JP7529047B2 - Simulation device, traffic simulation system, simulation method and program - Google Patents

Description

The present disclosure relates to traffic simulation in a communication network.

In order to predict packet loss that will occur within a communication network, simulations that vary the traffic type and volume are commonly performed. However, when conducting simulations that assume the high-speed, high-capacity communication networks of today, there is a problem that the simulation time becomes long because it is necessary to measure extremely small loss rates while simulating an extremely large number of communication packets.

In the prior art, a method has been proposed to shorten the time required for a simulation by terminating the simulation when the loss rate can be determined to be statistically valid. However, when simulating a high-speed, large-capacity communication network of the 100 Gbps class, it is necessary to simulate a large number of packets, which poses the problem of requiring a large amount of computational resources and lengthening the time required for the simulation. In addition, traffic simulation generally employs discrete event simulation, in which the simulation is performed by advancing time little by little, which also poses the problem of difficulty in parallel execution.

JP 2013-192005 A JP 2017-112549 A

The present disclosure aims to enable the simulation of high-speed, high-capacity communication networks.

A simulation device according to the present disclosure includes:
a packet regenerator for generating traffic based on the packet capture file;
A packet capture that captures packets based on a packet capture file;
A communication device connected to the packet regenerator and the packet capture device;
Connected to
generating a generation condition file in the form of a packet capture file that defines traffic to be generated in the packet regenerator;
generating a capture condition file in the form of a packet capture file that defines conditions for capturing the packet;
generating traffic by causing the packet regenerator to execute the generation condition file;
The packet capture is performed by executing the capture condition file on the packet capture.

The simulation method according to the present disclosure includes:
a packet regenerator for generating traffic based on the packet capture file;
A packet capture that captures packets based on a packet capture file;
A communication device connected to the packet regenerator and the packet capture device;
A simulation method executed by a simulation device connected to
The simulation device,
generating a generation condition file in the form of a packet capture file that defines traffic to be generated in the packet regenerator;
generating a capture condition file in the form of a packet capture file that defines conditions for capturing the packet;
generating traffic by causing the packet regenerator to execute the generation condition file;
The packet capture is performed by executing the capture condition file on the packet capture.

A traffic simulation system according to the present disclosure includes:
A simulation device according to the present disclosure;
the packet regenerator for generating traffic based on a packet capture file;
The packet capture is configured to capture packets based on a packet capture file;
Equipped with.

The program of the present disclosure is a program for realizing each functional unit of the device of the present disclosure as a computer, and is a program for causing a computer to execute each step of the communication method performed by the device of the present disclosure.

This disclosure makes it possible to simulate high-speed, high-capacity communication networks.

1 illustrates an example of a system configuration according to the present disclosure. An example of a computer 91 is shown. 1 illustrates an example of a packet processing flow of the present disclosure. 1 illustrates an example of a network topology. 1 shows an example of the traffic occurrence information unit 13. 11 shows an example of the packet capture DB 23 upon completion of step S01. An example of traffic stored in Client4.pcapng is shown below. An example of the packet capture DB when the S02-01 process for router #1 is completed is shown. 1 shows an example of an FIB to be set in a communication device. 13 shows an example of queue information to be set in the communication device. An example of the packet capture DB when the process S02-04 for router #1 is completed is shown. An example of the packet capture DB when the process of step S02-01 for router #3 is completed is shown. 1 shows an example of an FIB to be set in a communication device. 13 shows an example of queue information to be set in the communication device. An example of the packet capture DB when the process S02-04 for router #3 is completed is shown. 1 shows an example of a packet capture DB. 11 shows an example of step S02 in the second embodiment. 1 shows an example of an expected packet capture in a packet capture DB. 1 shows an example of traffic fluctuations using assumed packet capture. 1 shows an example of traffic fluctuations using assumed packet capture.

Below, the embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Note that components with the same reference numerals in this specification and drawings are considered to be identical to each other.

First Embodiment
1 shows an example of a system configuration according to the present disclosure. The system according to the present disclosure includes a computer 91, a packet regenerator 92, and a packet capture device 93. A communication device 94 has a plurality of ports and is connected to the packet regenerator 92 and the packet capture device 93.

The communication device 94 can set a forwarding information base (FIB), queue information, QoS settings, etc. based on instructions from the communication device setting unit 16 of the computer 91. Specifically, an OpenFlow switch that can externally control the setting of the FIB is assumed.

The packet replay device 92 is a device that reads a packet capture file (such as a pcap file) and plays it back as is. It is generally called a packet replayer.
The packet capture 93 is a device that captures incoming packets and stores them as a file (such as a pcap file).

Figure 2 shows an example of a computer 91. The computer 91 functions as a simulation device and includes a simulation control unit 11, a traffic occurrence simulation unit 12, a traffic occurrence information unit 13, a network topology simulation unit 14, a network topology information unit 15, a communication device setting unit 16, a packet replay instruction unit 17, a packet replay result acquisition unit 21, a packet capture file control unit 22, a packet capture DB 23, a packet capture analysis unit 24, and a simulation result DB 25. The computer 91 of the present disclosure can also be realized by a computer and a program, and the program can be recorded on a recording medium or provided via a network.

The simulation control unit 11 controls each functional unit of the simulation device.
The traffic occurrence simulation unit 12 performs a simulation of traffic occurrence based on instructions from the simulation control unit 11. Specifically, it simulates the occurrence of calls and the continuation/termination of calls by Monte Carlo simulation under predetermined distribution conditions such as a Poisson process.
The traffic occurrence information unit 13 is a memory for storing the results of the traffic occurrence simulation in the traffic occurrence simulation unit 12 .
The network topology simulation unit 14 performs a simulation of a network topology based on an instruction from the simulation control unit 11. Specifically, the network topology is generated randomly or fixedly.
The network topology information unit 15 is a memory that holds the results of a network topology simulation.
The communication device setting unit 16 sets the communication device 94 based on the network topology information in accordance with an instruction from the simulation supervision unit 11. The information to be set is assumed to include FIB, queue information, QoS settings, and the like.
Based on instructions from the simulation control unit 11, the packet replay instruction unit 17 reads a pcap file (generation condition file) from the packet capture file DB 23, registers it in the packet replay device 92, and plays it back at any timing.
The packet replay result acquisition unit 21 acquires the packet capture file acquired by the packet capture 93, and registers it in the packet capture DB 23. As a result, the capture result file captured by the packet capture 93 is stored in the packet capture DB 23.
The packet capture file control unit 22 generates, edits, and synthesizes a packet capture file based on instructions from the simulation supervision unit 11. This generates a generation condition file that defines the traffic to be generated in the packet regenerator 92, and a capture condition file that defines the conditions for capturing in the packet capture 93. Assumed functions include libraries such as editcap and mergecap in Wireshark and scapy in Python.
The packet capture DB 23 is a database that stores packet capture files, which include a generation condition file, a capture condition file, and a capture result file.
Based on instructions from the simulation control unit 11 , the packet capture analysis unit 24 analyzes the values in the packet capture DB 23 to obtain simulation results, and stores the results in a simulation result DB 25 .

An example of a packet processing flow according to the present disclosure is shown in Fig. 3. The packet processing flow according to the present disclosure includes steps S01, S02, and S03 in this order.
In step S01, the packet capture file control unit 22 generates a packet capture file indicating the traffic generated from each transmitting terminal over the entire simulation time based on the description in the traffic occurrence information unit 13, and stores the file in the packet capture DB .
In step S02, routers are selected starting from those closest to the transmitting terminal, and the process described later is executed for each router in sequence.
In step S03, the packet capture analysis unit 24 generates a simulation result using the packet capture file held in the packet capture DB 23, and stores the result in the simulation result DB.

In step S02, the following processes are executed in sequence.
Step S02-01: The packet capture file control unit 22 generates packet capture files, which are input to the router, over the entire simulation time using the network topology information stored in the network topology information unit 15 and the packet capture files held in the packet capture DB 23, and stores them in the packet capture DB 23. As a result, a generation condition file for generating traffic in each packet regenerator 92 is stored in the packet capture DB 23.
Step S02-02: The communication device setting unit 16 registers information about the selected router in the communication device 94 based on the network topology information unit 15. For example, when router #1 is selected, the router #1 is set so that the router #1 receives traffic from terminals #1 to #3 and transmits it to router #3.
Step S02-03: The packet replay instruction unit 17 replays the packet capture file generated in step S02-01 from the packet replay device 92. At this time, the packet replay device 17 causes each packet capture device 93 to execute a capture condition file that defines the capture conditions. As a result, the packet capture device 93 captures the traffic sent from the communication device 94.
Step S02-04: The packet replay result acquisition unit 21 stores in the packet capture DB 23 the data stored by the packet capture 93 in step S02-03.

An example of a simulation in the network topology shown in Figure 4 is shown. In Figure 4, terminals #1 to #3 are connected to router #1, terminal #4 is connected to router #2, terminals 5 to #8 are connected to router #4, routers #1 and #2 are connected to router #3, and routers #3 and #4 are connected. In the figure, ms indicates the communication delay time that occurs between links. All link speeds are 10 Gbps. The network topology shown in this figure is an example of an embodiment of the present disclosure, and the network topology and format of the present disclosure are not important. For example, a format such as YAML may be used in which links are named and saved.

Figure 5 shows an example of the traffic occurrence information unit 13. The source and destination indicate the addresses #1 to #8 shown in Figure 4, respectively. In this embodiment, an example is shown in which the time, duration, and traffic content are stored, which are transmitted from terminals #1 to #4 shown in Figure 4 to terminals 5 to #8.

The results of the simulation by the traffic generation simulation unit 12 indicate the occurrence and continuation/end of calls. The simulation method for obtaining the above information is not a special method, and may involve, for example, obtaining the time of call occurrence and duration using random numbers generated with an exponential distribution, storing possible traffic contents in advance as a table and generating random numbers to select one from the table to determine the traffic contents, or using uniformly generated random numbers to determine the destination and source.

Figure 6 shows an example of the packet capture DB 23 when step S01 is completed. The traffic generation information unit 13 describes the traffic that terminals #1 to #4 shown in Figure 4 send to terminals 5 to #8. Therefore, the packet capture file control unit 22 generates packet capture files Client1.pcapng, Client2.pcapng, Client3.pcapng, and Client4.pcapng that define the traffic to be generated in the packet regenerator 92 as terminals #1 to #4, and stores them in the packet capture DB 23. Each capture file is a Pcap file in which traffic is saved. Figure 7 shows an example of traffic generated by Client1.pcapng to Client4.pcapng.

In step S02-01, the packet capture file control unit 22 generates a packet capture file that is input to the router. In the network topology shown in FIG. 4, if we focus only on router #1, the traffic generated from terminal #1 arrives at router #1 and merges with it after 1 ms, the traffic generated from terminal #2 arrives at router #1 after 3 ms, and the traffic generated from terminal #3 arrives at router #1 after 2 ms. For this reason, the packet capture file control unit 22 generates packet capture files Client1-Router1.pcapng, Client1-Router2.pcapng, and Client1-Router3.pcapng as capture condition files for terminals #1 to #3, with only the time lapse changed. The capture file name "Client1-Router1.pcapng" is the packet time of Client1.pcapng shifted by 1 ms. FIG. 8 shows an example of the packet capture DB when the S02-01 process for router #1 is completed.

In step S02-02, the communication device setting unit 16 registers the FIB and queue information of router #1. In the network topology shown in Figure 4, if we focus only on router #1, we can see that router #1 is a model that forwards all traffic to router #3. For this reason, FIB and queue information such that the destination is router #3, as shown in Figures 9 and 10, is set in the communication device 94. As a result, the communication device 94 and packet capture 93 #1 are connected, similar to routers #1 and #3.

In step S02-03, the packet playback instruction unit 17 instructs the packet playback device 92#1 to play Client1-Router1.pcapping, instructs the packet playback device 92#2 to play Client2-Router1.pcapping, and instructs the packet playback device 92#3 to play Client3-Router1.pcapping. The packet playback device 92#1 plays Client1-Router1.pcapping, the packet playback device 92#2 plays Client1-Router2.pcapping, and the packet playback device 92#3 plays Client1-Router3.pcapping. The packet capture device 93#1 captures the incoming packets and outputs them to Router1. As a result, in step S02-04, Router1.pcapng is stored in the packet capture DB 23, as shown in FIG.

Below, this operation will be performed for all routers, but router #3 after router #2 has been performed will also be illustrated. In the network topology shown in FIG. 4, if we focus only on router #3, the traffic generated from router #1 arrives at router #3 after 2 ms, and the traffic generated from router #2 arrives at router #3 after 1 ms, and merges therewith. For this reason, the packet capture file control unit 22 generates a packet capture file in which only the time lapse has been changed, as a capture condition file. Specifically, Router1-Router3.pcapng is generated by shifting the packet time of Router1.pcapng by 2 ms, and Router2-Router3.pcapng is generated by shifting the packet time of Router2.pcapng by 1 ms. FIG. 12 shows an example of the packet capture DB when the processing of step S02-01 for router #3 is completed.

In step S02-02, the communication device setting unit 16 registers the FIB and queue information of router #3. In the network topology shown in FIG. 4, if we focus only on router #3, router #3 is a model in which it forwards all traffic to router #4. For this reason, FIB and queue information such that the destination is router #4, as shown in FIG. 13 and FIG. 14, is set in the communication device 94. As a result, the communication device 94 and packet capture 93#1 are connected, similar to routers #3 and #4.

In step S02-03, the packet regeneration instruction unit 17 instructs the packet regenerator 92#1 to regenerate Router1-Router3.pcapng, and instructs the packet regenerator 92#2 to regenerate Router2-Router3.pcapng. The packet regenerator 92#1 regenerates Router1-Router3.pcapng, and the packet regenerator 92#2 regenerates Router2-Router3.pcapng. The packet capture 93#1 captures the incoming packets and saves them as Router3.pcapng. As a result, in step S02-04, Router3.pcapng is saved in the packet capture DB 23, as shown in FIG. 15.

An example of the generation of the simulation result of the packet capture analysis unit 24 in step S03 will be described. For example, as shown in FIG. 16, when the packet capture DB 23 has capture files of terminals #1 to #4 and terminals #5 to #8, the capture files of terminals #1 to #4 are compared with the capture files of terminals #5 to #8 to obtain delay times and packet loss rates, and are stored in the simulation result DB 25. The capture files of terminals #5 to #8 are capture result files obtained by generating traffic output from the router #4 with the packet regenerator 92#1, operating the communication device 94 as terminals #5 to #8, capturing the operation results of terminals #5 to #8 with the packet capture 93#1, and acquiring the results as Client5.pcapng, Client6.pcapng, Client7.pcapng, and Client8.pcapng by the packet regeneration result acquisition unit 21.

As described above, in this embodiment, the simulation is divided into a traffic generation flow and a packet processing flow, and in the traffic generation flow, a file is generated in the format of the packet capture 93, and in the packet processing flow, the capture file is sent to the packet regenerator 92, thereby implementing hardware (HW) processing. As a result, in this embodiment, the traffic generated by the packet regenerator 92 is processed by the actual HW, making it possible to offload the simulation of a large number of packets.

Second Embodiment
In this embodiment, step S02 shown in Fig. 3 is different from the first embodiment. In step S02, the following processes shown in Fig. 17 are executed in sequence.
Step S02-11: The packet capture file control unit 22 generates packet capture files, which are input to the router, over the entire simulation time using the network topology information and the packet capture files held in the packet capture DB 23, and stores them in the packet capture DB 23. As a result, a generation condition file for generating traffic in each packet regenerator 92 is stored in the packet capture DB 23.
Step S02-12: The packet capture file control unit 22 generates an expected packet capture file to be output from the router based on the network topology information unit 15 by filtering and summing the packet capture file generated in step S02-11.
Step S02-13: The packet capture analysis unit 24 analyzes the expected packet capture file and measures traffic fluctuations at a pre-set analysis time granularity (e.g., 1 ms) to check for any moments when the speed of the router's output link is exceeded.
Step S02-14: If the traffic fluctuation measurement result does not exceed the speed of the output link, the assumed packet capture file generated in step S02-12 is stored in the packet capture DB 23 as a packet capture obtained by simulation, and the process returns to step S02-11 to process the next router. (The process of step S02-04 in the first embodiment) On the other hand, if the traffic fluctuation measurement result exceeds the speed of the output link, the process proceeds to step S02-15.
Step S 02 - 15 : The communication device setting section 16 registers the information of the selected router in the communication device 94 based on the network topology information section 15 .
Step S02-16: The packet replay instruction unit 17 reproduces the packet capture file generated in step S02-11 from the packet replay device 92. The packet capture device 93 captures traffic sent from the communication device 94.
Step S02-17: The packet replay result acquisition unit 21 stores in the packet capture DB 23 the data stored by the packet capture 93 in step S02-16.

Steps S02-11, S02-15, S02-16, and S02-17 are similar to steps S02-01, S02-02, S02-03, and S02-04 described in the first embodiment. Steps S02-12 to S02-14 will be described below with reference to the network topology shown in FIG.

In the network topology shown in Figure 4, if we focus only on router #1, we can see that the traffic generated from terminal #1 reaches and merges with router #1 after 1 ms, the traffic generated from terminal #2 after 3 ms, and the traffic generated from terminal #3 after 2 ms. Therefore, packet capture files in which only the time lapse has been changed are generated as capture condition files for terminals #1 to #3. As a result, Client1-Router1.pcapng, Client1-Router2.pcapng, and Client1-Router3.pcapng are stored in packet capture DB23, as shown in Figure 8.

The output of router #1 is the sum of terminal #1-router #1, terminal #2-router #1, and terminal #3-router #1. In this embodiment, these are simply summed (for example, using the mergecap command) to obtain the expected packet capture. For example, Client1-Router1.pcapng, Client1-Router2.pcapng, and Client1-Router3.pcapng shown in packet capture DB23 in FIG. 18 are summed using the mergecap command to generate a new expected packet capture file.

The packet capture analysis unit 24 calculates the traffic fluctuations using the expected packet capture file. This allows the traffic fluctuations observed at 1 ms time intervals to be obtained, as shown in FIG. 19.

If you look at it with a one second period, you will not be able to detect instantaneous congestion, so it is better to have a shorter granularity. However, if you cut out a moment, such as 10 us, congestion will occur at that point if packets are generated at the same time, but in reality it will only be about one packet waiting. This measurement time interval is determined in advance based on the time granularity you want to obtain in the simulation and the expected queue length of the router.

In the example shown in Figure 19, since the link speed is not exceeded, the expected packet capture is output as is to router #1 and saved as Router1.pcapng in the packet capture DB 23. This operation will be executed for all routers below, but an example will also be given for router #3 after executing router #2. Note that, like router #1, router #2 does not exceed the link speed, so the expected packet capture = output capture.

Router #3 obtains the combined packet capture from router #1 and router #2 as the assumed packet capture. This allows the packet capture analysis unit 24 to obtain traffic fluctuations seen over a time interval of 1 ms, as shown in Figure 20. In the example shown in Figure 20, the link speed has been exceeded and congestion has occurred, so proceed to step S02-15.

If there is no moment when the speed of the router's output link is exceeded, congestion does not occur and packet simulation is not necessary. In that case, steps S02-15 to S02-17 can be omitted.

As explained above, in this embodiment, for events in the packet processing flow where packet loss is unlikely to occur, the simulation is substituted by the aggregation process of capture files. This allows some of the simulation to be executed in parallel, making it possible to perform traffic simulations at high speed even for high-speed, high-capacity communication networks.

This disclosure can be applied to the information and communications industry.

11: Simulation supervision unit 12: Traffic occurrence simulation unit 13: Traffic occurrence information unit 14: Network topology simulation unit 15: Network topology information unit 16: Communication device setting unit 17: Packet replay instruction unit 21: Packet replay result acquisition unit 22: Packet capture file control unit 23: Packet capture DB
24: Packet capture analysis unit 25: Simulation result DB
91: Computer 92: Packet regenerator 93: Packet capture 94: Communication device

Claims (9)

a packet regenerator for generating traffic based on the packet capture file;
A packet capture that captures packets based on a packet capture file;
A communication device connected to the packet regenerator and the packet capture device;
Connected to
A first process of registering information of routers constituting a network topology in the communication device;
a second process of generating a generation condition file in the form of a packet capture file, the generation condition file defining traffic to be generated in the packet regenerator , based on connection information of the router that has been registered among the routers constituting the network topology ;
a third process of generating a capture condition file in the form of a packet capture file, the capture condition file defining conditions for capturing the packet in the packet capture process, based on connection information of the router that has performed the registration process among the routers constituting the network topology;
A fourth process of generating traffic by causing the packet regenerator to execute the generation condition file; and
A fifth process of capturing packets by causing the packet capture to execute the capture condition file,
for each router in the network topology;
Simulation device. When the router that has performed the registration process among the routers that configure the network topology is connected to a junction, the second process and the third process are executed by adding up packet capture files generated in a transmitting terminal or a router that is connected upstream of the router.
The simulation device according to claim 1 . A traffic generation simulation for simulating the generation, continuation, and termination of a call;
a packet processing simulation for simulating packet transmission and reception processing based on a result of the traffic generation simulation;
Run
executing the packet transmission and reception process of the packet processing simulation using the packet regenerator and the packet capture;
The simulation device according to claim 1 . saving the result of capturing the packets in the packet capture in the form of a packet capture file;
The simulation device according to claim 1 . generating an assumed packet capture file in the form of a packet capture file for generating traffic obtained by adding up traffic transmitted by the plurality of generation condition files using the plurality of generation condition files having a common source or destination in a capture section;
Calculating traffic fluctuations using the assumed packet capture file;
generating traffic by causing the packet regenerator to execute the generation condition file when a packet loss occurs in the calculated traffic fluctuation;
The simulation device according to claim 1 . A simulation device according to any one of claims 1 to 5 ,
the packet regenerator for generating traffic based on a packet capture file;
The packet capture is configured to capture packets based on a packet capture file;
A traffic simulation system comprising: a packet regenerator for generating traffic based on the packet capture file;
A packet capture that captures packets based on a packet capture file;
A communication device connected to the packet regenerator and the packet capture device;
A simulation method executed by a simulation device connected to
The simulation device,
A first process of registering information of routers constituting a network topology in the communication device;
a second process of generating a generation condition file in the form of a packet capture file, the generation condition file defining traffic to be generated in the packet regenerator , based on connection information of the router that has been registered among the routers constituting the network topology ;
a third process of generating a capture condition file in the form of a packet capture file, the capture condition file defining conditions for capturing the packet in the packet capture , based on connection information of the router that has been registered among the routers constituting the network topology;
A fourth process of generating traffic by causing the packet regenerator to execute the generation condition file; and
A fifth process of capturing packets by causing the packet capture to execute the capture condition file,
for each router in the network topology;
Simulation method. When the router that has performed the registration process among the routers that configure the network topology is connected to a junction, the second process and the third process are executed by adding up packet capture files generated in a transmitting terminal or a router that is connected upstream of the router.
The simulation method according to claim 7. A program for causing a computer to realize each of the functional units of the simulation device according to any one of claims 1 to 5 .

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