JP2014155017A - Optical network controller and program - Google Patents

Abstract

A control apparatus that performs effective defragmentation in an optical network capable of setting wavelength paths of different bandwidths.
An optical network control device capable of setting wavelength paths of different bandwidths by using a basic bandwidth as a slot and using one slot or a plurality of consecutive slots in order of wavelengths is provided with a slot usage order. The wavelength path is moved to an unused slot that is adjacent to the wavelength path and has a higher use order than the wavelength path, and the wavelength path to be moved uses a plurality of slots. In some cases, it is determined based on the quality information whether the number of used slots of the wavelength path can be reduced by changing the modulation format of the wavelength path in the moved slot, and the number of used slots of the wavelength path is determined. If it can be reduced, the state after the defragmentation process is determined by reducing.
[Selection] Figure 2

Description

  The present invention relates to an optical network control technique.

  In an optical network, wavelength paths to be set are not changed, and wavelength paths that are no longer necessary are deleted or new wavelength paths are newly set to sections that are needed according to traffic demand or the like. Here, when the setting and deletion of the wavelength path are repeated, the free wavelength and the fragmentation (fragmentation) occur. For this reason, Non-Patent Documents 1 and 2 propose a method for defragmentation (defragmentation). In the methods described in Non-Patent Documents 1 and 2, basically, when the wavelength path is deleted after setting the wavelength to be used, a wavelength whose use rank is one lower than that of the deleted wavelength path. It is determined whether or not the path can be moved to the wavelength of the deleted wavelength path. If the path can be moved, the path is moved. Whether the wavelength path can be moved to the wavelength of the moved wavelength path by moving the wavelength by one less than the used order of the moved wavelength path, as in the case of deleting the wavelength path. If it is possible to move, it is moved.

  Specifically, it is assumed that the wavelength path is set as shown in FIG. 4A and 4B, a slot is an index indicating a band in which one wavelength path of a predetermined band can be set, and that slot numbers are adjacent means that wavelengths are adjacent. Means. In this example, the lower the slot number, the higher the order of use. In the example of FIG. 4A, two wavelength paths # 1 and # 2 are set using the wavelength corresponding to the slot # 1. Note that the wavelength path # 1 is set between the node device # 1 and the node device # 2, and the wavelength path # 2 passes between the node device # 3 and the node device # 5 via the node device # 4. Is set to Similarly, two wavelength paths # 3 and # 4 are set using the wavelength corresponding to slot # 2, and two wavelength paths # 5 and # 6 are set using the wavelength corresponding to slot # 3. The two wavelength paths # 7 and # 8 are set using the wavelength corresponding to the slot # 4. In the state shown in FIG. 4A, the slot # 1 has an empty space between the node device # 2 and the node device # 3, and the slot # 3 has the node device # 3 and the node device #. There is a vacancy in the section between 4 and slot # 4, and there is a vacancy in the section between node apparatus # 2 and node apparatus # 3.

  In the state shown in FIG. 4A, it is assumed that wavelength path # 2 has been deleted. In that case, it is possible to move the wavelength path # 4 to the slot # 1 among the wavelength paths using the slot # 2 that is lower in the order of use than the slot # 1 used by the wavelength path # 2. It becomes. Therefore, in the methods described in Non-Patent Documents 1 and 2, the wavelength path # 4 is moved to the slot # 1. Furthermore, in the methods described in Non-Patent Documents 1 and 2, the wavelength path # 6 is moved to the slot # 2 which is vacant by moving the wavelength path # 4 to the slot # 1, and the wavelength path # 6 is changed to the slot. The wavelength path # 8 is moved to the slot # 3 which becomes empty by moving to # 2. Accordingly, the setting state of the wavelength path is as shown in FIG. 4B by defragmentation triggered by the deletion of the wavelength path # 2.

  The methods described in Non-Patent Documents 1 and 2 are a method called push-pull, and in order to change the wavelength of the wavelength path, the cross-connect bandwidth in the intermediate node is moved before and after the movement. Change the wavelength to include the later wavelength, and then gradually change the wavelength (frequency) of the light-emitting element to the wavelength after the movement at the start point of the wavelength path. After changing the wavelength, the bandwidth of the cross-connect at the intermediate node Is changed to the wavelength after movement. Specifically, in moving the wavelength path # 4 to the slot # 1 in FIG. 4A, first, in the node devices # 3 and # 4 which are intermediate nodes, the bandwidth of the cross-connect is changed to the slot # 1 and Change to include both wavelengths of # 2, and then change the wavelength of the light emitting elements in node devices # 2 and # 5 from the wavelength corresponding to slot # 2 to the wavelength corresponding to slot # 1, and change the wavelength Thereafter, the cross-connect bandwidth in the node devices # 3 and # 4 is changed to include only the slot # 1.

F. Cugini, et al. , "Push-pull technology for fragration in flexible optical networks," OFC / NFOEC 2012, 2012 X. Wang, et al. , "A hitless defragmentation method for self-optimizing flexible grid optical networks," ECOC 2012, 2012

  Currently, elastic optical networks having various bandwidths and setting wavelength paths using various modulation formats have been proposed. However, the methods described in Non-Patent Documents 1 and 2 are for an optical network in which the bandwidth of each wavelength path is the same fixed value, and effective defragmentation is required in an elastic optical network.

  The present invention provides a control device and a program for executing effective defragmentation in an optical network capable of setting wavelength paths with different bandwidths.

  According to an aspect of the present invention, there is provided an optical network control device capable of setting wavelength paths of different bandwidths using a basic bandwidth as a slot and using one slot or a plurality of slots that are consecutive in wavelength order, Holding means for holding information for calculating wavelength path quality information, determination means for determining a state after defragmentation processing for preventing fragmentation of unused slots, and a control command for controlling the optical network Control means for causing the determination means to determine the state after the defragmentation processing when a predetermined condition is transmitted to the optical network, and the determination means determines the slot usage order. If the wavelength path can be moved to an unused slot that is adjacent to the wavelength path and has a higher use order than the wavelength path, In addition, when the wavelength path to be moved is one that uses a plurality of slots, the modulation format of the wavelength path may be changed in the slot after movement to reduce the number of used slots of the wavelength path. If the number of used slots of the wavelength path can be reduced by determining whether it is possible based on the quality information calculated from the information held by the holding unit, the state after the defragmentation process can be reduced. It is characterized by determining.

  Effective defragmentation can be performed in an optical network in which wavelength paths of different bandwidths can be set.

1 is an exemplary system configuration diagram according to one embodiment. FIG. Explanatory drawing of the defragmentation by one Embodiment. The example block diagram of the control apparatus by one Embodiment. Explanatory drawing of defragmentation by push pull.

  Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In the following drawings, components that are not necessary for the description of the embodiments are omitted from the drawings.

  FIG. 1 is an exemplary system configuration diagram according to the present embodiment. The optical network 10 includes a plurality of node devices 1, and the control device 2 sets a wavelength path between the two node devices 1 of the optical network 10. The optical network 10 is a so-called elastic optical network, and can set wavelength paths of various modulation formats in various bands. Note that the bandwidth occupied by the wavelength path is represented by an integral multiple of the fundamental bandwidth, and the fundamental bandwidth is expressed as a slot. Then, like the expression used in FIG. 4, the slots are numbered in the order of their center wavelengths. Therefore, the optical network 10 is a network capable of setting a wavelength path that occupies one or a plurality of consecutive slots in the wavelength order.

  FIG. 2A shows a state where a total of six wavelength paths are set in the five node devices # 1 to # 5. Each node device has an optical link with a node device having a different number. Each optical link is divided into four bands, and slots # 1 to # 4 are arranged in order of frequency. In this example, the lower the slot number is, the higher the usage order is, but the reverse is also possible. Furthermore, the usage slot of the central slot is made the highest, and the usage slot is lowered as it goes from the center to the end, so that the usage slots can be collected in the center. Furthermore, by increasing the usage order of the slots at both ends and lowering the usage order of the central slot, it is possible to collect the used slots at both ends. That is, any method can be used for assigning the usage order. In FIG. 2A, the wavelength path # 1 is a band that occupies one slot, and is set between the node device # 1 and the node device # 2. The wavelength path # 2 is a band that occupies one slot, and is set between the node device # 3 and the node device # 5. Further, the wavelength path # 3 is a band that occupies two slots, and is set between the node device # 1 and the node device # 2. Further, the wavelength path # 4 is a band that occupies two slots, and is set between the node device # 2 and the node device # 4. Further, the wavelength path # 5 is a band that occupies one slot, and is set between the node device # 1 and the node device # 3. Further, the wavelength path # 6 is a band that occupies one slot, and is set between the node device # 3 and the node device # 5. In FIGS. 2A to 2C, a blank column is an empty band.

  Assume that wavelength path # 2 has been deleted in this state. In this case, when the defragmentation described in Non-Patent Documents 1 and 2 is executed, the result is as shown in FIG. On the other hand, in the present embodiment, when moving a wavelength path that occupies a band of 2 slots or more, the wavelength after the movement is occupied by changing the modulation format to a multi-valued one. It is determined whether or not the bandwidth to be used, that is, the number of slots to be used can be reduced from the current one.

  Whether or not the modulation format can be changed to a multi-value is determined by quality information such as a signal-to-noise ratio at the wavelength (slot). Therefore, when the wavelength path route and the slot to be used are determined, the control device 2 according to the present embodiment holds quality information on the route, in this example, information for calculating a signal-to-noise ratio. Here, the information for calculating the signal-to-noise ratio includes the loss value for each slot in the optical link, the gain for each slot in the optical amplifier, the noise amount for each slot added by the optical amplifier, etc. Information.

  When the wavelength path # 4 is moved in response to the deletion of the wavelength path # 2 in the state of FIG. 2A, the control device 2 of the present embodiment uses the wavelength of the destination slot # 1. Whether the bandwidth of the wavelength path # 4 can be reduced is determined based on the quality information of the route when the slot # 1 is used. When determining that it is possible, the control device 2 moves the slot of the wavelength path # 4, changes the modulation format of the wavelength path # 4, and changes the occupied band. In this case, the state after defragmentation is as shown in FIG.

  In the state of FIG. 2 (C), it can be seen that fragmentation of the free band is eliminated compared to the state of FIG. 2 (B). For example, in the state of FIG. 2C, a path with an occupied bandwidth of 1 slot can be set between the node device # 2 and the node device # 5, but not in the state of FIG. 2B. is there.

  FIG. 3 is an exemplary configuration diagram of the control device 2 according to the present embodiment. The database unit 21 holds information for calculating the quality information of the wavelength path of an arbitrary path and an arbitrary band of a section. Specifically, information on the loss for each slot of the optical link connecting the node devices 1, the gain for each slot of the optical amplifier used for the node device 1 and the optical link, the amount of added noise, etc. Information necessary for calculating quality information such as information and signal-to-noise ratio is held. Therefore, given the transmission speed necessary for the wavelength path, the path of the wavelength path, and the slot to be used, based on the information held in the database unit 21, it is accommodated within the band of the slot used in the wavelength path, In addition, when the modulation format ensures the necessary transmission rate, the control device 2 can determine whether the necessary quality can be ensured.

  The control unit 22 transmits a control command for controlling the optical network 10 to the optical network 10. More specifically, the control command is transmitted to each node device 1 of the optical network 10. Then, using the wavelength path deletion as a trigger, the determination unit 23 determines the state after the defragmentation process, and controls the optical network 10 so that the state after the defragmentation process determined by the determination unit 23 is obtained. To do.

  The determination unit 23 determines the state after the defragmentation process according to the instruction from the control unit 22. For example, when an unused slot occurs due to deletion of a wavelength path, a wavelength path that is adjacent to the unused slot and is accommodated in a slot with a lower use order than the unused slot is moved to the unused slot. Is determined. Furthermore, the state after the defragmentation process is determined by repeating the same process for the unused slot due to the movement. Further, when a wavelength path that occupies n slots (n is an integer of 2 or more) becomes a movement target, the control unit 22 determines the occupied slot in the movement destination slot of the movement target wavelength path ( It is determined whether it can be changed to n-1) or less, and if the occupied slot can be changed to (n-1) or less, the state in which the occupied slot is changed is set as the state after the defragmentation process.

  In response to the control for deleting the wavelength path, the control unit 22 causes the determination unit 23 to determine the state after the defragmentation process, so that the state after the defragmentation process determined by the determination unit 23 is obtained. However, the present invention is not limited to such a configuration. In response to the control to delete the wavelength path, the determination unit 23 can determine the state after the defragmentation process, and the determination result can be displayed on the display unit (not shown) to notify the maintenance person. . Specifically, for example, when the wavelength path # 2 is deleted in the state of FIG. 2A, depending on whether or not the band of the wavelength path # 4 can be reduced, FIG. 2B or FIG. It can be set as the structure which shows the state of C) to a maintenance person. In this case, the control unit 22 receives the change instruction to the state after the defragmentation process from the maintenance person so that the state after the defragmentation process determined by the determination unit 23 is obtained. To control.

  Further, the control unit 22 does not use the deletion of the wavelength path as a trigger for causing the determination unit 23 to determine the state after defragmentation, but based on an input of a determination instruction for the state after defragmentation from the maintenance person, It is also possible to adopt a configuration in which the state after the defragmentation is determined by 23. Even in this case, the control unit 22 may control the optical network 10 so that the determination unit 23 determines the state without displaying the state after the defragmentation processing determined by the determination unit 23 on the display unit. The state after the defragmentation process determined by the determination unit 23 is displayed on the display unit, and after receiving an explicit change instruction from the maintenance person, the optical network 10 is set to the state determined by the determination unit 23. Can also be controlled.

  The control device 2 according to the present invention can be realized by a program that causes a computer to operate as the control device 2. These computer programs can be stored in a computer-readable storage medium or distributed via a network. Further, the control device 2 can be a single device, or can be realized via a network or the like and / or a plurality of devices capable of direct communication.

Claims (7)

An optical network control device capable of setting wavelength paths of different bandwidths using a basic bandwidth as a slot and using one slot or a plurality of slots that are consecutive in wavelength order,
Holding means for holding information for calculating wavelength path quality information;
A determination means for determining a state after the defragmentation process to prevent fragmentation of unused slots;
A control means for transmitting a control command for controlling the optical network to the optical network and, when a predetermined condition is satisfied, causing the determination means to determine a state after the defragmentation process;
With
The determination means sets the slot usage order, and moves the wavelength path if it can be moved to an unused slot that is adjacent to the wavelength path and has a higher usage order than the wavelength path. If the wavelength path uses a plurality of slots, the holding means determines whether the number of slots used for the wavelength path can be reduced by changing the modulation format of the wavelength path in the moved slot. Is determined based on the quality information calculated from the information held by, and when the number of used slots of the wavelength path can be reduced, the state after defragmentation processing is determined by reducing the number. Control device.   The predetermined condition is that the control unit deletes a wavelength path, or an instruction to determine a state after defragmentation processing is input to the control unit. The control apparatus according to 1.   The control device according to claim 1, wherein the control unit displays a determination result of the determination unit on a display unit.   4. The control device according to claim 1, wherein the control unit controls the optical network so that the state after the defragmentation process determined by the determination unit is achieved. 5.   In response to the input of a change instruction to the state after the defragmentation process determined by the determination unit, the control unit causes the optical network to be in a state after the defragmentation process determined by the determination unit. The control device according to claim 4, wherein the control device is controlled.   The control device according to claim 1, wherein the control device includes a plurality of devices that can communicate with each other.   A program for causing a computer to function as the control device according to any one of claims 1 to 6.

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