JP2014068133A - Health check system and health check method - Google Patents

Abstract

Provided is a health check system in which a set of communication devices connected by a transmission path including a plurality of lines can execute a health check of the communication apparatus and the transmission path.
Means for generating a health check packet when a non-health check packet from a first network is not received for a first time from the last reception, and first data for converting the packet group into a transmission line frame group A first communication device comprising: a link means; a demultiplexer that distributes the frame group to a plurality of lines and transmits; a multiplexer that multiplexes a frame group received from the plurality of lines included in the transmission path; A second data link means for extracting the packet group from the packet, and a means for determining that a communication abnormality has occurred when the health check packet is deleted from the packet group and no packet group is received for the second time since the packet group was last received. And a means for transmitting the packet group to the second network.
[Selection] Figure 2

Description

  The present invention relates to a health check system, a communication device, and a health check method for communication, and in particular, a health check that executes a health check of a set of communication devices and transmission paths connected by a transmission path including a plurality of lines. The present invention relates to a system, a communication device, and a health check method.

  The health check system is a system that monitors the alive state and the operating state of the functional elements constituting the system. Examples of functional elements constituting the system include a router, a switch, a server, and a transmission path that constitute the network system. The health check includes, for example, an echo request notification (Echo Message) and an echo of ICMP (Internet Control Message Protocol) which is a protocol used for notification of an error in datagram processing of the Internet protocol, notification of information on communication, and the like. Packets such as a response notification (Echo Reply Message) (hereinafter, packets transmitted and received for the purpose of health check are referred to as “health check packets”, and packets other than health check packets are referred to as “non-health check packets”). .

  If the monitoring device periodically transmits an echo request notification to the monitoring target device and can receive an echo response notification from the monitoring target device within a certain time, it can be determined that the monitoring target device is operating normally. On the other hand, if the monitoring device cannot receive the echo response notification within a certain time, it can be determined that the monitoring target device is not operating normally. If the network system administrator knows that the monitored device is not operating normally, he can take appropriate measures.

  Even when a large number of packets are transmitted from a specific monitoring target device and a health check packet cannot be transmitted, it is desirable that the health check system has high reliability.

  Further, when the health check packet increases, the network load increases. It is desirable that the health check system can suppress an increase in network load.

  An example of a health check system is disclosed in Patent Document 1. The health check system of Patent Document 1 includes an NMS (Network Management System), one or more NEs (Network Elements), and a network connecting them. The NMS includes a non-health check packet processing unit that is a generic name for modules that process non-health check packets, and a communication state determination unit that is a module that determines a communication state between the NMS and the NE based on packets from the NE. Prepare. The NE includes a non-health check packet generator that is a generic name of modules that generate non-health check packets, a health check packet generator that is a module that generates health check packets triggered by input from the timer, and a timer. . The health check system operates as follows.

  When a non-health check packet is sent from the non-health check packet generator to the NMS, the non-health check packet generator sends a reset signal to the timer. On the other hand, inside the NMS, the communication state determination unit determines the communication state between the NMS and the NE for all NEs. That is, when neither a health check packet nor a non-health check packet is sent from a specific NE for a predetermined period, it is determined that the communication state between this NE and the NMS is abnormal.

  As a result of the above operation, this health check system can realize high reliability and suppression of an increase in network load in the health check performed by the NMS on the NE. The reason is that even if a large number of packets are sent from a specific NE and the health check packet cannot be sent, the communication state can be managed accurately, and the NE can send only the minimum necessary health check packet to the network. This is because the network load is not increased, so that an increase in network load can be suppressed.

JP-A-11-163839 (page 3-4, FIG. 2)

  In the technique disclosed in Patent Literature 1, there is a problem that an NMS connected to the NE via a network is necessary in addition to the NE in order to execute the health check of the NE.

  If the maintenance line can be used separately from the line that can be used by the transmission system before the operation of the transmission system, for example, the NMS centrally sets the settings of the NEs that configure the transmission system using the maintenance line.・ Can be managed. However, in particular, in a long-distance transmission system using submarine cables, microwaves, optical fibers, or the like, it may be difficult to prepare a maintenance line separately from the transmission line that can be used by the transmission system.

  Further, the transmission path of the transmission system may include a plurality of lines. For example, multiple wavelengths (wavelength division multiplexing, space division multiplexing, frequency division multiplexing, polarization division multiplexing, etc.) are multiplexed for microwave wavelengths, polarized waves, optical wavelengths, and multiple cables and fibers. At this time, the number of lines to be used must match between a pair of communication devices included in the transmission system.

  If it is difficult to prepare a maintenance line, NMS or the like cannot centrally set the same number of lines in each of the pair of communication devices before the operation of the transmission system. For this reason, a different number of lines may be set for each of the pair of communication apparatuses, and communication between the pair of communication apparatuses may not be performed normally. If user data (non-health check packet) is constantly transmitted between a pair of communication devices, the reception-side communication device cannot receive user data and detect a failure in the transmission-side communication device or transmission path. Can do. However, in practice, user data is generated irregularly, and therefore there may be a time during which no user data is generated. In the meantime, even if a different number of lines is set for each of the pair of communication devices included in the transmission system and the pair of communication devices cannot communicate normally, the transmission system cannot detect the abnormality (this abnormal The condition is called “silent failure”). In addition, when a failure of the transmission side communication device or transmission path is detected due to an abnormality in data reception at the reception side communication device, it is included in the failure of the transmission side communication device or the transmission path while data transmission does not occur. There is a problem that even if a pair of communication devices cannot communicate normally due to a line abnormality or the like, the transmission system cannot detect the abnormality.

  An object of the present invention is that a set of communication devices connected by a transmission path including a plurality of lines can execute a health check of the communication apparatus and the transmission path, have high reliability related to the health check, and a network related to the health check To provide a health check system, a communication device, and a health check method capable of suppressing an increase in load.

  The health check system according to the present invention includes a receiving unit that receives a frame group from a first network and extracts a first packet group that includes only non-health check packets, and a non-health check packet from the first network last. When a non-health check packet is not received for the first time after reception, the health check packet generation means for generating a health check packet, the first packet group, and the health check packet include one or more lines First data link means for converting to a transmission line frame group for a predetermined transmission line, and a first line that is the number of lines to which the transmission line frame group is distributed and transmitted among the transmission line lines A first line number setting means for setting the number of transmission lines, and a demultiplexer for distributing the transmission path frame group to the first number of lines and transmitting it to the transmission lines. A first communication device comprising: a multiplexer; a multiplexer that receives a transmission path frame group from the transmission path and multiplexes a second number of lines that is the number of lines to be multiplexed; Second line number setting means for setting the number of lines, second data link means for extracting the second packet group from the multiplexed frame group, and health check packets from the second packet group from the transmission line And a health check packet detection means for determining that a communication abnormality has occurred when the second packet group is not received for the second time since the second packet group was last received, Transmission means for converting the packet group into a frame group for the second network and transmitting the frame group.

  The communication apparatus of the present invention receives a frame group from the first network, receives a first packet group including only non-health check packets, and finally receives the non-health check packet from the first network. After that, when the non-health check packet is not received for the first time, the health check packet generating means for generating the health check packet, the non-health check packet group, and the health check packet are predetermined including one or more lines. First data link means for converting to a transmission path frame group for the transmission path, and, among the transmission path lines, the first number of lines that is the number of lines to which the transmission path frame group is distributed and transmitted And a demultiplexer that distributes the transmission path frame group to the first number of lines and transmits it to the transmission line. And.

  The communication device according to the present invention includes a first packet group including only non-health check packets and health generated when the non-health check packet is not received for a first time since the last non-health check packet was received. A transmission line frame group for a predetermined transmission line including one or more lines converted from the check packet is received, and a second number of lines, which is the number of lines to be multiplexed, is multiplexed. A second line number setting means for setting the second number of lines, a second data link means for extracting the second packet group from the multiplexed frame group, and a second line from the transmission line When the health check packet is deleted from the packet group and the second packet group is not received for the second time after the second packet group is last received, it is determined that a communication abnormality has occurred. A scan check packet detecting means, characterized in that it comprises transmission means for transmitting by converting the second packet group to the group of frames to the second network.

  The health check method of the present invention receives a frame group from a first network, extracts a first packet group including only non-health check packets, and finally receives a non-health check packet from the first network. When a non-health check packet is not received for a preset first time, a health check packet is generated, and the non-health check packet group and the health check packet are used for a predetermined transmission line including one or more lines. The transmission path frame group is distributed to the first number of lines set in advance, transmitted to the transmission path, and the transmission path frame group is received from the transmission path. Multiplex a second number of lines, which is a preset number of lines to be multiplexed, and take out the second packet group from the multiplexed frame group, When the health check packet is deleted from the second packet group from the transmission path, and the second packet group is not received for a preset second time since the second packet group was last received, It is determined that a communication abnormality has occurred, and the second packet group is converted into a frame group for the second network and transmitted.

  According to the present invention, a set of communication devices connected by a transmission path including a plurality of lines can execute a health check of the communication apparatus and the transmission path, and have high reliability related to the health check, and a network related to the health check Increase in load can be suppressed.

It is a block diagram which shows the structure of the health check system in one Embodiment of this invention, and a communication apparatus. It is a block diagram which shows the structure of a communication apparatus provided with the minimum component in one Embodiment of this invention, and a health check system using the same. It is a sequence chart explaining operation | movement of the health check system in one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

  FIG. 1 is a block diagram illustrating a configuration of a health check system and a communication device according to an embodiment of the present invention.

  The health check system of the present embodiment includes a communication device A100, a communication device B200, a transmission path 500, a network C300, and a network D400. The reference numerals of the communication devices A and B and the networks C and D are omitted hereinafter.

  The network C may be a LAN (Local Area Network) or a WAN (Wide Area Network). The network C includes Ethernet (registered trademark), TCP / IP (Transmission Control Protocol / Internet Protocol), X. It may be realized using a protocol such as 25.

  Network D is a network similar to network C.

  The transmission path 500 is a transmission path that connects the network C and the network D. The transmission line 500 can include one or more lines. The number of lines constituting the transmission line 500 may be dynamically set according to network traffic between the network C and the network D, for example. A multiplexing method such as time division multiplexing, wavelength division multiplexing, space division multiplexing, frequency division multiplexing, polarization division multiplexing, code division multiplexing, or the like may be used for the lines constituting the transmission path 500.

  The communication device A is connected to the network C and the transmission line 500.

  The communication apparatus A includes a receiving unit 110, a data link unit 120, a demultiplexer 130, a line number setting unit 140, a health check packet generation unit 150, and a packet insertion time setting unit 160.

  The receiving unit 110 receives one or more frames (hereinafter referred to as “frame group”) from the network C, and includes a “non-health check packet group” including at least one non-health check packet from the received frame group. Take out.

  The health check packet generation unit 150 passes the non-health check packet group to the data link unit 120. The health check packet generation means 150 immediately sends a health check packet when a non-health check packet group is not delivered even after a preset insertion time has elapsed since the last non-health check packet group was delivered. Generated and passed to the data link means 120. The health check packet may use ICMP echo request notification and echo response notification, CLNP (Connection Less Network Protocol), or a unique protocol.

  The packet insertion time setting unit 160 sets the above-described insertion time, which is the time from when the health check packet generation unit 150 finally passes the non-health check packet group to when the health check packet is generated. The insertion time may be fixed, and when the insertion time is fixed, the packet insertion time setting means 160 can be omitted.

  The data link means 120 establishes a data link with the communication apparatus B 200 and converts the received non-health check packet group and health check packet into a frame group for the transmission path 500. The data link means 120 may add an error detection code or the like so that a data error of a frame to be transmitted to the transmission line 500 can be detected.

  The demultiplexer 130 uses a plurality of lines having a preset number of transmission lines among the lines constituting the transmission line 500 to transfer a frame group for the transmission line 500 to the plurality of lines constituting the transmission line 500. Distribution (also referred to as demultiplexing) and transmission. A demultiplexer that performs demultiplexing is sometimes referred to as a demultiplexer.

  The line number setting means 140 sets the number of transmission lines used by the demultiplexer 130 for transmission.

  On the other hand, the communication device B is connected to the network D and the transmission path 500.

  The communication apparatus B includes a transmission unit 210, a data link unit 220, a multiplexer 230, a line number setting unit 240, a health check packet detection unit 250, and a packet detection time setting unit 260.

  The multiplexer 230 multiplexes (also referred to as demultiplexing) a frame group for the transmission line 500 received from a plurality of lines having a preset number of reception lines, and converts it into a frame group on one line. A multiplexer that performs demultiplexing is sometimes called an inverse demultiplexer.

  The line number setting means 240 sets the number of received lines that the multiplexer 230 multiplexes.

  The data link means 220 establishes a data link with the communication apparatus A100, extracts a non-health check packet and a health check packet from the frame group, and includes one or more packets (hereinafter referred to as a non-health check packet or a health check packet). (Received packet group). Note that the data link means 220 may check whether a data error has occurred in each frame.

  The health check packet detection unit 250 passes the non-health check packet among the packets included in the received packet group to the transmission unit 210 and discards the health check packet.

  The health check packet detection means 250 monitors the reception of the packets included in the received packet group, and if no packet is received within a preset detection time from the last packet reception, It is determined that a communication abnormality has occurred on the path 500.

  The packet detection time setting means 260 sets the above detection time, which is the time from when the health check packet detection means 250 determines that an abnormality has occurred since the last packet reception. The detection time may be fixed, and when the detection time is fixed, the packet detection time setting means 260 can be omitted.

  The transmission unit 210 converts the packet (including only the non-health check packet) passed from the health check packet detection unit 250 into a frame group of the network D and transmits it to the network D. The transmission medium conversion unit 210 may add an error detection code so that a data error in a frame transmitted to the network D can be detected.

  Next, the operation of this embodiment will be described.

  FIG. 3 is a sequence chart for explaining the operation of the health check system in the present embodiment. However, here, among the functional elements of the communication apparatus A, the health check packet generation unit 150 and the data link unit 120 are illustrated, and other functional elements are omitted. Here, among the functional elements of the communication apparatus B, the health check packet detecting unit 250 and the data link unit 220 are illustrated, and other functional elements are omitted.

  Here, the communication apparatus A receives the non-health check packet from the network C, and then the transmission of the non-health check packet from the network C stops. Thereafter, the health check packet transmitted from the communication apparatus A to the communication apparatus B Explain the case of loss.

  It is assumed that T1 seconds is set in the health check packet generation unit 150 by the packet insertion time setting unit 160 as the timeout time. The timeout time T1 is the time from when the health check packet generation unit 150 last receives a non-health check packet from the network C until the health check packet is inserted, or the health check packet generation unit 150 lasts the health check packet. This is the time from the insertion to the next health check packet.

  It is assumed that T2 seconds is set in the health check packet detection unit 250 by the packet detection time setting unit 260 as the timeout time. The timeout time T2 is a time from when the health check packet detection unit 250 last receives a non-health check packet or a health check packet from the communication device A until it determines a communication abnormality. Usually, a time longer than several times the time-out time T1 seconds is set as the time-out time T2 seconds.

  When the health check packet generation unit 150 receives the non-health check packet from the network C via the reception unit 110, the health check packet generation unit 150 resets the timer (step S151) and passes the non-health check packet to the data link unit 120 (step S152). ).

  When receiving the non-health check packet from the health check packet generation unit 150 (step S121), the data link unit 120 transmits the non-health check packet to the transmission line 500 via the demultiplexer 130 (step S122).

  Here, the demultiplexer 130 determines a set of lines to be used for data transmission from the network C among the lines included in the transmission line 500 according to the number of lines set by the line number setting means 140.

  When the data link means 220 receives the non-health check packet from the transmission line 500 via the multiplexer 230 (step S221), it passes the non-health check packet to the health check packet detection means 250 (step S222).

  Here, the multiplexer 230 determines a set of lines to be used for data reception from the network C among the lines included in the transmission line 500 according to the number of lines set by the line number setting unit 240.

  When receiving the non-health check packet from the data link unit 220, the health check packet detection unit 250 resets the timer (step S251) and transmits the non-health check packet to the network D via the transmission unit 210 (step S251). S252).

  Even when the communication apparatus A receives a non-health check packet from the network C before the time-out, the operations in steps S153 to S254 similar to the above steps S151 to S252 are repeated.

  If the timer of the communication device A times out before receiving the non-health check packet from the network C, the health check packet generation unit 150 resets the timer and passes the health check packet to the data link unit 120 (step S155).

  When the data link unit 120 receives the health check packet from the health check packet generation unit 150 (step S125), the data link unit 120 transmits the health check packet to the transmission line 500 via the demultiplexer 130 (step S126).

  When the data link means 220 receives the health check packet from the transmission line 500 via the multiplexer 230 (step S225), the data link means 220 passes the health check packet to the health check packet detection means 250 (step S226).

  When receiving the health check packet from the data link unit 220, the health check packet detection unit 250 resets the timer (step S255) and discards the health check packet (step S256).

  Even when the communication apparatus B receives a health check packet from the communication apparatus A before the timeout, the operations in steps S156 to S258 similar to the above-described steps S155 to S256 are repeated.

  Next, a case where an abnormality occurs in the transmission line 500 or the communication device A or B will be described.

  For example, here, it is assumed that the setting of the number of lines of the demultiplexer 130 is changed to a larger value than before by the number of lines setting unit 140. The demultiplexer 130 changes the set of lines used for data transmission from the network C among the lines included in the transmission path 500 according to the new number of lines.

  If the timer of the communication device A times out before receiving the non-health check packet from the network C, the health check packet generation unit 150 resets the timer and passes the health check packet to the data link unit 120 (step S157).

  When the data link unit 120 receives the health check packet from the health check packet generation unit 150 (step S129), the data link unit 120 transmits the health check packet to the transmission line 500 via the demultiplexer 130 (step S130).

  However, the multiplexer 230 determines a set of lines to be used for data reception from the network C among the lines included in the transmission path 500 according to the old number of lines. As a result of the mismatch in the number of lines, the multiplexer 230 cannot normally receive all the packets transmitted by the demultiplexer 130. As a result, it appears to the communication device B that the health check packet has been lost.

  If the timer of the communication device B times out before receiving the health check packet from the communication device A (step S259), the health check packet detection unit 250 determines the occurrence of a communication abnormality (step S260).

  Here, an example is given in which a mismatch occurs in the setting of the number of lines between the demultiplexer 130 and the multiplexer 230. However, the present embodiment is not limited to this, and may be applied when a failure occurs in the multiplexer 230 or the data link means 220 of the communication device A, the transmission path 500, or the communication device B.

  Further, the health check packet detection unit 250 may notify the transmission unit 210 of communication abnormality, whereby the transmission unit 210 may notify the network D of the link disconnection.

  Further, the health check packet detection unit 250 may notify the communication abnormality to a device or means that notifies the operation manager of the abnormality.

  The health check packet detection unit 250 may notify the line number setting unit 240 of the communication abnormality, and the line number setting unit 240 may prompt the operation manager to reset the number of lines.

  Further, the health check packet detection means 250 notifies the multiplexer 230 of the communication abnormality, whereby the multiplexer 230 selects a set of lines to be used for data reception from the network C among the lines included in the transmission path 500. You may decide again.

  As described above, the health check system according to the present embodiment enables a set of communication devices connected by a transmission path including a plurality of lines to execute the health check of the communication apparatus and the transmission path, and the high reliability related to the health check. It is possible to suppress an increase in the network load related to the health check. The reason is that when the communication device on the transmission side does not receive the non-health check packet for a certain period of time, the communication device on the transmission side transmits the health check packet, and the communication device on the reception side transmits the non-health check packet at a certain frequency or more. This is because the health check of the communication device and the transmission path is executed by receiving the check packet or the health check packet. As a result, even if the reception of non-health check packets is concentrated on the communication device on the transmission side and the communication device on the transmission side cannot transmit the health check packet, the communication device on the reception side Can perform road health checks. In addition, when the communication device on the transmission side receives the non-health check packet at a certain frequency or more, the communication device on the transmission side does not transmit the health check packet.

  The health check system according to the present embodiment can detect a mismatch in the number of lines set between the demultiplexer of the communication device on the transmission side and the multiplexer of the communication device on the reception side. The reason is that if there is a mismatch in the number of lines setting, neither the non-health check packet nor the health check packet can be received by the health check packet detection means of the communication device on the receiving side for a certain time or more.

  As described above, the insertion time which is the time from when the non-health check packet group is finally passed by the health check packet generation unit 150 to the generation of the health check packet, and the last packet reception by the health check packet detection unit 250 The detection time, which is the time from when it is determined that an abnormality has occurred, may be fixed. When these times are fixed, the packet insertion time setting unit 160 of the communication device A and the packet insertion time setting unit 160 of the communication device B can be omitted.

  Therefore, a health check system including communication devices A and B having only the components essential to the present invention is as shown in FIG.

  In order to make the insertion time or the detection time variable, the health check system of FIG. 2 includes a packet insertion time setting unit 160 added to the communication device A or a packet insertion time setting unit added to the communication device B. 160 may be added.

  In addition, this invention is not limited to the above-mentioned embodiment, It can implement in various changes and deformation | transformation in the range which does not deviate from the summary of this invention.

Claims (9)

Receiving means for receiving a frame group from the first network and extracting a first packet group including only non-health check packets;
Health check packet generation means for generating a health check packet when the non-health check packet is not received for a first time since the last reception of the non-health check packet from the first network;
First data link means for converting the first packet group and the health check packet into a transmission line frame group for a predetermined transmission line including one or more lines;
First line number setting means for setting a first line number that is the number of lines to which the transmission line frame group is distributed and transmitted among the lines of the transmission line;
Distributing the transmission line frame group to the first number of lines, and transmitting to the transmission line;
A first communication device comprising:
A multiplexer that receives the transmission path frame group from the transmission path and multiplexes a second number of lines that is the number of lines to be multiplexed;
Second line number setting means for setting the second line number;
Second data link means for extracting a second packet group from the multiplexed frame group;
When the health check packet is deleted from the second packet group from the transmission path, and the second packet group is not received for a second time since the second packet group was last received Health check packet detection means for determining that a communication abnormality has occurred;
Transmitting means for converting the second packet group into a frame group for the second network and transmitting the frame group;
A second communication device comprising:
A health check system characterized by comprising The first communication device comprises packet insertion time setting means for setting the first time;
The health check system according to claim 1, wherein the second communication apparatus includes a packet detection time setting unit that sets the second time. The health check system according to claim 1, wherein the frame group of the first network and the second network is an Ethernet frame. The health check system according to any one of claims 1 to 3, wherein the health check packet includes an ICMP (Internet Control Message Protocol) echo request notification or echo response notification. Receiving means for receiving a frame group from the first network and extracting a first packet group including only non-health check packets;
Health check packet generation means for generating a health check packet when the non-health check packet is not received for a first time since the last reception of the non-health check packet from the first network;
First data link means for converting the non-health check packet group and the health check packet into a transmission line frame group for a predetermined transmission line including one or more lines;
First line number setting means for setting a first line number that is the number of lines to which the transmission line frame group is distributed and transmitted among the lines of the transmission line;
Distributing the transmission line frame group to the first number of lines, and transmitting to the transmission line;
A communication apparatus comprising: The demultiplexer receives the transmission path frame group from the transmission path, multiplexes a second number of lines, which is the number of lines to be multiplexed, and the second number of lines. Second line number setting means for setting, second data link means for extracting a second packet group from the multiplexed frame group, and the health check packet from the second packet group from the transmission path And when the second packet group is not received for a second time since the last reception of the second packet group, health check packet detection means for determining that a communication abnormality has occurred, Transmitting the frame group for the transmission path to a second communication apparatus comprising: a transmission unit that converts the second packet group into a frame group for transmission to the second network; The communication apparatus according to claim 5. Conversion from the first packet group including only non-health check packets and the health check packet generated when the non-health check packet is not received for the first time since the last non-health check packet was received A multiplexer that receives a transmission line frame group for a predetermined transmission line including one or more lines and multiplexes a second number of lines that is the number of lines to be multiplexed;
Second line number setting means for setting the second line number;
Second data link means for extracting a second packet group from the multiplexed frame group;
When the health check packet is deleted from the second packet group from the transmission path, and the second packet group is not received for a second time since the second packet group was last received Health check packet detection means for determining that a communication abnormality has occurred;
Transmitting means for converting the second packet group into a frame group for the second network and transmitting the frame group;
A communication apparatus comprising: The multiplexer receives a frame group from the first network, extracts a first packet group including only non-health check packets, and finally receives the non-health check packet from the first network. After that, when the non-health check packet is not received for the first time, a health check packet generating means for generating a health check packet, the first packet group and the health check packet are connected to one or more lines. First data link means for converting to a transmission line frame group for a predetermined transmission line, and the number of lines to which the transmission line frame group is distributed and transmitted among lines of the transmission line. First line number setting means for setting the number of lines of 1 and distributing the transmission line frame group to the lines of the first number of lines; The communication apparatus according to claim 7, wherein the transmission path frame group is received via the transmission path from a first communication apparatus including a demultiplexer that transmits to the transmission path. Receiving a frame group from the first network, extracting the first packet group containing only non-health check packets;
A health check packet is generated when the non-health check packet is not received for a preset first time since the last non-health check packet was received from the first network;
Converting the non-health check packet group and the health check packet into a transmission line frame group for a predetermined transmission line including one or more lines;
Distributing the transmission line frame group to the first number of lines set in advance, and transmitting to the transmission line,
Receiving the transmission path frame group from the transmission path, multiplexing a second number of lines that is a preset number of lines to be multiplexed;
A second packet group is extracted from the multiplexed frame group,
The health check packet is deleted from the second packet group from the transmission path, and the second packet group has been set in advance after the second packet group is received last. If no time is received, it is determined that a communication error has occurred,
A health check method, wherein the second packet group is converted into a frame group for a second network and transmitted.

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