JP6043307B2 - Network controller - Google Patents

Description

  The present invention relates to a technique for switching a current router to a spare router.

  Network operators effectively use the resources of the entire network to maintain the quality of information transfer and promote measures to reduce network costs by reducing unnecessary resources. To achieve this, network virtualization technologies that can flexibly cope with sudden and irregular network changes accompanying future service diversification and that can effectively use network resources are being studied.

  Network virtualization technology expresses a part of various physical resources such as optical fiber, cross-connect, router, etc. that make up a network with logical systems (routers, switches, optical transmission devices, etc.) and logical links. This is a technology that can be realized as a virtual network composed of virtual resources, or can be realized as a single virtual network by combining physical resources of networks provided by a plurality of network operators. By using this network virtualization technology, it becomes possible to share physical resources between virtual networks in accordance with changes in the environment such as the use state of physical resources and failures. In addition, if the allocation of physical resources to each virtual network can be determined optimally, it is possible to reduce the amount of resources and improve network availability.

  In Non-Patent Document 1, as a method of switching a physical resource (router) to a shared spare resource (spare router), a configuration (configuration; router system) is created after a path is temporarily duplicated and path information is exchanged. A case of switching to a reserve resource by changing the environment setting information) is disclosed. In this case, it is necessary for a node that performs processing for creating a configuration for switching and duplicating a route to always reserve a spare IF (interface) for switching the route. Therefore, there is a problem that the operation load and the resource amount of the node increase. To deal with this problem, in Non-Patent Document 1, as a method of switching a current router (virtual router) to a shared spare router, a route is made redundant in the transmission layer and a transfer packet is duplicated to obtain IP (Internet) A method is disclosed for enabling the reception of routing protocol messages, converging protocols, and synchronizing routes without changing the topology of the Protocol layer.

Hiroki Mori, 6 others, “Change of physical resource allocation to logical IP network in virtual optical transport control technology”, 2013 IEICE Communication Society, B-6-43, p.43, 2013 9 Moon

  However, in the method described in Non-Patent Document 1, when a current router is switched to a shared spare router, a transfer packet is used for duplication. There is a problem that a connection cannot be established for a protocol for exchanging messages using a connection.

  Therefore, according to the present invention, when a router (virtual router) that exchanges messages by establishing a TCP connection like BGP is switched to a spare router, the IP layer topology is not changed, and communication (for example, a session is performed) It is an object of the present invention to provide a technique for avoiding the disconnection of a).

  The network control device of the present invention is a network control device that is communicably connected to a first router and a second router, and a spare third router that is a switching destination of the first router, The network control device generates route information to be installed in the third router based on the route information acquired from the second router, and the third configuration having the same configuration as that of the first router is set. The generated route information is installed in a router.

  According to such a configuration, the network control device generates route information to be installed in the third router (standby router) as the switching destination based on the route information acquired from the second router (active router). To do. Then, the network control apparatus installs the generated route information in the third router that has the same configuration as that of the first router (active router). As a result, the network control device can synchronize the route information. When the first router is switched to the spare third router, the IP layer topology is not changed and communication is performed at the time of switching (for example, , Session) disconnection can be avoided.

  The network control device according to the present invention includes a route information acquisition unit that establishes communication with the second router to acquire route information, and the first router connected to the second router. Simulating the connection state of the router, installing the generated route information in the third router having the same configuration as that of the first router, and connecting the first router and the second router A connection state simulation unit that switches a transmission path between the second router and the third router.

  According to such a configuration, the connection state simulation unit of the network control device simulates the connection state of the first router and sets it to itself. As a result, the network control device can switch without switching communication (for example, session) with the third router to be switched at the time of switching the transmission path. Therefore, the network control device can avoid disconnection of communication at the time of switching without changing the topology of the IP layer when switching the first router to the spare third router.

  The network control device according to the present invention includes a route information acquisition unit that establishes communication with the second router to acquire route information, and the route information and storage unit acquired by the route information acquisition unit. A path computation unit that computes and generates path information to be installed in the third router having the same configuration as the first router, based on the topology information of the communication network stored in The generated route information is installed in the third router, and the transmission path between the first router and the second router is switched between the second router and the third router. And a route setting unit.

  According to such a configuration, the route calculation unit of the network control device calculates route information to be installed in the third router to be switched to. As a result, the network control device can switch without switching communication (for example, session) with the third router to be switched at the time of switching the transmission path. Therefore, the network control device can avoid disconnection of communication at the time of switching without changing the topology of the IP layer when switching the first router to the spare third router.

  According to the present invention, when switching a router to a spare router, it is possible to avoid disconnection of communication (for example, session) at the time of switching without changing the topology of the IP layer.

It is a figure which shows the virtual network system containing the network control apparatus of this embodiment, (a) represents a structural example, (b) represents a virtual network, (c) represents a physical network. It is a figure which shows the function example of the network control apparatus in 1st Embodiment. It is a figure which shows the example of a sequence in 1st Embodiment. It is a figure which shows the function example of the network control apparatus in 2nd Embodiment. It is a figure which shows the example of a sequence in 2nd Embodiment.

  A mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings as appropriate. In the following description, a logical system (router, switch, optical transmission device, etc.) on a virtual network is referred to as a logical system, and a logical link is referred to as a logical link.

(Virtual network system)
First, a configuration example of the virtual network system 100 including the network control device 1 according to the present embodiment will be described with reference to FIG.
As shown in FIG. 1A, the virtual network system 100 includes a plurality of optical transmission devices (nodes) 5 such as OXC (Optical cross-Connect) 5 and IP routers (nodes) 6 and communication between the optical transmission devices 5. A communication network 50 constituted by links indicating paths, and a network control device 1 connected to be communicable with each IP router 6 and each optical transmission device 5 are provided. Although one network control device 1 is described in FIG. 1A, it is constructed with a plurality of devices for each function to be described later, or a plurality of devices with the same function are provided for each type and number of nodes to be controlled. It does not matter.

  FIG. 1B shows a virtual network accommodated on the physical network shown in FIG. A plurality of virtual networks can be formed by appropriately dividing the IP router [virtual] 7 (logical system) and logical links 9 for one physical network. FIG. 1B shows a virtual network represented by a solid line and a virtual network represented by a dotted line.

  The physical network shown in FIG. 1C is composed of a system showing the optical transmission apparatus 5 and the IP router 6 and links connecting between the arbitrary optical transmission apparatuses 5 and between the optical transmission apparatus 5 and the IP router 6. The The system may include a switch (not shown). Also, in FIG. 1C, one IP router 6 is represented by the arrangement of IP routers [virtual] 7 indicating a logical system, and depending on the configuration of the virtual network shown in FIG. It may be represented by two dotted IP routers [virtual] 7. Also, each logical system is set as a start / end point, and a logical path 4 is set on the physical network via a transmission path 8 connecting the start / end points. The logical path 4 forms a logical link 9 in the virtual network shown in FIG.

  On the physical network, a virtual network having a previously planned topology composed of a plurality of logical systems and logical links 9 is arranged. When a certain logical system (IP router [virtual] 7) physically fails or maintenance work is performed, the logical system (IP router [virtual] 7) is changed to another physical system (another IP router [virtual] 7). Virtual] 7) is moved and switched over.

  Note that the network control device 1 shown in FIG. 1A has a function of controlling a virtual network (FIG. 1B) constructed on a physical network (FIG. 1C). The network control device 1 has a function of synchronizing the BGP path when the current IP router [virtual] 7 is switched to the spare router to be switched. Details of the functions of the network control device 1 will be described later.

  Next, in this embodiment, when a router (logical system) that exchanges messages by establishing a TCP connection as in BGP is switched to a backup router, there are two methods for executing the switching, and each method is as follows. Two types of network control devices that execute the above will be described. In the first embodiment, a network control apparatus that duplicates the status of the BGP peer of the current router and installs the BGP route information of the current router in the spare router to be switched will be described. In the second embodiment, based on the BGP route information acquired from the active router and the topology information of the physical network, the route information to be installed in the spare router at the switching destination is calculated, and the calculated BGP route information is converted into the switching destination information. A network control apparatus that executes a method of installing in a spare router will be described. In any of the embodiments, an iBGP (internal BGP) session is established between active routers (IP router [virtual] 7 shown in FIG. 1A) in the same virtual network, and BGP operates. Suppose you are.

(First embodiment)
In the first embodiment, a case will be described in which the network control device duplicates the BGP peer status of the current router and installs the BGP route information of the current router in the spare router to be switched to.
First, a function example of the network control device in the first embodiment will be described with reference to FIG. 2 (see FIGS. 1A, 1B, and 1C as appropriate). However, not all functions of the network control device 1 will be described, but functions related to the present invention will be described.

  The network control device 1 includes a processing unit 11, a storage unit 12, and a communication unit 13. The processing unit 11 includes a CPU (Central Processing Unit) and a main memory (not shown), expands an application program stored in the storage unit 12 to the main memory, and performs a resource allocation change calculation unit 111, a resource setting unit 112, A BGP peer establishment unit (route information acquisition unit) 113 and a BGP peer replication unit (connection state simulation unit) 114 are embodied.

  The resource allocation change calculation unit 111 includes physical network topology information and change information (physical failure, maintenance work, etc.) stored in a physical network DB (Database) 121 of the storage unit 12 described later, and a virtual network of the storage unit 12. With reference to the topology information and required performance function information of the virtual network stored in the DB 122, it has a function of calculating a resource allocation change destination. The topology information is information regarding each node (IP router 6 and optical transmission device 5) constituting the communication network 50 and the connection between the nodes. The required performance function information is information required for the number of IF (Interface) of the system, CPU performance, memory capacity, filter function, link capacity, and the like.

  The resource setting unit 112 has a function of setting a logical path and a logical system in the physical network based on the calculation result of the resource allocation change calculation unit 111.

  The BGP peer establishment unit 113 has a function of establishing a BGP session with an active router (IP router [virtual] 7 shown in FIG. 1A) and acquiring BGP route information. Further, the BGP peer establishing unit 113 has a function of installing the acquired BGP route information in the BGP peer duplicating unit 114 (described later).

  The BGP peer duplicating unit 114 has a function of executing BGP, and the status of the BGP peer of the current router (connection status; the status of the connection with the peer router set in the current router). It has a function of installing (advertisement) the obtained BGP route information in a spare router as a switching destination by duplicating (simulating) it in a pseudo manner. Further, the BGP peer duplicating unit 114 has a function of setting a configuration in a spare router and a function of executing setting / deleting of a static route.

The storage unit 12 is a storage device such as a hard disk, and stores a physical network DB 121 and a virtual network DB 122.
The physical network DB 121 stores topology information and change information (physical failure, maintenance work, etc.) of the physical network of the communication network 50.
The virtual network DB 122 stores virtual network topology information and required performance function information. Here, the required performance function information is information required for the number of interface (IF) of the system, CPU performance, memory capacity, filter function, link capacity, and the like.

  The communication unit 13 is a communication interface and has a function of transmitting / receiving various information to / from each node (the optical transmission device 5 and the IP router 6) of the communication network 50.

Next, a sequence example in the first embodiment will be described with reference to FIG. 3 (see FIG. 2 as appropriate). In FIG. 3, a case where the current router B (first router) is switched to the spare router C (third router) to be switched will be described.
In the communication network 50, the active router A (second router) and the router B have established an iBGP session. In addition, BGP is operating in the router A and the router B. Further, it is assumed that KEEPALIVE is exchanged between the router A and the router B at a predetermined cycle. Further, it is assumed that the network control device 1 can communicate with the routers A, B, and C.

In step S301, the BGP peer establishment unit 113 establishes an iBGP session (communication) with the router A that is not the switching target.
In step S302, the BGP peer establishment unit 113 acquires BGP route information from the router A.

In step S303, the BGP peer establishment unit 113 installs the acquired BGP route information in the BGP peer duplication unit 114.
In step S304, the BGP peer duplication unit 114 artificially duplicates the state of the BGP peer of the router A (the connection state of the router B connected to the router A).

In step S <b> 305, the BGP peer duplicating unit 114 sets the same configuration (configuration) as that of the router B in the router C.
In step S306, the router C and the router A synchronize an IGP (Interior Gateway Protocol) path (such as Open Shortest Path First (OSPF)) between the router C and the router A (the method of Non-Patent Document 1, etc.). Can be used.)

In step S307, the BGP peer duplicating unit 114 sets a static route to the network control device 1 in the router C.
In step S308, the BGP peer duplicating unit 114 establishes an iBGP session with the router C via a static route.

In step S309, the BGP peer duplicating unit 114 installs the BGP route information held by itself in the router C.
In step S310, the router C calculates a BGP best path (BGP route information for the router C) based on the installed BGP route information. Thereafter, KEEPALIVE is transmitted and received between the network control device 1 and the router C.

In step S311, the BGP peer duplicating unit 114 switches the transmission path between the router A and the router B between the router A and the router C.
In step S312, the BGP peer replication unit 114 deletes the static route from the router C.

In step S313, the router C changes the route of the iBGP peer between the router C and the router A based on the IGP route information. Then, KEEPALIVE is transmitted and received between the network control device 1 and the router C.
In step S314, the BGP peer establishment unit 113 disconnects the iBGP session with the router A.
Note that the processing of steps S311 to S313 needs to be performed within the BGP HoldTime.
In this way, the network control device 1 can switch the current router B to the spare router C to be switched to.

  As described above, in the first embodiment, the BGP peer duplicating unit 114 duplicates the state of the BGP peer of the router A and sets it to itself. As a result, the network control apparatus 1 can switch without switching the BGP session (communication) with the spare router C as the switching destination when the transmission path is switched. In addition, the network control device 1 automatically switches the BGP session route based on the IGP route even when the transmission path is switched or the static route is deleted by designating a loopback address as the BGP peer source address. Therefore, a session (communication) can be maintained. Therefore, the network control device 1 can avoid disconnection of the session at the time of switching without changing the topology of the IP layer.

(Second Embodiment)
Next, based on the BGP route information acquired from the current router and the topology information of the physical network, the route information to be installed in the spare router at the switching destination is calculated, and the calculated route information is transferred to the spare router at the switching destination. The case of installing will be described.
First, a function example of the network control device 1a in the second embodiment will be described with reference to FIG. 4 (refer to FIG. 1A and FIG. 2 as appropriate). However, not all functions of the network control device 1a will be described, but functions different from the first embodiment will be described, and descriptions of functions already described in the first embodiment will be omitted.

  The network control device 1a includes a processing unit 11a, a storage unit 12, and a communication unit 13. The processing unit 11a includes a route calculation unit 115 and a route setting unit 116 in addition to the resource allocation change calculation unit 111, the resource setting unit 112, and the BGP peer establishment unit 113 described in the first embodiment. The processing unit 11a is constituted by a CPU and a main memory (not shown), and an application program stored in the storage unit 12 is expanded in the main memory to embody each unit (111 to 113, 115, 116).

Here, functions of the route calculation unit 115 and the route setting unit 116 that are not provided in the network control device 1 of the first embodiment will be described.
Based on the BGP route information acquired by the BGP peer establishment unit 113, the physical network topology information and change information (physical failure, maintenance work, etc.) stored in the physical network DB 121, the route calculation unit 115 Has a function of calculating BGP route information to be installed in the router.
The route setting unit 116 has a function of installing the BGP route information calculated by the route calculation unit 115 in the spare router to be switched to. Further, the route setting unit 116 has a function of setting a configuration in a spare router.

Next, a sequence example in the second embodiment will be described with reference to FIG. 5 (see FIG. 2 as appropriate). In FIG. 5, as in the case of the first embodiment, a case where the current router B (first router) is switched to the spare router C (third router) to be switched will be described.
In the communication network 50, the working router A (second router) and the working router B have established an iBGP session. In addition, BGP is operating in the router A and the router B. Further, it is assumed that KEEPALIVE is exchanged between the router A and the router B at a predetermined cycle. The BGP peer establishment unit 113 establishes an iBGP session with the routers A and B, and collects BGP route information at a predetermined period or immediately before switching. Further, it is assumed that the network control device 1 can communicate with the routers A, B, and C.

In step S501, the BGP peer establishment unit (route information acquisition unit) 113 establishes an iBGP session (communication) with the router A that is not a switching target.
In step S502, the BGP peer establishment unit 113 acquires BGP route information from the router A.

In step S <b> 503, the BGP peer establishment unit 113 outputs the acquired BGP route information of the router A to the route calculation unit 115.
In step S504, the route calculation unit 115 uses the BGP route information of the router A acquired by the BGP peer establishment unit 113, the topology information and change information (physical failure, maintenance work, etc.) of the physical network stored in the physical network DB 121. Based on this, the BGP route information for the router C installed in the spare router C to be switched to is calculated and generated.

In step S505, the route setting unit 116 sets the same configuration as that of the router B in the router C.
In step S506, the router C and the router A synchronize the IGP path (OSPF or the like) between the router C and the router A (the method of Non-Patent Document 1 or the like can be used).

In step S507, the BGP peer establishment unit 113 establishes an iBGP session with the router C.
In step S508, the route calculation unit 115 outputs the BGP route information for the router C generated in step S504 to the route setting unit 116.

In step S509, the route setting unit 116 installs the BGP route information for the router C generated by the route calculation unit 115 in the router C.
In step S510, the router C sets BGP route information.

In step S511, the route setting unit 116 switches the transmission path between the router A and the router B between the router A and the router C.
In step S512, the BGP peer establishment unit 113 disconnects the iBGP session with the router A.
As a result, the network control device 1a can switch the router B to the spare router C to be switched to.

  As described above, in the second embodiment, the route calculation unit 115 calculates BGP route information to be installed in the switching destination router C. As a result, the network control device 1a can switch without switching the BGP session (communication) with the spare router C as the switching destination when the transmission path is switched. Therefore, the network control device 1a can avoid disconnection of the session (communication) at the time of switching without changing the topology of the IP layer.

  As described above, the network control device 1 [1a] of the first embodiment [second embodiment] obtains the BGP route information from the router A (active router) and, based on the obtained BGP route information, the switching destination. BGP route information to be installed in the router C (backup router) is generated. Then, the network control device 1 [1a] installs the generated BGP route information in the router C in which the same configuration as the router B is set. As a result, the network control device 1 [1a] can synchronize the BGP route information, and the transmission path between the router B and the router A can be changed between the router A and the router A while maintaining the BGP session. It is possible to switch between router C.

  In the methods shown in the first and second embodiments, switching of the router on which BGP is operating can be performed without changing the topology of the IP layer using the same configuration. Therefore, it is possible to realize a reduction in the amount of resources and equipment costs and a reduction in operation costs by sharing the reserve resources. Also, by avoiding session disconnection, routing re-convergence when switching transmission paths can be suppressed.

  The BGP case described in the present embodiment is an example of a routing protocol, and the present invention is also applicable when a routing protocol other than BGP is used. In addition, the present invention is not limited to a virtual network, and can be applied to a physical network.

1, 1a Network control device 4 Logical path 5 Optical transmission device (node)
6 IP router (node)
7 IP router [virtual]
DESCRIPTION OF SYMBOLS 8 Transmission path 9 Logical link 11 Processing part 12 Storage part 13 Communication part 100 Virtual network system 111 Resource allocation change calculating part 112 Resource setting part 113 BGP peer establishment part (path information acquisition part)
114 BGP peer replication unit (connection state simulation unit)
115 Route Calculation Unit 116 Route Setting Unit 121 Physical Network DB
122 Virtual network DB

Claims (3)

A network control device communicably connected to a first router and a second router and a spare third router which is a switching destination of the first router,
The network controller is
Based on the route information acquired from the second router, the route information to be installed in the third router is generated, and the generated information is generated in the third router having the same configuration as that of the first router. A network control device characterized by installing route information. The network controller is
A route information acquisition unit that establishes communication with the second router and acquires route information;
Simulates the connection state of the first router connected to the second router, and installs the generated route information in the third router having the same configuration as the first router. And a connection state simulator that switches a transmission path between the first router and the second router between the second router and the third router. 2. The network control device according to 1. The network controller is
A route information acquisition unit that establishes communication with the second router and acquires route information;
Based on the path information acquired by the path information acquisition unit and the topology information of the communication network stored in the storage unit, installed in the third router having the same configuration as the first router A route calculation unit that calculates and generates route information to be
The generated route information is installed in the third router, and the transmission path between the first router and the second router is switched between the second router and the third router. The network control device according to claim 1, further comprising a route setting unit.

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