Abstract: Methods and arrangements for time distribution in an optical network system in the upstream direction. The information of a selected time reference frame and a calculated time stamp value of the frame based on a real-time clock of the optical line terminal (OLT) is sent from the OLT to the optical network unit (ONU) via the optical distribution network (ODN). When the time reference frame is sent to the ONU from the OLT via the ODN, the ONU records the arrival time of the frame based on a time reference made by the real-time clock of the ONU. The time difference between the arrival time and the time stamp value is calculated whereupon the OLT is informed of the calculated time difference. The OLT adjusts the real-time clock of the OLT in accordance with the time difference.

Abstract: Methods and arrangements for time distribution in an optical network system in the upstream direction. The information of a selected time reference frame and a calculated time stamp value of the frame based on a real-time clock of the optical line terminal (OLT) is sent from the OLT to the optical network unit (ONU) via the optical distribution network (ODN). When the time reference frame is sent to the ONU from the OLT via the ODN, the ONU records the arrival time of the frame based on a time reference made by the real-time clock of the ONU. The time difference between the arrival time and the time stamp value is calculated whereupon the OLT is informed of the calculated time difference. The OLT adjusts the real-time clock of the OLT in accordance with the time difference.

Abstract: A method for data-flow protection of an optical interface in data communication equipment includes: receiving an optical-signal from a source-neighboring device, then duplicating the received optical signal into two duplicated optical signals. One of the optical signals is sent to a protected device for processing. According to the protected device working status, either the optical signal having been processed by the protected device or the second duplicated optical signal is selected and sent to a destination-neighboring device. The device includes a first optical-signal duplicating unit and an optical-signal selecting unit. The first optical-signal duplicating unit is used for duplicating an optical signal, and the optical-signal selecting unit is used as a selector. The method and device proposed by the disclosure are independent to network topology and can protect data-flow reliably.

Abstract: A method for data-flow protection of an optical interface in data communication equipment includes: receiving an optical-signal from a source-neighboring device, then duplicating the received optical signal into two duplicated optical signals. One of the optical signals is sent to a protected device for processing. According to the protected device working status, either the optical signal having been processed by the protected device or the second duplicated optical signal is selected and sent to a destination-neighboring device. The device includes a first optical-signal duplicating unit and an optical-signal selecting unit. The first optical-signal duplicating unit is used for duplicating an optical signal, and the optical-signal selecting unit is used as a selector. The method and device proposed by the disclosure are independent to network topology and can protect data-flow reliably.

Abstract: The invention discloses a method and device for data-flow protection of an optical interface in data communication equipment. First, receiving an optical-signal from a source-neighboring device, then duplicating the received optical signal into two duplicated optical signals. One of them is sent to a protected device for processing. According to the protected device working status, either the optical signal having been processed by the protected device or the second duplicated optical signal is selected and sent to a destination-neighboring device. The device of the invention includes a first optical-signal duplicating unit and an optical-signal selecting unit. The first optical-signal duplicating unit is used for duplicating an optical signal, and the optical-signal selecting unit is used as a selector. The method and device proposed by the invention are independent to network topology and can protect data-flow reliably.