A protection switching method, including sending, by a first end node, a first protection switching request message to an intermediate node in response to a fault occurring on a working trail between the first end node and a second end node, wherein a protection trail of the working trail comprises the first end node, the second end node, and at least one intermediate node, receiving, by the first end node, a second protection switching request message from the intermediate node, and switching service data to the protection trail for transmission in response to receiving the second protection switching request message, where one overhead frame of each of the first and second protection switching request messages has at least two overhead information groups, and each of the at least two overhead information groups comprises a request type field, a request signal identifier field, and a bridge flag field.

Embodiments providing improved systems and methods deploying, monitoring, and troubleshooting optical physical layer networks are needed. In one embodiment, networks are first constructed in a specialized network factory, where they are racked, provisioned, audited, and tested by relevant experts in each technology. Then the equipment is custom-cratedwith all cards, patch cords, labels, and provisioning in placebefore being shipped to field locations. A production network health baseline is captured that creates a set of norms that later performance data can be compared against. Once the network is operational, the network health is monitored and compared against the baseline. If there's a deviation sufficient to satisfy a user-defined rule, a remedial action can be triggered. In another embodiment, a method isolates a problem in an optical transport network.

Embodiments providing improved systems and methods deploying, monitoring, and troubleshooting optical physical layer networks are needed. A baseline may be created and performance data is extracted. The performance data is compared against user-defined rules to determine an appropriate action. In one embodiment, networks are first constructed in a specialized network factory, where they are racked, provisioned, audited, and tested by relevant experts in each technology. In another embodiment, a method isolates a problem in an optical transport network. When a problem is identified, the layers are repeatedly evaluated to identify the device operating at the lowest layer where an error occurs. That device is identified as being likely faulty.

A fault detection method and device is disclosed. The method includes obtaining, by an optical transport network (OTN) device, a first OTN frame. The first OTN frame includes a plurality of payload areas. Each payload area includes payload check information and payload data. The method further includes performing fault detection, according to the payload check information, of payload data of a payload area in which the payload check information is located. The first OTN frame is divided into a plurality of payload areas, and corresponding payload check information is carried in each payload area.

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 obtaining and storing a first power spectral density snapshot of an optical link, from an optical spectrum monitor and when the optical link is in a non-fault condition; responsive to detection of a fault on channels traversing the optical link, obtaining a second power spectral density snapshot at a receiving end of the optical link; analyzing the first power spectral density snapshot and the second power spectral density snapshot; and determining the fault is on the optical link based on the analyzing.

A system and method is disclosed in which circuitry of a first controller of a first node on a first path within a transport network receives a first signal indicating a failure within the first path from a second controller. The first node is an end node of the first path. A first client signal failure clear signal is received from a second node upstream of the first node on the first path. The first client signal failure clear signal indicates that a non-restorable fault has been resolved such that the first path can be considered for carrying data traffic. The non-restorable fault is a failure at the source. Subsequent to receiving the first signal indicating the failure within the first path, a backward defect indication clear signal is transmitted to the second node, the backward defect indication clear signal indicating an absence of a failure in the first path.

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.

A service modification method includes, in a node which is part of a network controlled by a control plane, routing a connection off of its home path to a current path which is at least partially disjoint from the home path and creating a reservation for the connection on the home path such that the connection can revert thereto; signaling a modification of the connection while it is on the current path; and updating the reservation based on the modification including signaling the modification to all nodes on the home path. The service modification method can further include reverting the connection to the home path with the modification. The updating can fail due to an inability to support the modification on the home path, and the service modification method can further include periodically retrying the updating the reservation based on the modification.

A service modification method includes, in a node which is part of a network controlled by a control plane, routing a connection off of its home path to a current path which is at least partially disjoint from the home path and creating a reservation for the connection on the home path such that the connection can revert thereto; signaling a modification of the connection while it is on the current path; and updating the reservation based on the modification including signaling the modification to all nodes on the home path. The service modification method can further include reverting the connection to the home path with the modification. The updating can fail due to an inability to support the modification on the home path, and the service modification method can further include periodically retrying the updating the reservation based on the modification.

A service protection method includes a first node that determines that a fault has occurred on a first working path, and generates a service switching message based on the fault on the first working path. The first node sends the service switching message on a first protection path, where the service switching message indicates to adjust a bandwidth of a service from a guard bandwidth to a target bandwidth, where the guard bandwidth represents a pre-occupied bandwidth of the first protection path before the service is transmitted, where the target bandwidth represents an occupied bandwidth for transmitting the service on the first protection path, and where the guard bandwidth is less than the target bandwidth.