Method for Controlling Response to Communication Faults in a ROADM-Based Backbone Optical Transport System and Apparatus Therefor

Abstract

A method for controlling communication failure response in a ROADM-based backbone network optical transmission system and an apparatus for the same are disclosed. A method for controlling communication failure response according to an embodiment of the present invention may include: a monitoring result acquisition step of acquiring a monitoring result including a communication failure determination result and basis information from a communication status monitoring module; a communication failure severity confirmation step of confirming the severity of the communication failure based on a preset operational context; a response action selection step of selecting a response scenario based on the severity and current network status information; a communication failure response control step of applying a control command to an optical transmission processing device according to the selected response scenario; and a verification and backup response step of re-measuring a monitoring indicator after applying the control command to verify the result, and performing an alternative procedure in the event of a verification failure.

Description

Technology Field

[0001] The present invention relates to a method for controlling communication failure response in a ROADM-based backbone network optical transmission system and an apparatus for the same. Background Technology

[0002] The content described in this section merely provides background information regarding embodiments of the present invention and does not constitute prior art.

[0003] Backbone optical transmission networks serve as core infrastructure constituting the backbones of national or wide-area operators. They consist of Reconfigurable Optical Add-Drop Multiplexing (ROADM)-based wavelength division multiplexers, transmission amplifiers, wavelength selection switches, optical terminals, and OTN cross-connects. These transmission networks interconnect nodes in multiple regions via light paths and require high availability and reliability as they accommodate delay-sensitive services such as traffic control and public safety.

[0004] In conventional technology, communication status monitoring is primarily performed at the individual equipment or individual link level. For instance, alarms are triggered by setting thresholds for indicators such as optical signal power, optical signal-to-noise ratio, bit error rate, signal loss, frame loss, latency, and amplifier gain, and operators determine the presence of a failure by analyzing the alarm list. Recovery is performed through fixed protection methods such as 1+1, 1:1, and 1:N protection switching, or through rerouting functions based on GMPLS (Generalized Multiprotocol Label Switching), ASON (Automatically Switched Optical Network), and SDN (Software-Defined Networking). However, these conventional methods have the following structural limitations.

[0005] Fault determination tends to be skewed toward whether a single metric threshold is exceeded, making it sensitive to environmental changes or transient peaks, and lacks systematic interpretation such as normalization and leveling that consider combinations of multiple conditions. Since operational contexts such as node importance, service level, time zone, and equipment status are not reflected, a problem arises where severity assessments diverge from actual impact.

[0006] Furthermore, correlation analysis across the entire topology is limited. It is difficult to rapidly identify cascading anomalies among adjacent nodes or domain-level segment failures; consequently, the estimation of the radius of impact and the selection of bypass paths are delayed, leading to an increase in the Mean Time to Recover (MTTR). The problem to be solved

[0007] The main objective of the present invention is to provide a method for controlling communication failure response in a backbone network optical transmission system and an apparatus therefor, which checks the severity of a communication failure through communication status monitoring, selects a response scenario based on the severity and current network status information, and applies control commands to an optical transmission processing device according to the selected response scenario. means of solving the problem

[0008] According to one aspect of the present invention, a method for controlling a communication failure response of a backbone network optical transmission system to achieve the above objective comprises: a monitoring result acquisition step of acquiring a monitoring result including a communication failure judgment result and basis information from a communication status monitoring module; a communication failure severity confirmation step of confirming the severity of the communication failure based on a preset operational context; a response action selection step of selecting a response scenario based on the severity and current network status information; a communication failure response control step of applying a control command to an optical transmission processing device according to the selected response scenario; and a verification and backup response step of remeasuring a monitoring indicator after applying the control command to verify the result, and performing an alternative procedure in the event of a verification failure.

[0009] In addition, according to another aspect of the present invention, a communication failure response control device for a backbone network optical transmission system for achieving the above objective, the communication failure response control device may include: a monitoring result acquisition unit configured to acquire a monitoring result including a communication failure judgment result and basis information from a communication status monitoring module; a communication failure severity verification unit configured to verify the severity of the communication failure based on a preset operational context; a response action selection unit configured to select a response scenario based on the severity and current network status information; a communication failure response control unit configured to apply a control command to an optical transmission processing device according to the selected response scenario; and a verification and backup response processing unit configured to verify the result by re-measuring a monitoring indicator after the application of the control command, and to perform an alternative procedure if the verification fails. Effects of the invention

[0010] As explained above, the present invention has the effect of reducing the recovery time for communication failures and minimizing service damage by controlling the response to communication failures through the selection of a response scenario via operational context-based severity correction. Brief explanation of the drawing

[0011] FIG. 1 is a block diagram schematically showing a backbone network optical transmission system according to an embodiment of the present invention. FIG. 2 is a block diagram schematically showing a communication failure response device according to an embodiment of the present invention. FIG. 3 is a flowchart for explaining a backbone network optical transmission method according to an embodiment of the present invention. FIG. 4 is a flowchart for explaining a communication failure response control method according to an embodiment of the present invention. FIG. 5 is a diagram showing a node connection network based on a backbone network optical transmission system according to an embodiment of the present invention. Specific details for implementing the invention

[0012] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, detailed descriptions of related known configurations or functions are omitted if it is determined that such detailed descriptions may obscure the essence of the present invention. Furthermore, while preferred embodiments of the present invention will be described below, the technical concept of the present invention is not limited or restricted thereto and can be modified and implemented in various ways by those skilled in the art. Hereinafter, with reference to the drawings, a method for controlling communication failure response in a ROADM-based backbone network optical transmission system and an apparatus for such response proposed in the present invention will be described in detail.

[0013] FIG. 1 is a block diagram schematically showing a backbone network optical transmission system according to an embodiment of the present invention.

[0014] The backbone network optical transmission system (10) according to the present embodiment includes an optical transmission processing device (20), a traffic data processing device (30), and a communication inspection device (40). Here, the communication inspection device (40) may be equipped with a communication status monitoring module (42) for monitoring the communication status and a communication failure response module (44) for executing a response operation when a failure occurs.

[0015] The backbone network optical transmission system (10) of FIG. 1 is according to one embodiment, and not all blocks shown in FIG. 1 are essential components, and some blocks included in the backbone network optical transmission system (10) in other embodiments may be added, changed, or deleted.

[0016] The backbone network optical transmission system (10) refers to a system deployed at each of the multiple nodes of a backbone network based on ROADM (Reconfigurable Optical Add-Drop Multiplexing). The backbone network optical transmission system (10) deployed at each node can be configured with equipment capable of long-distance, high-capacity communication using wavelength division multiplexing and allowing communication between equipment to be freely reconfigured through software settings.

[0017] The backbone network optical transmission system (10) deployed at each node is configured with the same or similar structure and exchanges optical signals and management information through optical links between nodes.

[0018] Each component included in the backbone network optical transmission system (10) may be implemented by dedicated hardware, firmware, software, or a combination thereof. The names of specific components are merely examples to describe their functions, and replacing them with other components that perform the same function does not deviate from the essence of the invention.

[0019] The optical transmission processing device (20) is configured to receive, convert, and transmit optical signals at the transmission layer. The optical transmission processing device (20) includes a data receiving module (22) and a data transmitting module (24).

[0020] The optical transmission processing device (20) can perform optical layer operations such as light path setting, wavelength resource placement, and power correction.

[0021] The data receiving module (22) receives an optical signal input through the backbone network, calculates observations such as optical signal power, optical signal-to-noise ratio, bit error rate, signal loss, frame loss, amplifier gain, wavelength drift, delay time, and protection line switching event, and provides them to the communication status monitoring module (42) of the communication inspection device (40).

[0022] The data transmission module (24) maps traffic data provided by the traffic data processing device (30) to a set wavelength and transmits it as an optical signal, and provides a set value and status information generated by transmission path setting or power correction to the communication status monitoring module (42). The optical transmission processing device (20) may be configured to exchange status information and alarms with the communication inspection device (40) through an interface using a network configuration protocol and a data model. Here, the interface may be NETCONF and YANG, gNMI or TL1, etc.

[0023] The data transmission module (24) performs operations such as path resetting, amplifier parameter adjustment, variable optical attenuator setting adjustment, and light path reconstruction according to control commands received from the communication failure response module (44).

[0024] The traffic data processing device (30) normalizes, filters, and aggregates data collected from traffic-related applications and provides traffic data quality indicators to the communication inspection device (40) when necessary. The traffic data processing device (30) is connected to the communication inspection device (40) via a management interface and can be linked to changes in information transmission policies or notification procedures directed by the communication failure response module (44). However, in this embodiment, the primary control target of the communication failure response control is the optical transmission processing device (20).

[0025] The traffic data processing device (30) is configured to collect traffic data from a traffic sensor or control system, perform normalization, filtering, and aggregation, provide it to an application system, or link with the optical transmission processing device (20).

[0026] The traffic data processing device (30) calculates observations such as message delay time, loss rate, throughput, queue length, and response time and provides them to the communication status monitoring module (42). Here, the observations are set as monitoring conditions by the communication status monitoring module (42) and are used for fault determination along with transmission layer indicators.

[0027] The communication inspection device (40) is a device that collects, analyzes, and controls the status of the backbone network optical transmission system (10).

[0028] The communication inspection device (40) includes a communication status monitoring module (42) and a communication failure response module (44).

[0029] The communication status monitoring module (42) collects observations from the optical transmission processing device (20) and the traffic data processing device (30), performs monitoring condition setting, preprocessing, normalization, and level calculation, and then determines whether a communication failure has occurred based on a combination of condition-specific levels. The communication status monitoring module (42) generates a monitoring result including basis information such as threshold values, weights, observation windows, and topology reference information used along with the determination result, and provides it to the communication failure response module (44).

[0030] Specifically, the communication status monitoring module (42) sets monitoring conditions. The monitoring conditions may include at least one of optical signal power, optical signal-to-noise ratio, bit error rate, signal loss, frame loss, amplifier gain, wavelength drift, delay time, and protection line switching event, and additionally may include at least one of traffic data indicators such as message delay time, loss rate, throughput, queue length, and response time.

[0031] The communication status monitoring module (42) can set up topology information including connection relationships between nodes and path information, as well as policy information such as measurement cycles, observation windows, thresholds, and weights.

[0032] The communication status monitoring module (42) acquires observation values. The acquisition of observation values ​​is performed according to a set measurement cycle and observation window, and preprocessing is performed using a moving average method, an exponential smoothing method, or a window-based statistical processing method to reduce the influence of temporary peak values. Since the preprocessed observation values ​​have different units and ranges, the communication status monitoring module (42) normalizes the preprocessed observation values ​​and converts them into a common scale.

[0033] The communication status monitoring module (42) calculates a level. A pre-set interval mapping or function mapping is applied to the normalized observation value to calculate the level for each monitoring condition. When calculating the level, the level rise threshold applied to the level rise and the level fall threshold applied to the level fall are set differently, and a hold-off time is applied to suppress flapping.

[0034] The communication status monitoring module (42) determines whether a communication failure has occurred. In the determination process, a condition weight is applied to the level of each monitoring condition, and a node importance weight is additionally applied to the cumulative value to which the condition weight is applied to calculate a weighted level. The node importance weight is calculated based on the number of connected nodes, the amount of data processed by the nodes, and the equipment scale of the nodes, and can be dynamically adjusted according to the time zone, service level, and equipment status.

[0035] Additionally, the communication status monitoring module (42) analyzes the correlation of observations of adjacent nodes based on topology information and increases the reliability of the judgment by increasing the weight when an anomaly is detected in consecutive nodes. The combination method of conditional levels can be implemented as at least one of a rule-based combination method, a statistics-based combination method, or a machine learning-based combination method.

[0036] The communication status monitoring module (42) records and notifies the judgment result. The judgment result can be classified into one of the warning stage, the alert stage, or the critical stage, and the threshold, weight, observation window, and topology reference information used along with the judgment result are stored as an event record. Here, the judgment result and the event record can be transmitted to a peripheral backbone network optical transmission system or an external management system, and the stored event record can be used for adaptive updates that periodically reset the threshold.

[0037] The communication failure response module (44) obtains monitoring results from the communication status monitoring module (42) and performs communication failure response control based on the obtained monitoring results.

[0038] The communication failure response module (44) can perform communication failure response control in at least one of the following methods based on the monitoring results: light path resetting, protection line switching, amplifier setting value readjustment, variable optical attenuator setting value readjustment, optical transmission network reconnection, traffic data transmission speed adjustment, and buffering control.

[0039] The communication failure response module (44) checks the severity of the communication failure based on the operational context and selects a response scenario based on current network status information. According to the selected response scenario, the communication failure response module (44) applies a control command to the optical transmission processing unit (20) and verifies the result by remeasuring the monitoring indicator after applying the control command. If the verification result does not satisfy the criteria, the communication failure response module (44) performs alternative procedures such as rollback, retry, and alternative path switching.

[0040] The internal configuration of the communication failure response module (44) may include a monitoring result acquisition unit, a communication failure severity check unit, a response action selection unit, a communication failure response control unit, and a verification and backup response processing unit, and a detailed description of each configuration is provided in FIG. 2.

[0041] FIG. 2 is a block diagram schematically showing a communication failure response device according to an embodiment of the present invention.

[0042] The communication failure response device (600) according to the present embodiment refers to a device corresponding to the communication failure response module (44). The communication failure response device (600) includes a monitoring result acquisition unit (602), a communication failure severity verification unit (610), a response action selection unit (620), a communication failure response control unit (630), and a backup response processing unit (640). The communication failure response device (600) of FIG. 2 is according to one embodiment, and not all blocks shown in FIG. 2 are essential components, and some blocks included in the communication failure response device (600) in other embodiments may be added, changed, or deleted.

[0043] The communication failure response device (600) performs a communication failure response operation in conjunction with the optical transmission processing device (20) and the traffic data processing device (30). Each component of the communication failure response device (600) may operate independently and may be implemented in software, firmware, or hardware. Specific functions may be integrated into a single component or distributed among multiple components, and even if they are replaced by other means performing the same function, it does not deviate from the essence of the invention.

[0044] Below, each component included in the communication failure response device (600) will be described.

[0045] The monitoring result acquisition unit (602) receives monitoring results from the communication status monitoring module (42). The monitoring results include a communication failure judgment result (e.g., a stage of normal, caution, alert, severe, or a failure flag) and information on the basis for the judgment. Here, the information on the basis for the judgment may include a level for each monitoring condition, a threshold value used, a condition weight and a node importance weight, an observation window, a measurement period, topology reference information (node ​​or link identifier, path identifier, adjacency relationship information), and the time (time stamp) used for the judgment.

[0046] The monitoring result acquisition unit (602) performs deduplication based on event identifiers and timestamps to eliminate duplicates of the same event, and correlates the results received simultaneously from multiple nodes. Additionally, the monitoring result acquisition unit (602) can query operational context (e.g., time zone, service level, protection path availability, remaining resource capacity, equipment status, etc.) from a policy repository (not shown), and acquire current network status information (e.g., topology information, protection path status, remaining link or node capacity, ongoing change operations, history of pre-failure actions, etc.) from a network inventory and telemetry system and transmit it to the communication failure severity verification unit (610).

[0047] The communication failure severity verification unit (610) calculates the severity using the communication failure judgment result, basis information, and operational context transmitted from the monitoring result acquisition unit (602). The base severity (Level_base) is mapped to the level value of the monitoring result, and the operational context vector C = {c 시간대 ,c 서비스등급 ,c 보호경로 ,c 잔여용량 ,c 장비상태 The corrected severity is calculated by applying a weight (W) corresponding to}. The corrected severity (Level) can be defined as [Equation 1].

[0048]

[0049] The communication failure severity verification unit (610) analyzes topology reference information to classify the event into single node failure, segment failure, domain failure, etc., and determines control range candidates (e.g., set of target devices, path segment) based on the classification result.

[0050] Additionally, the communication failure severity verification unit (610) calculates a time limit value for action by referring to the service-specific recovery time objective (RTO) and availability objective, and provides the calculated limit value to the response action selection unit (620).

[0051] The response action selection unit (620) selects one or more response scenarios based on correction severity, action time limit value, and current network status information. Examples of response scenarios include protection path switching, light path resetting, ROADM wavelength repositioning, transmission amplifier gain readjustment, variable optical attenuator setting adjustment, preamplifier boost order change, temporary transmission power adjustment, service priority resetting, and speed limiting of a specific path.

[0052] The corresponding action selection unit (620) calculates a multi-target score function and selects a scenario in which the score J is minimized. The corresponding action selection unit (620) can calculate a multi-target score function as in [Equation 2].

[0053]

[0054] Here, T 복구 is the predicted recovery time, B 영향반경 is the number of affected services or traffic volume, N 변경건수 is the number of configuration changes, R 리스크 is an indicator of the probability of failure, and α, β, γ, and δ are set according to policy.

[0055] It is set according to the policy.

[0056] The corresponding action selection unit (620) performs a preliminary simulation based on equipment models (e.g., YANG schema and vendor command template) and current network status information to estimate the success probability for each scenario, and maintains only the scenario candidates whose estimated success probability satisfies a threshold value or higher.

[0057] Additionally, the corresponding action selection unit (620) performs path search in the topology graph to calculate the radius of influence of the corresponding scenario, and if it exceeds a preset influence limit, it automatically replaces it with an alternative scenario.

[0058] The response action selection unit (620) generates a preliminary application plan for a representative node or representative section when necessary and defines success criteria and monitoring indicators. Here, the preliminary application plan refers to an execution plan to apply changes to the scenario to a representative node or representative section on a limited basis before applying them to the entire network, and to determine whether to expand or roll back to the entire network after verifying safety according to predefined success criteria and monitoring indicators.

[0059] The communication failure response control unit (630) applies the selected response scenario in a plurality of step procedures. Here, the procedures may consist of a pre-verification, partial application, full application, post-verification, and rollback in case of failure steps, and a step to check whether the equipment status and monitoring indicators meet the criteria may be added between each step.

[0060] The communication failure response control unit (630) transmits control commands via a management protocol (e.g., NETCONF and YANG, gNMI or TL1, etc.) and can perform a two-phase commit procedure using a confirmation commit for consistent application to multiple devices. The communication failure response control unit (630) automatically reverts to the previous configuration if no response is received within the commit confirmation timer or if the verification conditions are not satisfied.

[0061] The communication failure response control unit (630) constructs a dependency relationship graph between the amplifier, wavelength selection switch, optical terminal, and packet equipment to safely handle dependencies between various equipment and layers, and executes commands in a safe order according to the graph topology. For example, the communication failure response control unit (630) may apply a sequence in which it pre-adjusts the amplifier output, performs wavelength switching of the ROADM, and finally performs activation of the terminal port.

[0062] The communication failure response control unit (630) saves a snapshot of the prior change and also performs protection procedures such as limiting the change rate, verifying the maintenance window, and checking access rights.

[0063] The backup response processing unit (640) receives the re-measurement result of the monitoring indicator after the application of the control command and determines whether the target range is satisfied, and if the target is not satisfied, automatically escalates to a response scenario of higher intensity according to closed-loop verification. Here, escalation means the operation of changing to and applying a response scenario of higher intensity.

[0064] If the backup response processing unit (640) fails even with escalation, it sequentially performs full rollback, partial rollback, retrying the configuration, and alternate path switching according to the priority.

[0065] Additionally, the backup response processing unit (640) can stabilize the network in a progressively degraded (grayful degrade) state by applying a transmission speed limit and a lowering of queue priority for low-importance services according to the service grade policy.

[0066] The backup response processing unit (640) stores the results of all actions, parameters used and grounds, and success or failure history as an event record, and analyzes the record to recommend to the response action selection unit (620) that past success scenarios of similar patterns be selected first. Here, the event record can be used to adaptively update policies such as thresholds, weights, and impact limits over the long term.

[0067] FIG. 3 is a flowchart for explaining a backbone network optical transmission method according to an embodiment of the present invention.

[0068] The backbone network optical transmission system (10) performs optical communication-based data transmission and reception (S310).

[0069] In step S310, the optical transmission processing device (20) receives, converts, and transmits optical signals input and output through the backbone network.

[0070] The optical transmission processing device (20) calculates observation values ​​regarding optical signal power, optical signal-to-noise ratio, bit error rate, signal loss, frame loss, amplifier gain, wavelength drift, delay time, and protection line switching event through the data receiving module (22) and provides them to the communication status monitoring module (42) of the communication inspection device (40). The optical transmission processing device (20) transmits traffic data provided from the traffic data processing device (30) by mapping it to a set wavelength through the data transmission module (24), and transmits the set value and status information generated by transmission path setting or power correction to the communication status monitoring module (42).

[0071] The backbone network optical transmission system (10) performs traffic data processing (S320).

[0072] In step S320, the traffic data processing device (30) collects traffic data from a traffic sensor or control system, performs normalization, filtering, and aggregation, and provides it to an application system or links with the optical transmission processing device (20). The traffic data processing device (30) calculates observations regarding message delay time, loss rate, throughput, queue length, and response time, and provides them to the communication status monitoring module (42).

[0073] The backbone network optical transmission system (10) performs communication status monitoring (S330).

[0074] In step S330, the communication status monitoring module (42) of the communication inspection device (40) sequentially performs the processing of setting monitoring conditions, acquiring observation values, preprocessing, normalization, level calculation, determining communication failures, and notifying the recording of judgment results. The communication status monitoring module (42) sets at least one of optical signal power, optical signal-to-noise ratio, bit error rate, signal loss, frame loss, amplifier gain, wavelength drift, delay time, and protection line switching event, and at least one of message delay time, loss rate, throughput, queue length, and response time as monitoring conditions through the monitoring condition setting unit (210), and stores policies regarding topology information, measurement cycle, observation window, threshold, condition weight, node importance weight, and holdoff time. The communication status monitoring module (42) acquires observation values ​​from the optical transmission processing device (20) and the traffic data processing device (30) through the observation value acquisition unit (220), and performs preprocessing using a moving average method, an exponential smoothing method, or a window-based statistical processing method to reduce the influence of transient peak values. The communication status monitoring module (42) normalizes the observations preprocessed through the level calculation unit (230) for different units and ranges and converts them into a common scale, and calculates a level for each monitoring condition by applying a pre-set interval mapping or a pre-set function mapping. The level calculation unit (230) suppresses flapping by setting the level rise threshold and the level fall threshold differently and applying a hold-off time. The communication status monitoring module (42) determines whether a communication failure has occurred by combining the levels for each condition through the communication failure determination unit (240). The communication failure determination unit (240) calculates a cumulative value by applying a condition weight to the level of each monitoring condition, calculates a weighted level by applying a node importance weight to the cumulative value, and then compares it with a predetermined threshold.The communication failure judgment unit (240) analyzes the correlation of observation values ​​of adjacent nodes based on topology information and, when an anomaly is detected in consecutive nodes, increases the reliability of the judgment by increasing the condition weight or node importance weight. The communication status monitoring module (42) classifies the judgment result into one of the warning, alert, or severe stages through the judgment result recording notification unit (250), stores the threshold value, weight, observation window, and topology reference information used together with the judgment result as an event record, and transmits the event record and the judgment result to a peripheral backbone network optical transmission system or an external management system.

[0075] The backbone network optical transmission system (10) can perform communication failure response processing (S340).

[0076] In step S340, the communication failure response module (44) of the communication inspection device (40) receives the judgment result and stage classification calculated by the communication failure judgment unit (240) in step S330 as input, and selects and executes at least one response operation among lightpath path resetting, protection line switching, amplifier setting value readjustment, variable optical attenuator setting value readjustment, optical transmission network reconnection, traffic data transmission speed adjustment, and buffering control. The communication failure response module (44) transmits control commands to the optical transmission processing device (20) or the traffic data processing device (30) via the NETCONF and YANG, gNMI, or TL1 interfaces. The detailed operation and policy mapping of the communication failure response module (44) may be described in detail in a separate embodiment regarding the communication failure response control method and the device for the same.

[0077] If the result of step S330 is determined not to be a communication failure, the backbone network optical transmission system (10) returns to step S330 according to the set measurement cycle and continues monitoring. If the result of step S330 is determined to be a communication failure, step S340 may be executed. The backbone network optical transmission system (10) updates the monitoring conditions, thresholds, weights, and observation windows according to policy changes from an external management system, and distributes the updated policy to the monitoring condition setting unit (210) so that it can be applied to subsequent cycles.

[0078] Although FIG. 3 describes each step as being executed sequentially, it is not necessarily limited to this. In other words, FIG. 3 is not limited to a chronological order, as it may be applicable to execute the steps described in FIG. 3 by modifying them or to execute one or more steps in parallel.

[0079] The backbone network optical transmission method according to the present embodiment described in FIG. 3 can be implemented as an application (or program) and recorded on a recording medium readable by a terminal device (or computer). The recording medium on which the application (or program) for implementing the backbone network optical transmission method according to the present embodiment is recorded and which is readable by a terminal device (or computer) includes all types of recording devices or media in which data that can be read by a computing system is stored.

[0080] FIG. 4 is a flowchart for explaining a communication failure response control method according to an embodiment of the present invention.

[0081] The communication failure response device (600) receives a monitoring result including a communication failure judgment result and information on the basis of the judgment from the communication status monitoring module (42) through the monitoring result acquisition unit (602) (S410). Here, the information on the basis of the judgment may include a level for each monitoring condition, a threshold value used, a condition weight and a node importance weight, an observation window, a measurement period, topology reference information (node ​​or link identifier, path identifier, adjacency relationship information), and a time used for the judgment.

[0082] The communication failure response device (600) calculates the severity using the communication failure judgment result, basis information, and operational context through the communication failure severity verification unit (610) (S420). The operational context may include at least one of time zone, service level, protection path availability, remaining resource capacity, equipment status, etc., and the communication failure severity verification unit (610) calculates the severity by correcting the step value of the monitoring result according to the operational context.

[0083] The communication failure response device (600) selects a response scenario based on severity and current network status information through the response action selection unit (620) (S430). The current network status information may include at least one of topology information, protection path status, remaining capacity of links and nodes, status of ongoing change operations, and history of pre-failure measures. Examples of response scenarios include protection path switching, light path resetting, transmission amplifier gain adjustment, variable optical attenuator setting adjustment, and wavelength resource reallocation.

[0084] The communication failure response device (600) applies a control command to the optical transmission processing device (20) according to a response scenario selected through the communication failure response control unit (630) (S440). The control command is transmitted through a management interface and may include, for example, reconfiguration of the light path, adjustment of amplifier parameters, wavelength switching, or change of transmission / reception port settings.

[0085] The communication failure response device (600) verifies the result by re-measuring the monitoring indicator after applying the control command through the verification and backup response processing unit (640) (S450).

[0086] If the re-measured monitoring indicator does not satisfy the target range, the verification and backup response processing unit (640) performs an alternative procedure such as rollback, retry, alternate path failover, or gradual degradation of a low-priority service (S460). When the network state is stabilized through the execution of the verification and alternative procedure, the procedure is terminated.

[0087] Although FIG. 4 describes each step as being executed sequentially, it is not necessarily limited to this. In other words, since it is possible to modify and execute the steps described in FIG. 4 or to execute one or more steps in parallel, FIG. 4 is not limited to a chronological order.

[0088] The communication failure response control method according to the present embodiment described in FIG. 4 may be implemented as an application (or program) and recorded on a recording medium readable by a terminal device (or computer). The recording medium, on which the application (or program) for implementing the communication failure response control method according to the present embodiment is recorded and which is readable by a terminal device (or computer), includes all types of recording devices or media in which data that can be read by a computing system is stored.

[0089] FIG. 5 is a diagram showing a node connection network based on a backbone network optical transmission system according to an embodiment of the present invention.

[0090] FIG. 5 shows an example topology in which a plurality of backbone optical transmission systems (10) form a national-level backbone. Each circle shown in FIG. 5 corresponds to one backbone optical transmission system (10), and Node 1 (511), Node 2 (512), and Node 3 (513) are arranged in the upper row, Node 3 (513), Node 4 (514), and Node 5 (515) are arranged in the right column, Node 5 (515), Node 6 (516), and Node 7 (517) are arranged in the lower row, and Node 1 (511), Node 8 (518), and Node 7 (517) are arranged in the left column.

[0091] An additional cross-link is formed between the left middle node 8 (518) and the right middle node 4 (514) to provide multiple paths. Each node includes an optical transmission processing device (20) and a communication inspection device (40), and the communication inspection device (40) is equipped with a communication status monitoring module and a communication failure response module.

[0092] In the topology of FIG. 5, the backbone network optical transmission system (10) exchanges data through light paths between adjacent nodes. For example, the primary path between Node 1 (511) and Node 3 (513) can be set as an upper path passing through Node 2 (512), and an alternative path between the same ends can be set as an intermediate path reaching Node 3 (513) by passing through Node 8 (518) and Node 4 (514) in sequence from Node 1 (511). For communication from Node 7 (517) to Node 5 (515), a path passing through Node 6 (516) in the lower path can be used as the primary path, and an alternative path can be set to bypass the upper or intermediate path through the left column and the right column. The selection and switching of each path are automatically determined by the communication failure response module.

[0093] The communication inspection device (40) of each backbone network optical transmission system (10) periodically collects observations measured from adjacent links. Examples of observations include optical signal power, optical signal-to-noise ratio, bit error rate, signal loss, frame loss, amplifier gain, wavelength drift, and latency, and these observations are stored separately for each link between nodes. The communication status monitoring module preprocesses and normalizes the observations, then maps them to a reference interval or function to calculate a conditional level. The calculated conditional level is used to determine communication failures along with topology reference information, and the judgment result and supporting information are transmitted to the communication failure response module of each node.

[0094] Operations between nodes are performed through the following cooperation procedure. When two adjacent nodes simultaneously report a sudden change in observations for the same link, the communication failure response module analyzes the correlation in a continuous segment centered on that link and classifies the event as a single-node failure, segment failure, or domain failure. For example, if signs of a degraded optical signal-to-noise ratio and an increase in bit error rate are observed in the link between Node 2 (512) and Node 3 (513), the communication failure response module determines the severity by considering the operational context and selects a response scenario based on current network status information. Selectable scenarios may include a scenario to reconfigure the light path to divert traffic from Node 1 (511) to Node 3 (513) via Node 8 (518) and Node 4 (514), a scenario to adjust the amplifier gain between Node 2 (512) and Node 3 (513), and a scenario to mitigate interference by reallocating wavelength resources.

[0095] When the communication failure response module selects lightpath reconfiguration, the communication failure response control unit sequentially transmits control commands to each optical transmission processing unit (20) located at Node 1 (511), Node 8 (518), Node 4 (514), and Node 3 (513). The order of application of the control commands is safely determined according to the dependency relationship graph, and amplifier setting adjustment, wavelength switching, and port activation are performed in a prescribed order. After applying the control commands, the communication inspection device (40) re-measures the monitoring indicators of the corresponding path and adjacent paths to verify whether the target range is satisfied. If the verification is successful, an event record is saved and the operation is terminated. If the verification fails, backup response procedures such as escalating to a higher intensity scenario, full rollback, partial rollback, or alternate path switching are executed. If necessary, transmission speed limits and queue priority adjustments are applied to low-priority services to ensure overall network stability.

[0096] A similar procedure is performed in cases where amplifier performance gradually degrades at Node 4 (514). When an increase in latency and power imbalance are continuously detected in observations of the links between Node 3 (513) and Node 4 (514), and between Node 4 (514) and Node 5 (515), the communication failure response module classifies it as a segment failure, checks the severity, and then selects the response scenario that allows for the fastest recovery by considering the action time limit. If the selected scenario is amplifier gain readjustment, a control command is applied to the optical transmission processing unit (20) of Node 4 (514), and it is verified in post-verification whether the target range is satisfied. If it fails, a bypass switching using the cross-link connecting Node 8 (518) and Node 4 (514) can be automatically performed.

[0097] In this way, in the topology of FIG. 5, each backbone network optical transmission system (10) collects observations in cooperation with neighboring nodes, checks the severity of communication failures, selects a response scenario based on current network status information, applies control commands to the optical transmission processing device (20) of each node according to the selected scenario, verifies the results through re-measurement of monitoring indicators, and performs backup response if necessary. Through such inter-node operations, the continuity of the lightpath is maintained, the radius of impact of failures is minimized, and stable service provision becomes possible even in a national backbone network.

[0098] The foregoing description is merely an illustrative explanation of the technical concept of the embodiments of the present invention, and those skilled in the art to which the embodiments of the present invention pertain will be able to make various modifications and variations within the scope that does not deviate from the essential characteristics of the embodiments of the present invention. Accordingly, the embodiments of the present invention are intended to explain, not limit, the technical concept of the embodiments of the present invention, and the scope of the technical concept of the embodiments of the present invention is not limited by these embodiments. The scope of protection of the embodiments of the present invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the embodiments of the present invention. Explanation of the symbols

[0099] 10: Backbone optical transmission system 20: Optical transmission processing device 30: Traffic data processing unit 40: Communication inspection device

Claims

Claim 1 A method for controlling communication failure response in a backbone network optical transmission system based on ROADM (Reconfigurable Optical Add-Drop Multiplexing), comprising: a monitoring result acquisition step of acquiring a monitoring result including a communication failure determination result and basis information from a communication status monitoring module; a communication failure severity confirmation step of confirming the severity of the communication failure based on a preset operational context; a response action selection step of selecting a response scenario based on the severity and current network status information; and a communication failure response control step of applying a control command to an optical transmission processing device according to the selected response scenario. The method includes a verification and backup response step that verifies the results by remeasuring monitoring indicators after applying the control command and performs an alternative procedure in the event of verification failure, wherein the communication failure severity verification step maps the step value of the communication failure judgment result to a base severity, calculates a corrected severity by applying weights corresponding to an operational context vector including time zone, service level, protection path availability, remaining resource capacity, and equipment status to the base severity, and calculates an action time limit value by referencing service-specific recovery target time and availability target; the response action selection step selects the response scenario based on the corrected severity, the action time limit value, and the current network status information; the communication failure response control step applies the selected response scenario as a multi-stage procedure including pre-verification, partial application, full application, post-verification, and rollback in case of failure, performs a two-phase commit procedure using the acknowledgment commit of the management protocol, automatically reverts to the previous configuration if no response is received within the commit acknowledgment timer or if a pre-set verification condition is not satisfied, models the dependency relationship between the transmission amplifier, wavelength selection switch, transmission network terminal, and packet equipment as a graph, and the optical transmission in a safe order according to the graph Applying control commands to the processing unit,The above safety sequence includes a sequence of pre-adjusting the amplifier output, performing wavelength switching of the ROADM, and then activating the terminal port of the transmission network terminal; the above communication failure response control step includes saving a snapshot prior to the change and performing protection procedures including limiting the change rate, verifying the maintenance window, and verifying access rights; the above verification and backup response step is characterized by automatically escalating to a higher intensity response scenario if the monitoring indicator re-measured after applying the control command does not fall within the target range, and in the event of the escalation failure, sequentially performing full rollback, partial rollback, configuration retry, and alternative path switching according to priority, and stabilizing the network in a stepwise degraded state by applying transmission rate limits and lowering the queue priority of low-importance services according to the service level policy. Claim 2 delete Claim 3 A communication failure response control method according to claim 1, wherein the communication failure severity verification step classifies the communication failure into one of a single node failure, a segment failure, and a domain failure, and determines the scope of application of the communication failure response control step according to the classification result. Claim 4 delete Claim 5 A communication failure response control method according to claim 1, wherein the current network status information comprises at least one of topology information, protection path status, remaining capacity of links and nodes, status of ongoing change operations, and history of pre-failure measures. Claim 6 A communication failure response control method according to claim 1, wherein the response action selection step comprises calculating a multi-target scoring function including reducing recovery time, minimizing the radius of influence, and minimizing the number of configuration changes, and selecting a response scenario in which the score according to the multi-target scoring function is minimized. Claim 7 A communication failure response control method according to claim 6, wherein the response action selection step is characterized by performing a preliminary simulation based on an equipment model and current network status information to estimate the success probability for each scenario, and selecting only scenarios that satisfy a predetermined threshold value or higher as candidates. Claim 8 A communication failure response control method according to claim 6, wherein the response action selection step is characterized by estimating the set of services affected by the selected scenario to calculate the radius of influence, and automatically switching to an alternative scenario if the influence limit is exceeded. Claim 9 A communication failure response control method according to claim 6, further comprising, prior to the communication failure response control step, a preliminary application applied restrictively to a representative node or representative path section, and a step of expanding the scope of application only if success is confirmed. Claim 10 delete Claim 11 delete Claim 12 delete Claim 13 A communication failure response control method according to claim 1, wherein the verification and backup response step stores the result of the action performed according to the application of the response scenario and the replacement procedure, the parameters and grounds used for the selection of the response scenario or the execution of the replacement procedure, and the success or failure history of the action as an event record, searches for similar patterns in the event record to prioritize the selection of a replacement scenario with a high success rate, and adaptively updates at least one policy among a threshold, a weight, and an impact limit using the event record. Claim 14 A communication failure response control device for a backbone network optical transmission system based on ROADM (Reconfigurable Optical Add-Drop Multiplexing), comprising: a monitoring result acquisition unit configured to acquire a monitoring result including a communication failure determination result and basis information from a communication status monitoring module; a communication failure severity verification unit configured to verify the severity of the communication failure based on a preset operational context; a response action selection unit configured to select a response scenario based on the severity and current network status information; and a communication failure response control unit configured to apply a control command to an optical transmission processing device according to the selected response scenario. The system includes a verification and backup response processing unit configured to verify the result by remeasuring monitoring indicators after the application of the control command and to perform an alternative procedure if the verification fails; wherein the communication failure severity verification unit maps the step value of the communication failure judgment result to a basic severity, calculates a corrected severity by applying weights corresponding to an operational context vector including time zone, service class, protection path availability, remaining resource capacity, and equipment status to the basic severity, and calculates an action time limit value by referencing service-specific recovery target time and availability target; wherein the response action selection unit is configured to select the response scenario based on the corrected severity, the action time limit value, and the current network status information; wherein the communication failure response control unit applies the selected response scenario as a multi-stage procedure including pre-verification, partial application, full application, post-verification, and rollback in case of failure, performs a two-phase commit procedure using the confirmation commit of the management protocol, automatically reverts to the previous configuration if no response is received within the commit confirmation timer or if the pre-set verification condition is not satisfied, and graphs the dependency relationship between the transmission amplifier, wavelength selection switch, transmission network terminal, and packet equipment Modeling,A communication failure response control device is configured to apply control commands to the optical transmission processing device in a safe sequence according to the above graph, wherein the safe sequence includes a sequence of pre-adjusting the amplifier output, performing wavelength switching of the ROADM, and then activating the terminal port of the transmission network terminal; wherein the communication failure response control unit is configured to save a snapshot prior to the change and perform protection procedures including limiting the change rate, verifying the maintenance window, and verifying access rights; wherein the verification and backup response processing unit is configured to automatically escalate to a higher intensity response scenario if the monitoring indicator re-measured after applying the control command does not fall within the target range, and in the event of a failure of the escalation, sequentially perform full rollback, partial rollback, configuration retries, and alternative path switching according to the priority, and stabilize the network in a stepwise degraded state by applying transmission rate limits and lowering the queue priority of low-importance services according to a service level policy.

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