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.

A method including receiving, by a device in communication with a first endpoint and a second endpoint in a mesh network, a first communication from the first endpoint and a second communication from the second endpoint; selectively comparing, by the device, first observed connection state information associated with the first communication with the stored connection state information associated with outgoing communications transmitted by the device, and second observed connection state information associated with the second communication with the stored connection state information; and selectively processing, by the device, the first communication based at least in part on a result of selectively comparing the first observed connection state information with the stored connection state information, and the second communication based at least in part on a result of selectively comparing the second observed connection state information with the stored connection state information. Various other aspects are contemplated.

Disclosed herein are switch devices in terminal ends of a network and methods of using same. One embodiment relates to a terminal end of a network including a terminal end transceiver configured to communicate with one or more end user devices, and a switch device configured to automatically route communication at the terminal end transceiver between a primary communication path with a central office and an auxiliary communication path with the central office. Another embodiment relates to a method of switching between primary and auxiliary communication paths at a terminal end. Automatic switching is particularly applicable in a looped communication architecture with redundant communication paths for preventing interruption and increasing reliability for an improved user experience. Another embodiment relates to indexing with splices to reduce connections in a communication path and increase signal quality.

A method includes, for each optical fiber path in an optical network, allocating an optical wavelength channel in an optical spectrum such that the allocated optical wavelength channel is assigned to support optical communications over the optical fiber path. The method also includes updating an allocation table in response to performing the allocating for one or more of the optical fiber paths; the allocating including determining the optical wavelength channel to be allocated based on a state of the allocation table. The allocation table indicates optical wavelength channels allocated over optical fiber spans of the optical network. The method also includes defining a set of optical sub-bands to cover a part of the optical spectrum in response to a state of the allocation table satisfying a fullness property. The optical sub-bands are such that each of the allocated wavelength channels is in one of the optical sub-bands.

A method including receiving, by a first device in communication with a second device in a mesh network, an incoming packet from the second device; determining, by the first device, that the incoming packet is an initiation packet requesting information or a response from the first device or a response packet providing a response to an outgoing packet transmitted by the first device; and processing, by the first device, the incoming packet based at least in part on determining that the incoming packet is the initiation packet or the response packet. Various other aspects are contemplated.

A passive signal transport medium, constructed as an array of spectral-temporal connectors, connects a large number of access nodes to a number of distributors to form a single-hop network of wide coverage and high throughput yet simplified control. Parameterized spectral-temporal connectors define network expansion over networks using conventional signal transport media. A network accommodating 32000 access nodes with a throughput of an Exabits/second is realizable. The distributors may be geographically distributed (the access nodes are naturally geographically distributed). The entire network structure is parameterized. Selecting the number of distributors to equal the number of access nodes, and pairing each access node with a respective distributor to form an integrated node, an expanded fully-meshed network is realized with each pair of integrated nodes having a direct path and numerous single-hop paths. Several routing schemes within the fully-meshed network are considered to enable both global control and distributed control.

A method includes: determining, by the control device, that a site receives a first service; determining that a mapping wavelength of a first service is blocked on an original routing path, where the original routing path includes a first line board connected to a first local dimension, and a wavelength occupied by the first local dimension includes the mapping wavelength of the first service; and routing, by the control device, the first service to a second line board connected to a second local dimension, where the mapping wavelength of the first service is available in the second local dimension.

A control apparatus includes an optical wavelength change control unit that specifies, in response to a request to change a wavelength band of a first optical wavelength path used by a first transmission apparatus and a second transmission apparatus to a wavelength band of a second optical wavelength path, a first route between routers which is affected by the request and a service which uses the first route and that specifies a second route between the routers which detours the specified service; a router control unit that transmits a request to detour the specified service to the second route, to a start-point router and an end-point router on the first route; and a transmission apparatus control unit that transmits a request to change the wavelength band of the first optical wavelength path to the wavelength band of the second optical wavelength path, to the first transmission apparatus and the second transmission apparatus.

In an optical communication network that includes a plurality of interconnected network nodes, a method includes storing in each network node, and for each communication channel that traverses the node, one or more impairment margins of respective impairments that affect the communication channel. A potential communication channel that traverses a subset of the nodes in the network is identified. A quality of the potential communication channel is evaluated by processing the impairment margins stored in the nodes in the subset.

A network capable of being used in a datacenter is described. In some embodiments, the network can comprise a set of optical fiber rings, wherein each optical fiber ring carries data traffic on one or more wavelengths, and wherein each optical fiber ring is partitioned into multiple sectors. A reconfigurable optical add-drop multiplexer (ROADM) can be coupled to at least one optical fiber in each of at least two sectors. An electro-optical-switch can be coupled to each ROADM in each of the at least two sectors. A set of switches can be coupled to each electro-optical-switch in each of the at least two sectors. The set of switches can comprise a first layer of aggregation switches that is coupled to a second layer of edge switches, wherein the edge switches can be coupled to servers in a datacenter.