A transmission device for which a work path is established in a first degree and a protection path is established in a second degree includes: a switch equipped with a plurality of optical ports; an optical signal generator, optically connected to a first optical port, and configured to generate an optical signal that is transmitted through the work path; and a monitor light generator, optically connected to a second optical port, and configured to generate monitor light by using a wavelength tunable light source. The monitor light generator controls a wavelength of the monitor light to be substantially the same as a wavelength of the optical signal. The switch guides the optical signal that arrives at the first optical port toward the first degree and guides the monitor light that arrives at the second optical port toward the second degree.

A node (20, 25) for a single fiber bidirectional WDM optical ring network has a first optical protection switch (100) having first and second ports for coupling to the single fiber bidirectional ring, while providing a pass through optical path for wavelengths on the bidirectional ring. A further port is coupled to an external optical path. In operation the switch couples optically bidirectional selected wavelengths between the external optical path and either of the first and second ports selectively, according to an indication of a fault on the ring, so as to use different portions of the bidirectional ring respectively as working path and protection path. This combines coupling wavelengths with the ring, with the selection of protection or working path, which simplifies the optical equipment, and upstream and downstream optical delays can be symmetrical.

A network device in a RPR network receives a RPR flooding data packet sent by another network device in the RPR network, determines whether a next-hop network device of the RPR flooding data packet is a source network device sending the RPR flooding data packet, and strips the RPR flooding data packet when determining that the next-hop network device of the RPR flooding data packet is the source network device sending the RPR flooding data packet.

Optical protection switching apparatus (10), for a single fibre bidirectional WDM optical ring, comprising: first (12) and second (14) ports for coupling to first and second adjacent portions of a single fibre bidirectional WDM optical ring; an optical splitter (16) comprising an input to receive a WDM aggregate optical signal, and first and second outputs coupled to the first and second ports; an optical switch (108) between the second output and the second port; and processing circuitry (24) to receive at least one of an indication of transmission continuity in the optical ring and an indication of transmission discontinuity in the optical ring, and to generate a switch control signal (20) comprising instructions to cause the optical switch to be open when there is transmission continuity in the optical ring and to cause the optical switch to be closed when there is transmission discontinuity in the optical ring.

A method for assigning a severity to failure indications of network resources in a multilayered communication network includes in a processor, receiving one or a plurality of failure indications related to a failure of one or more network resources from a plurality of network resources in a communication network. A severity may be assigned to the one or said plurality of failure indications based on an impact on data, wherein assigning the severity includes at least one of: assigning a static severity based on a single traffic impact assessment in the communication network due to the one or more failed network resources, and assigning a dynamic severity based on continuous or periodic traffic impact assessments in the communication network due to the one or more failed network resources. The severity of the one or said plurality of failure indications may be outputted on an output device.

A high-density networking system includes first networking device(s) coupled to a second networking device. The second networking device has a port row including first ports and a first subset of third ports, and second ports and a second subset of third ports that are each moveable relative to the first ports and the first subset of third ports, with the third ports coupled to the first networking device(s). The second networking device includes a switch device coupling the third ports to its processing system. The switch device in second networking device routes data from the processing system through a network via the first subset of third ports/first networking device(s), determines that data received from the processing system cannot reach the network via the first subset of third ports and, in response, routes data received from the processing system through the network via the second subset of third ports/first networking device(s).

This disclosure describes devices and methods related to multiplexing optical datasignals. A method may be disclosed. The method may comprise receiving, by a dense wave division multiplexer (DWDM), one or more optical data signals. The method may comprise combining, by the DWDM, the one or more optical data signals. The method may comprise outputting, by the DWDM, the combined one or more optical data signals to a first circulator. The method may also comprise combining, by the WDM, the second optical data signal and one or more third signals, and outputting an egress optical data signal to an optical switch. The method may also comprise outputting, by the optical switch, the egress optical data signal on a primary fiber.

An optical network having a first terminal node, a second terminal node, and a network service system is described. The first terminal node has a plurality of ports and a signal restoration component to create a restored path. The second terminal node has a plurality of ports and a failure monitor to issue a path failure notice. A working path, a protection path, and the restored path are each fiber optic lines optically coupling the first terminal node to the second terminal node to enable a service, each path requiring a quantity of exclusive licenses. The network service system receives a path failure notice indicating a working path failure, calculates the quantity of licenses required by the restored path, releases the quantity of licenses required by the working path and applies at least a portion of the quantity of licenses to the quantity of licenses required by the restored path.

Systems and methods for controlling network configurations or assignments are provided. A method, according to one implementation, includes a step of calculating transmission characteristics between each pair of a plurality of pairs of modems at opposite ends of a Dense Wavelength-Division Multiplexing (DWDM) transport link using specifications of the modems measured during production. The method also includes the step of selecting a pair of modems from the plurality of pairs of modems based on results obtained by calculating the transmission characteristics and based on one or more user-defined service requests.

Provided are a communication station, an optical communication system, a data transmission method, and a storage medium. The communication station is a first station including: a first reconfigurable optical add-drop multiplexing ROADM device, including a first port used to connect a cable in a first direction of a network; a second ROADM device connected to the first ROADM device and including a second port which may be used to connect a cable in a second direction of the network being different from the first direction; an optical protection device connected to each of the first and second ROADM devices and used to control the first station to transmit communication with a second station for a corresponding service in the first direction corresponding to the first ROADM device, or to transmit communication with the second station for a corresponding service in the second direction corresponding to the second ROADM device.