JP2009049925A - Rerouting method, rerouting program, and routing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To calculate a rerouting path in which an accommodated traffic quantity after rerouting, the cost of cutting a path and the cost of connecting the path at the time of rerouting, and the cost of cutting traffic caused by the cutting of the path at the time of rerouting are simultaneously considered. <P>SOLUTION: A routing apparatus acquires network information from each node within a network, stores the acquired network information, calculates an objective function having parameters of (1) an accommodated traffic quantity after rerouting, (2) the cost of cutting a path and the cost of connecting the path at the time of rerouting, and (3) the cost of cutting the traffic caused by the cutting of the path at the time of rerouting, and calculates and outputs the rerouting path that maximizes the objective function and a rerouting procedure for the rerouting path. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a path rerouting technique on a network.

Conventionally, when rerouting a route on a network path (for example, an MPLS (Multi-Protocol Label Switching) path, an SDH (Synchronous Digital Hierarchy) path, etc.), a routing device (path management device) first satisfies the requirements. Among the routes, (1) a route that maximizes the amount of accommodated traffic after rerouting is determined. (2) Among the transition procedures to the determined route, the path disconnection cost or connection cost when rerouting to the determined route, the traffic disconnection cost due to the path disconnection, etc. are minimized. A path transfer procedure is determined (see Non-Patent Document 1).
Yongbing Zhang et al., “Trafic-Based Reconfiguration for Logical Topologies in Large-Scale WDM Optical Networks”, Journal Of Lightwave Technology, vol.23, No.10, Ocrober 2005

  However, the above-described technology has (1) maximization of the amount of accommodated traffic after rerouting as a priority condition, and (2) path disconnection cost and connection cost when rerouting, traffic disconnection cost due to the path disconnection, etc. Is minimized after (1). That is, (1) and (2) are not considered simultaneously. Therefore, for example, although the amount of accommodated traffic after rerouting is not the maximum, it is possible to calculate a route that can minimize the path disconnection cost and connection cost when rerouting, the traffic disconnection cost due to the path disconnection, etc. could not.

  Therefore, the present invention solves the above-mentioned problem, (1) maximization of the accommodated traffic amount after rerouting, (2) path disconnection cost and connection cost when rerouting, and traffic disconnection due to the path disconnection It is an object of the present invention to provide a rerouting path that simultaneously considers minimization of cost and the like and a means for calculating a rerouting procedure for the rerouting path.

  According to the first aspect of the present invention, for each link connecting each node of the network, identification information of the node connected by the link and link information indicating the maximum bandwidth of the link, and each node in the network A routing device including a storage unit that stores topology information, a list indicating link information passing through the path, and path information indicating a bandwidth of the path, for each path established between the nodes. Via the input / output unit, an input of a traffic change request indicating identification information of a start node and an end node of a new path and a bandwidth requested for the new path is received, and the link information, the topology information, and the With reference to the path information, one or more paths passing through the link on the path of the new path are specified, and the specified path When rerouting of another path is necessary along with the rerouting, a rerouting pattern indicating the rerouting destination path of the other path is calculated, and the route of the calculated rerouting pattern is Storing in the storage unit, calculating a pattern of the rerouting procedure when rerouting the path in the network to the route of the calculated rerouting pattern, storing the pattern in the storage unit, and each pattern of the calculated rerouting procedure In addition, in the execution of the pattern of the rerouting procedure, at least one of a path to be disconnected or connected and a path to which traffic is disconnected due to the disconnection of the path is calculated, and the accommodated traffic of each path in the route of the calculated rerouting pattern When, For each of the calculated rerouting procedure patterns, a predetermined objective function is calculated using at least one of the path to be disconnected or connected and the path to which traffic is disconnected due to the path disconnection, from the storage unit, Read the path of the rerouting pattern that maximizes the calculated objective function and the pattern of the rerouting procedure to the path of the rerouting pattern, and read the path of the rerouting pattern and the pattern of the rerouting procedure to the path of the rerouting pattern, A rerouting method is characterized in that a rerouting calculation result for the traffic change request is output.

  According to the sixth aspect of the present invention, for each link connecting each node of the network, identification information of the node connected by the link and link information indicating the maximum bandwidth of the link, and each node in the network For each path established between the nodes, a storage unit storing topology information, a list indicating link information passing through the path, and path information indicating the bandwidth of the path, and an input / output unit A traffic change request information acquisition unit that receives an input of a traffic change request indicating identification information of a start node and an end node of a new path, and a bandwidth required for the new path, and a rerouting destination of the path A rerouting calculation unit for calculating a route and a rerouting procedure for the route, and the rerouting calculation Refers to the link information, the topology information, and the path information, and (1) specifies one or more paths that pass through a link on the route of the new path, and (2) a rerouting destination of the specified path And when the rerouting of another path is necessary along with the rerouting, a rerouting pattern indicating a rerouting destination path of the other path is calculated, and (3) the path of the calculated rerouting pattern is calculated. Storing in the storage unit, (4) calculating a pattern of a rerouting procedure for rerouting a path in the network to a route of the calculated rerouting pattern, storing the pattern in the storage unit, and (5) calculating the calculation For each rerouting pattern that has been performed, the rerouting procedure pattern is disconnected in the execution of the rerouting procedure pattern. Calculates at least one of a path to be connected and a path to which traffic is cut off due to disconnection of the path, and (6) accommodation traffic of each path in the route of the calculated rerouting pattern, and the calculated rerouting procedure For each pattern, a predetermined objective function is calculated by using at least one of the path to be disconnected or connected and the path to which traffic is disconnected by disconnecting the path, and (7) the calculated object is stored from the storage unit. Read the path of the rerouting pattern that maximizes the function and the pattern of the rerouting procedure to the path of the rerouting pattern, and change the traffic change to the path of the read rerouting pattern and the pattern of the rerouting procedure to the path of the rerouting pattern. The routing device is characterized in that it outputs the result of rerouting calculation for the request.

  By doing in this way, the routing device maximizes the amount of accommodated traffic after rerouting, the path disconnection cost and connection cost when rerouting to the path route, the traffic disconnection cost due to the path disconnection, etc. It is possible to calculate a rerouting path considering minimization and a rerouting procedure to this rerouting path.

The invention according to claim 2 is the rerouting method according to claim 1, wherein the objective function is defined by the following equation (1):
F = f (a) − {total value of at least one of g (b) and h (c)} (1)
F: Objective function f (a): Function relating to accommodation traffic of each path in the route of the calculated rerouting pattern g (b): Operation procedure amount penalty function in the pattern of the rerouting procedure h (c): of the rerouting procedure Penalty function for occurrence of traffic disconnection due to path disconnection in pattern a: Parameters relating to each path in the route of the rerouting pattern b: Parameters relating to paths to be disconnected or connected in execution of the pattern of the rerouting procedure c: Pattern of the pattern of the rerouting procedure Parameters relating to paths in which traffic is disconnected due to path disconnection in execution The storage unit stores the f (a) and at least one of the g (b) and the h (c). The routing method was used.

  According to such a method, the routing device can calculate an objective function in consideration of an operation procedure amount penalty associated with rerouting and a traffic disconnection penalty.

  According to a third aspect of the present invention, in the rerouting method according to the second aspect, the routing device includes the f (a), the g (b), and the h (c) stored in the storage unit. 3. The rerouting method according to claim 2, wherein one of the two is changed based on an instruction input from the input / output unit.

  According to such a method, the network operation manager or the like desires f (a), g (b), and h (c) when calculating the objective function shown in the above equation (1) in the routing device. Can be changed to

  According to a fourth aspect of the present invention, in the rerouting method according to any one of the first to third aspects, the routing device is configured such that the calculated maximum value of the objective function is the value before the new path is set. When the value is smaller than the value of the objective function calculated using the total bandwidth of each path in the network, the rerouting calculation result includes a message rejecting the addition of the new path.

  According to such a method, when it is determined in the routing device that the objective function is not improved even if a new path is set in the network, this can be notified to the network operation manager or the like. That is, a network operation manager or the like can know that the objective function related to the network is not maximized even if a new path is set in the network.

  According to a fifth aspect of the present invention, there is provided a rerouting program that causes the routing device that is a computer to execute the rerouting method according to any one of the first to fourth aspects.

  According to such a program, it is possible to cause a general computer to execute the rerouting method according to any one of claims 1 to 4.

  According to the present invention, in a network, the amount of accommodated traffic after rerouting is maximized, the path disconnection cost or connection cost (path disconnection connection cost) when rerouting to the path route, and the traffic due to the path disconnection It is possible to calculate a rerouting path and a rerouting procedure to this rerouting path simultaneously considering minimization of the disconnection cost (traffic disconnection cost).

  Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described with reference to the drawings.

<System configuration example>
FIG. 1 is a diagram showing a configuration example of a system including a routing device according to an embodiment of the present invention. As shown in FIG. 1, the system calculates the path of the path connecting the network 3 composed of the nodes 2 (2A, 2B, 2C, 2D, 2E, 2F) and each node 2, and this calculation is performed. A routing apparatus 1 that instructs path establishment on a route and a network operator terminal 4 that inputs various instructions to the routing apparatus 1 are configured. The node 2 and the routing device 1 are connected by a predetermined communication path. Further, the routing device 1 and the network operator terminal 4 are also communicably connected via a predetermined communication path. The node 2 is, for example, an SDH (Synchronous Digital Hierarchy) switch or an MPLS (Multi-Protocol Label Switching) router, and the path is an SDH path or an MPLS path. Here, a case where the path is an SDH path will be described as an example.

  Here, as illustrated in FIG. 1, in the network 3 before rerouting, 2.5 G (bps) between the nodes 2A and 2F, 10 G (bps) between the nodes 2A and 2D, and 5 G (between the nodes 2B and 2C ( bps) and a path of 2.5G (bps) is set between the nodes 2C and 2D. In addition, the maximum bandwidth of a link (physical link) connecting these nodes is 10 G (bps).

  Here, the flow of each information in this system will be described with reference to FIG. FIG. 2 is a diagram for explaining the flow of each information in the system of FIG.

  As shown in FIG. 2, (1) First, the routing device 1 receives a traffic change request (new path setting request) from the network operator terminal 4 or the like through the operation information interface 111. The new path setting request indicates the start and end nodes of the new path, the bandwidth required for the new path, and the like.

  (2) Next, the routing device 1 transmits a network information request message to the network 3 (router 2 in FIG. 1) through the network information interface 112.

  (3) The routing device 1 receives network information as a response to the network information request message through the network information interface 112. The network information includes physical information (link information and topology information) of the network 3, path information set for each node 2, and the like.

  (4) Thereafter, the routing device 1 calculates the rerouting route of the network 3 based on the received network information and the traffic change request, and calculates the rerouting route calculation result (rerouting calculation result) as the operation information interface. In step 111, the data is transmitted to the network operator terminal 4 or the like. Although the description is omitted here, the routing device 1 thereafter instructs the establishment of a path between the nodes 2 based on an instruction input from the network operator terminal 4 or the like.

<Configuration of routing device>
Next, the configuration of the routing device 1 in FIG. 1 will be described with reference to FIG. FIG. 3 is a block diagram showing the configuration of the routing device of FIG.

  As illustrated in FIG. 3, the routing device 1 includes an input / output unit 11, a processing unit 12, and a storage unit 13.

  The input / output unit 11 acquires network information from each node 2 and inputs / outputs data to / from terminals connected to the outside of the routing device 1 (such as the network operator terminal 4 in FIG. 1). Interface. Such an input / output unit 11 includes an operation information interface 111 and a network information interface 112.

  The operation information interface 111 receives an input of a traffic change request from the network operator terminal 4 in FIG. As described above, this traffic change request is, for example, a request for setting a new path, and includes the identification information of the start node and the end node of the new path, the bandwidth required for the new path, and the like. Further, the operation information interface 111 shows the rerouting calculation result indicating the rerouting route calculated by the processing unit 12 and the transition procedure to the rerouting route based on the traffic change request, and the network operator terminal 4 in FIG. Output to.

  The network information interface 112 acquires network information from each node 2 in FIG. As described above, the network information includes physical information (link information and topology information) of the network 3, path information set in each node 2, and the like.

  The input / output unit 11 may have an interface function for connecting to an input device (not shown) such as a keyboard or a mouse, an output device (not shown) such as a liquid crystal monitor, or the like.

  The processing unit 12 controls the entire routing device 1 and controls the input / output unit 11 and the storage unit 13 and processes input information. Further, the processing unit 12 acquires network information via the input / output unit 11 and outputs a path setting instruction to each node 2 by signaling. The processing unit 12 includes a traffic change request information acquisition unit 121, a network information request unit 122, a network information acquisition unit 123, a parameter conversion unit 124, a rerouting calculation unit 125, and a rerouting calculation result information reporting unit 126. Consists of including.

  When the traffic change request information acquisition unit 121 acquires the traffic change request described above via the operation information interface 111, the traffic change request information acquisition unit 121 stores the traffic change request information in the traffic change request information storage unit 131 (described later) of the storage unit 13.

  The network information request unit 122 transmits a network information request message to each node 2 via the network information interface 112.

  The network information acquisition unit 123 acquires network information via the network information interface 112 as a response to the network information request message. Then, the acquired network information is stored in the network information storage unit 132 (described later) of the storage unit 13.

  When the rerouting calculation unit 125 calculates the objective function for the rerouting calculation, the parameter conversion unit 124 refers to the parameter conversion policy (described later) stored in the parameter conversion policy storage unit 133 and (1) the entire network 3 A value for using the accommodated traffic amount (bandwidth), (2) the total bandwidth of the disconnected connection path, and (3) the total bandwidth of the traffic disconnected path as parameter values of this objective function is read.

  The rerouting calculation unit 125 refers to the topology information, link information, path information, and the like stored in the network information storage unit 132 of the storage unit 13, and sets a rerouting route for setting a new path indicated in the traffic change request information and A rerouting procedure (rerouting calculation result) for rerouting the route is calculated. The rerouting path calculated here and the rerouting procedure for rerouting to the path maximize the predetermined objective function (details will be described later). The processing procedure of rerouting calculation using this objective function will be described later using a flowchart. The rerouting calculation unit 125 stores the rerouting calculation result here in the rerouting calculation result information storage unit 134 (described later) of the storage unit 13.

  The rerouting calculation result information reporting unit 126 transmits the rerouting calculation stored in the rerouting calculation result information storage unit 134 of the storage unit 13 to the network operator terminal 4 or the like in FIG. 1 via the operation information interface 111 described above.

  The function of the processing unit 12 may be realized by software or may be realized by hardware. In other words, a CPU (Central Processing Unit) of the routing device 1 may be realized by executing a rerouting program stored in the storage unit 13, or by using a dedicated circuit that realizes the function of the processing unit 12. It may be realized.

  Next, the storage unit 13 will be described. The storage unit 13 includes a traffic change request information storage unit 131, a network information storage unit 132, a parameter conversion policy storage unit 133, and a rerouting calculation result information storage unit 134 in a predetermined area.

  The traffic change request information storage unit 131 stores the traffic change request described above.

  The network information storage unit 132 stores the network information described above. As described above, this network information includes physical information (topology information and link information) of the network 3, path information, and the like.

  The topology information is information indicating the identification information of the node 2 installed in the network 3 and what kind of link the nodes are connected to. As the identification information of the node 2, an IP address, a MAC (Media Access Control) address, or the like is used. Based on such topology information, the routing device 1 grasps a network configuration as shown in FIG. 1, for example.

  As illustrated in Table 1, the link information includes, for each piece of identification information (link ID) of the link constituting the network 3, the maximum allowable bandwidth (maximum bandwidth), the A-end node ID, and the A-end node IF of this link. (Interface) Information indicating an ID, a Z-end node ID, a Z-end node IF ID, a link cost, and the like. Further, for example, an IP address or the like is used as the node ID and the node IF ID. The link information may include information on the type of link interface (10G-Ethernet (registered trademark), STM (Synchronous Transfer Mode) -16, etc.).

  The path information is information indicating the link ID and bandwidth of the link used for the current path for each path ID of the path (current path) currently set in the network 3. As illustrated in Table 2, this path information is information indicating a start point node ID, a start point node IF ID, an end point node ID, an end point node IF ID, a via link ID list, a bandwidth, and the like for each path ID of the current path. It is. Based on such path information, the routing device 1 grasps a path (see FIG. 1) set in the network 3. In addition to the information described above, the path information may include information on the use start date and time and use end date and time of each path, use bandwidth at each date and time, and reservation information on a path to be set in the future. From such information, the routing device 1 can grasp how much bandwidth is occupied from when to when in each link of the network 3.

  The parameter conversion policy storage unit 133 stores the parameter conversion policy. This parameter conversion policy includes (1) the traffic volume (bandwidth) of the entire network 3, (2) path disconnection connection cost (for example, total bandwidth of paths to be disconnected or connected) and (3) traffic disconnection cost ( For example, a value for using a total bandwidth of a path from which traffic is cut off by connection of the path as a parameter value of the above-described objective function is shown. In this parameter conversion policy, for example, when calculating the objective function, (1) the amount of traffic (bandwidth) of the entire network 3 is “1” per 1 Gbps of the accommodated path, and (2) the disconnection connection cost of the path The policy is to calculate “0.05” per 1 Gbps of the path to be disconnected or connected, and (3) the traffic disconnection cost to be calculated using the value “0.1” per 1 Gbps of the path from which the traffic is disconnected. .

  The parameter conversion policy can be changed based on an instruction input from the input / output unit 11. In this way, for example, the operation manager of the network 3 can obtain the rerouting calculation result of the network 3 optimized as desired by the operation manager of the network 3 or the like.

  The rerouting calculation result information storage unit 134 stores the rerouting calculation result by the rerouting calculation unit 125. Details of the rerouting calculation result will be described later.

  The storage unit 13 is realized by a storage device such as a RAM (Random Access Memory), a flash memory, and an HDD (Hard Disk Drive).

  Next, the operation procedure of the routing apparatus 1 will be described with reference to FIGS. 1, 3, 6 and 7 and with reference to FIGS. FIG. 4 is a flowchart showing an operation procedure of the routing apparatus of FIG. FIG. 5 is a flowchart showing details of the rerouting calculation process in S408 of FIG. 6 and 7 are diagrams illustrating the network after the rerouting of the path of FIG.

  First, when a traffic change request occurs in the network 3 of FIG. 1 (S401), the routing device 1 acquires a traffic change request from the operation information interface 111 by the traffic change request information acquisition unit 121 (S402).

  In this traffic change request, for example, as indicated by a balloon 420 in FIG. 4, 2.5 G (bps) traffic newly flows between the nodes 2A and 2C, and 5 G (bps) traffic flows between the nodes 2F and 2D. This is a request that you want to (set a path). As described above, this traffic change request is transmitted from the operation manager terminal 4 or the like.

  Next, the traffic change request information acquisition unit 121 stores the traffic change request acquired in S402 in the traffic change request information storage unit 131 (S403).

  Subsequently, the routing device 1 transmits a network information request message to each node 2 from the network information interface 112 by the network information request unit 122 (S404).

  Then, the routing device 1 acquires from each node 2 by the network information acquisition unit 123 (S405), and stores the acquired network information in the network information storage unit 132 (S406).

  For example, the network information acquired here includes (1) physical information and (2) path information of the network 3 as indicated by a balloon 430. (1) The physical information is, for example, the nodes 2A, 2B, 2C, 2D, 2E, 2F, the nodes 2A, 2B, the nodes 2B, 2C, the nodes 2C, 2D, the nodes 2D, 2E, the nodes 2E, 2F, and the node 2F , 2A, nodes 2B, 2F and nodes 2C, 2E are connected by a link having a maximum bandwidth of 10 G (bps). Also, (2) path information includes, for example, “10G (bps) path via nodes 2A, 2B, 2F, 2E, 2D, 2.5G (bps) path via nodes 2A, 2F, node 2B , 2C passes through 5G (bps) path, and nodes 2C and 2D pass through 2.5G (bps) path respectively. The routing device 1 grasps the topology, path, and the like of the network 3 as shown in FIG. 1 based on such network information.

  Then, the rerouting calculation unit 125 refers to such network information and the traffic change request stored in the traffic change request information storage unit 131 to determine whether or not rerouting is necessary for the path of the network 3 ( S407). At this time, whether the rerouting is necessary or not is determined when the rerouting calculation unit 125 adds a new path indicated in the traffic change request to the network 3 so that the bandwidth of the link on the route of the new path is the maximum bandwidth ( For example, the determination is made based on whether or not it exceeds 10 G (bps). Note that the value of the maximum bandwidth of each link indicated in the link information is referred to as the value of the maximum bandwidth of the link. Here, when a new path indicated in the traffic change request is added to the network 3, the bandwidth of the link on the route of the new path is determined to exceed the maximum bandwidth of the link (for example, 10G (bps)). (Yes in S407), the process proceeds to S408. Then, the rerouting calculation unit 125 performs rerouting calculation (S408). Then, the process proceeds to S409. This rerouting calculation (S408) will be described later with reference to FIG.

  On the other hand, when it is determined that rerouting is not necessary (No in S407), that is, even if a new path indicated in the traffic change request is added to the network 3, the bandwidth of the link on the route of this new path is the maximum of the link. When the bandwidth (for example, 10 G (bps)) is not exceeded, S408 is skipped and the process proceeds to S409.

  The rerouting calculation unit 125 stores the rerouting calculation result (the calculation result of S408 and the determination result when it is determined that rerouting is not necessary in S407) in the rerouting calculation result information storage unit 134 (S409).

  The rerouting calculation result here includes (1) path information after rerouting, (2) an answer to the traffic change request, and (3) a path transition procedure, as illustrated in the balloon 440.

  (1) The path information after rerouting is, for example, the path illustrated in FIG. 6, that is, the path of 10 G (bps) passing through the nodes 2A, 2F, 2E, and 2D, and the nodes 2A, 2B, and 2F. The information includes a 2.5 G (bps) path, a 5 G (bps) path passing through the nodes 2B and 2C, and a 2.5 G (bps) path passing through the nodes 2C and 2D.

  The response to the traffic change request is, for example, a 2.5 G (bps) path passing through the nodes 2 A, 2 B, and 2 C in response to a request of 2.5 G (bps) between the nodes 2 A and 2 C. In response to a request to set or a request of 5G (bps) between the nodes 2F and 2D, the response is a rejection (a path cannot be set).

Furthermore, (3) the path transfer procedure is, for example,
1. Disconnect 2.5G (bps) path via nodes 2A and 2F,
2. Set a 10G (bps) path via the nodes 2A, 2F, 2E, 2D,
3. Disconnect the 10G (bps) path via the nodes 2A, 2B, 2F, 2E, 2D,
4. A 2.5G (bps) path passing through the nodes 2A, 2B, and 2F is set.
This is the procedure.

  After S409, the rerouting calculation result information reporting unit 126 transmits the rerouting calculation result in the rerouting calculation result information storage unit 134 to the network operator terminal 4 through the operation information interface 111 (S410).

  In this way, when the network operation manager receives the rerouting calculation result from the network operator terminal 4, it is possible to instruct the routing apparatus 1 to set the path based on this content.

  Next, the rerouting calculation of S408 in FIG. 4 will be described with reference to FIG.

  First, the rerouting calculation unit 125 refers to the network information in the network information storage unit 132, and for a link that exceeds the maximum bandwidth of the link due to the addition of a new path indicated in the traffic change request, the path passing through the link Is identified (S501).

  For example, when a new path of 2.5 G (bps) is set as it is between the nodes 2A and 2C of the network 3 in FIG. 1, the maximum bandwidth of this link exceeds 10 G (bps) in the link connecting the nodes 2A and 2B. End up. Therefore, the path passing through this link (path passing through the nodes 2A, 2B, 2F, 2E, 2D) is specified. In addition, when a new path of 5G (bps) is set between the nodes 2F and 2D, the link connecting the nodes 2F and 2E and the link connecting the nodes 2E and 2D exceed the maximum bandwidth 10G (bps) of this link. End up. Therefore, the path passing through this link (path passing through the nodes 2A, 2B, 2F, 2E, 2D) is specified.

  Next, the rerouting calculation unit 125 refers to the network information in the network information storage unit 132, and calculates the rerouting destination route of the path specified in S501. The rerouting destination path calculated here also assumes that the bandwidth of each link of the rerouting destination is within the maximum bandwidth of the link. If there are a plurality of rerouting destinations, each rerouting destination is stored in a predetermined area of the storage unit 13 as a rerouting pattern. When there is another path that needs to be rerouted along with this rerouting, the rerouting destination route of this path is also calculated, a rerouting pattern is calculated, and stored in a predetermined area of the storage unit 13 (S502).

  For example, in FIG. 1, when a path that passes through the nodes 2A, 2B, 2F, 2E, and 2D is rerouted to a path that passes through the nodes 2A, 2B, 2C, and 2D, a 5G (bps) path is already included in this path. Since there is a 2.5 G (bps) path, the maximum bandwidth of 10 G (bps) is exceeded in the link used by each path. Accordingly, the rerouting destination route is also calculated for the 5G (bps) path (path between the nodes 2B and 2C) and the 2.5G (bps) path (nodes 2C and 2D).

  Next, the rerouting calculation unit 125 calculates, for each rerouting pattern calculated in S502, the total value (accommodated traffic amount) of the path bandwidth of this rerouting pattern (S503). The rerouting calculation unit 125 stores the accommodated traffic amount for each rerouting pattern in a predetermined area of the storage unit 13.

  Then, the rerouting calculation unit 125 reads the route of the rerouting pattern calculated in S502 from the storage unit 13, and calculates a rerouting procedure to the route of the rerouting pattern (S504). Here, if there are a plurality of rerouting procedures to the route of the rerouting pattern, the rerouting calculation unit 125 stores the plurality of rerouting procedures in a predetermined area of the storage unit 13 as a pattern of the rerouting procedure to the rerouting route.

  Thereafter, the rerouting procedure pattern calculated in S504 is read from the storage unit 13, and for each rerouting procedure pattern, (1) a path to be disconnected or connected (disconnected path) and (2) path disconnection. A path to which traffic is cut (traffic cut path) is calculated (S505).

Then, the rerouting calculation unit 125 reads the rerouting pattern and the rerouting procedure pattern stored in the storage unit 13, and reroutes the path to the rerouting pattern that maximizes the objective function shown in the following equation (2). Calculate rerouting procedures.
Objective function = accommodated traffic amount × A1- (total bandwidth of disconnected connection path × A2 + total bandwidth of traffic disconnection path × A3) (2)
A1: Value for using the value of the accommodated traffic volume as a parameter value of this objective function A2: Value for using the total bandwidth of the disconnected connection path as this parameter value of this objective function A3: Total bandwidth of the traffic cutoff path A value to use as the parameter value for this objective function

  Note that A1, A2, and A3 are set in the parameter conversion policy of the parameter conversion policy storage unit 133, and are read by the parameter conversion unit 124.

  For example, when A1 = “1” per path 1 G (bps), A2 = “0.05” per path 1 Gbps, and A3 = “0.6” per path 1 Gbps, rerouting as shown in FIG. The accommodated traffic amount is “2.5 G (bps) +2.5 G (bps) +5 G (bps) +2.5 G (bps) +10 G (bps)”. When the routing device 1 reroutes the path shown in FIG. 1 by the rerouting procedure shown in (3) of the balloon 440 in FIG. 4, the disconnected connection path is 2.5 G (bps) between the nodes 2A and 2F. And a path of 10 G (bps) between the nodes 2A and 2D (see the path indicated by the broken line arrow in FIG. 6). Therefore, the total bandwidth of the disconnected connection path is “10 G (bps) +2.5 G (bps)”. The traffic cut path (path from which traffic was cut during rerouting) is a 2.5 G (bps) path between the nodes 2A and 2F. Therefore, the objective function when performing rerouting as shown in FIG. 6 is as follows.

  Objective function value = (2.5 + 2.5 + 5 + 2.5 + 10) × 1 − {(2.5 + 10) × 0.05 + 2.5 × 0.6} = 20.375

  On the other hand, when the routing device 1 performs rerouting as shown in FIG. 7, the accommodated traffic volume is “10 G (bps) +5 G (bps) +2.5 G (bps) +2.5 G (bps) +5 G (bps)”. is there. The disconnected connection path includes a 10G (bps) path between the nodes 2A and 2D, a 5G (bps) path between the nodes 2B and 2C, and a 2.5G (bps) path between the nodes 2C and 2D. Yes (see the path in which the route indicated by the broken-line arrow in FIG. 7 is changed). Therefore, the total bandwidth of the disconnected connection path is “10 G (bps) +5 G (bps) +2.5 G (bps)”. Also, the traffic cut path (the path from which traffic was cut during rerouting) is a 5 G (bps) path between the nodes 2B and 2C and a 2.5 G (bps) path between the nodes 2C and 2D. Therefore, the objective function when performing rerouting as shown in FIG. 7 is as follows.

  Objective function value = (10 + 5 + 2.5 + 2.5 + 5) × 1 − {(10 + 5 + 2.5) × 0.05 + (5 + 2.5) × 0.6} = 19.625

  Thus, in the prior art, in the network 3 shown in FIG. 1, a rerouting pattern as shown in FIG. 7 in which the amount of accommodated traffic in the network 3 increases is selected. According to the routing device 1 of the present embodiment, Using the objective function shown in the above equation (1), a rerouting pattern (rerouting pattern shown in FIG. 6) that maximizes the value of the objective function is selected as a route.

  Returning to the description of FIG. After S506, the rerouting calculation unit 125 calculates the value of the objective function when the new path is not added, and the value of the objective function maximized at S506 exceeds the value of the objective function when the new path is not added. Whether or not (S507). That is, the objective function is calculated based on the bandwidth of the current path of the network 3, and it is determined whether or not the value of the objective function is larger than the maximum value of the objective function when a new path is added.

  Here, when the rerouting calculation unit 125 determines that the value of the objective function maximized in S506 exceeds the value of the objective function when this new path is not added (Yes in S507), the rerouting calculation unit 125 The route of the rerouting pattern that maximizes the objective function calculated in S506 and the rerouting procedure to this route are output as the rerouting calculation result (S508).

  On the other hand, when the rerouting calculation unit 125 determines that the value of the objective function maximized in S506 does not exceed the value of the objective function when this new path is not added (No in S507), the new path setting is rejected. A message to that effect is output as a rerouting calculation result (S509). For example, as shown in (2) of the balloon 440 in FIG. 4 described above, the rerouting calculation unit 125 displays the rerouting calculation result including the content “rejected for a request of 5 G (bps) between the nodes 2F and 2D”. Output. As a result, the network operation manager or the like can know that the objective function cannot be maximized even if a new path is added.

  In the network 3 shown in FIG. 1, when the new path is not set and rerouting is not performed, the value of the objective function is “10 + 5 + 2.5 + 2.5 = 20”, and this value is as shown in FIG. The value of the objective function when performing rerouting is not exceeded. In other words, the value of the objective function is larger when a new path is set. Therefore, the rerouting calculation unit 125 accepts the setting of a new path.

  By doing in this way, the routing apparatus 1 can calculate the rerouting pattern which considered simultaneously the accommodation traffic amount of the network 3, and costs, such as path | route disconnection connection and traffic cutting | disconnection. That is, when the amount of traffic accommodated in the network 3 is considered as “income” in the network 3, the cost of disconnecting a path or disconnecting traffic as “expenditure” in the network 3, and the value of the objective function as “gain” in the network 3 According to the routing device 1 of the present embodiment, a rerouting pattern with higher gain can be found.

  In the above-described embodiment, the routing device 1 uses both the value of the total bandwidth of the disconnected connection path and the value of the total bandwidth of the traffic disconnected path when calculating the objective function. Of these, calculation may be performed using one of the values.

  Further, the number of disconnected connection paths, the number of traffic disconnected paths, and the like may be used instead of the total bandwidth of disconnected connection paths and the total bandwidth of traffic disconnected paths. In addition, the rerouting calculation unit 125 may use other methods to quantify the cost when traffic is disconnected due to path disconnection or connection, or path disconnection, and calculate the objective function using the quantified value. Good.

  Further, in the above-described embodiment, when the routing device 1 performs rerouting calculation, first, a rerouting pattern that can be considered and a procedure for performing rerouting to the path of the rerouting pattern are calculated, and then the rerouting that maximizes the objective function The pattern and the procedure for rerouting to the route of the rerouting pattern are selected (searched), but the present invention is not limited to this. For example, this rerouting pattern, the calculation of the procedure for rerouting to the path of the rerouting pattern, and the calculation of the objective function are performed in parallel, and the rerouting pattern that maximizes the objective function and the rerouting to the path of the rerouting pattern are performed. The procedure to be performed may be calculated.

In the above embodiment, the objective function is
Objective function = accommodated traffic amount × A1- (total bandwidth of disconnected connection path × A2 + total bandwidth of traffic disconnection path × A3) (2)
A1: Value for using the value of the accommodated traffic volume as a parameter value of this objective function A2: Value for using the total bandwidth of the disconnected connection path as this parameter value of this objective function A3: Total bandwidth of the traffic cutoff path Is described as an example of a value for use as the parameter value of the objective function, but is not limited thereto. For example, the following equation (3) may be used as the objective function.

F = f (a) − {total value of at least one of g (b) and h (c)} Expression (3)
F: Objective function f (a): Function related to accommodated traffic of each path in the route of the calculated rerouting pattern g (b): Operation procedure amount penalty function in the pattern of rerouting procedure h (c): Path in the pattern of rerouting procedure Penalty function for disconnection of traffic due to disconnection of a: a: parameter relating to each path in the route of the rerouting pattern b: parameter relating to a path to be disconnected or connected in execution of the pattern of the rerouting procedure c: Parameters related to paths where traffic is cut off Also, f (a), g (b), and h (c) are stored in the parameter conversion policy.

Here, a: parameters related to each path in the route of the rerouting pattern are the total number of paths in the route of the rerouting pattern, the bandwidth (or reserved bandwidth) of each path, the distance between points of each path (from the start node to the end point) The shortest Hop number to the node) is considered. For example, for the paths p1, p2,..., Pl in this rerouting pattern,
・ Total number of passes: l
-Band of each path (or reserved band): bw _p1 , bw _p2 ,..., Bw _pl
・ Distance between points of each path: dis _p1 , dis _p2 ,..., Dis _pl
From
a = (l, bw _p1 , bw _p2 ,..., bw _pl , dis _p1 , dis _p2 ,..., dis _pl )
It is expressed.

Also, b: the parameter related to the path to be disconnected or connected in the execution of the rerouting procedure pattern is the total number of paths to be disconnected or connected in the execution of the rerouting procedure pattern, the bandwidth (or reserved bandwidth) of each path, The distance between points of each path (the shortest Hop number from the start node to the end node) can be considered. For example, for paths p1, p2,..., Pn that are disconnected or connected in the execution of the pattern of the rerouting procedure,
・ Total number of passes: n
-Band of each path (or reserved band): bw _p1 , bw _p2 , ..., bw _pn
・ Distance between points of each path: dis _p1 , dis _p2 ,..., Dis _pn
From
b = (n, bw _{p 1} , bw _{p 2} ,..., bw _pn , dis _{p 1} , dis _{p 2} ,..., dis _pn )
It is expressed.

Further, c: a parameter related to a path from which traffic is disconnected due to path disconnection in the execution of the rerouting procedure pattern is the total number of paths from which traffic is disconnected due to path disconnection in the execution of this rerouting procedure pattern, each path Bandwidth (or reserved bandwidth) and the distance between points of each path (the shortest Hop number from the start node to the end node) can be considered. For example, for the paths p1, p2,..., Pm in which traffic is disconnected due to path disconnection in the execution of the rerouting procedure pattern,
・ Total number of passes: m
Bandwidth of each path (or reserved bandwidth): bw _p1 , bw _p2 ,..., Bw _pm
・ Distance between points of each path: dis _p1 , dis _p2 ,..., Dis _pm
From
c = (m, bw _p1 , bw _p2 ,..., bw _pm , dis _p1 , dis _p2 ,..., dis _pm )
It is expressed.

  The routing device 1 uses such parameters and penalty functions, so that the cost of the path disconnection and connection when rerouting to the rerouting route, and the cost of the traffic disconnection due to the path disconnection are considered in more detail. Calculation can be realized.

  The routing device 1 according to the present embodiment can be realized by a rerouting program for executing the processing as described above, and the program is stored in a computer-readable storage medium (CD-ROM or the like) and provided. It is possible. It is also possible to provide the program through a network.

It is the figure which showed the example of a structure of the system containing the routing apparatus in embodiment of this invention. It is the figure explaining the flow of each information in the system of FIG. It is the block diagram which showed the structure of the routing apparatus of FIG. It is the flowchart which showed the operation | movement procedure of the routing apparatus of FIG. FIG. 5 is a flowchart showing details of the rerouting calculation process in S408 of FIG. It is the figure which illustrated the network after the rerouting of the path | route of FIG. It is the figure which illustrated the network after the rerouting of the path | route of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Routing apparatus 2 (2A, 2B, 2C, 2D, 2E, 2F) Node 3 Network 4 Network operator terminal 11 Input / output part 12 Processing part 13 Storage part 111 Operation information interface 112 Network information interface 121 Traffic change request information acquisition part 122 network information request unit 123 network information acquisition unit 124 parameter conversion unit 125 rerouting calculation unit 126 rerouting calculation result information reporting unit 131 traffic change request information storage unit 132 network information storage unit 133 parameter conversion policy storage unit 134 rerouting calculation result information storage unit

Claims (6)

For each link connecting each node of the network, the identification information of the node connected by the link and the link information indicating the maximum bandwidth of the link, the topology information of each node in the network, and between the nodes For each established path, a routing device including a storage unit that stores a list indicating link information passing through the path and path information indicating the bandwidth of the path,
Accepting an input of a traffic change request indicating identification information of a start node and an end node of a new path and a bandwidth requested for the new path via the input / output unit,
Referring to the link information, the topology information, and the path information, identify one or more paths that pass through a link on the route of the new path,
A rerouting pattern indicating the reroute destination route of the identified path and the reroute destination route of the other path when rerouting of the other path is necessary along with the rerouting;
Storing the route of the calculated rerouting pattern in the storage unit;
Calculating a pattern of a rerouting procedure when rerouting a path in the network to a route of the calculated rerouting pattern, and storing the pattern in the storage unit;
For each of the calculated rerouting procedure patterns, in the execution of the rerouting procedure pattern, calculate at least one of a path to be disconnected or connected and a path to which traffic is disconnected due to disconnection of the path;
At least one of the accommodated traffic of each path in the route of the calculated rerouting pattern, the path to be disconnected or connected, and the path from which traffic is disconnected due to the disconnection of the path for each pattern of the calculated rerouting procedure To calculate a given objective function using
Reading the path of the rerouting pattern that maximizes the calculated objective function and the pattern of the rerouting procedure to the path of the rerouting pattern from the storage unit, and rerouting the path of the read rerouting pattern and the path of the rerouting pattern A rerouting method comprising outputting a procedure pattern as a rerouting calculation result for the traffic change request. The objective function is defined by the following equation (1):
F = f (a) − {total value of at least one of g (b) and h (c)} (1)
F: Objective function f (a): Function relating to accommodation traffic of each path in the route of the calculated rerouting pattern g (b): Operation procedure amount penalty function in the pattern of the rerouting procedure h (c): of the rerouting procedure Penalty function for occurrence of traffic disconnection due to path disconnection in pattern a: Parameters relating to each path in the route of the rerouting pattern b: Parameters relating to paths to be disconnected or connected in execution of the pattern of the rerouting procedure c: Pattern of the pattern of the rerouting procedure Parameters relating to paths in which traffic is disconnected due to path disconnection in execution The storage unit stores the f (a) and at least one of the g (b) and the h (c). The rerouting method according to claim 1. The routing device
3. The f (a) stored in the storage unit and at least one of the g (b) and the h (c) are changed based on an instruction input from the input / output unit. Rerouting method described in. The routing device
When the maximum value of the calculated objective function is smaller than the value of the objective function calculated using the total bandwidth of each path in the network before setting the new path,
The rerouting method according to any one of claims 1 to 3, wherein a message rejecting the addition of the new path is included in the rerouting calculation result.   5. A rerouting program that causes the routing device that is a computer to execute the rerouting method according to claim 1. For each link connecting each node of the network, the identification information of the node connected by the link and the link information indicating the maximum bandwidth of the link, the topology information of each node in the network, and between the nodes A storage unit that stores, for each established path, a list indicating information of links through which the path passes and path information indicating the bandwidth of the path;
A traffic change request information acquisition unit for receiving an input of a traffic change request indicating identification information of a start node and an end node of a new path and a bandwidth required for the new path, via an input / output unit;
A rerouting calculation unit that calculates a rerouting route of the path and a rerouting procedure to the route;
The rerouting calculation unit
With reference to the link information, the topology information, and the path information,
(1) Specify one or more paths via links on the path of the new path,
(2) calculating a rerouting pattern indicating a rerouting destination route of the identified path and a rerouting destination route of the other path when rerouting of the other path is necessary along with the rerouting;
(3) storing the calculated rerouting pattern path in the storage unit;
(4) calculating a pattern of a rerouting procedure when rerouting a path in the network to a route of the calculated rerouting pattern, and storing the pattern in the storage unit;
(5) For each of the calculated rerouting procedure patterns, calculate at least one of a path to be disconnected or connected and a path to which traffic is disconnected due to the disconnection of the path in the execution of the rerouting procedure pattern;
(6) The accommodated traffic of each path in the route of the calculated rerouting pattern, the path to be disconnected or connected, and the path from which traffic is disconnected due to the disconnection of the path, for each pattern of the calculated rerouting procedure A predetermined objective function is calculated using at least one of
(7) Read the path of the rerouting pattern that maximizes the calculated objective function and the pattern of the rerouting procedure to the path of the rerouting pattern from the storage unit, and read the path of the rerouting pattern and the path of the rerouting pattern A routing apparatus characterized in that a rerouting procedure pattern is output as a rerouting calculation result for the traffic change request.

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