Mitsubishi Electric Corporation

Jun Mizuguchi

Yoshifumi Hotta

Kenichi Nakura

Fumihiko Tano

Seiji Kozaki

Takeshi Suehiro

Akiko Iwasaki

Ryuma Matsushita

Koshi Sugimura

A communication system includes a master device, a slave device, and a relay device. The relay device includes a time synchronization management unit that stores retention time of a first time-synchronization frame sent from the master device, adds the first-time-synchronization-frame retention time to a correction field when a second time-synchronization frame sent from the master device is relayed, stores retention time of a third time-synchronization frame sent from the slave device, and adds the third-time-synchronization-frame retention time to a correction field when a fourth time-synchronization frame sent from the master device is relayed. The slave device includes a transmission delay time aggregation unit storing a value in the correction field of the second time-synchronization frame and characteristic information about priority in a frame in association with each other, and storing a value in the correction field of the fourth time-synchronization frame and the characteristic information in association with each other.

Communication system, communication device, communication method, control circuit, and storage medium

A network control device for generating a slice by dividing a network and allocating communication resources to the slice, the slice being a virtual network, the network control device including: a processor; and a memory to store a program which, when executed by the processor, performs processes of: obtaining and holding resource information from a network device included in the network, the resource information including information on a maximum usage rate of communication resources allocated to a previously generated slice in at least one predetermined period; and determining, upon receiving a request for generating a new slice, whether or not the requested slice can be generated on the basis of the resource information held, wherein the resource information includes information on a maximum usage rate of communication resources, which are allocated to the previously generated slice, depending on a request delay concerning the slice in the predetermined period.

Network control device, communication resource allocation method, and communication system

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 communication apparatus (a slave) that performs time synchronization with a master apparatus on the basis of a time synchronization message transmitted from the master apparatus (a master) at a fixed cycle. The communication apparatus (the slave) includes a CPU that stores, in a transmission request message for requesting transmission of the time synchronization message, a requesting transmission rate, and transmits the transmission request message to the communication apparatus (the master). The CPU calculates time synchronization accuracy, which is a difference between time of the master apparatus and time of its own apparatus, on the basis of the time synchronization message; determines on the basis of the time synchronization accuracy whether the requesting transmission rate is changed; and, transmits, if it is determined that the requesting transmission rate is changed, the transmission request message, in which the changed requesting transmission rate is stored, to the communication apparatus (the master).

Communication apparatus, communication system, and time synchronization method

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 ONU includes a CDR that regenerates a clock based on a signal from an OLT, an oscillator that generates an internal clock, a time stamp counter that manages a time of the ONU based on the clock in a period in which the CDR regenerates the clock and manages the time of the ONU based on the internal clock in a period in which the CDR does not regenerate the clock, an MPCP control unit that decides, when a Cyclic Sleep mode is set, a receiver-time synchronization time that is a period in which the receiver is normally operated within a sleep time, based on a difference between a time stamp value included in the signal transmitted from the OLT and a time stamp managed by the time stamp counter, and a power-saving control unit that controls the receiver to be normally operated in the receiver-time synchronization time.

Growing community of inventors

Tokyo, Japan

Jun Mizuguchi