Frame capture device and frame capture method

Abstract

To provide a frame capture device and a frame capture method that can simplify the device configuration while suppressing the loss of wireless frames.SOLUTION: A frame capture device includes a frequency conversion unit that, when a channel used by a source base station is different from a preset first channel, converts a signal arriving from the source base station into a signal of the same frequency band as the frequency band of the first channel and outputs the signal, and a wireless frame management unit 112 that, when a wireless frame corresponding to the signal output from the frequency conversion unit includes channel information, stores wireless frame information related to the wireless frame in a wireless frame information storage unit 131 in correspondence with MAC address information and channel information included in the wireless frame.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a frame capture device and a frame capture method. [Background Art]

[0002] A capture device that captures communication packets flowing through a network and analyzes traffic on the network by using information included in the communication packets has been proposed (see, for example, Patent Document 1). [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2020-167583 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] By the way, in the case of the capture device described in Patent Document 1, when capturing communication packets flowing through a plurality of channels, for example, a function of capturing communication packets while changing the channel to be used is required. However, with this configuration, since the channel switching function is provided, the device configuration becomes complicated, and there is a risk that communication packets flowing through other channels may be missed while capturing communication packets using any one of the plurality of channels.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a frame capture device and a frame capture method capable of suppressing missing wireless frames while simplifying the device configuration. [Means for Solving the Problem]

[0006] In order to achieve the above object, the frame capture device according to the present invention includes: A frame acquisition unit that acquires wireless frames, A frequency band information storage unit stores frequency band information indicating the frequency band of each of several pre-configured types of channels, associating it with channel information indicating the corresponding channel. If the channel used by the wireless communication device that transmits the wireless frame is different from a preset first channel among the multiple types of channels stored in the frequency band information storage unit, the frequency conversion unit converts the signal arriving from the wireless communication device that transmits the wireless frame into a signal in the same frequency band as the first channel and outputs it. A wireless frame management unit determines whether or not the wireless frame notified by the frame acquisition unit includes the channel information, Based on a notification from the wireless frame management unit, if the wireless frame includes the channel information, the wireless frame information relating to the wireless frame is stored in association with wireless communication device identification information that identifies the wireless communication device that transmits the wireless frame and channel information that indicates the channel used by the wireless communication device that transmits the wireless frame. The “wireless communication device identification information” as used herein is exemplified by the MAC address or BSSID of the wireless communication device.

[0007] From another perspective, the frame capture method according to the present invention is: A frame capture method for capturing wireless frames transmitted by multiple wireless communication devices when there are multiple types of channels used by each of the multiple wireless communication devices, A frequency band information storage step involves storing frequency band information, which indicates the frequency band of each of several types of channels, in association with channel information, which indicates the corresponding channel. If the channel used by the wireless communication device is different from the preset first channel among the multiple types of channels stored in the frequency band information storage step, a frequency conversion step is performed to convert the signal arriving from the wireless communication device into a signal in the same frequency band as the first channel and output it; A determination step to determine whether the wireless frame corresponding to the signal output by the frequency conversion step includes the channel information, If the determination step determines that the wireless frame includes the channel information, the wireless frame information relating to the wireless frame is stored in association with wireless communication device identification information that identifies the wireless communication device that transmits the wireless frame and channel information that indicates the channel used by the wireless communication device that transmits the wireless frame. [Effects of the Invention]

[0008] According to the present invention, if the frequency conversion unit is using a channel other than the first channel, such as the second channel, the frequency conversion unit converts the signal arriving from the source wireless communication device to a signal in the same frequency band as the first channel and outputs it. The wireless frame information storage unit then stores the wireless frame information, associating it with the wireless communication device identification information and channel information contained in the wireless frame, if the wireless frame corresponding to the signal output from the frequency conversion unit includes channel information. As a result, using a single communication interface corresponding to the frequency band of the first channel, both wireless frames flowing through the first channel and wireless frames flowing through the second channel can be acquired, and the wireless frame information relating to the wireless frame can be stored in the wireless frame information storage unit as association with channel information indicating the corresponding first or second channel. Therefore, the frame capture device can be configured with a single communication interface and can capture wireless frames flowing through multiple different channels, such as the first and second channels, without switching the channels used. This simplifies the device configuration while suppressing the loss of wireless frames. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows the configuration of a system including a frame capture device according to an embodiment of the present invention. [Figure 2] This figure shows the hardware configuration of the frame capture device according to the embodiment. [Figure 3] This diagram shows the functional configuration of a frame capture device according to an embodiment. [Figure 4] This figure shows an example of the information stored by the wireless frame information storage unit according to the embodiment. [Figure 5] This is a sequence diagram showing the processing of a system including a frame capture device according to an embodiment. [Figure 6] This is a sequence diagram showing the processing of a system including a frame capture device according to an embodiment. [Figure 7] This flowchart shows an example of the flow of frame capture processing performed by the frame capture device according to the embodiment. [Figure 8] This figure shows another example of the information stored by the wireless frame information storage unit according to the embodiment. [Figure 9] This figure shows the hardware configuration of a frame capture device according to a modified example. [Modes for carrying out the invention]

[0010] Hereinafter, a frame capture device according to an embodiment of the present invention will be described with reference to the drawings. The frame capture device according to this embodiment includes: a wireless frame information storage unit that stores wireless frame information relating to a wireless frame in association with wireless communication device identification information that identifies the wireless communication device that transmits the wireless frame and channel information that indicates the channel used by the wireless communication device that transmits the wireless frame; a frequency conversion unit that, when the channel used by the wireless communication device that transmits the wireless frame is a channel other than a preset first channel, converts the signal arriving from the wireless communication device that transmits the wireless frame to a signal in the same frequency band as the frequency band of the first channel and outputs it; and a wireless frame management unit that, when the wireless frame corresponding to the signal output from the frequency conversion unit includes channel information, stores the wireless frame information in association with the wireless communication device identification information and channel information included in the wireless frame in the wireless frame information storage unit.

[0011] As shown in Figure 1, the frame capture device 1 according to this embodiment is used in a system comprising, for example, two base stations (2A, 2B) and two terminal devices (3A, 3B). The frame capture device 1 captures wireless frames transmitted and received between the base stations 2A, 2B and the terminal devices 3A, 3B.

[0012] As shown in FIG. 2, the frame capture device 1 includes an antenna 12, band-pass filters (hereinafter referred to as "BPF") 13 and 14 configured to pass signals in frequency bands respectively corresponding to two channels, a frequency conversion unit 17, and a control unit 11. The BPF 13 directly outputs, to a communication interface (hereinafter referred to as "communication IF") 104 described later of the control unit 11, a signal in a frequency band corresponding to a preset first channel transmitted from base stations 2A, 2B and terminal devices 3A, 3B and received by the antenna 12. On the other hand, the BPF 14 outputs, to a mixer 16, a signal in a frequency band corresponding to a second channel other than the aforementioned first channel transmitted from the base stations 2A, 2B and terminal devices 3A, 3B and received by the antenna 12. Each of the BPFs 13 and 14 has a function of adjusting the frequency band of a signal to be transmitted based on a control signal input from the control unit 11.

[0013] When the channel used by the source base stations 2A and 2B of the wireless frame received by the frame capture device 1 is the aforementioned second channel, the frequency conversion unit 17 converts a signal transmitted from the base stations 2A and 2B and received by the antenna 12 into a signal in the same frequency band as that of the aforementioned first channel, and outputs the converted signal. The frequency conversion unit 17 includes an oscillator 15 and a mixer 16. The oscillator 15 generates, based on a control signal input from the control unit 11, a signal having a frequency corresponding to the difference frequency between the center frequencies of the respective frequency bands of the first channel and the second channel corresponding to the wireless frame to be captured, and outputs the generated signal to the mixer 16. The mixer 16 mixes the signal in the frequency band of the second channel input from the BPF 14 and the signal input from the oscillator 15, shifts the signal in the frequency band of the second channel to the same frequency band as that of the first channel, and then outputs the shifted signal to the communication IF 104 of the control unit 11.

[0014] The control unit 11 includes a CPU (Central Processing Unit) 101, a main memory unit 102, an auxiliary memory unit 103, a communication interface 104, an oscillator interface (hereinafter referred to as "oscillator IF") 105, a bandpass filter interface (hereinafter referred to as "BPFIF") 106, an input unit 107, and a bus 109 connecting these to each other. The main memory unit 102 is composed of volatile memory and is used as a working area for the CPU 101. The auxiliary memory unit 103 is composed of non-volatile memory. The communication interface 104 has an amplification circuit and a demodulation circuit, and converts analog signals acquired from the BPF 13 and mixer 16 into digital signals and transfers them to the bus 109 based on a communication method that conforms to wireless LAN standards such as IEEE802.11a, b, g, n, etc. Oscillator IF105 receives control information from CPU105 to set the oscillation frequency of oscillator 15, converts the acquired control information into a control signal, and outputs it to oscillator 15. BPFIF106 receives control information from CPU105 to set the frequency bands to be transmitted by BPF13 and 14, respectively, converts the acquired control information into a control signal, and outputs it to BPF13 and 14. Input unit 107 is for the user to input channel information indicating the channel corresponding to the wireless frame to be captured.

[0015] In the control unit 11, the CPU 101 loads a program stored in the auxiliary storage unit 103 into the main storage unit 102 and executes the program, thereby functioning as a frame acquisition unit 111, a wireless frame management unit 112, a channel selection unit 113, a BPF adjustment unit 114, and a conversion control unit 115, as shown in Fig. 3. In addition, as shown in Fig. 3, the auxiliary storage unit 103 shown in Fig. 2 includes a wireless frame information storage unit 131 and a frequency band information storage unit 132. The wireless frame information storage unit 131 stores wireless frame information related to wireless frames including the type of wireless frame, frame length, and the like, based on notifications from the wireless frame management unit 112 (described later), as exemplified in Fig. 4, in association with MAC address information of the transmission source and destination of the wireless frame, and channel information indicating channels used by the transmission source base stations 2A, 2B and terminal devices 3A, 3B. In the example shown in the topmost data row of Fig. 4, for example, it is indicated that the source MAC address of a beacon frame transmitted via channel "1ch" is "00:00:00:11:11:11", and the destination MAC address is set as a broadcast address. The information stored in the wireless frame information storage unit 131 is used, for example, by an application for analyzing a location where a failure occurs on a wireless LAN and checking whether traffic control is performed as designed.

[0016] Returning to Fig. 3, the frequency band information storage unit 132 stores frequency band information indicating the frequency band of each of a plurality of preset types of channels in association with channel information indicating the corresponding channel. For example, the frequency band information corresponding to channel information 1ch in the 2.4 GHz band includes a center frequency of 2412 MHz and a band of 2401 MHz to 2423 MHz. When the frame acquisition unit 111 acquires a frame input from the communication IF 104, it notifies the wireless frame management unit 112 of the acquired frame.

[0017] The wireless frame management unit 112 determines the type of frame to be notified by the frame acquisition unit 111 by referring to a field indicating the frame type of the frame, for example, the "Frame Control" field in the IEEE 802.11 header. Here, the wireless frame management unit 112 determines, for example, that if the frame type is a beacon frame, it is a frame that contains channel information, and if the frame type is a data frame, it is a frame that does not contain channel information. If the frame notified by the frame acquisition unit 111 contains channel information, the wireless frame management unit 112 extracts the channel information and the source and destination MAC address information of the frame contained in the frame, and notifies the wireless frame information storage unit 131 to store the extracted channel information and MAC address information in association with the wireless frame information that contains the frame type information. Here, a frame that contains channel information is a management frame such as a beacon frame. The wireless frame management unit 112 also extracts the source and destination MAC address information stored in, for example, the "Transmitter address" field and the "Receiver Address" field in the IEEE 802.11 header. Furthermore, the wireless frame management unit 112 extracts channel information, for example, the information stored in the "Current Channel" field included in the "DSSS Parameter Set" element of the beacon frame.

[0018] Meanwhile, if the frame notified by the frame acquisition unit 111 does not contain channel information, the wireless frame management unit 112 extracts the source and destination MAC address information of the frame contained in the frame and notifies the wireless frame information storage unit 131 to store the extracted MAC address information in association with the wireless frame information including frame type information. Here, a frame that does not contain channel information is, for example, a data frame. The wireless frame management unit 112 then searches the channel information stored in the wireless frame information storage unit 131 for channel information corresponding to the MAC address information contained in the frame. If channel information is found, the wireless frame management unit 112 notifies the wireless frame information storage unit 131 to store the found channel information in association with the extracted MAC address information. In other words, if the frame corresponding to the signal output from the frequency conversion unit 17 does not contain channel information, the wireless frame management unit 112 identifies the channel information corresponding to the MAC address information contained in the frame from the channel information stored in the wireless frame information storage unit 131, and notifies the wireless frame information storage unit 131 to store the frame information in association with the MAC address information contained in the frame and the identified channel information. On the other hand, if the wireless frame management unit 112 cannot detect channel information, it deletes the corresponding MAC address information and wireless frame information stored in the wireless frame information storage unit 131.

[0019] When the channel selection unit 113 acquires channel information indicating two channels of a wireless frame to be captured, for example, input by the user via the input unit 107, it identifies the frequency band information corresponding to the channel indicated by the acquired channel information from among the frequency band information indicating the frequency bands of multiple pre-set channels stored in the frequency band information storage unit 132. The channel selection unit 113 then notifies the BPF adjustment unit 114 and the conversion control unit 115 of the frequency band information for each of the two identified channels.

[0020] The BPF adjustment unit 114 generates and outputs control information to the BPF 13 to allow signals in the frequency band indicated by one of the two channel frequency band information notified by the channel selection unit 113 to pass through. The BPF adjustment unit 114 also generates and outputs control information to the BPF 14 to allow signals in the frequency band indicated by the other of the two channel frequency band information to pass through. The conversion control unit 115 generates and outputs control information to the oscillator 15 to generate a signal at the difference frequency of the center frequencies of the frequency bands indicated by each of the two channel frequency band information notified by the channel selection unit 113.

[0021] Next, the processing of the system including the frame capture device 1 according to this embodiment will be described with reference to Figures 5 and 6. Here, it is assumed that base station 2B communicates with terminal device 3B using the aforementioned pre-configured first channel, and base station 2A communicates with terminal device 3A using a second channel other than the aforementioned first channel. First, as shown in Figure 5, assume that a management frame containing channel information, generated by base station 2A and set as the source MAC address and the destination broadcast address, is received by terminal device 3A and frame capture device 1 from base station 2A via the second channel (steps S1, S2). In this case, when frame capture device 1 acquires the management frame, the frequency conversion unit 17 converts the frequency so that it is in the same frequency band as the first channel (step S3). Next, frame capture device 1 refers to the field indicating the frame type included in the acquired management frame and determines that it is a frame containing channel information (step S4). Next, the frame capture device 1 extracts channel information and source and destination MAC address information contained in the frame, and stores the extracted channel information and MAC address information in the wireless frame information storage unit 131, associating them with wireless frame information including frame type information (step S5).

[0022] Next, assume that a management frame generated by base station 2B, which includes channel information with the source set to its own MAC address and the destination set to a broadcast address, is received from base station 2B to terminal device 3B and frame capture device 1 via the first channel (steps S6, S7). In this case, frame capture device 1 does not perform the frequency conversion described above. Then, frame capture device 1 refers to a field indicating the frame type included in the acquired management frame and determines that it is a frame that includes channel information (step S8). Subsequently, frame capture device 1 extracts the channel information and the source and destination MAC address information of the frame included in the frame, and stores the extracted channel information and MAC address information in the wireless frame information storage unit 131 in association with the wireless frame information including the frame type information (step S9).

[0023] Next, suppose that a data frame generated by terminal device 3A, with the source being its own MAC address and the destination being the MAC address of base station 2A, is transmitted from terminal device 3A to base station 2A via the second channel (step S10) and also received by frame capture device 1 (step S11). In this case, when frame capture device 1 acquires the data frame, the frequency conversion unit 17 converts the frequency so that it is in the same frequency band as the first channel (step S12). Subsequently, as shown in Figure 6, frame capture device 1 refers to a field indicating the frame type included in the acquired data frame and determines that it is a frame that does not contain channel information (step S13). After that, frame capture device 1 extracts the source and destination MAC address information of the frame included in the frame and stores the extracted MAC address information in the wireless frame information storage unit 131 in association with the wireless frame information including the frame type information (step S14). Next, the frame capture device 1 searches the channel information stored in the wireless frame information storage unit 131 for channel information corresponding to the MAC address information contained in the frame, and assumes that it has detected such channel information (step S15). In this case, the frame capture device 1 stores the detected channel information in the wireless frame information storage unit 131 in association with the extracted MAC address information (step S16).

[0024] Next, a data frame generated by terminal device 3B, with the source being its own MAC address and the destination being the MAC address of base station 2B, is transmitted from terminal device 3B to base station 2B via the first channel (step S17), and is also received by frame capture device 1 (step S18). In this case, frame capture device 1 acquires the data frame without performing the aforementioned frequency conversion, and then, by referring to the field indicating the frame type included in the acquired data frame, determines that it is a frame that does not contain channel information (step S19). Subsequently, frame capture device 1 extracts the source and destination MAC address information of the frame included in the frame, and stores the extracted MAC address information in the wireless frame information storage unit 131 in association with the wireless frame information including the frame type information (step S20). Next, frame capture device 1 searches the channel information stored in the wireless frame information storage unit 131 for channel information corresponding to the MAC address information included in the frame, and determines that the channel information has been detected (step S21). In this case, the frame capture device 1 stores the detected channel information in the wireless frame information storage unit 131, associating it with the extracted MAC address information (step S22).

[0025] Next, the frame capture process performed by the control unit 11 of the frame capture device 1 according to this embodiment will be described with reference to Figure 7. This frame capture process is started when power is supplied to the frame capture device 1. First, the channel selection unit 113 acquires channel information indicating two channels of the wireless frame to be captured, which is input by the user via the input unit 107 (step S101). Then, from the frequency band information indicating the frequency band of each of the multiple preset channels stored in the frequency band information storage unit 132, it identifies the frequency band information corresponding to the channel indicated by the acquired channel information (step S102). Next, the channel selection unit 113 notifies the BPF adjustment unit 114 and the conversion control unit 115 of the frequency band information for each of the two identified channels. Subsequently, the BPF adjustment unit 114 generates and outputs control information to the BPF 13 to allow the signal of the frequency band indicated by the one of the two frequency band information notified by the channel selection unit 113 to pass through. Furthermore, the BPF adjustment unit 114 generates and outputs control information to the BPF 14 to allow the signal of the frequency band indicated by the other frequency band information of the two channels to pass through, based on the other of the two aforementioned frequency band information. In addition, the conversion control unit 115 generates and outputs control information to the oscillator 15 to generate a signal of the difference frequency between the center frequencies of the frequency bands indicated by the frequency band information of the two channels notified by the channel selection unit 113 (step S103). Through the above preparation process, no matter which of the two pre-set wireless signals is received, it passes through the communication IF 104 and a wireless frame is output.

[0026] Next, the frame acquisition unit 111 determines whether the frame capture device 1 has received a wireless signal and whether a frame has been input from the communication IF 104 (step S104). Here, the frame acquisition unit 111 repeatedly executes the process in step S104 unless a frame has been input (step S104: No). On the other hand, if the frame acquisition unit 111 determines that a frame has been input (step S104: Yes), it notifies the wireless frame management unit 112 of the acquired frame.

[0027] Next, the wireless frame management unit 112 refers to a field indicating the frame type of the frame notified by the frame acquisition unit 111 and determines whether the notified frame is a frame containing channel information based on the type of the notified frame (step S105). If the wireless frame management unit 112 determines that the frame contains channel information (step S105: Yes), it extracts the channel information, source and destination MAC address information of the frame contained in the frame, and notifies the wireless frame information storage unit 131 to store the extracted channel information and MAC address information in association with the wireless frame information containing the frame type information (step S106). Subsequently, the process in step S104 is executed again.

[0028] On the other hand, if the wireless frame management unit 112 determines that a frame does not contain channel information (step S105: No), it extracts the source and destination MAC address information of the frame contained in the frame and notifies the wireless frame information storage unit 131 to store the extracted MAC address information in association with the wireless frame information including frame type information (step S107). Next, the wireless frame management unit 112 performs a process to search for channel information corresponding to the MAC address information contained in the frame among the channel information stored in the wireless frame information storage unit 131 (step S108). After that, the wireless frame management unit 112 determines whether or not it was able to detect channel information as a result of performing the process to search for channel information (step S109). Here, if the wireless frame management unit 112 determines that it was able to detect channel information (step S109: Yes), it notifies the wireless frame information storage unit 131 to store the detected channel information in association with the extracted MAC address information (step S110). Then, the process in step S104 is executed again. On the other hand, if the wireless frame management unit 112 determines that it could not detect channel information (step S109: No), it deletes the corresponding MAC address information and wireless frame information stored in the wireless frame information storage unit 131 (step S111). Then, the process in step S104 is executed again.

[0029] Here, the frame capture process of the frame capture device 1 according to this embodiment, as described using Figures 7 and 8, will be explained in detail based on a specific example. Here, it is assumed that the frame capture device 1 receives each wireless frame from base stations 2A, 2B or terminal devices 3A, 3B in the order of, for example, No. 1 to No. 8 in Figure 8. It is also assumed that the first channel is set to "1ch", the second channel to "6ch", the MAC address of base station 2B is set to "00:00:00:11:11:11", the MAC address of base station 2A is set to "00:00:00:22:22:22", the MAC address of terminal device 2B is set to "ff:ff:ff:11:11:11", and the MAC address of terminal device 2A is set to "ff:ff:ff:22:22:22".

[0030] Furthermore, the wireless frames received by the frame capture device 1 shown in Figure 8 from base stations 2A, 2B or terminal devices 3A, 3B may contain various other information besides the information described above. For example, they may include the BSSID, received signal strength, and the data itself (simply the data) that you want to store and transmit in the wireless frame.

[0031] First, suppose frame capture device 1 receives frame No. 1, a beacon frame with a source MAC address of "00:00:00:11:11:11" and a destination MAC address set to a broadcast address, via channel "1ch". In this case, frame capture device 1 refers to the value "0x0008" in the field indicating the frame type and determines that wireless frame No. 1 is a beacon frame. Then, frame capture device 1 associates the received wireless frame No. 1 with the source MAC address "00:00:00:11:11:11", the broadcast address which is the destination MAC address, and the channel information indicating channel "1ch", and stores them in wireless frame information storage unit 131.

[0032] Next, suppose frame capture device 1 receives frame No. 2, a data frame with a source MAC address of "00:00:00:11:11:11" and a destination MAC address of "ff:ff:ff:11:11:11". In this case, frame capture device 1 refers to the value "0x0028" in the field indicating the frame type and determines that wireless frame No. 2 is a data frame. Then, frame capture device 1 searches the channel information stored in wireless frame information storage unit 131 for channel information corresponding to the source MAC address "00:00:00:11:11:11" and destination MAC address "ff:ff:ff:11:11:11". Here, the frame capture device 1 detects channel information indicating channel "1ch" corresponding to the source MAC address "00:00:00:11:11:11", and stores the detected channel information in the wireless frame information storage unit 131, associating it with the MAC address information corresponding to the received wireless frame No. 2.

[0033] Next, suppose frame capture device 1 receives frame No. 3, a data frame with a source MAC address of "ff:ff:ff:22:22:22" and a destination MAC address of "00:00:00:22:22:22". In this case, frame capture device 1 refers to the value "0x0028" in the field indicating the frame type and determines that wireless frame No. 2 is a data frame. Then, frame capture device 1 searches the channel information stored in wireless frame information storage unit 131 for channel information corresponding to the source MAC address "ff:ff:ff:22:22:22" and destination MAC address "00:00:00:22:22:22". At this point, frame capture device 1 cannot find the channel information and deletes the MAC address information and wireless frame information corresponding to the received wireless frame No. 3 from wireless frame information storage unit 131.

[0034] Suppose that the frame capture device 1 then receives a beacon frame, which is frame No. 4, via channel "6ch," with a source MAC address of "00:00:00:22:22:22" and a destination MAC address set to a broadcast address. In this case, the frame capture device 1 refers to the value "0x0008" in the field indicating the type of frame and determines that the wireless frame No. 4 is a beacon frame. The frame capture device 1 then associates the received wireless frame No. 4 with the source MAC address "00:00:00:22:22:22," the broadcast address which is the destination MAC address, and the channel information indicating channel "6ch," and stores them in the wireless frame information storage unit 131.

[0035] Next, suppose the frame capture device 1 receives frame No. 5, a data frame with a source MAC address of "ff:ff:ff:11:11:11" and a destination MAC address of "00:00:00:11:11:11". In this case, the frame capture device 1 refers to the value "0x0028" in the field indicating the frame type and determines that the wireless frame No. 5 is a data frame. Then, the frame capture device 1 searches the channel information stored in the wireless frame information storage unit 131 for channel information corresponding to the source MAC address of "ff:ff:ff:11:11:11" and the destination MAC address of "00:00:00:11:11:11". Here, the frame capture device 1 detects channel information indicating channel "1ch" corresponding to the destination MAC address "00:00:00:11:11:11", and stores the detected channel information in the wireless frame information storage unit 131, associating it with the MAC address information of the received wireless frame No. 5.

[0036] Next, suppose frame capture device 1 receives frame No. 6, a data frame with a source MAC address of "00:00:00:11:11:11" and a destination MAC address of "ff:ff:ff:11:11:11". In this case, frame capture device 1 refers to the value "0x0028" in the field indicating the frame type and determines that wireless frame No. 6 is a data frame. Then, frame capture device 1 searches the channel information stored in wireless frame information storage unit 131 for channel information corresponding to the source MAC address "00:00:00:11:11:11" and destination MAC address "ff:ff:ff:11:11:11". Here, the frame capture device 1 detects channel information indicating channel "1ch" corresponding to the source MAC address "00:00:00:11:11:11", and stores the detected channel information in the wireless frame information storage unit 131, associating it with the MAC address information corresponding to the received wireless frame No. 6.

[0037] Suppose that frame capture device 1 then receives frame No. 7, a data frame with a source MAC address of "ff:ff:ff:ff:22:22:22" and a destination MAC address of "00:00:00:22:22:22". In this case, frame capture device 1 refers to the value "0x0028" in the field indicating the frame type and determines that wireless frame No. 7 is a data frame. Then, frame capture device 1 searches the channel information stored in wireless frame information storage unit 131 for channel information corresponding to a source MAC address of "ff:ff:ff:ff:22:22:22" and a destination MAC address of "00:00:00:22:22:22". Here, the frame capture device 1 detects channel information indicating channel "6ch" corresponding to the destination MAC address "00:00:00:22:22:22", and stores the detected channel information in the wireless frame information storage unit 131, associating it with the MAC address information corresponding to the received wireless frame No. 7.

[0038] Next, suppose frame capture device 1 receives frame No. 8, a data frame with a source MAC address of "00:00:00:22:22:22" and a destination MAC address of "ff:ff:ff:ff:22:22:22". In this case, frame capture device 1 refers to the value "0x0028" in the field indicating the frame type and determines that wireless frame No. 7 is a data frame. Then, frame capture device 1 searches the channel information stored in wireless frame information storage unit 131 for channel information corresponding to a source MAC address of "00:00:00:22:22:22" and a destination MAC address of "ff:ff:ff:ff:22:22:22". Here, the frame capture device 1 detects channel information indicating channel "6ch" corresponding to the source MAC address "00:00:00:22:22:22", and stores the detected channel information in the wireless frame information storage unit 131, associating it with the MAC address information corresponding to the received wireless frame No. 7. As a result, the wireless frame information storage unit 131 stores the information shown in Figure 4.

[0039] As described above, in the frame capture device 1 according to this embodiment, if the channel used by the source base stations 2A and 2B of the wireless frame is a second channel other than the first channel, the frequency conversion unit 17 converts the signal arriving from the source base stations 2A and 2B into a signal in the same frequency band as the first channel and outputs it. The wireless frame management unit 112 then stores the frame information in the wireless frame information storage unit 131, associating it with the MAC address information and channel information of the base stations 2A and 2B included in the wireless frame, if the frame corresponding to the signal output from the frequency conversion unit 17 contains channel information. As a result, using a single communication IF 104 corresponding to the frequency band of the first channel, both wireless frames flowing on the first channel and wireless frames flowing on the second channel can be acquired, and the wireless frame information related to the wireless frame can be stored in the wireless frame information storage unit 131, associating it with channel information indicating the corresponding first channel or second channel. Therefore, by configuring the frame capture device 1 to have a single communication IF 104, it is possible to capture wireless frames flowing through the first and second channels without switching the channels used. This simplifies the device configuration while suppressing the loss of wireless frames.

[0040] In other words, the frame capture device 1 according to this embodiment suppresses the number of communication IF104s installed and eliminates the need for channel switching operations of the wireless frames to be captured. This suppresses the loss of wireless frames that arrive during the overhead time that occurs during switching operations, thereby enabling seamless capture.

[0041] Although embodiments of the present invention have been described above, the present invention is not limited to the configurations of these embodiments. The present invention includes embodiments and variations that are appropriately combined, as well as those that are appropriately modified therefrom.

[0042] Furthermore, for example, if the frame capture device receives a wireless frame containing channel information from base stations 2A and 2B, it may extract BSSID information indicating the BSSID (Basic Service Set Identifier) ​​and channel information contained in the wireless frame, and store the extracted channel information and BSSID information in the wireless frame information storage unit 131 in association with the wireless frame information including frame type information. Also, if the wireless frame does not contain channel information, the frame capture device may extract the source and BSSID information of the frame contained in the wireless frame, and store the extracted BSSID information in the wireless frame information storage unit 131 in association with the aforementioned wireless frame information.Then, the frame capture device 1 may search the channel information stored in the wireless frame information storage unit 131 for channel information corresponding to the BSSID information contained in the frame, and if channel information is found, store the detected channel information in the wireless frame information storage unit 131 in association with the extracted BSSID information.

[0043] Furthermore, although the above embodiment described a system comprising two base stations and two terminal devices, the present invention is not limited to the number of base stations and terminal devices, or in other words, the number of channels used, which is two channels, the first channel and the second channel.

[0044] Furthermore, in the embodiment, for example, the frame capture device 2001 shown in Figure 9 may include a BPF2014 that integrates the functions of the BPF14 and BPF13 shown in Figure 2. In other words, the BPF2014 may have passbands for both BPF13 and BPF14. This configuration reduces the signal path and lowers design costs.

[0045] Furthermore, the various functions of the control unit 11 of the frame capture device 1 shown in Figure 2 according to the present invention can be realized using a computer system, not a dedicated system. For example, the control unit 11 may be configured by distributing a program for performing the above operations to a computer connected to a network, stored on a non-temporary recording medium (such as a CD-ROM) that can be read by the computer system, and then installing the program into the computer system. The method of providing the program to the computer is also arbitrary. For example, the program may be uploaded to a server on a communication line and distributed to the computer via the communication line. [Industrial applicability]

[0046] The present invention is suitable as a frame capture device that can capture wireless frames flowing over a wireless LAN, thereby enabling analysis of fault locations on the wireless LAN and verification of whether traffic control (QoS, etc.) is being executed as designed. [Explanation of Symbols]

[0047] 1, 2001: Frame capture device, 2A, 2B: Base station, 3A, 3B: Terminal device, 11: Control unit, 12: Antenna, 13, 14, 2014: BPF, 15: Oscillator, 16: Mixer, 17: Frequency conversion unit, 101: CPU, 102: Main memory unit, 103: Auxiliary memory unit, 104: Communication IF, 105: Oscillator IF, 106: BPF IF, 107: Input unit, 109: Bus, 111: Wireless frame acquisition unit, 112: Wireless frame management unit, 113: Channel selection unit, 114: BPF adjustment unit, 115: Conversion control unit, 131: Wireless frame information storage unit, 132: Frequency band information storage unit

Claims

1. A frame acquisition unit that acquires wireless frames, A frequency band information storage unit stores frequency band information indicating the frequency band of each of several pre-configured types of channels, associating it with channel information indicating the corresponding channel. If the channel used by the wireless communication device that transmits the wireless frame is different from a preset first channel among the multiple types of channels stored in the frequency band information storage unit, the frequency conversion unit converts the signal arriving from the wireless communication device that transmits the signal to a signal in the same frequency band as the first channel and outputs it. A wireless frame management unit determines whether or not the wireless frame notified by the frame acquisition unit includes the channel information, Based on a notification from the wireless frame management unit, if the wireless frame includes the channel information, the wireless frame information relating to the wireless frame is stored in association with wireless communication device identification information that identifies the wireless communication device that transmits the wireless frame, and channel information that indicates the channel used by the wireless communication device that transmits the wireless frame. Frame capture device.

2. Based on the notification from the wireless frame management unit, if the wireless frame information is not included, the wireless frame information storage unit identifies the channel information corresponding to the wireless communication device identification information included in the wireless frame from among the channel information stored in the wireless frame information storage unit, and stores the wireless frame information in association with the wireless communication device identification information included in the wireless frame and the identified channel information. The frame capture device according to claim 1.

3. The wireless frame corresponding to the signal output from the frequency conversion unit is a beacon frame. The frame capture device according to claim 1.

4. The wireless communication device identification information indicates the MAC address unique to the transmitting wireless communication device. A frame capture device according to claim 1 or 2.

5. A frame capture method for capturing wireless frames transmitted by multiple wireless communication devices when there are multiple types of channels used by each of the multiple wireless communication devices, A frequency band information storage step involves storing frequency band information, which indicates the frequency band of each of several types of channels, in association with channel information, which indicates the corresponding channel. If the channel used by the wireless communication device is different from the preset first channel among the multiple types of channels stored in the frequency band information storage step, a frequency conversion step is performed to convert the signal arriving from the wireless communication device into a signal in the same frequency band as the first channel and output it. A determination step to determine whether the wireless frame corresponding to the signal output by the frequency conversion step includes the channel information, If the determination step determines that the wireless frame includes the channel information, the wireless frame information relating to the wireless frame is stored in association with wireless communication device identification information that identifies the wireless communication device that transmits the wireless frame, and channel information that indicates the channel used by the wireless communication device that transmits the wireless frame. Frame capture method.

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