WO2012057095A1 - 周波数割当方法および装置 - Google Patents
周波数割当方法および装置 Download PDFInfo
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- WO2012057095A1 WO2012057095A1 PCT/JP2011/074465 JP2011074465W WO2012057095A1 WO 2012057095 A1 WO2012057095 A1 WO 2012057095A1 JP 2011074465 W JP2011074465 W JP 2011074465W WO 2012057095 A1 WO2012057095 A1 WO 2012057095A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
- H04J14/0254—Optical medium access
- H04J14/0256—Optical medium access at the optical channel layer
- H04J14/0257—Wavelength assignment algorithms
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
- H04J14/0254—Optical medium access
- H04J14/0267—Optical signaling or routing
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L45/00—Routing or path finding of packets in data switching networks
- H04L45/62—Wavelength based
Definitions
- the present invention relates to a frequency allocation method and apparatus, and in particular, in a photonic network composed of optical nodes including optical switches that switch an optical signal without being electrically terminated, the optical signal connecting the start point and the end point of the optical signal.
- the present invention relates to a technique for selecting a path of a path and a wavelength used on the path. More specifically, the present invention performs path setting in a photonic network that realizes efficient use of wavelength in an optical path network including an optical path that is switched as light as an optical node, assigns a wavelength, and
- the present invention relates to a frequency allocation method and apparatus applicable even when the widths are different.
- the optical path network that supports the current backbone network is mainly a group of optical communication devices such as a wavelength division multiplexing transmission device, an optical add / drop device, and an optical cross-connect device, and a transmission path group such as an optical fiber that connects them, and It is configured by a path group such as a wavelength for connecting optical communication apparatuses via a transmission path.
- a transparent type optical path network for connecting optical communication apparatuses from end to end of an optical path network without regenerating and repeating optical signals in a relay section is attracting attention.
- One of the problems in such a transparent optical path network is the problem of how to determine a route on the network in response to a traffic transfer request, and which wavelength to assign over the determined route. These are generally referred to as Routing and Wavelength Assignment (RWA) problems.
- RWA Routing and Wavelength Assignment
- a conventional RWA system in a transparent optical path network will be described.
- a route is first determined by a routing process.
- a shortest path algorithm is often used to determine the path.
- FIG. 2 there are a Fewest-hop method, a Shortest-distance method, etc., which are respectively a method for minimizing the number of hops between the end points of a route or a method for minimizing a physical distance. .
- the wavelength is assigned by the first-fit method or the most-used method.
- the first-fit method is a method in which when there are a plurality of wavelength candidates that can be assigned when selecting a wavelength on a certain path, the numbers assigned to the wavelengths are assigned in order from the smallest number.
- the number assigned to the wavelength for example, there is a method of numbering in order from the shortest wavelength. This may be from a long wavelength.
- the most-used method counts the number of wavelengths used in the entire network for each wavelength when there are multiple candidates when selecting wavelengths on a certain route, giving priority to the most used wavelength. (For example, refer nonpatent literature 1).
- the RWA method as described above is expected to realize economic and power saving of the optical path network by effectively utilizing the limited wavelength resources of the transparent optical path network.
- an optical network that flexibly allocates optical frequency resources has been studied. This is because the conventional transparent optical path network allocates frequency resources with a fixed frequency width to the optical path, whereas the network is configured with a variable bandwidth transponder and a variable bandwidth cross-connect, This is an optical communication network that assumes that frequency resources managed by more subdivided slots (grids) are allocated as much as needed in the bandwidth and route of the optical path and resources are used efficiently.
- grids subdivided slots
- wavelength is mainly used in the description of the path having a fixed frequency width
- frequency is mainly used in the description of the path having a variable frequency width.
- the conventional RWA method has the following problems in the case of a transparent optical path network that is not variable in bandwidth and in the case of a transparent optical path network that is variable in bandwidth (hereinafter referred to as a variable bandwidth optical network).
- the first-fit method which is one of the prior arts, searches for available wavelength candidates and simply assigns wavelengths from the one with the smallest wavelength number. A new wavelength is allocated without considering the use situation of the wavelength used in this link. This will be described with reference to FIGS. 3 to 4 by way of example.
- the wavelength usage state can be expressed as shown in FIG.
- the vertical axis represents the wavelength
- the horizontal axis shows adjacent links.
- the allocation is performed regardless of whether the wavelength in the adjacent link is unused through the optical node that is the end point of the allocated wavelength.
- FIG. 4 in this example, after allocation, in these adjacent links, a segmented section occurs when viewed at the allocated wavelength. This is called Fragmentation here.
- Fragmentation here, a network having a simple ring configuration is assumed, and the column in FIG. 4 represents a link between adjacent nodes.
- the Fragmentation occurs even when the Most-used method is used. This is because, when the usage situation of wavelengths is counted over adjacent links that are continuous at each wavelength, the youngest wavelength is the maximum number as in the example of FIG. Therefore, Fragmentation occurs in the same way by the Most-used method.
- variable bandwidth optical network in addition to the restriction of using a common wavelength in the passing path, which has been considered in the past, when allocating a plurality of slots (grids), a continuous frequency region in the fiber is ensured and light is transmitted.
- the need to assign to a path arises (continuous spectrum constraint).
- This is a restriction that has not been assumed in the conventional transparent optical path network in which a fixed wavelength (in other words, a frequency resource having a fixed width) is allocated and operated.
- the conventional wavelength allocation algorithm does not take this restriction into consideration, and therefore a case where frequency resources cannot be allocated efficiently occurs. Therefore, when a path is accommodated in a variable bandwidth optical network by a conventional method, there is a problem that a lot of frequency use fragmentation occurs in a state where frequency resources are not partially used.
- the present invention provides a frequency allocation method and apparatus in a photonic network that can effectively suppress the occurrence of fragmentation in a transparent optical path network and maximize the utilization efficiency of wavelength (frequency) resources. Objective.
- the start point when a start point and an end point of an optical signal are given in a photonic network including an optical node including an optical switch that switches an optical signal without being electrically terminated, the start point There is provided a frequency allocation method for selecting a frequency width to be used on a path connecting the end point and the end point.
- the frequency allocation method is An apparatus comprising: a calculation result storage means for storing a route and frequency calculation result; a router means for performing route calculation and storing the route calculation result in the calculation result storage means; and an assigning means for allocating the frequency width of the network.
- the assigning means is By referring to the path calculation result of the calculation result storage means, the correlation amount of the use state of the wavelength or frequency between adjacent links is obtained, and based on the correlation amount, a fixed frequency width set as a communication path, or Determining a variable frequency width and assigning it on the path.
- the allocation unit when allocating an optical wavelength as the fixed frequency width, refers to the path calculation result of the calculation result storage unit, and configures the light constituting the path of the path calculation result For each node, obtain the correlation amount of the wavelength usage state between the link to be added and the link adjacent via the optical node, and add the wavelength with the most continuous wavelength usage status between adjacent links You may comprise so that it may have a step.
- a frequency allocation device for selecting is provided.
- the frequency allocation device is A route / frequency calculation result storage means for storing a route / frequency result; Common free frequency that extracts the fiber groups that are connected to each other and generates logical information about the free frequency state common to the fibers by performing a logical operation on the logical information that represents each free frequency state of the extracted fiber group.
- the idle frequency state evaluation means Based on the generated idle frequency number information common to the fibers, the idle frequency state evaluation means for giving an evaluation value to the idle frequency state by adding the continuity of the idle frequency to the idle frequency state common between the fibers, A frequency / path determining unit that determines a frequency and a passing fiber set as a communication path based on the evaluation value calculated by the vacant frequency state evaluating unit, and stores the frequency and passing fiber in the path / frequency calculation result storage unit.
- FIG. 1 is a configuration diagram of an RWA network management device according to a first embodiment of the present invention.
- FIG. It is an example of the physical model of the network applied by embodiment of this invention.
- FIG. 5 shows the configuration of the RWA network management device used in the first embodiment.
- the network management apparatus 100 shown in the figure includes a routing unit 10, a wavelength assignment unit 20, a route calculation result storage unit 30, and a calculation result storage unit 40.
- the routing unit 10 uses the Shortest path algorithm (Fewest-hop, shortest distance, etc.) for route calculation, that is, routing, and the wavelength assigning unit 20 uses the least-fragmentation (LF) method for wavelength assignment.
- the Least-fragmentation (LF) method is a technique based on the present invention.
- the route calculation result storage unit 30 and the calculation result storage unit 40 are storage media such as a hard disk and a memory, the route calculation result storage unit 30 stores the route calculation result of the routing unit 10, and the calculation result storage unit 40 The middle and final calculation results of the wavelength allocation unit 20 are stored.
- FIG. 6 is a physical model of the network applied in the embodiment of the present invention.
- an optical path demand is generated from the node 1 to the node 6.
- the route calculation by the routing unit 10 consider a case where the route indicated by the thick dotted line as the addition target link in FIG.
- the Dijkstra method can be used for route calculation of the routing unit 10.
- FIG. 7 is a flowchart showing a processing procedure by the wavelength assigning unit 20 using the least-fragmentation method according to the first embodiment of the present invention.
- Step 101 The wavelength allocation unit 20 expresses the wavelength usage state of the link 1-2, which is the addition target link, as an array as shown in the example of S101 in FIG. To store.
- “1” is assigned to the used wavelength
- “0” is assigned to the unused wavelength.
- Step 102 Next, as seen from the link 1-2, the same array marking is performed for the links 1-a, 1-b, and 1-c adjacent via the node 1.
- the wavelength to be added is set to x1, but in the following calculation, “1” is inserted and calculated.
- Step 103 Next, as shown in the example shown in this step between each of these links, a product is obtained for each term in the array between link 1-2 and these adjacent links, and this is applied to all wavelengths. Addition is performed and the result is stored in the operation result storage unit 40.
- the “sum of products” in FIG. 7 is the result of this summation, and is represented by the total number of bits for which the result of the logical product value for each element in the array is true. For example, in the case of the product of link 1-2 and link 1-a, the first element in the array is 1 and 1, respectively, so the product is 1. The same product is obtained for the other links (links 1-b and 1-c), and this product is added over all wavelengths to obtain the sum, and the result is stored in the calculation result storage unit 40.
- Step 104 the calculation for obtaining this sum is similarly calculated for nodes on other routes, that is, nodes 2 to 6.
- node 2 since the addition target links are link 1-2 and link 2-3, links 1-2 and link adjacent to each other via node 2 (links 2-a, 2-b, 2-3) Find the product of each term in the array between and between link 2-3 and the link adjacent to node 2 via link 2 (links 2-a, 2-b, 1-2) This is summed over all wavelengths. Finally, the sum obtained for each node is added to all the nodes, and the value is stored in the calculation result storage unit 40.
- Step 105 Calculate all the wavelength candidates that can be operated as described above, and store the values in the calculation result storage unit 40.
- Step 106 The result obtained in Step 105 is read from the calculation result storage unit 40, and the wavelength candidate with the maximum total node sum is adopted as the additional wavelength. Note that this sum is an example of the correlation amount of the usage state of the wavelength or frequency between adjacent links. In addition, when the sum of all the nodes is maximized, it indicates that the continuity of the wavelength usage state is highest between adjacent links.
- FIG. 8 is a flowchart (part 1) of the operation of the extended least-fragmentation method according to the first embodiment of the present invention.
- step 105 The result obtained in step 105 is read from the calculation result storage unit 40, and if there are a plurality of total maximum wavelengths (step 201), the youngest wavelength is added on the path (step 202).
- FIG. 9 is a flowchart (part 2) of the operation of the extended least-fragmentation method according to the first embodiment of the present invention.
- step 301 When the result obtained in step 105 is read from the calculation result storage unit 40 and there are a plurality of maximum total wavelengths (step 301), the calculation is performed up to one hop ahead for the same total sum wavelength (step 302). A wavelength is added (step 303). That is, the adjacent link for which the sum of products is calculated is extended to an adjacent link via an optical node that is one hop ahead connected by an adjacent link via an optical node that constitutes a route.
- the young number is selected according to the First Fit method, but the old number may be selected, and the most used order according to the Most Used method, a random order, etc. are determined in advance. It may be selected according to any order. The same applies to the subsequent embodiments of the present application.
- a frequency allocation method for selecting a frequency width to be used on a path connecting the start point and the end point is provided.
- a calculation result storage means for storing a route and a frequency calculation result
- a router means for performing a route calculation and storing the route calculation result in the calculation result storage means
- an allocation for allocating a frequency width of the network refers to the path calculation result of the calculation result storage means, obtains the correlation amount of the wavelength or frequency usage state between adjacent links, and based on the correlation amount Then, a fixed frequency width or a variable frequency width to be set as a communication path is determined and assigned on the path.
- the allocation unit when allocating an optical wavelength as the fixed frequency width, the allocation unit refers to the path calculation result of the calculation result storage unit and performs the path calculation. For each optical node that makes up the resulting path, the amount of wavelength used is correlated between the link to be added and the link that is adjacent via the optical node. A wavelength assignment step of adding successive wavelengths.
- a link to be correlated is connected by an adjacent link via an optical node constituting the route. It may be extended to an adjacent link through an optical node.
- a young one of the optical wavelengths that are arbitrarily numbered is selected.
- the light wavelength of the light wavelength numbered in order from the shorter light wavelength or the longer light wavelength. You may make it select a thing.
- an array indicating a wavelength usage state is created for each link constituting the path on the storage means, and the optical node constituting the link and the path on the storage means
- a similar array is created for the adjacent links via, the amount of correlation between the link and the adjacent link is calculated, the calculation is performed for each optical node constituting the path, and the obtained correlation
- the wavelength with the largest amount is added. Note that the sum of correlation amounts is the total number of True bits of a new bit string obtained as a result of logical operation of logical bit strings representing wavelength or spectrum usage states. The same applies to other embodiments.
- a positive real number is used when the wavelength is used, and zero is used when the wavelength is not used, as an array indicating the use state of the wavelength.
- the wavelength allocation step when calculating the correlation amount for the adjacent link via the optical node, the product of the terms of the same wavelength in the array is calculated, and the sum total over all wavelengths of the product is used. It is said.
- FIG. 10 shows the configuration of the network management apparatus in the second embodiment of the present invention.
- a network management apparatus 200 shown in FIG. 10 adds a request acquisition unit 50 for acquiring an electrical path establishment request to the configuration of FIG. 5, and adds a wavelength allocation calculation unit 21, a determination unit 22, a mapping to the wavelength allocation unit 20.
- the configuration includes the portion 23.
- the operation of the wavelength assignment calculation unit 21 is the same as the operation of the wavelength assignment unit 20 in the first embodiment.
- routing unit 10 and the wavelength allocation calculation unit 21 of the present embodiment are the same as those of the first embodiment.
- the route calculation is performed by the routing unit 10, and the wavelength to be allocated is selected by the wavelength allocation unit 20.
- the determination unit 22 determines whether or not there is an existing wavelength, and the mapping unit 23 maps the electric path with priority over the already set wavelength based on the determination result. .
- the mapping unit 23 selects and maps the optimum wavelength by the LF method when there is a wavelength that has already been set, and maps by newly setting the optimum wavelength by the LF method when there is no wavelength that has already been set. .
- the LF (Least-Fragmentation) method is a method of evaluating a fragmentation situation on a path for a wavelength to be selected or newly established, and selecting or newly establishing a wavelength that causes no fragmentation.
- the evaluation method quantifies the correlation between adjacent links (example of evaluation function: sum of products, LEF, etc.).
- the frequency allocation method further includes a request reception step for receiving an electrical path establishment request, and when the path search is performed based on the electrical path establishment request in the wavelength allocation step,
- a mapping step for preferentially selecting a route with an existing wavelength and mapping the electrical path is included.
- an optical wavelength that maximizes the correlation amount is selected from the existing wavelengths. This correlation amount is obtained by extracting data of existing wavelength portions in the links constituting the path and adjacent links and performing logical operations on the respective existing wavelength portions.
- routing unit 10 and the wavelength allocation calculation unit 21 of the present embodiment are the same as those of the first embodiment.
- the wavelength allocation unit 20 determines the wavelength allocation.
- the mapping unit 23 adds the wavelength derived based on the first embodiment, and then adds the wavelength to the mapping unit 23. The electric path is mapped.
- the network management apparatus As shown in FIG. 12, the network management apparatus according to the present embodiment is connected to the photonic network 400, the wavelength use state management unit 24 that manages the wavelength use state of the photonic network 400, and the wavelength that stores the wavelength use state.
- the use state information storage unit 25 is provided in the wavelength allocation unit 20.
- routing unit 10 and the wavelength allocation calculation unit 21 of the present embodiment are the same as those of the first embodiment.
- the wavelength usage state management unit 24 determines the wavelength between the link to be added and the link adjacent to the optical node.
- the correlation of the use state is stored in the wavelength use state information storage unit 25, and the mapping unit 23 refers to the wavelength use state information storage unit 25 to consider the correlation of the use state of the wavelength, Add wavelengths that continue to be used.
- the procedure shown in the Least-fragmentation method of FIG. 7 in the previous embodiment is replaced with the procedure shown in FIG. 13 or FIG. 14, and the procedure shown in the extended Least-fragmentation method of FIG. Is replaced with the procedure shown in FIG.
- the sum of exclusive ORs in FIGS. 13 and 14 represents the total number of bits for which the result of the exclusive OR is True (1).
- the data of the additional wavelength portion extracted in FIG. 14 and the like is an element corresponding to the wavelength that is considered to be added in the array of the wavelength use state, and the exclusive OR of the additional wavelength portion is each This is an exclusive OR of an array composed only of elements corresponding to the wavelength being considered for addition in the wavelength wavelength utilization state array of the link.
- FIG. 13 is a flowchart when a method (exclusive OR) different from that in FIG. 7 in the fifth embodiment of the present invention is used. Only the processing parts different from those in FIG. 7 will be described below.
- the wavelength assigning unit 20 obtains an exclusive OR for the wavelength usage states of the adjacent links and the wavelength usage states of the links that are newly set as path setting candidates (step 103a). An addable wavelength candidate that minimizes the sum of all the calculated values (considered as integers) of the sum operation result and the sum of all calculation target links is selected as an additional wavelength (step 106a).
- FIG. 14 is a flowchart in the case of using a method (exclusive OR of additional wavelength portions) different from that in FIG. 7 in the fifth embodiment of the present invention. Only the processing parts different from those in FIG. 7 will be described below.
- the wavelength allocation unit 20 extracts the data of the additional wavelength portion of the link 1-2 and the links 1-a, 1-b, and 1-c, and adds the additional wavelength portion only to the additional wavelength portion.
- An exclusive OR is calculated (step 103b), and this process is omitted except for the added part.
- the wavelength with the smallest sum is selected and set as the additional wavelength (step 106b).
- FIG. 15 is a flowchart in the case where a method (a total minimum wavelength is plural) different from that in FIG. 8 in the fifth embodiment of the present invention is used.
- a young wavelength is added (step 202).
- a young wavelength is added (Step 202).
- an array indicating a wavelength usage state is created for each link constituting the path on the storage unit, and the link and the path are stored on the storage unit.
- a similar array is created for adjacent links via the optical nodes that constitute the optical node, and a correlation amount based on an exclusive OR between the link and the adjacent links is calculated, and the calculation is performed for the optical node that constitutes the path. It is performed for each, and the wavelength with the smallest total obtained correlation amount is added.
- an array indicating a wavelength use state is created for each link constituting the path on the storage unit, and the link and the path are configured on the storage unit. Create a similar array for adjacent links via the optical node, extract the additional wavelength part data between the link and the adjacent link, and calculate the correlation amount by exclusive OR of the additional wavelength part Then, the calculation is performed for each optical node constituting the path, and the wavelength with the smallest sum of the obtained correlation amounts is added.
- the light wavelength number that is arbitrarily numbered is selected.
- FIG. 16 is a flowchart when a method (logical sum of additional wavelength portions) different from that in FIG. 7 in the sixth embodiment of the present invention is used.
- the process shown in FIG. 16 is a method in which, in the method shown in FIG. 7, the wavelength allocation unit 20 calculates the logical sum of the additional wavelength portions only for the additional wavelengths. Specifically, the data of the additional wavelength portions of the link 1-2 and the link links 1-a, 1-b, and 1-c are extracted, the logical sum of the additional wavelength portions is calculated, and the sum is obtained (step 103c). .
- an array indicating the wavelength usage state is created on the storage unit for each link constituting the path, and the link and the path are stored on the storage unit.
- a similar array is created for the adjacent links via the optical nodes constituting the network, and the data of the additional wavelength portion between the link and the adjacent link is extracted, and the correlation amount by the logical sum of the additional wavelength portions is calculated. Then, the calculation is performed for each optical node constituting the path, and the wavelength at which the total of the obtained correlation amounts is the largest is added.
- a correlation regarding the usage state is obtained between the link constituting the determined path and another link to which the optical node connected to the link is connected.
- a wavelength allocation step is used in which a correlation amount of a wavelength usage state having a fixed frequency is obtained, and a wavelength having the most continuous wavelength usage state is added between adjacent links.
- the correlation of the frequency usage state between adjacent links is treated as a free common frequency state.
- the correlation amount an evaluation value given to the empty frequency state in consideration of the continuity of the empty frequency is used as the correlation amount.
- FIG. 18 shows the configuration of the frequency / path determining device according to the seventh embodiment of the present invention.
- the candidate route / frequency is determined for the path demand given by the frequency / route determining apparatus shown in FIG.
- a resource information DB 510 includes a resource information DB 510, a common free frequency information generation unit 520, a frequency state evaluation unit 530, a frequency / route determination unit 540, and a communication channel demand distribution DB 550.
- Each component has the following functions.
- Resource information DB 510 It is a DB that stores network topology information and resource information including free frequency information of fibers in the network.
- the topology information is information relating to the connectivity of the nodes of the communication network and the fibers existing between the nodes.
- Common free frequency information generation unit 520 A function of acquiring resource information of a plurality of fibers to be calculated from the resource information DB 510 and generating common free frequency information of the acquired fibers is provided.
- Frequency state evaluation unit 530 The common free frequency information generation unit 520 has an evaluation function for the free frequency information common to the fiber, and the continuity of the free frequency for the free resource information and the communication of the assumed communication path setting request by the designated evaluation method. An evaluation value is given in consideration of the distribution of the road (obtained from the communication path demand distribution DB 550).
- -Frequency / route determination unit 540 The candidate path between the start and end points of the communication path to be set is calculated, and the frequency as the allocation candidate is calculated. Based on the evaluation value given by the frequency state evaluation unit 530, each candidate path and the allocation frequency is calculated. For the combination, a function is provided that calculates a metric, which is a reference value for calculating a decision candidate from a plurality of candidates, based on the evaluation value, and calculates an optimum route / assignment frequency based on the calculated metric.
- the optimum route / assignment frequency means a route / assignment frequency having a maximum or minimum metric.
- Whether to select the route with the largest metric or the route with the smallest metric is set in advance in the frequency / route determination means as policy information. For example, when using the frequency state evaluation unit 530 in which the metric is proportional to the amount of resources such as necessary equipment, the candidate of the minimum metric is selected, and the amount of free resources, the degree of freedom of path / frequency selection, and the metric are When the proportional frequency state evaluation unit 530 is used, the candidate for the maximum metric is selected.
- -Channel demand distribution DB 550 Information about the bandwidth distribution of the arriving channel demand or the predicted value of the bandwidth distribution is stored.
- the frequency / path determination unit 540 calculates a plurality of path / frequency candidates from the start node to the end node, and adopts the obtained plurality of candidates by the following method. An evaluation value is given to the frequency state, and an optimum route / frequency is selected based on the evaluation value. An overview of the method of the present embodiment is shown in FIG.
- Step 401) Generating free frequency information common to frequency allocation fibers and related fibers:
- the common vacant frequency information generation unit 520 is configured to determine whether the adjacent fiber that can be directly reached from the fiber passing through the candidate path, or the fiber group including the adjacent fiber and the adjacent fiber from the adjacent fiber, The logical information about the free frequency information common between the two fibers is generated.
- Step 402 Calculate the evaluation value of the free frequency information in consideration of the band distribution of the arrival demand:
- the frequency state evaluation unit 530 gives an evaluation value to the logical information about the common fiber free frequency generated in step 401 using an evaluation function that takes into account the continuity of the free frequency and the bandwidth distribution of the arriving traffic.
- Step 403 Calculation of optimal candidates based on evaluation values:
- the frequency / route determination unit 540 performs the above evaluation on all route candidates / assigned frequency candidates, and selects a route / frequency having the best evaluation value as a candidate.
- the best evaluation value means that the evaluation value is maximized or minimized.
- the method of the present embodiment can also be applied to a band-fixed optical network that is considered as a special case of a band-variable optical network.
- the communication path represents an optical path set by using an optical fiber band by OFDM, WDM, or the like.
- resource information DB 510 topology information (node and fiber connection state) and fiber free spectrum information are generated and stored. This DB is updated each time the path accommodation status changes.
- Fiber free spectrum information is managed in fine-grained slots (or grids), and the usage status is represented by a logical value for each slot.
- the usage status is represented by a logical value for each slot.
- in use is represented by true (1) and unused is represented by false (0).
- topology information As topology information, topology information, fiber vacant frequency information, communication path start and end nodes, and frequency bandwidth are input from the resource information DB 510.
- the determination of candidate paths / frequency candidates of the required frequency width w from the start node s to the end node d in the input topology is performed according to the following procedure.
- Step 501 The common free frequency information generation unit 520 calculates all candidate routes from the start node s to the end node d, and sets the route group that is the set as K. This can be calculated by applying a commonly used Dijkstra algorithm, BFS method, k-shortest path method, or the like multiple times.
- a set of logical bit strings obtained by performing this for all the passing fibers of the path k is defined as P k .
- Step 504 The frequency / path determination unit 540 calculates all the frequency allocation patterns q (q has a width of w) that satisfy the required frequency width w and become allocation candidates for the path k to be calculated, Let Q k .
- Step 505 The frequency / route determination unit 540 assumes a case where one pattern of the frequency band Q k is assigned to the route k, and in the state after the assignment, the passing fiber h of the route k and h in the same manner as Step 503 above.
- the logical sum of the adjacent fiber g that can be directly reached from the logical sum is obtained, and the logical bit string obtained from the logical sum is defined as p ′ hqk .
- P ′ qk be a set of logical bit examples obtained by performing this for all the passing fibers on k.
- Step 506 The frequency state evaluation unit 530 gives an evaluation value by the evaluation function for P ′ qk and P obtained in Step 503, compares them, and sets a decrease in the evaluation value in the case of the path k and the frequency q as ⁇ qk .
- Step 507) Steps 504 to 506 are performed for all frequency assignment candidates q in Q k of path k.
- Step 508 The above steps 502 to 507 are performed for all route patterns k belonging to all route groups K.
- Step 509) The frequency / route determination unit 540 sets the combination of the route k and the frequency q, which has the smallest evaluation value decrease ⁇ qk , as the optimum route / frequency from s to d.
- FIG. 20 shows an example of a fiber pair (a pair of H component and G component) when calculating H, G, and P added in step 502 above.
- a 2-hop route is added from the start node s to the end node d.
- H ⁇ f25, f, 26, f27 ⁇
- combinations for generating a logical bit string p that is a component of P are as shown in the table of FIG.
- the calculation target fiber is G that can be directly reached from H.
- the fiber group G ′ that can be directly reached from G there is a common space among the three fibers H, G, and G ′.
- Frequency information can be acquired.
- each element of the logical bit set P to be evaluated or the logical bit p or p ′ hqk which is each element of P ′ qk is determined by an evaluation function (described later). Given an evaluation value for, and adding them together, an evaluation value for the set is obtained.
- a bit string (with a size B) is logically ORed between fibers and a new bit string is generated as common free frequency information.
- bit string representing the common free frequency information one or more continuous free frequency regions (generally dispersed and scattered in one or more of the fiber bands) are all extracted, and each free space is extracted.
- n be the number of consecutive consecutive empty slots.
- the evaluation value v (n) for the continuous empty area of the continuous area n formed by n continuous slots is given by an operation given by the following evaluation function.
- evaluation is performed with n ⁇ w i +1 for each assumed bandwidth, weighted by r i , and then added for all assumed bandwidth types.
- evaluation value addition for the channel demand that requires a frequency band larger than the continuous region n is excluded, and the calculation is performed to perform the evaluation suitable for the channel demand.
- bandwidth 1 slot (w 1 ), slot 2 (w 2 ), slot 3 (w 3 ), slot 4 (w 4 ) demand is 2 (r1): 1 (r2) : 1 (r3): 1 (r4) and appear.
- index i and w i of w i is equal example
- i and w i is may be equal.
- bit OR bit OR
- the evaluation value (9) for the three consecutive regions and the evaluation value (33) for the eight consecutive regions are added, and the evaluation value for the common free frequency region information of the fiber 1 and fiber 2 is calculated as 42.
- a path and a frequency connecting the start point and the end point of the optical signal are set.
- a frequency allocation device (frequency / path determining device) to be selected is provided.
- the frequency allocating device extracts a path / frequency calculation result storage means for storing a path / frequency result and a fiber group connected to each other, and performs a logical operation on logical information representing each free frequency state of the extracted fiber group.
- the vacant frequency state evaluation means for giving an evaluation value to the vacant frequency state in consideration of the continuity of the vacant frequency, and the frequency set as the communication path and the passage based on the evaluation value calculated by the vacant frequency state evaluation means
- Frequency / path determining means for determining a fiber and storing it in the path / frequency calculation result storage means.
- bandwidth distribution information of the channel demand is acquired from the channel demand distribution DB, and an evaluation value is determined in consideration of the demand band distribution of the assumed channel bandwidth.
- an evaluation value v (n) for a continuous empty area of a continuous area n formed by n consecutive slots is defined as follows.
- a, b, c, d, a ′, b ′, c ′, d ′, ⁇ , ⁇ ′, ⁇ are arbitrary constants, and can be set in the evaluation function unit in advance by the operator.
- the above evaluation function is applied to the evaluation function of the seventh embodiment, and the calculation is performed. Computation with the topology that is sometimes input is repeated by changing the evaluation function to minimize the required amount of equipment (blocking rate, number of accommodated communication channels, required amount of equipment, frequency utilization efficiency, etc.) Can be optimized for the assumed topology.
- the blocking rate means that the communication path setting cannot be set due to insufficient equipment amount or continuous wavelength restriction.
- the number of communication channels that can be accommodated represents the number of communication channels that can be accommodated in a certain amount of equipment.
- the required amount of equipment means the amount of required equipment such as the number of nodes, the number of node routes, the number of ports, and the number of fibers.
- the frequency utilization efficiency means the amount of frequency band in the fiber that is necessary when accommodating a certain communication path. The optimum value is determined by a policy (maximization / minimization, etc.) set by the operator.
- Step 601) The bandwidth distribution of the assumed topology and the assumed communication channel demand is determined.
- Step 602 a coefficient pattern for each of a, b, c, d, a ', b', c ', d', ⁇ , ⁇ ', ⁇ is generated.
- Step 603 Select one of the generated coefficient patterns, define an evaluation function with the corresponding coefficient, accommodate the communication path with the assumed topology and the assumed demand, and save the result.
- Step 604 Step 603 is repeated by changing the pattern generated in Step 602.
- Step 605) The results determined by repeating Steps 603 and 604 are compared, and an evaluation function is defined with a coefficient that gives the optimum result.
- Step 605 as an evaluation standard for giving an optimum result, a blocking rate, the number of accommodated communication paths, a necessary facility amount, a frequency utilization efficiency, and a combination thereof can be used.
- the blocking rate means that the communication path setting cannot be set due to insufficient equipment amount or continuous wavelength restriction.
- the number of communication channels that can be accommodated represents the number of communication channels that can be accommodated in a certain amount of equipment.
- the required amount of equipment means the amount of required equipment such as the number of nodes, the number of node routes, the number of ports, and the number of fibers.
- the frequency utilization efficiency means the amount of frequency band in the fiber that is necessary when accommodating a certain communication path.
- the optimum value is determined by a policy (maximization / minimization, etc.) set by the operator.
- step 604 when the next coefficient pattern is selected, the result obtained in step 603 is taken into consideration, and the coefficient pattern (a, b,, c, d, a ', b ', c', d ', ⁇ , ⁇ ', ⁇ ) can be selected to make the coefficient optimization more efficient.
- the optimization efficiency is the number of iterations required to obtain an optimal evaluation function and the required calculation time.
- the continuous free slot area larger than the expected maximum bandwidth of the communication path does not need to take into account the accommodation pattern of the maximum bandwidth or more because all the continuous slot areas are not used in one communication path.
- the evaluation function (referred to as v1 (n)) for the continuous free slot area larger than the maximum bandwidth is related to the number of consecutive slots n than the evaluation function (referred to as v2 (n)) for the continuous area smaller than the maximum bandwidth. If the function order is reduced, an optimal evaluation function can be determined efficiently. For example, when v2 (n) is an order for a quadratic function, v1 (n) may be defined by a linear function with a lower order. Here, the increase speed of the absolute value of the function with respect to the order and n is represented.
- the present embodiment may be implemented by logarithmizing the evaluation value as necessary.
- the frequency state evaluation unit assuming the topology of the communication network for setting the communication path and the communication path bandwidth distribution, changing the evaluation function for calculating the evaluation value,
- the frequency function evaluation step is performed one or more times, and an evaluation function that obtains better results is adopted.
- FIG. 23 shows a configuration of a frequency / path determining device when a fiber weighting DB is provided in the ninth embodiment of the present invention.
- the configuration of FIG. 18 includes a link weight DB 560 that is a database for storing the weight value for each fiber, and when the common free frequency information is evaluated, the link weight DB 560 is included. It is also possible to evaluate by taking into account the weight given to each fiber to be evaluated. As a result, it is possible to save the resources of the specific fiber for maintenance / management reasons and to use the resources suitable for actual operation.
- the link weight DB stores a weight value for each link for each fiber.
- the frequency state evaluation unit 530 multiplies the evaluation function for evaluating v (n) described in the seventh embodiment by the weight values of both of the fibers constituting the pair,
- the eighth embodiment is implemented.
- x c is the weight of the fiber on the candidate path
- x a is the weight of the adjacent fiber that forms a pair with the fiber on the candidate path.
- Step 701 The bandwidth distribution of the assumed topology and the assumed communication channel demand is determined.
- Step 702 Next, a plurality of weight coefficient patterns are generated.
- Step 703 The frequency / route determination unit 540 in the seventh embodiment accommodates the path for the assumed demand in the assumed topology and saves the result.
- Step 703 Step 703 is repeated for the number of patterns by changing the pattern generated in step 702.
- Step 705 The results determined by repeating Steps 703 and 704 are compared, and an evaluation function is defined with a coefficient that gives the optimum result.
- weights for each fiber and each fiber pair can be taken into account, and the weights can be specified in detail.
- the frequency state evaluation means refers to the weight DB for storing the weight information for each fiber or each fiber pair, and the weight for each fiber or fiber pair to be evaluated. An evaluation value is given in consideration of the value.
- each functional unit such as the routing unit and the wavelength allocation unit of the network management device
- the operation of each functional unit is constructed as a program, and is installed and executed on a computer used as the network management device. It is possible to circulate through. The same applies to the frequency / route determination device.
- the constructed program can be stored in a portable storage medium such as a hard disk, a flexible disk, or a CD-ROM, and installed in a computer or distributed.
- a portable storage medium such as a hard disk, a flexible disk, or a CD-ROM
- the wavelength (frequency) in each link ) Is used to effectively suppress the generation of fragmentation in a transparent optical path network and optimize the utilization efficiency of wavelength (frequency) resources by determining the wavelength or frequency to be newly allocated. be able to. Therefore, according to the embodiment of the present invention, for example, as shown in FIG. 17, it is possible to arrange wavelengths so as to prevent wavelength fragmentation. Further, the same effect can be obtained even when the wavelength width is different for each path.
- the present application includes Japanese Patent Application No. 2010-238862 filed on October 25, 2010, Japanese Patent Application No. 2011-64759 filed on March 23, 2011, and Japanese Application filed on July 14, 2011.
- the priority based on national patent application 2011-156119 is claimed, and the entire contents of 2010-238862, 2011-64759, and 2011-156119 are incorporated in this application.
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Abstract
Description
経路、及び周波数の計算結果を格納する計算結果記憶手段、経路計算を行い、経路計算結果を該計算結果記憶手段に格納するルータ手段と、前記ネットワークの周波数幅を割り当てる割当手段と、を有する装置において、
前記割当手段が、
前記計算結果記憶手段の経路計算結果を参照して、隣接リンク間での波長または周波数の使用状態の相関量を求め、該相関量に基づいて、通信路として設定する、固定の周波数幅、または、可変の周波数幅を決定し、前記経路上に割り当てるステップを有する。
経路・周波数結果を格納する経路・周波数計算結果記憶手段と、
互いに接続されるファイバグループを抽出し、抽出したファイバグループのそれぞれの空き周波数状態を表す論理情報について、論理演算することで、ファイバ間共通の空き周波数状態についての論理情報を生成する、共通空き周波数情報生成手段と、
生成したファイバ間共通の空き周波数数情報を基に、ファイバ間共通の空き周波数状態に対して、空き周波数の連続性を加味して空き周波数状態に評価値を与える空き周波数状態評価手段と、
前記空き周波数状態評価手段で算出した前記評価値を基準として、通信路として設定する周波数と通過ファイバを決定し、前記経路・周波数計算結果記憶手段に格納する周波数・経路決定手段と、を備える。
本発明の第1の実施の形態を図5~9を用いて説明する。
図10は、本発明の第2の実施の形態におけるネットワーク管理装置の構成を示す。
本実施の形態におけるネットワーク管理装置の構成は、前述の第2の実施の形態における図10に順ずる。
本実施の形態におけるネットワーク管理装置は、図12に示すように、フォトニックネットワーク400に接続され、フォトニックネットワーク400の波長使用状態を管理する波長使用状態管理部24、波長使用状態を格納する波長使用状態情報記憶部25を波長割当部20に設けたものである。
本実施の形態では、前述の実施の形態において、図7のLeast-fragmentation法に示した手順を図13または図14に示す手順に置き換え、また、図8の拡張Least-fragmentation法に示した手順を図15に示す手順に置き換えて実施するものである。図13、図14の排他的論理和の和とは、排他的論理和の結果がTrue(1)となったビット総数を表す。また、図14等で抽出する追加波長部分のデータとは、波長利用状態の配列の内で追加を検討している波長に該当する要素であり、追加波長部分の排他的論理和とは、各リンクの波長利用状態の配列の内で追加を検討している波長に該当する要素のみから構成された配列の排他的論理和である。
前述の第1の実施の形態、及び、第2~4の実施の形態における、第1の実施の形態と同等の手順において、図7に示すLeast-fragmentation法を図16に示す方法で置き換えて実施することができる。
本願の第1~第6の実施の形態は、主に固定の周波数幅を割り当てる周波数・経路決定方法を用いる装置に関する形態を説明した。本実施の形態以降では、主に可変幅の周波数を割り当てる周波数・経路決定方法を用いる装置に関する形態を説明する。
網のトポロジ情報、および網内のファイバの空き周波数情報からなるリソース情報、を記憶するDBである。ここで、トポロジ情報とは、通信網のノードの接続性と、ノード間毎に存在するファイバに関する情報である。
計算対象とする複数ファイバのリソース情報をリソース情報DB510から取得し、取得したファイバの共通の空き周波数情報を生成する機能を備える。
共通空き周波数情報生成部520が生成したファイバ共通の空き周波数情報についての評価機能を備え、指定された評価方法によって、空きリソース情報について空き周波数の連続性、及び想定される通信路設定要求の通信路の分布(通信路需要分布DB550から取得)を加味して評価値を与える。
設定を試みる通信路の始点・及び終点間の候補経路、及び割り当て候補となる周波数を算出し、周波数状態評価部530の与えられた評価値に基づき、候補となっている各経路及び割り当て周波数の組み合わせについて、複数候補から決定候補を算出するための基準となる数値であるメトリックを評価値に基づきを算出し、算出したメトリックに基づいて、最適な経路・割り当て周波数を算出する機能を備える。ここで、最適な経路・割り当て周波数とはメトリックが最大もしくは最小な経路・割り当て周波数を意味する。メトリックが最大な経路を選択するか、もしくはメトリックが最小な経路を選択するかはあらかじめポリシー情報として、周波数・経路決定手段に設定されている。例えば、必要な設備等のリソース量とメトリックが比例する周波数状態評価部530を利用している場合は、最小メトリックの候補を選択し、空きリソース量や、経路・周波数選択の自由度とメトリックが比例する周波数状態評価部530を利用している場合は、最大のメトリックの候補を選択する。
到着する通信路需要の帯域分布もしくはその帯域分布の予測値についての情報が保存される。
共通空き周波数情報生成部520は、候補経路を通過するファイバから直接到達可能な隣接ファイバ、またはそれら隣接ファイバとさらにそこから隣接されるファイバを含めたファイバグループについて、通過経路上のそれぞれのファイバとのファイバ間共通の空き周波数情報についての論理情報を生成する。
周波数状態評価部530は、ステップ401で生成されたファイバ共通空き周波数についての論理情報について、空き周波数の連続性、また到着するトラフィックの帯域分布を加味した評価関数にて、評価値を与える。
周波数・経路決定部540は、上記の評価を全ての経路候補・割り当て周波数候補について実施し、評価値が最善の経路・周波数を候補として選択する。ここで評価値が最善とは、評価値が最大もしくは最小となることを意味する。
ステップ503)共通空き周波数情報生成部520は、経路kの通過ファイバであるH(構成要素h=1,…, h=m)について、直接到達可能な隣接ファイバ群GlをリソースDB510のトポロジ情報より抽出し、Gl構成要素gl(gl=1,…,L)それぞれに対して、hとgの互いのファイバ周波数利用状況(候補パスを収容していない状態)の論理情報について論理和を取得し、論理和を取得した論理ビット列をphgとする。これを共通空き周波数情報とする。また、これを経路kの全ての通過ファイバについて実施して求めた、論理ビット列の集合をPkとする。なお経路kの通過ファイバ全てについて実施する際、経路kについての計算課程で、一度あるファイバについての隣接ファイバとして演算されたファイバは、それ以降隣接ファイバに重複して追加をすることを避ける。
なお、ステップ503において、演算対象のファイバはHから直接到達可能なGとしているが、Gからさらに直接到達可能なファイバ群G'を加味し、H、G、G'の3ファイバ間で共通空き周波数情報を取得することができる。同様にさらに隣接ファイバを考えることで4ファイバ以上とすることができる。このように、共通空き周波数情報を取得する範囲を拡大することで、より効果的な周波数リソースの評価が可能となり、さらに効率的に周波数リソースを活用することができるようになる。
ファイバ1 : 11111000000101000101110000000000
ファイバ2 : 10101111000010111010101000000001
また、需要の帯域分布は、帯域幅1スロット(w1)、2スロット(w2)、3スロット(w3)、4スロット(w4)の需要がそれぞれ2(r1):1(r2):1(r3):1(r4)で、現れるものとする。
ファイバ1、ファイバ2のビット列の論理和(bit OR)を取得すると、
11111111000111111111111000000001
となる。
1)帯域幅1スロットに対して(i=1)
帯域幅が連続領域n以下であるため
f(3,1)・r1=(3-1+1)・2=6
2)帯域幅2スロットに対して(i=2)
帯域幅が連続領域n以下であるため
f(3,2)・r2=(3-2+1)・1=2
3)帯域幅3スロットに対して(i=3)
帯域幅が連続領域n以下であるため
f(3,3)・r3=(3-3+1)・1=1
4)帯域幅4スロットに対して(i=4)
帯域幅が連続領域nより大きいため
f(3,4)・r4=0・1=0
1)~4)までの値を足し、3連続の領域に対する評価値は9となる。
1)帯域幅1スロットに対して(i=1)
帯域幅が連続領域n以下であるため
f(3,1)・r1=(8-1+1)・2=16
2)帯域幅2スロットに対して(i=2)
帯域幅が連続領域n以下であるため
f(3,2)・r2=(8-2+1)・1=7
3)帯域幅3スロットに対して(i=3)
帯域幅が連続領域n以下であるため
f(3,3)・r3=(8-3+1)・1=6
4)帯域幅4スロットに対して(i=4)
帯域幅が連続領域n以下であるため
f(3,4)・r4=(8-4+1)・1=5
1)~4)までの値を足し、8連続の領域に対する評価値は33となる。
前記周波数状態評価手段において、通信路需要分布DBから通信路需要の帯域分布情報を取得し、想定される通信路帯域の需要帯域分布を加味して、評価値を決定する。
第7の実施の形態にて、使用した評価関数について、以下に述べるような演算を適用することも可能である。
図23は、本発明の第9の実施の形態におけるファイバごとの重み付けDBを備えた場合の周波数・経路決定装置の構成を示す。
上記のように本発明の実施の形態によれば、いろいろな経路の光パス需要があった場合に、その需要に応えるために経路及び波長(周波数)を割り当てる際に、各リンクにおける波長(周波数)の利用状況を考慮することで、新たに割り当てる波長または周波数を決定することにより、トランスペアレント型光パス網におけるFragmentationの発生を効果的に抑制し、波長(周波数)リソースの利用効率を最適化することができる。そのため、本発明の実施の形態によれば、例えば図17に示したように、波長の断片化を防ぐよう波長を配置することが可能となる。さらに、パスごとに波長の幅が異なる場合であっても同様の効果を得ることができる。
20 波長割当部
21 波長割当演算部
22 判定部
23 マッピング部
24 波長状態管理部
25 波長使用状況情報記憶部
100,200,300 ネットワーク管理装置
400 フォトニックネットワーク
510 リソース情報DB
520 共通空き周波数情報生成部
530 周波数状態評価部
540 周波数・経路決定部
550 通信路需要分布DB
560 リンク重み付けDB
Claims (22)
- 光信号を電気的に終端することなくスイッチングする光スイッチを含む光ノードにより構成されるフォトニックネットワークにおいて、光信号の始点と終点が与えられると、該始点と終点を結ぶ経路上において用いる周波数幅を選択する周波数割当方法であって、
経路、及び周波数の計算結果を格納する計算結果記憶手段、経路計算を行い、経路計算結果を該計算結果記憶手段に格納するルータ手段と、前記ネットワークの周波数幅を割り当てる割当手段と、を有する装置において、
前記割当手段が、
前記計算結果記憶手段の経路計算結果を参照して、隣接リンク間での波長または周波数の使用状態の相関量を求め、該相関量に基づいて、通信路として設定する、固定の周波数幅、または、可変の周波数幅を決定し、前記経路上に割り当てる
ことを特徴とする周波数割当方法。 - 前記固定の周波数幅としての光波長を割り当てる際に、
前記割当手段が、前記計算結果記憶手段の前記経路計算結果を参照して、該経路計算結果の経路を構成する光ノード毎に、追加しようとするリンクと当該光ノードを介して隣接するリンクの間で波長の使用状態の相関量を求め、隣接リンク間で最も波長の使用状態が連続する波長を追加する波長割当ステップを有する
請求項1記載の周波数割当方法。 - 前記波長割当ステップにおいて、
前記相関量が等しい2つ以上の波長が存在した場合に、相関の対象となるリンクを、当該経路を構成する光ノードを介して隣接するリンクで結ばれる1ホップ先の光ノードを介して隣接するリンクまで拡張する
請求項2記載の周波数割当方法。 - 前記波長割当ステップにおいて、
前記相関量が等しい2つ以上の波長が存在した場合に、任意に番号付けした光波長のうち、若番のものを選択する
請求項2又は3に記載の周波数割当方法。 - 前記波長割当ステップにおいて、
前記相関量が等しい2つ以上の波長が存在した場合に、光波長が短い方、または、光波長が長い方から順に番号付けした光波長のうち、若番のものを選択する
請求項2乃至4のうちいずれか1項に記載の周波数割当方法。 - 前記波長割当ステップにおいて、
記憶手段上に、前記経路を構成するリンク毎に、波長の使用状態を示す配列を作成し、
前記記憶手段上に、前記リンクと前記経路を構成する光ノードを介して隣接するリンクについても同様の配列を作成し、
前記リンク及び隣接するリンクとの間の相関量を演算し、該演算を当該経路を構成する光ノードそれぞれについて演算し、
得られた相関量の合計が最も大きくなる波長を追加する
請求項2乃至5のうちいずれか1項に記載の周波数割当方法。 - 前記波長割当ステップにおいて、
記憶手段上に、前記経路を構成するリンク毎に、波長の使用状態を示す配列を作成し、
前記記憶手段上に、前記リンクと前記経路を構成する光ノードを介して隣接するリンクについても同様の配列を作成し、
前記リンク及び隣接するリンクとの間の排他的論理和による相関量を演算し、該演算を当該経路を構成する光ノードそれぞれについて行い、
得られた相関量の合計が最も小さくなる波長を追加する
請求項2乃至5のうちいずれか1項に記載の周波数割当方法。 - 前記波長割当ステップにおいて、
記憶手段上に、前記経路を構成するリンク毎に、波長の使用状態を示す配列を作成し、
前記記憶手段上に、前記リンクと前記経路を構成する光ノードを介して隣接するリンクについても同様の配列を作成し、
前記リンク及び隣接するリンクとの間の追加波長部分のデータを抽出し、追加波長部分の排他的論理和による相関量を演算し、該演算を当該経路を構成する光ノードそれぞれについて行い、
得られた相関量の合計が最も小さくなる波長を追加する
請求項2乃至5のうちいずれか1項に記載の周波数割当方法。 - 前記波長割当ステップにおいて、
記憶手段上に、前記経路を構成するリンク毎に、波長の使用状態を示す配列を作成し、
前記記憶手段上に、前記リンクと前記経路を構成する光ノードを介して隣接するリンクについても同様の配列を作成し、
前記リンク及び隣接するリンクとの間の追加波長部分のデータを抽出し、追加波長部分の論理和による相関量を演算し、該演算を当該経路を構成する光ノードそれぞれについて行い、
得られた相関量の合計が最も大きくなる波長を追加する
請求項2乃至5のいずれか1項に記載の周波数割当方法。 - 前記波長割当ステップにおいて、
前記相関量の合計が最も小さくなる波長が2つ以上存在した場合に、任意に番号付けした光波長のうち、若番のものを選択する
請求項7又は8に記載の周波数割当方法。 - 前記波長割当ステップにおいて、
前記波長の使用状態を示す配列として、
前記波長の使用時に正の実数を用い、未使用時に零を用いる
請求項6乃至9のうちいずれか1項に記載の周波数割当方法。 - 前記波長割当ステップにおいて、
前記光ノードを介して隣接するリンクについて相関量を演算する際に、前記配列の同じ波長の項の積を演算し、当該積の全ての波長にわたる総和を用いる
請求項6乃至9のうちいずれか1項に記載の周波数割当方法。 - 電気パスの開設要求を受け付ける要求受付ステップを更に有し、
前記波長割当ステップにおいて、
前記電気パスの開設要求に基づき経路探索した場合に、既存波長がある場合は、既存波長のある経路を優先的に選択し、当該電気パスをマッピングするマッピングステップを含み、
前記マッピングステップにおいて、
前記既存波長がある場合に、該既存波長のうち、前記相関量が最大となる光波長を選択する
請求項2乃至10のうちいずれか1項に記載の周波数割当方法。 - 電気パスの開設要求を受け付ける要求受付ステップを更に有し、
前記波長割当ステップにおいて、
前記電気パスの開設要求に基づき経路探索した場合に、既存波長が存在しない場合、前記相関量が最大となる光波長を新設し、当該電気パスをマッピングする
請求項2乃至10のいずれか1項に記載の周波数割当方法。 - 前記波長割当ステップにおいて、
前記経路計算結果の経路を構成する光ノード毎に、追加しようとするリンクと当該光ノードを介して隣接するリンクの間で波長の使用状態の相関量に基づいて、隣接リンク間で最も波長の使用状態が連続する波長を追加する
請求項1記載の周波数割当方法。 - 前記可変の周波数幅としての周波数を割り当てる際に、
前記割当手段が、
互いに接続されるファイバグループを抽出し、抽出したファイバグループのそれぞれの空き周波数状態を表す論理情報について、論理演算することで、ファイバ間共通の空き周波数情報についての論理情報を生成する共通空き周波数情報生成ステップと、
前記共通空き周波数情報生成ステップで生成されたファイバ間共通の空き周波数数情報を基に、ファイバ間共通の空き周波数状態に対して、空き周波数の連続性を加味して空き周波数状態に評価値を与える周波数状態評価ステップと、
前記周波数状態評価ステップで算出された評価値を基準として、通信路として設定する周波数と通過ファイバを決定し、経路・周波数計算結果記憶手段に格納する周波数割当ステップと、
を有する請求項1記載の周波数割当方法。 - 前記周波数状態評価ステップにおいて、
通信路需要分布DBから通信路需要の帯域分布情報を取得し、想定される通信路帯域の需要帯域分布を加味して、評価値を決定する
請求項16記載の周波数割当方法。 - 前記周波数状態評価ステップにおいて、
通信路を設定する通信網のトポロジと通信路帯域分布を想定し、前記評価値を算出する評価関数を変更して、前記周波数状態評価ステップを一回以上実施し、より良い結果の得られる評価関数を採用する
請求項16記載の周波数割当方法。 - 前記周波数状態評価ステップにおいて、
ファイバ毎もしくはファイバペア毎の重み付け情報を保存する重み付けDBを参照して、評価対象となっているファイバまたはファイバペア毎の重み値を加味して評価値を与える
請求項16記載の周波数割当方法。 - 光信号を電気的に終端することなくスイッチングする光スイッチを含む光ノードにより構成されるフォトニックネットワークにおいて、光信号の始点と終点を結ぶ経路及び周波数を選択する周波数割当装置であって、
経路・周波数結果を格納する経路・周波数計算結果記憶手段と、
互いに接続されるファイバグループを抽出し、抽出したファイバグループのそれぞれの空き周波数状態を表す論理情報について、論理演算することで、ファイバ間共通の空き周波数状態についての論理情報を生成する、共通空き周波数情報生成手段と、
生成したファイバ間共通の空き周波数数情報を基に、ファイバ間共通の空き周波数状態に対して、空き周波数の連続性を加味して空き周波数状態に評価値を与える空き周波数状態評価手段と、
前記空き周波数状態評価手段で算出した前記評価値を基準として、通信路として設定する周波数と通過ファイバを決定し、前記経路・周波数計算結果記憶手段に格納する周波数・経路決定手段と、
を備えたことを特徴とする周波割当装置。 - 想定される通信路需要の帯域分布を記憶する通信路需要分布DBを更に有し、
前記共通空き周波数情報生成手段は
前記通信路需要分布DBから通信路需要の帯域分布情報を取得し、想定される通信路帯域の帯域分布を加味して、評価値を決定する手段を含む
請求項20記載の周波割当装置。 - ファイバ毎もしくはファイバペア毎の重み付け情報を保存する重み付けDBを更に備え、
前記周波数状態評価手段は、
ファイバ間共通の空き周波数状態に対して評価値を与える際に、前記重み付けDBに保存されたファイバ毎もしくはファイバペア毎の重み付け情報を取得し、評価対象となっているファイバ毎もしくはファイバペア毎の重み値を加味して評価値を与える手段を含む
請求項20記載の周波割当装置。
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