JP2017073693A - Optical network controller, optical node device and optical network control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical network controller for suppressing increase in cost of an optical node device by enhancing the utilization efficiency of optical network resources, in an elastic optical network where multiple types of optical path are set.SOLUTION: An optical network controller has network information storage means for storing network information, i.e., the information of an optical link and optical node devices constituting an optical network, and optical path design means for receiving a traffic request, and determining the transmission conditions for each of multiple types of optical path accommodating the traffic request, based on the network information and traffic request, so that the number of types of optical path becoming the same transmission conditions is maximized.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical network control device, an optical node device, and an optical network control method, and more particularly to an optical network control device, an optical node device, and an optical network control method using elastic optical network technology.

  Services for video content with a large information capacity, represented by video streaming services, are rapidly increasing. For this reason, the communication traffic capacity in the network is rapidly expanding. Furthermore, with the rapid spread of such high-function mobile terminals that process such a large amount of content, the amount of fluctuation in communication traffic with respect to changes in time and place is increasing. In the future, as shown by Internet of Things (IoT) technology, this trend is expected to become even more prominent when every digital device has a communication function. Even in such an environment, the network needs to play a role as a social infrastructure that provides a communication function with highly reliable connectivity.

  Against the background of environmental changes described above, new network concepts and network operation methods have been studied (see, for example, Patent Document 1). In the following, an elastic optical network technology, which is a new network concept, and a dynamic network operation method will be described.

  Elastic optical network technology enables more flexible use of wavelength resources in optical fibers. In other words, the elastic optical network technology makes it possible to transmit with the minimum wavelength resources according to the transmission distance to the transfer ground and the transmission throughput by making the modulation method of the optical signal which has been fixed in the past variable. Make it possible. Thereby, the utilization efficiency of optical network resources such as optical fibers can be maximized. Examples of the variable modulation scheme include a QPSK (Quadrature Phase Shift Keying) scheme, an 8QAM (8 Quadrature Amplitude Modulation) scheme, and a 16QAM (16 Quadrature Amplitude Modulation) scheme.

  Another feature of the elastic optical network technology is the introduction of the concept of a fine frequency slot of 12.5 GHz compared to a fixed grid such as 100 GHz (GHz) or 50 GHz. is there. Thereby, the granularity of the wavelength resource to be used can be improved. As a result, it is possible to set the frequency bandwidth to be used with fine granularity by shaping the spectrum shape even with the same modulation scheme.

  On the other hand, with respect to the network operation method, it has been studied to operate the network dynamically, whereas the conventional operation is fixed operation. This is because the amount of fluctuation in communication traffic of clients accommodated in the network is increasing. By dynamically operating the optical network, it becomes possible to allocate network resources without excess or deficiency according to the amount of communication request that varies with time. As a result, useless use of network resources can be reduced, and utilization efficiency of network resources can be improved.

International Publication No. 2011/030897

  In an optical network, the allowable signal-to-noise ratio varies depending on the set communication path length depending on the type of optical path, for example, the active optical path and the redundant optical path in a redundant configuration. Here, the allowable signal-to-noise ratio is an allowable amount of degradation of optical signal quality. When the communication path lengths of the active optical path and the redundant optical path are different, in the optical network (elastic optical network) in which the above-mentioned elastic optical network technology is introduced, the operational optical path and the redundant optical path are used. The modulation scheme can be different. Thereby, the usage amount of the wavelength resource in the optical fiber can be minimized, and the utilization efficiency of the optical network resource can be maximized.

  However, if the modulation method to be used is different, a redundant optical path cannot be generated by optical branching and optical switching of the operational optical path. That is, the optical transceiver included in the optical node device cannot be shared between the active optical path and the redundant optical path. Therefore, it is necessary to provide an extra optical transceiver corresponding to the path that may be set. As a result, the cost of the optical node device increases.

  As described above, in the elastic optical network in which a plurality of types of optical paths are set, there is a problem that the cost of the optical node device increases when the utilization efficiency of the optical network resource is improved.

  An object of the present invention is to solve the above-described problem, that is, in an elastic optical network in which a plurality of types of optical paths are set, the cost of an optical node device increases when the utilization efficiency of optical network resources is improved. An optical network control device, an optical node device, and an optical network control method are provided.

  An optical network control device according to the present invention includes a network information storage means for storing network information, which is information on optical links and optical node devices constituting an optical network, and a plurality of types of optical paths that accept traffic requests and accommodate traffic requests. And an optical path design means that determines the number of types of optical paths that have the same transmission condition based on network information and traffic requirements.

  The optical node device according to the present invention is a transmission condition for each of a plurality of types of optical paths accommodating a traffic request, and the transmission conditions are determined so that the number of types of optical paths that have the same transmission conditions is maximized. Accordingly, it has a function of varying the modulation method of the output optical signal and the optical frequency bandwidth to be used.

  The optical network control method of the present invention acquires the network information, which is information on optical links and optical node devices constituting the optical network, the traffic request, and the transmission conditions of each of a plurality of types of optical paths that accommodate the traffic request. Based on the network information and the traffic request, the number of types of optical paths that have the same transmission condition is determined to be the maximum.

  According to the optical network control device, the optical node device, and the optical network control method of the present invention, an increase in the cost of the optical node device can be suppressed in an elastic optical network in which a plurality of types of optical paths are set.

It is a block diagram which shows the structure of the optical network control apparatus which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structure of the optical node apparatus which concerns on the 2nd Embodiment of this invention, and the structure of the optical network system which consists of an optical network control apparatus and an optical node apparatus. It is a block diagram which shows typically the structure of the optical transmitter / receiver with which the optical node apparatus which concerns on the 2nd Embodiment of this invention is provided. It is a block diagram which shows the structure of the optical network control apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows typically the structure of the setting table with which the optical network control apparatus which concerns on the 2nd Embodiment of this invention is provided. It is a figure which shows typically the structure of the setting table with which the optical network control apparatus which concerns on the 2nd Embodiment of this invention is provided, Comprising: The case where two types of optical paths are set in the same area | region is shown. It is a flowchart for demonstrating operation | movement of the transmission condition determination part with which the optical network control apparatus which concerns on the 2nd Embodiment of this invention is provided. It is a figure which shows typically the structure of the setting table with which the optical network control apparatus which concerns on the 3rd Embodiment of this invention is provided, Comprising: The case where two types of optical paths are set to a different area | region is shown. It is a flowchart for demonstrating operation | movement of the transmission condition determination part with which the optical network control apparatus which concerns on the 3rd Embodiment of this invention is provided. It is a figure which shows typically the structure of the setting table with which the optical network control apparatus which concerns on the 3rd Embodiment of this invention is provided, Comprising: The structure of the setting table after changing is shown. It is a figure which shows typically the structure of the setting table with which the optical network control apparatus which concerns on the 3rd Embodiment of this invention is provided, Comprising: Another structure of the setting table after a change is shown. It is a figure which shows typically the structure of the setting table with which the optical network control apparatus which concerns on the 4th Embodiment of this invention is provided, Comprising: The case where three types of optical paths are set to a different area | region is shown. It is a flowchart for demonstrating operation | movement of the transmission condition determination part with which the optical network control apparatus which concerns on the 4th Embodiment of this invention is provided.

  Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration of an optical network control apparatus 100 according to the first embodiment of the present invention. The optical network control apparatus 100 includes network information storage means 110 and optical path design means 120. The optical network control device 100 is used in an elastic optical network in which a modulation method of an optical signal can be set according to a transmission distance and a transmission capacity (throughput).

  The network information storage unit 110 stores network information that is information on optical links and optical node devices that constitute an optical network. The optical path design unit 120 accepts a traffic request and determines the transmission conditions of each of a plurality of types of optical paths that accommodate the traffic request based on the network information and the traffic request so that the number of types of optical paths that have the same transmission condition is the same. Decide to be the maximum.

  In a plurality of types of optical paths that have the same transmission conditions, it is possible to share an optical transceiver included in an optical node device. Therefore, with the configuration described above, the optical network control device 100 according to the present embodiment can suppress an increase in the cost of the optical node device in an elastic optical network in which a plurality of types of optical paths are set. it can.

  Here, the optical path design means 120 may be configured to determine a plurality of types of optical path generation methods in the optical node device based on the determined transmission conditions. For example, the optical path design unit 120 determines a method for sharing an optical signal transmitted to two routes having the same destination but different routes. Specifically, whether the optical path design unit 120 generates a plurality of optical signals by branching an optical signal output from one optical transceiver, or generates a plurality of optical signals using a plurality of optical transceivers. It can be set as the structure determined to either.

  Note that the transmission conditions described above include at least a modulation scheme, and may further include an optical frequency bandwidth to be used.

  Next, the optical network control method according to the present embodiment will be described. In the optical network control method according to the present embodiment, first, network information, which is information on optical links and optical node devices constituting the optical network, and a traffic request are acquired. Then, the transmission conditions of each of the multiple types of optical paths that accommodate the traffic request are determined based on the network information and the traffic request so as to maximize the number of types of optical paths that have the same transmission condition.

  As described above, the optical transceivers included in the optical node device can be shared by a plurality of types of optical paths that have the same transmission conditions. Therefore, according to the optical network control method according to the present embodiment, an increase in the cost of the optical node device can be suppressed in an elastic optical network in which a plurality of types of optical paths are set.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 2A shows a configuration of an optical node device 400 according to the present embodiment, and a configuration of an optical network system 200 including the optical network control device 300 and the optical node device 400 according to the present embodiment.

  The optical network control device 300 formulates an optical network path and transmission parameters in response to a communication request from a client, and controls the optical node device 400. The optical node device 400 has a function of varying the modulation method of the output optical signal and the optical frequency bandwidth to be used. At this time, the optical node device 400 is the transmission condition of each of the plurality of types of optical paths accommodating the traffic request, and the transmission conditions determined so as to maximize the number of types of optical paths that are the same transmission conditions. The modulation scheme and the optical frequency bandwidth to be used are varied according to the above. In the present embodiment, a case will be described in which the operational optical path 10 and the redundant optical paths 11 and 12 in a redundant configuration are set as a plurality of types of optical paths.

  The optical node device 400 includes an optical transceiver 410, an optical branch switch unit (optical branch switch unit) 420, a client processing unit 430, and an optical node control unit (optical node control unit) 440.

  The optical transceiver 410 sends out an optical signal containing a client signal of an arbitrary capacity using a modulation method according to the capacity. As shown in FIG. 2B, the optical transceiver 410 includes a client interface 411, a framer 412, and a line interface 413. The optical transceiver 410 receives a client signal in the client interface 411, performs a framing process in the framer 412 for wide area transfer, and then transfers the optical signal to the wide area network by the line interface 413. Here, since the line interface 413 includes one laser diode (LD), it is possible to transmit one type of optical carrier per one optical transceiver 410 to the wide area network.

  The above-described three functional units included in the optical transceiver 410 realize a variable accommodation function with respect to the client capacity. That is, the client interface 411 has a function of accommodating an arbitrary capacity. The wide-area transfer framer 412 has a function of performing framing processing in accordance with the size of a variable capacity. The line interface 413 can variably set the modulation method according to the variable capacitance.

  Here, the target modulation schemes include a QPSK modulation scheme, an 8QAM modulation scheme, and a 16QAM modulation scheme. Among these, the optical signal by the 16QAM modulation method has the largest signal multi-value, so that the transmission distance is the shortest, but the optical frequency utilization efficiency is the largest. On the other hand, an optical signal based on the QPSK modulation method has the longest transmission distance because of its low signal multilevel, but the optical frequency utilization efficiency is the smallest.

  The transmission capacity and modulation method of the optical transceiver 410 are controlled by the optical network control device 300 via the optical node control unit 440. Specifically, a high multilevel modulation scheme such as 16QAM is assigned to a short path. On the other hand, a low multilevel modulation scheme such as QPSK is assigned to a long path. As a result, communication requests having different paths and transmission capacities can be transmitted in the minimum optical frequency band.

  The optical branch switch unit 420 performs either an operation of branching or switching an optical signal input to or output from the optical transceiver 410. By branching the optical signal into two, a redundant optical path can be generated from the active optical path. It is also possible to switch from the working optical path to the redundant optical path by switching the destination of the optical signal when a failure occurs.

  The optical branching switch unit 420 needs to be connected in a non-blocking manner between all input / output ports. For this purpose, for example, a commonly used multicast switch can be used. This is because the multicast switch has a non-blocking function in order to select an output port after branching an optical signal once.

  The client processing unit 430 accommodates and processes client data of various granularities from layer 1 to layer 3 in an OSI (Open Systems Interconnection) reference model. It has a function of generating a redundant signal from an operational signal in the state of an electrical signal or a client optical signal.

  The optical node control unit 440 controls the optical transceiver 410, the optical branching switch unit 420, and the client processing unit 430 included in the optical node device 400 based on the setting control command sent from the optical network control device 300.

  Here, the optical node control unit 440 includes the optical transceiver 410 and the optical branching switch unit so that the optical branching switch unit 420 branches the optical signal output from one optical transceiver 410 to generate a plurality of optical signals. 420 is controlled. However, the optical node control unit 440 can also control the optical transceiver 410 and the optical branching switch unit 420 so as to generate a plurality of optical signals using the plurality of optical transceivers 410.

  The optical network control device 300 determines the required number of optical transceivers 410, that is, the number of optical carriers, the transmission conditions such as the modulation method, and the redundant configuration method from the route information of the operation system and the redundant system and the throughput information thereof. Set. Based on this setting control command, the optical node control unit 440 uses the connection port management information in the optical node device 400 to set the settings of the optical transceiver 410, the optical branching switch unit 420, and the client processing unit 430 to be driven. Do.

  Further, the optical node control unit 440 notifies the optical network control device 300 of the operating status of each functional unit included in the optical node device 400.

  FIG. 3 shows the configuration of the optical network control device 300. The optical network control apparatus 300 includes a database unit 310 as a network information storage unit, an optical path design unit (optical path design unit) 320, and an optical path allocation control unit 330.

  The database unit 310 includes a path / link information storage unit 311 that stores information on existing optical paths and links, and an optical node information storage unit 312 that stores resource information of the optical node device 400.

  The optical path design unit 320 includes a route search unit (route search unit) 321, a signal-to-noise ratio calculation unit (signal-to-noise ratio calculation unit) 322, a transmission condition determination unit (transmission condition determination unit) 323, and an allocation order determination unit. 324.

  The route search unit 321 calculates the route of the optical network from the traffic request 20 from the client and the network information stored in the database unit 310. For the calculation of the route, a first-fit algorithm, a most-used algorithm, or the like can be used, but the assignment algorithm is not particularly limited.

  The signal-to-noise ratio calculation unit 322 calculates an allowable signal-to-noise ratio, which is an allowable amount of degradation in optical signal quality, from the calculated path length.

  The transmission condition determination unit 323 determines the transmission conditions for each of the plurality of types of optical paths based on the allowable signal-to-noise ratio and the transmission capacity included in the traffic request 20. At this time, the transmission condition determining unit 323 determines the transmission condition so that the number of types of optical paths that have the same transmission condition is maximized. Specifically, the transmission condition determination unit 323 uses, for example, the allowable signal-to-noise ratio calculated based on the path length and the required transmission capacity as indices, and the modulation scheme of the optical transceiver 410 and the required optical transmission / reception. And a table for setting the number of units 410, that is, the number of optical carriers.

  FIG. 4 schematically illustrates the configuration of a table that is included in the transmission condition determination unit 323 and sets the above-described optical transceiver conditions. In the figure, the horizontal axis indicates the throughput (transmission capacity), and the vertical axis indicates the allowable signal-to-noise ratio. Each area in the figure holds information on the modulation scheme set in the optical transceiver 410 and the number of required optical transceivers. Specifically, for example, the region 31 holds information that employs the QPSK modulation method and uses three optical transceivers (three optical carriers). In the area 32, information that adopts the 8QAM modulation method and uses two optical transceivers (two optical carriers) is held. The area 33 holds information that adopts the 16QAM modulation method and uses one optical transceiver (one optical carrier).

  When the value of the allowable signal-to-noise ratio shown on the vertical axis is large (in the H direction on the vertical axis), transmission with a high multilevel value is possible. On the other hand, when the value of the allowable signal-to-noise ratio is small (J direction on the vertical axis), transmission at a low multi-level is required. Here, the modulation scheme of the optical transceiver 410 and the required number of optical transceivers (number of optical carriers) are set so that the optical frequency band to be used is minimized. That is, the transmission conditions such as the modulation method are determined from the throughput (horizontal axis) and the allowable signal-to-noise ratio (vertical axis), but the optical frequency bandwidth necessary for transmitting the optical signal is the most in the condition of the region 33. It becomes smaller and becomes larger in the order of region 32 and region 31. Therefore, the transmission condition in the area above the vertical axis is selected from the transmission conditions determined by the two axes in FIG.

  As described above, in an elastic optical network, the modulation scheme and the number of optical carriers to be used can be adaptively changed according to the transmission capacity and the allowable signal-to-noise ratio. Therefore, the setting table includes a plurality of setting areas as shown in FIG. Thus, for example, when transmitting the throughput indicated by “D” based on a predetermined traffic request, depending on the allowable signal-to-noise ratio (allowable signal-to-noise ratio), three regions (31, 32, 33) can be set.

  In the region 31, since a permissible signal-to-noise ratio is small, it is necessary to adopt a modulation method with a low multilevel (for example, a QPSK method). On the other hand, the number of optical transceivers (number of optical carriers) required to satisfy the required transmission capacity increases to three. In the region 33, since a permissible signal-to-noise ratio is large, a modulation method with a high multilevel (for example, 16QAM method) can be employed. In this case, the number of required optical transceivers (the number of optical carriers) is reduced. In the area 32, the transmission capability is intermediate between the area 31 and the area 33.

  When setting the active optical path 10 and the redundant optical paths 11 and 12, the path length of the active optical path 10 is generally set shorter in consideration of latency. Therefore, the operational optical path 10 needs to have a higher allowable signal-to-noise ratio. That is, in the setting table shown in FIG. 4, the working optical path 10 is positioned in a region above the vertical axis relative to the redundant optical paths 11 and 12.

  In the following, the communication request from the client includes two types of optical paths, that is, the operational optical path 10 and the redundant optical path 11, and these two types of optical paths are within the same area of the setting table as shown in FIG. The case where it is set to will be described. That is, a case where the optical signals of the active optical path 10 and the redundant optical path 11 are transmitted with the same modulation method and the same optical frequency bandwidth will be described. Such a condition may be, for example, a case where the route of the assigned operational optical path 10 and the redundant optical path 11 are the same distance.

The transmission condition determination unit 323 determines each modulation method and the number of optical carriers to be used for a plurality of types of optical paths such as an operational optical path and a plurality of redundant optical paths. At this time, the transmission condition determining unit 323 performs transmission so that the number of types of optical signals generated by the optical transceiver 410 included in the optical node device 400 among the optical signals accommodated in the plurality of types of optical paths is maximized. Determine the conditions. That is, the transmission condition determining unit 323 determines the transmission conditions such as the modulation scheme so that the sharing degree of the optical transceiver 410 is increased by using information on the throughput of the plurality of types of optical paths and the allowable signal-to-noise ratio. To do. This degree of sharing is represented by the following formula.

  In the above equation, the number of signal types represents the number of signal types such as active and redundant systems. Therefore, for example, when the operating optical path and the redundant optical path are accommodated by a single optical transceiver, the degree of sharing is 200%.

  By using the same transmission conditions (transmission parameters) such as the modulation method and optical frequency bandwidth to be used for multiple types of optical paths, multiple types of optical signals are generated by optical branching or optical switching in the optical branch switch unit 420. It becomes possible to do. Therefore, the sharing degree of the optical transceiver 410 increases.

  After the transmission condition determination unit 323 determines the transmission condition that maximizes the sharing degree of the optical transceiver 410, the allocation order determination unit 324 included in the optical path design unit 320 determines the order of allocation of a plurality of optical path requests. . Then, the optical path allocation control unit 330 notifies the setting command to the optical node device 400 and updates the database unit 310.

  Next, the operation of the transmission condition determination unit 323 will be described in more detail. FIG. 6 is a flowchart for explaining the operation of the transmission condition determination unit 323.

  The transmission condition determination unit 323 receives information on the throughput and the allowable signal-to-noise ratio from the route search unit 321 and the signal-to-noise ratio calculation unit 322 (step S110). A region on the setting table for determining the transmission conditions of the optical transceiver is provisionally determined based on the information and the setting table held (step S120). Then, it is determined whether or not the active optical path 10 and the redundant optical path 11 are included in the same area of the setting table (step S130). If it is determined that they are included in the same area (step S130 / YES), transmission conditions are subsequently determined (step S140). Since the active optical path 10 and the redundant optical path 11 are included in the same area of the setting table, the transmission conditions are determined to be the same as those temporarily determined. In addition, when it determines with not being contained in the same area | region (step S130 / NO), it transfers to the operation | movement flow (step S200) by 3rd Embodiment.

  Next, the transmission condition determination unit 323 determines a method for sharing the optical signals accommodated in the active optical path 10 and the redundant optical path 11 (step S150). Specifically, one of the methods of branching an optical signal output from one optical transceiver to generate a plurality of optical signals, or generating a plurality of optical signals using a plurality of optical transceivers Decide whether to adopt. When the active optical path 10 and the redundant optical path 11 are included in the same area of the setting table, the same modulation scheme is used for the active optical path 10 and the redundant optical path 11, and the optical frequency bandwidth to be used is also It will be the same. For this reason, the sharing method is employed in which the redundant optical path is generated by the optical branching or the optical switch in the state of the optical signal.

  Finally, the transmission condition determination unit 323 notifies the determination result to the optical node device 400 via the optical path allocation control unit 330 (step S160).

  In the above description, two types of optical paths, that is, the operational optical path 10 and the redundant optical path 11 are set. The present invention is not limited to this, and the optical network control device 300 according to the present embodiment is used even when three types of optical paths, that is, the operational optical path 10 and the redundant optical path 11 and the second redundant optical path 12 are set. be able to.

  Next, the optical network control method according to the present embodiment will be described.

  In the optical network control method according to the present embodiment, first, network information, which is information on optical links and optical node devices constituting the optical network, and a traffic request are acquired. Then, the transmission conditions of each of the multiple types of optical paths that accommodate the traffic request are determined based on the network information and the traffic request so as to maximize the number of types of optical paths that have the same transmission condition.

  Here, when determining the transmission conditions described above, first, the route of the optical network is calculated from the traffic request and the network information. From the path length of this path, an allowable signal-to-noise ratio, which is an allowable degradation amount of optical signal quality, is calculated. Based on the transmission capacity and the allowable signal-to-noise ratio included in the traffic request, the transmission conditions for each of the multiple types of optical paths are determined.

  As described above, according to the optical network control device 300, the optical node device 400, and the optical network control method according to the present embodiment, the cost of the optical node device is reduced in an elastic optical network in which a plurality of types of optical paths are set. The increase can be suppressed.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In the third embodiment, the operation of the transmission condition determining unit 323 included in the optical network control device 300 is different from that in the second embodiment. Since the configurations of the optical network control device 300 and the optical node device 400 according to the present embodiment are the same as those according to the second embodiment, their descriptions are omitted.

  Similar to the second embodiment, the transmission condition determination unit 323 includes an optical transceiver setting table. In the present embodiment, the operation of the transmission condition determining unit 323 when the signal-to-noise ratio allowed in the active optical path and the redundant optical path is greatly different will be described. In this case, the active optical path 10 and the redundant optical path 11 are set in different areas of the setting table as shown in FIG. FIG. 7 shows a case where the active optical path 10 is set in the region 33, the transmission parameter is 16QAM, and one carrier transmission is performed by one optical transceiver. On the other hand, the redundant system optical path 11 is set in the area 32, and the transmission parameter is a modulation method of 8QAM and shows a case where two-carrier transmission is performed by two optical transceivers.

  The transmission condition determination unit 323 included in the optical network control device 300 according to the present embodiment performs transmission based on at least one of the utilization information of the optical frequency band in the optical link included in the network information and the margin of the allowable signal-to-noise ratio. Determine the conditions. This network information includes information on existing optical paths and links and resource information on the optical node device 400, and is stored in the database unit 310.

  Next, the operation of the transmission condition determination unit 323 according to this embodiment will be described in more detail. FIG. 8 is a flowchart for explaining the operation of the transmission condition determination unit 323.

  The transmission condition determination unit 323 receives information on the throughput and the allowable signal-to-noise ratio from the route search unit 321 and the signal-to-noise ratio calculation unit 322 (step S110). A region on the setting table for determining the transmission conditions of the optical transceiver is provisionally determined based on the information and the setting table held (step S120). Then, it is determined whether or not the active optical path 10 and the redundant optical path 11 are included in the same area of the setting table (step S130).

  When it is determined that the active optical path 10 and the redundant optical path 11 are not included in the same area of the setting table (step S130 / NO), in the present embodiment, two sharing steps (step S210 and step S220) are performed. Run. By this sharing step, control for improving the sharing degree of the optical transceiver 410 included in the optical node device 400 is performed.

  In the sharing step S210 in the first stage, first, the utilization rate information of the optical frequency band in the target optical link is acquired from the database unit 310 (step S211). Then, it is determined whether there is a margin in the usage status of the optical frequency band (step S212).

  When it is determined that the usage rate of the optical frequency band is equal to or less than a specific threshold value and there is room in usage (step S212 / YES), the transmission condition of the operational optical path 10 is relaxed using the margin of the optical frequency band. The transmission method is determined to have a low multilevel (step S140).

  FIG. 9 shows the setting table after the change in the sharing step S210. An area whose setting has been changed using the margin of the optical frequency band is shown as an extended area 41. As shown in FIG. 7, the active optical path 10 included in the area 33 is included in the extended area 41. Specifically, the operational optical path 10 that has been transmitted with one carrier by one optical transceiver using the 16QAM modulation scheme is transmitted by two carriers by two optical transceivers using the 8QAM modulation scheme. Change the setting as follows. As a result, the operating optical path 10 and the redundant optical path 11 have the same transmission conditions. Under the same transmission conditions, a redundant optical path can be generated by optically branching or optically switching an optical signal in the optical branch switch unit 420, so that the optical transceiver 410 can be shared.

  The threshold value of the usage rate of the optical frequency band used here may be a fixed value or a variable value according to the situation. Further, when the usage status of the optical frequency band is a discontinuous usage status called fragmentation, the free status of the continuous optical frequency band can be used as a threshold value. Further, the block ratio of the optical path may be used as a threshold value.

  On the other hand, when it is determined in step S212 that the usage rate of the optical frequency band exceeds the threshold and there is no room in the usage status of the optical frequency band (step S212 / NO), the process proceeds to the second sharing step S220. .

  In the second sharing step S220, first, margin information of reception sensitivity is calculated (step S221). Here, the margin information of the reception sensitivity is information relating to a wavelength-dependent margin. Since there is a difference in the allowable signal-to-noise ratio for each wavelength of the optical signal, this creates a wavelength dependent margin. The characteristic difference depending on the wavelength of the allowable signal-to-noise ratio is caused by the wavelength dependency of the optical fiber or the optical amplifier. Due to the wavelength dependence of the allowable signal-to-noise ratio, there may be a margin (excess margin) in the allowable signal-to-noise ratio. Therefore, the transmission condition determination unit 323 determines whether there is a margin in the allowable signal-to-noise ratio (step S222).

  When it is determined that the allowable signal-to-noise ratio has a margin (step S222 / YES), this excess margin is used to make the redundant optical path transmission system the same transmission system as the operational optical path. A high transmission method is determined (step S140).

  FIG. 10 shows the setting table after the change in the sharing step S220. A region whose setting is changed using an excessive margin of the allowable signal-to-noise ratio is shown as an extended region 42. As shown in FIG. 7, the redundant optical path 11 included in the region 32 is included in the extended region 42. Specifically, a redundant optical path transmitted by two carriers using two optical transceivers using 8QAM modulation is transmitted by one carrier using one optical transceiver using 16QAM modulation. Change the setting to. As a result, the operating optical path 10 and the redundant optical path 11 have the same transmission conditions. Under the same transmission conditions, a redundant optical path can be generated by optically branching or optically switching an optical signal in the optical branch switch unit 420, so that the optical transceiver 410 can be shared.

  In the above-described two-stage sharing step (steps S210 and S220), if neither condition is satisfied (step S212 / NO and step S222 / NO), a plurality of optical signals are generated using a plurality of optical transceivers. The method is determined (step S150).

  In the above description, after performing step S210 for determining the margin of the usage state of the optical frequency band, step S220 for determining the margin of the allowable signal-to-noise ratio is performed. However, the present invention is not limited to this, and after performing step S220 for determining the margin of the allowable signal-to-noise ratio, step S210 for determining the margin of the usage state of the optical frequency band may be performed.

  As described above, according to the optical network control device 300 according to the present embodiment, the sharing degree of the optical transceiver 410 can be increased. Therefore, in the optical network in which a plurality of types of optical paths are set, the optical node device An increase in cost can be further suppressed.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, the operation of the transmission condition determination unit 323 included in the optical network control device 300 is different from the cases in the second embodiment and the third embodiment. Since the configurations of the optical network control device 300 and the optical node device 400 according to the present embodiment are the same as those according to the second embodiment, their descriptions are omitted.

  Similar to the second embodiment and the third embodiment, the transmission condition determination unit 323 includes an optical transceiver setting table. In the present embodiment, transmission conditions in the case where the allowable signal-to-noise ratio differs greatly in each of the three types of optical paths, ie, the operational optical path 10, the redundant optical path 11, and the second redundant optical path 12. The operation of the determination unit 323 will be described. In this case, the active optical path 10, the redundant optical path 11, and the second redundant optical path 12 are set in different areas of the setting table as shown on the left side of FIG.

  Since the operational optical path 10 has a short path length, the modulation method is a 16QAM method having a large multi-level, and one carrier transmission is performed by one optical transceiver. Therefore, as shown on the left side of FIG. 11, the working optical path 10 is set in the area 33 of the setting table. Since the redundant system optical path 11 has a longer path length than the operational system optical path 10, the modulation system is an 8QAM system with a reduced multi-level, and two-carrier transmission is performed by two optical transceivers. Therefore, the redundant optical path 11 is set in the area 32 of the setting table. Since the second redundant optical path 12 has a longer path length than the redundant optical path 11, the modulation scheme is set to a QPSK scheme with a lower multi-level, and three-carrier transmission is performed by three optical transceivers. . That is, the second redundant optical path 12 is set in the setting table area 31.

  The transmission condition determination unit 323 determines the transmission conditions of the optical transceiver 410 for the active optical path 10, the redundant optical path 11, and the second redundant optical path 12. At this time, the transmission condition determination unit 323 first calculates the extension areas 41 and 42 for each target area of the setting table according to the operation flow (see FIG. 8) according to the third embodiment. The extension area 41 is an area obtained using a margin of the optical frequency band, and the extension area 42 is an area obtained using an excess margin of reception sensitivity.

  Next, the transmission condition determining unit 323 sets at least two or more setting conditions among the setting conditions set for the active optical path 10, the redundant optical path 11, and the second redundant optical path 12, respectively. Are included in the same area of the setting table. The transmission condition determination unit 323 takes into account the expansion areas 41 and 42, and the modulation scheme of the optical transceiver 410 that can be shared with the active optical path 10, the redundant optical path 11, and the second redundant optical path 12. And transmission conditions (transmission parameters) such as the optical frequency band to be used.

  The operation of the transmission condition determination unit 323 at this time will be described in more detail using the flowchart shown in FIG.

  First, the transmission condition determining unit 323 provisionally determines areas on the setting table for the active optical path 10, the redundant optical path 11, and the second redundant optical path 12 (step S310). Then, the margin of the optical frequency band and the excess margin of the reception sensitivity are calculated (step S320).

  Next, it is determined whether or not all optical path setting conditions are included in a single region (step S330). When it is determined that all setting conditions are included in a single area (step S330 / YES), it is then determined whether there are two or more single areas including all setting conditions (step S340). . When it is determined that there are not two or more such single areas (step S340 / NO), the transmission conditions determined for the single area are determined (step S350). That is, the modulation scheme and the number of optical transceivers to be used are determined.

  Next, the transmission condition determining unit 323 determines a method for sharing the optical signals accommodated in the active optical path 10, the redundant optical path 11, and the second redundant optical path 12 (step S360). Specifically, one of the methods of branching an optical signal output from one optical transceiver to generate a plurality of optical signals, or generating a plurality of optical signals using a plurality of optical transceivers Decide whether to adopt. When all the optical paths are included in a single region, the same modulation scheme is used for the active optical path 10, the redundant optical path 11, and the second redundant optical path 12, and the optical frequency bandwidth to be used Are the same. For this reason, the sharing method is employed in which a redundant optical path is generated by optical branching or an optical switch in the state of an optical signal.

  When it is determined that there are two or more single areas including all optical path setting conditions (step S340 / YES), a setting area having a large allowable signal-to-noise ratio is selected (step S341). This is because the use efficiency of the optical frequency is larger under the transmission condition having a larger allowable signal-to-noise ratio.

  Further, when all the optical path setting conditions are not included in the single area (step S330 / NO), it is determined whether two or more setting conditions are included in the same area (step S370). . When it is determined that two or more setting conditions are not included in the same region (step S370 / NO), a method of generating a plurality of optical signals using a plurality of optical transceivers is determined (step S360).

  When it is determined that two or more optical path setting conditions are included in the same area (step S370 / YES), it is subsequently determined whether or not there are two or more single areas including two or more setting conditions. Determination is made (step S380).

  When it is determined that there are two or more single regions including two or more setting conditions (step S380 / YES), a setting region having a large allowable signal-to-noise ratio is selected (step S381). This is because the use efficiency of the optical frequency is larger under the transmission condition having a larger allowable signal-to-noise ratio.

  When it is determined that there are not two or more single areas including two or more setting conditions (step S380 / NO), the transmission conditions determined for the single area are determined (step S350). A sharing method is determined (step S360).

  The right side area of FIG. 11 shows the setting state of the setting table in such a case. It can be seen that by using the extended area 42 of the area 33 for the redundant optical path 11, the operating optical path 10 and the redundant optical path 11 can be set to the same transmission condition. That is, in both the operational optical path 10 and the redundant optical path 11, it is possible to transmit with one carrier by one optical transceiver using the 16QAM modulation method.

  As described above, when the active optical path 10 and the redundant optical path 11 are set in the same area 33 and only the second redundant optical path 12 is set in a different area 31, the active optical path 10 and the redundant optical path are set. The transmission conditions for the path 11 are the same. Therefore, the redundant optical path 11 can be generated from the operational optical path 10 by optically branching or optically switching the optical signal in the optical branch switch unit 420. As a result, the optical transceiver 410 can be shared by the operational optical path 10 and the redundant optical path 11.

  The second redundant optical path 12 that cannot share the optical transceiver 410 is newly formed by the client processing unit 430 included in the optical node device 400, and another optical transceiver is used.

  Even if the redundant optical path 11 and the second redundant optical path 12 are set in the same area of the setting table and only the active optical path 10 is set in a different area, the optical network according to the present embodiment is used. The control device 300 can be used. That is, in this case, since the redundant optical path 11 and the second redundant optical path 12 have the same transmission conditions, a redundant optical path is generated by optically branching or optically switching the optical signal in the optical branch switch unit 420. can do. Therefore, the optical transceiver 410 can be shared by the redundant optical path 11 and the second redundant optical path 12. In this case, the operational optical path 10 that cannot share the optical transceiver is newly formed by the client processing unit 430 included in the optical node device 400.

  As described above, according to the optical network control device 300 according to the present embodiment, the sharing degree of the optical transceiver 410 can be increased. Therefore, in the optical network in which a plurality of types of optical paths are set, the optical node device An increase in cost can be further suppressed.

  The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the invention described in the claims, and it is also included within the scope of the present invention. Not too long.

  A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.

  (Appendix 1) Network information storage means for storing network information, which is information on optical links and optical node devices constituting an optical network, and transmission of each of a plurality of types of optical paths that accept traffic requests and accommodate the traffic requests An optical network control device comprising: an optical path design unit configured to determine a condition based on the network information and the traffic request so that the number of types of the optical path having the same transmission condition is maximized.

  (Supplementary note 2) The optical network control device according to supplementary note 1, wherein the optical path design unit determines a generation method of the plurality of types of optical paths in the optical node device based on the determined transmission condition.

  (Supplementary Note 3) The optical path design means is a path search means for calculating a route of the optical network from the traffic request and the network information, and an allowable optical signal quality degradation amount from the route length of the route. Signal-to-noise ratio calculating means for calculating a certain allowable signal-to-noise ratio, and determining the transmission conditions for each of the plurality of types of optical paths based on the transmission capacity included in the traffic request and the allowable signal-to-noise ratio An optical network control device according to appendix 1 or 2, comprising transmission condition determination means for

  (Supplementary Note 4) The transmission condition determining means determines the transmission condition based on at least one of utilization information of an optical frequency band in the optical link included in the network information and a margin of the allowable signal-to-noise ratio. The optical network control device described in appendix 3.

  (Supplementary Note 5) According to the transmission conditions of each of a plurality of types of optical paths that accommodate traffic requests, the transmission conditions determined so as to maximize the number of types of the optical paths that are the same transmission conditions, An optical node device having a function of varying a modulation method of an optical signal to be output and an optical frequency bandwidth to be used.

  (Supplementary note 6) An optical transceiver for transmitting an optical signal containing a client signal of an arbitrary capacity using a modulation method according to the capacity, an operation for branching an optical signal to be input to and output from the optical transceiver, and Item 5. The optical branching switch unit that performs any one of the switching operations, and the optical node control unit that respectively controls the optical transceiver and the optical branching switch unit based on the determined transmission condition. Optical node equipment.

  (Supplementary note 7) The optical node control unit and the optical branching unit are configured to branch the optical signal output from one optical transceiver by the optical branching switch unit to generate a plurality of optical signals. The optical node device according to appendix 6, which controls the switch means.

  (Supplementary note 8) The optical node according to supplementary note 6, wherein the optical node control unit controls the optical transceiver and the optical branching switch unit so as to generate a plurality of optical signals using the plurality of optical transceivers. apparatus.

  (Additional remark 9) The network information which is the information of the optical link which comprises an optical network, and an optical node apparatus, a traffic request | requirement, and each transmission condition of the multiple types of optical path which accommodates the said traffic request | requirement is said network information. And an optical network control method for determining, based on the traffic request, such that the number of types of the optical paths having the same transmission condition is maximized.

  (Supplementary Note 10) When determining the transmission conditions, a route of the optical network is calculated from the traffic request and the network information, and an allowable amount of degradation in optical signal quality that is allowed from the route length of the route The optical network control method according to appendix 9, wherein a signal-to-noise ratio is calculated, and transmission conditions of each of the plurality of types of optical paths are determined based on a transmission capacity included in the traffic request and the allowable signal-to-noise ratio. .

  (Supplementary Note 11) The transmission condition determining unit may maximize the number of types of the optical signal generated by the optical transceiver included in the optical node device among the optical signals accommodated in the plurality of types of optical paths. The optical network control device according to appendix 3, wherein the transmission condition is determined.

  (Supplementary note 12) The optical network control device according to any one of supplementary notes 1 to 4 and 11, wherein the transmission condition includes at least a modulation method.

  (Supplementary note 13) The optical network control device according to supplementary note 12, wherein the transmission condition further includes an optical frequency bandwidth.

  (Supplementary note 14) The optical network control device according to any one of supplementary notes 1 to 4, and 11 to 13, wherein the plurality of types of optical paths include an operational optical path and a redundant optical path in a redundant configuration.

  (Supplementary note 15) When determining the transmission condition, based on at least one of utilization information of an optical frequency band in the optical link included in the network information and a margin of the allowable signal-to-noise ratio, the transmission condition The optical network control method according to appendix 10, wherein:

DESCRIPTION OF SYMBOLS 100 Optical network control apparatus 110 Network information storage means 120 Optical path design means 200 Optical network system 300 Optical network control apparatus 310 Database part 311 Path / link information storage part 312 Optical node information storage part 320 Optical path design part 321 Route search part 322 Signal-to-noise ratio calculation unit 323 Transmission condition determination unit 324 Allocation order determination unit 330 Optical path allocation control unit 400 Optical node device 410 Optical transceiver 411 Client interface 412 Framer 413 Line interface 420 Optical branch switch unit 430 Client processing unit 440 Optical node Control unit 10 Active optical path 11 Redundant optical path 12 Second redundant optical path 20 Traffic request 31, 32, 33 area 41, 42 Extended area

Claims (10)

Network information storage means for storing network information, which is information on optical links and optical node devices constituting an optical network;
Based on the network information and the traffic request, the number of types of the optical path that has the same transmission condition is maximized based on the network information and the traffic request. An optical network control device comprising: an optical path design means for determining The optical network control device according to claim 1, wherein the optical path design unit determines a generation method of the plurality of types of optical paths in the optical node device based on the determined transmission condition. The optical path design means includes:
Route search means for calculating a route of the optical network from the traffic request and the network information;
A signal-to-noise ratio calculating means for calculating an allowable signal-to-noise ratio that is an allowable amount of degradation in optical signal quality from the path length of the path;
The transmission condition determining means for determining the transmission condition of each of the plurality of types of optical paths based on a transmission capacity included in the traffic request and the allowable signal-to-noise ratio. Optical network controller. 4. The transmission condition determining unit determines the transmission condition based on at least one of usage rate information of an optical frequency band in the optical link included in the network information and a margin of the allowable signal-to-noise ratio. The optical network control device described in 1. Optical signals to be output in accordance with transmission conditions of each of a plurality of types of optical paths that accommodate traffic requests and determined so as to maximize the number of types of the optical paths that have the same transmission conditions An optical node device having a function of varying the modulation method and optical frequency bandwidth to be used. An optical transceiver for transmitting an optical signal containing a client signal of an arbitrary capacity using a modulation method according to the capacity;
An optical branching switch means for performing either an operation of branching or an operation of switching an optical signal input to or output from the optical transceiver;
The optical node device according to claim 5, further comprising: an optical node control unit that controls the optical transceiver and the optical branching switch unit based on the determined transmission condition. The optical node control means controls the optical transceiver and the optical branch switch means so that an optical signal output from one optical transceiver is branched by the optical branch switch means to generate a plurality of optical signals. The optical node device according to claim 6. The optical node device according to claim 6, wherein the optical node control unit controls the optical transceiver and the optical branch switch unit so as to generate a plurality of optical signals using the plurality of optical transceivers. Obtain network information, which is information on optical links and optical node devices that make up an optical network, and traffic requests.
Based on the network information and the traffic request, the transmission conditions of each of a plurality of types of optical paths that accommodate the traffic request are determined so that the number of types of the optical paths that have the same transmission condition is maximized. Network control method. In determining the transmission conditions,
From the traffic request and the network information, calculate the route of the optical network,
From the path length of the path, calculate an allowable signal-to-noise ratio that is an allowable amount of optical signal quality degradation,
The optical network control method according to claim 9, wherein transmission conditions for each of the plurality of types of optical paths are determined based on a transmission capacity included in the traffic request and the allowable signal-to-noise ratio.

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