JP2010193321A - Congestion influence degree evaluation apparatus, congestion influence degree evaluation method and program therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To specify a link having a high possibility of the occurrence of congestion when a plurality of IP links become uncommunicable. <P>SOLUTION: A congestion influence degree evaluation apparatus 10 uses network setting information and fault position information indicative of a fault pattern to create route information 134 indicative of a detour route in the case that a fault of the fault pattern occurs on a network. Next, based on the detour route and alternating traffic information in the network, the traffic volume information 135 of each link in the network is obtained for each fault pattern. The presence/absence of a congestion occurrence link from a result of simulation and a degree of congestion are outputted as a congestion influence degree evaluation result when there is the congestion occurrence link. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for evaluating in advance the occurrence of congestion when the state of a network changes, such as the occurrence of a failure in a network or a change in AC traffic.

  Conventionally, when constructing an IP (Internet Protocol) network, there is a technique for designing a network so that there is a detour route that can continue communication while avoiding the failure location even if a failure occurs in a router or a line. (Refer nonpatent literature 1). In this technology, even if a failure occurs in a router or a line, a resource (for example, a bandwidth of a link connecting nodes) that can relieve all the traffic that was flowing through the failure location is prepared. The communication service can be provided while maintaining the quality without interruption of communication.

  On the other hand, in the IP network, a plurality of link breaks may occur even if there is a single physical failure. For example, when a failure occurs during maintenance of a router or a line, a plurality of link breaks may occur. When a plurality of IP links (lines constituting an IP network) are accommodated in the same optical fiber line, the plurality of IP links are down due to disconnection of the corresponding optical fiber. Further, a plurality of IP links go down due to a failure of a router line card (a line module accommodating a plurality of lines).

  As a method of constructing an IP network so that communication is not interrupted in consideration of such a failure, for example, there is a method in which the active system and the standby system are not accommodated in the same optical fiber line or line card. According to this method, if there is a single physical failure, communication is not interrupted. However, even in such a case, when a plurality of lines are down, there is a possibility that the traffic flowing in the down line is complicatedly bypassed and congestion is generated.

Kamamura et al., “Proposal of Highly Reliable VNT Design Method Considering Transition from Existing Network”, IEICE IEICE Technical Report, NS2007-39, July 2007

  Here, when a plurality of IP links are disconnected, the detour path is often complicated, and there are innumerable combinations of failures, and it is difficult to identify a link that is likely to cause congestion. Met. Therefore, an object of the present invention is to solve the above-described problems and to identify a link that is highly likely to cause congestion even when a plurality of IP links cannot communicate.

  In order to solve the above-described problem, the invention according to claim 1 simulates a link that is highly likely to be congested due to a failure of a plurality of links in the network, and a congestion influence degree that indicates a degree of congestion in the link. Congestion impact assessment device that performs AC traffic information that indicates the amount of traffic flowing between nodes in the network, network topology, link cost for each link in the network, and network settings that indicate the maximum available bandwidth A storage unit that stores information, failure location information indicating one or more failure patterns by a combination of failure links, and the shortest route that bypasses multiple failure links for each failure pattern based on network setting information and failure location information Fault spots that create detour route information indicating the route For each flow of the communication unit and the AC traffic information, a link through the flow is specified in the detour route information created for each failure pattern, and the traffic amount of the flow indicated in the AC traffic information is specified for each of the specified links. The link traffic volume calculation unit for creating link traffic volume information indicating the traffic volume obtained by adding the traffic volume, and the link traffic volume indicated in the link traffic volume information is greater than or equal to the maximum usable bandwidth of the link indicated in the network setting information. When there is a congestion occurrence link, the congestion influence degree calculated by subtracting the value of the maximum available bandwidth related to this congestion occurrence link from the congestion occurrence link, the identification information of the congestion occurrence link, and this congestion Failure pattern that causes the link to occur Characterized in that it comprises a congestion influence degree calculation unit that outputs a congestion impact evaluation results showed.

  The invention according to claim 5 simulates a link that is highly likely to be congested due to a failure of a plurality of links in the network, and a congestion influence degree indicating the degree of congestion in the link, and flows between nodes of the network. AC traffic information indicating the traffic volume of the flow, network topology, network setting information indicating the link cost and maximum available bandwidth for each link in the network, and one or more failure patterns indicated by a combination of fault links Congestion impact assessment device with storage unit for storing failure location information creates detour route information indicating the shortest route that bypasses multiple failure links for each failure pattern based on network setting information and failure location information Steps and flow of exchange traffic information For each, the link through the flow is specified in the detour route information created for each failure pattern, and the traffic amount obtained by adding the traffic amount of the flow indicated in the AC traffic information to each of the specified links. When there is a congested link in which the traffic amount of the link indicated in the link traffic amount information is equal to or greater than the maximum usable bandwidth of the link indicated in the network setting information. The congestion influence level calculated by subtracting the value of the maximum available bandwidth for this congestion occurrence link from the link traffic volume, the congestion occurrence link identification information, and the failure pattern that causes this congestion occurrence link The step of outputting the congestion impact evaluation result shown. It was used as a congestion impact evaluation method according to claim.

  This congestion influence degree evaluation apparatus simulates a detour path when the link group fails for each failure pattern of one or more links in the network. Next, a simulation result of the traffic amount of each link in the network is obtained for each failure pattern based on the simulated detour path and the AC traffic in the network. Then, the presence / absence of congestion and the congestion occurrence link are specified from the simulation result. In addition, a congestion influence degree indicating how much the traffic amount in the congestion occurrence link exceeds the maximum usable bandwidth of the link and a failure pattern in which the congestion occurrence link has occurred are output. In this way, the user of this congestion impact evaluation apparatus can know whether or not congestion has occurred in the network when a failure has occurred even when a plurality of link failures have occurred. Further, when there is congestion, it is possible to know the degree of congestion (congestion influence degree) in the congestion occurrence link and the failure pattern that causes the occurrence of the congestion occurrence link for each congestion occurrence link. Therefore, for example, congestion can be reduced by performing bandwidth enhancement or the like on the congestion occurrence link in advance according to the congestion influence degree.

  The invention according to claim 2 is the failure pattern that causes the congestion influence degree calculation unit in the congestion influence degree evaluation apparatus according to claim 1 to cause the congestion occurrence link to occur as the congestion influence degree evaluation result. And a congestion influence evaluation result indicating the congestion influence degree identification information and the congestion influence degree generated by the failure pattern, and the congestion influence degree in the congestion influence degree is determined for each of the congestion occurrence links. Is a total value obtained by subtracting the value of the maximum available bandwidth of the congestion occurrence link from the traffic amount of the congestion occurrence link.

  By doing in this way, the user of this congestion influence degree evaluation apparatus can know the presence or absence of the congestion in a network for every failure pattern. Also, for each failure pattern, all the congestion-occurring links that occur in that failure pattern, and the total value of the values exceeding the maximum usable bandwidth of each link (that is, the congestion impact on the entire network) Can know. Therefore, for example, the user pays attention to a failure pattern with a large amount of congestion occurrence in the entire network, and performs bandwidth enhancement or the like according to the congestion influence degree in advance for each congestion occurrence link that occurs in the failure pattern. Thus, congestion can be reduced.

  In the invention according to claim 3, when the congestion impact evaluation device according to claim 1 or 2 accepts the input of the identification information of the failed node, the failure node is referred to by referring to the network setting information. And a failure location information creating unit that creates failure location information indicating one or more links that cannot communicate with each other as a failure link.

  By doing in this way, the congestion influence degree evaluation apparatus can output the link congestion occurrence node and the congestion influence degree when the failure of the node is input by inputting the identification information of the failure node.

  In the invention according to claim 4, the congestion influence degree calculation unit in the congestion influence degree evaluation apparatus according to claim 2 or claim 3, in order from the highest congestion influence degree calculated, (1) congestion influence degree, The identification information of the congestion occurrence link and the failure pattern that causes this congestion occurrence link, or (2) the congestion influence level, the failure pattern, and the identification information of all the congestion occurrence links generated by this failure pattern are output. It is characterized by.

  By doing so, the user of the congestion impact evaluation device caused a congestion occurrence link with a high congestion impact degree (that is, a link with a large amount of traffic lost due to congestion) and this congestion occurrence link. It is possible to confirm a failure pattern, a failure pattern having a high congestion influence level of the entire network, a congestion occurrence link generated in the failure pattern, and the like.

  The invention according to claim 6 is a program for causing a congestion influence degree evaluation apparatus, which is a computer, to execute the congestion influence degree evaluation method according to claim 5.

  According to such a program, it is possible to cause a general computer to execute the congestion influence degree evaluation method described in claim 5.

  According to the present invention, even when a plurality of IP links cannot be communicated, a link that is highly likely to cause congestion can be identified. Moreover, the congestion influence degree of the congestion can also be confirmed.

(A) is the figure which showed the structural example of the network, (b) is the figure which showed the structural example of the congestion influence degree evaluation apparatus of this Embodiment. (A) And (b) is the figure which illustrated the route information of this Embodiment. (A) And (b) is the figure which illustrated the link traffic volume information of this Embodiment. It is the flowchart which showed the process procedure of the link traffic amount calculation process in the congestion influence degree evaluation apparatus of this Embodiment. (A) And (b) is the figure which illustrated link traffic volume information of this Embodiment, (c) was created based on the link traffic volume information shown to (a) and (b). It is the figure which illustrated the congestion influence degree evaluation result.

  Hereinafter, modes for carrying out the present invention (hereinafter referred to as “embodiments”) will be described. Here, a case will be described as an example where the congestion influence degree evaluation apparatus according to the present embodiment evaluates the congestion influence degree when a router (node) failure or a link failure occurs in the network shown in FIG. To do. As shown in FIG. 1A, routers R1, R2, R3, R4, and R5 are connected by links. The value appended to the link is the link cost value and is used to determine the route between routers. This link cost is used as an OSPF link cost when the router performs routing using OSPF (Open Shortest Path First).

  Next, the configuration of the congestion impact evaluation device 10 according to the present embodiment will be described with reference to FIG. This congestion influence degree evaluation device 10 reads AC traffic information, network setting information (topology information), and failure location information, and on which link congestion may occur for each assumed failure pattern. To evaluate. And the congestion influence degree in the link (congestion generation link) in which congestion may occur is output as an influence evaluation result. The degree of congestion influence here indicates the degree of congestion caused by detour traffic due to a router or link failure (specifically, the traffic volume of the link minus the maximum available bandwidth).

  Such a congestion impact evaluation apparatus 10 stores AC traffic information 131, network setting information 132, and failure location information 133. In addition, the congestion impact level evaluation apparatus 10 includes a failure simulation unit 121, a link traffic amount calculation unit 122, and a congestion impact level calculation unit 123.

  The AC traffic information 131 stores the amount of traffic of a flow flowing between two arbitrary routers in the network. As illustrated in Table 1 below, the AC traffic information 131 is information in which the identification information of the flow source router and the identification information of the destination router and the traffic amount in the flow are associated with each other. For example, Table 1 shows that 800 Mbps traffic is flowing from the router R1 to the router R2.

  This AC traffic information 131 may be obtained by measuring the traffic volume actually flowing in each router and summing up for each source address and destination address, or by the I / O traffic volume of each router (IF) unit. From this, AC traffic may be estimated. This AC traffic information 131 is referred to when creating link traffic volume information 135 (described later).

  The network setting information 132 is information indicating which router each router in the network is connected to (that is, topology information), the link cost for connecting to the router, the maximum usable bandwidth of the link, and the like. is there. As illustrated in Table 2 below, this network setting information 132 is used for identifying each router identification information and identifying the router (opposite router) to which the router is connected and connecting to the opposite router. Information indicating the identification information of the existing interface, the cost of the link connected to the interface (link cost), the maximum available bandwidth, and the like. The network setting information 132 may include detailed information as included in the router setting information (config).

  The failure location information 133 is information indicating a failure pattern to be subjected to the congestion influence degree evaluation in the congestion influence degree evaluation apparatus 10. As illustrated in Table 3, the failure location information 133 describes a failure location for each failure pattern ID. The failure location is described by the identification information of the link to be failed or the identification information of the routers at both ends of the link. This failure location may be a single link or a plurality of links. Note that when this congestion impact evaluation device 10 performs a congestion impact evaluation of a router failure, all links held by the router are described.

  The failure location information 133 and the network setting information 132 are referred to when the failure simulation unit creates the route information 134.

  The AC traffic information 131, the network setting information 132, and the failure location information 133 are input via an input / output unit (not shown) of the congestion influence degree evaluation apparatus 10, and are RAM (Random Access Memory), ROM (Read Only). It is stored in a storage unit such as a memory (HDD), a hard disk drive (HDD), or a flash memory.

  The failure simulation unit 121 creates route information 134 indicating a detour route when a failure of the failure pattern occurs for each failure pattern indicated by the failure location information 133 in the network indicated by the network setting information 132. Note that the failure simulation unit 121 creates route information 134 (route information 134 at normal time) as shown in FIG. 2A, for example, unless a failure location is specified. On the other hand, for example, when the failure location (failure link) is “R1-R2” and “R1-R3”, as shown in FIG. 2B, detouring of “R1-R2” and “R1-R3” is performed. Route information 134 including the route (the detour route “R1 → R5 → R4 → R3 → R2” of “R1-R2”, the detour route “R1 → R5 → R4 → R3” of “R1-R3”) is created. The created route information 134 is stored in the storage unit of the congestion impact evaluation device 10. Note that the detour route calculated by the failure simulation unit 121 is, for example, a route with the minimum cost by OSPF or the like.

  The link traffic amount calculation unit 122 in FIG. 1B refers to the path information 134 for each flow indicated in the AC traffic information 131, and identifies a link through which a failure occurs indicated in the failure pattern. Then, link traffic volume information 135 is created by adding the traffic volume of the flow indicated in the AC traffic information 131 to each of the identified links. That is, when communication is performed through the route indicated by the route information 134 and the traffic amount indicated by the AC traffic information 131 flows between routers, the amount of traffic flowing through each link is calculated, and the calculation result Is recorded in the link traffic volume information 135. The link traffic volume information 135 is created for each failure pattern and stored in the storage unit of the congestion impact evaluation device 10. Details of the link traffic amount calculation processing will be described later using a flowchart.

  As illustrated in FIGS. 3A and 3B, the link traffic volume information 135 includes, for each link ID (link identification information) of a link in the network, identification information and traffic of routers at both ends of the link. The quantity etc. are shown. Normally, in an IP network, traffic is bidirectional, but the traffic volume may vary depending on the direction. For example, information for one line of the link traffic volume information 135 shown in FIGS. Indicates one-way traffic. As the traffic amount of the failure link (for example, “R1-R3”), information such as “failure” may be written as illustrated in FIG. 3B, or “0” may be written.

  The congestion influence degree calculation unit 123 determines whether or not the link indicated in the link traffic amount information 135 includes a link (congestion occurrence link) having a traffic amount equal to or greater than the maximum usable bandwidth of the link indicated in the network setting information 132. to decide. Then, when there is a congestion occurrence link, the congestion influence degree calculation unit 123 subtracts a value obtained by subtracting the value of the maximum available bandwidth related to this congestion occurrence link (described in the network setting information 132) from the traffic amount of the congestion occurrence link. Calculated as congestion impact. Then, a congestion influence evaluation result indicating the identification information of the congestion occurrence link, the congestion influence degree in the congestion occurrence link, and the failure pattern causing the congestion in the link is created. The created congestion influence degree evaluation result is stored in a predetermined area of the storage unit or output via an input / output unit (not shown).

  As illustrated in Table 4, the congestion influence degree evaluation results may be ranked and arranged in descending order of the influence traffic amount (congestion influence degree). By doing in this way, the user of this congestion influence degree evaluation apparatus 10 is which link has a high influence traffic amount (congestion influence degree) among the congestion occurrence links, and further causes the link to generate congestion. It is possible to know what kind of failure pattern the cause failure pattern is.

  The failure simulation unit 121, the link traffic amount calculation unit 122, and the congestion influence degree calculation unit 123 described above are realized by a program execution process by a CPU (Central Processing Unit) included in the congestion influence degree evaluation apparatus 10, a dedicated circuit, or the like. Is done. When the congestion influence degree evaluation device 10 is realized by a program execution process, a program for realizing the function of the congestion influence degree evaluation device 10 is stored in the storage unit. Note that the program may be provided by being stored in a computer-readable recording medium (such as a CD-ROM).

  Here, the processing procedure of the link traffic amount calculation unit 122 of the congestion impact evaluation apparatus 10 will be described with reference to Table 1 and FIG. Here, a case where the assumed failure pattern is a link failure of “R1-R2” and “R1-R3” will be described as an example. First, the link traffic amount calculation unit 122 in FIG. 1B reads out information of one flow from the AC traffic information 131 (see Table 1) (S1). For example, the link traffic amount calculation unit 122 reads the information of the transmission source “R1”, the destination “R2”, and the traffic amount “800 Mbps” from the AC traffic information 131 shown in Table 1.

  Then, the link traffic amount calculation unit 122 searches the route information 134 for a route corresponding to the source router (S) of the read flow information and the destination router (D) (S2). For example, it corresponds to the transmission source “R1” and the destination “R2” from the path information 134 shown in FIG. 2B (that is, the path information when the failure location is “R1-R2” and “R1-R3”). “R1 → R5 → R4 → R3 → R2” is searched as a route.

  Next, the link traffic amount calculation unit 122 traces each link on the route from the transmission source to the destination, and adds the traffic amount read from the AC traffic information 131 to each link. . That is, the AC traffic information 131 indicates the traffic volume of the flow from the source router to the destination router, but it is not known what route the flow actually follows. Therefore, the route for each flow is read from the route information 134, and the traffic amount read from the AC traffic information 131 is added to each link on the route to obtain the traffic amount of each link.

  That is, the link traffic amount calculation unit 122 executes the following processing, assuming that S = source router and R = currently focused router (S3). First, when the link traffic amount calculation unit 122 confirms that the router R currently focused on is not the destination router D (No in S4), the router R currently focused on in the link traffic amount information 135 → The traffic amount of the flow read from the AC traffic information 131 is added as the traffic amount of the link connecting this router R to the next router, and the link traffic amount information 135 is updated (S6). Then, the link traffic amount calculation unit 122 advances R by one (S7). That is, the link traffic amount calculation unit 122 proceeds to the process for the next link. Then, the process returns to S4. In S4, the link traffic amount calculation unit 122 confirms that the router R currently focused on is the destination router D (Yes in S4), and if there is information on the flow that has not yet been read in the AC traffic information 131. (Yes in S5), the process returns to S1. On the other hand, if the information of all the flows of the AC traffic information 131 has been read (No in S5), the process is terminated as it is.

  For example, the link traffic amount calculation unit 122 transmits the traffic amount of the flow from the source “R1” to the destination “R2” read from the AC traffic information 131 for each link in the route “R1 → R5 → R4 → R3 → R2”. “800 Mbps” is added, and the link traffic amount information 135 is updated. Further, the link traffic amount calculation unit 122 reads out information of the transmission source “R1”, the destination “R3”, and the traffic amount “400 Mbps” from the AC traffic information 131 (see Table 1). When the link traffic amount calculation unit 122 reads the route from the transmission source “R1” to the destination “R3” (“R1 → R5 → R4 → R3”) from the route information 134, the link traffic amount information 135 , “400 Mbps” is added to the traffic amount for each link in the route “R1 → R5 → R4 → R3”. As a result, the traffic volume of “R1 → R5”, “R5 → R4”, “R4 → R3” in the link traffic volume information 135 is “800 Mbps + 400 Mbps = 1100 Mbps”, and the traffic volume of “R3 → R2” is “800 Mbps”. It becomes. The link traffic volume calculation unit 122 executes the above processing for information regarding all the flows indicated in the AC traffic information 131 to create link traffic volume information 135.

  Thereafter, the congestion impact level calculation unit 123 creates an impact level evaluation result with reference to the link traffic volume information 135 and the information on the maximum usable bandwidth of each link indicated in the network setting information 132. For example, in the link traffic volume information 135 shown in FIG. 3B, the link exceeding the maximum available bandwidth shown in the network setting information 132 (congestion link) is “R4 → R3”, and the maximum of this link When the available bandwidth is “1000 Mbps”, a value “200 Mbps” obtained by subtracting the maximum available bandwidth “1000 Mbps” from the traffic amount “1200 Mbps” of the link “R4 → R3” is written as the congestion influence level. Here, if there are a plurality of congestion occurrence link costs, the congestion influence degree calculation unit 123 may rank and display the congestion influence degrees by paying attention to the congestion influence degrees of the plurality of congestion occurrence links.

  According to the congestion influence degree evaluation apparatus 10 described above, it is possible to estimate a link, a congestion influence degree, and the like that may cause congestion due to the failure by inputting the failure part.

  If a plurality of failure patterns are described in the failure location information 133, the link traffic amount calculation unit 122 creates link traffic amount information 135 for each failure pattern. For example, the link traffic amount calculation unit 122 displays the link traffic amount information 135 in the case of the failure locations “R1-R2” and “R1-R3” illustrated in FIG. 5A and the failure illustrated in FIG. The link traffic volume information 135 for the location “R4-R3” is created. Then, the congestion influence degree calculation unit 123 creates a congestion influence degree evaluation result shown in FIG. 5C based on the link traffic amount information 135. Based on the result of the congestion influence degree evaluation, the user of the congestion influence degree evaluation apparatus 10 can confirm the congestion occurrence link and the influence traffic amount (congestion influence degree) in the congestion occurrence link for a plurality of failure patterns. Further, in this congestion influence degree evaluation result, as exemplified in FIG. 5C, the results may be ranked and displayed in descending order of the influence traffic amount. That is, in the link traffic volume information 135 shown in FIG. 5A, if the traffic volume of the link “R4 → R3” is “1200 Mbps” and the maximum bandwidth of the link is “1000 Mbps”, this link is congested. It is a generated link. Further, the influence traffic amount of this link is “200 Mbps”. Also, in the link traffic volume information 135 shown in FIG. 5B, if the traffic volume of the link “R1 → R3” is “1100 Mbps” and the maximum bandwidth used for this link is “800 Mbps”, this link is also congested. It is a generated link. The influence traffic amount of this link is “300 Mbps”. Therefore, the congestion influence degree evaluation result shown in FIG. 5C shows the links “R1 → R3” and “R4 → R3” which are congestion occurrence links, and the influence traffic amount of each link, and this influence traffic. The ranking of the link “R1 → R3” with the largest amount is “1”, and the ranking of the link “R4 → R3” is “2”.

  Further, the congestion influence degree evaluation result may be ranked by evaluating the influence (influence traffic amount) for each failure pattern. For example, for each failure pattern, the total value of the influence traffic amount of each link determined to be a congestion occurrence link in the failure pattern is calculated as the influence traffic amount of the failure pattern. That is, the influence traffic amount of the entire network in the failure pattern is calculated. Then, as illustrated in Table 5 below, the congestion influence evaluation is performed on the failure pattern, the calculated influence traffic amount, and one or more congestion occurrence links in the failure pattern in descending order of the calculated influence traffic amount. Display in the result. According to the congestion influence degree evaluation result, the user of the congestion influence degree evaluation apparatus 10 can check which failure pattern among the assumed failure patterns affects the entire network.

  In the above-described embodiment, the failure location information input to the congestion impact evaluation device 10 has been described as an example where it is described by a failure link. However, the present invention is not limited to this. For example, the failure node identification information may be described in the input failure location information. In this case, the congestion impact evaluation device 10 refers to the input failure location information and the network setting information 132 to identify the link held by the router. That is, the link that becomes a failed link when the router fails is specified. Then, the identification information of the specified failure link group is written in the failure location information 133 as a failure pattern when the router fails. Then, the congestion influence degree evaluation device 10 creates a congestion influence degree evaluation result by the same procedure. That is, the failure simulation unit 121 calculates a detour route of a link that cannot be communicated due to a failure of the node, and creates route information 134 based on the result. Then, the link traffic amount calculation unit 122 creates link traffic amount information 135 using the route information 134 and the AC traffic information 131, and the congestion influence degree calculation unit 123 creates a congestion influence degree evaluation result, Output. By doing in this way, the congestion influence degree evaluation apparatus 10 can estimate which link will generate congestion and which congestion will occur when which router in the network fails.

DESCRIPTION OF SYMBOLS 10 Congestion influence evaluation apparatus 121 Failure simulation part 122 Link traffic amount calculation part 123 Congestion influence degree calculation part 131 AC traffic information 132 Network setting information 133 Fault location information 134 Path information 135 Link traffic quantity information

Claims (6)

A congestion impact evaluation device that simulates a link that is likely to cause congestion due to a failure of a plurality of links in the network and a congestion impact that indicates the degree of congestion in the link,
AC traffic information indicating the amount of traffic flowing between the nodes of the network, network configuration information indicating the topology of the network, link cost and maximum available bandwidth for each link in the network, and one or more failure patterns A storage unit that stores failure location information indicating a combination of failed links and link information indicating the maximum usable bandwidth of each link for each link in the network;
Based on the network setting information and failure location information, for each failure pattern, a failure simulation unit that creates detour route information indicating the shortest route that bypasses the plurality of failure links;
For each flow of the AC traffic information, a link through the flow is specified in the detour route information created for each failure pattern, and the traffic amount of the flow indicated in the AC traffic information is specified for each of the specified links. A link traffic amount calculation unit for creating link traffic amount information indicating the added traffic amount;
When there is a congestion-occurring link whose link traffic amount indicated in the link traffic amount information is equal to or greater than the maximum usable bandwidth of the link indicated in the network setting information, this congestion occurrence is determined from the traffic amount of the congestion-occurring link. Congestion influence evaluation indicating the congestion influence degree calculated by subtracting the value of the maximum usable bandwidth related to the link, the identification information of the congestion occurrence link, and the failure pattern causing the occurrence of the congestion occurrence link A congestion impact calculator that outputs the results;
A congestion influence degree evaluation apparatus comprising: The congestion influence degree calculation unit, as the congestion influence degree evaluation result,
Output the failure impact evaluation result indicating the failure pattern that causes the occurrence of the congestion occurrence link, the identification information of all the congestion occurrence links generated by the failure pattern, and the congestion impact level,
The congestion influence degree in the congestion influence degree evaluation is a total value of values obtained by subtracting the maximum usable bandwidth value of the congestion occurrence link from the traffic amount of the congestion occurrence link for each of the congestion occurrence links. The congestion influence degree evaluation apparatus according to claim 1, wherein   When receiving the input of the identification information of the failed node, the failure location information is created by referring to the network setting information and indicating one or more links that cannot communicate when the failed node fails as a failed link The congestion influence degree evaluation apparatus according to claim 1, further comprising a failure location information creation unit that performs the operation. The congestion impact calculation unit
In order from the highest congestion influence degree calculated, (1) the congestion influence degree, the identification information of the congestion occurrence link and the failure pattern causing the occurrence of the congestion occurrence link, or (2) the congestion influence. 4. The congestion influence degree evaluation apparatus according to claim 2, wherein the failure pattern and identification information of all congestion occurrence links generated by the failure pattern are output. An exchange showing the amount of traffic flowing between the nodes of the network by simulating a link that is likely to cause congestion due to the failure of multiple links in the network and the congestion influence level indicating the degree of congestion in the link Traffic information; network configuration information indicating the topology of the network; link cost and maximum available bandwidth for each link in the network; failure location information indicating one or more failure patterns by a combination of failure links; and the network For each link, a congestion impact evaluation device comprising a storage unit that stores link information indicating the maximum usable bandwidth of the link,
Based on the network setting information and failure location information, for each failure pattern, creating detour route information indicating the shortest route that bypasses the plurality of failure links;
For each flow of the AC traffic information, a link through the flow is specified in the detour route information created for each failure pattern, and the traffic amount of the flow indicated in the AC traffic information is specified for each of the specified links. Creating link traffic volume information indicating the added traffic volume;
When there is a congestion-occurring link whose link traffic amount indicated in the link traffic amount information is equal to or greater than the maximum usable bandwidth of the link indicated in the network setting information, this congestion occurrence is determined from the traffic amount of the congestion-occurring link. Congestion influence evaluation indicating the congestion influence degree calculated by subtracting the value of the maximum usable bandwidth related to the link, the identification information of the congestion occurrence link, and the failure pattern causing the occurrence of the congestion occurrence link And a step of outputting a result.   A non-transitory computer-readable storage medium storing a program for causing a congestion influence degree evaluation apparatus, which is a computer, to execute the congestion influence degree evaluation method according to claim 5.

Images