A wavelength multiplexing communication system includes a master station apparatus and a plurality of slave station apparatuses. The master station apparatus includes a wavelength multiplexing communication unit. The wavelength multiplexing communication unit performs wavelength multiplexing communication with the plurality of slave station apparatuses by using optical signals having the number of wavelengths equal to or less than the number of the plurality of slave station apparatuses. The slave station apparatus includes an optical communication unit. When the main signal communication is performed in the host slave station apparatus, the optical communication unit communicates with the master station apparatus by an optical signal having the same wavelength as a wavelength used by another slave station apparatus in which a main signal notification is not performed.

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 communications network comprises optical data links interconnected by add-drop nodes, the optical data links comprising data channels. The data channels are allocated into equal-sized bins. In response to a first data channel request between a given source-destination pair, one of the equal-sized bins is assigned to the data channel request. In response to requests for additional bandwidth for the same source-destination data channel request, unused channels within the assigned equal-sized bin are allocated to the data channel request. In response to subsequent data channel requests between different source-destination pairs, additional unallocated equal-sized bins are assigned to the subsequent data channel requests. In response to subsequent data channel requests when resource sharing for one equal-sized bin, data channels in the last equal-sized bin are assigned using the reverse channel assignment process. Reverse channel assignment can also be used for other bins as an option.

A transmission device includes a symbol generator that generates a modulation symbol by mapping transmission data to a signal point arranged in a two-dimensional or three-dimensional color space; and an outputter that outputs an optical signal modulated according to the modulation symbol.

A system and method for performing an in-service optical time domain reflectometry test, an in-service insertion loss test, and an in-service optical frequency domain reflectometry test using a same wavelength as the network communications for point-to-point or point-to-multipoint optical fiber networks while maintaining continuity of network communications are disclosed.

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.

An optical network including a plurality of gateway nodes interconnected with a plurality of intermediate nodes with segments of fiber. The network includes a plurality of devices, such as reconfigurable optical add drop multiplexers, optimally placed at various nodes throughout the network. The device placement is optimized with an integer linear programming analysis considering span definition such that any given span involves some number of segments not exceeding a number of segments that would require wavelength regeneration, cost of placement of a device at a given node, cost of wavelength regeneration, and various parameters and constraints.

An optical transmission apparatus (1_1) according to the present invention includes a first transmission unit (11_1) that transmits a first optical transmission signal (21_1), a second transmission unit (11_2) that transmits a second optical transmission signal (21_2), and an output unit that outputs, when the first optical transmission signal (21_1) and the second optical transmission signal (21_2) share a set of information, both the first optical transmission signal (21_1) and the second optical transmission signal (21_2) to a first path (26_1) and outputs, when the first optical transmission signal (21_1) and the second optical transmission signal (21_2) do not share the set of information, one of the first optical transmission signal (21_1) and the second optical transmission signal (21_2) to a second path (26_2).

A method and system are provided for continuously monitoring bandwidth utilization in real time on a backbone of a network. Prefixes using the highest traffic can be identified and additional bandwidth can be provisioned in the form of optical transponder wavelengths. The additional bandwidth can be an express path that passes directly through optical nodes (thereby bypassing transit network devices) to the destination optical node. A centralized controller can perform the monitoring of the network devices, decide that an express path needs to be generated, and control both the network device and the optical network nodes to generate the express path from the network device, through the optical network, to the destination network device. The controller can apply and remove IP static routes and IP addresses associated with an express path. Additionally, the controller can request the setup or tear-down of an optical wavelength within the optical network.

A wavelength multiplexing communication system includes a master station apparatus and a plurality of slave station apparatuses. The master station apparatus includes a wavelength multiplexing communication unit that performs wavelength multiplexing communication with the plurality of slave station apparatuses by wavelengths the number of which is equal to or less than the number of the plurality of slave station apparatuses using an optical signal of a wavelength in a first wavelength group and an optical signal of a wavelength in a second wavelength group. The slave station apparatuses include an optical communication unit that performs communication of the main signal with the master station apparatus by an optical signal of a wavelength in the first wavelength group, which is different from a wavelength in the first wavelength group used by another slave station when the main signal communication is performed in the host slave station apparatus, and performs communication of a signal other than the main signal with the master station apparatus by an optical signal of a wavelength in the second wavelength group, which is a wavelength same as a wavelength used by another slave station apparatus when the main signal communication is not performed in the host slave station apparatus.