Optical crossconnect apparatus

Abstract

In working path setting, a backup path is previously prepared assuming a link failure, and a demultiplexer of a bypass link is connected to a wavelength conversion repeater through an optical switch. Upon occurrence of a link failure, the wavelength conversion repeater is connected to a multiplexer of the bypass link by means of the optical switch to forward an in-channel control signal to the wavelength conversion repeater of an adjacent node where the in-channel control signal is sequentially forwarded to reserve a backup bandwidth. Then, output wavelengths and targets are exchanged between a wavelength tunable transponder and the wavelength tunable repeater.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will now be described in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating the general configuration of an optical crossconnect apparatus and a network management apparatus;

FIG. 2 is a block diagram illustrating the detailed configuration of a wavelength tunable transponder of the optical crossconnect apparatus;

FIG. 3 is a block diagram illustrating the detailed configuration of a wavelength tunable repeater of the optical crossconnect apparatus;

FIG. 4 is a block diagram illustrating the detailed configuration of a monitoring controller of the optical crossconnect apparatus;

FIG. 5 is a block diagram illustrating the detailed configuration of a network management apparatus of the optical crossconnect apparatus;

FIG. 6 is an operation flowchart of the optical crossconnect apparatus and the network management apparatus;

FIG. 7 is a view illustrating the route of an optical path in the normal condition;

FIG. 8 is a view illustrating the route of the optical path when a link failure occurs;

FIG. 9 is a block diagram illustrating an operation of the optical crossconnect apparatus;

FIG. 10 is a sequence diagram illustrating an operation of a backup path pre-health confirmation;

FIGS. 11A to 11C are diagrams showing path tables stored in route-wavelength management information DBs of respective nodes;

FIG. 12 is a timing diagram illustrating the time allocation for the backup path pre-health confirmation;

FIG. 13 is a sequence diagram illustrating a restoration operation;

FIG. 14 is a block diagram illustrating an operation of the optical crossconnect apparatus;

FIGS. 15A to 15B are diagrams showing path tables (bandwidth reservation) stored in the route-wavelength management information of the respective nodes;

FIG. 16 is a block diagram illustrating an operation of the optical crossconnect apparatus;

FIGS. 17A and 17B are diagrams showing path tables (exchange) stored in the route-wavelength management information of the respective nodes; and

FIG. 18 is a sequence diagram illustrating a switchback operation.

Claims

1. An optical crossconnect apparatus comprising: a demultiplexer for demultiplexing a wavelength multiplexed optical signal from a first transmission line;a wavelength tunable transponder for transmitting and receiving an optical signal with a client, wherein the wavelength of the optical signal to be transmitted to an optical switch is tunable;a wavelength tunable repeater for extracting and forwarding an in-channel monitoring control signal, wherein the wavelength of the optical signal to be transmitted to said optical switch is tunable;a multiplexer for wavelength-multiplexing the optical signal and transmitting the multiplexed signal to a second transmission line;said optical switch having the output of said demultiplexer and said transponder and said wavelength tunable repeater as an input, and having the input of said multiplexer and said transponder and said wavelength tunable repeater as an output; anda monitoring controller for transmitting and receiving the in-channel control signal with said wavelength tunable transponder and said wavelength tunable repeater, controlling transmission wavelengths of wavelength tunable transmitters of said wavelength tunable transponder and said wavelength tunable repeater, and controlling connection of said optical switch.

2. An optical crossconnect apparatus comprising: a demultiplexer for demultiplexing a wavelength multiplexed optical signal from a first transmission line;a plurality of wavelength tunable repeaters for extracting and forwarding an in-channel monitoring control signal;a multiplexer for wavelength-multiplexing the optical signal and transmitting the multiplexed signal to a second transmission line;an optical switch having the output of said demultiplexer and said wavelength tunable repeaters as an input, and having the input of said multiplexer and said wavelength tunable repeaters as an output; anda monitoring controller for transmitting and receiving the in-channel control signal with said wavelength tunable repeaters, controlling transmission wavelengths of wavelength tunable transmitters of said wavelength tunable repeaters, and controlling connection of said optical switch,wherein a plurality of inputs of said optical switch to which said plurality of wavelength tunable repeaters are connected are connected to one output of said optical switch in a time division manner.

3. An optical crossconnect apparatus comprising: a demultiplexer for demultiplexing a wavelength multiplexed optical signal from a first transmission line;a wavelength tunable repeater for extracting and forwarding an in-channel monitoring control signal;a multiplexer for wavelength-multiplexing the optical signal and transmitting the multiplexed signal to a second transmission line;an optical switch having the output of said demultiplexer and said wavelength tunable repeater as an input, and having the input of said multiplexer and said wavelength tunable repeater as an output; anda monitoring controller for transmitting and receiving the in-channel control signal with said wavelength tunable repeater, controlling transmission wavelength of a wavelength tunable transmitter of said wavelength tunable repeater, and controlling connection of said optical switch,wherein the input of said optical switch to which said wavelength tunable repeater is connected is connected to a plurality of outputs of said optical switch in a time division manner.

4. The optical crossconnect apparatus according to claim 2 or claim 3, wherein the transmission wavelength of said wavelength tunable repeater is changed in synchronizing with said time division.

5. An optical crossconnect apparatus comprising: an optical switch;a wavelength tunable transponder for accommodating a client signal;a wavelength tunable repeater; anda monitoring controller for performing crossconnect control of said optical switch, transmission wavelength control between said transponder and said wavelength tunable repeater, and transmission and reception of an in-channel control signal,wherein upon occurrence of a failure, the optical crossconnect apparatus exchanges the transmission wavelengths and targets of said optical switch between said wavelength tunable transponder and said wavelength tunable repeater.

6. An optical crossconnect apparatus comprising: an optical switch;a wavelength tunable transponder for accommodating a client signal;a wavelength tunable repeater; anda monitoring controller for performing crossconnect control of said optical switch, transmission wavelength control between said transponder and said wavelength tunable repeater, and transmission and reception of an in-channel control signal,wherein in a switchback operation, said optical crossconnect apparatus exchanges transmission wavelengths and targets of said optical switch between said wavelength tunable transponder and said wavelength tunable repeater.

7. The optical crossconnect apparatus according to claim 5 or claim 6, wherein said apparatus confirms the health of non-working paths by transmitting and receiving said in-channel control signal.