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 technology]

[0002] 2. Description of the Related Art There has been proposed a capture device that captures communication packets flowing through a network and analyzes traffic on the network using information contained in the communication packets (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-167583 A Summary of the Invention [Problem to be solved by the invention]

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

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a frame capture device and a frame capture method that can reduce the loss of wireless frames while simplifying the device configuration. [Means for solving the problem]

[0006] In order to achieve the above object, a frame capture device according to the present invention comprises: a frame acquisition unit that acquires a wireless frame; a frequency band information storage unit that stores frequency band information indicating a frequency band of each of a plurality of types of channels that have been set in advance in association with channel information indicating the corresponding channel; a frequency conversion unit that converts a signal arriving from the wireless communication device that is a source of the wireless frame into a signal having the same frequency band as the frequency band of the first channel when the channel used by the wireless communication device that is a source of the wireless frame is a channel different from a first channel that is preset among the multiple types of channels stored in the frequency band information storage unit, and outputs the signal; a wireless frame management unit that determines whether the wireless frame notified from the frame acquisition unit includes the channel information; The wireless communication device includes a wireless frame information storage unit that, when the wireless frame includes the channel information based on a notification from the wireless frame management unit, stores the wireless frame information regarding the wireless frame in correspondence with wireless communication device identification information that identifies the wireless communication device that transmitted the wireless frame and channel information that indicates the channel used by the wireless communication device that transmitted the wireless frame. The "wireless communication device identification information" referred to here is exemplified by the MAC address or BSSID of the wireless communication device.

[0007] A frame capture method according to another aspect of the present invention comprises: 1. A frame capture method for capturing wireless frames transmitted by a plurality of wireless communication devices when a plurality of types of channels are used by the wireless communication devices, comprising the steps of: a frequency band information storage step of storing frequency band information indicating a frequency band of each of a plurality of types of channels in association with channel information indicating the corresponding channel; a frequency conversion step of converting a signal arriving from the wireless communication device into a signal having the same frequency band as the frequency band of the first channel and outputting the signal, when the channel used by the wireless communication device is a channel different from a first channel that is preset among the plurality of types of channels stored in the frequency band information storage step; a determination step of determining whether the radio frame corresponding to the signal output by the frequency conversion step includes the channel information; The method includes a radio frame information storage step of, when it is determined by the determination step that the radio frame includes the channel information, storing the radio frame information regarding the radio frame in correspondence with radio communication device identification information that identifies the radio communication device that transmitted the radio frame and channel information that indicates the channel used by the radio communication device that transmitted the radio frame. Effect of the Invention

[0008] According to the present invention, when the channel used by the wireless communication device that is the source of the wireless frame is a channel other than the first channel, for example, the second channel, the frequency conversion unit converts the signal arriving from the wireless communication device that is the source of the wireless frame into a signal of the same frequency band as the frequency band of the first channel and outputs the converted signal. Then, when the wireless frame corresponding to the signal output from the frequency conversion unit includes channel information, the wireless frame information storage unit stores the wireless frame information in association with the wireless communication device identification information and the channel information included in the wireless frame. This allows both the wireless frame flowing through the first channel and the wireless frame flowing through the second channel to be acquired using one communication interface corresponding to the frequency band of the first channel, and the wireless frame information related to the wireless frame to be stored in the wireless frame information storage unit in association with the channel information indicating the corresponding first channel or second channel. Therefore, while the frame capture device is configured to have one communication interface, it is possible to capture wireless frames flowing through multiple different channels, such as the first channel and the second channel, without switching the channel to be used, and thus it is possible to simplify the device configuration and suppress loss of wireless frames. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing a configuration of a system including a frame capture device according to an embodiment of the present invention. [Diagram 2] 1 is a diagram illustrating a hardware configuration of a frame capture device according to an embodiment. [Diagram 3] 1 is a diagram illustrating a functional configuration of a frame capture device according to an embodiment. [Figure 4] 5 is a diagram illustrating an example of information stored in a radio frame information storage unit according to the embodiment. FIG. [Diagram 5] FIG. 4 is a sequence diagram showing the processing of a system including a frame capture device according to an embodiment. [Figure 6] FIG. 4 is a sequence diagram showing the processing of a system including a frame capture device according to an embodiment. [Figure 7] 10 is a flowchart showing an example of the flow of a frame capture process executed by the frame capture device according to the embodiment. [Figure 8] 11 is a diagram illustrating another example of information stored in the radio frame information storage unit according to the embodiment. FIG. [Figure 9] FIG. 13 is a diagram illustrating a hardware configuration of a frame capture device according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A frame capture device according to an embodiment of the present invention will be described below with reference to the drawings. The frame capture device according to the embodiment includes a wireless frame information storage unit that stores wireless frame information related to a wireless frame in association with wireless communication device identification information that identifies a wireless communication device that is a source of the wireless frame and channel information that indicates a channel used by the wireless communication device of the source, a frequency conversion unit that converts a signal arriving from the wireless communication device of the source into a signal of the same frequency band as the frequency band of the first channel and outputs the converted signal when the channel used by the wireless communication device of the source is a channel different from a first channel set in advance, and a wireless frame management unit that stores the wireless frame information in the wireless frame information storage unit in association with the wireless communication device identification information and the channel information included in the wireless frame when the wireless frame corresponding to the signal output from the frequency conversion unit includes channel information.

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

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

[0013] When the channel used by the base station 2A, 2B that is the transmission source of the wireless frame received by the frame capture device 1 is the above-mentioned second channel, the frequency conversion unit 17 converts the signal transmitted from the base station 2A, 2B and received by the antenna 12 into a signal of the same frequency band as the above-mentioned frequency band of the first channel and outputs the converted signal. The frequency conversion unit 17 has an oscillator 15 and a mixer 16. The oscillator 15 generates a signal of a frequency equivalent to a difference frequency between the center frequencies of the frequency bands of the first channel and the second channel corresponding to the wireless frame to be captured based on a control signal input from the control unit 11, and outputs the generated signal to the mixer 16. The mixer 16 mixes the signal of the frequency band of the second channel input from the BPF 14 with the signal input from the oscillator 15, thereby shifting the signal of the frequency band of the second channel to the same frequency band as the first channel, and outputs the resulting 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 102, an auxiliary memory 103, a communication IF 104, an oscillator interface (hereinafter referred to as "oscillator IF") 105, a band pass filter interface (hereinafter referred to as "BPFIF") 106, an input unit 107, and a bus 109 connecting these to each other. The main memory 102 is made of a volatile memory and is used as a working area for the CPU 101. The auxiliary memory 103 is made of a non-volatile memory. The communication interface 104 includes an amplifier circuit and a demodulator 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 conforming to a wireless LAN standard such as IEEE802.11a, b, g, n. When oscillator IF 105 acquires control information for setting the oscillation frequency of oscillator 15 transferred from CPU 105, it converts the acquired control information into a control signal and outputs it to oscillator 15. When BPFIF 106 acquires control information for setting the frequency bands to be transmitted by BPFs 13 and 14 transferred from CPU 105, it converts the acquired control information into a control signal and outputs it to BPFs 13 and 14. Input unit 107 allows a user to input channel information indicating a channel corresponding to a 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 it, 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. The auxiliary storage unit 103 shown in Fig. 2 also has a wireless frame information storage unit 131 and a frequency band information storage unit 132, as shown in Fig. 3. Based on a notification from the wireless frame management unit 112 (described later), the wireless frame information storage unit 131 stores wireless frame information related to the wireless frame, including the type of wireless frame, the frame length, etc., in association with MAC address information of the source and destination of the wireless frame, and channel information indicating the channels used by the source base stations 2A and 2B and the terminal devices 3A and 3B, as shown in Fig. 4, for example. 4, for example, the source MAC address of the beacon frame transmitted through the channel "1ch" is set to "00:00:00:11:11:11", and the destination MAC address is set to the broadcast address. The information stored in the wireless frame information storage unit 131 is used by applications for analyzing the location of a fault on the wireless LAN and for checking whether traffic control is being 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 types of preset channels in association with channel information indicating the corresponding channel. For example, the frequency band information corresponding to channel information 1ch at 2.4 GHz is center frequency: 2412 kHz, band: 2402 kHz to 2422 kHz, etc. 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 judges the type of the frame notified by the frame acquisition unit 111, referring to a field indicating the frame type of the frame, for example, the "Frame Control" field of the IEEE802.11 header. Here, for example, if the frame type is a beacon frame, the wireless frame management unit 112 judges that the frame includes channel information, and if the frame type is a data frame, the wireless frame management unit 112 judges that the frame does not include channel information. If the frame notified by the frame acquisition unit 111 includes channel information, the wireless frame management unit 112 extracts the channel information included in the frame and the MAC address information of the source and destination of the frame, and notifies that the extracted channel information and MAC address information are stored in the wireless frame information storage unit 131 in association with the wireless frame information including the frame type information. Here, the frame including the channel information is, for example, a management frame such as a beacon frame. In addition, the wireless frame management unit 112 extracts information stored in, for example, the "Transmitter address" field and the "Receiver Address" field of the IEEE802.11 header as the MAC address information of the source and destination. Furthermore, the wireless frame management unit 112 extracts, as channel information, information stored in the "Current Channel" field included in the "DSSS Parameter Set" element of the beacon frame, for example.

[0018] On the other hand, when the frame notified from the frame acquisition unit 111 does not include channel information, the wireless frame management unit 112 extracts MAC address information of the source and destination of the frame included 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 the frame type information. Here, the frame not including channel information is, for example, a data frame. Then, the wireless frame management unit 112 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. Then, when the wireless frame management unit 112 detects the channel information, it notifies the wireless frame information storage unit 131 to store the detected channel information in association with the extracted MAC address information. In other words, when a frame corresponding to a signal output from the frequency conversion unit 17 does not contain channel information, the wireless frame management unit 112 identifies 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 issues a notification to the effect that the frame information is to be stored in the wireless frame information storage unit 131 in association with the MAC address information contained in the frame and the identified channel information. On the other hand, when the wireless frame management unit 112 cannot detect the 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 radio frame to be captured, input by a user via the input unit 107, for example, the channel selection unit 113 identifies frequency band information corresponding to the channel indicated by the acquired channel information from frequency band information indicating the frequency bands of each of a plurality of preset channels stored in the frequency band information storage unit 132. Then, the channel selection unit 113 notifies the BPF adjustment unit 114 and the conversion control unit 115 of the frequency band information of each of the identified two channels.

[0020] Based on one of the frequency band information of the two channels notified by the channel selection unit 113, the BPF adjustment unit 114 generates and outputs control information for passing through the BPF 13 a signal of a frequency band indicated by the one of the frequency band information. Based on the other of the frequency band information of the two channels, the BPF adjustment unit 114 generates and outputs control information for passing through the BPF 14 a signal of a frequency band indicated by the other of the frequency band information. The conversion control unit 115 generates and outputs control information for causing the oscillator 15 to generate a signal of a 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.

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

[0022] Next, assume that a management frame including channel information, which is generated by the base station 2B and has its own MAC address set as the source and the broadcast address set as the destination, is received from the base station 2B via the first channel by the terminal device 3B and the frame capture device 1 (steps S6 and S7). In this case, the frame capture device 1 does not perform the above-mentioned frequency conversion. Then, the frame capture device 1 refers to a field indicating the frame type included in the acquired management frame and determines that the frame is one including channel information (step S8). After that, the frame capture device 1 extracts the channel information and the MAC address information of the source and destination 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, a data frame generated by the terminal device 3A, with its source set to its own MAC address and its destination set to the MAC address of the base station 2A, is transmitted from the terminal device 3A to the base station 2A via the second channel (step S10), and is also received by the frame capture device 1 (step S11). In this case, when the frame capture device 1 acquires the data frame, the frequency conversion unit 17 converts the frequency so that the frequency band is the same as the frequency band of the first channel (step S12). Next, as shown in FIG. 6, the frame capture device 1 refers to a field indicating the frame type included in the acquired data frame and determines that the frame does not include channel information (step S13). After that, the frame capture device 1 extracts the MAC address information of the source and destination 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 for channel information corresponding to the MAC address information included in the frame among the channel information stored in the wireless frame information storage unit 131, and detects the 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 the terminal device 3B, with its source set to its own MAC address and its destination set to the MAC address of the base station 2B, is transmitted from the terminal device 3B to the base station 2B via the first channel (step S17), and is also received by the frame capture device 1 (step S18). In this case, the frame capture device 1 does not convert the frequency as described above, and when it acquires the data frame, it refers to a field indicating the frame type contained in the acquired data frame and determines that the frame does not contain channel information (step S19). After that, the frame capture device 1 extracts the MAC address information of the source and destination of the frame contained 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 containing the frame type information (step S20). Next, the frame capture device 1 searches 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, and detects the channel information (step S21). 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 S22).

[0025] Next, the frame capture process executed by the control unit 11 of the frame capture device 1 according to the present embodiment will be described with reference to FIG. 7. This frame capture process is started when the power supply to the frame capture device 1 is turned on. First, when the channel selection unit 113 acquires channel information indicating two channels of a radio frame to be captured, input by the user via the input unit 107 (step S101), the channel selection unit 113 identifies frequency band information corresponding to the channel indicated by the acquired channel information from frequency band information indicating the frequency bands of each of a plurality of pre-set channels stored in the frequency band information storage unit 132 (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 of each of the identified two channels. Next, the BPF adjustment unit 114 generates and outputs control information for passing a signal of a frequency band indicated by one of the frequency band information of the two channels notified by the channel selection unit 113 through the BPF 13. Furthermore, the BPF adjustment unit 114 generates and outputs control information for passing a signal of a frequency band indicated by the other frequency band information of the two channels through the BPF 14, based on the other of the frequency band information of the two channels described above. The conversion control unit 115 also generates and outputs control information for causing the oscillator 15 to generate a signal of a 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, whichever wireless signal is received on either of the two preset channels, it passes through the communication IF 104, and a wireless frame is output.

[0026] Next, the frame acquisition unit 111 determines whether or not the frame capture device 1 receives a wireless signal and a frame has been input from the communication IF 104 (step S104). Here, the frame acquisition unit 111 repeatedly executes the process of step S104 unless a frame has been input (step S104: No). On the other hand, when 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 the field indicating the frame type of the frame notified from the frame acquisition unit 111, and determines whether the notified frame is a frame including channel information based on the notified frame type (step S105). If the wireless frame management unit 112 determines that the frame includes channel information (step S105: Yes), it extracts the channel information and the MAC address information of the frame's sender and destination included 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 including the frame type information (step S106). Then, the process of step S104 is executed again.

[0028] On the other hand, when the wireless frame management unit 112 determines that the frame does not include channel information (step S105: No), it extracts MAC address information of the frame's source and destination included in the frame, and notifies the wireless frame information storage unit 131 that the extracted MAC address information is to be stored in association with the wireless frame information including the frame type information (step S107). Next, the wireless frame management unit 112 executes a process of searching for channel information corresponding to the MAC address information included in the frame from the channel information stored in the wireless frame information storage unit 131 (step S108). After that, the wireless frame management unit 112 determines whether the channel information has been detected as a result of executing the process of searching for the channel information (step S109). Here, when the wireless frame management unit 112 determines that the channel information has been detected (step S109: Yes), it notifies the wireless frame information storage unit 131 that the detected channel information is to be stored in association with the extracted MAC address information (step S110). Then, the process of step S104 is executed again. On the other hand, if the wireless frame management unit 112 determines that the channel information cannot be detected (step S109: No), the wireless frame management unit 112 deletes the corresponding MAC address information and wireless frame information stored in the wireless frame information storage unit 131 (step S111). Then, the process of step S104 is executed again.

[0029] Here, the frame capture process of the frame capture device 1 according to the present embodiment described with reference to Figures 7 and 8 will be described in detail based on a specific example. Here, it is assumed that the frame capture device 1 receives wireless frames from the base stations 2A, 2B or the 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 is set to "6ch", the MAC address of the base station 2B is set to "00:00:00:11:11:11", the MAC address of the base station 2A is set to "00:00:00:22:22:22", the MAC address of the terminal device 2B is set to "ff:ff:ff:11:11:11", and the MAC address of the terminal device 2A is set to "ff:ff:ff:22:22:22".

[0030] 8 may include various information other than the above information in the wireless frame received from the base stations 2A and 2B or the terminal devices 3A and 3B. For example, the information may include the BSSID, the received signal strength, and the data itself (simply data) to be stored in the wireless frame and transmitted / received.

[0031] First, assume that the frame capture device 1 receives a beacon frame, which is frame No. 1, 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, the frame capture device 1 references the value "0x0008" of the field indicating the frame type and determines that the wireless frame No. 1 is a beacon frame. Then, the frame capture device 1 stores in the wireless frame information storage unit 131 the source MAC address "00:00:00:11:11:11" and the destination MAC address, which is a broadcast address, corresponding to the received wireless frame No. 1, in association with the channel information indicating the channel "1ch."

[0032] Next, assume that the frame capture device 1 receives a data frame, which is frame No. 2, with a source MAC address set to "00:00:00:11:11:11" and a destination MAC address set to "ff:ff:ff:11:11:11". In this case, the frame capture device 1 references the value "0x0028" of the field indicating the frame type and determines that the wireless frame No. 2 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 "00:00:00:11:11:11" and the destination MAC address "ff:ff:ff:11:11:11". Here, the frame capture device 1 detects channel information indicating the 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 in association with the MAC address information corresponding to the received wireless frame No. 2.

[0033] Next, assume that the frame capture device 1 receives a data frame, which is frame No. 3, with a source MAC address set to "ff:ff:ff:22:22:22" and a destination MAC address set to "00:00:00:22:22:22". In this case, the frame capture device 1 references the value "0x0028" of the field indicating the frame type and determines that the wireless frame No. 2 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 "ff:ff:ff:22:22:22" and the destination MAC address "00:00:00:22:22:22". Here, the frame capture device 1 is unable to detect the channel information and deletes the MAC address information and wireless frame information corresponding to the received wireless frame No. 3 from the wireless frame information storage unit 131.

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

[0035] Next, assume that the frame capture device 1 receives a data frame, which is frame No. 5, with a source MAC address set to "ff:ff:ff:11:11:11" and a destination MAC address set to "00:00:00:11:11:11". In this case, the frame capture device 1 references the value "0x0028" of 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 "ff:ff:ff:11:11:11" and the destination MAC address "00:00:00:11:11:11". Here, the frame capture device 1 detects channel information indicating the 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 memory unit 131 in correspondence with the MAC address information of the received wireless frame No. 5.

[0036] Next, assume that the frame capture device 1 receives a data frame, which is frame No. 6, with a source MAC address set to "00:00:00:11:11:11" and a destination MAC address set to "ff:ff:ff:11:11:11". In this case, the frame capture device 1 references the value "0x0028" of the field indicating the frame type and determines that the wireless frame No. 6 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 "00:00:00:11:11:11" and the destination MAC address "ff:ff:ff:11:11:11". Here, the frame capture device 1 detects channel information indicating the 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 in association with the MAC address information corresponding to the received wireless frame No. 6.

[0037] Thereafter, it is assumed that the frame capture device 1 receives a data frame, which is frame No. 7, with a source MAC address set to "ff:ff:ff:ff:22:22:22" and a destination MAC address set to "00:00:00:22:22:22". In this case, the frame capture device 1 references the value "0x0028" of the field indicating the frame type and determines that the wireless frame No. 7 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 "ff:ff:ff:ff:22:22:22" and the destination MAC address "00:00:00:22:22:22". Here, the frame capture device 1 detects channel information indicating the 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 in association with the MAC address information corresponding to the received wireless frame No. 7.

[0038] Next, it is assumed that the frame capture device 1 receives a data frame, which is frame No. 8, with a source MAC address set to "00:00:00:22:22:22" and a destination MAC address set to "ff:ff:ff:ff:22:22:22". In this case, the frame capture device 1 references the value "0x0028" of the field indicating the frame type and determines that the wireless frame No. 7 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 "00:00:00:22:22:22" and the destination MAC address "ff:ff:ff:ff:22:22:22". Here, the frame capture device 1 detects channel information indicating the 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 in association with the MAC address information corresponding to the received wireless frame No. 7. As a result, the wireless frame information storage unit 131 stores information as shown in FIG.

[0039] As described above, in the frame capture device 1 according to the present embodiment, when the channel used by the base stations 2A and 2B that are the transmission source of the wireless frame is the second channel other than the first channel, the frequency conversion unit 17 converts the signal arriving from the transmission source base station 2A or 2B into a signal of the same frequency band as the frequency band of the first channel and outputs the converted signal. Then, when the frame corresponding to the signal output from the frequency conversion unit 17 includes channel information, the wireless frame management unit 112 stores the frame information in the wireless frame information storage unit 131 in association with the MAC address information and channel information of the base stations 2A and 2B included in the wireless frame. In this way, both the wireless frame flowing through the first channel and the wireless frame flowing through the second channel can be acquired using one communication IF 104 corresponding to the frequency band of the first channel, and the wireless frame information related to the wireless frame can be stored in the wireless frame information storage unit 131 in association with the channel information indicating the corresponding first channel or second channel. Therefore, while the frame capture device 1 is configured with one communication IF 104, it is possible to capture wireless frames flowing through the first and second channels without switching the channel to be used, thereby simplifying the device configuration and reducing the risk of missing wireless frames.

[0040] In other words, according to the frame capture device 1 of this embodiment, the number of communication IFs 104 installed can be reduced while eliminating the need to switch channels for the wireless frames to be captured, thereby reducing the loss of wireless frames that arrive within the overhead time that occurs during the switching operation, thereby achieving seamless capture.

[0041] Although the embodiment of the present invention has been described above, the present invention is not limited to the configuration of the embodiment. The present invention includes appropriate combinations of the embodiment and the modified examples, and appropriate modifications thereto.

[0042] Also, for example, when the frame capture device receives a wireless frame including channel information from the base stations 2A and 2B, it may extract BSSID information indicating a Basic Service Set Identifier (BSSID) and channel information included 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, when the wireless frame does not include channel information, the frame capture device extracts the frame sender and BSSID information included in the wireless frame, and stores the extracted BSSID information in association with the wireless frame information in the wireless frame information storage unit 131. Then, the frame capture device 1 may search for channel information corresponding to the BSSID information included in the frame from the channel information stored in the wireless frame information storage unit 131, and when the channel information is detected, store the detected channel information in the wireless frame information storage unit 131 in association with the extracted BSSID information.

[0043] In addition, in the above embodiment, a system having two base stations and two terminal devices has been described, but the present invention is not limited to the number of base stations and terminal devices, in other words, the number of channels used, which are two, the first channel and the second channel.

[0044] In the embodiment, for example, a frame capture device 2001 shown in Fig. 9 may include a BPF 2014 that integrates the functions of the BPF 14 and the BPF 13 shown in Fig. 2. In other words, the BPF 2014 may include the pass frequency bands of both the BPF 13 and the BPF 14. With this configuration, the signal path can be reduced, and the design cost can be reduced.

[0045] The various functions of the control unit 11 of the frame capture device 1 shown in Fig. 2 according to the present invention can be realized by using a computer system, not a dedicated system. For example, the above-mentioned control unit 11 may be configured by distributing a program for executing the above operations to a computer connected to a network by storing the program in a non-transitory recording medium (such as a CD-ROM) that can be read by the computer system, and installing the program in the computer system. In addition, any method may be used to provide the program to the computer. 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 analyze the location of faults on a wireless LAN and confirm whether traffic control (QoS, etc.) is being executed as designed by capturing wireless frames flowing over a wireless LAN. [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 a wireless frame; a frequency band information storage unit that stores frequency band information indicating a frequency band of each of a plurality of types of channels that have been set in advance in association with channel information indicating the corresponding channel; a frequency conversion unit that converts a signal arriving from the wireless communication device that is a source of the wireless frame into a signal having the same frequency band as the frequency band of the first channel when the channel used by the wireless communication device that is a source of the wireless frame is a channel different from a first channel that is preset among the plurality of types of channels stored in the frequency band information storage unit, and outputs the signal; a wireless frame management unit that determines whether the wireless frame notified from the frame acquisition unit includes the channel information; a wireless frame information storage unit configured to store, when the wireless frame includes the channel information based on a notification from the wireless frame management unit, wireless frame information regarding the wireless frame in association with wireless communication device identification information for identifying a wireless communication device that is a source of the wireless frame and channel information indicating a channel used by the wireless communication device that is the source of the wireless frame. Frame capture device.

2. when the channel information is not included based on the notification from the radio frame management unit, the radio frame information storage unit identifies the channel information corresponding to the wireless communication device identification information included in the wireless frame from the channel information stored in the radio frame information storage unit, and stores the radio frame information in association with the wireless communication device identification information included in the wireless frame and the identified channel information.

2. 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.

2. The frame capture device according to claim 1.

4. The wireless communication device identification information indicates a MAC address unique to the wireless communication device of the source.

3. The frame capture device according to claim 1 or 2.

5. 1. A frame capture method for capturing wireless frames transmitted by a plurality of wireless communication devices when a plurality of types of channels are used by the wireless communication devices, the method comprising the steps of: a frequency band information storage step of storing frequency band information indicating a frequency band of each of a plurality of types of channels in association with channel information indicating the corresponding channel; a frequency conversion step of converting a signal arriving from the wireless communication device into a signal having the same frequency band as the frequency band of the first channel and outputting the signal, when the channel used by the wireless communication device is a channel different from a first channel that is preset among the plurality of types of channels stored in the frequency band information storage step; a determination step of determining whether the radio frame corresponding to the signal output by the frequency conversion step includes the channel information; a wireless frame information storage step of, when it is determined that the wireless frame includes the channel information by the determination step, storing the wireless frame information regarding the wireless frame in association with wireless communication device identification information for identifying a wireless communication device that is a source of the wireless frame and channel information indicating a channel used by the wireless communication device that is the source of the wireless frame. Frame capture method.

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