backup communication channel for transmitting the packet, determining, upon selecting the backup communication channel, whether the backup communication channel is shared by the regular communication channel and another regular communication channel, changing, upon determining that the backup communication channel is shared, a priority assigned to the packet transmitted from the regular communication channel to the backup communication channel, and controlling the transmission of the packet in accordance with the changed priority.

Abstract: There is provided a communication system including a first communication apparatus configured to connect a first path of a first network with a second network, and a second communication apparatus configured to connect a second path of the first network with the second network, wherein the first communication apparatus is configured to notify the second communication apparatus of a status of the first path, and wherein the second communication apparatus is configured to transfer, to the second network, data transferred on the second path, based on the notified status of the first path.

Abstract: A communication control device includes a storage unit configured to store source addresses and destination addresses of one or more frames, a determination unit configured to determine respective access proportions for types of accesses to the storage unit, in accordance with an empty state of the storage unit, the empty state being a proportion of the number of empty entries in the storage unit to the total number of entries, and a control unit configured to control whether to access the storage unit, based on the access proportions determined by the determination unit and proportions for accesses having been made to the storage unit.