Nippon Telegraph and Telephone Corporation

Kiyoshi Matsumoto

Shingo Kawai

Katsumi Iwatsuki

Naoto Yoshimoto

Hideo Kawata

Shinichi Yoshihara

Erina Takeshita

Nobuhiro Shibata

Hideaki Kimura

Yoshitaka Enomoto

Kazuhisa Furusawa

An object is to provide a communication system, a communication method, a transmission-side switching device, a reception-side switching device, and a program that can carry out network switching of a plurality of L2NWs with a short communication disconnection time without limiting topology. A transmission-side accommodation SW duplicates a frame received from a transmission-side user device and transfers the frame to a plurality of L2NWs to which the transmission-side accommodation SW is connected. When receiving a frame from any one of the plurality of L2NWs to which a reception-side accommodation SW is connected, the reception-side accommodation SW transfers, to a reception-side user device, only a frame from one L2NW allowed to transfer a frame to an access accommodation port and discards frames from the other L2NWs. At a switching time of the L2NWs, the reception-side accommodation SW changes the L2NW allowed to transmit a frame to the access accommodation port.

Communication system, communication method, transmitting side switching device, receiving side switching device, and program

An object of the present disclosure is to reduce band compression even in a case where a frame addressed to an original (overwritten) MAC is received again after a MAC address is overwritten. A communication device according to the present disclosure measures a traffic amount in any predetermined determination data unit, holds MAC entry information including the measured traffic amount and a MAC address in a MAC learning data holding unit, at the time when the number of pieces of MAC entry information held by the MAC learning data holding unit reaches an upper limit, searches for minimum MAC entry information with a minimum traffic amount from among traffic data amounts in determination data unit held by the MAC learning data holding unit, and overwrites the minimum MAC entry information obtained by search with unlearned MAC entry information that is not held by the MAC learning data holding unit.

Communication device, address learning method, and program

An object is to provide a monitoring device capable of acquiring ONU-specific information and connection information even in the case of an optical communication system with the MC system, and enabling optical fiber cable switching work to be finished in a short time. The monitoring device according to the present invention is a monitoring device that monitors an optical communication system in which an OLT and an ONU are connected by a communication optical fiber, and includes: an optical receiver for receiving a signal beam transmitted by the ONU from the communication optical fiber; and an OAM frame analysis unit for extracting, from the signal beam received by the optical receiver, an OAM frame at a MEG level at which the ONU and the OLT are set as monitoring end points, and acquiring a transmission source address and a MEG-ID that identifies a MEG in the OAM frame.

Monitoring device

A network design apparatus, a network design method, and a network design processing program design a network configuration for a network in which a transfer apparatus is disposed at each of a plurality of communication hubs, and the communication hubs are connected via a link by a link portion apparatus in the transfer apparatus. In design of the network configuration, the optimal path candidates of each of the lines minimizing a total cost value in the overall network is calculated. In the calculation of the optimal path candidates of each of the lines, only a path candidate of each of the lines can be selected, and a combination candidate of link portion apparatuses for each of the links is derived uniquely from the selected path candidate of each of the lines.

Network design device, network design method, and network design processing program

With a network design apparatus, a network design method, and a network design processing program, a network configuration is designed for a network in which a transfer apparatus is disposed at each of a plurality of communication hubs and the communication hubs are connected via a link by a link portion apparatus in the transfer apparatus. In design of a network configuration, a threshold value of an inter-end delay and the number of redundant paths are calculated for each line on the basis of topology information, line information, and design parameter information. A path candidate set is calculated for each line on the basis of the threshold value of the inter-end delay and the number of redundant paths.

With a network design apparatus, a network design method, and a network design processing program, a network configuration is designed for a network in which a transfer apparatus is disposed at each of a plurality of communication hubs and the communication hubs are connected via a link by a link portion apparatus in the transfer apparatus. In design of a network configuration, an optimal combination candidate of a link portion apparatus for each link for minimizing a total cost value in an overall network is calculated on the basis of a combination candidate set of link portion apparatuses. The combination candidate set of the link portion apparatuses is configured using only combination candidates with a cost-effectiveness indicating a ratio of a total capacity to a total cost value of the link portion apparatus higher than a predetermined reference.

In the present invention, the extremely complicated setting and control and an extremely expensive optical component (wavelength locker) are not required, and optical output wavelength and optical output power can simply be set and controlled at a moderate price. At least one value for determining a dependence of the optical output wavelength on drive current and device temperature and at least one value for determining a dependence of the optical output power on drive current and device temperature in a light emitting device constituting first meansfor emitting light are stored in fourth means. Fifth meansdetermines drive current or optical output power c and device temperature d, at which both the optical output wavelength and optical output power of the light emitting device are separately specified value b, from a relationship among the drive current, device temperature, and optical output wavelength of the light emitting device, the relationship being determined by the at least one value, and a relationship among the drive current, device temperature, and optical output power, the relationship being determined by the at least one value, and the fifth meansgives the drive current or optical output power c and device temperature d as target values to second meansand third means

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Musashino, Japan

Hideo Kawata