JP5947752B2 - Network control system - Google Patents

Description

  The present invention relates to a network control system.

  It is important for network operators to effectively use the resources of the entire network to maintain transfer quality and reduce network costs. Network virtualization technology has been proposed as a technology for flexibly responding to sudden and irregular changes in the network due to future service diversification and realizing effective use of network resources.

  In the network virtualization technology, a logical virtual network is provided by logically dividing and combining various physical infrastructure network resources such as optical fibers, cross-connects, and routers as virtual resources. By changing the degree of division and combination according to changes in the environment such as the usage status of the physical infrastructure network and failures, it is possible to share physical resources (active resources and spare resources) between virtual networks, thus reducing the amount of resources. And improvement of network availability is expected. In order to realize such a sharing effect of physical resources, it is necessary to change the arrangement on the physical resources such as the function and performance of the virtual resources.

  In switching to the conventional shared spare resource, a spare configuration is first set in the switching destination node. An IF (Interface) for switching to a spare resource is prepared at the node serving as a switching end, a path is set, and the path is duplicated. After the update of the route information is completed, the route is switched by changing the configuration or the like, and the transfer of the virtual resource to the spare resource is completed (see, for example, Non-Patent Document 1). However, in this method, since it is necessary to always reserve a standby IF in the node at the switching end, the resource amount reduction effect due to sharing is reduced.

  In addition, as a related research, a method to relocate a software router that operates on a virtual machine (VM) has been proposed, but it is a method on a network that combines a server and a virtual machine, and its application area is limited. (For example, refer nonpatent literature 2). The technique of Non-Patent Literature 2 is implemented by a PC (Personal Computer) or the like, and performs switching to a spare resource in a software router, and does not perform switching to a spare resource on an actual router.

  In addition, assuming an IP (Internet Protocol) router that performs autonomous distributed control as a virtual resource, if the addresses included in the configuration are the same before and after the relocation, the routing protocol will not operate normally, so routing information exchange and state synchronization will not be possible. I can't. For this reason, it is necessary to create and verify a configuration for the reserve resource, which increases the operation cost. From the above, reduction of IF necessary for switching and reduction of operation cost related to configuration creation become issues.

Hereinafter, a conventional switching method to the shared spare resource will be described in detail with reference to FIGS. 13 and 14. A virtual router relocation method is taken as an example as a switching method to a shared spare resource.
FIG. 13 is a diagram for explaining a conventional virtual router relocation procedure. FIG. 14 is a flowchart showing a procedure for moving the virtual router of FIG. In the figure, S indicates each step of the flow.
In FIG. 13, as an example, it is assumed that the virtual router r2 of the node N2 is relocated to the virtual router r4 of the node N4 in a network composed of four nodes N1, N2, N3, and N4. Further, OSPF (Open Shortest Path First) is used as a network routing protocol.

The network control system includes a physical network (physical infrastructure network), a virtual network (IP layer) constructed on the physical network, and a network control device. The physical network includes a plurality of nodes N1 to N4 and physical links (here, optical fibers F1, F2, F3, and F4) that connect the nodes N1 to N4. Each of the nodes N1 to N4 includes physical routers (IP routers) R1 to R4 and optical cross connects OXC (Optical Cross Connect) 1 to 4 (optical transmission devices). In addition, each of the nodes N1 to N4 is connected to be able to communicate with the network control device.
Unless otherwise distinguished, the optical cross-connects OXC1 to OXC4 are expressed as an optical cross-connect OXC, the nodes N1 to N4 are expressed as a node N, and the optical fibers F1 to F4 are expressed as an optical fiber F.

  The components of the physical network and the virtual network are related to each other, and virtual routers r1 to r4 are arranged on physical routers (IP routers) R1 to R4 of the physical network. In FIG. 13, virtual routers r1 to r4 are represented in physical routers R1 to R4. In addition, optical paths having the virtual routers r1 to r4 as starting and ending points are set on the physical network, and the optical path forms a virtual link (IP link) in the virtual network.

The optical fiber F1 connects between the optical cross-connects OXC1 and OXC2, and the optical fiber F2 connects between the optical cross-connects OXC2 and OXC3. The optical fiber F3 connects between the optical cross connects OXC3 and OXC4, and the optical fiber F4 connects between the optical cross connects OXC4 and OXC1. The physical network has OXCs constituting the network and, for example, GMPLS (Generalized Multi-Protocol Label Switching) optical paths that pass between the OXCs.
The physical routers R1 to R4 have interfaces IF0 and IF1. The interface IF0 is an operational interface, and the interface IF1 is a standby interface. In addition, when not distinguishing interface IF0 and IF1, it describes with interface IF.

Next, a procedure for moving a virtual router in a conventional network control system will be described.
<Procedure 1>
As shown in FIG. 13A, a case where the virtual router r2 of the node N2 is moved to the virtual router r4 of the node N4 is taken as an example. In this case, the virtual router r2 of the node N2 is the relocation source virtual router, and the virtual router r4 of the node N4 is the relocation destination virtual router. When calculating a route from a certain starting node to other nodes, the link cost of the route with the lowest route cost (hereinafter referred to as “shortest route”) is indicated by a number surrounded by a circle in FIG. . For example, the link costs of the nodes N1 and N2, and the nodes N2 and N3 are “1”, respectively.

  First, in procedure 1, the basic configuration (IF, address, protocol, etc.), which is the basic setting for the relocation destination virtual router, is set in the relocation destination physical router R4 (step S1 in FIG. 14). Specifically, the network control device sets the basic configuration (IF, address, protocol, etc.) for the relocation destination virtual router r4 in the physical router R4 of the relocation destination node N4 with reference to the relocation source node N2. To do.

<Procedure 2>
As shown in FIG. 13B, in the procedure 2, the network control device moves between the switching end and the relocation destination virtual router between the node N1 and the node N4 and between the node N3 and the node N4. An optical path for connection is set (step S2 in FIG. 14). That is, an optical path is set in the nodes N1 and N3 serving as switching ends by using an interface IF1 prepared in advance for switching to a spare resource, and the path is duplexed.

<Procedure 3>
As shown in FIG. 13B, in step 3, the link cost is set so that the route of the relocation destination node N4 is not the shortest route (step S3 in FIG. 14). In step S4 of FIG. 14, the network control device determines whether or not the routing protocol has converged. When the routing protocol has converged, the process proceeds to step S5. Here, after setting the link cost (step S3 in FIG. 14), the routing protocol convergence determination is performed for the following reason. That is, the routing protocol convergence confirmation after setting the link cost is for determining whether or not the configuration can be changed in step S5 described later. If the routing protocol convergence is confirmed, the configuration change in step S5 described later is performed. Can be executed immediately. Note that a step of performing routing protocol convergence determination may be further added after the step S5 described later. In the case of FIG. 13, since “1” is set for the link cost of the optical path connecting the relocation source node N2 and the nodes N1, N3 at both ends thereof, the relocation destination node N3 and the nodes N1, N4 at both ends thereof are set. “2” is set to the link cost of the optical path connecting the two.

<Procedure 4>
As shown in FIG. 13C, in step 4, the configuration is changed so that the route of the relocation destination node N4 becomes the shortest route (step S5 in FIG. 14). Specifically, the network control device changes the configuration of the nodes N1, N2, and N3 so that the route of the relocation destination node N4 is the shortest route. Note that changing the configuration of each of the nodes N1 to N4 may affect the network, so only the configuration of the relocation source node N2 and the nodes N1 and N3 at both ends thereof is changed. It is preferable. Here, the link cost of the optical path connecting the relocation source node N2 and the nodes N1, N3 at both ends thereof is changed from “1” to “5”. As a result, the link cost of the optical path connecting the relocation destination node N4 and the nodes N1 and N3 at both ends thereof is “2”, and the link cost of the optical path connecting the relocation source node N2 and the nodes N1 and N3 at both ends thereof. Is set to “5”, and the optical path connecting the relocation-destination node N4, which is the shortest path viewed from the network path, and the nodes N1 and N3 at both ends thereof is selected.

<Procedure 5>
In step 5, as shown in FIG. 13D, the optical path is deleted. Further, unnecessary settings are deleted to complete the relocation (step S6 in FIG. 14).

Fortz B, Thorup M. Internet traffic engineering by optimizing OSPF weights. Proceedings of the INFO- COM’2000; 2000. p. 519-28. Wang, Yi ,; Keller, E .; Biskeborn, B .; Jacobus van der Merwe, Rexford, J .;, "Virtual routers on the move: live router migration as a networkmanagement primitive," SIGCOMM Comput. Commun. Rev. 38 , 4 (August 2008), 231-242.

  However, in the method of switching to the spare resource by changing the configuration after temporarily duplicating the route and exchanging the route information, as in the method of Non-Patent Document 1, the switching terminal is used to duplicate the route. The amount of resources increases because it is necessary to always reserve a spare IF in the node. In addition, since autonomous distributed control nodes (IP routers) require different configurations before and after switching, there is a problem that operational costs such as creation and verification of configurations increase.

  Thus, in the prior art, a standby interface must be secured at the switching end for switching from the active resource to the standby resource, and a configuration for switching to the standby resource is created. The increase in operation cost due to the need to verify the configuration is a problem.

  The present invention has been made in view of such a background, and the present invention eliminates the need for a standby system interface and a configuration for switching to a backup resource, and reduces the amount of resources and the operation cost. It is an object to provide a control system.

  In order to solve the above problems, the present invention provides a physical network composed of a physical router, an optical transmission device, and a physical link connecting them, and a virtual router disposed on the physical router, and the virtual router starts and ends The network control system includes a virtual network that configures a logical link and a network control device, and the transfer source virtual router is transferred to the transfer destination. The network control device is configured to transfer the transfer destination to the optical transmission device connected to the switching-end router that is a switching-end physical router from the transfer-source virtual router to the transfer-destination virtual router. Set the optical path to connect the virtual router, copy the transmission signal from the switching end router, and select the reception signal from the relocation source virtual router. A network information setting unit, wherein the optical transmission device sets the optical path to the relocation destination virtual router, replicates a signal from the switching end router, and transmits the signal to the relocation destination virtual router And a reception signal selection unit that selects a signal from the relocation destination virtual router as a reception signal after completion of state synchronization in which the same signal as that of the relocation source virtual router can be received by the relocation destination virtual router. And.

  By doing so, it is possible to reduce the spare IF by eliminating the need for switching at the router, and it is possible to switch to the spare resource without securing an IF for switching. Therefore, it is possible to reduce the resource amount and the operation cost.

  Further, the present invention provides the optical transmission apparatus in which the network control device copies the basic configuration for the virtual router set in the relocation source physical router to the relocation destination physical router and is connected to the switching end router. Sets a path to the relocation destination virtual router, prohibits signal reception from the relocation destination virtual router when replicating the signal from the switching end router and transmitting it to the relocation destination virtual router. The relocation destination virtual router can receive the same signal as the relocation source virtual router, and after completion of the state synchronization, the relocation is completed by selecting the signal from the relocation destination virtual router as the received signal. It is characterized by doing.

  By doing in this way, spare IF can be reduced and the operation cost regarding configuration creation can be reduced. Therefore, it is possible to reduce the resource amount and the operation cost.

  Further, the present invention resets the adjacency established in the relocation source virtual router in the state synchronization in which the physical router synchronizes route information between the relocation source virtual router and the relocation destination virtual router. When the routing protocol process is restarted in the virtual router before and after the relocation, the adjacency establishment is completed and the exchange of the routing information is completed, the received signal selection destination is changed to the relocation destination virtual router. An adjustment processing unit to be changed is provided.

  By doing so, it is possible to create route information by performing state synchronization between the relocation source and the relocation destination using the autonomous control of OSPF. In addition, since the process can be executed according to the existing protocol, it can be easily executed and can be applied universally. In addition, since only the route information related to itself is reflected in the relocation destination, unintended behavior can be eliminated in advance.

  In the state synchronization in which the physical router synchronizes path information between the relocation source virtual router and the relocation destination virtual router, the path information and protocol sequence possessed by the relocation source virtual router The memory information including the number, session information, adjacency or peer is duplicated, and processing is performed to input to the relocation destination virtual router. When the memory information has been input, the reception signal selection destination is set to the relocation destination The virtual router includes a memory information processing unit to be changed.

  In this way, the path information can be created by copying the path information of the transfer source virtual router to the transfer destination virtual router as it is and putting it in the transfer destination virtual router.

  According to the present invention, it is possible to provide a network control system that can reduce a resource amount and an operation cost by eliminating a configuration for switching to a standby IF and a backup resource necessary for switching.

It is a conceptual diagram explaining the virtual router moving method of the network control system which concerns on this embodiment. 1 is a configuration diagram of a network control system including a network control device according to the present embodiment. It is a functional block diagram which shows the structural example of the network control apparatus of the network control system which concerns on this embodiment. It is a functional block diagram which shows the structural example of the optical transmission apparatus of the network control system which concerns on this embodiment. It is a figure explaining the transfer procedure of the virtual router by the network control system of this embodiment. It is a flowchart which shows the transfer procedure of the virtual router of FIG. It is a functional block diagram which shows the structural example of the physical router applied to Example 1 of the network control system which concerns on this embodiment. It is a figure explaining the transfer procedure of the virtual router by Example 1 of the network control system which concerns on this embodiment. It is a flowchart which shows the transfer procedure of the virtual router of FIG. It is a functional block diagram which shows the structural example of the physical router applied to Example 2 of the network control system which concerns on this embodiment. It is a figure explaining the transfer procedure of the virtual router by Example 2 of the network control system which concerns on this embodiment. It is a flowchart which shows the transfer procedure of the virtual router of FIG. It is a figure explaining the virtual router transfer procedure of a prior art. It is a flowchart which shows the virtual router transfer procedure of FIG.

A network control system and the like in a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described below with reference to the drawings.
This is an example applied to a virtual router relocation method as a method for switching a virtual router to a shared spare resource in network virtualization.

(Overview)
FIG. 1 is a conceptual diagram illustrating a virtual router relocation method of a network control system according to an embodiment of the present invention. FIG. 1A shows a conventional virtual router relocation method, and FIG. 1B shows a virtual router relocation method of this embodiment. FIG. 1 (a) shows the node N1 side of the switching end of FIG. 13 (b).
In the conventional method for switching to a spare resource shown in FIG. 1A, a spare interface IF1 is prepared in advance separately from the active interface IF0 for switching to a spare resource. For this reason, the required amount of equipment has increased. In addition, it was necessary to create a dedicated configuration for the standby system.

On the other hand, the network control system according to the present embodiment shown in FIG. 1B employs the following virtual router relocation method (switching method to shared spare resources).
The network control apparatus 1 copies the basic configuration for the virtual router set in the relocation source physical router R2 to the relocation destination physical router R4 by a control system such as EMS (Element Management System). The network control device 1 connects an optical transmission device (such as OXC) 21 connected to a physical router (hereinafter referred to as a switching-end router) R1 serving as a switching end and a physical router R4 in which a relocation destination virtual router r4 is disposed. The path is set, the signal from the switching end router R1 is duplicated and transmitted to the relocation destination virtual router r4 (“signal duplication”). Here, since signals from the same IP address arrive at the relocation destination virtual router r4 and relocation source virtual router r2, appropriate routing cannot be performed. Therefore, the optical transmission device (such as OXC) 21 is configured not to receive a reception signal from the relocation destination virtual router r4 ("selection of reception signal"). As a result, the relocation-destination virtual router r4 can receive the same signal as that of the relocation-source virtual router r2, so that the states can be synchronized. After the completion of the state synchronization, the optical transmission device 21 completes the relocation by switching the received signal to be selected.

  By doing so, the network control system according to the present embodiment enables the reduction of the IF for switching to the standby system and the diversion of the configuration by performing signal duplication and reception signal selection in the optical transmission apparatus. , Equipment and operation costs can be reduced.

(Embodiment)
[Configuration of network control system]
FIG. 2 is a configuration diagram of the network control system 100 including the network control device 1 according to the present embodiment.
As shown in FIG. 2A, the network control system 100 includes a communication network 50 including a plurality of nodes 5 and links that provide communication paths by connecting the nodes 5, and each node 5 And a network control device 1 connected to be communicable with each other. The node 5 includes an IP router and an optical transmission device. A link connecting the nodes provides a communication path between the terminals.

  As shown in FIG. 2B, the network control system 100 includes a physical router (IP router), an optical transmission device (OXC), and a physical network including a physical link (transmission path) connecting them, and a physical router. A virtual router is disposed on the optical path, and an optical path having the virtual router as a start and end point is set on the physical network. The optical path is a virtual network that forms a logical link in the IP layer, and the network control device 1 . Note that the network control device 1 obtains traffic-related information from each node 5, a network management device (not shown), and the like. Then, the network control device 1, for example, when a resource such as a node 5 or a link fails and a path that does not pass through the failed resource is reset, the setting order of a path to be newly set, information on the acquired traffic, and the like Determine based on.

In the network control system 100, a wavelength path is set on the physical network of the communication network 50 (for example, a WDM (Wavelength Division Multiplexing) network) under the control of the network control device 1. The physical network includes an IP router (physical), an optical transmission device, and a physical link that connects them. A virtual router is arranged on the physical router, and an optical path starting from the virtual router is set on the physical network, and the optical path forms a logical link in the IP layer. The optical transmission device is, for example, OXC. The physical link is, for example, an optical fiber.
In addition, although the wavelength path is accommodated in the physical network of the communication network 50, it is applicable not only to a wavelength path but to arbitrary path networks, such as a GMPLS path.

FIG. 3 is a functional block diagram illustrating a configuration example of the network control device 1 of the network control system according to the present embodiment.
[Network control device 1]
As illustrated in FIG. 3, the network control device 1 includes a control unit 10, an input / output unit 12, a memory unit 13, and a storage unit 14.
The control unit 10 controls the entire network control device 1 and includes a network information setting unit 11. For example, the control unit 10 is realized by a CPU (Central Processing Unit) developing and executing a program (network control program) stored in the storage unit 14 in a RAM (Random Access Memory) that is the memory unit 13.

  The network information setting unit 11 inputs a command, a configuration, etc. to the IP router. The network information setting unit 11 copies the basic configuration for the virtual router set in the relocation source physical router to the relocation destination physical router. The network information setting unit 11 sets the optical path for connecting the relocation destination virtual router to the optical transmission apparatus 20 (see FIG. 4), duplication of the transmission signal from the switching end router, and the relocation source virtual. Set the selection of the received signal from the router.

The input / output unit 12 includes a communication interface that transmits and receives information via a communication line, and an input / output interface that inputs and outputs information between an input unit such as a keyboard (not shown) and an output unit such as a monitor. Composed.
The memory unit (storage unit) 13 includes a primary storage unit such as a RAM, and temporarily stores information necessary for data processing by the control unit 10.
The storage unit (storage unit) 14 includes a storage unit such as a hard disk or a flash memory.
A plurality of devices having the same function as the network control device 1 may be installed for each type of the node 5 to be controlled and the number of nodes.

FIG. 4 is a functional block diagram illustrating a configuration example of the optical transmission device 20 of the network control system according to the present embodiment.
[Optical transmission device 20]
The optical transmission device 20 is optical transmission equipment, and is a device that transmits information or transmits data using light, such as OXC. Hereinafter, the optical transmission apparatus 20 is referred to as OXC20. The OXC 20 constituting each node is represented as OXC21, OXC22, OXC23, OXC24 as described later.

The OXC (optical transmission apparatus) 20 includes a control unit 30 that controls the entire OXC 20, and an OXC function unit 40 that performs electrical signal / optical signal conversion, signal relaying, branching, and division. The control unit 30 includes a signal duplicating unit 31 and a received signal selecting unit 32.
The signal duplicating unit 31 sets a path to the relocation destination virtual router, duplicates the signal from the switching end router, and transmits it to the relocation destination virtual router.
The received signal selection unit 32 synchronizes the state of path information that enables the relocation destination virtual router to receive the same signal as that of the relocation source virtual router, and after completion of the state synchronization, the signal from the relocation destination virtual router Is selected as the received signal.
The OXC 20 is configured by adding a signal duplication unit 31 and a reception signal selection unit 32 to the conventional OXC.

Hereinafter, a virtual router relocation method of the network control system configured as described above will be described.
FIG. 5 is a diagram for explaining the relocation procedure of the virtual router by the network control system according to the present embodiment.
In the following, it is assumed that a virtual router r2 arranged at the node N2 is moved to a virtual router r4 arranged at the node N4 in a network composed of four nodes N1, N2, N3, N4 as an example. Further, OSPF is used as a network routing protocol.

The network control system 100 includes a physical network, a virtual network (IP layer) constructed on the physical network, and the network control device 1.
As shown in FIG. 5, the physical network includes a plurality of nodes N1 to N4 and physical links (here, optical fibers F1, F2, F3, and F4) that connect the nodes N1 to N4. Each of the nodes N1 to N4 includes physical routers (IP routers) R1 to R4 and OXCs 21 to 24 (20) (optical transmission devices). Further, each of the nodes N1 to N4 is connected to the network control device 1 so as to be communicable.

  Unless otherwise distinguished, OXC21 to OXC24 are denoted as OXC20 (see FIG. 4), nodes N1 to N4 are denoted as node N, and optical fibers F1 to F4 are denoted as optical fiber F.

  The components of the physical network and the virtual network are related to each other, and virtual routers r1 to r4 are arranged on physical routers (IP routers) R1 to R4 of the physical network. In FIG. 5, virtual routers r1 to r4 are represented in physical routers R1 to R4. In addition, optical paths having the virtual routers r1 to r4 as starting and ending points are set on the physical network, and the optical path forms a virtual link (IP link) in the virtual network.

  The optical fiber F1 connects between OXC21 and OXC22, and the optical fiber F2 connects between OXC22 and OXC23. The optical fiber F3 connects between the OXC 23 and OXC 24, and the optical fiber F4 connects between the OXC 24 and OXC 21.

The OXCs 21 and 23 connected to the switching end router set the path to the relocation destination virtual router, replicate the signal from the relocation destination router, and transmit it to the relocation destination virtual router. By prohibiting the reception of this signal, the destination virtual router synchronizes the state of the route information that makes it possible to receive the same signal as the source virtual router, and after the state synchronization is completed, the virtual router from the destination virtual router The relocation is completed by selecting the signal as the received signal.
The physical routers R1 and R3 have one interface IF, and the physical routers R2 and R4 have two interfaces IF0 and IF1 (IF). In this embodiment, the interfaces IF0 and IF1 are both operational interfaces. In addition, when not distinguishing interface IF0 and IF1, it describes with interface IF.

[Relocation procedure of virtual router]
Next, a procedure for moving a virtual router in the network control system of this embodiment will be described.
In the relocation procedure of the network control system of the present embodiment in FIG. 5, the flow of transmission signals between routers is indicated by arrows, and the state in which a reception signal is not selected by a switching end router is indicated by x.

Here, a case where the virtual router r2 arranged at the node N2 is moved to the virtual router r4 arranged at the node N4 is taken as an example. In this case, the physical routers R1 and R3 of the nodes N1 and N3 at both ends of the node N2 are switching end routers. The virtual router r2 of the node N2 and the switching end routers of the nodes N1 and N3 at both ends thereof are set with an optical path for connecting the node N2 and the nodes N1 and N3 at both ends thereof via the interface IF. Yes.
As indicated by arrows a and b in FIG. 5A, signals between routers flow from the migration source virtual router r2 to the switching end router, and from the switching end router to the migration source virtual router r2.

<Procedure 1>
In procedure 1, the basic configuration (IF, address, protocol, etc.) for the transfer source virtual router is set in the transfer destination physical router R4.
Specifically, the network information setting unit 11 of the network control device 1 refers to the physical router R2 of the relocation source and sets the basic configuration (IF, address, protocol, etc.) for the relocation source virtual router r2 to the relocation destination. Set in the physical router R4 of the node N4. That is, the network information setting unit 11 of the network control device 1 copies the configuration for the virtual router r2 set in the relocation source physical router R2, and inputs the same configuration to the relocation destination physical router R4. Incidentally, the introduction of the same configuration to the relocation destination physical router R4 was performed for the first time in the present embodiment and could not be realized by the conventional technology. In other words, in the prior art, the same configuration cannot be input to the relocation destination physical router R4, so it has been necessary to change the IP address, for example. In this case, since different configurations are required before and after switching, operation costs such as configuration creation and verification increase.

<Procedure 2>
After setting in procedure 1, the procedure proceeds to procedure 2.
As shown in FIG. 5B, in the procedure 2, the network control device 1 sets an optical path for connecting the OXC 21 and OXC 23 that are the optical transmission devices at the switching end and the virtual router r4 that is the transfer destination. Specifically, the network information setting unit 11 of the network control device 1 connects the OXC 21 and OXC 23 (switching end optical transmission device) connected to the switching end router and the physical router R4 in which the destination virtual router r4 is arranged. A path to be transferred is set, and an optical path is set to the relocation destination virtual router r4. In step 1 above, the configuration for the relocation source virtual router r2 is copied and the same configuration is input to the relocation destination physical router R4. Therefore, the optical path is set so that the topology of the IP layer does not change before and after relocation. can do.

<Procedure 3>
As shown in FIG. 5 (b), in the procedure 3, the network information setting unit 11 of the network control device 1 switches the switching end router with respect to OXC21 and OXC23 (switching end optical transmission device) connected to the switching end router. Is set so that the relocation source signal is selected as the received signal, and the optical path transmission setting to the relocation destination virtual router r4.
With this setting, the OXC 21 and OXC 23 at the switching end duplicate the transmission signal of the switching end router and transmit it to the virtual router r4 at the relocation destination. Specifically, the signal duplication unit 31 (see FIG. 4) of the OXC 21 and OXC 23 at the switching end duplicates the transmission signal from the switching end router.

  Here, transmission signal duplication will be described. As a basic idea, as shown in FIG. 5B, all transmission signals superimposed on the optical path are duplicated. This transmission signal duplication is started, for example, from the time when the configuration for the virtual router is copied in the procedure 1 until the state synchronization in the procedure 4 described later is completed.

  A signal flow between routers in step 3 will be described. As the transmission signal of the switching end router is duplicated in the switching end OXC21 and OXC23, the signal flow is changed from the switching end router to the source virtual router as indicated by arrows b and c in FIG. It is divided and output in two directions, r2 and the relocation destination virtual router r4. At this time, as indicated by an arrow d in FIG. 5B, the OXC 21 and OXC 23 at the switching end do not receive the reception signal from the relocation destination virtual router r4 by the selection of the reception signal.

  Thereby, since the same signal is received by the virtual routers before and after the relocation, the information between the routers is synchronized. Further, by not receiving a signal from the relocation destination virtual router r4, even if the same configuration is used, the operation can be performed without affecting the autonomous distributed control. In other words, since the signal from the relocation destination virtual router r4 is not received, the relocation destination virtual router r4 is not visible (not recognized) when viewed from the entire network. For example, even if the same IP address exists, autonomous distributed control is not affected.

<Procedure 4>
As shown in FIG. 5C, in the procedure 4, after the completion of the state synchronization, the OXC 21 and the OXC 23 (switching end optical transmission device) select a signal from the relocation destination virtual router r4 as a received signal. Here, the state synchronization means synchronizing the path information between the relocation source virtual router r2 and the relocation destination virtual router r4. Details of the state synchronization will be described later with reference to FIGS.

  The flow of signals between routers in procedure 4 will be described. As indicated by an arrow d in FIG. 5C, the OXC 21 and OXC 23 at the switching end receive the received signal from the relocation destination virtual router r4 by selecting the received signal after completion of the state synchronization, while FIG. As indicated by the arrow a in c), the reception signal from the relocation source virtual router r2 is not received. That is, in the initial state (procedures 1 to 3), the signal from the relocation source virtual router r2 is received. However, by copying the signal, the relocation source virtual router r2 and the relocation destination virtual router Since the signal arrives from two locations with r4, the reception signal from the relocation destination virtual router r4 is not first received by selecting the reception signal (see arrow d in FIG. 5B), and the state After the synchronization is completed, the reception signal from the relocation source virtual router r2 is not received (see arrow a in FIG. 5C), and finally the signal of the relocation destination virtual router r4 is received (see FIG. 5C). (See arrow d in FIG. 5 (d)).

<Procedure 5>
As shown in FIG. 5D, in step 5, the network information setting unit 11 of the network control device 1 deletes the optical path for connecting the relocation source virtual router r2 and the switching ends OXC21 and OXC23.

<Procedure 6>
As shown in FIG. 5D, in step 6, the network information setting unit 11 of the network control device 1 deletes the unnecessary configuration from the transfer source, thereby completing the transfer. Here, the unnecessary configuration at the relocation source is a configuration for the copy source virtual router when the configuration for the virtual router is first copied. In FIG. 5D, the virtual router r2 represented in the physical router R2 has been deleted to indicate that the relocation source virtual router r2 has been relocated to the relocation destination virtual router r4. .

FIG. 6 is a flowchart showing the relocation procedure of the virtual router of FIG. In the figure, S indicates each step of the flow.
When the transfer is started, in step S11, the network information setting unit 11 (FIG. 3) of the network control device 1 sets a basic configuration (IF, address, protocol, etc.) in the transfer destination physical router (physical resource). That is, the basic configuration (IF, address, protocol, etc.) for the relocation source virtual router is set in the relocation destination physical router R4 (see procedure 1 in FIG. 5).

In step S12, the network information setting unit 11 sets an optical path for connecting the OXC 21 and OXC 23 (switching-end optical transmission device) connected to the switching-end router and the relocation destination virtual router r4 (procedure 2 in FIG. 5). reference).
In step S13, the network information setting unit 11 sets the duplication of the transmission signal from the switching end router and the selection of the received signal in the OXC 21 and OXC 23 at the switching end.

In step S14, the OXC 21 and OXC 23 at the switching end wait until the state synchronization is completed (see procedure 4 in FIG. 5) (S14: No).
When the state synchronization is completed (S14: Yes), in step S15, the switching end OXC21 and OXC23 (switching end optical transmission apparatus) select a signal from the relocation destination virtual router r4 as a received signal.
In step S16, the network information setting unit 11 deletes the optical path for connecting the relocation source virtual router and the OXC 21 and OXC 23 at the switching end (see procedure 5 in FIG. 5).
In step S17, the network information setting unit 11 deletes the unnecessary setting of the physical resource before the transfer and ends this flow (transfer is completed) (see procedure 6 in FIG. 5).

  As described above, in this embodiment, in the network control system 100 including the IP router and the OXC 20 (optical transmission apparatus), the received signal is selected by the OXC 20 and the signal is duplicated. By selecting the received signal with the OXC 20, it is possible to use the same configuration in the virtual router before and after the relocation. Further, by duplicating the transmission signal at the OXC 20 and transmitting the same signal from one interface to the virtual routers before and after the relocation, it is possible to reduce the interfaces required at the switching end router. A network control system 100 that performs autonomous distributed control by duplicating signals and selecting received signals in the OXC 20 can be constructed.

[Elemental technology]
Next, elemental technology in the present invention will be described. Here, a state synchronization method is provided in which path information between the relocation source virtual router and the relocation destination virtual router is synchronized. It is a specific example of the state synchronization in step S14 of FIG.
In the present embodiment, the OXC 20 (optical transmission apparatus) duplicates the transmission signal from the switching end router and selects the reception signal, thereby enabling simultaneous operation of virtual routers having the same IP address. In addition, by transmitting one signal to the virtual routers before and after the relocation, the routing information between the routers can be synchronized.

An embodiment when synchronizing the route information will be described below.
The procedures from the configuration input to the relocation destination physical router described in the relocation procedure of FIGS. 5 and 6 to the duplication of the transmission signal and the selection of the reception signal are the same in each embodiment.

Example 1
The first embodiment is a method of synchronizing route information by reconstructing an adjacency relationship.
FIG. 7 is a functional block diagram showing a configuration example of a physical router applied to Example 1 of the network control system according to the present embodiment. The physical router 60 of the first embodiment can be applied to the physical router (IP router) of the network control system 100 shown in FIG.
As shown in FIG. 7, the physical router 60 includes a path information synchronization unit 70 and a router function unit 80. The route information synchronization unit 70 includes an adequacy processing unit 71. In the case of OSPF, the adjacency represents an adjacency relationship with which router it is connected to.
The route information synchronization unit 70 synchronizes route information with another node by receiving a link state notification from another node and transferring it to an adjacent node according to a processing procedure defined by OSPF.

  The adequacy processing unit 71 executes state synchronization processing that synchronizes path information between the transfer-source virtual router and the transfer-destination virtual router according to the settings of the network control device 1 (FIG. 2). Specifically, the adequacy processing unit 71 (1) resets the adjacency established in the relocation source virtual router, and restarts the routing protocol process in the virtual router before and after the relocation, (2) adjacency establishment (3) When the establishment of adjacency is completed and the exchange of path information is completed, the reception signal selection destination is changed to the switching destination router.

FIG. 8 is a diagram for explaining the relocation procedure of the virtual router according to Example 1 of the network control system according to the present embodiment. The same components and elements as those in FIG. FIG. 9 is a flowchart showing the relocation procedure of the virtual router of FIG. In addition, it demonstrates fundamentally using FIG. 8, and demonstrates suitably with reference to FIG.
As described above, state synchronization refers to synchronizing path information between the relocation source virtual router r2 and the relocation destination virtual router r4. Here, the case of OSPF is taken as an example, but other protocols such as BGP (Border Gateway Protocol) may be used.

<Procedure 1>
As shown in FIG. 8A, in step 1, the basic configuration (IF, address, protocol, etc.) for the migration source virtual router r2 is set in the migration destination physical router R4 (physical resource). Specifically, in step S11 of FIG. 9, the network information setting unit 11 of the network control device 1 refers to the physical router R2 that is the migration source, and the basic configuration (IF, address, Protocol, etc.) is set in the physical router R4 of the relocation destination node N4. As a result, the same configuration as the configuration for the virtual router set in the relocation source physical router R2 is input to the relocation destination physical router R4.

<Procedure 2>
As shown in FIG. 8B, in the procedure 2, the network control device 1 sets an optical path for connecting the OXC 21 and OXC 23 that are the optical transmission devices at the switching end and the virtual router r4 that is the transfer destination. Specifically, the network information setting unit 11 of the network control device 1 connects the OXC 21 and OXC 23 (switching end optical transmission device) connected to the switching end router and the physical router R4 in which the destination virtual router r4 is arranged. And sets an optical path to the relocation destination virtual router r4 (step S12 in FIG. 9). In step 1 above, the configuration for the relocation source virtual router r2 is copied and the same configuration is input to the relocation destination physical router R4. Therefore, the optical path is set so that the topology of the IP layer does not change before and after relocation. can do.

<Procedure 3>
Next, as shown in FIG. 8B, in step 3, the network information setting unit 11 of the network control device 1 switches between OXC21 and OXC23 (switching end optical transmission device) connected to the switching end router. A setting is made such that the transmission signal from the end router is copied, the transmission setting of the optical path to the relocation destination virtual router r4, and the relocation source signal is selected as the reception signal.
The network information setting unit 11 sets the duplication of the transmission signal from the switching end router and the selection of the reception signal (step S13 in FIG. 9).

  With this setting, the OXC 21 and OXC 23 at the switching end duplicate the transmission signal from the switching end router and transmit it to the relocation destination virtual router r4. Specifically, the signal duplication unit 31 (see FIG. 4) of the OXC 21 and OXC 23 at the switching end duplicates the transmission signal from the switching end router.

  A signal flow between routers in step 3 will be described. As a result of duplication of the transmission signal of the switching end router at the switching end OXC21 and OXC23, as shown by arrows b and c in FIG. 8 (b), the signal flow changes from the switching end router to the source virtual router. It is divided and output in two directions, r2 and the relocation destination virtual router r4. At this time, as indicated by an arrow d in FIG. 8B, the OXC 21 and OXC 23 at the switching end do not receive the received signal from the relocation destination virtual router r4 by selecting the received signal.

  Thereby, since the virtual routers before and after the relocation receive the same signal, the information between the routers is synchronized. Further, by not receiving a signal from the relocation destination virtual router r4, even if the same configuration is used, the operation can be performed without affecting the autonomous distributed control. In other words, since the signal from the relocation destination virtual router is not received, the relocation destination virtual router r4 is invisible (not recognized) when viewed from the entire network. For example, even if the same IP address exists, autonomous distributed control is not affected.

<Procedure 4>
As shown by reference signs e and f in FIG. 8C, in step 4, the adjacency processing unit 71 (FIG. 7) of the physical routers R2 and R4 is adjusted to the adjacency (OSPF) established in the relocation source virtual router r2. In this case, it represents an adjacent relationship with which router it is connected to) and restarts the routing protocol process simultaneously on the virtual routers before and after the relocation (step S21 in FIG. 9). When the adequacy processing unit 71 of the physical routers R2 and R4 resets the adjacency, the OSPF protocol rebuilds the adjacency relationship with itself from scratch. If the configuration has not been changed, the adjacency description will be the same before and after resetting the adjacency.

  In this embodiment, the adequacy processing unit 71 resets this adequacy, restarts the routing protocol process, and constructs the same state in the relocation source virtual router r2 and the relocation destination virtual router r4. In OSPF, packet exchange is not basically performed when adjacency is established. Therefore, by performing the reset and restarting of the routing protocol process, the relocation source virtual router r2 and the relocation destination virtual router in the process. The same state is constructed with r4 (that is, route information is sent to the relocation destination virtual router r4). Note that by performing the adjacency reset and the restart at the same time in the virtual router before and after the relocation, the packet for exchanging the route information is received at an unintended timing, and the route information of the relocation destination virtual router is This prevents it from changing from a virtual router.

Next, the control unit 30 (see FIG. 4) of the OXC 20 performs packet exchange for establishing adjacency. At this time, the same IP address and interface IF settings are used before and after the relocation. For this reason, the relocation destination virtual router r4 receives the packet addressed to the relocation source virtual router r2 as a packet addressed to itself and can establish adjacency.
In step S22 of FIG. 9, the control unit 30 of the OXC 20 (optical transmission apparatus) waits until the routing protocol converges.
As soon as the establishment of the adequacy is completed and the exchange of the path information is completed, the selection destination of the received signal is changed to the switching destination router by the OXC 21 and OXC 23 at the switching end.

<Procedure 5>
As shown in FIG. 8D, in step 5, after convergence of the routing protocol (step S22 in FIG. 9: Yes), the OXC 21 and OXC 23 at the switching end (switching end optical transmission device) are moved from the relocation destination virtual router. Is selected as a received signal (step S22 in FIG. 9: Yes).

<Procedure 6>
As shown in FIG. 8D, in step 6, the network information setting unit 11 of the network control device 1 connects the relocation source virtual router r2 and the switching end OXC21, OXC23 (switching end optical transmission device). The optical path is deleted (step S16 in FIG. 9).

<Procedure 7>
As shown in FIG. 8D, in step 7, the network information setting unit 11 deletes the unnecessary configuration (configuration for the copy source virtual router) of the transfer source to complete the transfer (in FIG. 9). Step S17).

  In the first embodiment, each node included in the network control system 100 includes an adjuster processing unit 71. The adjuster processor 71 uses the autonomous control of OSPF to determine the status of the transfer-source virtual router and the transfer-destination virtual router. It is possible to create route information by performing synchronization. In addition, since the process can be executed according to the existing protocol, it can be easily executed and can be applied universally. In addition, since only the route information related to itself is reflected in the relocation destination, unintended behavior can be eliminated in advance.

(Example 2)
The second embodiment is a synchronization method by copying memory information.
FIG. 10 is a functional block diagram illustrating a configuration example of a physical router applied to Example 2 of the network control system according to the present embodiment. The same components as those in FIG. 7 are denoted by the same reference numerals. The physical router 60A of the second embodiment can be applied to the physical router (IP router) of the network control system 100 shown in FIG.

As shown in FIG. 10, the physical router 60 </ b> A includes a path information synchronization unit 70 </ b> A and a router function unit 80. The path information synchronization unit 70A includes a memory information processing unit 72.
The route information synchronization unit 70A synchronizes route information with another node by receiving a link state notification from another node and transferring it to an adjacent node in accordance with a processing procedure defined in OSPF.

  The memory information processing unit 72 executes state synchronization processing by managing memory information according to the settings of the network control device 1 (FIG. 2). Specifically, the memory information processing unit 72 (1) Memory information that is not included in the original configuration and includes path information, protocol sequence number, session information, adjacency or peer, which the relocation source virtual router r2 has. Is copied to the relocation destination virtual router r4. (2) When the input of the memory information is completed, the reception signal selection destination is changed to the switching destination router.

  FIG. 11 is a diagram for explaining the relocation procedure of the virtual router according to Example 2 of the network control system according to the present embodiment. The same components and elements as those in FIG. FIG. 12 is a flowchart showing the relocation procedure of the virtual router of FIG. In addition, it demonstrates fundamentally using FIG. 11, and demonstrates with reference to FIG. 12 suitably.

<Procedure 1>
As shown in FIG. 11A, in the procedure 1, the basic configuration (IF, address, protocol, etc.) for the migration source virtual router r2 is set in the migration destination physical router R4 (physical resource). Specifically, in step S11 of FIG. 12, the network information setting unit 11 of the network control device 1 refers to the node N2 that is the transfer source, and the basic configuration (IF, address, protocol for the transfer source virtual router r2). Etc.) is set in the physical router R4 arranged in the transfer destination node N4. As a result, the same configuration as the configuration for the virtual router set in the relocation source physical router R2 is input to the relocation destination physical router.

<Procedure 2>
As shown in FIG. 11B, in the procedure 2, the network control apparatus 1 sets an optical path for connecting the OXC 21 and OXC 23 which are the optical transmission apparatuses at the switching end and the virtual router r4 as the transfer destination. Specifically, in step S12 of FIG. 12, the network information setting unit 11 of the network control device 1 arranges the OXC 21 and OXC 23 (switching end optical transmission device) connected to the switching end router and the relocation destination virtual router r4. A path for connecting to the physical router R4 is set, and an optical path is set to the relocation destination virtual router r4. In step 1 above, the configuration for the relocation source virtual router r2 is copied and the same configuration is input to the relocation destination physical router R4. Therefore, the optical path is set so that the topology of the IP layer does not change before and after relocation. can do.

<Procedure 3>
In the network information setting unit 11, the OXC 21 and OXC 23 at the switching end set the copy of the transmission signal from the switching end router and the selection of the received signal (step S 13 in FIG. 12).
Next, as shown in FIG. 11B, in step 3, the network information setting unit 11 of the network control device 1 switches the OXC 21 and OXC 23 (switching end optical transmission device) connected to the switching end router. A setting is made such that the transmission signal from the end router is copied, the transmission setting of the optical path to the relocation destination virtual router r4, and the relocation source signal is selected as the reception signal.

  With this setting, the OXC 21 and OXC 23 at the switching end duplicate the transmission signal from the switching end router and transmit it to the relocation destination virtual router. Specifically, the signal duplication unit 31 (see FIG. 4) of the OXC 21 and OXC 23 at the switching end duplicates the transmission signal from the switching end router.

  A signal flow between routers in step 3 will be described. As the transmission signal of the switching end router is duplicated in the switching end OXC 21 and OXC 23, the signal flow is changed from the switching end router to the relocation source virtual router as shown by arrows b and c in FIG. It is divided and output in two directions, r2 and the relocation destination virtual router r4. At this time, as indicated by an arrow d in FIG. 11B, the OXC 21 and OXC 23 at the switching end do not receive the received signal from the relocation destination virtual router r4 by selecting the received signal.

<Procedure 4>
As shown by reference sign g and reference sign h in FIG. 11C, in step 4, the memory information processing unit 72 of the path information synchronization unit 70A of the physical router 60A is not included in the original configuration, and the relocation source virtual router The information (memory information) on the memory such as path information, protocol sequence number, session information, adequacy (in the case of OSPF), peer (in the case of BGP), etc. that r2 has is copied and transferred to the destination virtual router r4. (Step S31 in FIG. 12). Here, in the procedure 1 (step S11 in FIG. 12), for the configuration not including the memory information, the same configuration as the configuration for the virtual router set in the physical router R2 that is the transfer source is the transfer destination physical router. R4 is used. The input of the memory information is, for example, a configuration copy to the relocation destination virtual router r4.
Next, the control unit 30 of the OXC 20 changes the reception signal selection destination to the switching destination virtual router r4 as soon as the input of the memory information is completed.

<Procedure 5>
As shown in FIG. 11C, in step 5, after the memory information is copied, the OXC 21 and OXC 23 (switching end optical transmission device) at the switching end select a signal from the relocation destination virtual router r4 as the received signal. (Step S15 in FIG. 12).

<Procedure 6>
As shown in FIG. 11D, in step 6, the network information setting unit 11 of the network control device 1 connects the relocation source virtual router r2 and the switching end OXC21 and OXC23 (switching end optical transmission device). The optical path is deleted (step S16 in FIG. 12).

<Procedure 7>
As shown in FIG. 11D, in step 7, the network information setting unit 11 deletes the unnecessary configuration (configuration for the copy source virtual router) of the transfer source to complete the transfer (in FIG. 12). Step S17).

  In the second embodiment, each node constituting the network control system 100 includes a memory information processing unit 72. The memory information processing unit 72 duplicates the route information of the transfer source virtual router as it is to the transfer destination, and transfers it to the transfer destination. By inputting, route information can be created. In this case, it is assumed that the physical router includes a memory information processing unit 72, that is, a memory information duplication function is implemented. In the second embodiment, since the route information of the relocation destination virtual router is completely replaced with the route information of the relocation source virtual router, the route information created by the relocation destination virtual router is lost.

  As described above, in the network control system 100, the network control device 1 copies the basic configuration for the virtual router set in the relocation source physical router R2 to the relocation destination physical router R4, and at the same time, the OXC (optical Network for setting the optical path connecting the relocation destination virtual router r4, the duplication of the transmission signal from the switching end router, and the selection of the received signal from the relocation source virtual router r2 An information setting unit 11 is provided. The OXC 20 includes a signal duplicating unit 31 in which the control unit 30 sets a path to the relocation destination virtual router r4, duplicates a signal from the switching end router, and transmits the signal to the relocation destination virtual router r4. The virtual router r4 performs state synchronization so that the same signal as that of the relocation source virtual router r2 can be received, and after completion of the state synchronization, a signal from the relocation destination virtual router r4 is selected as a reception signal. Part 32.

  In the virtual router relocation method of the network control system 100, the network control device 1 copies the basic configuration for the virtual router set in the relocation source physical router R2 to the relocation destination physical router R4. The network control device 1 sets a path for connecting the OXCs 21 and 23 connected to the switching-end router and the physical router R4 in which the transfer-destination virtual router r4 is arranged, and copies the signal from the switching-end router to Transmit to the virtual router r4. At this time, the signal from the relocation destination virtual router r4 is not received. As a result, the relocation-destination virtual router r4 can receive the same signal as that of the relocation-source virtual router r2, so that the states can be synchronized. After the state synchronization is completed, the relocation is completed by switching the reception signal selected by the optical transmission apparatus.

  By doing so, the network control system 100 can reduce the IF for switching to the standby system and divert the configuration by performing signal duplication / selection of the received signal in the OXC 20, and resources by sharing the spare resource It is possible to reduce the amount and cost of facilities and operations.

  Each of the above-described configurations, functions, processing units, processing means, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Further, each of the above-described configurations, functions, and the like may be realized by software for interpreting and executing a program that realizes each function by the processor. Information such as programs, tables, and files for realizing each function is stored in a memory, a hard disk, a recording device such as an SSD (Solid State Drive), an IC (Integrated Circuit) card, an SD (Secure Digital) card, an optical disk, etc. It can be held on a recording medium. Further, in this specification, the processing steps describing time-series processing are not limited to processing performed in time series according to the described order, but are not necessarily performed in time series, either in parallel or individually. The processing (for example, parallel processing or object processing) is also included.

DESCRIPTION OF SYMBOLS 1 Network control apparatus 5 Node 10, 30 Control part 11 Network information setting part 20-24 OXC (optical transmission apparatus)
31 Signal Duplicating Unit 32 Received Signal Selecting Unit 50 Communication Network 60, 60A Physical Router 70, 70A Route Information Synchronizing Unit 71 Adjacency Processing Unit 72 Memory Information Processing Unit 80 Router Functional Unit 100 Network Control System

Claims (4)

A physical network composed of a physical router, an optical transmission device, and a physical link connecting them, a virtual router is arranged on the physical router, and an optical path with the virtual router as a start / end point is set on the physical network A network control system comprising a virtual network constituting a logical link and a network control device, and relocating a relocation source virtual router to a relocation destination,
The network controller is
A setting of an optical path that connects the relocation destination virtual router to the optical transmission device connected to the switching end router that is a physical router at the relocation destination from the relocation source virtual router to the relocation destination virtual router; A copy of the transmission signal from the switching end router, and a network information setting unit for setting the selection of the reception signal from the relocation source virtual router,
The optical transmission device is:
A signal duplicating unit that sets the optical path to the relocation destination virtual router, replicates a signal from the switching end router, and transmits the signal to the relocation destination virtual router;
A reception signal selection unit that selects a signal from the relocation destination virtual router as a reception signal after completion of state synchronization that enables reception of the same signal as the relocation source virtual router at the relocation destination virtual router;
A network control system comprising: The network controller is
Copy the basic configuration for the virtual router set in the physical router of the transfer source to the physical router of the transfer destination,
The optical transmission device connected to the switching end router is:
By setting a path to the relocation destination virtual router, and copying the signal from the switching end router and transmitting it to the relocation destination virtual router, by prohibiting signal reception from the relocation destination virtual router, The relocation destination virtual router can receive the same signal as that of the relocation source virtual router. After completion of the state synchronization, the relocation is completed by selecting a signal from the relocation destination virtual router as a received signal. The network control system according to claim 1. The physical router is
In the state synchronization for synchronizing the route information between the relocation source virtual router and the relocation destination virtual router,
Reset the adjacency established in the relocation source virtual router, and restart the routing protocol process in the virtual router before and after relocation,
The adjacency processing part which changes the selection destination of a received signal into the virtual router of the relocation destination when establishment of the adjacency is completed and exchange of route information is completed is provided. Network control system. The physical router is
In the state synchronization for synchronizing the route information between the relocation source virtual router and the relocation destination virtual router,
Copy the memory information including the route information, protocol sequence number, session information, adjacency or peer that the relocation source virtual router has, and perform the process of entering the relocation destination virtual router,
The network control system according to claim 1, further comprising a memory information processing unit that changes a selection destination of a received signal to the relocation destination virtual router when the input of the memory information is completed.

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