Communication device, communication method, and program thereof

Abstract

A communication device capable of detecting a network setting error is provided. [Solution] A communication device includes a transmitting means and a receiving means. The transmitting means registers interface setting information indicating whether the network setting of the device itself when it becomes a transmitting device in a data portion of a diagnostic frame, and transmits the diagnostic frame including address information indicating a receiving device to be a transmission destination to the receiving device. Upon receiving the diagnostic frame, the receiving means determines whether there is a network setting error using the interface setting information set in the data portion of the diagnostic frame and the acquired interface setting information set in the receiving device.

Description

[Technical field]

[0001] The present disclosure relates to a communication device, a communication method, and a program therefor. [Background technology]

[0002] As digital transformation (DX) advances year by year, the suspension of network infrastructure operations has become a social issue. However, there are cases where network infrastructure system configuration is performed manually. One example of something that may be configured manually is the interface between devices connected by communication. In this case, even if there is a configuration error, the problem may not surface, and may suddenly become apparent.

[0003] For example, Patent Document 1 describes a setting device that updates the settings of communication devices that make up a network while the network is running. More specifically, the device described in Patent Document 1 removes a specified communication device that is the target of the setting update from a network consisting of multiple communication devices, updates the settings of the communication device that is the target of the setting update after the removal, and returns the removed communication device to the network after the update. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-169044 A Summary of the Invention [Problem to be solved by the invention]

[0005] The device described in Patent Document 1 is a technology for updating communication devices that are subject to setting updates while the network is in operation, and is not intended to detect setting errors. Therefore, it is not capable of detecting network setting errors in communication devices included in a system configured for a network infrastructure, such as errors before the start of operation.

[0006] An object of the present disclosure is to provide a communication device, a communication method, and a program therefor that solve the above-mentioned problems. [Means for solving the problem]

[0007] A communication device according to one embodiment of the present disclosure comprises a transmitting means for registering interface setting information indicating whether the network settings of the device itself when it becomes a transmitting device in a data section of a diagnostic frame, and transmitting the diagnostic frame including address information indicating the destination receiving device to a receiving device, and a receiving means for, upon receiving the diagnostic frame, determining whether there is a network setting error using the interface setting information set in the data section of the diagnostic frame and the interface setting information set in the acquired receiving device.

[0008] A communication method according to one aspect of the present disclosure registers interface setting information indicating whether the network settings of the device itself when it becomes a transmitting device in the data section of a diagnostic frame, transmits the diagnostic frame to a receiving device, the diagnostic frame including address information indicating the destination receiving device, and upon receiving the diagnostic frame, determines whether there is a network setting error using the interface setting information set in the data section of the diagnostic frame and the interface setting information set in the obtained receiving device.

[0009] A program for a communication device according to one embodiment of the present disclosure causes a computer to register interface setting information indicating whether the network settings of the device itself when it becomes a transmitting device in the data section of a diagnostic frame, transmit the diagnostic frame including address information indicating the destination receiving device to a receiving device, and, upon receiving the diagnostic frame, determine whether there is any network setting error using the interface setting information set in the data section of the diagnostic frame and the interface setting information set in the obtained receiving device. Effect of the Invention

[0010] According to the above aspect, it becomes possible to detect a network setting error. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram showing a network configuration device according to the present disclosure. [Diagram 2] 13A and 13B are diagrams illustrating examples of configurations of a diagnostic frame and frame passing information. [Diagram 3] FIG. 13 is a diagram illustrating an example of a MAC table. [Figure 4] FIG. 11 is a diagram showing a flow of a command generation process of the transmitting device. [Diagram 5] 13 is a diagram showing the flow of frame modification processing by a frame modification unit of a Layer 2 switch when a diagnostic frame output is received. FIG. [Figure 6] 13 is a diagram showing the flow of frame modification processing by a frame modification unit of a Layer 2 switch when a diagnostic frame output is received. FIG. [Figure 7] FIG. 13 is a diagram showing the flow of a MAC table search process for searching the MAC table using a destination MAC address as a key. [Figure 8] FIG. 11 is a diagram illustrating a flow of a frame reception process. [Figure 9] FIG. 11 is a diagram illustrating a flow of a frame reception process. [Figure 10]FIG. 1 is a block diagram showing a network configuration device according to the present disclosure. [Figure 11] FIG. 13 is a diagram illustrating the configuration of a diagnostic MAC frame. [Figure 12] 11 is a diagram for explaining an operation for detecting a configuration setting error of a network interface in the configuration shown in FIG. 10. FIG. [Figure 13] 11 is a diagram for explaining an operation for detecting a configuration setting error of a network interface in the configuration shown in FIG. 10. FIG. [Figure 14] FIG. 1 is a diagram illustrating a configuration of a communication system according to the present disclosure. [Figure 15] FIG. 13 is a diagram illustrating a configuration of a diagnostic IP frame. [Figure 16] 15 is a diagram for explaining an operation for detecting a configuration setting error of a network interface in the configuration shown in FIG. 14. [Figure 17] 15 is a diagram for explaining an operation for detecting a configuration setting error of a network interface in the configuration shown in FIG. 14. [Figure 18] FIG. 1 is a diagram illustrating a configuration example of a communication device according to an embodiment of the present disclosure. [Figure 19] FIG. 2 is a block diagram showing an example of a hardware configuration of a communication device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, each embodiment will be described with reference to the drawings. In all the drawings, the same or corresponding components are denoted by the same reference numerals, and common descriptions will be omitted.

[0013] First Embodiment An embodiment of the present disclosure will be described below with reference to the drawings. FIG. 1 is a block diagram showing a network configuration device according to an embodiment of the present disclosure. The network configuration device is composed of a transmitting device (100), a receiving device (300), and a layer 2 switch (200), which is a type of communication device connected to the transmitting device (100) and the receiving device (300) by a LAN cable. In the following, the transmitting device (100) will be described as a transmitting device that transmits a diagnostic frame, which will be described separately, and the receiving device (300) will be described as a receiving device that is the destination of the diagnostic frame. Note that the transmitting device (100) can be a receiving device, and the receiving device (300) can be a transmitting device, so both devices have the same functions. Also, while FIG. 1 shows only the transmitting device (100) and the receiving device (300), the transmitting device (100) and multiple communication devices that can be the receiving device (300) can be connected to the layer 2 switch (200).

[0014] The transmitting device (100) and the receiving device (300) each include a command generating unit (101), a frame receiving unit (102), a LAN driver (103), a MAC control unit (104), and a PHY (105).

[0015] The PHY (105) is connected to a LAN cable and implements the function of the physical layer in a communication protocol. The MAC control unit (104) transmits and receives data to and from the PHY (105) and implements the function of the data link layer related to medium access control. The LAN driver (103) creates frame passing information for the data portion (F105) of a diagnostic frame (F100) described later. The LAN driver (103) also performs processing to pass the diagnostic frame (F100) to the frame receiving unit (102). The command generating unit (101) instructs the LAN driver (103) to generate an Ethernet frame for the diagnostic frame (F100). When the frame receiving unit (102) receives the diagnostic frame (F100) from the LAN driver (103), it checks the type (F104) of the diagnostic frame (F100) described later, and in the case of a diagnostic request, changes the type (F104) to a transmission reply and transmits it via the LAN driver. Furthermore, if the type (F104) of the diagnostic frame (F100) is a diagnostic reply, the frame receiving section (102) checks whether there is an error in the interface settings between the transmitting and receiving devices.

[0016] Here, the diagnostic frame (F100) and frame passing information will be described. FIG. 2 is a diagram showing an example of the configuration of the diagnostic frame (F100) and frame passing information. The diagnostic frame (F100) is composed of a preamble (F101), a destination MAC address (F102), a source MAC address (F103), a type (F104), a data section (F105), and an FCS (F106) of the frame. Here, the preamble (F101) indicates the start of an Ethernet frame in the diagnostic frame (F100). The destination MAC address (F102) indicates the MAC address of the receiving device (300). The source MAC address (F103) indicates the MAC address of the transmitting device. The type (F104) indicates that the diagnostic frame is a request from the transmitting device or a reply from the receiving device. The data section (F105) is composed of one or more pieces of frame passing information. The FCS (F106) is the frame error detection symbol (Frame Check Sequence).

[0017] The frame passing information is composed of a device number (D101), a receiving interface number (D102), interface setting information (D103), a transmitting interface number (D104), and interface setting information (D105). The device number (D101) indicates a number that uniquely identifies a device on a communication path. The receiving interface number (D102) indicates the receiving interface number of the receiving device that received the diagnostic frame. The interface setting information (D103) is receiving interface setting information that indicates information on whether the receiving interface is fixed or automatically set. The transmitting interface number (D104) indicates the receiving interface number of the transmitting device that transmits the diagnostic frame. The interface setting information (D105) is transmitting interface setting information that indicates information on whether the transmitting interface is fixed or automatically set. As described above, one or more pieces of frame passing information are registered in the data section (F105).

[0018] For the diagnostic frame (F100) described above, the LAN driver (103) reads the unit number (D101) set in the device in response to a transmission instruction from the command generating unit (101), the interface setting information (D105) of the interface set in the MAC control unit (104), and the interface number (D104) set in the LAN driver (103) when transmitting the diagnostic frame (F100), and creates frame passing information for the data section (F105) of the diagnostic frame (F100). Also, when receiving the diagnostic frame (F100), the LAN driver (103) adds the unit number (D101), the interface setting information (D103) of the interface set in the MAC control unit (104), and the interface number (D102) set in the driver as frame passing information to the data section (F105) of the diagnostic frame (F100), and passes it to the frame receiving unit (102).

[0019] The layer 2 switch (200) has a processing function for the second layer of a communication protocol, and performs switching processing of communication frames transmitted and received between the transmitting device (100) and the receiving device (300). The layer 2 switch (200) has a receiving PHY (201), a receiving MAC control unit (202), a receiving control unit (203), a frame modification unit (204), a transmission control unit (205), a transmitting MAC control unit (206), a transmitting PHY (207), and a MAC table (T200).

[0020] The receiving PHY (201) is connected to the transmitting device (100) via a LAN cable and implements a physical layer function. The receiving MAC control unit (202) receives data from the receiving PHY (201) and implements a data link layer function. The receiving control unit (203) outputs the received frame and the receiving interface number (D102) to the frame changing unit (204).

[0021] The frame modification unit (204) checks the type (F104) of the received frame, and in the case of a diagnosis request and at the time of frame transmission, determines the reception MAC control unit (202) specified by the device number (D101) set in the device and the reception interface number that received the received frame. The frame modification unit (204) then reads the interface setting information (D103) of the interface set in the specified reception MAC control unit (202). The frame modification unit (204) then searches a MAC table (T200) (to be described later) using the destination MAC address (F102) of the frame as a key to determine the interface number (D104) of the transmission destination. Furthermore, the frame modification unit (204) reads the interface setting information (D105) set in the transmission MAC control unit (206) corresponding to the determined interface number (D104), adds this information to the data portion (F105) of the frame as frame passing information, and outputs it to the transmission control unit (205).

[0022] The transmission control unit (205) outputs the frame from the frame modification unit (204) to a transmission MAC control unit (206). The transmission MAC control unit (206) implements a data link layer function and outputs the frame from the transmission control unit (205) to a transmission PHY (207). The transmission PHY (207) is connected to the receiving device (300) via a LAN cable and transmits the frame from the transmission MAC control unit (206) to the receiving device (300).

[0023] The layer 2 switch (200) has a plurality of receiving PHYs (201), receiving MAC controllers (202), receiving controllers (203), transmitting controllers (205), transmitting MAC controllers (206), and transmitting PHYs (207) for each interface. Each of the receiving controllers (203) and transmitting controllers (205) of the layer 2 switch (200) is connected to a frame modification unit (204).

[0024] Furthermore, before the network configuration devices are put into operation, the device number (D101) of each device, the transmitting device (100), the Layer 2 switch (200), and the receiving device (300), is set. The interface numbers (D102, D104) of the interfaces that transmit and receive frames are assigned to the LAN driver (103), the receiving control unit (203), and the transmitting control unit (205). The interface setting information (D103, D105), which is the setting value for the interface identified by the interface number, is set to the MAC control unit (104), the receiving MAC control unit (202), and the transmitting MAC control unit (206).

[0025] Generally, in a Layer 2 switch (200), when transmission and reception are performed between the transmitting device (100) and the receiving device (300), a MAC table (T200) is created that is made up of a MAC address (T201) and an interface number (T202) of the Layer 2 switch (200) associated with the MAC address in order to determine which interface to transfer the received frame through. Figure 3 shows an example of the MAC table (T200). As shown in the figure, the MAC table (T200) is a table that associates the MAC address (T201) with the interface number (T202).

[0026] Next, a method for detecting a configuration setting error in a network interface will be described with reference to FIGS.

[0027] 4 is a diagram showing a flow of a command generation process in which a command generation unit (101) and a LAN driver (103) of a transmitting device (100) generate a diagnostic frame (F100). When a user of the transmitting device (100) issues a command to instruct transmission of a diagnostic frame (F100) for diagnosis, the user inputs a destination MAC address (F102), which can generally be confirmed by an ARP command or the like, an interface number (D104) for transmitting the diagnostic frame (F100), and a transmission MAC address (F103) assigned to an interface of the device itself, into the command generation unit (101) as arguments for the command (S101). Here, the "ARP command" is a command for displaying / setting an ARP (Address Resolution Protocol) table, and the ARP table is a comparison table of IP addresses and MAC addresses used for Ethernet communication.

[0028] Upon receiving an input from the user, the command generation unit (101) reads the unit number set in the transmitting device (100) and the interface setting information of the interface set in the MAC control unit (104), stores the unit number of the device in variable A1 and the interface setting information in variable A2 (S102), and instructs the LAN driver (103) to generate a diagnostic frame. Next, in order to create a data section (F105) of the diagnostic frame (F100), the LAN driver (103) sets the variable A1 as the unit number (D101), sets the receiving interface number (D102) to "0xFF" which is an interface number that is not a receiving device, and sets the interface setting information (D103) to "0xFF", which is a value that is not a set value. The LAN driver (103) also sets the inputted transmitting interface number as the transmitting interface number (D104), and sets the variable A2 as the interface setting information (D105) (S103).

[0029] Next, the LAN driver (103) sets the destination MAC address in the destination MAC address (F102), the source MAC address in the source MAC address (F103), and a type defined as a diagnostic request for the diagnostic frame, for example, "0xA100," in the type (F104) of the header of the diagnostic frame (F100) (S104).The LAN driver (103) outputs the created diagnostic frame to the MAC control unit (104).

[0030] The MAC control unit (104) adds a preamble (F101) and an FCS (F106) to the diagnostic frame, and outputs the diagnostic frame (F100) from the PHY (105) to the LAN cable (S105). Note that the "FCS" (Frame Check Sequence) is a code added to the frame for error detection.

[0031] A receiving PHY (201) of the Layer 2 switch (200) receives the diagnostic frame (F100) from the transmitting device (100) via the LAN cable and outputs it to a receiving MAC control unit (202). The receiving MAC control unit (202) outputs the diagnostic frame (F100) to a receiving control unit (203). The receiving control unit (203) outputs the diagnostic frame (F100) and the received receiving interface number to a frame modification unit (204).

[0032] 5 and 6 are diagrams showing a flow of frame modification processing by the frame modification unit (204) of the layer 2 switch (200) when a diagnostic frame (F100) is output. In the frame modification processing, the frame modification unit (204) checks whether the type (F104) of the received frame is a diagnostic request (S201). If it is not a diagnostic request (S201: No), the frame is output to the transmission control unit (205) as a normal operation of the layer 2 switch (200), and the frame is output from the transmission PHY (207) via the transmission MAC control unit (206) (S202). On the other hand, if it is a diagnostic request (S201: Yes), the unit number set in the layer 2 switch (200) and the interface setting information set in the reception MAC control unit (202) corresponding to the reception interface number are read, and the unit number is set to variable A3 and the interface setting information is set to variable A4 (S203). The determination of whether or not the frame is a diagnosis request is made based on the type (F104) in the frame. The receiving interface number is the interface number of the layer 2 switch (200) to which the transmitting device (100) is connected.

[0033] Next, the frame modification unit (204) searches the MAC table (T200) using the destination MAC address (F102), and sets the transmission interface number (T202) corresponding to the destination MAC address (F102) to a variable A5 (S204). Details of the search process by the frame modification unit (204) using the MAC table (T200) will be described separately.

[0034] The frame modification unit (204) checks whether the variable A5 is set to "0xFF", which is a value indicating that the destination MAC address does not exist in the MAC table, as a result of searching the MAC table (T200) (S205). If "0xFF" is set (S205: Yes), the frame modification unit (204) performs flooding processing to transmit the diagnostic frame (F100) from all interfaces specified by the interface numbers in the layer 2 switch (200) other than the receiving interface that received the diagnostic frame from the transmitting device (100).

[0035] 6 is a diagram showing "flooding" processing by the frame modification unit (204). As described above, the layer 2 switch (200) is provided with multiple interfaces. Multiple communication devices such as the transmitting device (100) and receiving device (300) shown in FIG. 1 are connected to different interfaces of the layer 2 switch (200) via LAN cables. As described above, "flooding" processing refers to processing in which the layer 2 switch (200) outputs a diagnostic frame (F100) from all interfaces provided in the layer 2 switch (200) other than the receiving interface that received the diagnostic frame (F100) from the transmitting device (100).

[0036] For "flooding" processing, the frame modification unit (204) sets the lowest interface number of the device to variable X as shown in FIG. 6 (S210). In the example shown in FIG. 3, the lowest interface number is "1". To modify the diagnostic frame for flooding, the frame modification unit (204) reads interface setting information from the transmission MAC control unit (206) corresponding to the variable X in which the transmission interface number is set, and sets the read interface setting information to variable A7 (S212). Next, in order to create the data portion (F105) of the diagnostic frame (F100), the frame modification unit (204) sets variable A3 as the unit number (D101) of the layer 2 switch (200), sets the receiving interface number of the layer 2 switch (200) that received the diagnostic frame as the receiving interface number (D102), and sets variable A4 as interface setting information (D103). Furthermore, the frame modification unit (204) sets a variable X as the transmission interface number (D104), sets a variable A7 as the interface setting information (D105), creates frame passing information, and adds the created frame passing information to the end of the data section (F105) (S213).

[0037] Next, the frame modification unit (204) outputs the diagnostic frame (F100) to the transmission control unit (205) for transmission (S215) without modifying the destination MAC address (F102), source MAC address (F103), and type (F104) as the header of the diagnostic frame (F100). The output diagnostic frame (F100) is output from the transmission PHY (207) via the transmission control unit (205) and the transmission MAC control unit (206). In order to perform the above processes from S212 to S215 for all interfaces provided in the layer 2 switch (200), the variable X is incremented (S216) and the process proceeds to S211. If the value of the variable X matches the number of the receiving interface of the layer 2 switch (200) that received the diagnostic frame (F100) from the transmitting device (100), the frame modification unit (204) does not perform the processes from S212 to S215. Furthermore, when the frame modification unit (204) increments the variable X (S216) and determines that output of the diagnostic frame from all interfaces provided in the layer 2 switch (200) is complete, the frame modification unit (204) ends the process shown in FIG. 6 and ends the process of flooding the diagnostic frame.

[0038] Returning to Fig. 5, if the variable A5 is not 0xFF (S205: No), the frame modification unit (204) reads interface setting information from the transmission MAC control unit (206) corresponding to the variable A5 in which the transmission interface number is set, and sets the read interface setting information to the variable A6 (S206). Then, in order to create the data portion (F105) of the diagnostic frame (F100), the frame modification unit (204) sets the variable A3 as the unit number (D101) of the layer 2 switch (200), sets the receiving interface number of the layer 2 switch (200) that received the diagnostic frame as the receiving interface number (D102), and sets the variable A4 as the interface setting information (D103) corresponding to the receiving interface number. Furthermore, the frame modification unit (204) sets the variable A5 as the transmitting interface number (D104) and the variable A6 as the interface setting information (D105) to generate frame passing information. The frame modification section (204) adds the generated frame passing information to the end of the data section (F105) of the received diagnostic frame (S207).

[0039] Next, the frame modification unit (204) leaves the destination MAC address (F102), source MAC address (F103), and type (F104) unchanged (S208) as the header of the diagnostic frame (F100), and outputs the diagnostic frame to the transmission control unit (205) for transmission (S209). Under the control of the transmission control unit (205), the transmission MAC control unit (206) adds a preamble (F101) and FCS (F106), and finally causes the frame to be output from the transmission PHY (207) via the LAN cable.

[0040] In this manner, the diagnostic frame (F100) output from the transmitting device (100) is transmitted to the receiving device (300) via the layer 2 switch (200) connected to a plurality of communication devices.

[0041] Next, the search process using the MAC table (T200) will be described in detail. FIG. 7 is a diagram showing the flow of the MAC table search process (S500) for searching the MAC table (T200) using the destination MAC address (F102) as a key. When the frame modification unit (204) acquires the destination MAC address (F102) (S501), it sets the variable M to 1 to search from interface number 1 (S502). Then, the frame modification unit (204) reads the Mth variable in the interface setting table (S503) and determines whether the destination MAC address (F102) matches the MAC address (T201) set in the variable M, which is the interface number (T202) (S504). If they match (S504: Yes), the frame modification unit (204) ends the search with the interface number (T202) of the matched number as the search result (S507). If there is no match (S504: No), the frame modification unit (204) adds 1 to the variable M in order to search the next table (S505). If there is no match even after searching the end of the interface setting table for the variable M (S506: No), the frame modification unit (204) sets the search result to "0xFF", indicating a non-existent interface number (S508), and ends the search process. Note that the layer 2 switch (200) shown in Figures 5 to 7 processes diagnostic frames in both cases where the diagnostic frame (F100) is a diagnostic request and where it is a diagnostic reply.

[0042] When the PHY (105) of the receiving device (300) receives the diagnostic frame (F100) transmitted via the Layer 2 switch (200), the PHY (105) outputs the diagnostic frame (F100) to the MAC control unit (104). The MAC control unit (104) removes the preamble (F101) and FCS (F106) and outputs the frame to the LAN driver (103). The LAN driver (103) outputs the received frame together with the receiving interface number to the frame receiving unit (102).

[0043] 8 and 9 are diagrams showing the processing flow of the frame reception process (S300) by the frame receiving unit (102) and the LAN driver (103). In the diagrams, steps S301, S302, S303, S304, and S305 are processes performed when a diagnosis request is received by the receiving device (300), and steps S306, S307, S308, S309, S310, S311, S312, S313, and S315 are processes performed when a diagnosis reply is received by the transmitting device (100).

[0044] When the frame receiving unit (102) of the receiving device (300) receives a frame, it checks (S301) whether the received frame is a diagnosis request based on the type (F104) of the received frame. If the received frame is neither a diagnosis request nor a diagnosis reply (S301: No in FIG. 8, S306: No in FIG. 9), the normal receiving process is performed on the received frame (S314 in FIG. 9).

[0045] In the case of a diagnosis request (S301: Yes), the frame receiving unit (102) reads the unit number of the receiving device (300) and the interface setting information of the interface set in the MAC control unit (104) of the receiving device (300) via the LAN driver. Then, the frame receiving unit (102) sets the unit number to variable A8 and the interface setting information to variable A9 (S302). In order to create frame passing information to be registered in the data section (F105) of the diagnostic frame (F100), the LAN driver (103) sets the variable A8 as the unit number (D101), sets the receiving interface number as the receiving interface number (D102), and sets the variable A9 as the interface setting information (D103). Furthermore, the LAN driver (103) sets the interface number of a non-transmitting device, “0xFF”, as the transmitting interface number (D104), and sets the interface setting information (D105) to “0xFF”, a value not set as a setting value (S303). The LAN driver (103) sets the source MAC address of the received frame to the destination MAC address (F102) as the header of the diagnostic frame (F100), sets the destination MAC address of the received frame to the source MAC address (F103), and sets a type defined as a diagnostic reply, for example, "0xA101," to the type (F104) (S304). The LAN driver (103) outputs the diagnostic frame (F100) to the MAC control unit (104) to transmit the diagnostic frame (F100) (S305). The MAC control unit (104) adds a preamble (F101) and FCS (F106) to the diagnostic frame (F100), and outputs the diagnostic frame (F100) from the PHY (105) to the LAN cable (S305).

[0046] 9, when the frame receiving unit (102) of the transmitting device (100) judges that the reply is a diagnosis reply (S306: Yes), the frame receiving unit (102) sets a variable Y indicating which frame passing information it is (S307). The frame receiving unit (102) checks whether the variable Y-th transmitting interface number (D104) and the variable Y+1-th receiving interface number (D102) are "0xFF" indicating a non-existent interface number. If the value is "0xFF" (S308: Yes), the frame receiving unit (102) detects this as an inconsistency. If the value is not "0xFF" (S308: No), the frame receiving unit (102) compares the variable Y-th transmitting interface setting information (D105) with the variable Y+1-th receiving interface setting information (D103) (S310). If the comparison shows that the interface setting information does not match (S311: Yes), the frame receiving unit (102) detects an error as a mismatch.

[0047] On the other hand, if there is no mismatch (S311: No), the frame receiving unit (102) determines that there is a match, adds 1 to the variable Y (S312), and proceeds to check the next frame passing information. If checking of the list of frame passing information for the received diagnostic frame (F100) is complete (S313: No), the frame receiving unit (102) ends the process. Note that since the list is checked in pairs for transmission and reception, the Y-1th check will be the last check.

[0048] If there is a mismatch, the frame receiving unit (102) outputs the Yth and Y+1th frame passing information to the user (S315).

[0049] Focusing on the fact that communication is possible without being disabled even if a setting error occurs in a communication device or in a layer 2 switch (200) to which the communication device is connected, the above processing using the data portion (F105) of the frame makes it possible to detect setting errors between the layer 2 switch (200) and the communication device connected thereto. As a result, it is not necessary to prepare a setting device or a setting network, which results in the effects of cost and power saving. In addition, since the communication path to be operated can be diagnosed at once, there is also an effect in terms of cost since there is no need to log in and check each device. In addition, when a diagnostic frame passes through each device on the communication path to be operated, each device adds frame passing information to the data portion (F105) of the diagnostic frame (F100), so that it becomes possible to easily identify a mismatch in interface setting information between physically connected communication devices, in the example of FIG. 1, between the receiving device (100) and the layer 2 switch (200) and between the transmitting device (300) and the layer 2 switch (200). Furthermore, by adding the interface numbers (D102, D104) to the frame passing information, if there is a mismatch in the interface setting information, it becomes possible to easily identify which interface of the target communication device the mismatch occurs in. In addition, by adding the unit number (D101) to the frame passing information, it becomes possible to easily identify which communication device the mismatch occurs in.

[0050] <Second embodiment> As an embodiment according to the present disclosure, another method for detecting a configuration setting error in a LAN driver between devices at both ends of a LAN cable will be described. Fig. 10 is a block diagram showing a network configuration device according to the present disclosure. The network configuration device is composed of a transmitting device (400) that communicates frames, a receiving device (500) that receives frames, and a LAN cable that connects them.

[0051] The transmitting device (400) and the receiving device (500) are each composed of a PHY (405), a MAC control unit (404), a LAN driver (401), and a frame generating unit (402) and a frame receiving unit (403) provided within the LAN driver (401).

[0052] The PHY (405) is connected to a LAN cable and implements a physical layer function. The MAC control unit (404) transmits and receives data from the PHY (405) and implements a data link layer function. The LAN driver (401) controls the MAC control unit (404). The frame generation unit (402) has a function of generating and issuing an Ethernet frame of the diagnostic MAC frame (F200) in the LAN driver (401). The frame reception unit (403) has a function of performing a process of checking a destination MAC address when the diagnostic MAC frame (F200) is received from the MAC control unit (404) in the LAN driver (401). In addition, in the case of the diagnostic MAC frame (F200), the frame reception unit (403) also has a process of detecting whether there is an error in auto-negotiation and fixed interface settings between the interfaces between the transmitting and receiving devices.

[0053] FIG. 11 is a diagram showing the structure of a diagnostic MAC frame (F200). The diagnostic MAC frame (F200) is composed of a preamble (F201), a destination MAC address (F202), a source MAC address (F203), a type (F204), a data section (F205), and an FCS (F206) of the frame. Here, the preamble (F201) indicates the start of an Ethernet frame. The destination MAC address (F202) sets a multicast address defined as the diagnostic MAC frame (F200). The source MAC address (F203) indicates the MAC address of the transmitting device (400). The type (F204) indicates that it is a diagnostic MAC frame (F200). The data section (F205) includes interface setting information (D201), which is information indicating whether the interface is fixed or automatically set. Note that a multicast address is also a type of address that identifies a receiving device that is the destination of the transmission.

[0054] A method for detecting a configuration setting error in a LAN driver between devices at both ends of a LAN cable will be described. Figures 12 and 13 are diagrams for explaining the operation for detecting a configuration setting error of a network interface in the configuration shown in Figure 10. First, the flow of command generation processing in the transmitting device (400) will be described with reference to Figure 12.

[0055] Generally, a LAN driver (401) holds a MAC address and interface setting information associated with the interface of its own device, which are necessary for communication when the device is started. When the transmitting device (400) is connected to the receiving device (500) with a LAN cable, link-up is completed and communication is possible (S601), the frame generating unit (402) sets the MAC address held by the LAN driver (401) to variable B1 and the interface setting information to variable B2 (S602). The frame generating unit (402) sets the variable B2 as interface setting information (D201) in the data portion (F205) to generate a diagnostic MAC frame (F200) (S603). The frame generation unit (402) also sets the destination MAC address (F202) to a multicast address (e.g., 0180:c200:3FFF) defined as the diagnostic MAC frame (F200), sets the source MAC address (F203) to a variable B1, and sets the type (F204) to "0xA100" indicating a diagnostic request of the diagnostic MAC frame (F200) (S604). The frame generation unit (402) then outputs the generated diagnostic MAC frame (F200) to the MAC control unit (404) for outputting the generated diagnostic MAC frame (F200) (S605). The MAC control unit (404) adds a preamble (F101) and an FCS (F106) to the diagnostic MAC frame (F200). The diagnostic MAC frame (F200) is then transmitted to the LAN cable via the PHY (405).

[0056] When the receiving device (500) receives the diagnostic MAC frame (F200) at the PHY (405), the PHY (405) outputs the diagnostic MAC frame (F200) to the MAC control unit (404). The MAC control unit (404) removes the preamble (F101) and FCS (F106), and outputs the diagnostic MAC frame (F200) to the LAN driver (401). The frame receiving unit (403) of the LAN driver (401) starts frame reception processing.

[0057] 13 is a diagram showing a flow of frame reception processing by the frame receiving unit (403). If the destination MAC address (F202) does not match the defined multicast address (S701: No), the frame receiving unit (403) processes the frame as a normal frame reception (S702). On the other hand, if they match (S701: Yes), the frame receiving unit (403) extracts interface setting information from the data section (F205) and stores it in variable B3 (S703). Next, the frame receiving unit (403) stores the interface setting information of the receiving interface held as its own device in the LAN driver (401) of the receiving device (500) in variable B4 (S704), and checks whether variable B3 and variable B4 match (S705). If they do not match (S705: No), the frame receiving unit (403) outputs an error message (S706), notifies the user of a setting error, and ends the processing. If they match (S705: Yes), the frame receiving unit (403) ends the process normally.

[0058] In this manner, a configuration setting error is detected in the LAN driver between the devices on both ends of the LAN cable.

[0059] <Third embodiment> As an embodiment of the present disclosure, a method for detecting a configuration setting error between devices at both ends of a LAN cable will be described.

[0060] FIG. 14 is a block diagram showing a network configuration device according to the present disclosure. The communication system is composed of a transmitting device (600) that communicates frames, a receiving device (700) that receives frames, and a LAN cable that connects them. The transmitting device (600) and the receiving device (700) are composed of a PHY (605), a MAC control unit (604), a LAN driver (603), a command generation unit (601), and a frame receiving unit (602). The PHY (605) is connected to the LAN cable and implements a physical layer function. The MAC control unit (604) transmits and receives data from the PHY (605) and implements a data link layer function. The LAN driver (603) controls the MAC control unit (604). The command generation unit (601) generates and issues an Ethernet frame of a diagnostic IP frame (F300) to the LAN driver (603). When a frame receiving unit (602) receives a diagnostic IP frame (F300) from a LAN driver (603), it checks the destination port number (D302) in the UDP header, and in the case of a diagnostic request, detects whether there is an error in the interface settings between the transmitting and receiving devices.

[0061] FIG. 15 is a diagram showing the structure of a diagnostic IP frame (F300). The diagnostic IP frame (F300) is composed of an Ethernet frame MAC header (F301), an IP header (F302), a UDP header (F303), and UDP data (F304). Here, the IP header (F302) is an IP header defined by RFC791 that includes a destination IP address and a source IP address. Note that RFC791 is one of the documents that describes standard specifications for Internet technology. The UDP header (F303) is a header defined by RFC791, and is composed of a general source port number (D301), a destination port number (D302) that stores a number such as 0x3011 defined as a diagnostic request, a segment length (D303), and a checksum (D304). The UDP data (F304) includes interface setting information (D305) that is information on whether the interface is fixed or automatically set.

[0062] A method for detecting a configuration setting error between devices at both ends of a LAN cable will be described. Figures 16 and 17 are diagrams for explaining the operation for detecting a configuration setting error of a network interface in the configuration shown in Figure 14. First, with reference to Figure 16, the flow of a command generation process for generating a diagnostic IP frame (F300) in a command generation unit (601) of a transmitting device (600) will be described.

[0063] 16, in order to issue a command to instruct the user to send a diagnostic IP frame (F300) for diagnosis, the user inputs as arguments a destination port number (D302) defined as a diagnostic request, a destination IP address which is the IP address of the receiving interface of the receiving device, and a source IP address which is the IP address of the transmitting interface of the device (S801), thereby starting operation. The command generation unit (601) that receives the input reads the MAC control unit (604) to which the source IP address is assigned using a general IOCTL function or the like, reads the interface setting information, and stores it in a variable C1 (S802). Here, the IOCTL function is a function for controlling a device.

[0064] Next, the LAN driver (603) sets a variable C1 in the interface setting information (D305) to create UDP data (F304) of the diagnostic IP frame (F300) (S803). The LAN driver (603) then sets an arbitrary source port number (D301) and a port number defined as a diagnostic request, for example, "0x3011", as the destination port number (D302) in the UDP header (F303) of the diagnostic IP frame (F300), and further sets the segment length (D303) and checksum (D304) (S804). The LAN driver (603) creates an IP header (F302) using the input destination IP address and source IP address, adds a MAC header (F301) (S805), and transmits the diagnostic IP frame (F300) to the MAC control unit (604) (S806).

[0065] The diagnostic IP frame (F300) is transmitted via the PHY (605) under the control of the MAC control unit (604).

[0066] 17 is a diagram showing the processing flow of frame reception processing. When the frame reception unit (602) of the receiving device (700) receives a frame, it checks (S901) whether the destination port number (D302) of the received frame is a diagnosis request. If it is not a diagnosis request (S901: No), the frame reception unit (602) performs normal frame reception processing (S902).

[0067] In the case of a diagnosis request (S901: Yes), the frame receiving unit (602) uses a general IOCTL function or the like to read the MAC control unit (604) to which the destination IP address, which is the IP address of the receiving interface, is assigned, reads the interface setting information, and sets the result to variable C2 (S903). The frame receiving unit (602) extracts interface setting information (D305) from the UDP data of the received diagnosis IP frame (F300) and sets it to variable C3 (S904). Then, the frame receiving unit (602) checks whether variable C2 and variable C3 are equal (S905), and if they are not equal (S905: Yes), it outputs an error message (S906) and ends the process. If they are equal (S905: No), the frame receiving unit (602) ends the process as normal.

[0068] In this manner, a configuration setting error is detected in the LAN driver between the devices on both ends of the LAN cable.

[0069] <Fourth embodiment> 18 is a diagram showing an example of the configuration of a communication device according to an embodiment of the present disclosure. The communication device (10) includes a transmission means (11) and a reception means (12). The transmission means (11) registers interface setting information, which indicates whether the network setting of the device itself is automatic or fixed when it becomes a transmission device, in the data portion of a diagnostic frame, and transmits the diagnostic frame, which includes address information indicating the reception device to which the diagnostic frame is to be sent, to the reception device. Upon receiving the diagnostic frame, the reception means (12) uses the interface setting information set in the data portion of the diagnostic frame and the obtained interface setting information set in the reception device to determine whether there is a network setting error.

[0070] FIG. 19 is a block diagram showing an example of a hardware configuration of a communication device (1). Here, the communication device (1) refers to a transmitting device (100), a layer 2 switch (200), a receiving device (300), a transmitting device (400), a receiving device (500), a transmitting device (600), and a receiving device (700). The control unit (2) of the communication device (1) is composed of a central processing unit (CPU) (21), a read only memory (ROM) (22), a recording device (23), a random access memory (RAM) (24), and the like. The ROM (22) and the recording device (23) record computer programs and the like that realize the functions of the communication device (1). The RAM (24) is used as a working area or the like for temporarily storing data and the like used by the CPU (21) during operation. The communication device (1) includes a PHY (4). The PHY (4) corresponds to the PHY (105), the receiving PHY (201), the transmitting PHY (207), the PHY (405), and the PHY (605). The communication device (1) may also include an input / output port (5) for connecting an input / output device such as a keyboard, a mouse, or a display device. These are connected by a bus or the like. The ROM may be configured with an EEPROM (Electrically Erasable Programmable Read-Only Memory) so that the computer program for realizing the functions of the control unit (2) can be updated. The recording device (23) may be a hard disk, an SSD, or the like, and similarly, the computer program for realizing the functions of the control unit (2) may be updated.

[0071] As described above in the present disclosure, it becomes possible to detect network setting errors in communication devices included in a system configured for a network infrastructure.

[0072] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-mentioned embodiments. Various modifications that can be understood by a person skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be appropriately combined with other embodiments.

[0073] A part or all of the above-described embodiments may be described as, but is not limited to, the following supplementary notes.

[0074] (Appendix 1) a transmitting means for registering interface setting information, which indicates whether the network setting of the device itself is automatic or fixed when the device becomes a transmitting device, in a data portion of a diagnostic frame, and transmitting the diagnostic frame, which includes address information indicating a receiving device as a transmission destination, to the receiving device; a receiving means for determining whether or not there is a network setting error when the diagnostic frame is received, by using the interface setting information set in the data portion of the diagnostic frame and the acquired interface setting information set in the receiving device; A communication device comprising:

[0075] (Appendix 2) the transmitting means includes means for registering interface setting information, which indicates whether a network setting of the own device when it becomes the transmitting device is automatic or fixed, in the data section as transmission interface setting information; the receiving means further includes means for registering the interface setting information set in the own device when the device becomes the receiving device as receiving interface setting information in the data section, and transmitting the diagnostic frame to the transmitting device; the receiving means determines whether or not there is a setting error based on the transmission interface setting information and the reception interface setting information registered in the data portion of the diagnostic frame from the transmitting device. 2. The communication device of claim 1.

[0076] (Appendix 3) the transmitting means further registers an interface number of the own device when it becomes the transmitting device as a transmission interface number in the data section; the receiving means further registers, in the data section, an interface number of the own device when it becomes the receiving device, as a receiving interface number; 3. A communication device as described in claim 2.

[0077] (Appendix 4) a plurality of pieces of frame passing information including the receiving interface number, the receiving interface setting information, the transmitting interface number, and the transmitting interface setting information can be registered in the data portion; the transmitting means registers frame passing information in which the transmission interface number and the transmission interface setting information are set, as first frame passing information in the data portion; the receiving means registers frame passing information in which the receiving interface number and the receiving interface setting information are set, as second frame passing information in the data section separately from the first frame passing information; 4. The communication device of claim 3.

[0078] (Appendix 5) the transmitting means sets a type of the diagnostic frame to a type indicating a request for a diagnostic frame when transmitting the diagnostic frame to the receiving device; the receiving means sets the type to a type indicating a reply of the diagnostic frame when transmitting the diagnostic frame to the transmitting device. 5. A communication device according to any one of Supplementary Note 2 to Supplementary Note 4.

[0079] (Appendix 6) a frame modification means for, when receiving the diagnostic frame from the communication device, specifying an interface number for the receiving device using the address information of the receiving device in the diagnostic frame, using a table in which address information of the communication device corresponds to an interface number for the communication device, modifying the diagnostic frame so as to transfer the diagnostic frame to the receiving device using the specified interface number, additionally registering interface setting information of the interface that received the diagnostic frame as receiving interface setting information in the data section, and further additionally registering interface setting information relating to the specified interface number in the data section as transmitting interface setting information; a transmitting means for transmitting the diagnostic frame modified by the frame modifying means to a receiving device as a destination; A communication device having a switch function comprising:

[0080] (Appendix 7) the frame modification means, when there is no interface number corresponding to the address information of the receiving device of the diagnostic frame in the table, modifies the diagnostic frame so that the diagnostic frame can be flooded with an interface number other than the interface number for the transmitting device registered in the table for transmission of the diagnostic frame; The transmitting means transmits the diagnostic frame modified for the flooding. 7. The communication device of claim 6.

[0081] (Appendix 8) A communication device including the communication device according to supplementary claim 2 and the communication device according to supplementary claim 6 as network component devices.

[0082] (Appendix 11) registering interface setting information, which indicates whether the network setting of the own device when it becomes a transmitting device is automatic or fixed, in a data portion of a diagnostic frame, and transmitting the diagnostic frame, which includes address information indicating a receiving device to be a transmission destination, to the receiving device; When the diagnostic frame is received, the interface setting information set in the data portion of the diagnostic frame and the acquired interface setting information set in the receiving device are used to determine whether there is a network setting error. Communication methods.

[0083] (Appendix 12) registering interface setting information, which indicates whether the network setting of the own device when it becomes the transmitting device is automatic or fixed, as transmission interface setting information in the data section; registering the interface setting information to be set in the own device when it becomes the receiving device in the data section as receiving interface setting information, and transmitting the diagnostic frame to the transmitting device; determining whether or not there is a setting error based on the transmission interface setting information and the reception interface setting information registered in the data portion of the diagnostic frame from the transmitting device; 12. The communication method according to claim 11.

[0084] (Appendix 13) an interface number of the own device when it becomes the transmitting device is further registered in the data section as a transmitting interface number; an interface number of the own device when it becomes the receiving device is further registered in the data section as a receiving interface number; 13. The communication method according to claim 12.

[0085] (Appendix 14) a plurality of pieces of frame passing information including the receiving interface number, the receiving interface setting information, the transmitting interface number, and the transmitting interface setting information can be registered in the data portion; registering frame passing information in which the transmission interface number and the transmission interface setting information are set, as first frame passing information in the data portion; registering frame passing information in which the receiving interface number and the receiving interface setting information are set, as second frame passing information in the data portion separately from the first frame passing information; 14. The communication method according to claim 13.

[0086] (Appendix 15) When transmitting the diagnostic frame to the receiving device, a type of the diagnostic frame is set to a type indicating a request for a diagnostic frame; when transmitting the diagnostic frame to the transmitting device, the type is set to a type indicating a reply of the diagnostic frame. 15. A communication method according to any one of Supplementary Note 12 to Supplementary Note 14.

[0087] (Appendix 16) a communication device according to any one of supplements 2 to 5, when receiving the diagnostic frame from the communication device, using a table in which address information of a communication device corresponds to an interface number for the communication device, identifying an interface number for the receiving device using the address information of the receiving device in the diagnostic frame, modifying the diagnostic frame so as to transfer the diagnostic frame to the receiving device using the identified interface number, additionally registering interface setting information of the interface that received the diagnostic frame as receiving interface setting information in the data section, and further additionally registering interface setting information relating to the identified interface number in the data section as transmitting interface setting information; transmitting the diagnostic frame modified by the frame modification means to a receiving device that is a destination of the diagnostic frame; A communication method in a communication device having a switch function comprising:

[0088] (Appendix 17) if there is no interface number corresponding to the address information of the receiving device in the diagnostic frame in the table, modifying the diagnostic frame so that the diagnostic frame can be flooded with an interface number other than the interface number for the transmitting device registered in the table for transmission of the diagnostic frame; transmitting the diagnostic frame modified for the flooding; 17. The communication method according to claim 16.

[0089] (Appendix 21) registering interface setting information, which indicates whether the network setting of the own device when it becomes a transmitting device is automatic or fixed, in a data portion of a diagnostic frame, and transmitting the diagnostic frame, which includes address information indicating a receiving device to be a transmission destination, to the receiving device; When the diagnostic frame is received, the interface setting information set in the data portion of the diagnostic frame and the acquired interface setting information set in the receiving device are used to determine whether there is a network setting error. A program for a communication device that causes a computer to execute the following:

[0090] (Appendix 22) registering interface setting information, which indicates whether the network setting of the own device when it becomes the transmitting device is automatic or fixed, as transmission interface setting information in the data section; registering the interface setting information to be set in the own device when it becomes the receiving device in the data section as receiving interface setting information, and transmitting the diagnostic frame to the transmitting device; determining whether or not there is a setting error based on the transmission interface setting information and the reception interface setting information registered in the data portion of the diagnostic frame from the transmitting device; 22. The program according to claim 21.

[0091] (Appendix 23) an interface number of the own device when it becomes the transmitting device is further registered in the data section as a transmitting interface number; an interface number of the own device when it becomes the receiving device is further registered in the data section as a receiving interface number; 23. The program according to claim 22.

[0092] (Appendix 24) a plurality of pieces of frame passing information including the receiving interface number, the receiving interface setting information, the transmitting interface number, and the transmitting interface setting information can be registered in the data portion; registering frame passing information in which the transmission interface number and the transmission interface setting information are set, as first frame passing information in the data portion; registering frame passing information in which the receiving interface number and the receiving interface setting information are set, as second frame passing information in the data portion separately from the first frame passing information; 24. The program according to claim 23.

[0093] (Appendix 25) When transmitting the diagnostic frame to the receiving device, a type of the diagnostic frame is set to a type indicating a request for a diagnostic frame; when transmitting the diagnostic frame to the transmitting device, the type is set to a type indicating a reply of the diagnostic frame. 25. A program according to any one of claims 22 to 24.

[0094] (Appendix 26) a communication device according to any one of supplements 2 to 5, when receiving the diagnostic frame from the communication device, using a table in which address information of a communication device corresponds to an interface number for the communication device, identifying an interface number for the receiving device using the address information of the receiving device in the diagnostic frame, modifying the diagnostic frame so as to transfer the diagnostic frame to the receiving device using the identified interface number, additionally registering interface setting information of the interface that received the diagnostic frame as receiving interface setting information in the data section, and further additionally registering interface setting information relating to the identified interface number in the data section as transmitting interface setting information; transmitting the diagnostic frame modified by the frame modification means to a receiving device that is a destination of the diagnostic frame; A program for a communication device with a switch function that causes a computer to execute the following:

[0095] (Appendix 27) if there is no interface number corresponding to the address information of the receiving device in the diagnostic frame in the table, modifying the diagnostic frame so that the diagnostic frame can be flooded with an interface number other than the interface number for the transmitting device registered in the table for transmission of the diagnostic frame; transmitting the diagnostic frame modified for the flooding; 27. The program according to claim 26. [Explanation of symbols]

[0096] 1. Communications equipment 2. Control section 4 PHY 5 Input / Output Ports 100 Transmitting device 101 Command Generation Unit 102 Frame receiver 103 LAN Driver 104 MAC control unit 105 PHY 200 Layer 2 Switch 201 Receiving PHY 202 Receiving MAC control unit 203 Reception control section 204 Frame Change Section 205 Transmission control section 206 Transmission MAC control section 207 Transmission PHY 300 Receiving device 400 Transmitting device 401 LAN Driver 402 Frame Generator 403 Frame receiver 404 MAC control section 405 PHY 500 Receiving device 600 Transmitting device 601 Command Generation Unit 602 Frame receiving section 603 LAN Driver 604 MAC control section 605 PHY 700 Receiving device

Claims

1. a transmitting means for setting interface setting information, which indicates whether a network setting of the own device is automatic or fixed, in a diagnostic frame, and transmitting the diagnostic frame, which includes address information, which indicates a destination communication device, to the destination communication device; a receiving means for determining whether there is a network setting error by comparing the interface setting information set in the received diagnostic frame with interface setting information set in the communication device that received the diagnostic frame; A communication device comprising:

2. The diagnostic frame comprises a data portion, the transmitting means includes means for registering interface setting information, which indicates whether a network setting of the own device when it becomes a transmitting device is automatic or fixed, in the data section as transmission interface setting information; the receiving means further includes means for registering the interface setting information set in the own device when the device becomes the receiving device as receiving interface setting information in the data section, and transmitting the diagnostic frame to the transmitting device; the receiving means determines whether or not there is a setting error by comparing the transmission interface setting information registered in the data portion of the diagnostic frame from the transmitting device with the reception interface setting information. The communication device according to claim 1 .

3. the transmitting means further registers an interface number of the own device when it becomes the transmitting device as a transmission interface number in the data section; the receiving means further registers, in the data section, an interface number of the own device when it becomes the receiving device, as a receiving interface number; The communication device according to claim 2 .

4. a plurality of pieces of frame passing information including the receiving interface number, the receiving interface setting information, the transmitting interface number, and the transmitting interface setting information can be registered in the data portion; the transmitting means registers frame passing information in which the transmission interface number and the transmission interface setting information are set, as first frame passing information in the data portion; the receiving means registers frame passing information, in which the receiving interface number and the receiving interface setting information are set, as second frame passing information in the data portion separately from the first frame passing information; The communication device according to claim 3.

5. the transmitting means sets a type of the diagnostic frame to a type indicating a request for a diagnostic frame when transmitting the diagnostic frame to the receiving device; the receiving means sets the type to a type indicating a reply of the diagnostic frame when transmitting the diagnostic frame to the transmitting device. The communication device according to claim 2 .

6. 3. A communication device according to claim 2, comprising: a frame modifying means for, when receiving the diagnostic frame from the communication device, specifying an interface number for the receiving device using the address information of the receiving device in the diagnostic frame, using a table in which address information of the communication device corresponds to an interface number for the communication device, modifying the diagnostic frame so as to transfer the diagnostic frame to the receiving device using the specified interface number, additionally registering interface setting information of the interface that received the diagnostic frame as receiving interface setting information in the data section, and further additionally registering interface setting information relating to the specified interface number in the data section as transmitting interface setting information; a transmitting means for transmitting the diagnostic frame modified by the frame modifying means to a receiving device as a destination; A communication device having a switch function comprising:

7. the frame modification means, when there is no interface number corresponding to the address information of the receiving device of the diagnostic frame in the table, modifies the diagnostic frame so that the diagnostic frame can be flooded with an interface number other than the interface number for the transmitting device registered in the table for transmission of the diagnostic frame; The transmitting means transmits the diagnostic frame modified for the flooding. The communication device according to claim 6.

8. A communication device comprising the communication device according to claim 2 and the communication device according to claim 6 as network component devices.

9. setting interface setting information indicating whether the network setting of the own device is automatic or fixed in a diagnostic frame, and transmitting the diagnostic frame including address information indicating the destination communication device to the destination communication device; determining whether there is a network setting error by comparing the interface setting information set in the received diagnostic frame with interface setting information set in the communication device that received the diagnostic frame; Communication methods.

10. setting interface setting information indicating whether the network setting of the own device is automatic or fixed in a diagnostic frame, and transmitting the diagnostic frame including address information indicating the destination communication device to the destination communication device; determining whether there is a network setting error by comparing the interface setting information set in the received diagnostic frame with interface setting information set in the communication device that received the diagnostic frame; A program for a communication device that causes a computer to execute the following:

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