OTN network service fault recovery method and system

Abstract

The invention belongs to the technical field of OTN optical network routing computing, and particularly relates to an OTN network service fault recovery method and system. The method comprises the following steps: establishing a first objective function, and setting a first constraint condition for the first objective function; determining an available path of a to-be-recovered service based on the first objective function; establishing a second objective function based on the available path of the to-be-recovered service, and setting a second constraint condition for the second objective function; and based on the second target function, determining a target path of a to-be-recovered service, and performing fault recovery for the target path. According to the method, the two-stage model of the fault network is accurately constructed, and the calculation complexity can be remarkably reduced through the two-stage model.

Description

Technical Field

[0001] The present invention belongs to the technical field of OTN optical network routing calculation, and in particular relates to an OTN network service fault recovery method and system. Background Art

[0002] After the OTN network is built, network failures often occur during the operation of the network, such as node power failure and link interruption. These failures can basically be converted into link failures. For example, after a node loses power, all links connected to the node are also unavailable. Therefore, a node failure can be converted into a failure of all links connected to the node. After a link failure, the service passing through the link will be interrupted. How to quickly restore the service route and minimize the customer's poor perception?

[0003] In the field of optical communication transmission, the spectrum range of the C-band is usually 196.675 Thz to 190.675 Thz, while the spectrum range of the L-band is 190.325 Thz to 184.325 Thz. With the breakthrough of optical devices, L-band channels can also successfully transmit optical signals, which requires the adaptation of the C+L-band routing algorithm. There is a 0.35 Thz interval between the C-band and the L-band. How to unify discontinuous channels is one of the differences between C+L-band routing calculation and C-band routing calculation. In addition, the optical amplifier has different effects on amplifying signals in the C-band and L-band, and the optical signal-to-noise ratio of each channel needs to be considered separately.

[0004] This disclosure focuses on the service routing recovery problem of OTN network. With the continuous breakthroughs made by scientific and technological personnel in the transmission capacity of optical communications, the current transmission capacity has expanded from the C band to the C+L band, and may be expanded to the full S+C+L band in the future. Currently, it is in the early trial stage of C+L. The breakthrough in transmission capacity has also brought new challenges to the service routing recovery of the optical transmission network. For example, optical modules, relays and other equipment cannot fully support the C and L bands at the same time; in the recovery network, the multiplexing of the relay can only be used by the business that occupied the relay before the failure occurred; the channel of the business in the scenario where the failure did not occur cannot be used by other recovery services in the recovery scenario, etc. Summary of the invention

[0005] In view of the above problems, the present disclosure provides an OTN network service fault recovery method, the method comprising:

[0006] Establishing a first objective function, and setting a first constraint condition for the first objective function;

[0007] Based on the first objective function, determining an available path for the service to be restored;

[0008] Establishing a second objective function based on the available path of the service to be restored, and setting a second constraint condition for the second objective function;

[0009] Based on the second objective function, a target path of the service to be restored is determined, and fault recovery is performed on the target path.

[0010] Preferably, establishing the first objective function comprises:

[0011] Obtain path data in the fault network;

[0012] The path data are weighted and summed to obtain the first objective function.

[0013] Preferably, the path data in the faulty network includes: the number of services successfully restored in the faulty network, the total length or total number of links, the number of newly added relays, and the number of reduced relays.

[0014] Preferably, the first constraint condition includes: source and sink node constraint, path connectivity constraint, anti-loop constraint, osnr constraint, link wavelength constraint and relay quantity constraint on the node.

[0015] Preferably, the source-destination node constraints include: only one of all links of the target service from the target source point meets the requirement; only one of the links of the target service to all the destination nodes meets the requirement;

[0016] The path connectivity constraints include: each subpath of the target service is a link that ends and is connected; the hth subpath and the h+1th subpath of the target service are links that end and are connected; the number of services entering the subpath is consistent with the number of links exiting the subpath;

[0017] The anti-loop constraint includes: the number of links entering the target node is less than or equal to one; the number of links leaving the target node is less than or equal to one;

[0018] The osnr constraints include: the OSNR attenuation values ​​of the C band and the L band in the target service meet the threshold requirements;

[0019] The link wavelength constraint includes: the number of services passing through each link is less than the number of channels supported by the link; the number of services passing through the C band of the target link is less than the number of spectrums of the C channel on the link; the number of services passing through the L band of the target link is less than the number of spectrums of the L channel on the link;

[0020] The constraint on the number of relays on the node includes: the reusable relays on the target node can only be used for the services that originally occupied the relays before the failure.

[0021] Preferably, after constructing the first constraint condition for the coefficients in the first objective function, the method further includes:

[0022] Determine whether the coefficients in the first objective function satisfy the first constraint condition;

[0023] If not satisfied, add a relay in the node.

[0024] Preferably, determining the variable when the source and sink port of the pth sub-path of the target service is the io path wavelength w and the variable when the source and sink port of the pth sub-path of the target service is the r relay;

[0025] The variables when the source and sink ports of the pth subpath of the target service are r relays are weighted and summed with the variables when the source and sink ports of the pth subpath of the target service are io and the path wavelength is w to obtain the second objective function.

[0026] Preferably, the second constraint condition includes: source-sink constraint, relay point constraint, local group constraint at both ends of the relay, relay constraint, relay available wavelength constraint, local group wavelength usage constraint, link wavelength usage constraint.

[0027] Preferably, the source-destination constraints include: the target service has only one path or no path starting from the target point; the target service has only one path or no path back to the target point;

[0028] The relay point constraint includes: the number of m-1 sub-paths of the target service is the same as the number of the m-th sub-path; the relays of the o local group of the sub-path m-1 of the target service and the i local group of the sub-path m are the same;

[0029] The local group constraints at both ends of the relay include: the local groups at both ends of the relay cannot be the same;

[0030] The relay constraints include: each relay can only be used once;

[0031] The wave constraints available to the relay include: each relay can only use the wave available to the relay;

[0032] The local group wavelength usage constraint includes: each wavelength in the local group can only be used once;

[0033] The link wavelength usage constraint includes: each wavelength of the link can only be used once.

[0034] The present disclosure also provides an OTN network service fault recovery system, the system comprising:

[0035] A first establishing module, used for establishing a first objective function and setting a first constraint condition for the first objective function;

[0036] A first determining module, configured to determine an available path for the service to be restored based on the first objective function;

[0037] A second establishing module, used to establish a second objective function based on the available path of the service to be restored, and set a second constraint condition for the second objective function;

[0038] The second determination module is used to determine a target path of the service to be restored based on the second objective function, and perform fault recovery on the target path.

[0039] The present disclosure has the following beneficial effects:

[0040] (1) The present disclosure accurately constructs a two-stage model of the fault network, which can significantly reduce the computational complexity;

[0041] (2) The linear programming solver in the present disclosure can give accurate results in small planning scenarios, provide the optimal solution for the company's centralized procurement verification in small planning scenarios, and enhance the company's overall competitiveness; while achieving the maximum service recovery rate, it can ensure a significant reduction in the number of relays;

[0042] (3) The present disclosure simplifies the OSNR model so that the OSNR value of the service path can be linearized. The linear model is the prerequisite for accurately solving the problem.

[0043] Other features and advantages of the present disclosure will be described in the following description, and partly become apparent from the description, or be understood by implementing the present disclosure. The purpose and other advantages of the present disclosure can be realized and obtained by the structures indicated in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 A diagram showing an OTN network service failure recovery method in an embodiment of the present disclosure is shown;

[0046] Figure 2 A schematic diagram of an optical transmission network in an embodiment of the present disclosure is shown;

[0047] Figure 3 A diagram of an OTN network service failure recovery system in an embodiment of the present disclosure is shown;

[0048] Figure 4A diagram of an OTN network service failure recovery device in an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0049] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as being limited to the examples set forth herein; on the contrary, these embodiments are provided so that the present disclosure will be more comprehensive and complete, and the concepts of the example embodiments are fully conveyed to those skilled in the art. The described features, structures, or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced while omitting one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, known technical solutions are not shown or described in detail to avoid obscuring various aspects of the present disclosure.

[0050] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or implemented in one or more hardware units or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0051] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the steps. For example, some steps may be decomposed, while some steps may be combined or partially combined, so the actual execution order may change according to the actual situation.

[0052] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example.

[0053] In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or sub-modules is not necessarily limited to those steps or sub-modules explicitly listed, but may include other steps or sub-modules not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0054] The technical problem to be solved by the present disclosure is: given an optical transmission network, represented by (N, E), N is the set of nodes, and E is the set of links. n∈N represents a node in the network, which is an optical add-drop multiplexing node. The optical service is transmitted to the local group through the line port of the node, and then the local group is connected to the remote group, and the remote group is connected to the remote group of other nodes; (i, j)∈E represents the link between node i and node j. The link here is an optical fiber link, specifically, the remote group of node i is connected to the remote group of node j. The optical signal propagates in the optical fiber. The optical fiber channel can transmit a limited spectrum of light. The mature optical signal is the C+L band optical signal, which may be expanded to the S+C+L band in the future; t k ∈T represents an optical service in the optical transmission network, and T is the set of all services in the network. In the absence of a fault, the paths and resources of all services are determined. When a link failure occurs, the services on these links will be interrupted, and the paths and resources for these services need to be recalculated. The goal is to restore the services in the current faulty network as much as possible, with the least number of newly added relays and the least number of multiplexed relays. In the faulty network, the services that need to be restored are determined, and t k Indicates the service k that needs to be restored in the faulty network; irj indicates that there is a reusable relay r on node i. If r = 0, it means a new relay is added. When light is transmitted in the optical fiber channel, signal attenuation occurs, and the attenuation values ​​of the C channel and the L band are different. For each link (i, j), the attenuation value clf can be used. ij To represent the attenuation of the C band, llf ij The attenuation of the L band is represented by |w. A path is composed of links that are connected end to end and do not form a loop. Its attenuation value can be represented by the cumulative sum of the attenuation values ​​of the links passing through this path. The spectrum width in each optical fiber is limited, and |w ij | represents the number of C+L channels in the link, where |W Cik | represents the amount of spectrum available in the C-band, |W lij | represents the amount of spectrum available in the L band. The number of services on each link cannot exceed the channel resources on the link; the channel set in the C channel range is represented by W Cij To represent, the channel set of L channel range is represented by W Lij To represent. Each spectrum resource in each chain can only be occupied by one service. It is necessary to recalculate the path and resources for each service to be restored. The path is a set of links that are connected end to end and not in a loop. It is also necessary to allocate the original line interface, channel, and relay for the service. All restoration services should be considered together to restore the service as much as possible, with as few new relays as possible and as few multiplexed relays as possible.

[0055] In addition, it is necessary to consider that when a service is not faulty, its line ports, local groups and relays cannot be used by other services when they are restored after the fault. For this service, its resources include its own resources when it is not faulty and resources not used by other services.

[0056] The technical solution adopted by the present disclosure to solve the above technical problems is: first construct an accurate data model of the problem in two stages. In the first stage, a model is established to solve the accurate path and whether these paths have sufficient relay, local group, and wavelength resources. The first stage model is solved by a linear programming solver to calculate the path of each faulty service. In the second stage, a distribution model of local groups, relays, and wavelengths for all paths (the paths are calculated in the first stage) is established. The second stage model calculates the local group, relay, and wavelength of each path by calling a linear programming solver.

[0057] The disclosure requires the highest service recovery rate for fiber-broken fault networks, the least number of newly added relays, the least number of hops in the entire network, and the least use of multiplexed relays. This is a multi-objective optimization problem. In order to ensure smooth transmission of services, optical communication networks still have many physical constraints, including:

[0058] 1. An optical channel can only be used by one service. The optical channel here refers to light of a specific frequency.

[0059] 2. Once a certain frequency of light on a link is occupied, the light of that specific frequency cannot be occupied again;

[0060] 3. The connectivity requirement of the service, that is, the path of this service must be connected end to end;

[0061] 4. The business path cannot form a loop;

[0062] 5. The source and sink nodes of the service path must be the source and sink nodes of the service;

[0063] 6. When the optical signal is transmitted in the optical fiber, it will produce a certain attenuation. When the optical signal is attenuated below the OSNR threshold, it must be converted into optical and electrical signals through the relay to restore the signal. Therefore, the service also needs to meet the OSNR constraint;

[0064] 7. The number of relays on each node is limited, so the number of relays added to a node cannot exceed the maximum number of relays on the node; there are many other constraints, such as whether relays can pass through the same local group at the same time; the number of relays occupied by the original route of the service can only be restored and used by the service itself, and cannot be used by other services; the number of newly added relays on different fault networks can be reused; constraints containing a certain resource can also be added, etc.

[0065] In view of the above objectives and constraints, the present invention establishes an accurate mathematical model, and tries to establish the mathematical model as an integer linear programming model. For the integer linear programming model, the exact solution of the problem in the small programming case can be calculated through a linear programming solver, such as Cplex, Gurobi, etc. When the scale of the problem is further expanded, an approximate solution to the problem will be obtained through some heuristic or approximate algorithms.

[0066] like Figure 1 As shown, the present disclosure proposes an OTN network service failure recovery method, the method comprising:

[0067] Establishing a first objective function, and setting a first constraint condition for the first objective function;

[0068] Based on the first objective function, determining an available path for the service to be restored;

[0069] Establishing a second objective function based on the available path of the service to be restored, and setting a second constraint condition for the second objective function;

[0070] Based on the second objective function, a target path of the service to be restored is determined, and fault recovery is performed on the target path.

[0071] Specifically, establishing the first objective function includes:

[0072] Obtain path data in the fault network;

[0073] The path data are weighted and summed to obtain the first objective function.

[0074] Specifically, the path data in the faulty network includes: the number of services successfully restored in the faulty network, the total length or total number of links, the number of newly added relays, and the number of reduced relays.

[0075] Specifically, the first constraint conditions include: source and sink node constraints, path connectivity constraints, anti-loop constraints, osnr constraints, link wavelength constraints and relay quantity constraints on nodes.

[0076] Specifically, the source and sink node constraints include: only one of all links of the target service from the target source point meets the requirement; only one of the links of the target service to all sink nodes meets the requirement;

[0077] The path connectivity constraints include: each subpath of the target service is a link that ends and is connected; the hth subpath and the h+1th subpath of the target service are links that end and are connected; the number of services entering the subpath is consistent with the number of links exiting the subpath;

[0078] The anti-loop constraint includes: the number of links entering the target node is less than or equal to one; the number of links leaving the target node is less than or equal to one;

[0079] The osnr constraints include: the OSNR attenuation values ​​of the C band and the L band in the target service meet the threshold requirements;

[0080] The link wavelength constraint includes: the number of services passing through each link is less than the number of channels supported by the link; the number of services passing through the C band of the target link is less than the number of spectrums of the C channel on the link; the number of services passing through the L band of the target link is less than the number of spectrums of the L channel on the link;

[0081] The constraint on the number of relays on the node includes: the reusable relays on the target node can only be used for the services that originally occupied the relays before the failure.

[0082] Specifically, after constructing the first constraint condition for the coefficients in the first objective function, the method further includes:

[0083] Determine whether the coefficients in the first objective function satisfy the first constraint condition;

[0084] If not satisfied, add a relay in the node.

[0085] Specifically, the establishing of the second objective function based on the available paths of the services to be restored includes:

[0086] Determine the variables when the source and sink ports of the p-th sub-path of the target service are io paths with wavelength w and the variables when the source and sink ports of the p-th sub-path of the target service are r relays;

[0087] The variables when the source and sink ports of the pth subpath of the target service are r relays are weighted and summed with the variables when the source and sink ports of the pth subpath of the target service are io and the path wavelength is w to obtain the second objective function.

[0088] Specifically, the second constraint condition includes: source-destination constraint, relay point constraint, local group constraint at both ends of the relay, relay constraint, relay available wavelength constraint, local group wavelength usage constraint, and link wavelength usage constraint.

[0089] Specifically, the source-destination constraints include: the target service has only one path or no path starting from the target point; the target service has only one path or no path back to the target point;

[0090] The relay point constraint includes: the number of m-1 sub-paths of the target service is the same as the number of the m-th sub-path; the relays of the o local group of the sub-path m-1 of the target service and the i local group of the sub-path m are the same;

[0091] The local group constraints at both ends of the relay include: the local groups at both ends of the relay cannot be the same;

[0092] The relay constraints include: each relay can only be used once;

[0093] The wave constraints available to the relay include: each relay can only use the wave available to the relay;

[0094] The local group wavelength usage constraint includes: each wavelength in the local group can only be used once;

[0095] The link wavelength usage constraint includes: each wavelength of the link can only be used once.

[0096] This method solves the technical problem in two steps:

[0097] Step 1: Path and resource calculation (this step does not distinguish resources, only calculates the satisfiability of resources)

[0098] Objective function:

[0099]

[0100] Among them, t k Indicates whether the new path of service k can be restored;

[0101] ∑ k t k Indicates the number of services successfully restored in a faulty network;

[0102] Co is expressed as a constant, which is used to adjust whether the service recovery rate can dominate other weight indicators;

[0103] r represents a reusable relay on the source node of link ij, which is consistent with the band of service k. For Reg of work type, only the corresponding service can be used;

[0104] R k Indicates the relay set that can be reused by service k, and the relays in the relay set are consistent with the original band of the service;

[0105] Indicates the total length or total number of hops of the link;

[0106] P indicates whether the total length of the new route used to adjust the service recovery can dominate other weight indicators;

[0107] Indicates the number of newly added relays;

[0108] M is used to adjust whether the number of newly added relays can dominate other weight indicators;

[0109] It is represented as follows: superscript k is the service index; h is the hth subpath on the service path, a subpath represents an optical channel, and the wavelengths of all links on this optical channel are consistent; irj represents a link ij through which the service route passes, and r represents the relay on the i node; a=1 means that link ij is the first subpath, and a=0 means it is not the first; b=1 means the last link of the link subpath, and b=0 means it is not the last link;

[0110] It means to use as few relays as possible;

[0111] N indicates whether using as few multiplexing relays as possible can dominate other weight indicators.

[0112] Because the priority here is always to ensure that business recovery is the most important principle, the Co value needs to be greater than the maximum value of the sum of P, M and N. The above formula is a multi-objective function. The final strategy can be changed by adjusting different weights. For example, if you want to reduce the number of new relays, then M can be set to 0.

[0113] Constraints (network e generated for each broken fiber link):

[0114] Source and sink node constraints:

[0115]

[0116] It means that only one of all the links (s, j) from source point s of service k meets the requirements;

[0117] In the formula, R k It is represented as a relay set that can be reused by service k, and the relays in the relay set are consistent with the original band of the service;

[0118]

[0119] It means that among all the links (i, d) from service k to sink node d, only one meets the requirement.

[0120] Path connectivity constraints:

[0121]

[0122] Each subpath h of service k must be composed of links connected end to end. If a service passes through link (i,n), the next link must be (n,j), that is, the link with n as the starting point.

[0123]

[0124] For service k, the hth subpath and h+1th subpath must be end-to-end links. The last link of the hth subpath is (i,n), and the first link of the next subpath h+1 must be the link (n,j) with n as the source node.

[0125]

[0126] For all services to be restored, for each h sub-path, the number of services entering the h sub-path and the number of links exiting the h sub-path are consistent.

[0127] Anti-looping constraints

[0128]

[0129] For a service to be restored, there can be at most one link that enters the node n;

[0130]

[0131] For a service to be restored, there can be at most one link with n nodes.

[0132] The above two constraints can constrain a business to pass through only one same node at most.

[0133] Osnr constraints:

[0134]

[0135] For C-band services, the OSNR attenuation value of the C-band needs to meet the threshold requirement;

[0136] Where Clf ij Expressed as the loss factor of link ij in the C-band.

[0137]

[0138] For L-band services, the OSNR attenuation value of the L-band needs to meet the threshold requirement;

[0139] In the formula, Llf ij Expressed as the loss factor of link ij in the L band.

[0140]

[0141] Since the reverse attenuation of the link may be different from that of the forward attenuation, the reverse OSNR threshold of the C wave is constrained at the same time.

[0142]

[0143] Since the reverse attenuation of the link may be different from that of the forward direction, the reverse OSNR threshold of the L wave is constrained at the same time.

[0144] The above four constraints indicate that the path of service k must meet the OSNR threshold Threshold. If it does not meet this requirement, it is necessary to consider adding a relay in the middle.

[0145] Link wavelength constraints:

[0146]

[0147] The number of services passing through each link is less than the number of channels that can be supported on the link;

[0148] Where W ij Denote the set of available channels for link ij.

[0149]

[0150] The number of all C-band services passing through link (i, j) must be less than the number of C-channel spectra on the link;

[0151] In the formula, K C Indicates the C-band service set;

[0152] W Cij Represents the set of available channels in the C band on link ij.

[0153]

[0154] The number of all L-band services passing through link (i, j) must be less than the number of L-channel spectra on the link;

[0155] In the formula, K L Indicates the L-band service set;

[0156] W Lij It is represented as the set of available channels in the L band on link ij.

[0157] Relay quantity constraints on a node:

[0158] Reusable

[0159] For the reusable relay r on node i, only the services that originally occupied the relay before the failure can use it, and other services to be restored cannot use the relay.

[0160] Not reusable

[0161] For the relay released by other services on node i, except for being used by itself, other services cannot use the relay.

[0162] You can also add inclusion and exclusion constraints in the first step. The inclusion problem is an NP-hard problem in path planning, but in integer linear programming, it is a linear constraint.

[0163] Step 2: Allocate resources (local group, relay, wavelength) to the path calculated in step 1

[0164] Objective function:

[0165] Maximize:

[0166] Where i represents the local group of the source node of the path p, o represents the local group of the destination node of the path p, and the variable includes two parts: 1. local group index; 2. service available relay index;

[0167] w represents the wavelength on this path;

[0168] k represents the kth business;

[0169] p indicates that the path calculated in the first step is a subpath that is connected end to end and does not form a cycle;

[0170] i=r means that node i uses relay r;

[0171] W k : The set of wavelengths that can be used by service k. Considering that services cannot use the original wavelength resources (local groups, links) of other services, the wavelength w used by service k k , w k ∈W k ;

[0172] The variable representing the source and sink ports of the p-th sub-path of target service k when the wavelength of the io path is w. If the condition is met, it is 1, otherwise it is 0;

[0173] The variable representing the case where the source and sink ports of the p-th subpath of target service k are relays r. If the condition is met, the value is 1; otherwise, the value is 0.

[0174] Source and sink constraints:

[0175]

[0176] The above formula indicates that for the path p, starting from the node s, there can be only one or no path, and the number cannot exceed 1, which means that business k has only one path or no path starting from point s.

[0177]

[0178] The above formula indicates that service k has only one path or no path back to point d.

[0179] Relay point constraints:

[0180]

[0181] The above formula indicates that the service k has multiple subpaths, and the number of the m-1th subpath is the same as the number of the m-1th subpath, that is, the number of the m-1th subpath is the same as the number of the m-th subpath. If there is an m-1 subpath but no m subpath, then this path will lack m subpaths. So the number must be the same.

[0182]

[0183] The above formula indicates that relays are added between multiple sub-paths. The relays are placed on two local groups, that is, the relays of the o local group of sub-path m-1 and the i local group of sub-path m are both r. A relay r consists of two local groups, the outgoing and incoming.

[0184] The local groups at both ends of the relay cannot be the same:

[0185]

[0186] Each relay can only be used once:

[0187]

[0188] Where W r It is represented as the set of channels that can be used by relay r.

[0189] Each relay can only use the waves available to that relay:

[0190]

[0191] Each wavelength in a local group can be used only once:

[0192]

[0193] Each wavelength of a link can only be used once (l:link):

[0194]

[0195] Finally, an integer linear programming solver, such as Cplex, Gurobi, etc., is called to calculate available paths for services to be restored in the faulty network, and the resources (local groups, relays, and wavelengths) of these paths are sufficient in quantity.

[0196] Example

[0197] like Figure 2 As shown, given an optical transmission network, there are seven nodes: ABCDEFG, and eleven links: AB, AC, BD, BE, CD, CF, DE, EG, FG, DG1 ( Figure 2 Center left), DG2( Figure 2 The number of channels available on each link is marked. Figure 2 As shown, the service matrix and the occupied paths and link channel resources are as follows:

[0198] AE has 10 100G services, passing through ACDGE, DG is DG1, and the services are recorded as s1-s 10 , accounting for 1-10 waves;

[0199] DG has 10 100G services, which pass through DG1 and are recorded as s 11 -s 20 , accounting for waves 51-60;

[0200] BG has 10 100G services, passing through BDG, DG is DG2, and the service is recorded as s 21 -s 30 , accounting for waves 31-40;

[0201] FB has 10 100G services, passing through FGDB, DG is DG1, and the service is recorded as s 31 -s 40 , accounting for 41-50 waves;

[0202] The steps are as follows:

[0203] (1) For the above network, there are 11 links, and 40 services either pass through DG1 or DG2. When both DG1 and DG2 fail, all 40 services need to be recalculated;

[0204] (2) Build a model based on the objectives and constraints of the first step,

[0205]

[0206] For the network above, P is set to 1, M is 500, N is 250, and Co is 1;

[0207] Call Gurobi to calculate the path. The first step of recovery calculates the path as follows:

[0208] s1-s 10 For services, the recovery path is AC and CFGE, which is divided into two parts, indicating that a relay needs to be added at point C;

[0209] s 11 -s 20 Business, the recovery path is DEG;

[0210] s 21 -s 30 For services, the recovery path is BD and DEG, which is divided into two sections, indicating that a relay needs to be added at point D;

[0211] s 31 -s 40 Business, the restoration path is FGEB;

[0212] (3) The path has been calculated in the first step. The second step is to allocate line ports, local groups and relays for the above path. The objective function of the second step is:

[0213] Maximize:

[0214] Here the coefficient M is set to 4.

[0215] (4) Call Gurobi to calculate the path resources. The result of the second step is

[0216] s1-s 10 Service, the restoration path is AC and CFGE, the AC channel is 1-10, and the CFGE channel is 1-10

[0217] s 11 -s 20 For services, the recovery path is DEG, and the channels of DEG are 41-50;

[0218] s 21 -s 30 For services, the recovery paths are BD and DEG, the BD channels are 31-40, and the DEG channels are 31-40;

[0219] s 31 -s 40 The service restoration path is FGEB, the channels are 76-80, 5 services are restored, and the remaining 5 services are lost.

[0220] like Figure 3 As shown, the present disclosure also proposes an OTN network service fault recovery system, the system comprising:

[0221] A first establishing module, used for establishing a first objective function and setting a first constraint condition for the first objective function;

[0222] A first determining module, configured to determine an available path for the service to be restored based on the first objective function;

[0223] A second establishing module, used to establish a second objective function based on the available path of the service to be restored, and set a second constraint condition for the second objective function;

[0224] The second determination module is used to determine a target path of the service to be restored based on the second objective function, and perform fault recovery on the target path.

[0225] like Figure 4 As shown, corresponding to the OTN network service fault recovery method provided above, the present disclosure also provides an OTN network C+L optical layer service fault recovery device. Since the embodiment of the device is similar to the above method embodiment, the description is relatively simple. For relevant parts, please refer to the description of the above method embodiment. The device described below is only schematic. The device may include: a processor (processor) 1, a memory (memory) 2 and a communication bus (i.e., the above device bus) and a search engine, wherein the processor 1 and the memory 2 communicate with each other through the communication bus and communicate with the outside through the communication interface. The processor 1 can call the logic instructions in the memory 2 to execute the OTN network service fault recovery method.

[0226] In addition, the logic instructions in the above-mentioned memory 2 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present disclosure is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present disclosure. The aforementioned storage medium includes: a storage chip, a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a disk or an optical disk, and other media that can store program codes.

[0227] On the other hand, an embodiment of the present disclosure further provides a processor-readable storage medium, on which a computer program 3 is stored. When the computer program 3 is executed by the processor 1, the OTN network service failure recovery method provided in the above embodiments is implemented.

[0228] The processor-readable storage medium can be any available medium or data storage device that can be accessed by the processor 1, including but not limited to magnetic storage (such as floppy disks, hard disks, magnetic tapes, magneto-optical disks (MO), etc.), optical storage (such as CD, DVD, BD, HVD, etc.), and semiconductor storage (such as ROM, EPROM, EEPROM, non-volatile memory (NANDFLASH), solid-state drive (SSD)), etc.

[0229] Those skilled in the art should understand that although the present disclosure is described in detail with reference to the aforementioned embodiments, it is still possible to modify the technical solutions recorded in the aforementioned embodiments, or to make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A method for recovering an OTN network service failure, characterized in that: The method comprises: Establishing a first objective function, and setting a first constraint condition for the first objective function; Based on the first objective function, determining an available path for the service to be restored; Establishing a second objective function based on the available path of the service to be restored, and setting a second constraint condition for the second objective function; Based on the second objective function, a target path of the service to be restored is determined, and fault recovery is performed on the target path.

2. The OTN network service failure recovery method according to claim 1, characterized in that: The establishing of the first objective function comprises: Obtain path data in the fault network; The path data are weighted and summed to obtain the first objective function.

3. The OTN network service failure recovery method according to claim 1, characterized in that: The path data in the faulty network includes: the number of services successfully restored in the faulty network, the total length or total number of links, the number of newly added relays, and the number of reduced relays.

4. The OTN network service failure recovery method according to claim 1, characterized in that: The first constraint conditions include: source and destination node constraints, path connectivity constraints, anti-loop constraints, osnr constraints, link wavelength constraints and relay quantity constraints on nodes.

5. The OTN network service failure recovery method according to claim 4, characterized in that: The source and sink node constraints include: only one link of the target service from the target source point meets the requirement; only one link of the target service to all sink nodes meets the requirement; The path connectivity constraints include: each subpath of the target service is a link that ends and is connected; the hth subpath and the h+1th subpath of the target service are links that end and are connected; the number of services entering the subpath is consistent with the number of links exiting the subpath; The anti-loop constraint includes: the number of links entering the target node is less than or equal to one; the number of links leaving the target node is less than or equal to one; The osnr constraints include: the OSNR attenuation values ​​of the C band and the L band in the target service meet the threshold requirements; The link wavelength constraint includes: the number of services passing through each link is less than the number of channels supported by the link; the number of services passing through the C band of the target link is less than the number of spectrums of the C channel on the link; the number of services passing through the L band of the target link is less than the number of spectrums of the L channel on the link; The constraint on the number of relays on the node includes: the reusable relays on the target node can only be used for the services that originally occupied the relays before the failure.

6. The OTN network service failure recovery method according to claim 1, characterized in that: After constructing the first constraint condition for the coefficients in the first objective function, the method further includes: Determine whether the coefficients in the first objective function satisfy the first constraint condition; If not satisfied, add a relay in the node.

7. The OTN network service failure recovery method according to claim 1, characterized in that: The establishing of the second objective function based on the available paths of the service to be restored includes: Determine the variables when the source and sink ports of the p-th sub-path of the target service are io paths with wavelength w and the variables when the source and sink ports of the p-th sub-path of the target service are r relays; The variables when the source and sink ports of the pth subpath of the target service are r relays are weighted and summed with the variables when the source and sink ports of the pth subpath of the target service are io and the path wavelength is w to obtain the second objective function.

8. The OTN network service failure recovery method according to claim 1, characterized in that: The second constraint conditions include: source-destination constraint, relay point constraint, local group constraint at both ends of the relay, relay constraint, relay available wavelength constraint, local group wavelength usage constraint, and link wavelength usage constraint.

9. The OTN network service failure recovery method according to claim 8, characterized in that: The source-destination constraints include: the target service has only one path or no path starting from the target point; the target service has only one path or no path back to the target point; The relay point constraint includes: the number of m-1 sub-paths of the target service is the same as the number of the m-th sub-path; the relays of the o local group of the sub-path m-1 of the target service and the i local group of the sub-path m are the same; The local group constraints at both ends of the relay include: the local groups at both ends of the relay cannot be the same; The relay constraints include: each relay can only be used once; The wave constraints available to the relay include: each relay can only use the wave available to the relay; The local group wavelength usage constraint includes: each wavelength in the local group can only be used once; The link wavelength usage constraint includes: each wavelength of the link can only be used once.

10. An OTN network service fault recovery system, characterized in that: The system comprises: A first establishing module, used for establishing a first objective function and setting a first constraint condition for the first objective function; A first determining module, configured to determine an available path for the service to be restored based on the first objective function; A second establishing module, used to establish a second objective function based on the available path of the service to be restored, and set a second constraint condition for the second objective function; The second determination module is used to determine a target path of the service to be restored based on the second objective function, and perform fault recovery on the target path.

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