Embodiments of the present disclosure relate to methods, optical line terminals (OLTs), optical network units (ONUs), apparatuses and computer storage media for transmitting a time synchronization message. In some example embodiments, the OLT is configured to: determine a threshold rate to be N messages per second for transmission of a time synchronization message to an ONU, wherein N being greater than or equal to 0.1; and transmit, to the ONU, a time synchronization message at the threshold rate or a rate above the threshold rate, to enable the ONU to perform time synchronization with the OLT. In some other example embodiments, the OLT is configured to: select a plurality of ONUs for transmitting time synchronization information; and transmit, to the ONUs, a broadcast or multicast message the time synchronization information, to enable the plurality of ONUs to perform time synchronization with the OLT.

An optical device may include a communication interface and processing logic configured to receive a broadcast contention-based allocation from an optical line terminal (OLT), wherein the contention-based allocation is associated with activation of the optical device in an optical network. The processing logic may also be configured to transmit a message in response to the contention-based allocation, wherein the message includes information identifying the optical device and receive, from the OLT, an assignment message or a feedback message in response to the transmitted message. The processing logic may be further configured to execute a retransmission procedure based on the assignment or feedback message indicating that a collision occurred.

Aspects of the subject disclosure may include, for example, receiving a first optical signal from a first optical network via a first port of the wavelength converter, receiving a second optical signal from a second optical network via a second port of the wavelength converter, modulating the first optical signal with the second light signal to generate a third optical signal, eliminating the first light signal from the third optical signal to generate a fourth optical signal, and transmitting the fourth optical signal through the second optical network. The first optical signal can include a first digital signal modulated onto a first light signal of a first wavelength, the second optical signal can include a second light signal can include a second wavelength different from the first wavelength, and the fourth optical signal can include the first digital signal modulated onto the second light signal. Other embodiments are disclosed.

The present application provides a data transmitting method, a data transmitting apparatus, a data receiving method, a data receiving apparatus, a communication node and a storage medium. The data transmitting apparatus includes: converting a data frame to be transmitted into a data frame group; encapsulating the data frame group to obtain an encapsulated frame; and transmitting the encapsulated frame.

A data transmission method includes receiving, by an optical line terminal (OLT) from an optical network unit (ONU), uplink burst data that includes a synchronization data block and a payload, where the synchronization data block includes first synchronization data, wherein the first synchronization data includes a first preamble and an ONU identifier, and a first bandwidth occupied by the first frequency distribution of the first synchronization data is narrower than a second bandwidth occupied by the second frequency distribution of the payload, and obtaining, by the OLT from the first synchronization data, the ONU identifier.

A data transmission method includes receiving, by an optical line terminal (OLT) from an optical network unit (ONU), uplink burst data that includes a synchronization data block and a payload, where the synchronization data block includes first synchronization data, wherein the first synchronization data includes a first preamble and an ONU identifier, and a first bandwidth occupied by the first frequency distribution of the first synchronization data is narrower than a second bandwidth occupied by the second frequency distribution of the payload, and obtaining, by the OLT from the first synchronization data, the ONU identifier.

This application provides example methods for establishing a service path in a transport network and example systems. One example method includes, obtaining, by an automatically switched optical network (ASON) first node, a service path computation result path. The service path includes the ASON first node, an ASON last node, and at least one first edge network node. The method also includes sending, by the ASON first node, a path establishment request message to a downstream node. The path establishment request message carries cross-connection configuration information of the ASON last node and the at least one first edge network node. The method further includes receiving, by the ASON first node, a path establishment response message of the downstream node. The path establishment response message indicates that cross-connection configuration for the ASON last node and the at least one first edge network node is complete.

An optical routing system for free space optical communication is disclosed. The system has a transmitter and a receiver that use free space optical communication, and includes an optical path based on waveguide where an optical signal is routed from the proximity of the transmitter to the proximity of the destination. This system has advantages in terms of mitigating line-of-sight issues, as well as potentially reducing the overall coupling loss that would be otherwise incurred due to beam divergence of free space propagation for long distance.

A method for channel management in an optical network unit includes receiving a disable channel action message sent by an optical line terminal, wherein the disable channel action message is used to instruct disabling a first channel of the optical network unit; transferring the state machine of the optical network unit on the first channel from the association substate of the operation state to the pending substate according to the disable channel action message; and turning off the transmitter and/or the receiver on the first channel after a specified time is reached, transferring the state machine from the pending substate of the operation state to the disabling channel status, and starting a timer.

A communication device includes: a first transmission-reception unit connected with a first optical line terminal; a second transmission-reception unit connected with a second optical line terminal; and a control unit, the first transmission-reception unit acquires a control signal having a destination at the second or third optical line terminal from the first optical line terminal, the control unit forwards the control signal toward the second transmission-reception unit connected with the second or third optical line terminal, and the second transmission-reception unit forwards the control signal to the second or third optical line terminal.