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 apparatus includes a reconfigurable optical add/drop multiplexer (ROADM) having an input port to receive a first optical signal from a second device. The ROADM also includes a first wavelength selective switch (WSS), in optical communication with the input port, to convert the first optical signal into a second optical signal, a loopback, in optical communication with the first WSS, to transmit the second optical signal, and a second WSS, in optical communication with the loopback, to convert the second optical signal to a third optical signal and direct the third optical signal back to the second device via the input port.

Methods and apparatus for providing enhanced optical networking service and performance which are particularly advantageous in terms of low cost and use of existing infrastructure, access control techniques, and components. In the exemplary embodiment, current widespread deployment and associated low cost of Ethernet-based systems are leveraged through use of an Ethernet CSMA/CD MAC in the optical domain on a passive optical network (PON) system. Additionally, local networking services are optionally provided to the network units on the PON since each local receiver can receive signals from all other users. An improved symmetric coupler arrangement provides the foregoing functionality at low cost. The improved system architecture also allows for fiber failure protection which is readily implemented at low cost and with minimal modification.

A method for establishing an embedded optical communication channel in an optical WDM transmission system including: creating, at the central network device, a broad-band optical signal, supplying the broadband optical signal, transmitting the broadband optical signal and the plurality of second optical channel signals to an optical demultiplexer device, transmitting an optical signal consisting of a dedicated second optical channel signal and a filtered broadband optical signal; receiving the optical signal and creating a corresponding electrical receive signal and extracting the electrical signal corresponding to the filtered broadband optical signal from the electrical receive signal and detecting whether the electrical signal contains information intended for the respective first channel transceiver.

Embodiments of this application provide a service protection method, including: A first node determines that a fault occurs on a first working path; the first node generates a bandwidth activation message based on the fault, where the bandwidth activation message indicates a third node to adjust a bandwidth of a service from a protection bandwidth to a target bandwidth, the protection bandwidth represents a pre-occupied bandwidth of a first protection path before transmission of the service, and the target bandwidth represents an actual occupied bandwidth for transmission of the service; and the first node sends the bandwidth activation message on the first protection path.

Systems and methods for logical to physical link mapping in a fiber optic network are provided. In one implementation, a method includes receiving geographic data related to one or more fiber links in a fiber optic network; receiving logical links on the one or more fiber links; receiving results from one or more tests performed on the one or more fiber links; utilizing the results to determine a physical representation of the one or more fiber links; and displaying a network map of the fiber optic network with the physical representation.

In one embodiment, systems and method for detecting the intent of a connected optics/cable to operate in either a breakout mode or a non-breakout mode are provided. When a optics/cable is used to connect a port of a spine node to ports of one or more leaf nodes, initially both the spine node and the leaf nodes may automatically configure themselves to operate in breakout mode depending on the optics. Later, the spine node and one or more more leaf nodes may exchange speed and optics information using a link layer discovery protocol or another protocol. If the exchanged speed and optics information indicates a mismatch, then the spine node or the leaf node may retain the breakout mode. If the exchanged speed and optic information do not indicate a mismatch, then the spine nodes and the leaf nodes may automatically re-configure themselves in non-breakout mode.

A transmission device includes a wavelength multiplexer that wavelength-multiplexes a plurality of optical signals having different wavelengths to generate a wavelength-multiplexed optical signal, an amplifier that outputs the wavelength-multiplexed optical signal to a transmission path, and a first processor that allocates wavelength bands to the plurality of optical signals to be wavelength-multiplexed into the wavelength-multiplexed optical signal and controls power of the wavelength-multiplexed optical signal in accordance with the wavelength bands allocated to the plurality of optical signals.

A node device capable of optimal transfer in accordance with the traffic situation of a network irrespective of the optical signaling system is provided. The node device includes a first wavelength selective switch connected to an input-side optical fiber; a fast selective switch connected to the first wavelength selective switch for cut-through or selective switching to an OCS controller or an OFS/OPS controller; an optical coupler connected to a cut-through output of the fast selective switch, an output of the OCS controller, and an output of the OFS/OPS controller; a second wavelength selective switch connected to an output of the optical coupler; and a node controller that performs wavelength assignment control for the first and second wavelength selective switches, path/label switch control for the fast selective switch, and flow/packet switch control for the OFS/OPS controller.

In one embodiment, a method includes receiving, by a network controller and from a first node of a network, information associated with a data stream of the network and determining, by the network controller, a segmentation for the data stream. The segmentation includes a plurality of data segments and the plurality of data segments includes a first data segment. The method further includes determining, by the network controller, a data flow path for each of the plurality of data segments and determining, by the network controller, a first wavelength to assign to the first data segment. The first wavelength is one of a plurality of wavelengths spanning between the first node and a second node of the network.