Availability ratio calculation device

Abstract

An availability ratio calculation device (1) comprising: an availability ratio calculation database (10) that stores in advance a parameter related to a fault isolation time, a parameter related to a securing time of a spare component, a parameter related to a movement time to a failed device, a parameter related to a repair time of the failed device, and an MTBF of a functional unit; and an availability ratio calculation processing unit (14) that calculates an MTTR on the basis of each parameter of the availability ratio calculation database (10), and calculates an availability ratio on the basis of the MTBF and the MTTR having been calculated.

Description

Availability calculation device

[0001] The present invention relates to an availability calculation device for calculating the availability of an optical transmission system.

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

[0003] A method for evaluating the reliability of a transmission system using availability is known (Non-Patent Documents 1 and 2). Availability is expressed by the following formula (1). MTBF (Mean Time Between Failure) is defined as the mean time between failures, and can be calculated using the failure rate of various components that make up the functional units of a transmission device. MTTR (Mean Time To Repair) is defined as the mean time to repair, and can be calculated using the time it takes for a communication carrier to carry out maintenance and operation work when a failure occurs. Availability = MTBF ÷ (MTBF + MTTR) ... (1)

[0004] "MTBF, MTTR, Availability," Nikkei XTECH, October 11, 2006, [online], [Retrieved January 31, 2024], Internet, <URL: https: / / xtech.nikkei.com / it / article / COLUMN / 20060920 / 248547 / > "Will increasing the availability of the entire system increase if we increase the number of devices?", Nikkei XTECH, March 8, 2019, [online], [Retrieved January 31, 2024], Internet, <URL: https: / / xtech.nikkei.com / atcl / nxt / column / 18 / 00617 / 022600006 / >

[0005] In conventional technology, MTBF can be accurately calculated from the failure rates of various components that make up the functional units of a transmission device. On the other hand, MTTR is calculated from past failure history, making it difficult to obtain an accurate value in the case of a new construction or when the number of failures is small. Furthermore, MTTR may fluctuate in the future, in which case an accurate value cannot be obtained from past failure history. Therefore, the above-mentioned conventional technology has the problem of making it difficult to calculate an availability rate with high accuracy.

[0006] Therefore, an object of the present invention is to provide an availability calculation device that can calculate an availability rate with high accuracy.

[0007] In order to solve the above-mentioned problems, the availability calculation device of the present invention is an availability calculation device that calculates the availability of transmission equipment provided in an optical transmission system using MTBF and MTTR, and is characterized by comprising: an availability calculation database that pre-stores parameters related to the time required to isolate a fault, a parameter related to the time required to secure spare parts, a parameter related to the time required to travel to the fault-occurring equipment, and a parameter related to the time required to repair the fault-occurring equipment, as well as the MTBF of a functional unit of the transmission equipment; and an availability calculation processing unit that calculates the MTTR based on the parameters in the availability calculation database, and calculates the availability based on the calculated MTTR and the MTBF in the availability calculation database.

[0008] According to the present invention, the availability rate can be calculated with high accuracy.

[0009] FIG. 1 is a diagram for explaining calculation of an availability rate of an optical transmission system according to an embodiment. FIG. 2 is a diagram for explaining a process from failure occurrence to equipment recovery according to an embodiment. FIG. 3 is a block diagram showing a configuration of an availability rate calculation device according to an embodiment. FIG. 4 is a flowchart showing optical path setting processing according to an embodiment. FIG. 5 is a flowchart showing detour communication path setting processing according to an embodiment. FIG. 6 is a flowchart showing DB information update processing for availability rate calculation according to an embodiment. FIG. 7 is a flowchart showing spare part optimization processing according to an embodiment.

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments described below are intended to embody the technical concept of the present invention, and unless otherwise specified, the present invention is not limited to the following. Furthermore, the same means will be given the same reference numerals, and their description may be omitted.

[0011] As a premise for explaining the availability calculation device according to the embodiment, a method for calculating the availability of the optical transmission system 9 and a process from the occurrence of a failure to the recovery of the equipment will be explained in order.

[0012] [Calculation of Availability in Optical Transmission System] Fig. 1 is a diagram for explaining calculation of availability of an optical transmission system 9 according to an embodiment. As shown in Fig. 1, the optical transmission system 9 is a general transmission network that uses wavelength multiplexing technology. For example, the optical transmission system 9 includes an end point device 90 as a transmission device 90. Ａ and relay device 90 Ｂ and relay device 90 Ｙ and the endpoint device 90 Ｚ The optical transmission system 9 may also include a device control system 99 (FIG. 3) that performs various controls on the transmission device 90.

[0013] End point device 90 Ａ and endpoint device 90 Ｚ is a device located at the end point of the optical transmission system 9. For example, Ａ and endpoint device 90 Ｚ A service node (not shown) is connected to the relay device 90. Ｂ and relay device 90 Ｙ is the endpoint device 90 Ａ and the endpoint device 90 Ｚ It is a node that relays between

[0014] End point device 90 Ａ and relay device 90 Ｂ is an optical communication line 92 such as an optical fiber. Ａ The relay device 90 is connected via the relay device 90. Ｂ and relay device 90 Ｙ is an optical communication line 92 Ｂ The relay device 90 is connected via the relay device 90. Ｙ and endpoint device 90 Ｚis an optical communication line 92 Ｃ That is, the optical transmission system 9 includes a relay device 90 Ｂ and relay device 90 Ｙ and relays the signal to the endpoint device 90 Ａ and the endpoint device 90 Ｚ An optical path 93 is set to connect the above.

[0015] End point device 90 Ａ 9 includes a transponder function unit 91 as a function unit 91 for constructing an optical path 93. Ａ１ and an optical multiplexing / demultiplexing function unit 91 Ａ２ and the path function unit 91 Ａ３ and the optical amplification function unit 91 Ａ４ The relay device 90 Ｂ , relay device 90 Ｙ and endpoint device 90 Ｚ Regarding the endpoint device 90 Ａ It has the same configuration as above.

[0016] The availability of the optical transmission system 9 is determined by the availability P Ａ～Ｚ In addition, the availability rate P Ａ～Ｚ can be calculated by multiplying the availability of each functional unit 91 included in each transmission device 90 that passes through the optical path 93 .

[0017] Specifically, the availability rate P of the optical path 93 Ａ～Ｚ is the endpoint device 90 Ａ Operating rate P Ａ and relay device 90 Ｂ Operating rate P Ｂ and relay device 90 Ｙ Operating rate P Ｙ and the endpoint device 90 Ｚ Operating rate P Ｚ The value is the product of multiplication of the above. Ａ Operating rate P Ａ The transponder function unit 91 Ａ１ Operating rate P Ａ１ and an optical multiplexing / demultiplexing function unit 91 Ａ２ Operating rate P Ａ２ and the path function unit 91 Ａ３ Operating rate P Ａ３ and the optical amplification function unit 91 Ａ４ Operating rate PＡ４ The value is obtained by multiplying the value of the relay device 90 by the value of ... relay device 90. Ｂ Operating rate P Ｂ , relay device 90 Ｙ Operating rate P Ｙ and endpoint device 90 Ｚ Operating rate P Ｚ Regarding the endpoint device 90 Ａ Operating rate P Ａ can be calculated in the same way.

[0018] Note that optical fibers and optical connectors are excluded from the calculation of the availability rate because they do not require electrical drive and the failure rate is extremely small. If the availability rates of optical fibers and optical connectors are taken into account, these availability rates should also be multiplied in the same way.

[0019] Also, consider a case where two optical paths a and b are configured as redundant paths. In this case, the availability rate P ａ and the availability rate P of optical path b ｂ Then, the availability rate P ａｂ is expressed by the following formula (2): ａｂ = (1-(1-P ａ ) × (1-P ｂ )) ... (2)

[0020] [Process from Failure Occurrence to Equipment Recovery] FIG. 2 is a diagram illustrating the process from failure occurrence to equipment recovery in an embodiment. As shown in FIG. 2, consider a case where a component 900A of a transmission device 90 fails. In step S0, a remote base 94 is notified that a failure has occurred in the transmission device 90. The remote base 94 is a base that performs maintenance and inspection of the transmission device 90 in a remote location. In step S1, the remote base 94 isolates the failure and instructs a local maintenance worker 95 to repair the component 900A. In step S2, the maintenance worker 95 travels to a spare parts storage base 96 and secures a spare part 910A for the component 900A. The spare parts storage base 96 is a base that stores spare parts 910A and 910B. In step S3, the maintenance worker 95 travels to the transmission device 90 where the failure has occurred. Hereinafter, the transmission device where the failure has occurred may be abbreviated as the failed device. In step S4, the maintenance worker 95 replaces the broken part 900A with a spare part 910A.

[0021] As described above, MTTR means the mean time to repair and is highly dependent on various maintenance conditions. In particular, MTTR varies significantly depending on the relative positions of the spare parts storage base 96 and the transmission device 90. That is, MTTR varies significantly depending on the time it takes for the maintenance worker 95 to travel to the spare parts storage base 96 in step S2 and the time it takes for the maintenance worker 95 to travel to the failed device in step S3. In this way, the travel time of the maintenance worker 95 is a major variable in MTTR. Therefore, a more accurate MTTR can be calculated by taking the travel time of the maintenance worker 95 into consideration.

[0022] [Configuration of Availability Calculation Device] Fig. 3 is a block diagram showing the configuration of an availability calculation device 1 according to an embodiment. The availability calculation device 1 calculates the availability of a transmission device 90 included in an optical transmission system 9 using MTBF and MTTR. As shown in Fig. 3, the availability calculation device 1 includes an availability calculation DB (database) 10, a NW (network) configuration management information DB 11, a spare part location optimization information storage DB 12, a travel time calculation processing unit 13, an availability calculation processing unit 14, a route calculation processing unit 15, a path setting / device control unit (communication route setting processing unit) 16, a spare part optimization processing unit 17, and a fault notification analysis unit 18.

[0023] <Availability Calculation DB> The availability calculation DB 10 is a database that stores in advance information necessary for calculating the availability. The availability calculation DB 10 stores parameters related to the time required to isolate a failure, a parameter related to the time required to secure spare parts, a parameter related to the time required to travel to the failed device, a parameter related to the time required to repair the failed device, and the MTBF of the functional unit 91 of the transmission device 90. For example, a NW operator 97 updates each parameter in the availability calculation DB 10, which will be described below.

[0024] Specifically, the availability calculation DB 10 stores the average time to isolate a failure as a parameter related to the time to isolate a failure. The availability calculation DB 10 stores the location of a maintenance worker and the location of a spare part as parameters related to the time required to secure a spare part. The availability calculation DB 10 stores the location of a transmission device as a parameter related to the time required to travel to a failed device. The availability calculation DB 10 stores the average time to repair a functional part as a parameter related to the time required to repair a failed device.

[0025] The MTBF of a functional unit is information indicating the MTBF of each functional unit 91 constituting each transmission device 90 provided in the optical transmission system 9. For example, in the endpoint device 90 of FIG. Ａ In this case, the MTBF of the function is the transponder function 91 Ａ１ MTBF, optical multiplexing / demultiplexing function unit 91 Ａ２ MTBF, route function unit 91 Ａ３ MTBF and optical amplification function unit 91Ａ４ represents the MTBF of the relay device 90 Ｂ , relay device 90 Ｙ and endpoint device 90 Ｚ The same applies to the MTBF of the functional part.

[0026] The location of spare parts is information indicating the location where spare parts necessary for repairing parts corresponding to each functional unit 91 are stored. For example, the location of spare parts indicates the location of the spare parts storage base 96 in FIG. 2 .

[0027] The location of the maintenance worker is information indicating the location of the maintenance worker in the optical transmission system 9. For example, the location of the maintenance worker indicates the location of the base where the maintenance worker 95 in FIG. 2 is waiting.

[0028] The location of the transmission device is information indicating the location of each transmission device 90 provided in the optical transmission system 9. For example, the location of the transmission device is the location of the end point device 90 in FIG. Ａ Position of relay device 90 Ｂ Position of relay device 90 Ｙ and the position of the end point device 90 Ｚ Represents the position of.

[0029] The mean repair time of a functional unit is information representing the mean repair time of each functional unit 91 constituting each transmission device 90 provided in the optical transmission system 9. The mean repair time of a functional unit may be estimated from the history of maintenance work. For example, Ａ In this case, the transponder function unit 91 Ａ１ Average repair time for the optical multiplexing / demultiplexing function unit 91 Ａ２ Average repair time of the route function unit 91 Ａ３ and the mean repair time of the optical amplification function unit 91 Ａ４ represents the average repair time (relay device 90 Ｂ , relay device 90 Ｙ and endpoint device 90 Ｚ also applies).

[0030] The mean time to isolate a fault is the average time required for the remote site 94 to isolate the location of the fault. The mean time to isolate a fault may be estimated from the history of maintenance work.

[0031] <NW Configuration Management Information DB> The NW configuration management information DB 11 is a database that stores information related to the network configuration of the optical transmission system 9. Specifically, the NW configuration management information DB 11 stores the NW configuration, NW fault information, the availability of transmission devices, the target availability of optical paths, and the availability of optical paths.

[0032] The NW configuration is information that indicates the network configuration of the optical transmission system 9. For example, a NW operator 97 registers the network configuration such as the optical path 93 and the detour communication path of the optical path 93.

[0033] The NW fault information is information indicating whether or not a fault has occurred in the optical transmission system 9. For example, the alarm monitoring system 98 updates the NW fault information when it notifies of a fault.

[0034] The availability of the transmission device is information indicating the availability of each transmission device 90 provided in the optical transmission system 9. In the example of FIG. 1, the availability of the transmission device is Ａ Operating rate P Ａ , relay device 90 Ｂ Operating rate P Ｂ , relay device 90 Ｙ Operating rate P Ｙ , and the endpoint device 90 Ｚ Operating rate P Ｚ For example, the availability calculation processing unit 14 updates the availability of the transmission device.

[0035] The target availability of the optical path is information indicating the target availability of each optical path 93 set in the optical transmission system 9. For example, the NW operator 97 registers the target availability of the optical path.

[0036] The optical path availability is information indicating the availability of each optical path 93 set in the optical transmission system 9. For example, the route calculation processing unit 15 updates the optical path availability.

[0037] <DB for storing spare part location optimization information> The DB for storing spare part location optimization information 12 is a database that stores optimized positions of spare parts. The DB for storing spare part location optimization information 12 stores optimized positions of spare parts so as to further improve the availability calculated using the positions of spare parts in the DB for calculating availability 10. For example, the NW operator 97 sets the positions of spare parts in the DB for calculating availability 10 by referring to the positions of spare parts stored in the DB for storing spare part location optimization information 12.

[0038] <Travel time calculation processing unit> The travel time calculation processing unit 13 uses a point-to-point travel time search service to calculate the time it takes for the maintenance worker 95 to secure a spare part from the location of the maintenance worker and the location of the spare part, and the time it takes for the maintenance worker 95 to travel to the faulty device from the location of the spare part and the location of the faulty device.

[0039] That is, the travel time calculation processing unit 13 refers to the locations of the maintenance workers and the spare parts in the availability calculation DB 10, and calculates the travel time to the spare parts storage base 96 shown in step S2 of Fig. 2. The travel time calculation processing unit 13 refers to the locations of the spare parts and the failed equipment in the availability calculation DB 10, and calculates the travel time to the failed equipment shown in step S3 of Fig. 2.

[0040] The travel time calculation processing unit 13 calculates the travel time using a point-to-point travel time search service. The travel time search service is a service that allows users to search for the travel time between two desired points (for example, Reference 1).

[0041] Reference 1: Google Maps, [online], [searched January 31, 2024], Internet, <URL: https: / / www.google.co.jp / maps / >

[0042] The travel time calculation processing unit 13 outputs the calculation results, ie, the time it takes for the maintenance worker to secure the spare part and the time it takes for the maintenance worker to travel to the faulty device, to the availability calculation processing unit 14 .

[0043] <Availability Calculation Processor> The availability calculation processor 14 calculates the MTTR based on the parameters in the availability calculation DB 10, and calculates the availability based on the calculated MTTR and the MTBF in the availability calculation database.

[0044] Specifically, the availability calculation processing unit 14 acquires the mean time to isolate a failure and the mean time to repair a functional unit from the availability calculation DB 10. The availability calculation processing unit 14 receives the time it takes for a maintenance worker to secure spare parts and the time it takes for the maintenance worker to travel to the failed unit from the travel time calculation processing unit 13. The availability calculation processing unit 14 then calculates the MTTR as the sum of the mean time to isolate a failure, the time it takes for the maintenance worker to secure spare parts, the time it takes for the maintenance worker to travel to the failed unit, and the mean time to repair a functional unit.

[0045] The availability calculation processing unit 14 acquires the MTBF of the functional unit from the availability calculation DB 10. The availability calculation processing unit 14 then calculates the availability of each transmission device 90 based on the calculated MTTR and the MTBF acquired from the availability calculation DB 10. The method for calculating the availability of the transmission device 90 is as described above with reference to equation (1) and FIG. 1.

[0046] The availability calculation processor 14 stores the calculated availability of each transmission device 90 in the NW configuration management information DB 11 .

[0047] In this embodiment, when the NW operator 97 updates the availability calculation DB 10, the availability calculation device 1 calculates the availability in the above-described procedure (<3> Update of availability calculation DB information). Note that the timing of calculating the availability is not limited to when the NW operator 97 updates the availability calculation DB 10, and is arbitrary.

[0048] <Route computation processing unit> The route computation processing unit 15 calculates the availability of the optical path 93 of the optical transmission system 9 based on the availability calculated by the availability calculation processing unit 14, and calculates the optical path 93 and a detour communication path. Specifically, the route computation processing unit 15 acquires the availability of the transmission devices 90 that configure the optical path 93 and the detour communication path, and calculates the availability of the optical path 93 and the detour communication path. The method for calculating the availability of the optical path 93 is as described above using equation (1) and in FIG. 1.

[0049] The route computation processing unit 15 calculates the optical path 93 and the detour communication route based on the availability of the optical path 93 and the detour communication route. The route computation processing unit 15 outputs the calculated optical path 93 and the detour communication route to the path setting / device control unit 16. The route computation processing unit 15 also stores the calculated optical path 93 and the detour communication route and their availability in the NW configuration management information DB 11.

[0050] <Path Setting / Device Control Unit> The path setting / device control unit 16 sets an optical path 93 and a detour communication route in the optical transmission system 9 based on the calculation result of the route calculation processing unit 15. The path setting / device control unit 16 sets the optical path 93 and the detour communication route input from the route calculation processing unit 15 to the transmission device 90 and the device control system 99 of the optical transmission system 9.

[0051] In this embodiment, the availability calculation device 1 sets the optical path 93 in accordance with the above-described procedure (<1> Optical path setting) in response to an instruction from the NW operator 97. Furthermore, when the fault notification analysis unit 18 updates the NW fault information in the NW configuration management information DB 11, the availability calculation device 1 sets a detour communication path for the optical path 93 in accordance with the above-described procedure (<2> Fault notification: detour communication path setting).

[0052] <Spare part optimization processing unit> The spare part optimization processing unit 17 changes the location of a spare part to one of a plurality of predetermined bases, and repeatedly causes the availability calculation processing unit 14 to calculate the availability for each changed location of the spare part. The spare part optimization processing unit 17 then optimizes the location of the spare part so as to maximize the calculated availability.

[0053] In this embodiment, when the NW configuration management information DB11 is updated, the availability calculation device 1 optimizes the placement of spare parts (<4> Spare part placement optimization). Specifically, when any of the NW configuration, NW fault information, transmission device availability, optical path target availability, or optical path availability in the NW configuration management information DB11 is updated, the availability calculation device 1 optimizes the placement of spare parts. The spare part optimization processing unit 17 stores the optimized positions of spare parts in the spare part position optimization information storage DB12.

[0054] <Fault Notification Analysis Unit> The fault notification analysis unit 18 analyzes a fault notification from the alarm monitoring system 98 and updates the NW fault information in the NW configuration management information DB 11 .

[0055] [Operation of Availability Calculation Device] <Lightpath Setting Process> Fig. 4 is a flowchart showing the lightpath setting process in the embodiment. As shown in Fig. 4, in step S10, the NW operator 97 sets the optical path 93 at point A (for example, the end point device 90 in Fig. 2). Ａ ), the Z point of the optical path 93 (for example, the end point device 90 in FIG. 2) Ｚ ), and the target availability rate of the optical path 93 are registered in the NW configuration management information DB 11 .

[0056] In step S11, the route calculation processing unit 15 calculates, as a candidate communication route, an optical path 93 having end points at point A and point Z. For example, if there are different candidate communication routes from point A to point Z, the route calculation processing unit 15 calculates all candidate communication routes.

[0057] In step S12, the route calculation processing unit 15 calculates the availability of the communication route candidates. For example, if there are multiple communication route candidates that are different from each other, the route calculation processing unit 15 calculates the availability of all the communication route candidates.

[0058] In step S13, the route calculation processing unit 15 determines whether or not there is a candidate communication route whose availability rate is equal to or higher than the target availability rate.

[0059] If there is a candidate communication path whose availability is equal to or greater than the target availability (Yes in step S13), the availability calculation device 1 proceeds to the process of step S14.

[0060] If there is no candidate communication path with an availability rate equal to or higher than the target availability rate (No in step S13), the availability calculation device 1 ends the optical path setting process.

[0061] In step S14, the route calculation processing unit 15 determines whether there are multiple candidates for communication routes that meet the determination condition of step S13. That is, the route calculation processing unit 15 determines whether there are multiple candidates for communication routes that have an availability rate equal to or higher than the target availability rate.

[0062] If there are multiple candidates for communication paths with availability rates equal to or higher than the target availability rate (Yes in step S14), the availability calculation device 1 proceeds to the process of step S16.

[0063] If there are no candidates for communication paths with an availability rate equal to or higher than the target availability rate (No in step S14), the availability calculation device 1 proceeds to the process of step S15.

[0064] In step S15, since there is only one candidate communication path, the route calculation processing unit 15 outputs it to the path setting / device control unit 16 as the optical path 93. The path setting / device control unit 16 sets the optical path 93 calculated by the route calculation processing unit 15 to the transmission device 90. Thereafter, the availability calculation device 1 ends the optical path setting process.

[0065] In step S16, since there are multiple candidates for the communication route, the route calculation processing unit 15 selects the optical path 93 with the highest availability.

[0066] In step S17, the route calculation processing unit 15 outputs the optical path 93 selected in step S16 to the path setting / device control unit 16. The path setting / device control unit 16 sets the optical path 93 selected by the route calculation processing unit 15 to the transmission device 90. Thereafter, the availability calculation device 1 ends the optical path setting process.

[0067] 5 is a flowchart showing the process of setting up a detour communication path according to an embodiment. As shown in FIG. 5, in step S20, the fault notification analysis unit 18 analyzes the fault notification from the alarm monitoring system 98 and updates the NW fault information in the NW configuration management information DB 11.

[0068] In step S21, the failure notification analysis unit 18 determines the failed section of the optical path 93 where the signal is affected from the contents of the failure notification.

[0069] In step S22, the route calculation processing unit 15 calculates candidates for communication routes (detour communication routes) that bypass the failed section of the optical path 93 determined in step S21.

[0070] In step S23, the route calculation processing unit 15 calculates the availability of candidates for the detour communication route. For example, if there are multiple different detour communication routes, the route calculation processing unit 15 calculates the availability of all candidates for the detour communication route.

[0071] In step S24, the route calculation processing unit 15 determines whether or not there is a candidate for an alternative communication route that has an availability rate equal to or higher than the target availability rate.

[0072] If there is a candidate for an alternative communication path that has an availability rate equal to or higher than the target availability rate (Yes in step S24), the availability calculation device 1 proceeds to the process of step S26.

[0073] If there is no candidate for an alternative communication path with an availability rate equal to or higher than the target availability rate (No in step S24), the availability calculation device 1 proceeds to the process of step S25.

[0074] In step S25, the NW operator 97 checks the availability of the detour communication path and decides whether to detour the optical path 93 where the failure has occurred. If the optical path 93 is to be detoured, the NW operator 97 manually sets the detour communication path. Thereafter, the availability calculation device 1 ends the detour communication path setting process.

[0075] In step S26, the route calculation processing unit 15 determines whether or not there are multiple candidates for the detour communication route that meet the determination condition of step 24. In other words, the route calculation processing unit 15 determines whether or not there are multiple candidates for the detour communication route that have an availability rate equal to or higher than the target availability rate.

[0076] If there are multiple candidates for the alternative communication path that have an availability rate equal to or higher than the target availability rate (Yes in step S26), the availability calculation device 1 proceeds to the process of step S28.

[0077] If there are no multiple candidates for the alternative communication path that have an availability rate equal to or higher than the target availability rate (No in step S26), the availability calculation device 1 proceeds to the process of step S27.

[0078] In step S27, since there is only one candidate for the detour communication path, the route calculation processing unit 15 outputs it as the detour communication path to the path setting / device control unit 16. The path setting / device control unit 16 sets the detour communication path calculated by the route calculation processing unit 15 in the transmission device 90. Thereafter, the availability calculation device 1 ends the detour communication path setting process.

[0079] In step S28, since there are multiple candidates for the alternative communication route, the route calculation processing unit 15 selects the alternative communication route with the highest availability rate.

[0080] In step S29, the route calculation processing unit 15 outputs the detour communication route selected in step S28 to the path setting / device control unit 16. The path setting / device control unit 16 sets the detour communication route selected by the route calculation processing unit 15 in the transmission device 90. Thereafter, the availability calculation device 1 ends the detour communication route setting process.

[0081] 6 is a flowchart showing the process of updating information in the DB for operating rate calculation in the embodiment. As shown in FIG. 6, in step S30, the NW operator 97 updates each parameter in the DB for operating rate calculation 10.

[0082] In step S31, the travel time calculation processing unit 13 refers to the availability calculation DB 10 and uses a point-to-point travel time search service to calculate the travel time to the spare parts storage base 96 and the travel time to the failed device.

[0083] In step S32, the availability calculation processing unit 14 calculates the MTTR as the sum of the mean time to isolate a failure and the mean time to repair a functional unit in the availability calculation DB 10, the travel time to the spare parts storage base 96, and the travel time to the failed device.The availability calculation processing unit 14 then calculates the availability of the transmission device 90 based on the calculated MTTR and the MTBF in the availability calculation DB 10.

[0084] In step S33, the availability calculation unit 14 stores the availability of the transmission device 90 calculated in step S32 in the NW configuration management information DB 11.

[0085] <Spare Parts Optimization Processing> Fig. 7 is a flowchart showing the spare parts optimization processing in the embodiment. As shown in Fig. 7, in step S40, the NW configuration management information DB 11 is updated.

[0086] The spare part optimization processing unit 17 changes the location of the spare part to one of the preset spare part storage bases and repeats the calculation of the availability rate in steps S41 to S45. At this time, the NW operator 97 sets in advance the spare part storage bases that may store the location of the spare part. That is, in steps S41 to S45, the spare part optimization processing unit 17 repeatedly calculates the availability rate for all patterns in which the spare part storage base where the spare part is stored is changed.

[0087] In step S42, the spare part optimization processing unit 17 determines whether or not there are any spare part positions that have not been calculated.

[0088] If there are spare part positions that have not yet been calculated (Yes in step S42), the availability calculation device 1 proceeds to the process of step S43.

[0089] If there are no spare part positions that have not yet been calculated (No in step S42), the availability calculation device 1 proceeds to the process of step S46.

[0090] In step S43, the spare part optimization processing unit 17 changes the spare part positions to those that have not yet been calculated.

[0091] In step S44, the spare part optimization processing unit 17 causes the availability calculation processing unit 14 to calculate the availability of the optical path 93 at the spare part position changed in step S43.

[0092] In step S46, the spare part optimization processing unit 17 determines whether there is an optical path 93 among the existing optical paths 93 whose operating rate is lower than the target operating rate, and whether there is a spare part position such that the operating rates of all optical paths 93 calculated in step S44 exceed the target operating rate.

[0093] If the location of the corresponding spare part exists (Yes in step S46), the availability calculation device 1 proceeds to the process of step S47.

[0094] If there is no corresponding spare part location (No in step S46), the availability calculation device 1 proceeds to the process of step S48.

[0095] In step S47, the spare part optimization processing unit 17 stores the spare part positions calculated in step S46 in the spare part position optimization information storage DB 12.

[0096] In step S48, the spare part optimization processing unit 17 determines whether there are any spare part locations that exceed the availability rates of all existing optical paths 93. At this time, the importance of the optical paths 93 and the equipment installation bases may be set in advance, and the locations of spare parts may be determined so that the availability rate of the optical path 93 with the highest importance is maximized. Alternatively, the spare part optimization processing unit 17 may prioritize an optical path 93 with a higher target availability rate than other optical paths 93, and determine the placement of spare parts so that the availability rate of that optical path 93 is maximized. Note that if there are multiple spare part locations that exceed the availability rates of all existing optical paths 93, the determination method is not limited to these two methods.

[0097] If the location of the corresponding spare part exists (Yes in step S48), the availability calculation device 1 proceeds to the process of step S49.

[0098] If there is no corresponding spare part position (No in step S48), the availability calculation device 1 ends the spare part optimization process.

[0099] In step S49, the spare part optimization processing unit 17 stores the spare part positions calculated in step S48 in the spare part position optimization information storage DB 12. Thereafter, the availability calculation device 1 ends the spare part optimization process.

[0100] [Effect] The availability calculation device 1 according to the embodiment calculates the availability of a transmission device 90 provided in an optical transmission system 9 using MTBF and MTTR, and is characterized by comprising: an availability calculation DB 10 that pre-stores parameters related to the time required to isolate a fault, a parameter related to the time required to secure spare parts, a parameter related to the time required to travel to the fault-occurring device, and a parameter related to the time required to repair the fault-occurring device, as well as the MTBF of a functional unit 91 of the transmission device 90; and an availability calculation processing unit 14 that calculates the MTTR based on the parameters in the availability calculation DB 10, and calculates the availability based on the calculated MTTR and the MTBF in the availability calculation database.

[0101] According to the above configuration, the availability calculation device 1 can calculate a more accurate MTTR by taking into account maintenance conditions such as the travel time of the maintenance worker 95, which is a major variable in MTTR. As a result, the availability calculation device 1 can calculate an availability with high accuracy.

[0102] The availability calculation DB 10 stores the average time to isolate a failure as a parameter related to the time to isolate a failure, stores the location of a maintenance worker and the location of the spare part as parameters related to the time to secure a spare part, stores the location of the failed device as a parameter related to the time to travel to the failed device, and stores the average time to repair a functional part as a parameter related to the time to repair the failed device, and is equipped with a travel time calculation processing unit that uses a travel time search service between two points to calculate the time it takes for a maintenance worker to secure a spare part from the location of the maintenance worker and the location of the spare part, and the time it takes for the maintenance worker to travel from the location of the spare part and the location of the failed device to the failed device, and the availability calculation processing unit 14 calculates the MTTR as the sum of the average time to isolate the failure, the time it takes for the maintenance worker to secure the spare part, the time it takes for the maintenance worker to travel to the failed device, and the average time to repair the functional part.

[0103] According to the above configuration, the availability calculation device 1 can accurately calculate the travel time of the maintenance worker 95 from the location of the maintenance worker, the location of the spare part, and the location of the failed device stored in the availability calculation DB 10. As a result, the availability calculation device 1 can accurately calculate the MTTR.

[0104] The optical transmission system further includes a route calculation processing unit 15 that calculates the availability of the optical path 93 of the optical transmission system 9 based on the availability calculated by the availability calculation processing unit 14, and calculates the optical path 93 and a detour communication route, and a path setting / device control unit 16 that sets the optical path 93 and a detour communication route in the optical transmission system 9 based on the calculation result of the route calculation processing unit 15.

[0105] According to the above configuration, the availability calculation device 1 can set the optical path 93 and the detour communication path based on the accurately calculated availability, thereby improving the reliability of the optical transmission system 9.

[0106] The system further comprises a spare part optimization processing unit 17 that changes the location of the spare part to any one of a plurality of preset bases, repeats the process of having the availability calculation processing unit 14 calculate the availability for each changed location of the spare part, and optimizes the location of the spare part so as to maximize the calculated availability.

[0107] According to the above configuration, the availability calculation device 1 allows the NW operator 97 to grasp the optimal location of spare parts. As a result, by reviewing the placement of spare parts, the operator can review the placement of spare parts so that the availability of existing optical paths can be increased.

[0108] (Modifications) Although the embodiments have been described above in detail, the present invention is not limited to the above-described embodiments, and includes design modifications and the like within the scope of the present invention.

[0109] In the above embodiment, the availability calculation DB stores the locations of the maintenance workers, the spare parts, and the faulty equipment. However, this is not limited to this. For example, the time required to secure the spare parts and the time required to travel to the faulty equipment may be calculated in advance, and the calculated time required to secure the spare parts and the time required to travel to the faulty equipment may be stored in the availability calculation DB.

[0110] In the above embodiment, the optical paths and the detour communication paths are set based on the calculated availability, but the method of using the availability is not particularly limited. For example, the calculated availability may be used to estimate the traffic volume of the optical transmission system or to evaluate the reliability of the optical transmission system.

[0111] In the above-described embodiment, the availability calculation device is described as independent hardware, but the present invention is not limited to this. For example, the present invention can also be realized by a program that causes hardware resources such as a CPU, memory, and hard disk of a computer to function as the availability calculation device. This program may be distributed via a communication line or written to a recording medium such as a CD-ROM or flash memory.

[0112] REFERENCE SIGNS LIST 1 Availability calculation device 10 Availability calculation DB 11 Network configuration management information DB 12 Spare part location optimization information storage DB 13 Travel time calculation processing unit 14 Availability calculation processing unit 15 Route calculation processing unit 16 Path setting / device control unit (communication route setting processing unit) 17 Spare part optimization processing unit 18 Failure notification analysis unit

Claims

1. An availability calculation device that uses MTBF and MTTR to calculate the availability of transmission equipment provided in an optical transmission system, comprising: an availability calculation database that pre-stores parameters related to the time required to isolate a failure, a parameter related to the time required to secure spare parts, a parameter related to the time required to travel to the failed equipment, and a parameter related to the time required to repair the failed equipment, as well as the MTBF of a functional unit of the transmission equipment; and an availability calculation processing unit that calculates the MTTR based on the parameters in the availability calculation database, and calculates the availability based on the calculated MTTR and the MTBF in the availability calculation database.

2. The availability calculation database according to claim 1, wherein the database stores a mean time to isolate a failure as a parameter related to the time to isolate the failure, stores the location of a maintenance worker and the location of the spare part as parameters related to the time to secure the spare part, stores the location of the transmission equipment as a parameter related to the time to travel to the failure-occurring device, and stores the mean time to repair the functional unit as a parameter related to the time to repair the failure-occurring device, and comprises a travel time calculation processing unit that uses a travel time search service between two points to calculate the time it takes for the maintenance worker to secure the spare part from the location of the maintenance worker and the location of the spare part, and the time it takes for the maintenance worker to travel to the failure-occurring device from the location of the spare part and the location of the failure-occurring device, wherein the availability calculation processing unit calculates the MTTR as the sum of the mean time to isolate the failure, the time it takes for the maintenance worker to secure the spare part, the time it takes for the maintenance worker to travel to the failure-occurring device, and the mean time to repair the functional unit.

3. The availability calculation device according to claim 1, further comprising: a route calculation processing unit that calculates the availability of optical paths in the optical transmission system based on the availability calculated by the availability calculation processing unit, and calculates the optical paths and detour communication routes; and a communication route setting processing unit that sets the optical paths, communication routes, and detour communication routes in the optical transmission system based on the calculation results of the route calculation processing unit.

4. The availability calculation device according to claim 1, further comprising a spare part optimization processing unit that changes the location of the spare part to one of a plurality of predetermined bases, repeats the process of having the availability calculation processing unit calculate the availability for each changed location of the spare part, and optimizes the location of the spare part so as to maximize the calculated availability.

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