Selection device

Abstract

A selection device 10 extracts a spare system of redundant components, mounted but unused components, and components of a spare component storage base as spare component candidates for failed components, and selects, from among the spare component candidates, a component that can be diverted and has the shortest time until a work maintenance person obtains the component and moves to a failed device. The selection device 10 obtains an operation rate of an existing path when the spare system of the redundant components is removed, and determines that diversion is impossible when the obtained operation rate is lower than a target operation rate.

Description

selection device

[0001] This disclosure relates to the selected device.

[0002] Optical transmission equipment accommodates various communication services such as the internet and dedicated lines, and is positioned as a crucial infrastructure network for network services. In particular, Wavelength Division Multiplexing (WDM) equipment uses wavelength division multiplexing technology to transmit and receive signals of tens of terabytes over a single fiber. Since failures in WDM equipment have a significant impact, there is an increasing demand for improved reliability of communication networks.

[0003] In the event of a component failure in an optical transmission device, replacement with a spare part is the common practice. Non-patent document 1 aims to improve the accuracy of the utilization rate calculation by considering the travel time required for maintenance workers to secure spare parts and move them to the faulty device.

[0004] The uptime of various services may be used as a basis for fee refunds in Service Level Agreements (SLAs), and is also used as an indicator to evaluate network reliability.

[0005] Takamoto, et al., "Study on a Method for Improving the Accuracy of Availability Calculation in WDM Systems," IEICE General Conference 2024, B-6-52, March 7, 2024.

[0006] If a service outage occurs when spare parts at a designated spare parts storage location are depleted, it becomes necessary to secure spare parts from other spare parts storage locations. For example, in systems that have been in operation for a long period, the frequent failure of the same part can lead to the depletion of spare parts within a specific area. When spare parts are depleted, it becomes necessary to secure spare parts from other spare parts storage locations in other areas, which presents the challenge of prolonged recovery.

[0007] This disclosure is made in view of the above and aims to shorten recovery time and improve uptime.

[0008] A selection device according to one aspect of the present disclosure is a selection device for selecting a spare part to replace a faulty part of a faulty device, which extracts parts currently in use as a backup system for redundant parts and unused parts as candidates for spare parts for the faulty part, and selects from the candidates for spare parts the part that is reusable and that can be secured by a maintenance worker and moved to the faulty device in the shortest time.

[0009] According to this disclosure, recovery time can be reduced and uptime can be improved.

[0010] Figure 1 is a diagram illustrating an example of calculating the availability rate in an optical transmission system. Figure 2 is a diagram illustrating an example of a redundant optical transmission system. Figure 3 is a diagram illustrating an example of the process from fault occurrence to fault recovery. Figure 4 is a diagram illustrating an example of the configuration of a selection device. Figure 5 is a flowchart illustrating an example of the processing flow of a selection device. Figure 6 is a diagram illustrating an example of the hardware configuration of a selection device.

[0011] The embodiments of this disclosure will be described below with reference to the drawings. As a prerequisite for describing the selected apparatus of this embodiment, the method for calculating the operating rate of the optical transmission system and the process from fault occurrence to fault recovery will be explained.

[0012] [Calculation of Availability] Referring to Figure 1, an example of calculating the availability in an optical transmission system will be explained.

[0013] The optical transmission system comprises multiple optical transmission devices (devices A, B, Y, and Z in the figure), each connected via an optical fiber. Devices A and Z in the figure are endpoint devices, each comprising a transponder function unit, an optical multiplexing / demultiplexing function unit, a path function unit, and an optical amplification function unit. An optical path is established between the transponder function units of the endpoint devices, and a service node is connected to the transponder function unit. Devices B and Y in the figure are relay devices, each comprising a path function unit and an optical amplification function unit. The relay devices are nodes that relay signals between endpoint devices. Note that Figure 1 is an example, and relay devices may not be placed between terminal devices, or one or more relay devices may be placed.

[0014] The operating rate can be calculated by multiplying the operating rates of each optical transmission device passing through the optical path based on the main signal (optical path) that communicates between service nodes. The operating rate of an optical transmission device can be calculated by multiplying the operating rates of each functional unit included in the optical transmission device. That is, the operating rate can be calculated by multiplying the operating rates of each functional unit passing through the optical path.

[0015] Specifically, the operating rate P of the entire optical path in FIG. 1 A～Z is the value obtained by multiplying the operating rates P A [[ID=XX7]] of each device A to Z. The operating rate P B of device A is the value obtained by multiplying the operating rates P Y of each functional unit of device A. Similarly, the operating rate P Z of device B is the value obtained by multiplying the operating rates P A of each functional unit of device B, and the operating rate P A1 of device Y is the value obtained by multiplying the operating rates P A2 of each functional unit of device Y, and the operating rate P A3 of device Z is the value obtained by multiplying the operating rates P A4 of each functional unit of device Z. B of each functional unit of device B, and the operating rate P B1 of each functional unit of device B, and the operating rate P B2 of each functional unit of device B, and the operating rate P B3 of each functional unit of device B, and the operating rate P B4 of device Y is the value obtained by multiplying the operating rates P Y of each functional unit of device Y, and the operating rate P Y1 of each functional unit of device Y, and the operating rate P [[ID=XX8]] of each functional unit of device Y, and the operating rate P Y2 of each functional unit of device Y, and the operating rate P Y3 of each functional unit of device Y, and the operating rate P Y4 of device Z is the value obtained by multiplying the operating rates P Z of each functional unit of device Z, and the operating rate P Z1 of each functional unit of device Z, and the operating rate P Z2 of each functional unit of device Z, and the operating rate P Z3 of each functional unit of device Z, and the operating rate P Z4 of each functional unit of device Z.

[0016] Note that optical fibers and optical connectors are parts that do not require electric drive and have a very low failure rate, so they are excluded from the calculation of the operating rate of the optical path. When including optical fibers and optical connectors in the calculation of the operating rate, their operating rates may be multiplied in the same way.

[0017] Also, as shown in FIG. 2, when an optical switch is connected to a service node and the optical path is configured redundantly with routes a and b, the operating rate P ab is the operating rate P a of route a and the operating rate P [[ID=XX9]] of route b. b, let the operating rate of the optical switch be P SW It can be calculated by the following formula.

[0018] P ab =(1−(1−P a )×(1−P b ))×P SW ×P SW

[0019] When any functional part on route b fails or is removed, the operating rate P ab can be calculated by the following formula.

[0020] P ab =P a ×P SW ×P SW

[0021] The operating rate of the functional part can be calculated by the following formula using the mean time between failures (MTBF) and the mean time to repair (MTTR).

[0022] Operating rate = MTBF÷(MTBF + MTTR)

[0023] MTBF is calculated by accumulating the design values of the components constituting the functional part. Alternatively, MTBF may be calculated using the statistical values of the number of failures and the operating time. MTTR is calculated based on the repair time at the time of failure.

[0024] [Fault recovery operation] Referring to FIG. 3, an example of the process from the occurrence of a fault to its recovery will be described. Assume that a fault occurs in component A of the optical transmission device. When a fault occurs in the optical transmission device, a notice of the fault occurrence is sent to the remote site. The remote site is the site responsible for the maintenance and inspection of the optical transmission system.

[0025] In step S1, at the remote site, after receiving the fault notice, the fault is isolated, the fault location is identified, and an instruction to repair component A is notified to the responsible maintenance operator.

[0026] In step S2, the maintenance worker moves to the spare part storage base and secures the spare part of part A (also referred to as a spare member or a spare machine). The spare part storage base is a base for storing various parts of the optical transmission device. For example, the spare part storage bases exist for each area. When a device within the area fails, the maintenance worker secures the spare part at the designated spare part storage base within the area.

[0027] In step S3, the maintenance worker moves from the spare part storage base to the location of the failed device with the spare part.

[0028] In step S4, after the maintenance worker replaces part A of the failed device with the spare part, the worker checks the normal operation of the device.

[0029] The repair time can be calculated by summing up the time taken for the steps S1 to S4. The repair time varies greatly depending on the time it takes for the maintenance worker to secure the spare part in step S2 and the time it takes for the maintenance worker to move from the spare part storage base to the location of the failed device in step S3. If a failure occurs when the spare parts at the designated spare part storage base are depleted, it is necessary to move to another spare part storage base to secure the spare part, which requires a lot of time for the maintenance worker to move, thus lengthening the repair time.

[0030] Therefore, in this embodiment, parts (functional parts) of the existing device are also used as spare parts. More specifically, among (i) the spare system of redundant parts, (ii) the parts that are mounted but not in use, and (iii) the parts at the spare part storage base, the parts with a short time (the time taken for steps S2 and S3) from securing the part to moving it to the failed device are selected as spare parts.

[0031] Among the above, if a part that is in use as the spare system of redundant parts is removed and diverted as a spare part, the redundancy is lost, resulting in a decrease in the reliability (operation rate) of the existing path. Therefore, when diverting the spare system of redundant parts as a spare part, calculate the operation rate of the existing path where the redundancy is lost, and determine whether the diversion of the part is possible based on whether the operation rate meets the target operation rate.

[0032] Furthermore, unused components can fall into three categories: components that are installed in a device and registered but unused, components that are installed in a device but unregistered, and components installed in an unregistered device. "Registered" means that the component is in a state where it can be monitored and controlled by the monitoring and control system.

[0033] [Configuration of the Selection Device] Referring to Figure 4, an example of the configuration of the selection device 10 in this embodiment will be described. The selection device 10 is a device that, upon input of the location of the faulty device and information on the faulty part, selects an appropriate spare part based on information obtained from each linked system. The selection device 10 comprises a spare part selection unit 11, a reusability determination unit 12, an operating rate calculation unit 13, a travel time calculation unit 14, a spare machine management information database (DB) 15, and an operating rate calculation DB 16.

[0034] The spare parts selection unit 11 inputs the location of the faulty device and information about the faulty part, retrieves information on potential spare parts that could replace the faulty part from the spare equipment management information DB 15, and selects from the spare parts candidates the one that is reusable and has the shortest travel time between locations (the time taken in steps S2 and S3 in Figure 3). If the spare parts candidate is a backup system for a redundant part, the spare parts selection unit 11 determines whether the spare parts candidate is reusable based on the processing results of the reusability determination unit 12 and the operating rate calculation unit 13. If a part is designated as a part to be excluded from selection, the part is excluded from the spare parts candidates. Backup systems for redundant parts and parts that are installed but unused can be designated as parts to be excluded from selection.

[0035] The spare parts selection unit 11 inputs location information of maintenance workers, spare parts candidates, and faulty equipment into the travel time calculation unit 14, obtains the travel time between locations for each spare part candidate, and selects the spare part candidate with the shortest travel time between locations. If there are multiple locations for maintenance workers, the spare parts selection unit 11 may also select a maintenance worker to perform the repair work in addition to the spare parts. If the maintenance worker to perform the repair work is already determined, the spare parts selection unit 11 may select the spare part candidate closest to the location of the faulty equipment.

[0036] The reusability determination unit 12 receives a candidate for a spare part classified as a backup system for redundant components, and refers to the NW information and NW failure information held in the backup equipment management information DB 15 to determine whether the candidate for the spare part is reusable. A candidate for a spare part of the main signal system that, if removed, would cause failure in both the active system route and the backup system route is not reusable. For example, in the case of an optical path that has a faulty component in the backup system route, if removing a candidate for a spare part on the active system route would cause a service failure, then that candidate for the spare part is not reusable. If the candidate for the spare part is a monitoring and control component that does not conduct the main signal, then if the monitoring and control component has a redundant configuration, the monitoring and control component in the backup system can be reusable as a spare part.

[0037] The availability calculation unit 13 receives a candidate for a spare part classified as a backup system for redundant components, and calculates the availability of existing paths if the candidate spare part is removed by referring to the information necessary for availability calculation held in the availability calculation DB 16. If there is an optical path among the existing paths whose availability falls below the target availability, the candidate spare part cannot be repurposed.

[0038] The travel time calculation unit 14 receives location information of the maintenance worker, spare part candidates, and faulty device, and calculates the travel time between locations. For example, the travel time calculation unit 14 uses a travel time calculation function provided by a map service or the like to calculate the travel time from the maintenance worker's current location to the location of the faulty device via the location of the spare part candidate. The travel time calculated by the travel time calculation unit 14 is used when the spare part selection unit 11 selects a nearby spare part candidate, and when the operating rate calculation unit 13 calculates the operating rate of existing paths.

[0039] The backup equipment management information DB 15 is a database that holds information necessary for selecting spare parts. For example, the backup equipment management information DB 15 holds network configuration, network failure information, equipment installation status, backup equipment information, target operating rate, and parts to be excluded from selection.

[0040] The network configuration is information representing the network configuration of an optical transmission system, and includes device registration information and path information. Device registration information is information about the devices used in the optical transmission system. Path information is information about the optical paths built on the optical transmission system. The network configuration is registered by the monitoring and control system.

[0041] Network fault information represents faults occurring in the optical transmission system. Network fault information is registered by the monitoring and control system.

[0042] The device installation status refers to information about unused components that are installed in the device, including, for example, the building and location where the device is installed, and information about the components installed in the device. The device installation status can also be described as information about unused components that are not registered in the monitoring and control system. The device installation status is registered by the construction status confirmation system.

[0043] Spare parts information refers to information about parts held at each spare parts storage location. This spare parts information is registered by the spare parts management system.

[0044] The target availability rate is the standard that existing paths must meet when redundant components are repurposed as spare components, in order to avoid compromising the reliability of the optical transmission system.

[0045] The parts to be excluded from selection are the parts to be excluded from the list of spare parts candidates. For example, you can specify parts that are installed but unused, and that you want to exclude from the list of spare parts candidates because service activation is imminent.

[0046] The target availability rate and components to be excluded from selection are registered by the network operator.

[0047] The availability calculation DB 16 is a database that holds various parameters used to calculate the availability rate. For example, the availability calculation DB 16 holds the MTBF design value for each functional part of the optical transmission device, the number of failures and operating time for each functional part, the average time for fault isolation, the location information of maintenance workers (worker bases), and the average repair time for each functional part.

[0048] The MTBF design values ​​for each functional component of the optical transmission device, along with the number of failures and operating time for each functional component, are used to calculate the MTBF.

[0049] The average time for troubleshooting is the time taken for step S1 in Figure 3.

[0050] The average repair time for each functional part is the time taken in step S4 in Figure 3.

[0051] The location information of the maintenance worker is used by the travel time calculation unit 14 to calculate the time required for step S2 in Figure 3.

[0052] [Operation of the Selection Device] An example of the processing flow of the selection device will be explained with reference to the flowchart in Figure 5. When the network operator inputs information about the location of the faulty device and the faulty component and instructs the selection of a spare component, the selection device 10 executes the processing shown in the flowchart in Figure 5. The network operator may use the selection device 10 when a fault that causes a service interruption occurs and the spare components at the designated spare equipment storage location are depleted.

[0053] In step S11, the spare parts selection unit 11 obtains spare parts candidates by referring to the spare machine management information DB 15. For example, the spare parts selection unit 11 obtains from the spare machine management information DB 15 the same parts as the faulty part, including spare systems of redundant parts, parts that are installed but unused, and parts from spare parts storage locations as spare parts candidates. At this time, spare systems of redundant parts that the reusability determination unit 12 determines are not reusable, and parts designated as parts to be excluded from selection, are excluded from the spare parts candidates. If spare parts exist at a predetermined spare parts storage location, the spare parts selection unit 11 may select the parts from the predetermined spare parts storage location as spare parts.

[0054] In step S12, the spare part selection unit 11 selects the spare part candidate that is closest to the faulty device from among the spare part candidates. For example, for each spare part candidate, the spare part selection unit 11 transmits the location information of the spare part candidate and the faulty device to the travel time calculation unit 14 to obtain the travel time of each spare part candidate and selects the spare part candidate with the shortest travel time.

[0055] If there are multiple maintenance workers, the spare parts selection unit 11 may acquire the travel time between locations for all combinations of maintenance workers and spare parts candidates, and select the combination of maintenance worker and spare parts candidate with the shortest travel time.

[0056] In step S13, the spare parts selection unit 11 determines whether the selected spare parts candidate is a spare system for redundant parts.

[0057] If the selected spare part candidate is not a spare for a redundant part, in step S18, the spare part selection unit 11 notifies the network operator of the selected spare part candidate.

[0058] If the selected spare part candidate is a spare system for redundant parts, in step S14, the operating rate calculation unit 13 calculates the operating rate of all optical paths passing through the device from which the selected spare part candidate is removed.

[0059] In step S15, the spare parts selection unit 11 determines whether or not there are optical paths that fall below the target operating rate.

[0060] If there are optical paths that fall below the target operating rate, in step S16, the spare part selection unit 11 selects the next closest spare part candidate and repeats the process from step S13.

[0061] If there are no optical paths below the target operating rate, in step S17, the spare part selection unit 11 selects a spare part for the part of the device from which the selected spare part candidate was removed that has lost redundancy. In preparation for the case where the part that has lost redundancy fails, the processing from steps S11 to S16 is performed for that part as well, by replacing the location of the failed device with the location of the device that has the part that has lost redundancy, and the failing part with the part that has lost redundancy.

[0062] In step S18, the spare parts selection unit 11 notifies the network operator of the selected spare parts candidates and spare parts for parts that have lost redundancy.

[0063] Furthermore, if the estimated recovery time falls within the SLA limits, unused but installed parts or parts from spare parts storage locations may be prioritized over redundant parts. Specifically, the selection device 10 extracts unused but installed parts and parts from spare parts storage locations as spare part candidates, calculates the travel time between locations for each spare part candidate, and calculates the recovery time if the faulty part is replaced with the spare part candidate with the shortest travel time. If the calculated recovery time meets the SLA, the selection device 10 selects that part as a spare part.

[0064] As described above, the selection device 10 of this embodiment extracts spare parts from redundant components, installed but unused components, and components from spare parts storage locations as candidates for spare parts for a faulty component. From these candidates, it selects the component that is reusable and that can be secured by a maintenance worker and moved to the faulty device in the shortest time. This makes it possible to shorten the recovery time even if the spare parts at the designated spare parts storage location are depleted.

[0065] The selection device 10 determines the operating rate of the existing path when the spare system of the redundant component is removed, and if the determined operating rate falls below the target operating rate, it determines that the component cannot be repurposed. This allows for the selection of the optimal spare component while minimizing the impact on the existing path.

[0066] The selection device 10 described above can be a general-purpose computer system, such as the one shown in Figure 6, which includes a central processing unit (CPU) 901, memory 902, storage 903, communication device 904, input device 905, and output device 906. In this computer system, the selection device 10 is realized when the CPU 901 executes a predetermined program loaded onto the memory 902. This program can be recorded on a computer-readable non-temporary recording medium such as a magnetic disk, optical disk, or semiconductor memory, or it can be distributed via a network.

[0067] 10 Selection device 11 Spare parts selection unit 12 Reusability determination unit 13 Operating rate calculation unit 14 Travel time calculation unit 15 Spare machine management information DB 16 Operating rate calculation DB

Claims

1. A selection device for selecting a spare part to replace a faulty part of a faulty device, wherein the device extracts parts currently being used as a backup system for redundant parts and unused parts as candidates for spare parts for the faulty part, and selects from among the candidates for spare parts the part that is reusable and can be secured by a maintenance worker and moved to the faulty device in the shortest time.

2. A selection device according to claim 1, wherein the device determines the operating rate when the component currently in use is removed, and determines that the component is unsuitable for repurposing if the determined operating rate falls below a target value.

3. A selection device according to claim 1, which selects from among the spare part candidates a part that is reusable and is closest to the faulty device.

4. A selection device according to claim 1, wherein, when a component currently in use is selected, a second spare component is selected for a component whose redundancy is lost by removing the component currently in use.

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