Mitsubishi Electric Corporation

Yoshifumi Hotta

Masaki Tanaka

Ryuma Matsushita

Jun Mizuguchi

Seiji Kozaki

Sachiko Taniguchi

Hiroaki Mukai

Kenichi Nakura

Ryusuke Kawate

Koshi Sugimura

Kaori Mie

Makoto Kubomi

Daisuke Takita

A time-point synchronization apparatus () includes a time-point management unit (), a time-gap counter (), and a time-gap calculation unit (). The time-point management unit () manages an apparatus time point equivalent to a current time point. The time-gap counter () records a time gap which is a different between a time point indicated in reception information and the apparatus time point. When a frequency in the time-gap counter (), corresponding to the time gap corresponding to a latest reception time point corresponding to latest reception information is treated as the highest among all of frequencies indicated in the time-gap counter (), the time-gap calculation unit () synchronizes the apparatus time point to the latest reception time point.

Time-point synchronization apparatus, time-point synchronization method, and non-transitory computer readable medium

A reception unit () receives an addition requesting frame for requesting addition of a new flow. A first search unit () performs, using a network-information database (), a first search for searching for a schedule and a path assignable to the new flow without the schedule and the path of each existing flow being changed, when the addition requesting frame is received. A second search unit () performs a second search for changing the schedule and the path of each existing flow and searching for the schedule and the path assignable to the new flow, using the network-information database, when the schedule and the path assignable to the new flow have not been found by the first search. A response unit () transmits an addition responding frame.

Controller, network system, and flow management method

An information obtaining unit () of a monitoring apparatus () obtains from each node, topology map information created in each node by an exchange of information and sharing of information between nodes that belong to a ring network. The topology map information is information that indicates a connection relation between the nodes in the ring network. A topology comparison unit () of the monitoring apparatus () compares the topology map information obtained from each node by the information obtaining unit () with topology definition information retained in a memory () beforehand, and determines whether or not a configuration of the ring network is according to design. The topology definition information is information that defines the connection relation between the nodes in the ring network.

Monitoring apparatus, network system, topology management method, and computer readable medium

Provided are a redundant route calculator that calculates, on the basis of first topology information on a network made up of a plurality of transfer devices, a plurality of shortest routes from a first transfer device to a second transfer device among the plurality of transfer devices, and generates redundant route information; a forwarding database that stores the redundant route information; and a single point-of-failure detector that detects a single point of failure on the basis of the redundant route information and generates second topology information obtained by removing the single point of failure from the first topology information. On the basis of the second topology information, the redundant route calculator calculates an additional route candidate from the first transfer device to the second transfer device. The single point-of-failure detector decides the additional route to register in the forwarding database.

Transfer device and route addition method

A transfer device according to the present invention is a switching device that is one of transfer devices forming a network, and includes: a link state database that holds topology information of the network, and priority of the transfer device and priorities of other transfer devices forming the network to be used in path computation; a shortest path calculating unit that calculates a shortest path from a first switching device to a second switching device among the transfer devices forming the network on the basis of the topology information; and a priority adjusting unit that adjusts the priority of the transfer device on the basis of the shortest path calculated by the shortest path calculating unit and the priority of the transfer device and the priorities of the other transfer devices, wherein the priority adjusting unit adjusts the priority of the transfer device so that the number of overlaps with priority of another transfer device that is included with the transfer device in a shortest path from one start point to one destination and at the same distance from the start point as the transfer device is reduced.

Transfer device, adjustment device, and parameter adjusting method

A time synchronization method for a communication system configured to perform protection switching, the communication system including a first network in which a master station and a slave station are connected via plural physical lines including a working line and a backup line and a second network connected to the slave station, the method including a time synchronization in which the slave station executes, when not detecting a communication failure of a downlink signal transmitted from the master station, synchronization processing for synchronizing, based on a clock of the slave station and timing information, time information transmitted to the second network with time information included in a time synchronization command and suppresses, when detecting a communication failure or receiving a switching notification from the master station apparatus, a synchronization error due to a difference between the clock of the slave station and the timing information.

Time synchronization method for communication system, slave station apparatus, master station apparatus, control device, and program

A relay device that relays communication between a low-speed communication device performing uplink 1 G transfer and a high-speed communication device performing uplink 10 G transfer and a station-side optical communication device, wherein the relay device includes a low-speed reception unit that converts an optical signal received from the low-speed communication device to an electric signal, a buffer that buffers the electric signal, and a high-speed transmission unit that transmits, to the station-side optical communication device, a bandwidth allocation request requesting bandwidth allocation for communication from its own unit to the station-side optical communication device, and within a transmission permitted time period allocated by the station-side optical communication device, reads an electric signal stored in the buffer, converts the electric signal to an optical signal having a communication speed of 10 G, and transmits the optical signal.

Relay device, station-side optical communication device, communication system, and bandwidth allocation method

An optical line terminal performs transmission to optical network units using a light signal having a wavelength different for each of systems, allocates communication time to data, which is transmitted from the optical network units, in a time division manner for each of the systems, selects, for each of the optical network units, a system for performing data transmission, and transmits the data using a wavelength corresponding to the selected system. The optical network unit includes: ith blocking filter that removes a component other than a component in a predetermined wavelength band, which is set to correspond to an ith system, from a received light signal; and ith PON processing unit that applies termination processing to signals and transmitting the data based on an allocation result of the optical line terminal. The PON system includes n optical network units corresponding to i=1 to i=n.

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Tokyo, Japan

Yoshifumi Hotta