JP2009232263A - Communication device, and fault monitoring method - Google Patents

Abstract

A communication apparatus capable of reliably detecting a network failure while reducing the use of monitoring packets.
A communication apparatus according to the present invention is a communication apparatus that monitors a failure of a network, and receives a monitoring packet from a packet processing unit that performs transmission and reception of user packets and a monitoring target apparatus. The monitoring packet transmission / reception function for transmitting a monitoring packet when it is determined that the transmission interval of user packets to the device is longer than the specified value and the number of transmissions is not sufficient, and the frequency of packet transmission / reception with the monitoring target device And a failure monitoring unit 6 having a failure detection function for detecting a network failure based on the network.
[Selection] Figure 1

Description

  The present invention relates to a communication apparatus that performs network fault monitoring and a fault monitoring method.

  Conventionally, as a method for monitoring and detecting whether or not a failure has occurred between a packet communication device and a communication partner device, a monitoring packet is used to monitor the failure separately from a user packet used for normal transmission / reception. There is a way to do it. Specifically, the monitoring device transmits a monitoring packet to the communication partner device to be monitored, and if there is no response to the packet, it is determined that a failure has occurred with the communication partner device. To do. As a failure monitoring packet, a system using ICMP (Internet Control Message Protocol) ping or the like is generally used. A failure monitoring method as described above is disclosed in Patent Document 1 and Non-Patent Document 1.

JP-A-7-264233 The Internet Society "RFC2328 (OSPF Version 2)" 1998

  However, in the above prior art, when a failure is to be detected in a short time after occurrence, it is necessary to shorten the transmission interval of the monitoring packet. In this case, the increase in the number of monitoring packets also increases the amount of traffic in the network, causing a problem such as a delay in communication of user packets.

  Further, when the network is in a congested state, the monitoring packet may be discarded as with the user packet. In this case, since there is no response from the monitoring target device, there is a problem that there is a possibility of erroneous detection that a failure has occurred.

  The present invention has been made in view of the above, and provides a communication device and a failure monitoring method capable of reliably detecting a network failure while reducing the use of monitoring packets when performing network failure monitoring. For the purpose.

  In order to solve the above-described problems and achieve the object, a communication apparatus according to the present invention is a communication apparatus that monitors a network failure, and includes a packet processing unit that transmits and receives user packets, and a monitoring target apparatus. A monitoring packet transmission / reception function for receiving a monitoring packet and transmitting a monitoring packet when it is determined that the transmission interval of a user packet to the monitoring target device is longer than a specified value and the number of transmissions is not sufficient, and the monitoring target device Fault monitoring means having a fault detection function for detecting a fault in the network based on the frequency of packet transmission / reception with the network.

  According to the present invention, it is possible to reliably detect a network failure while reducing the use of monitoring packets.

  Embodiments of a communication apparatus and a failure monitoring method according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration example of a communication apparatus (packet communication apparatus) according to the present invention. The packet communication device includes a failure monitoring device 1 and performs network failure monitoring. The fault monitoring apparatus 1 includes a lower layer processing unit 2, a packet processing unit 3, an upper layer processing unit 4, a fault monitoring table unit 5, and a fault monitoring unit 6.

  The lower layer processing unit 2 is an interface with the network, identifies a received packet, and transfers it to each unit. The packet processing unit 3 performs processing of user packets (for example, analysis and assignment of IP headers). The upper layer processing unit 4 performs processing for upper functions such as applications. The failure monitoring table unit 5 records information necessary for failure detection such as packet transmission / reception time. The failure monitoring unit 6 includes a table monitoring unit 7 and a monitoring packet processing unit 8 and performs control related to failure monitoring. The table monitoring unit 7 periodically monitors the failure monitoring table unit 5 and requests generation of monitoring packets. The monitoring packet processing unit 8 performs processing on the received monitoring packet and processing related to generation and transmission of the monitoring packet.

  Here, an operation when a packet is received or transmitted will be described. When the lower layer processing unit 2 receives a packet from the network, the lower layer processing unit 2 determines the type of the packet, and transfers it to the packet processing unit 3 in the case of a user packet and to the failure monitoring unit 6 in the case of a monitoring packet. Each of the packet processing unit 3 and the failure monitoring unit 6 performs packet processing and updates information related to reception in the failure monitoring table unit 5.

  When transmitting a user packet, the packet processing unit 3 accesses the failure monitoring table unit 5 and determines whether or not the reception flag is significant. Then, the packet processing unit 3 and the lower layer processing unit 2 perform predetermined transmission processing and transmit the result to the network. At this time, information related to transmission in the failure monitoring table unit 5 is updated.

  In addition, the failure monitoring unit 6 periodically accesses the failure monitoring table unit 5 in parallel with the packet transmission / reception process described above, and transmits a monitoring packet from the recorded information or a failure occurs. Judgment is made whether or not.

  FIG. 2 is a diagram illustrating a configuration example of the failure monitoring table unit 5. Information to be recorded in the failure monitoring table unit 5 includes the address of the monitoring target device that is the communication partner, the latest transmission time when the packet is transmitted from the own device to the monitoring target device, and the own device is the monitoring target device. The latest reception time when receiving a packet from, and the latest reception time when a reception flag indicating that the monitoring target device has received a packet transmitted from the own device to the monitoring target device is significant, It is an item. When the packet processing unit 3 or the failure monitoring unit 6 accesses the failure monitoring table unit 5 to update information or monitor a failure, the packet processing unit 3 or the failure monitoring unit 6 searches for necessary information using the address of the monitoring target device. Note that the transmission time and reception time of the recorded packet include not only transmission / reception of user packets but also transmission / reception of monitoring packets.

  Next, the operation of the failure monitoring apparatus according to the present embodiment will be described with reference to the drawings. First, a case where a user packet is transmitted will be described. FIG. 3 is a flowchart showing the operation at the time of user packet transmission. In order to determine the reception flag of the header of the packet to be transmitted, the packet processing unit 3 searches the destination address of the monitoring target device that transmits the packet by accessing the failure monitoring table unit 5, and acquires the transmission time and the reception time. (Step S1). Next, the acquired transmission time and reception time are compared (step S2). For example, if the reception time is closer to the current time (step S2: Yes), it indicates that a packet has been received from the monitoring target device since the previous packet was transmitted to the monitoring target device. The transmission flag of the packet to be transmitted is transmitted with “1” (significant) (step S3). On the other hand, if the transmission time is closer to the current time (step S2: No), it indicates that no packet has been received from the monitored device since the previous packet was transmitted to the monitored device. Therefore, the reception flag in the header of the packet to be transmitted is transmitted with “0” (ineffective) (step S4). At this time, in any case, the information in the failure monitoring table unit 5 is updated with the current time as the packet transmission time (step S5).

  Next, a case where a user packet is received will be described. FIG. 4 is a flowchart showing an operation when receiving a user packet. When the user packet is received, the packet processing unit 3 accesses the failure monitoring table unit 5 and searches for the address of the monitoring target device that is the packet transmission source (step S11), and updates the reception time information with the current time. (Step S12). Then, it is determined whether the reception flag of the packet received from the monitoring target device is significant (step S13). For example, when the reception flag is “1” (significant) (step S13: Yes), the monitoring target device receives a packet from the failure monitoring device 1 between the previous packet transmission and the current packet transmission. The reception flag ON reception time is also updated with the current time (step S14). On the other hand, when the reception flag is “0” (ineffective) (step S13: No), the monitoring target device has received a packet from the failure monitoring device 1 between the previous packet transmission and the current packet transmission. In this case, the processing ends without updating the reception flag ON reception time.

  3 and 4, the packet processing unit 3 accesses the failure monitoring table unit 5 only in the case of packet transmission / reception with the monitoring target device. In packet transmission / reception with a device not to be monitored, the failure monitoring table unit 5 is not accessed.

  Next, a case where a monitoring packet is transmitted will be described. FIG. 5 is a flowchart showing the operation at the time of monitoring packet transmission. In parallel with the above packet transmission / reception process, the failure monitoring unit 6 periodically searches the failure monitoring table 5 with the destination address of the monitoring target device and acquires the recorded information (step S21). Then, it is determined whether the difference between the acquired transmission time of the monitoring target device and the current time is equal to or greater than a preset transmission interval (step S22). For example, if it is less than the set transmission interval (step S22: No), it is determined that the transmission of the packet is sufficiently (large) and the process is terminated. On the other hand, if it is equal to or longer than the set transmission interval (step S22: Yes), the monitoring packet is transmitted with a long packet transmission interval (less transmission) (steps S23 to S26). The monitoring packet transmission process (steps S23 to S26) is the same as steps S2 to S5 in FIG. 3 except that the process is performed by the failure monitoring unit 6.

  As for the transmission interval set in advance, the smaller the setting is, the more frequently the transmission interval is set. As a result, the frequency of transmitting monitoring packets increases.

  Next, the failure detection process will be described. FIG. 6 is a flowchart showing a process for detecting a failure. Similar to the processing at the time of monitoring packet transmission, the failure monitoring unit 6 periodically searches and records the failure monitoring table 5 with the destination address of the monitoring target device in parallel during the packet transmission / reception processing. Information is acquired (step S31). Further, it is determined whether or not the difference between the reception time of the acquired monitoring target device and the current time is equal to or longer than a preset first failure detection protection time (step S32). For example, when the first failure detection protection time is exceeded (step S32: Yes), since the reception interval of packets from the monitoring target device is open, at least between the monitoring target device and the own device 1 It is determined that a failure has occurred (step S35). On the other hand, if it is less than the first failure detection protection time (step S32: No), since the reception of the packet is sufficiently (more), the difference between the reception flag ON reception time and the current time is calculated in advance. It is determined whether it is longer than the set second failure detection protection time (≧ first failure detection protection time) (step S33). For example, if it is less than the second failure detection protection time (step S33: No), the monitoring target device has also received a packet from its own device 1, and no failure has occurred, so the processing ends. If it is equal to or longer than the second failure detection protection time (step S33: Yes), the monitoring target device has not received a packet from its own device 1 from the previous transmission to the current transmission. It is determined that a failure has occurred between the monitoring target devices (step S34).

  In addition, about the protection time set beforehand, it will become more than protection time in short time, so that it sets small. As a result, the time for determining that a failure has occurred is shortened.

  As described above, according to the present embodiment, based on the frequency of user packet transmission / reception, for example, when a large number of transmissions / receptions are performed, user packets can be transmitted / received without using monitoring packets. Network failure monitoring. As a result, it is possible to reliably detect a network failure without increasing the amount of traffic in the network.

  Further, according to the present embodiment, when the frequency of user packet transmission / reception decreases and the packet transmission / reception interval exceeds a preset value, the monitoring packet is transmitted. Thereby, the use of the monitoring packet can be reduced. Further, even when the use of monitoring packets is reduced, user packets are also used for monitoring, so that a network failure can be detected in a short time.

Embodiment 2. FIG.
In the first embodiment, the failure monitoring method by the failure monitoring apparatus has been described. In the present embodiment, fault monitoring of a network having a redundant path will be described.

  FIG. 7 is a diagram illustrating a configuration example of a network having a redundant path. In detail, a network including a packet communication device 100 including a failure monitoring device 1a that can be switched to a backup path when a failure occurs in the working path is shown.

  FIG. 8 is a diagram illustrating a configuration example of the failure monitoring apparatus 1a according to the second embodiment. The fault monitoring apparatus 1a according to the present embodiment further includes a path management unit 11 in addition to the configuration of the fault monitoring apparatus 1 according to the first embodiment. The path management unit 11 manages the working path and the backup path, and performs redundant switching when a failure occurs. In addition, about the structure similar to Embodiment 1 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  Next, the operation of the failure monitoring apparatus according to the present embodiment will be described. The basic operation is the same as in the first embodiment. In the present embodiment, two types of parameters (transmission interval and failure detection protection time) for the working path and the protection path are used for the transmission interval of the monitoring packet and the failure detection protection time. The parameter can be set to a different value for the working path and the backup path. For example, when the parameter for the protection path is set larger than that for the working path, the transmission of the monitoring packet can be reduced in the protection path, and the opportunity to determine that a failure has occurred can be reduced. For this reason, when determining the failure detection, the failure monitoring unit 6 determines whether to use the parameter for the working path or the protection path by using information from the path management unit 11.

  As described above, according to this embodiment, two types of parameters are used for the working path and the protection path. For example, by setting a large value for the parameter for the protection path, On the other hand, the transmission of monitoring packets is reduced, and the opportunity to determine that a failure has occurred is reduced. As a result, failure monitoring can be performed without increasing the amount of traffic in the network.

Embodiment 3 FIG.
In the failure monitoring method in the first and second embodiments, the failure is detected with the same parameters (transmission interval, failure detection protection time) for all monitoring target devices. In the present embodiment, a method of adding a traffic amount with the monitoring target device as a failure determination factor and using different parameters depending on the monitoring target device will be described. Here, processing different from those in the first and second embodiments will be described.

  FIG. 9 is a diagram illustrating a configuration example of the failure monitoring apparatus 1b according to the third embodiment. The fault monitoring device 1b according to the present embodiment further includes a traffic measuring unit 21 in addition to the configuration of the first embodiment. The traffic measurement unit 21 measures the traffic amount of user packets. Further, the failure monitoring table unit 5 is replaced with a failure monitoring table unit 5b. In addition, about the structure similar to Embodiment 1 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  FIG. 10 is a diagram illustrating a configuration example of the failure monitoring table unit 5b. In the present embodiment, items of user packet transmission traffic amount and user packet reception track amount are added to the failure monitoring table unit 5 (see FIG. 2) of the first embodiment. Note that description of the same items as those in the first embodiment is omitted.

  Next, the operation of the failure monitoring apparatus according to the present embodiment will be described. The basic processing is the same as in the first embodiment. In the present embodiment, the traffic measurement unit 21 accesses the failure monitoring table unit 5b and records and updates the measured traffic amount in the items of user packet transmission traffic amount and user packet reception traffic amount.

  Here, it is considered that the monitoring target device with a small amount of traffic for user packet transmission / reception is less affected by the failure due to the occurrence of the failure even when the failure detection time is longer than the monitoring target device with a large traffic amount. In other words, the failure monitoring unit 6 can reduce the transmission of monitoring packets to the monitoring target device with a small traffic volume by changing the set value of the failure detection parameter according to the transmission / reception traffic volume of the user packet. Moreover, the opportunity to judge that a failure has occurred can be reduced.

  As a method of changing the parameter setting value, for example, a method may be considered in which several threshold values are provided for the traffic volume, and the reference parameter is doubled, quadrupled, etc. depending on the interval.

  As described above, according to the present embodiment, the setting value of the parameter is changed according to the traffic amount of the user packet, for example, the transmission interval or the failure detection protection time of the monitoring target device with a small traffic amount is increased. By setting it, the transmission of monitoring packets is reduced, and the opportunity to determine that a failure has occurred is reduced. As a result, failure monitoring can be performed without increasing the amount of traffic in the network.

  In the present embodiment, the parameter setting is changed according to the traffic amount of the user packet. However, the present invention is not limited to this, and a specific parameter can be set for a specific traffic amount. . In the above description, the parameters are simply changed based on the traffic amount of the user packet. However, the parameters can be changed based on the number of sessions, the number of flows, and the like.

Embodiment 4 FIG.
In the second embodiment, the failure monitoring of a network having a redundant configuration has been described. In the present embodiment, a description will be given of failure monitoring of a network in which routes are partially overlapped. Here, processing different from those of the first to third embodiments will be described.

  FIG. 11 is a diagram illustrating a configuration example of a network in which routes are partially overlapped. In FIG. 11, there are four packet communication devices (100a to 100d) equipped with a failure monitoring device, and the route between the packet communication device 100a and the other packet communication devices (100b, 100c, 100d) partially overlaps. ing.

  FIG. 12 is a diagram illustrating a configuration example of the failure monitoring apparatus 1c according to the fourth embodiment. The failure monitoring apparatus 1c of the present embodiment further includes a path management unit 31 and a path management table unit 32 in addition to the configuration of the first embodiment. The path management unit 31 manages the route to the monitoring target device. The path management table unit 32 holds path information. In addition, about the structure similar to Embodiment 1 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  Next, the operation of the failure monitoring apparatus according to the present embodiment will be described. As shown in FIG. 11, a part of the route between each monitoring target device and the device itself may overlap. In such a case, the occurrence of a failure in the overlapping section can be detected by monitoring the failure of another route. Therefore, the traffic amount of the monitoring packet is reduced by the following method.

  For example, when the packet communication device 100a monitors a failure of another device, the packet communication device 100a monitors the packet communication device 100b with normal parameters (transmission interval, failure detection protection time). On the other hand, regarding the monitoring of the packet communication devices 100c and 100d, the path management unit 31 recognizes that there is a section overlapping with the route to the packet communication device 100b by checking the information in the path management table unit 32. Therefore, the packet communication device 100a sets a parameter having a larger value than the failure monitoring for the packet communication device 100b. In addition, as the number of overlapping sections increases, the value set for the parameter is increased. In the present embodiment, it can be recognized by the processing of the path management unit 31 that the packet communication device 100c has more overlapping sections than the packet communication device 100d. Therefore, the parameter setting value for monitoring the packet communication device 100c Is made larger than that of the packet communication device 100d.

  Here, when a failure is detected between the packet communication device 100a and the packet communication device 100b, the failure is similarly detected between the packet communication device 100c or between the packet communication device 100c and the packet communication device 100d. There is a possibility. In this case, in order to determine whether or not there is a failure in the overlapping section, in the packet communication device 100c and the packet communication device 100d, the failure monitoring unit 6 can transmit and communicate a monitoring packet without waiting for the set transmission interval. Check if it is in a state. It is assumed that a method for obtaining a communication path uses a general function such as “Trace route”.

  As described above, according to the present embodiment, when monitoring a monitoring target device with overlapping routes, a monitoring packet can be further increased by setting a transmission interval and a failure detection protection time set as parameters to be large. We decided to reduce the number of transmissions and reduce the chance of judging that a failure occurred. As a result, failure monitoring can be performed without increasing the amount of traffic in the network.

  In addition, according to the present embodiment, it is possible to use the result of failure detection in each device in a composite manner by considering the overlap of the route between each device to be monitored. By identifying whether there is a failure, it is possible to narrow down the section where the failure occurred.

Embodiment 5 FIG.
In the first to fourth embodiments, a case where a packet cannot be transmitted / received to / from the monitoring target device is detected as a failure. However, depending on the application, if the packet transmission / reception delay time increases due to congestion or the like, communication may not be established. In the present embodiment, considering the delay time of packet transmission / reception, a case where the delay time is equal to or greater than a preset threshold is detected as a failure.

  FIG. 13 is a diagram illustrating a configuration example of the failure monitoring apparatus 1d according to the fifth embodiment. The fault monitoring device 1d of the present embodiment further includes a time synchronization unit 41 in addition to the configuration of the first embodiment. The time synchronizer 41 has a function of synchronizing the internal time with the reference time. Further, the failure monitoring table unit 5 is replaced with a failure monitoring table unit 5d. In addition, about the structure similar to Embodiment 1 mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  FIG. 14 is a diagram illustrating a configuration example of the failure management table unit 5d. Here, an item of delay state is added to the failure monitoring table unit 5 (see FIG. 2) of the first embodiment. Note that description of the same items as those in the first embodiment is omitted.

  Next, the operation of the failure monitoring apparatus according to the present embodiment will be described. FIG. 15 is a flowchart showing an operation of detecting a failure due to delay. Since other operations are the same as those in the first to fourth embodiments, description thereof is omitted.

  For example, when the failure monitoring device 1d receives a packet, the packet processing unit 3 or the failure monitoring unit 6 checks the value of the delay state flag of the packet (step S41). For example, when the delay state flag is “1” (large delay) (step S41: No), it is determined that a failure has occurred between the own device and the monitoring target device (step S42). On the other hand, when the delay state flag is “0” (small delay) (step S41: Yes), or after executing the processing of step S42, the packet processing unit 3 or the failure monitoring unit 6 further determines the current time and the packet header. The delay time is calculated from the difference from the transmission time at (step S43), and it is determined whether or not a preset threshold value is exceeded (step S44). For example, if the preset threshold value is exceeded (step S44: Yes), “1” (large delay) is recorded in the delay state of the failure monitoring table unit 5d (step S45), and the monitoring target It is determined that a failure has occurred between the device and the device itself (step S47). On the other hand, when the set threshold value is not exceeded (step S44: No), “0” (small delay) is recorded in the delay state of the failure monitoring table unit 5d (step S46).

  When transmitting a packet, the packet processing unit 3 or the failure monitoring unit 6 accesses the failure management table unit 5d, searches for the monitoring destination address (in this case, the transmission destination address of the packet), and records it. Is written in the header of the packet to be transmitted as a delay state flag. In addition, the current time is also written in the header as the packet transmission time. Since the time to be written in the header of the packet is consistent with the monitoring target device by the time synchronization unit 41, when the monitoring target device receives the packet, the difference from the current time is accurately calculated. Can do.

  As described above, according to the present embodiment, in the packet transmission / reception between the monitoring target apparatus and the own apparatus, when a delay equal to or greater than a preset threshold occurs, it can be detected as a failure. As a result, failure monitoring by user packets based on packet transmission / reception delay time becomes possible.

  Further, according to the present embodiment, since the delay can be detected as a failure, even if the application does not establish communication when the delay time is increased, the failure monitoring by the user packet can be performed.

Embodiment 6 FIG.
In the first to fourth embodiments, since the occurrence of a failure is determined based on the presence or absence of packet communication, there is no difference in determination between the failure monitoring device (self device) and the monitoring target device. However, in the fifth embodiment, the failure monitoring apparatus that has received a packet calculates a delay time, and determines the occurrence of a failure by comparing the calculation result with a preset threshold value. In the present embodiment, a method will be described in which the failure monitoring apparatus that has transmitted a packet determines whether or not the delay time of the transmitted packet is a failure.

  FIG. 16 is a diagram illustrating a configuration example of the failure monitoring table unit. In the fifth embodiment, an item of delay state is added. However, this item is deleted, and in this embodiment, an item of statistical information regarding delay is added instead. Note that description of the same items as those in the first embodiment is omitted.

  Next, the operation of the failure monitoring apparatus according to the present embodiment will be described. In the present embodiment, the monitoring target device that has received the packet from the failure monitoring device (packet transmission source) calculates the delay time (the calculation method is the same as in the fifth embodiment). No comparison is made between the delay time and the threshold value (no occurrence of failure is determined). Thereafter, the monitoring target device monitors the failure of the packet in which the statistical information of at least one of the average value, variation, maximum value, and minimum value of the delay time and the delay time calculated by the own device are written in the header. Send (reply) to the device. Then, the failure monitoring device of the packet transmission source determines whether or not this delay is at the failure level based on the statistical information written in the header and the delay time. As a determination method, for example, a method is conceivable in which a value obtained by multiplying a maximum value or average value of statistical information by a predetermined coefficient is used as a threshold value for comparing with a delay time. For example, when the failure monitoring device determines that the delay time calculated by the monitoring target device is not a failure, the failure monitoring device does not need to perform processing corresponding to the failure and has an opportunity to use the monitoring packet. Will be reduced.

  As described above, according to the present embodiment, when a delay occurs in packet transmission from the failure monitoring apparatus to the monitoring target apparatus, the failure monitoring apparatus can determine the occurrence of the failure. As a result, failure monitoring by user packets based on packet transmission / reception delay time becomes possible. Further, according to the present embodiment, since the delay can be detected as a failure, even if the application does not establish communication when the delay time is increased, the failure monitoring by the user packet can be performed.

  As described above, the communication device according to the present invention is useful when performing network failure monitoring, and is particularly suitable for a communication device that performs failure monitoring without increasing traffic in the network.

It is a figure which shows the structural example of the communication apparatus concerning this invention. It is a figure which shows the structural example of the table part for trouble monitoring. It is a flowchart which shows the operation | movement at the time of user packet transmission. It is a flowchart which shows the operation | movement at the time of user packet reception. It is a flowchart which shows the operation | movement at the time of monitoring packet transmission. It is a flowchart which shows the process which detects a failure. It is a figure which shows the structural example of the network with a path | route of a redundant structure. It is a figure which shows the structural example of the failure monitoring apparatus of Embodiment 2. FIG. 6 is a diagram illustrating a configuration example of a failure monitoring apparatus according to Embodiment 3. FIG. It is a figure which shows the structural example of the table part for trouble monitoring. It is a figure which shows the structural example of the network with which the path | route partially overlapped. It is a figure which shows the structural example of the failure monitoring apparatus of Embodiment 4. FIG. FIG. 10 is a diagram illustrating a configuration example of a failure monitoring apparatus according to a fifth embodiment. It is a figure which shows the structural example of the table part for fault management. It is a flowchart which shows the operation | movement which detects the failure by delay. It is a figure which shows the structural example of the table part for trouble monitoring.

Explanation of symbols

1, 1a, 1b, 1c, 1d Fault monitoring device 2 Lower layer processing section 3 Packet processing section 4 Upper layer means section 5, 5b, 5d Fault monitoring table section 6 Fault monitoring section 7 Table monitoring 8 Monitoring packet processing section 11 Path management unit 21 Traffic measurement unit 31 Path management unit 32 Path management table unit 41 Time synchronization unit 100, 100a, 100b, 100c, 100d Packet communication device

Claims (8)

A communication device for monitoring a network failure,
Packet processing means for transmitting and receiving user packets;
A monitoring packet transmission / reception function for receiving a monitoring packet from the monitoring target device and transmitting the monitoring packet when it is determined that the transmission interval of the user packet to the monitoring target device is longer than a specified value and the number of transmissions is not sufficient; And a fault monitoring means having a fault detection function for detecting a fault in the network based on the frequency of packet transmission / reception with the monitoring target device,
A communication apparatus comprising: The fault monitoring means includes
A parameter indicating the frequency of packet transmission / reception with the monitoring target device is defined as a packet reception interval, and it is determined that a failure has occurred in the network when the reception interval is longer than a specific protection time. The communication device according to claim 1. Path management means for managing the working communication path and the backup communication path with the monitoring target device and switching the communication path when a failure occurs;
Further comprising
The path management means uses the specified value of the transmission interval and the specific protection time individually for detecting a failure in the working communication path and the backup communication path, and a specified value of the transmission interval for detecting the standby communication path fault and 3. The communication apparatus according to claim 2, wherein the value of the specific protection time is set to be larger than the value for detecting the working path failure. Traffic measurement means for measuring the amount of traffic of user packets;
Further comprising
The communication apparatus according to claim 2 or 3, wherein the traffic measurement unit sets the specified value of the transmission interval and the value of the specific protection time to be larger as the traffic amount is smaller.   When a part of communication paths between a plurality of monitoring target devices overlaps, the fault monitoring means determines the current transmission interval specified value and the specific monitoring target device among the plurality of monitoring target devices. The processing based on the value of the protection time is performed, and with respect to the remaining monitoring target devices, the processing is performed by setting the prescribed value of the transmission interval and the value of the specific protection time larger. 4. The communication device according to 4.   The failure monitoring means further obtains a delay time required for transmission / reception of a packet with the monitoring target device, and when the delay time exceeds a threshold value, a communication path between the monitoring target device and the own device The communication apparatus according to claim 2, wherein a failure is determined to occur.   The failure monitoring means further includes at least one of a delay time for transmission / reception of a packet calculated by the monitoring target device, and an average value, variation, maximum value, and minimum value of the delay time based on the statistics of the delay time. Packet including the information is received from the monitoring target device, and based on the delay time and the statistical information included in the received packet, the occurrence of a failure in the communication path between the monitoring target device and the own device is determined. The communication apparatus according to any one of claims 2 to 5, wherein A packet transmission / reception step for transmitting / receiving a user packet; and
A process of receiving a monitoring packet from the monitoring target apparatus, and a process of transmitting the monitoring packet when it is determined that the transmission interval of the user packet to the monitoring target apparatus is longer than the specified value and the number of transmissions is not sufficient. Monitoring packet transmission and reception step;
A failure detection step of detecting a network failure based on the frequency of packet transmission / reception with the monitoring target device;
A failure monitoring method comprising:

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