JP7713862B2 - Control device and program - Google Patents

Description

The present disclosure relates to a control device and a program .

In an optical network, multiple optical signals are communicated. For example, an optical network is described in Patent Document 1. Here, a technology is proposed for rearranging the wavelengths of optical signals (see Patent Document 2). For example, the network design device in Patent Document 2 rearranges optical lines to each optical wavelength based on design information that arranges optical lines for each optical wavelength in the network.

Patent No. 6658511 JP 2017-143424 A

However, when a fault occurs on a route within an optical network, communication via that route becomes impossible. Therefore, the route is switched to another route, allowing communication to continue. When switching routes, the route after the switch may be assigned a wavelength different from the wavelength assigned to the route before the switch. In detail, wavelength assignment is performed based on rules. However, depending on the content of the rules, it may not be possible to maximize the number of wavelengths available in the optical network.

The objective of this disclosure is to maximize the use of the number of wavelengths available in an optical network.

A control device according to one aspect of the present disclosure is provided. The control device switches paths by controlling optical switches included in a plurality of nodes that construct an optical mesh network, and includes a control unit that switches paths and assigns a plurality of wavelengths based on control information. When a fault is detected in the optical mesh network, the control unit excludes the path in which the fault has occurred from the path to be switched to, and when a path is switched back, assigns wavelengths so as to prevent wavelength collisions, and performs switching and wavelength assignment by giving priority to a path among the plurality of paths in the optical mesh network through which an optical signal in which a plurality of optical signals are multiplexed is communicated, or performs path switching and wavelength assignment in descending order of the number of nodes included in the path after switching, and assigns wavelengths based on a First-Fit method, or performs wavelength assignment based on the number of nodes included in the path after switching and the number of nodes corresponding to the path after switching. The control information is to switch routes and allocate wavelengths in descending order of evaluation value calculated based on a bandwidth and to allocate wavelengths based on a First-Fit method, or the control unit allocates wavelengths so as to prevent wavelength collisions when a route is switched back before a failure occurs in the optical mesh network, and to give priority to a route through which an optical signal in which a plurality of optical signals are multiplexed is communicated among a plurality of routes in the optical mesh network, and to set the reservation route for the route through which the multiplexed optical signal is communicated and the wavelength to be allocated to the reservation route.

This disclosure allows maximum use of the number of wavelengths available in an optical network.

FIG. 1 illustrates an optical communication system according to a first embodiment. 1A and 1B are diagrams showing a comparative example (1-1). 1A and 1B are diagrams showing a comparative example (1-2). FIG. 2 is a diagram illustrating hardware included in a control device according to the first embodiment. 2 is a block diagram showing the functions of a control device according to the first embodiment; FIG. 13A and 13B are diagrams illustrating a specific example (1-1) of processing executed by the control device of the first embodiment. 13A and 13B are diagrams illustrating a specific example (1-2) of processing executed by the control device of the first embodiment. A figure showing a specific example (1-3) of processing executed by the control device of embodiment 1. 2A and 2B are diagrams showing a comparative example (2-1). 13A and 13B are diagrams showing a comparative example (2-2). FIG. 11 is a block diagram showing the functions of a control device according to a second embodiment. 13A and 13B are diagrams illustrating a specific example (2-1) of processing executed by the control device of the second embodiment. 13A and 13B are diagrams illustrating a specific example (2-2) of processing executed by the control device of the second embodiment. A figure showing a specific example (2-3) of processing executed by the control device of embodiment 2. A figure showing an example in which a reservation path in embodiment 3 is determined. 13A and 13B are diagrams showing a comparative example (3). FIG. 11 is a block diagram showing the functions of a control device according to a third embodiment. 13A and 13B are diagrams illustrating a specific example (3) of processing executed by the control device of the third embodiment.

The following describes an embodiment with reference to the drawings. The following embodiment is merely an example, and various modifications are possible within the scope of this disclosure.

Embodiment 1.
1 is a diagram showing an optical communication system according to a first embodiment. The optical communication system includes a control device 100 and a plurality of nodes. The optical communication system may also include a data center 10 and an SDH (Synchronous Digital Hierarchy) ring 20. An optical mesh network 200 is constructed with a plurality of nodes.
The control device 100 monitors a plurality of nodes and also controls the plurality of nodes.

FIG. 1 shows that communication between the data center 10 and the SDH ring 20 is performed via an optical mesh network 200. For example, communication between the data center 10 and the SDH ring 20 is performed via a path X1. A failure may occur in the optical mesh network 200. For example, the failure is a failure in an optical cable between nodes. When a failure occurs in the optical mesh network 200, the control device 100 can switch paths by controlling optical switches in multiple nodes. For example, the control device 100 switches from path X1 to path X2 by controlling optical switches in some nodes. As a result, even if a failure occurs in the optical mesh network 200, communication continues between the data center 10 and the SDH ring 20.

Next, a comparative example will be described.
2A and 2B are diagrams showing a comparative example (1-1). FIG. 2 shows nodes A to F. An optical mesh network is constructed with nodes A to F. In the optical mesh network, it is possible to use wavelengths λ1 to λ6 with a bandwidth of 50 GHz.

The route between nodes A and D is called route R1. Nodes A and D communicate a 50 GHz λ1 optical signal. The route between nodes C, B, E, and F is called route R2. Nodes C, B, E, and F communicate a 50 GHz λ4 optical signal and a 50 GHz λ5 optical signal. The route between nodes A, B, E, and D is called route R3. Nodes A, B, E, and D communicate a 150 GHz λ1-3 optical signal (i.e., the total bandwidth of the three wavelengths). The λ1-3 optical signal is a multiplexed signal of three optical signals.

Figure 2 (A) shows that a fault has occurred in the route between nodes A and D and the route between nodes B and E. In this way, when a fault occurs, the optical mesh network switches routes. Here, route switching and wavelength allocation are performed based on three rules. First, route switching means temporary evacuation. Therefore, when the fault is overcome, the switched route is returned to the original route. In other words, the route is switched back. Rule 1 is established to prevent wavelength collisions when the route is switched back. Rule 1 is to assign wavelengths so that wavelength collisions do not occur when the route is switched back. In detail, rule 1 is to assign a wavelength different from the wavelength assigned to the second route to a third route in which at least a part of the second route is the same route and the route to be switched is switched. Rule 2 is to assign wavelengths based on a wavelength assignment algorithm (i.e., the First-Fit method). In other words, rule 2 assigns wavelengths in ascending order of numbers. Rule 3 says that wavelengths that are being assigned to other paths cannot be assigned.

Below, we will explain the case where route switching is performed based on the above three rules. Figure 2 (B) shows the state after Figure 2 (A). Route R1 is switched to route R4. Route R4 is a route between nodes A, B, C, F, E, and D. λ6 is assigned to route R4 based on rules 1 and 3.

Figures 3 (A) and (B) are diagrams showing a comparative example (1-2). Figure 3 (A) shows the state after Figure 2 (B). Route R2 is switched to route R5. Route R5 is a route between nodes C and F. λ1 and λ2 are assigned to route R5 based on rules 1 and 2.

Figure 3 (B) shows the state after Figure 3 (A). When route R3 is switched to the route of nodes A, B, C, F, E, and D, λ3-5 is assigned to that route based on rule 2. Here, when the obstacle is overcome, route R5 is switched to route R2. λ4 and λ5 are assigned to route R2. λ4 and λ5 among λ3-5 communicated on that route collide with λ4 and λ5 communicated on route R2. Therefore, the method of switching route R3 to the route of nodes A, B, C, F, E, and D and assigning wavelengths based on rule 2 does not satisfy rule 1. Therefore, route R3 cannot be switched. Therefore, λ3-5 is no longer used in the optical mesh network. Therefore, this method does not maximize the number of wavelengths available in the optical network.

Below, we explain how to maximize the number of wavelengths available in an optical network.

Next, the hardware of the control device 100 will be described.
4 is a diagram showing hardware included in the control device of embodiment 1. The control device 100 includes a processor 101, a volatile storage device 102, and a non-volatile storage device 103.

The processor 101 controls the entire control device 100. For example, the processor 101 is a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), or the like. The processor 101 may be a multiprocessor. The control device 100 may also have a processing circuit.

The volatile memory device 102 is the main memory device of the control device 100. For example, the volatile memory device 102 is a RAM (Random Access Memory). The non-volatile memory device 103 is an auxiliary memory device of the control device 100. For example, the non-volatile memory device 103 is a HDD (Hard Disk Drive) or an SSD (Solid State Drive).

Next, the functions of the control device 100 will be described.
5 is a block diagram showing the functions of the control device according to embodiment 1. The control device 100 includes a storage unit 110, a monitoring unit 120, and a control unit 130.

The storage unit 110 may be realized as a storage area secured in the volatile storage device 102 or the non-volatile storage device 103 .
The monitoring unit 120 and the control unit 130 may be partly or entirely implemented by a processing circuit, or partly or entirely implemented as a program module executed by the processor 101.

The storage unit 110 stores control information 111. The control information 111 includes a first rule that indicates that a path in which a failure has occurred should be excluded from paths to be switched to.
The control information 111 includes a second rule indicating that wavelengths are assigned so as to avoid wavelength collisions when a route is switched back. The second rule is the same as rule 1 in the comparative example.
The control information 111 includes a third rule indicating that switching and wavelength allocation should be performed with priority given to a route among multiple routes within the optical mesh network 200, the route through which an optical signal in which multiple optical signals are multiplexed is communicated.

The monitoring unit 120 monitors the optical mesh network 200 .
When a fault is detected in the optical mesh network 200 by the monitoring unit 120, the control unit 130 switches the route and assigns a plurality of wavelengths based on the control information 111. For example, when switching the route, the control unit 130 transmits a switching instruction to a node on the route from which the route is to be switched and a node on the route to which the route is to be switched. This causes the route to be switched. The control unit 130 also transmits an instruction to a node on the route to which the route is to be switched so that an optical signal of the assigned wavelength can move.

Next, the processing of the control device 100 will be described using a concrete example.
6A and 6B are diagrams showing a specific example (1-1) of the process executed by the control device of embodiment 1. The state of Fig. 6A is the same as the state of Fig. 2A.
The monitoring unit 120 detects that a failure has occurred on the path between nodes A and D and on the path between nodes B and E.
Since a fault has been detected, the control unit 130 performs route switching and allocation of multiple wavelengths based on the control information 111. Based on the first rule, the control unit 130 excludes the route between nodes A and D and the route between nodes B and E from the route to be switched to.

Figure 6 (B) shows the state after Figure 6 (A). The control unit 130 switches the route and assigns multiple wavelengths based on the third rule. Specifically, the control unit 130 switches route R3 to route R4 based on the third rule. Route R4 is a route between nodes A, B, C, F, E, and D. The control unit 130 assigns λ1-3 to route R4. Furthermore, the allocation of λ1-3 to route R4 complies with the second rule.

Figures 7 (A) and (B) are diagrams showing a specific example (1-2) of the processing executed by the control device of embodiment 1. Figure 7 (A) shows the state after Figure 6 (B). The control unit 130 switches route R1 to route R5. Route R5 is a route between nodes A, B, C, F, E, and D. The control unit 130 assigns λ6 to route R5 based on the second rule.

Figure 7 (B) shows the state after Figure 7 (A). The control unit 130 switches route R2 to route R6. Route R6 is a route between nodes C and F. The control unit 130 assigns λ4 and λ5 to route R6 based on the second rule.

Fig. 8 is a diagram showing a specific example (1-3) of the process executed by the control device of embodiment 1. Fig. 8 shows the state after Fig. 7(B).
The next state of Fig. 6(B) may be the state of Fig. 7(B). The next state of Fig. 7(B) may be the state of Fig. 7(A). The next state of Fig. 7(A) may be the state of Fig. 8.

According to the first embodiment, the control device 100 uses the control information 111 to switch paths and assign wavelengths, thereby maximizing the number of wavelengths available in the optical network.

Embodiment 2.
Next, a description will be given of embodiment 2. In embodiment 2, differences from embodiment 1 will be mainly described. Furthermore, in embodiment 2, description of matters common to embodiment 1 will be omitted.

First, a comparative example will be described.
9A and 9B are diagrams showing a comparative example (2-1). FIG. 9 shows nodes A to F. An optical mesh network is constructed with nodes A to F. In the optical mesh network, it is possible to use wavelengths λ1 to λ6 with a bandwidth of 50 GHz.

The route between nodes A, B, E, and D is called route R1. Nodes A, B, E, and D communicate a λ1-3 optical signal of 150 GHz (i.e., the total bandwidth of the three wavelengths). The λ1-3 optical signal is a multiplexed signal of three optical signals. The route between nodes C, B, E, and F is called route R2. Nodes C, B, E, and F communicate a λ5 optical signal of 50 GHz and a λ6 optical signal of 50 GHz. The route between nodes A and D is called route R3. Nodes A and D communicate a λ1 optical signal of 50 GHz.

9A shows that a failure has occurred on the route between nodes A and D and the route between nodes B and E. Because of the failure, the route is switched. The route switching and wavelength allocation are performed based on rules 1 and 2 described in FIG.
9B shows the state after FIG. 9A. Route R1 is switched to route R4. Route R4 is a route between nodes A, B, C, F, E, and D. λ1-3 is assigned to route R4 based on rules 1 and 2.

Figures 10 (A) and (B) are diagrams showing a comparative example (2-2). Figure 10 (A) shows the state after Figure 9 (B). Route R2 is switched to route R5. Route R5 is a route between nodes C and F. λ4 and λ5 are assigned to route R5 based on rules 1 and 2.

Figure 10 (B) shows the state after Figure 10 (A). When route R3 is switched to the route of nodes A, B, C, F, E, and D, λ6 is assigned to that route based on rule 2. Here, if the failure is overcome, route R5 is switched to route R2. λ5 and λ6 are assigned to route R2. λ6 communicated on that route and λ6 communicated on route R2 collide. Therefore, the method of switching route R3 to the route of nodes A, B, C, F, E, and D does not satisfy rule 1. Therefore, route R3 cannot be switched. Therefore, λ6 is no longer used in the optical mesh network. Therefore, this method does not maximize the number of wavelengths available in the optical network.

Below, we explain how to maximize the number of wavelengths available in an optical network.

Figure 11 is a block diagram showing the functions of a control device according to the second embodiment. The components in Figure 11 that are the same as those in Figure 5 are given the same reference numerals as those in Figure 5. The control device 100a has a memory unit 110a and a control unit 130a.

The storage unit 110a stores control information 111a, which includes a first rule indicating that a path in which a failure has occurred should be excluded from paths to be switched to.
The control information 111a includes a second rule indicating that wavelengths should be assigned so as to avoid wavelength collisions when a route is switched back.
The control information 111a includes a third rule that indicates that after switching and wavelength allocation are performed with priority given to a route through which an optical signal in which multiple optical signals are multiplexed is communicated, route switching and wavelength allocation are performed in order of the number of nodes included in the route after switching.
The control information 111a includes a fourth rule that indicates that wavelengths are to be assigned based on the First-Fit method.
The control information 111a includes a fifth rule which indicates that switching and wavelength allocation should be performed with priority given to a route among multiple routes within the optical mesh network 200, through which an optical signal in which multiple optical signals are multiplexed is communicated.

When a fault is detected in the optical mesh network 200, the control unit 130a switches the route and assigns multiple wavelengths based on the control information 111a.

Next, the processing of the control device 100a will be described using a specific example.
12A and 12B are diagrams showing a specific example (2-1) of the process executed by the control device of embodiment 2. The state of FIG. 12A is the same as the state of FIG.
The monitoring unit 120 detects that a failure has occurred on the path between nodes A and D and on the path between nodes B and E.
Since a fault has been detected, the control unit 130a performs route switching and allocation of multiple wavelengths based on the control information 111a. Based on the first rule, the control unit 130a excludes the route between nodes A and D and the route between nodes B and E from the route to be switched to.

Figure 12 (B) shows the state after Figure 12 (A). Based on the fifth rule, the control unit 130a switches route R1 to route R4. Route R4 is a route between nodes A, B, C, F, E, and D. Based on the fourth and fifth rules, the control unit 130a assigns λ1-3 to route R4. In addition, the assignment of λ1-3 to route R4 complies with the second rule.

Figures 13(A) and (B) are diagrams showing a specific example (2-2) of the processing executed by the control device of embodiment 2. Figure 13(A) shows the state after Figure 12(B).

The control unit 130a switches routes and assigns wavelengths based on the second, third, and fourth rules. Specifically, since the fifth rule has been applied, the control unit 130a determines the order of route switching based on the third rule. Here, when route R3 is switched, the number of nodes included in the route after switching is six (i.e., six nodes A, B, C, F, E, and D). When route R2 is switched, the number of nodes included in the route after switching is two (i.e., two nodes C and F). Therefore, the control unit 130a decides to switch route R2 after switching route R3. The control unit 130a switches route R3 to route R5. Route R5 is a route of nodes A, B, C, F, E, and D. The control unit 130a assigns λ4 to route R5 based on the second and fourth rules.

Figure 13 (B) shows the state after Figure 13 (A). The control unit 130a switches route R2 to route R6. Route R6 is a route between nodes C and F. The control unit 130a assigns λ5 and λ6 to route R6 based on the second and fourth rules.

Figure 14 is a diagram showing a specific example (2-3) of the processing executed by the control device of embodiment 2. Figure 14 shows the state after Figure 13 (B).

According to the second embodiment, the control device 100a uses the control information 111a to switch paths and assign wavelengths, thereby maximizing the number of wavelengths available in the optical network.

In addition, the control information 111a does not have to include the fifth rule. If the fifth rule is not included in the control information 111a, the third rule indicates that the route is switched and wavelengths are assigned in descending order of the number of nodes included in the route after switching. For example, if a multiplexed optical signal does not travel through the optical mesh network 200, the control device 100a switches the route and assigns multiple wavelengths using control information 111a that does not include the fifth rule.

Furthermore, the control information 111a may indicate the following contents. The control information 111a includes a first rule indicating that a route in which a failure has occurred is to be excluded from the route to be switched. The control information 111a includes a second rule indicating that wavelengths are assigned so as to prevent wavelength collisions when a route is switched back. The control information 111a includes a third rule indicating that route switching and wavelength assignment are performed in descending order of evaluation values calculated based on the number of nodes included in the route after switching and the bandwidth corresponding to the route after switching. The control information 111a includes a fourth rule indicating that wavelengths are assigned based on the First-Fit method. For example, the control unit 130a calculates the evaluation value when the optical mesh network 200 is in the state of FIG. 12 (A). Specifically, the control unit 130a calculates an evaluation value of "900 (=6×150)" based on the number of nodes included in the route after switching the route R1 (i.e., six nodes A, B, C, F, E, and D) and the bandwidth corresponding to the route after switching (i.e., 150 GHz (=50 GHz×3)). The control unit 130a calculates an evaluation value of "100 (=2×50)" based on the number of nodes included in the route after switching the route R2 (i.e., two nodes C and F) and the bandwidth corresponding to the route after switching (i.e., 50 GHz). The control unit 130a calculates an evaluation value of "300 (=6×50)" based on the number of nodes included in the route after switching the route R3 (i.e., six nodes A, B, C, F, E, and D) and the bandwidth corresponding to the route after switching (i.e., 50 GHz). Therefore, the control unit 130a determines to perform route switching and wavelength allocation in the order of route R1, route R3, and route R2. After this, route switching and wavelength allocation are performed in the same manner as in FIG. 12(B), FIG. 13(A), and (B). Therefore, the control device 100a can maximize the number of wavelengths available in the optical network by performing route switching and wavelength allocation using the control information 111a.

Embodiment 3.
Next, a description will be given of embodiment 3. In embodiment 3, differences from embodiment 1 will be mainly described. Furthermore, in embodiment 3, description of matters common to embodiment 1 will be omitted.
In the first and second embodiments, a route is determined and switched after a failure occurs. In the third embodiment, a case in which a route to be switched to is determined in advance will be described.

First, we will explain the case where the destination route has been determined in advance. Here, the destination route is called the reserved route.

Figure 15 is a diagram showing an example in which a reservation path in embodiment 3 has been determined. Figure 15 shows nodes A to I. The path between nodes A, B, and C is path Y1. An optical signal of λ1 is communicated on path Y1. The path between nodes G, H, and I is path Y2. An optical signal of λ1 is communicated on path Y2.

The route between nodes A, D, E, F, and C is reservation route Z1. The route between nodes G, D, E, F, and I is reservation route Z2.
If a fault occurs on the path between node B and node C, path Y1 switches to reserved path Z1. Here, node F has an RGN (Regenerator). The RGN can switch wavelengths. Therefore, for example, when an optical signal of λ1 is input to node F, the optical signal of λ1 is switched to an optical signal of another wavelength.

Next, a comparative example of a method for determining a reservation path will be described.
16A and 16B are diagrams showing a comparative example (3). Fig. 16A shows nodes A to F. An optical mesh network is constructed with nodes A to F. In the optical mesh network, wavelengths λ1 to λ6 with a bandwidth of 50 GHz can be used.

The route between nodes A, D, and E is called route R1. Nodes A, D, and E communicate a 50 GHz λ4 optical signal and a 50 GHz λ5 optical signal. The route between nodes C, F, E, and D is called route R2. Nodes C, F, E, and D communicate a 50 GHz λ6 optical signal. The route between nodes D, E, and F is called route R3. Nodes D, E, and F communicate a 150 GHz λ1-3 optical signal (i.e., the sum of the bandwidths of the three wavelengths). The λ1-3 optical signal is a multiplexed signal of three optical signals.

Reserved routes are set up in the optical mesh network. Wavelengths are assigned to the reserved routes. Two rules are used to set the wavelengths to be assigned to reserved routes. Rule 1 is to assign wavelengths so that there is no wavelength collision when a route is switched back. Rule 2 is to assign wavelengths based on a wavelength assignment algorithm (i.e., the First-Fit method). Rule 3 is to assign wavelengths so that there is no overlapping of wavelengths assigned to reserved routes.

Figure 16 (B) shows the setting of reservation routes. Route R4 is set as the reservation route for route R1. Route R4 (reservation route) is a route between nodes A, B, and E. λ1 and λ2 are assigned to route R4 (reservation route) based on rules 1 and 2. Route R5 is set as the reservation route for route R2. Route R5 (reservation route) is a route between nodes D, A, B, and C. λ3 is assigned to route R5 (reservation route) based on rules 1 and 2.

Route R6 is set as a reservation route for route R3. Route R6 (reservation route) is a route for nodes D, A, B, C, and F. Here, if λ4-6 are assigned to route R6 (reservation route) based on rule 2, λ4 and λ5 of route R6 (reservation route) collide with λ4 and λ5 of route R1. That is, if a failure occurs and route R3 switches to route R6 (reservation route), λ4 and λ5 of route R6 (reservation route) collide with λ4 and λ5 of route R1. Therefore, RGNs are installed in nodes A and C. If λ1-3 is assigned to the route for nodes A and D and the route for nodes C and F, the route for nodes A, B, and C switches to λ4-6. This avoids collision between λ4 and λ5 of route R6 (reservation route) and λ4 and λ5 of route R1. On the other hand, if a failure occurs, λ3 of route R5 (reservation route) will collide with λ3 of route R6 (reservation route). That is, a collision will occur on the route between nodes A and D. This violates rule 3.
Thus, in an optical mesh network, there are wavelengths that cannot be used, and therefore this method does not maximize the number of wavelengths available in the optical network.

Below, we explain how to maximize the number of wavelengths available in an optical network.

Fig. 17 is a block diagram showing the functions of a control device according to embodiment 3. The components in Fig. 17 that are the same as those in Fig. 5 are given the same reference numerals as those in Fig. 5. The control device 100b has a storage unit 110b and a control unit 130b.
The storage unit 110b stores control information 111b.

The control information 111b includes a first rule indicating that wavelengths should be assigned so as to avoid wavelength collisions when a route is switched back.
The control information 111b includes a second rule indicating that, among multiple routes within the optical mesh network 200, a route through which an optical signal in which multiple optical signals are multiplexed is communicated is given priority, and a reservation route for that route and a wavelength to be assigned to that reservation route are set.

Before a failure occurs in the optical mesh network 200, the control unit 130b sets the reserved path to which the path is switched and the wavelength to be assigned to the reserved path based on the control information 111b.

Next, the processing of the control device 100b will be described using a specific example.
18A and 18B are diagrams showing a specific example (3) of the process executed by the control device of embodiment 3. The state of FIG. 18A is the same as the state of FIG.
The control unit 130b sets a reservation path based on the second rule. Specifically, the control unit 130b sets route R4 as a reservation path for route R3 based on the second rule. Route R4 (reservation path) is a path between nodes D, A, B, C, and F. The control unit 130b assigns λ1-3 to route R4 (reservation path) based on the first rule. Note that no RGN is installed in nodes A and C.

The control unit 130b sets route R5 as a reserved route for route R2. Route R5 (reserved route) is a route between nodes D, A, B, and C. The control unit 130b assigns λ6 to route R5 (reserved route) based on the first rule.
The control unit 130b sets route R6 as a reserved route for route R1. Route R6 (reserved route) is a route between nodes A, B, and E. The control unit 130b assigns λ4 and λ5 to route R6 (reserved route) based on the first rule.

According to the third embodiment, the control device 100b uses the control information 111b to set a reserved path and a wavelength to be assigned to the reserved path. As a result, when a failure occurs, the optical network uses the maximum number of wavelengths available in the optical network. In addition, no RGN is installed in the node. This reduces the cost of the node.

The features of each of the embodiments described above can be combined as appropriate.

10 Data center, 20 SDH ring, 100, 100a, 100b Control device, 101 Processor, 102 Volatile storage device, 103 Non-volatile storage device, 110, 110a, 110b Storage unit, 111, 111a, 111b Control information, 120 Monitoring unit, 130, 130a, 130b Control unit, 200 Optical mesh network, R1 Path, R2 Path, R3 Path, R4 Path, R5 Path, R6 Path, X1 Path, X2 Path, Y1 Path, Y2 Path, Z1 Reserved path, Z2 Reserved path.

Claims (7)

A control device that switches paths by controlling optical switches included in a plurality of nodes that construct an optical mesh network, the control device having a control unit that switches paths and assigns a plurality of wavelengths based on control information,
When a fault is detected in the optical mesh network, the control unit
The route on which the failure occurred is excluded from the route to be switched over.
When a route is switched back, wavelengths are assigned to prevent wavelength collisions.
The control information is to perform switching and wavelength allocation by giving priority to a route among a plurality of routes in the optical mesh network, the route being a route through which an optical signal in which a plurality of optical signals are multiplexed is communicated, or to perform switching of routes and wavelength allocation in descending order of the number of nodes included in the route after switching, and to perform wavelength allocation based on a First-Fit method, or to perform switching of routes and wavelength allocation in descending order of evaluation values calculated based on the number of nodes included in the route after switching and the bandwidth corresponding to the route after switching, and to perform wavelength allocation based on a First-Fit method.
Alternatively, the control unit may perform the following before a failure occurs in the optical mesh network:
When a route is switched back, wavelengths are assigned to prevent wavelength collisions.
The control information is to give priority to a route through which an optical signal in which a plurality of optical signals are multiplexed is communicated among a plurality of routes in the optical mesh network, and to set a reservation route for the route through which the multiplexed optical signal is communicated and a wavelength to be assigned to the reservation route.
Control device. A control device that switches paths by controlling optical switches included in a plurality of nodes that configure an optical mesh network, comprising:
A control unit that switches paths and assigns a plurality of wavelengths based on control information when a fault is detected in the optical mesh network.
having
The control unit is
The control information includes a first rule indicating that a route in which a fault has occurred is to be excluded from the route to which switching is to be performed, a second rule indicating that wavelengths are assigned so as to prevent wavelength collisions when a route is switched back, and a third rule indicating that switching and wavelength assignment are performed with priority given to a route through which an optical signal in which multiple optical signals are multiplexed is communicated, among a plurality of routes in the optical mesh network.
Control device. A control device that switches paths by controlling optical switches included in a plurality of nodes that configure an optical mesh network, comprising:
A control unit that switches paths and assigns a plurality of wavelengths based on control information when a fault is detected in the optical mesh network.
having
The control unit is
The control information includes a first rule indicating that a route in which a failure has occurred is to be excluded from a route to be switched over to, a second rule indicating that wavelengths are to be assigned so as to prevent wavelength collisions when a route is switched back, a third rule indicating that route switching and wavelength assignment are to be performed in descending order of the number of nodes included in the route after switching, and a fourth rule indicating that wavelengths are to be assigned based on a First-Fit method.
Control device. The control unit is
The control information further includes a fifth rule indicating that a route through which an optical signal in which a plurality of optical signals are multiplexed is communicated is given priority in switching and wavelength allocation among a plurality of routes in the optical mesh network;
the control information is a third rule indicating that after switching and wavelength allocation are performed with priority given to a route through which an optical signal in which a plurality of optical signals are multiplexed is communicated, route switching and wavelength allocation are performed in descending order of the number of nodes included in the route after switching;
The control device according to claim 1 or 3 . A control device that switches paths by controlling optical switches included in a plurality of nodes that configure an optical mesh network, comprising:
A control unit that switches paths and assigns a plurality of wavelengths based on control information when a fault is detected in the optical mesh network.
having
The control unit is
The control information includes a first rule indicating that a route in which a failure has occurred should be excluded from the route to which the switch is to be made, a second rule indicating that wavelengths should be allocated so as to prevent wavelength collisions when the route is switched back, a third rule indicating that route switching and wavelength allocation should be performed in descending order of evaluation values calculated based on the number of nodes included in the route after the switch and the bandwidth corresponding to the route after the switch, and a fourth rule indicating that wavelength allocation should be performed based on a First-Fit method.
Control device. A control device that switches paths by controlling optical switches included in a plurality of nodes that configure an optical mesh network, comprising:
a control unit that sets a reservation path to which a route is to be switched and a wavelength to be assigned to the reservation path based on control information before a failure occurs in the optical mesh network;
having
The control unit is
The control information includes a first rule indicating that, when a route is switched back, wavelengths are assigned so as to avoid wavelength collision, and a second rule indicating that, among a plurality of routes in the optical mesh network, a route through which an optical signal in which a plurality of optical signals are multiplexed is communicated is given priority, and the reservation route and the wavelength to be assigned to the reservation route are set for the route through which the multiplexed optical signal is communicated .
Control device. A program that causes a processor to function as the control device according to any one of claims 1 to 6.