An optical interface includes circuitry configured to operate the optical interface at a first rate, subsequent to a requirement to subrate the optical interface to a second rate, determine which services are affected, signal a partial failure for the one or more affected services, and operate the optical interface at a second rate that is less than the first rate. The optical interface can be a Flexible Optical (FlexO) or ZR interface.

Systems and methods include receiving (102) a plurality of symbols that are part of a defined Digital Signal Processing (DSP) frame for coherent optical communication, wherein the DSP frame structure has a messaging channel incorporated therein that includes a subset of the plurality of symbols; capturing (104) multiple samples of the messaging channel; and determining (106) a message in the messaging channel based on analysis of the multiple samples. The method can further include transmitting (108), in the messaging channel, a reply to the message with the reply being repeated multiple times. The analysis is performed prior to Forward Error Correction (FEC) decoding on the data path.

Systems and methods are implemented at an Optical Add/Drop Multiplexer (OADM) node using virtual sections to provide sectional control over an optical link over a foreign-controlled optical network. The systems and methods include virtually splitting the optical link at a shelf processor associated with the OADM node; in a non-fault condition, obtaining and storing a power snapshot of the optical link and associated virtual sections thereon, from an optical spectrum monitor; responsive to a fault on one or more virtual sections of the virtual sections, obtaining a current power snapshot of the optical link and the associated virtual sections; and comparing the stored power snapshot and the current power snapshot of the one or more virtual sections and providing a fault alarm for the one or more virtual sections based on the comparing to a control plane for management thereof.

Systems and methods of coordinating Layer 1 and Layer 2 protection switching include, at a node having a plurality of ports including a first port that is an endpoint of a Layer 1 network and a second port that connects to a Layer 2 network, communicating defects in the Layer 1 network to a local Maintenance End Point (MEP) on the second port and any recovery actions being performed in the Layer 1 network; informing other nodes on the Layer 2 network via the second port of the defects and the recovery actions; and coordinating Layer 2 protection switching in the Layer 2 network based on the defects and based on the recovery actions in the Layer 1 network.

Systems and methods are in a node in a network utilizing a control plane for triggering mesh restoration due to intra-node faults, and include monitoring at least one channel at a degree at a plurality of degrees associated with the node; detecting a fault on the at least one channel, wherein the fault is an intra-node fault upstream of the degree; and transmitting a channel fault indicator downstream of the fault to at least one downstream node along a path of the faulted channel, wherein restoration is triggered based on the channel fault indicator.

An optical modem includes client interface circuitry; line interface circuitry configured to interface a client signal with the client interface circuitry and interface a line signal in a transmit direction and a receive direction, wherein the line signal terminates at a second optical modem; and a clock connected to the line interface circuitry, wherein the clock includes a selector configured to select one of a local reference clock and a recovered clock from the receive direction based on whether the optical modem is a master or slave and based on whether there is a fault in the receive direction, wherein the optical modem and the second optical modem form a timing island separate from a timing domain associated with the client signal and a second client signal associated with the second optical modem.

The present disclosure discloses a protection switching method and a node. The method includes: receiving, by an intermediate node, a first protection switching request message sent by an upstream neighboring node, where the first protection switching request message is used to request to activate a first protection path, and the intermediate node is a node on the first protection path; determining, by the intermediate node, that the first protection path needs to occupy N1 timeslots, and selecting N1 timeslots for the first protection path from N2 available timeslots in a preset order; and sending, by the intermediate node, a second protection switching request message to the downstream neighboring node, where the second protection switching request message is used to request the downstream neighboring node to complete a cross-connection, on the first protection path, between the downstream neighboring node and the intermediate node based on the first group of timeslots.

Systems and methods of end-to-end data path integrity validation of a service with a data path at Layer 1 and Layer 2 implemented by a network element include, responsive to initiation of a test, messaging between network elements in the data path to coordinate defect and statistics collection at each of the network elements in the data path; receiving results for the defect and statistics collection from each of the network elements in the data path; and summarizing the received results to form a consolidated report for the test across all of the network elements in the data path.

Systems and methods are implemented at an Optical Add/Drop Multiplexer (OADM) node using virtual sections to provide sectional control over an optical link over a foreign-controlled optical network. The systems and methods include virtually splitting the optical link at a shelf processor associated with the OADM node; in a non-fault condition, obtaining and storing a power snapshot of the optical link and associated virtual sections thereon, from an optical spectrum monitor; responsive to a fault on one or more virtual sections of the virtual sections, obtaining a current power snapshot of the optical link and the associated virtual sections; and comparing the stored power snapshot and the current power snapshot of the one or more virtual sections and providing a fault alarm for the one or more virtual sections based on the comparing to a control plane for management thereof.

In the optical transport system a transport frame generator divides a transport frame accommodating plural client signals into plural transmission signals. Subcarrier transmission units convert the signals into optical signals using different optical carriers and transmit the converted optical signals. Subcarrier reception units receive the transmitted optical signals and convert the optical signals into reception signals. A transport frame termination unit combines the reception signals to restore the transport frame. A time-demultiplexing processor time-demultiplexes the restored transport frame to be separated into the client signals. A time slot control unit determines a new time slot allocation when time-multiplexing the client signals in the transport frame and stops supply of electric power to a subcarrier transmission unit and a subcarrier reception unit that transmit and receive an optical signal to which the client signals are not allocated.