Information processing device and information processing method

Abstract

This information processing device receives an input of a parameter of a flow, which is among flows of a VxLAN, for implementing VxLAN OAM. The information processing device, on the basis of the input parameter of the flow, instructs the node of the transmission source of the flow to implement VxLAN OAM Pathtrace with respect on the flow, and receives the implementation results of the Pathtrace. On the basis of the flow via nodes indicated in the received Pathtrace implementation results, the information processing device creates, for each flow, path information indicating the nodes through which the flow passes.

Description

Information processing device and information processing method

[0001] The present invention relates to an information processing device and an information processing method for grasping a flow passing through a specific node in a VxLAN (Virtual eXtensible Local Area Network).

[0002] In network maintenance and operation, it is important to know in advance how many user flows pass through a particular node in order to understand the impact of failures and operation on users.

[0003] JP 2018-129759 A JP 2017-103684 A JP 2016-152480 A

[0004] However, when nodes are connected one-to-many, such as in a datacenter leaf-spine network, the routes from the nodes are generally assigned by hash calculations. This makes it difficult to determine which node the flow from each user passed through. While capturing and analyzing packets is one way to determine the route for each flow, as the number of users, nodes, and ports on each node increases, the number of targets to be captured increases, the amount of data also increases, and the workload required for analysis increases.

[0005] Therefore, an object of the present invention is to solve the above-mentioned problems and reduce the amount of work required to grasp the flow passing through a specific node.

[0006] In order to solve the above-mentioned problems, the present invention is characterized by comprising a parameter input receiving unit that receives input of parameters of a flow that is a target of VxLAN OAM (Operations, Administration, Maintenance) among flows that flow through a VxLAN (Virtual eXtensible Local Area Network); an OAM implementation unit that instructs a source node of the flow to implement VxLAN OAM Pathtrace for the flow based on the input flow parameters and receives the results of the Pathtrace implementation; and a route information creation unit that creates route information indicating the nodes that the flow will pass through for each flow based on the nodes that the flow will pass through that are indicated in the received Pathtrace implementation results.

[0007] According to the present invention, it is possible to reduce the amount of work required to ascertain the flow passing through a specific node.

[0008] FIG. 1 is a diagram illustrating an example of a flow via a network. FIG. 2 is a diagram illustrating an example of a data center NW. FIG. 3 is a diagram illustrating an overview of an information processing device. FIG. 4 is a diagram illustrating an example of a configuration of an information processing device. FIG. 5 is a flowchart illustrating an example of a processing procedure executed by the information processing device. FIG. 6 is a flowchart illustrating an example of a processing procedure executed by the information processing device. FIG. 7 is a diagram illustrating a modified example of the information processing device. FIG. 8 is a flowchart illustrating an example of a processing procedure executed by the information processing device of FIG. 7. FIG. 9 is a flowchart illustrating an example of a process for updating the route information table in S26 of FIG. 8. FIG. 10 is a diagram illustrating details of Pathtrace. FIG. 11 is a diagram illustrating an example of a command for implementing Pathtrace. FIG. 12 is a diagram illustrating an example of a computer that executes an information processing program.

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a description will be given of an embodiment of the present invention with reference to the drawings, but the present invention is not limited to the embodiment.

[0010] [Explanation of Terms and Abbreviations] First, terms and abbreviations used in this embodiment will be explained.

[0011] ・Hash value: A value calculated from original data using a specific calculation procedure, or the calculation procedure itself. If the original data is the same, the same hash value will always be obtained. ・VxLAN: An abbreviation for Virtual eXtensible Local Area Network. A tunneling protocol for building a logical L2 (Layer 2) network on an L3 (Layer 3) network. ・OAM: An abbreviation for Operations, Administration, Maintenance. A general term for operation and management tools, so VxLAN OAM refers to VxLAN operation and management tools. ・Leaf-Spine network: A tree-structured network made up of leaves and spines. For example, it is used as a network within a data center. ・VLAN, vlan-id: An abbreviation for Virtual Local Area Network. A technology for creating virtual LAN segments, and vlan-id is an identifier that represents that segment. ・src-mac: The source MAC address. ・dest-mac: The destination MAC address.・ether-type: A piece of control data written in the header of an Ethernet (registered trademark) frame, which indicates what type of data the frame is carrying. ・ECMP: Abbreviation for Equal Cost Multi Path. A technology that distributes the load by using multiple routes in combination when there are multiple routes with the same cost (number of hops to the destination, etc.). ・MIP: Abbreviation for Maintenance Intermediate Point. A point that relays OAM. ・MEP: Abbreviation for Maintenance End Point. A point that terminates OAM.

[0012] First, how information created by the information processing apparatus of this embodiment (information indicating the route taken by each user flow) is utilized in network management will be described.

[0013] When considering the management of a network (NW) used by many users, understanding the route taken by each user's flow provides the following benefits, for example:

[0014] Advantage 1: When a failure occurs in a specific network device, it is possible to identify the users affected. This makes it easier to identify the extent of the failure when it occurs. Also, if user flows or inflow traffic are concentrated in the area where the failure occurred, maintenance personnel can take measures such as focusing on monitoring that area.

[0015] Advantage 2: Information can be used to make decisions when shutting down network equipment for reasons of the maintenance person (operator), such as software updates for the network equipment. For example, maintenance people can decide to postpone shutting down network equipment that has a high concentration of flows or incoming traffic.

[0016] For example, in the network to be managed shown in Fig. 1, the network device 101 accommodates the traffic of users A and B, and therefore is considered to have a greater impact in the event of a failure than other network devices. Therefore, the maintenance personnel can take measures such as focusing on monitoring the network device 101.

[0017] Furthermore, since the network device 102 can accommodate a smaller amount of traffic than the network device 101, the maintenance person can decide to complete the software update for the network device 102 first.

[0018] Next, a configuration example of a network to be managed by the information processing device of this embodiment will be described with reference to Fig. 2. Here, the network will be described as a data center network that accommodates multiple users (user terminal devices).

[0019] A data center network, for example, is a network consisting of leaves (Leaf #1 to #4) and spines (Spine #1 to #4), with the leaves and spines having a one-to-many connection relationship. When sending a packet, the leaf determines which port to send it from based on a hashed value of the header information. However, the hashing mechanism is generally not made public, and the route between each destination that appears as a result of the hashing is not known until after the system is operational.

[0020] In response to this, the information processing device of this embodiment identifies which NW device (node) the flow of each user passes through as the first step in implementing the above-mentioned network management.

[0021] For example, as shown in Figure 2, assume that each user communicates via L2VPN using VxLAN, and that VxLAN OAM is available. In VxLAN OAM, it is possible to simulate user flows using the inner header's vlan-id, src-mac, dest-mac, and ether-type as parameters. Also, assume that the src-mac and dest-mac for each VLAN are known, and that the ether-type within the network is the same.

[0022] In the following description, the network to be managed by the information processing device is a VxLAN having a leaf and a spine, but is not limited to this as long as it is a VxLAN capable of implementing VxLAN OAM.

[0023] [Overview] Next, an overview of the information processing device will be described using Fig. 3. The information processing device 10 accepts registration of parameters (src-mac and dest-mac) for each VLAN from a maintenance person or the like ((1) Registration of VxLAN OAM parameters). After that, the information processing device 10 transmits an instruction to perform a VxLAN OAM Pathtrace to the start node of the flow in the network (the node corresponding to src-mac) based on the registered parameters ((2)). The start node of the flow is identified by the topology information of the network.

[0024] Thereafter, the start node of the flow that receives the instruction to perform VxLAN OAM Pathtrace from the information processing device 10 performs VxLAN OAM Pathtrace. For example, the start node of the flow transmits a simulated flow based on the parameters indicated in the instruction to perform VxLAN OAM Pathtrace. Packets of this simulated flow follow the same route as packets of the actual user flow that are hashed, and reach the destination node (the node corresponding to dest-mac), which returns the transit nodes of the flow as the results of the Pathtrace execution.

[0025] Thereafter, the information processing device 10 receives the execution result of the VxLAN OAM Pathtrace from the start node of the flow in the network ((3)). Then, the information processing device 10 creates route information that associates the vlan-id, src-mac, dest-mac, and ether-type of the flow with the nodes through which the flow passed (route: source leaf, relay spine, destination leaf) indicated in the execution result of the Pathtrace.

[0026] The information processing device 10 executes the above process for each flow to create route information for each flow. Then, the information processing device 10 creates a route information table (see FIG. 3) that compiles the created route information for each flow.

[0027] Thereafter, when the information processing device 10 receives an instruction from a maintenance person or the like to obtain information on a flow that passes through a specific node ((4)), it searches the route information table for information on the flow that includes the node in its route, and returns the search results ((5)).

[0028] For example, when the information processing device 10 receives an instruction from a maintenance person or the like to acquire information on flows that pass through Spine 2, the information processing device 10 returns information on flows that pass through Spine 2 (the flow information on the second line and the flow information on the Nth line) from the route information table (see FIG. 3) as a search result. This allows the maintenance person to understand the flows that pass through a specific node.

[0029] [Configuration Example] Next, a configuration example of the information processing device 10 will be described with reference to Fig. 4. The information processing device 10 includes, for example, an input / output unit 11, a communication unit 12, a storage unit 13, and a control unit 14.

[0030] The input / output unit 11 is an interface that controls the input and output of various data. For example, the input / output unit 11 receives input of setting information for the information processing device 10 and outputs processing results (e.g., information on flows that pass through specific nodes) by the control unit 14.

[0031] The communication unit 12 is a communication interface for communicating with an external device (for example, a node in the NW) via a network.

[0032] The storage unit 13 stores data, programs, etc. referenced when the control unit 14 executes various processes. The storage unit 13 is realized by a semiconductor memory element such as a random access memory (RAM) or a flash memory, or a storage device such as a hard disk or an optical disk. For example, the storage unit 13 stores topology information of the network. The topology information is information indicating identification information (MAC addresses, etc.) of the nodes (leaves and spines) that make up the network. The storage unit 13 also stores a routing information table (see FIG. 3) created by the control unit 14.

[0033] The route information table is information indicating the nodes (route) through which each flow passes, such as, for example, the VxLAN OAM parameters (vlan-id, src-mac, dest-mac, ether-type) of the flow in association with the route of the flow, as shown in Fig. 3.

[0034] Returning to the description of Fig. 4, the control unit 14 controls the entire information processing device 10. The functions of the control unit 14 are realized, for example, by a CPU (Central Processing Unit) executing a program stored in the storage unit 13.

[0035] The control unit 14 includes a parameter receiving unit 141, an OAM implementation unit 142, a route information creation unit 143, and a search unit 144. A traffic volume receiving unit 145, a traffic volume calculation unit 146, and a traffic information update unit 147, which are indicated by dashed lines, may or may not be provided, and cases where they are provided will be described later.

[0036] The parameter receiving unit 141 receives input of parameters (for example, vlan-id, src-mac, dest-mac, and ether-type) of a flow that is the target of VxLAN OAM.

[0037] Based on the parameters of the received flow, the OAM execution unit 142 instructs the node (leaf) that is the source of the flow in the network to execute a path trace of the VxLAN OAM for the flow. After that, the OAM execution unit 142 receives the execution result of the path trace (the node via which the flow passed) from the node.

[0038] For example, the OAM implementation unit 142 references topology information to identify the leaf (source leaf) corresponding to the src-mac parameter of the flow. The OAM implementation unit 142 then sends a VxLAN OAM path trace execution command to the identified source leaf using the parameters (e.g., the vlan-id, src-mac, dest-mac, and ether-type of the flow). The OAM implementation unit 142 then receives the path trace execution result from the leaf.

[0039] The OAM execution unit 142 executes the above processing for each flow for which the parameter reception unit 141 receives input of parameters.

[0040] When the OAM execution unit 142 receives the Pathtrace execution result, the route information creation unit 143 creates route information indicating the nodes through which the flow passes, based on the nodes through which the flow passes indicated in the Pathtrace execution result.The route information creation unit 143 then adds the created route information to the route information table (see FIG. 3).The route information creation unit 143 executes the above-described route information creation process for each flow.

[0041] If the route information creation unit 143 has already created route information for the same flow in the past, it updates the route information for that flow in the route information table with the newly created route information. This allows the changes to be reflected in the route information table even if the route of the flow in the network is changed.

[0042] The search unit 144 searches the route information table for route information of a flow that passes through a specified node and outputs the search result. For example, when the search unit 144 receives an instruction input of a node to be searched from a network maintenance person or the like, the search unit 144 searches the route information table (see FIG. 3 ) for information of a flow that passes through the node and outputs the search result via the input / output unit 11.

[0043] 5 and 6, an example of a processing procedure executed by the information processing device 10 will be described. First, the parameter receiving unit 141 of the information processing device 10 registers VxLAN OAM parameters (vlan-id, src-mac, dest-mac) (S1).

[0044] After S1, the OAM implementation unit 142 identifies the source leaf corresponding to the above src-mac from the topology information (S2). Then, the OAM implementation unit 142 sends a VxLAN OAM implementation instruction to the source leaf identified in S2 (S3). For example, the OAM implementation unit 142 sends a path trace instruction from src-mac to dest-mac indicated in the VxLAN OAM parameters registered in S1 to the source leaf. Then, the OAM implementation unit 142 receives the VxLAN OAM implementation result (transit node information obtained by implementing the path trace) from the source leaf (S4).

[0045] After S4, the route information creation unit 143 updates the route information table based on the passed-through node information received in S4 (S5). For example, the route information creation unit 143 creates route information for the flow based on the passed-through node information received in S4 and adds it to the route information table.

[0046] The information processing device 10 updates the route information table by performing the above-described processes of S2 to S5 at predetermined intervals.

[0047] Thereafter, when the information processing device 10 receives an input of a node to be searched from a NW maintenance person or the like, it executes the process shown in FIG.

[0048] When the search unit 144 receives an input of a node to be searched from a network maintenance person or the like (S11), it searches the routing information table for information on flows that pass through the node (S12).Then, the search unit 144 outputs the search results of S12 (S13).

[0049] By having the information processing device 10 execute the above process, the maintenance person can obtain information about the flow that passes through a specific node.

[0050] In the case of conventional technology, for example, by capturing packets at ports between the leaf and spine, it is possible to analyze which node the packet was sent from (i.e., which node it passed through) and create a routing information table.

[0051] However, as the number of nodes in the network increases, the number of ports to be captured increases, and as the number of packets in circulation increases, the number of objects to be analyzed increases, etc., the resource situation for creating the routing information table may deteriorate.

[0052] On the other hand, according to the information processing device 10, it is possible to create a route information table if the information on vlan-id, src-mac, and dest-mac in the inner header of the VxLAN OAM is available, so it is not affected by an increase in the number of nodes in the network or an increase in the number of packets.

[0053] Other Embodiments As an extension of the information processing device 10, the information processing device 10 may roughly calculate the traffic volume of each flow based on the traffic volume of each node in the network. In this case, the information processing device 10 will be described as an information processing device 10a.

[0054] [Overview] An overview of the information processing device 10a will be described using Fig. 7. For example, assuming that the conditions of traffic flowing through the NW are the same, when the traffic volume of each node in the NW is given as input data, the information processing device 10a can roughly calculate the traffic volume of a flow passing through a certain node (e.g., node A) using the following formula (1).

[0055] (Traffic volume of node A) / (Number of flows including node A in the route) Sum of nodes through which node A passes...Equation (1)

[0056] Therefore, the information processing device 10a can estimate the traffic volume of each flow by performing the above estimation for each node.The information processing device 10a then reflects the results of the estimation of the traffic volume for each flow in the route information table (see FIG. 7).By performing the above process at predetermined intervals, the information processing device 10a can reflect the latest estimation results (traffic information) of the traffic volume for each flow in the route information table.

[0057] As a result, network maintenance personnel can perform maintenance on each node of the network while taking into consideration the traffic volume of each flow on the network.

[0058] [Configuration Example] Returning to Fig. 4, a configuration example of the information processing device 10a will be described. The same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0059] The information processing device 10 a further includes a traffic volume receiving unit 145 , a traffic volume calculating unit 146 , and a traffic information updating unit 147 .

[0060] The traffic volume receiving unit 145 receives input of the measurement results of the traffic volume of each node in the network. The traffic volume calculating unit 146 roughly estimates the traffic volume for each flow based on the measurement results of the traffic volume of each node and the information in the route information table.

[0061] For example, the traffic volume calculation unit 146 identifies the number of flows passing through each node based on the route information table (see FIG. 7 ). The traffic volume calculation unit 146 then divides the traffic volume of a node by the number of flows passing through that node, adds the result to the number of nodes passed by that flow, and outputs the result as the traffic volume of that flow. The traffic volume calculation unit 146 performs the above process for each flow listed in the route information table.

[0062] The traffic information update unit 147 updates the routing information table using the traffic volume for each flow calculated by the traffic volume calculation unit 146 .

[0063] [Example of Processing Procedure] Next, an example of processing procedure executed by the information processing device 10a will be described with reference to Fig. 8. First, the parameter receiving unit 141 of the information processing device 10a registers VxLAN OAM parameters (vlan-id, src-mac, dest-mac) (S21), similar to S1 in Fig. 5.

[0064] Next, the traffic volume receiving unit 145 registers the traffic volume of each node (S22). Note that S23 to S25 are the same as S2 to S4 in Fig. 5, so the explanation will start from S26 in Fig. 8.

[0065] 8, the information processing device 10a updates the route information table based on the traffic volume of each node registered in S22 (S26). The information processing device 10a executes the above-mentioned processes of S22 to S26 at predetermined intervals.

[0066] Next, the process of updating the route information table in S26 of Fig. 8 will be described in detail with reference to Fig. 9. First, the route information creation unit 143 adds the passed-through node information acquired in S25 to the row of the corresponding parameter in the route information table (S31).

[0067] After S31, the traffic volume calculation unit 146 calculates the traffic volume of each flow based on the traffic volume of the nodes along the route (S32), and the traffic information update unit 147 updates the traffic information in the routing information table (S33).

[0068] By executing the above process, the information processing device 10a can reflect the estimated traffic volume for each flow (traffic information) in the routing information table. As a result, network maintenance personnel can perform maintenance of each node in the network while taking into account the traffic volume of each flow in the network.

[0069] [Details of Pathtrace] The above-mentioned VxLAN OAM Pathtrace is performed, for example, as follows: For example, in the network shown in Fig. 10, a source node of a flow (e.g., Leaf1) measures the path from Leaf1 to Leaf4 by sending an OAM packet (see reference numeral 1001) encapsulated in VxLAN to a remote node (e.g., Leaf4).

[0070] Here, when there are multiple ECMP paths, by setting the parameters (src-mac, dest-mac, ether-type, vlan-id) used to determine the path in the OAM packet, it becomes possible to measure a specific path, and from the measurement results it becomes possible to identify the path of user traffic. Note that the command for performing Pathtrace of VxLAN OAM is, for example, the command shown in Figure 11.

[0071] Here, we will explain an example of measuring the path from Leaf1 to Leaf4 shown in Figure 10. When Leaf1 (MEP) receives the command with the above parameters set, it sends an OAM packet encapsulated in VxLAN to the opposite leaf (Leaf4). The maximum hops of the OAM packet is set to 1 ((1)). This allows the OAM packet to reach the MIP (e.g., Spine2). If the TTL of the received OAM packet is 0, the MIP returns a SpineICMP Time Exceeded message ((2)).

[0072] When Leaf1 receives a reply from the MIP, it resends the OAM packet to the opposite leaf with a maximum hop count of 2 ((3)). When the OAM packet reaches the opposite leaf (Leaf4), Leaf4 processes it according to the flag in the VxLAN header and sends a reply to the opposite leaf (Leaf1) ((4)). After that, when Leaf1 receives a reply from the opposite MEP (Leaf4), it displays the result and ends the process. If the transmission and reception were successful, Leaf4 also displays delay information ((5)).

[0073] [System Configuration, etc.] The components of each unit shown in the figure are conceptual functional units and do not necessarily have to be physically configured as shown. In other words, the specific form of distribution and integration of each device is not limited to that shown, and all or part of them can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc. Furthermore, all or any part of the processing functions performed by each device can be realized by a CPU and a program executed by the CPU, or can be realized as hardware using wired logic.

[0074] Furthermore, among the processes described in the above embodiments, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically using a known method.In addition, the information including the processing procedures, control procedures, specific names, various data and parameters shown in the above documents and drawings can be changed as desired unless otherwise specified.

[0075] [Program] The information processing devices 10 and 10a can be implemented by installing a program (information processing program) as package software or online software on a desired computer. For example, by executing the program on an information processing device, the information processing device can function as the information processing device 10. The information processing device referred to here includes mobile communication terminals such as smartphones, mobile phones, and PHS (Personal Handyphone Systems), as well as terminals such as PDAs (Personal Digital Assistants).

[0076] 12 is a diagram showing an example of a computer that executes an information processing program. The computer 1000 includes, for example, a memory 1010 and a CPU 1020. The computer 1000 also includes a hard disk drive interface 1030, a disk drive interface 1040, a serial port interface 1050, a video adapter 1060, and a network interface 1070. These components are connected by a bus 1080.

[0077] The memory 1010 includes a read-only memory (ROM) 1011 and a random access memory (RAM) 1012. The ROM 1011 stores a boot program such as a basic input / output system (BIOS). The hard disk drive interface 1030 is connected to a hard disk drive 1090. The disk drive interface 1040 is connected to a disk drive 1100. A removable storage medium such as a magnetic disk or optical disk is inserted into the disk drive 1100. The serial port interface 1050 is connected to a mouse 1110 and a keyboard 1120, for example. The video adapter 1060 is connected to a display 1130, for example.

[0078] The hard disk drive 1090 stores, for example, an OS 1091, an application program 1092, a program module 1093, and program data 1094. That is, the programs that define the processes executed by the information processing device 10 are implemented as program modules 1093 in which computer-executable code is written. The program modules 1093 are stored, for example, in the hard disk drive 1090. For example, the program modules 1093 for executing processes similar to those of the functional configuration of the information processing device 10 are stored in the hard disk drive 1090. Note that the hard disk drive 1090 may be replaced with an SSD (Solid State Drive).

[0079] Data used in the processing of the above-described embodiment is stored as program data 1094, for example, in the memory 1010 or the hard disk drive 1090. The CPU 1020 then reads the program module 1093 or the program data 1094 stored in the memory 1010 or the hard disk drive 1090 into the RAM 1012 as necessary and executes them.

[0080] The program module 1093 and program data 1094 may not necessarily be stored in the hard disk drive 1090, but may also be stored in a removable storage medium and read by the CPU 1020 via the disk drive 1100 or the like. Alternatively, the program module 1093 and program data 1094 may be stored in another computer connected via a network (such as a local area network (LAN) or a wide area network (WAN)). The program module 1093 and program data 1094 may then be read by the CPU 1020 from the other computer via the network interface 1070.

[0081] REFERENCE SIGNS LIST 10 Information processing device 11 Input / output unit 12 Communication unit 13 Storage unit 14 Control unit 141 Parameter reception unit 142 OAM implementation unit 143 Route information creation unit 144 Search unit 145 Traffic volume reception unit 146 Traffic volume calculation unit 147 Traffic information update unit

Claims

1. An information processing device comprising: a parameter input receiving unit that receives input of parameters for flows that flow through a VxLAN (Virtual eXtensible Local Area Network) and are subject to VxLAN OAM (Operations, Administration, Maintenance) implementation; an OAM implementation unit that instructs the source node of the flow to implement VxLAN OAM Pathtrace for the flow based on the input flow parameters and receives the results of the Pathtrace implementation; and a route information creation unit that creates route information indicating the nodes that the flow will pass through for each flow based on the nodes that the flow will pass through that are indicated in the received Pathtrace implementation results.

2. The information processing device according to claim 1, further comprising a search unit that searches the route information for each flow for route information of a flow that passes through a specified node, and outputs the search results.

3. The information processing device according to claim 1, further comprising: a traffic volume receiving unit that receives input of the traffic volume for each node of the VxLAN; and a traffic volume calculation unit that, based on the route information for each flow, identifies the number of flows that pass through the node for each node, and outputs the value obtained by dividing the traffic volume of the node by the number of flows that pass through the node and adding the result to the number of nodes that the flow passes through as the traffic volume of the flow.

4. An information processing method executed by an information processing device, comprising: a step of accepting input of parameters of a flow that is a target of VxLAN OAM (Operations, Administration, Maintenance) among flows flowing through a VxLAN (Virtual eXtensible Local Area Network); a step of instructing a source node of the flow to perform VxLAN OAM Pathtrace for the flow based on the input flow parameters and receiving the results of the Pathtrace; and a step of creating route information indicating the nodes that the flow passes through for each flow based on the nodes that the flow passes through that are indicated in the received Pathtrace results.

Images