JP5723334B2 - Network topology estimation method and topology estimation apparatus - Google Patents

Description

  The present invention relates to a technique for estimating a network topology, which is a connection relationship between devices constituting a communication network.

  In operating and managing a communication network, it is important to accurately grasp a network topology (hereinafter referred to as topology), which is a connection relationship between devices constituting the communication network. For example, when a failure occurs in the apparatus, the communication path is switched based on the topology. However, if the topology information is not accurate, switching to an incorrect path is performed and communication is interrupted.

  Therefore, as a conventional technique for accurately estimating the topology, a destination and a communication IF (Interface) (hereinafter referred to as a port) such as a routing table and a MAC (Media Access Control) address table referred to when each device transfers data. (For example, Patent Document 1) has been proposed.

  Specifically, from the MAC address table or the like, it is read which device is present ahead of each communication IF of each device, and the same so that data can be transferred without looping for any two devices The connection relationship is estimated based on the condition that the same device exists at the end of the route.

  For example, in the method described in Patent Document 1, the connection relationship between the L2 switches is estimated by reading which device is connected to the end of each port from the MAC address table of each port included in the L2 switch. Assuming that the two L2 switches to be estimated are X and Y, and that the X1 port of X and the Y1 port of Y are connected to each other, the device existing ahead of the X → Y route is From the switch X, the device exists beyond the port X1, and from the switch Y, the device exists beyond the port Y1. If X and Y are connected so that the data does not loop, the same device exists in the same path, so (existing at the port X1 of the switch X) (Apparatus) = (apparatus existing ahead of a port other than port Y1 of switch Y). In the method described in Patent Document 1, paying attention to this condition, for any two L2 switches, a device existing ahead of each port is read from the MAC address table of each port, and the same route mentioned above is read. By examining whether or not the condition that the previous devices match is satisfied, the connection relationship between all the L2 switches is obtained.

JP 2005-348051 A

  However, there is an apparatus that can transfer a packet without referring to destination information, such as determining an output destination port from a source MAC address in a packet, such as SDN (Software Defined Network). Since such a device does not have correspondence information between a destination and a communication IF (port), in the method described in Patent Document 1, which device is connected to a port of each device that is an estimation target is connected. There is a problem that the topology cannot be accurately estimated because it cannot be correctly grasped.

  The present invention has been made in view of the above, and a network topology estimation method and topology capable of estimating a topology even in a communication network including a device that does not have correspondence information between a destination and a communication IF An object is to provide an estimation device.

  In order to achieve the above object, a network topology estimation method and topology estimation system according to the present invention estimate a topology using a packet transmission / reception amount for each communication IF of each device constituting a communication network. .

  Specifically, the network topology estimation method according to the present invention includes a node list in which a list of devices constituting a communication network whose topology is to be estimated is registered, and a communication IF (Interface) included in each of the devices. An IF list in which a list of packet transmission amounts and packet reception amounts is registered is stored in a storage unit, and is a network topology estimation method of a topology estimation device that estimates and outputs a connection relationship between the devices, The topology estimation device increases the value of the variable K representing the number of devices constituting the subnet one by one from 2 to the total number of devices, and refers to the node list to determine the number of K devices. A step of generating all combinations as connection-related determination candidates, and any communication with reference to the IF list for each of the determination candidates A step of generating candidates for all connection forms composed of a set of F, and for each of the connection form candidates, obtain a packet transmission amount and a packet reception amount of each communication IF from the IF list, and The principle 1 that the sum of the packet transmission amounts of all communication IFs included in the candidate is equal to the sum of the packet reception amounts, and the packet transmission amount from each device forming the candidate of the connection form, A step of determining whether or not the principle 2 that the packet reception amount of all other devices forming the form candidate is less than or equal to the principle 1 and the principle 2 is established, and the candidate for the connection form And the step of estimating that there is a connection relationship.

  In this way, even in a communication network configured to include devices that do not have correspondence information between the destination and the communication IF, the topology is determined using the packet transmission / reception amount for each communication IF included in each device constituting the communication network. Can be estimated.

  In the network topology estimation method according to the present invention, the communication IF included in the connection form candidate estimated to have a connection relationship is the communication IF when the subsequent connection form candidate is generated. Excluded from selection.

  By doing so, the number of connection form candidates generated in the step of generating connection form candidates can be appropriately narrowed down.

  Further, according to the present invention, in the network topology estimation method, the determination of the establishment of the principle 1 and the principle 2 for the connection form candidates is based on the fact that the number of the communication IFs included in the connection form candidates is small. It was supposed to be done in order.

  By doing so, it is possible to reduce the amount of processing for determining whether the principle 1 and the principle 2 are established for the connection form candidates.

  Further, according to the present invention, in the network topology estimation method, when the determination result of establishment that is performed first of the principle 1 or the principle 2 is not established, the determination processing of the other principle is performed. It was supposed to be omitted.

  By doing so, it is possible to increase the processing efficiency of the process for determining whether the principle 1 and the principle 2 are established for the connection form candidates.

  The topology estimation apparatus according to the present invention includes a node list in which a list of devices constituting a communication network is registered, and a list of packet transmission amounts and packet reception amounts for each communication IF (Interface) included in each of the devices. Refer to the node list while sequentially increasing the storage unit storing the registered IF list and the value of the variable K representing the number of devices constituting the subnet from 2 to the total number of devices. Then, all combinations of the K devices are generated as connection-related determination candidates, and for each of the determination candidates, all connection form candidates including any set of communication IFs are referred to the IF list. Generating and acquiring the packet transmission amount and packet reception amount of each communication IF from the IF list for each of the connection type candidates, The principle 1 that the total packet transmission amount and the total packet reception amount of all included communication IFs are equal, and the packet transmission amount from each device forming the connection form candidate, If it is determined that Principle 2 is less than the amount of packets received by all other devices that form the candidate, and both Principle 1 and Principle 2 are satisfied, there is a connection relationship with the connection type candidate. And a processing unit that outputs information on the estimated connection relation between the devices.

  In this way, even in a communication network configured to include devices that do not have correspondence information between the destination and the communication IF, the topology is determined using the packet transmission / reception amount for each communication IF included in each device constituting the communication network. Can be estimated.

  In the topology estimation apparatus, the communication IF included in the connection form candidate estimated to have a connection relationship is a selection target of the communication IF when the connection form candidate is generated thereafter. To be excluded.

  By doing so, the number of connection form candidates generated in the step of generating connection form candidates can be appropriately narrowed down.

  Further, according to the present invention, in the topology estimation apparatus, the determination of the establishment of the principle 1 and the principle 2 for the connection form candidates is performed in order from the smallest number of the communication IFs included in the connection form candidates. It was supposed to be.

  By doing so, it is possible to reduce the amount of processing for determining whether the principle 1 and the principle 2 are established for the connection form candidates.

  Further, according to the present invention, in the topology estimation device, when the determination result of establishment that is performed first of the principle 1 or the principle 2 is not established, the determination processing of the other principle is omitted. It was supposed to be.

  By doing so, it is possible to increase the processing efficiency of the process for determining whether the principle 1 and the principle 2 are established for the connection form candidates.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a communication network comprised including the apparatus which does not have correspondence information of a destination and communication IF, the network topology estimation method and topology estimation system which can estimate a topology can be provided. .

It is a functional block diagram of the topology estimation apparatus which concerns on embodiment of this invention. It is the figure which showed the example of data of a node list. It is the figure which showed the example of data of IF list. It is a figure showing an example of data of a judgment candidate list. It is a figure showing an example of data of a connection form list. It is the figure which showed the example of data of the connection list. It is a flowchart of the topology estimation process which concerns on embodiment of this invention. It is a detailed flowchart of the process of a determination candidate list. It is a detailed flowchart of a process of a connection form list. It is the figure which showed the state by which the connection form determined to be connected was registered into the connection list. It is the figure which showed the state from which the communication IF of the connection form determined to be connected was deleted from IF list. It is the figure which illustrated the list of the determination result of a connection form. It is explanatory drawing which shows the connection determination result of all the determination candidates whose number of nodes is 2. It is explanatory drawing which shows the connection determination result of all the determination candidates whose number of nodes is 3. It is the figure which showed the state from which the communication IF of all the connection forms determined connection was deleted from IF list.

  First, the basic concept of the network topology estimation method according to the present invention will be described. The topology estimated by the present invention is a connection relationship between communication IFs (ports) included in each device constituting the communication network. In general, the topology is represented by a graph in which each device constituting the communication network is a node and a connection relation between the devices is a link. Since a group of devices having communication IFs that are connected to each other forms a subnet that is a closed network, topology estimation means grouping nodes that constitute a communication network into a plurality of subnets. I can say that.

When communication is performed normally without packet loops or loss in the estimation target communication network, the following two principles are established in each subnet.
[Principle 1] Inflow traffic and outflow traffic to the subnet are equal.
[Principle 2] Traffic flowing into a subnet from a certain node goes out to a different node in the same subnet.
In the present invention, the topology is estimated by obtaining all nodes belonging to the same subnet from the communication network using the above two principles.

  In general, the outflow / inflow traffic of a node refers to measurement of the packet transmission amount / reception amount of the communication IF of the node. Therefore, the application of Principle 1 and Principle 2 when the packet transmission amount / reception amount of the communication IF of each node is used will be described below.

Here, consider an example where the K nodes N ₁ to N _K to a subnet are connected. It is assumed that at least one communication IF of each node is connected to this subnet, and a total of m (m ≧ K) communication IFs are connected. Now, the set of communication IF of the node _{N 1} which is connected to this subnet and phi _1, Similarly, the node _N 2 to N _K and define those phi ₂ to [phi] _K. In this case, the inflow / outflow traffic to this subnet is the sum of the packet transmission / reception amounts of φ _{1 to} φ _K , respectively. Therefore, in principle 1, phi ₁ using to [phi] _K (phi ₁ to [phi] _K packet transmission amount total) = (phi ₁ to [phi] _K packet reception amount Total) (Equation 1)
It can be expressed as.

Further, the inflow traffic from the node N ₁ to this subnet is the total packet transmission amount of φ ₁ , and according to the principle 2, this traffic is included in the communication IFs of the remaining K−1 nodes other than N _1. The communication IF connected to this subnet, that is, one or more communication IFs in φ _{2 to} φ _K is received. Therefore, for φ _1,
(Phi ₁ packet transmission amount total) ≦ (φ ₂ ~φ _K packet reception amount Total)
Is established. The same applies to the node _N 2 to N _K, in order to satisfy the principle 2,
(Phi _i packet transmission amount _{total) ≦ (φ i φ 1 ~φ} K packet reception amount Total excluding) [i = 1,2, ‥, K] ( Equation 2)
Must be established. Note that the condition that the total packet reception amount similar to this is equal to or less than the other packet transmission amount is derived from Equations 1 and 2 above.

  Therefore, in the topology estimation method according to the present invention, when K nodes satisfy both the above-described Expressions 1 and 2, it is estimated that these node groups have a mutual connection relationship and form a subnet. . That is, a communication network is configured by obtaining a set of all nodes satisfying both of the above-described Expression 1 and Expression 2 using the value of the packet transmission / reception amount of the communication IF of each node to be estimated. Estimate the connection relation, that is, the topology between the nodes.

  Next, the topology estimation procedure of the present invention will be described. Here, a node list in which a list of devices (nodes) to be estimated is registered, a list of communication IFs that each device has, an IF list in which packet transmission amounts / reception amounts for each communication IF are registered, Is given as an input, and the topology of the estimation result is output to a file as a connection list describing all communication IF pairs determined to have a connection relationship.

  The topology estimation procedure will be described below, where n is the number of devices (nodes) registered in the node list and K is a variable representing the number of devices (nodes) forming a subnet.

[Procedure 0]
Set the initial value of K to 2.

[Procedure 1]
All combinations obtained by extracting K nodes from the node list are generated and registered in the determination candidate list.

[Procedure 2]
One combination of nodes registered at the top of the judgment candidate list is selected. When K nodes included in this combination are expressed as N ₁ , N ₂ ,..., N _K , one or more sets of communication IFs φ ₁ are selected from the communication IFs that the node N ₁ has, and similarly All combinations in which φ ₂ ,..., Φ _K are selected from the communication IFs after the node N ₂ are generated as connection forms and registered in the connection form list. At this time, for a node having two or more communication IFs, the number of communication IFs to be selected is initially set to 1 and is increased by 1 in order. Thus, the head of the topology list is registered topology of K communication IF set, the last is the topology consisting of all the communication IF set of N ₁ to N _K is registered Become.

[Procedure 3]
One connection form registered at the top of the connection form list is selected. When a set of communication IFs of each node included in this connection form is represented as φ ₁ , φ ₂ ,..., Φ _K , it is determined whether or not φ ₁ to φ _K are connected to each other by the following procedure. .

[Procedure 3-1]
The total packet transmission amount T _{1 of} φ _{1 and} the total packet reception amount R ₁ are calculated. Similarly, for φ ₂ to φ _K , a total packet transmission amount T _{2 to} T _{K and a} total packet reception amount R _{2 to} R _K are calculated.

[Procedure 3-2]
Using T _{1 to} T _{K and} R _{1 to} R _K , a determination is made as to whether the following determination formula 1 according to principle 1 is satisfied.

  Note that the packet transmission / reception amount changes with time, and there is a possibility that a slight error may occur due to a shift in the collection timing of transmission / reception amount data. For this reason, in determining whether the determination formula 1 is satisfied, the determination is performed while allowing a predetermined error.

[Procedure 3-3]
If the judgment formula 1 is satisfied, it performs establishment determining the following judgment formula 2 according to the principle 2 with an additional _T 1 through T _K and _R 1 to R _K.
T _i ≦ (the sum of _R 1 to R _K except _{R i) [i = 1,2,} ‥, K] ... ( judgment formula 2)
In the same way as described above, it is assumed that the determination is performed while allowing a predetermined error in determining whether the determination formula 2 is satisfied. If determination formula 2 is not satisfied at any of i = 1 to K, the subsequent determinations may be omitted.

[Procedure 3-4]
When both the judgment formula 1 and the judgment formula 2 are established, the combination of the communication IF sets φ ₁ , φ ₂ ,..., Φ _K included in the connection form is registered in the connection list. In addition, communication IF data corresponding to φ ₁ to φ _K is deleted from the IF list.

[Procedure 4]
The connection form for which the determination has been completed from the top of the connection form list is deleted, and steps 3-1 to 3-4 are repeated until the determination for all connection forms is completed.

[Procedure 5]
The determination candidate for which the determination is completed from the top of the determination candidate list is deleted, and steps 2 to 4 are repeated until the determination for all the determination candidates is completed.

[Procedure 6]
Increase the value of K by 1 and repeat steps 1 to 5 until K> n.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings as appropriate.
FIG. 1 is a functional block diagram of a topology estimation apparatus according to an embodiment of the present invention. As shown in FIG. 1, the topology estimation device 1 includes a storage unit 10, a processing unit 20, and an input / output unit 30.

  As shown in FIG. 1, the input / output unit 30 includes an input unit 31 and an output unit 32. Input data of the node list and IF list input from the input device 41 such as a keyboard is received by the input processing unit 21 via the input unit 31 and is registered in the node list and IF list, respectively, and the node list of the storage unit 10. The data is stored in the storage unit 11 and the IF list storage unit 12. The estimated topology is stored as a connection list in the connection list storage unit 15 of the storage unit 10, and the content is output by the output processing unit 29 to the file etc. 42 via the output unit 32.

  As shown in FIG. 1, a storage unit 10 composed of a RAM (Random Access Memory) (not shown) has a node list storage unit 11, an IF list storage unit 12, a determination candidate list storage unit 13, and a connection form list storage. Unit 14 and a connection list storage unit 15 are provided.

  The node list storage unit 11 stores a node list in which a list of nodes subject to topology estimation is registered. FIG. 2 shows an example of data in the node list. In this example, four nodes of node A, node B, node C, and node D are registered as topology estimation targets.

  The IF list storage unit 12 stores a communication IF of each node registered in the node list, and an IF list in which the packet transmission amount and the packet reception amount for each communication IF are registered. One IF list exists for each node. FIG. 3 shows an example of IF list data. In this example, node A has two communication IFs of A1 and A2, node B has two communication IFs of B1 and B2, and node C has C1. The registration state is shown in a case where two communication IFs of C1 and C2 are provided and the node D has one communication IF of D1.

  The determination candidate list storage unit 13 stores a determination candidate list in which a set of nodes that are candidates for connection determination are registered as determination candidates. FIG. 4 is a data example of the determination candidate list, and this example shows a state in which an arbitrary set of two nodes is extracted and registered as a determination candidate from the four nodes A to D.

  The connection form list storage unit 14 stores a connection form list in which connection forms including all possible combinations of communication IFs are registered for each pair of determination candidate nodes registered in the determination candidate list. Here, all possible combinations of communication IFs are all combinations in which one or more communication IFs are selected from each node constituting the determination candidate. FIG. 5 shows an example of data in the connection form list. In this example, a set of all communication IFs corresponding to determination candidates: (A, B) from the same communication IF configuration as the IF list in FIG. Is extracted and registered as a connection form. As in the example of FIG. 5, data is registered in the determination candidate list in ascending order of the number of communication IFs constituting the connection form.

  The connection list storage unit 15 stores a connection list in which connection forms obtained as topology estimation results are registered. In the connection list, a connection form obtained as a result of topology estimation, that is, a set of communication IFs determined to be connected to each other is registered for each line. FIG. 6 shows an example of connection list data. In this example, two connection forms (A1, B2) and (A2, C1, C2, D1) are registered.

  As shown in FIG. 1, an input processing unit 21, a determination candidate generation unit 22, a connection form are included in a processing unit 20 in which each function is realized by a CPU (Central Processing Unit) (not shown) executing a predetermined program. A generation unit 23, a traffic amount calculation unit 24, a determination calculation unit 25, a connection determination unit 26, a first estimation end determination unit 27, a second estimation end determination unit 28, and an output processing unit 29 are provided.

  The input processing unit 21 receives input data of a node list and an IF list input from the input device 41 such as a keyboard via the input unit 31, registers the input data in the node list and the IF list, and stores each of them in the node list of the storage unit 10. The data is stored in the storage unit 11 and the IF list storage unit 12. When the list storage is completed, the initial value of the variable K is set to 2 and the determination candidate generation unit 22 is activated.

  The determination candidate generation unit 22 acquires the node list from the node list storage unit 11, and extracts all sets of nodes that are determination candidates while increasing the number of determination candidate nodes (value of K) one by one in order from 2. Then, it is registered in the determination candidate list and stored in the determination candidate list storage unit 13. In addition, one top determination candidate registered in the determination candidate list is selected and delivered to the connection form generation unit 23. Note that the number of determination candidate nodes is updated by the second estimation end determination unit 28. Here, the combination of all nodes that are candidates for determination is all combinations that select the designated number of nodes from the node group registered in the node list. For example, if four nodes A, B, C, and D are registered, and the number of nodes is 2, (A, B), (A, C), (A , D), (B, C), (B, D), and (C, D) are registered as determination candidates.

  The connection form generation unit 23 receives the determination candidate delivered from the determination candidate generation unit 22, that is, a node set, acquires the IF list of each node included in the node set from the IF list storage unit 12, and can take it A connection form including all communication IF sets is extracted, registered in the connection form list, and stored in the connection form list storage unit 14. At this time, the connection form list is registered so that the connection forms with a small number of communication IFs to be extracted are arranged in order from the list. In addition, one top connection form registered in the connection form list is selected and handed over to the traffic amount calculation unit 24. Here, as examples of all possible combinations of communication IFs, the determination candidates are (A, B), the communication IF of node A is two, A1 and A2, and the communication IF of node B is B1 and B2. And (A1, B1), (A1, B2), (A2, B1), (A2, B2), (A1, A2, B1), (A1, A2, B2), ( A1, B1, B2), (A2, B1, B2), (A1, A2, B1, B2), and these nine connection forms are registered in the connection form list (see FIG. 5). ). In addition, since the communication IF for which the connection relationship has already been determined has been deleted from the IF list, only the communication IF for which the connection relationship has not been determined is the extraction target of the connection form.

  The traffic amount calculation unit 24 calculates the total packet transmission amount and the total packet reception amount in the connection form for each node having each communication IF included in the connection form delivered from the connection form generation unit 23, and the connection form The information is transferred to the determination calculation unit 25 together with the above information.

  The determination calculation unit 25 determines whether or not the determination formula 1 shown in the procedure 3-2 is satisfied and the procedure 3-3 based on the connection form information delivered from the traffic amount calculation unit 24 and the packet transmission / reception amount for each node. The establishment determination of the determination formula 2 shown in FIG. After the determination, the determination results of the determination formula 1 and the determination formula 2 are delivered to the connection determination unit 26 together with the information on the connection form.

  The connection determination unit 26, when both determination formulas are satisfied based on the connection type information delivered from the determination calculation unit 25 and the determination results of the determination formula 1 and the determination formula 2, Are additionally registered in the connection list stored in the connection list storage unit 15. Further, the communication IF data included in the additionally registered connection form is deleted from the IF list stored in the IF list storage unit 12. Furthermore, regardless of whether or not additional registration has been performed, the connection form information is handed over to the first estimation end determination unit 27.

  The first estimation end determination unit 27 deletes the determined connection type information delivered from the connection determination unit 26 from the connection type list stored in the connection type list storage unit 14 and adds another information to the connection type list. If connection form information remains, the connection form generation unit 23 is requested to process the next connection form. If no connection form information remains in the connection form list, the second estimation end determination unit 28 is activated.

  The second estimation end determination unit 28 increments the value of the variable K by 1, and if the value of K is equal to or less than the total number n of nodes to be estimated, the second estimation end determination unit 28 causes the determination candidate generation unit 22 to Request the generation of decision candidates. When the value of K is larger than the total number n of nodes to be estimated, the output processing unit 29 is requested to output the estimated topology.

  The output processing unit 29 is activated by the second estimation end determination unit 28, acquires a connection list representing the topology estimated from the connection list storage unit 15 of the storage unit 10, and stores the contents via the output unit 32 as a file or the like. Output to 42.

  Hereinafter, the topology estimation operation in the present embodiment will be described in detail with reference to flowcharts. FIG. 7 is a flowchart of the topology estimation process executed by the topology estimation apparatus 1 according to this embodiment.

[Step S1]
The input processing unit 21 receives input of node list and IF list data from the input device 41 via the input unit 31, generates a node list and IF list in which the received data is registered, and stores the node list and node list respectively. Are stored in the unit 11 and the IF list storage unit 12.

[Step S2]
The input processing unit 21 sets the number K of determination candidate nodes to be generated to 2 and activates the determination candidate generation unit 22. Thereafter, the second estimation end determination unit 28 increases the value of K by 1 until the value of K exceeds the number of target nodes (the number of nodes registered in the node list), and repeats the processing of steps S3 to S4. Let it run.

[Step S3]
The determination candidate generation unit 22 acquires a node list from the node list storage unit 11, generates a set of all nodes including K nodes as determination candidates, registers them in the determination candidate list, and determines the determination candidate list storage unit 13 To store.

[Step S4]
The determination candidate generation unit 22 performs a determination candidate list process to be described later with reference to FIG. 8 for the generated determination candidate list for the K nodes.

[Step S5]
The second estimation end determination unit 28 returns the process to step S2 to increase the value of K by 1. If the value of K is equal to or less than the number of target nodes, the second estimation end determination unit 28 executes steps S3 to S4. If the number is exceeded, the process proceeds to step S6 to activate the output processing unit 29.

[Step S6]
The output processing unit 29 acquires the connection list stored in the connection list storage unit 15, outputs the connection list to the file etc. 42, and ends the process.

  FIG. 8 is a detailed flowchart of the determination candidate list process executed in step S4 of FIG. In the determination candidate list processing, connection determination of each determination candidate registered in the determination candidate list for the K nodes generated by the determination candidate generation unit 22 is performed.

[Step S11]
The determination candidate generation unit 22 or the first estimation end determination unit 27 acquires the determination candidate list stored in the determination candidate list storage unit 13, and performs the processing from step S12 to step S15 until the determination candidate list becomes empty. Let it run repeatedly. When the determination candidate list becomes empty, the process of the determination candidate list is terminated and the process proceeds to step S5 in FIG.

[Step S12]
The determination candidate generation unit 22 selects one determination candidate registered at the top of the acquired determination candidate list and passes it to the connection form generation unit 23. Since the determination candidates for which processing has been completed are deleted from the determination candidate list, the determination candidates are subsequently delivered one by one in order from the top.

[Step S13]
The connection form generation unit 23 acquires the IF list of each node included in the received (selected) determination candidate from the IF list storage unit 12, and includes all communication IF sets registered in the IF list. Are registered in the connection form list and stored in the connection form list storage unit 14. At this time, since the data of the communication IF whose connection form has already been determined and registered in the connection list has been deleted from the IF list, only combinations of communication IFs whose connection form has not yet been determined are registered in the connection form list. The Rukoto.

[Step S14]
The connection form generation unit 23 executes a connection form list process to be described later with reference to FIG. 9 for the generated connection form list.

[Step S15]
The determination candidate generation unit 22 deletes the determination candidate selected in step S12 from the determination candidate list.

[Step S16]
The first estimation end determination unit 27 returns the process to step S11 and causes the subsequent determination candidates to be processed until the determination candidate list becomes empty.

  FIG. 9 is a detailed flowchart of the connection form list process executed in step S14 of FIG. In the connection form list processing, connection determination is performed for each connection form registered in the connection form list generated by the connection form generation unit 23.

[Step S21]
The connection form generation unit 23 or the first estimation end determination unit 27 acquires the connection form list from the connection form list storage unit 14 and repeatedly executes the processes of steps S22 to S28 until the connection form list becomes empty. When the connection form list becomes empty, the connection form list process is terminated and the process proceeds to step S15 in FIG.

[Step S22]
The connection form generation unit 23 selects one connection form having the smallest number of communication IFs registered at the top of the acquired connection form list, and delivers it to the traffic amount calculation unit 24. Since the connection form that has been processed is deleted from the connection form list, the connection forms are handed over one by one in order from the top.

[Step S23]
The traffic amount calculation unit 24 aggregates transmission / reception traffic of each communication IF included in the delivered connection form for each node.

[Step S24]
The determination calculation unit 25 determines the establishment of Principle 1 (determination formula 1) and Principle 2 (determination formula 2) using the aggregated transmission / reception traffic for each node. At this time, it is determined that Principle 1 is established first, and only if Principle 1 is established, it is determined that Principle 2 is established. If Principle 1 is not established, Principle 2 is established. This determination may be omitted.

[Step S25]
The connection determination unit 26 determines whether or not both the principle 1 and the principle 2 are established. If both the principles are established, the process proceeds to step S26 (Yes side of step S25). On the other hand, if at least one principle is not established, the process proceeds to step S28 (No side of step S25).

[Step S26]
The connection form generation unit 23 registers the connection form selected in step S22 in the connection list.

[Step S27]
The connection form generation unit 23 deletes the data of each communication IF included in the connection form registered in the connection list from the IF list stored in the IF list storage unit 12.

[Step S28]
The connection form generation unit 23 deletes the connection form selected in step S22 from the connection form list.

[Step S29]
The first estimation end determination unit 27 returns the process to step S21 and executes the processes for the subsequent connection forms until the connection form list becomes empty.

  In the following, an example of topology estimation operation in the present embodiment will be described using specific data examples. First, in step S1 of FIG. 7, a node list composed of four nodes A, B, C, and D illustrated in FIG. 2 and an IF list of each node illustrated in FIG. It is assumed that they are generated and stored in the node list storage unit 11 and the IF list storage unit 12, respectively.

  Next, in step S2, the number K of candidate nodes for determination is set to 2, and in step S3, six determination candidates as illustrated in FIG. 4 are registered in the determination candidate list. Next, in step S4, the determination candidate list process is activated, and in step S12 following step S11 in FIG. 8, the determination candidate (A, B) registered at the top of the determination candidate list is selected.

  Next, in step S13, all the connection forms composed of the pairs of communication IFs A1, A2, B1, and B2 registered in the IF list of the node A and the node B in FIG. Nine connection forms as illustrated in FIG. 5 are registered in the connection form list.

  Next, the connection type list process is started in step S14, and in step S22 following step S21 in FIG. 9, the connection type (A1, A1) having the smallest number of communication IFs registered at the top of the connection type list is displayed. B1) is selected.

Next, in step S23, the transmission / reception traffic (total packet transmission amount and total packet reception amount) between the node A and the node B related to the connection form is totaled with reference to the data of the IF list illustrated in FIG. The Here, assuming that the total packet transmission amount of node A is T _A , the total packet reception amount is R _A , the total packet transmission amount of node B is T _B , and the total packet reception amount is R _B , the following is obtained.
T _A = 80 R _A = 60
T _B = 70 R _B = 70

Next, in step S24, it is determined whether Principle 1 and Principle 2 are established. In judgment formula 1 according to principle 1, the total packet transmission amount on the left side is T _A + T _B = 80 + 70 = 150, whereas the total packet reception amount on the right side is R _A + R _B = 60 + 70 = 130. It is determined that Principle 1 is not satisfied. Also, with respect to the determination formula 2 related to the principle 2, since T _A (= 80)> R _B (= 70) and T _B (= 70)> R _A (= 60), it is determined that the principle 2 is not satisfied. Is done.

  Next, in step S25, since neither principle is established, the process branches to the “No” side, and in step S28, the connection form (A1, B1) is deleted from the connection form list of FIG. Returning from step S29 to step S21, processing similar to the above is executed for the next connection form (A1, B2).

This time, the transmission / reception traffic aggregated in step S23 is as follows.
T _A = 80 R _A = 60
T _B = 60 R _B = 80
Therefore, in the determination of step S24, the total packet transmission amount on the left side of the determination formula 1 is T _A + T _B = 80 + 60 = 140, and the total packet reception amount on the right side is R _A + R _B = 60 + 80 = 140. 1 is determined to be established. Also, with respect to the determination formula 2, since T _A (= 80) ≦ R _B (= 80) and T _B (= 60) ≦ R _A (= 60), it is determined that Principle 2 is also established.

  Therefore, in step S25, since both principles are established this time, it is determined that the connection form has a connection relationship, branch to “Yes” side, and in step S26, the connection form (A1, B2). Is registered in the connection list. As a result, the connection list is in the state shown in FIG. Further, in the subsequent step S27, the communication IFs A1 and B2 included in the connection form are deleted from the IF list of FIG. 3, and the IF list becomes the state shown in FIG.

  In the same manner as described above, in the next step S28, the connection form (A1, B2) is deleted from the top of the connection form list, and the process returns from step S29 to step S21. Similar processing is executed.

  FIG. 12 shows a list of the determination results of nine connection forms registered in the connection form list of FIG. 5 including the two connection forms described above. As shown in FIG. 12, it is determined that any connection form other than (A1, B2) has no connection relationship. Note that the communication IF underlined in the connection form column of FIG. 12 has already been deleted from the IF list when the connection form list is generated in step S13 of FIG. The form is not actually registered in the connection form list and is not subject to the judgment for Principle 1 and Principle 2 (see the remarks column). For reference, the judgment results for all connection forms are shown in FIG. Is shown.

  When the connection form list becomes empty by repeating steps S21 to S29 in FIG. 9, the processing of the connection form list of the determination candidates (A, B) is terminated, and the process returns to step S15 in FIG. (A, B) is deleted from the top of the determination candidate list of FIG. 4, and the process returns from the subsequent step S16 to step S11, and the same processing as described above is performed for the remaining five determination candidates.

  FIG. 13 shows a list of determination results for six determination candidates including a set of two nodes (K = 2) registered in the determination candidate list of FIG. 4 including the above-described determination candidates (A, B). Show. As shown in FIG. 13, only the connection forms (A1, B2) in the determination candidates (A, B) are determined to have a connection relationship. In FIG. 13, description of determination results is omitted for connection forms (see remarks column) that are not actually registered in the connection form list and are not subject to the judgment on Principle 1 and Principle 2. “—”.

  When the determination candidate list becomes empty by repeating step S11 to step S16 in FIG. 8, the processing of the determination candidate list of two nodes (K = 2) is terminated, and the process returns from step S5 to step S2 in FIG. The value of K is incremented by 1 and updated to 3, and thereafter the same processing as described above is executed until the value of K is updated to 5.

  FIG. 14 shows a list of determination results for three node (K = 3) determination candidates generated after the IF list is updated as shown in FIG. 11 and all connection forms generated for them. Show. As shown in FIG. 14, only the connection forms (A2, C1, C2, D1) in the determination candidates (A, C, D) are determined to have a connection relationship.

For this connection form (A2, C1, C2, D1), the transmission / reception traffic aggregated in step S23 of FIG. 9 is as follows.
T _A = 70 R _A = 50
T _C = 40 + 30 = 70 R _C = 30 + 50 = 80
T _D = 20 R _D = 30
Therefore, the determination in step S24, the left side packet transmission amount total judgment formula 1 is _{T A + T C + T D} = 70 + 70 + 20 = 160, the right side packet reception total amount of at _{R A + R C + R D} = 50 + 80 + 30 = 160 Therefore, it is determined that Principle 1 is established. Moreover, also about the judgment formula 2, T _A (= 70) ≦ R _C (= 80) + R _D (= 30), T _C (= 70) ≦ R _A (= 50) + R _D (= 30), T _D Since (= 20) ≦ R _A (= 50) + R _C (= 80), it is determined that Principle 2 also holds.

  In step S25 of FIG. 9, since both principles are established, it is determined that the connection form has a connection relationship, branch to “Yes” side, and in step S26, the connection form (A2, C1, C2, D1) is additionally registered in the connection list. As a result, the connection list is in the state shown in FIG. In step S27, the communication IFs A2, C1, C2, and D1 included in the connection form are deleted from the IF list of FIG. 11, and only the B1 is set as the communication IF as shown in FIG. It will be registered. Accordingly, since it is not possible to generate a connection form of three or more nodes in step S13 in FIG. 8, a new connection relationship is not found, and the value of K is finally set to 5 in step S2 in FIG. At the time of the update, the value of K exceeds the number of target nodes (= 4), and in step S6, the contents of the connection list shown in FIG. 6 are output to the file etc. 42, and the process ends.

  By referring to this output, there are two connection relations for the nodes A to D, and the first is that the node A and the node B are connected via the communication IF of A1 and B2. First, it can be seen that the node A, the node C, and the node D are connected to each other through four communication IFs A2, C1, C2, and D1, respectively. It is estimated that the network is composed of a subnet composed of A and Node B and a subnet composed of Node A, Node C, and Node D.

  In the above-described embodiment, the determination candidates and connection forms that have been determined to be deleted are deleted from the determination candidate list and the connection form list, respectively, but a flag column that indicates whether the determination has ended is added to each list. Then, undecided data may be selected with reference to the flag field.

  As described above, according to the present embodiment, even in a communication network such as an SDN that includes a device that does not have correspondence information between a destination and a communication IF, between the devices constituting the communication network. The connection relationship can be estimated, and the topology can be estimated accurately. Therefore, it is possible to improve the quality of operation management of the communication network, such as being able to switch the communication path correctly when a failure occurs in the apparatus.

  This is the end of the description of the embodiment of the present invention. However, the embodiment of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Topology estimation apparatus 10 Memory | storage part 11 Node list preservation | save part 12 IF list preservation | save part 13 Judgment candidate list preservation | save part 14 Connection form list preservation | save part 15 Connection list preservation | save part 20 Processing part 21 Input processing part 22 Judgment candidate production | generation part 23 Connection form production | generation Unit 24 traffic amount calculation unit 25 determination calculation unit 26 connection determination unit 27 first estimation end determination unit 28 second estimation end determination unit 29 output processing unit 30 input / output unit 31 input unit 32 output unit 41 input device 42 file etc.

Claims (8)

A node list in which a list of devices constituting a communication network whose topology is to be estimated is registered; an IF list in which a list of packet transmission amounts and packet reception amounts for each communication IF (Interface) of each of the devices is registered; Is stored in the storage unit, and the network topology estimation method of the topology estimation device that estimates and outputs the connection relation between the devices,
The topology estimation device includes:
While increasing the value of the variable K representing the number of devices constituting the subnet one by one from 2 to the total number of devices,
Generating all combinations of K devices as reference candidates for connection relations with reference to the node list;
For each of the determination candidates, referring to the IF list, generating candidates for all connection forms composed of a set of arbitrary communication IFs;
For each of the connection mode candidates, the packet transmission amount and the packet reception amount of each communication IF are obtained from the IF list, and the packet transmission amount and the packet reception amount of all the communication IFs included in the connection type candidate are obtained. The principle 1 that the total amount is equal, and the packet transmission amount from each device forming the connection form candidate is less than the packet reception amount of all other devices forming the connection form candidate. A step of determining whether or not there is a principle 2 of being,
When both of the principle 1 and the principle 2 are established, estimating a connection relationship for the candidate connection form;
A network topology estimation method characterized by repeating the above. The network topology estimation method according to claim 1,
The communication IF included in the connection form candidate estimated to have a connection relationship is excluded from the selection targets of the communication IF when generating the connection form candidate thereafter. Estimation method. The network topology estimation method according to claim 1,
The determination of establishment of the principle 1 and the principle 2 for the connection form candidates is performed in order from the smallest number of the communication IFs included in the connection form candidates. The network topology estimation method according to claim 1,
The network topology estimation method according to claim 1, wherein the determination process of the other principle is omitted when the determination result of the establishment made before either of the principle 1 or the principle 2 is not established. A topology estimation device for estimating a connection relationship between devices constituting a communication network,
A node list in which a list of devices constituting the communication network is registered, and an IF list in which a list of packet transmission amounts and packet reception amounts for each communication IF (Interface) included in each of the devices are stored. A storage unit;
While increasing the value of the variable K representing the number of devices constituting the subnet one by one from 2 to the total number of devices,
Generating all combinations of K devices as reference candidates for connection relations with reference to the node list;
For each of the determination candidates, refer to the IF list, and generate all connection mode candidates including any set of communication IFs,
For each of the connection mode candidates, the packet transmission amount and the packet reception amount of each communication IF are obtained from the IF list, and the packet transmission amount and the packet reception amount of all the communication IFs included in the connection type candidate are obtained. The principle 1 that the total amount is equal, and the packet transmission amount from each device forming the connection form candidate is less than the packet reception amount of all other devices forming the connection form candidate. Judging the establishment of Principle 2,
When both the principle 1 and the principle 2 are established, the process of estimating that there is a connection relationship for the connection form candidate is repeated,
A processing unit that outputs information on the estimated connection relation between the devices;
A topology estimation apparatus comprising: The topology estimation device according to claim 5,
The topology estimation apparatus characterized in that the communication IF included in the connection form candidate estimated to have a connection relationship is excluded from the selection targets of the communication IF when generating the connection form candidate thereafter. . The topology estimation device according to claim 5,
The topology estimation apparatus according to claim 1, wherein the determination of the establishment of the principle 1 and the principle 2 for the connection form candidates is performed in order from the smallest number of the communication IFs included in the connection form candidates. The topology estimation device according to claim 5,
A topology estimation apparatus characterized in that, when a determination result of establishment that is performed first of either principle 1 or principle 2 is not established, the determination process of the other principle is omitted.

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