Optical interface device, and abnormality monitoring method for input frequency deviation
AssigneeFujitsu Limited
InventorSunao ITOU
Life of this patent
Estimating the term…
Abstract
An optical interface device determines whether frequency deviation of a clock signal corresponding to an optical signal from a client side is abnormal based on a stuff amount when subjecting a data signal corresponding to an optical signal input from the client side to a stuffing process, inserts an alarm indication signal (AIS) indicating that the frequency deviation is abnormal into a predetermined region of a data signal when the deviation is determined to be abnormal, and outputs an optical signal generated corresponding to the data signal to a WDM line side so as to transfer the AIS to another component disposed downstream therefrom, so that locating a site where an abnormal state occurs is made easier.
Claims12
An optical interface device for converting a first optical signal that is received from a first optical transmission line to a second optical signal that can be transmitted through a second optical transmission line which is different from the first optical transmission line, the optical interface device comprising:
- an optical receiver configured to receive the first optical signal, and configured to recover a first data signal and a first clock signal corresponding to the first optical signal;
- a clock generator configured to generate a second clock signal corresponding to the second optical signal;
- a frequency difference detector configured to detect a frequency difference between the first clock signal and the second clock signal, and configured to generate information regarding a stuff amount for a stuffing process to be applied to the first data signal for compensating for the difference;
- a stuffing circuit configured to subject the first data signal to a stuffing process based on the information generated by the frequency difference detector according to timing of the second clock signal;
- a determination circuit configured to determine whether a frequency deviation of the first clock signal is abnormal based on the information generated by the frequency difference detector;
- an alarm generator configured to receive a data signal from the stuffing circuit, and configured to generate an alarm indication signal indicating that the frequency deviation is abnormal to another component that is disposed downstream therefrom through the second optical transmission line when the determination circuit determines abnormal frequency deviation, to thereby insert the alarm indication signal in a predetermined region of the data signal;
- a converter configured to convert the data signal passed through the alarm generator to a second data signal having a frame structure that is compatible with the second optical signal;
- and
- an optical transmitter configured to modulate light according to the second data signal, to thereby generate the second optical signal.
A method for monitoring abnormal frequency deviation of a first optical signal in an optical interface device, the optical interface device converting a first optical signal that is received from a first optical transmission line to a second optical signal that can be transmitted through a second optical transmission line which is different from the first optical transmission line, the method comprising:
- receiving the first optical signal, and recovering a first data signal and a first clock signal corresponding to the first optical signal;
- generating a second clock signal corresponding to the second optical signal;
- detecting difference between the first clock signal and the second clock signal;
- generating information regarding a stuff amount in a stuffing process that is subjected to the first data signal for compensating for the detected frequency difference;
- subjecting the first data signal to a stuffing process based on the information regarding the stuff amount according to timing of the second clock signal;
- determine whether frequency deviation of the first clock signal is abnormal based on the information regarding the stuff amount;
- generating an alarm indication signal indicating that the frequency deviation is abnormal to another component that is connected downstream therefrom through the second optical transmission line when the frequency deviation is determined to be abnormal;
- inserting the alarm indication signal to a predetermined region in a data signal subjected to the stuff process;
- converting the data signal into which the alarm indication signal is inserted to a second data signal having a frame structure that is compatible with the second optical signal;
- and
- modulating light according to the second data signal, to thereby generate the second light signal.
Dependencies are inferred from the claim text.