JP2014192869A - Failure localization device, transmission network system, failure localization method, and its program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a failure localization device, a transmission network system, a failure localization method, and its program, capable of identifying a failure generation section with accuracy independently of a length of a failure detection time of each node, in a network system including a plurality of nodes.SOLUTION: A failure localization device is installed in each node, and detects failures generated in a section between the node and an upstream node on the basis of information acquired by communications with adjacent upstream and downstream nodes, in a transmission network system in which a plurality of nodes communicate with each other via a control plane. The failure localization device comprises: a waiting time setting part calculating a waiting time t by subtracting a failure detection time of the downstream node from that of the own node and setting it when the failure detection time of the own node is longer than that of the downstream node; and a failures generation detector, on receipt of such a notification from the downstream node that failures are detected, waiting a lapse of the waiting time t, and then, detecting presence or absence of generation of failures at the upstream side.

Description

  The present invention relates to a transmission apparatus such as a router and an optical cross-connect and a network system formed by combining these, and in particular, a failure localization apparatus, a transmission network system, a failure localization method for detecting a failure such as a signal interruption, and the like Regarding the program.

  In recent years, networks have been constructed by combining routers, optical cross-connect devices, or TDM (Time Division Multiplexing) devices. Conventionally, this network has been centrally controlled by the management plane. However, in recent years, a control plane responsible for operations such as route control has been added, and this has led to path setup / release and failure recovery. .

In addition, GMPLS (Generalized) is a technology that applies the concept of traffic engineering technology to the TDM, wavelength path, and fiber layers and can control IP networks and optical networks integratedly and seamlessly using a single control plane. Multi-Protocol Label Switch) is known.
The GMPLS protocol group includes LMP (RFC 4204), which manages fault sections in the network.

  Here, a transmission network system including a plurality of nodes (node 101, node 102, node 103, and node 104) that are devices such as routers and optical cross-connect devices will be described with reference to FIG. It is assumed that the nodes can communicate with each other by LMP through a control plane (not shown).

  FIG. 9 shows a case where a failure (optical signal interruption) occurs between the node 101 and the node 102 in a situation where a signal as user traffic flows in a direction from the node 101 to the node 104. Yes. That is, it is assumed that there is a failure only between the node 101 and the node 102, and there is no failure between the node 102 and the node 103 and between the node 103 and the node 104.

  Furthermore, the time required for the node 101 to detect a failure (failure detection time) is 100 ms (milliseconds) as shown in FIG. 9, and similarly, the failure detection time at the nodes 102, 103, and 104 is as follows. Are 200 ms, 300 ms, and 400 ms, respectively.

  In LMP in such a transmission network system, a downstream node that detects a failure notifies the upstream node of the failure state of the node (whether or not a failure has occurred on its own upstream side), and from the upstream node corresponding thereto. It is determined whether or not there is a failure on the local node side based on the response content. That is, the downstream node that detects the failure determines that there is no failure on the own node side (between the upstream node and the own node) when there is also a failure on the upstream side of the upstream node. When there is no failure on the side, it is determined that there is a failure on the own node side.

  Here, each node in the case shown in FIG. 9 has a failure detection time as described above, and can detect a failure at an earlier stage than a downstream node. Since the detection result can be responded to, the fault occurrence section can be correctly specified as the entire system.

The specific operation of failure detection by each node is as follows with reference to FIG.
First, the node 102 that has detected the failure notifies the node 101 of an SF notification with a CS message, and the node 101 returns an Ack (acknowledgment response) to the message.
Next, the node 101 checks whether or not a failure has occurred on its upstream side, and here, since there is no failure, it is OK with a CS (Channel Status) message. ).
Subsequently, since the node 102 has returned OK, it can be determined that a failure has occurred on the upstream side of the node 102 and that no failure has occurred on the upstream side of the node 101. Determine that there is a failure.

  The same sequence as described above also runs between the node 102 and the node 103, and between the node 103 and the node 104. As a result, each of the node 103 and the node 104, which are downstream nodes, is connected between the node 102 and the node 103, and between the node 103 and the node 103. It is determined that there is no failure between 104.

  That is, the failure occurrence section is specified between the node 101 and the node 102 based on each determination result.

  As a technique related to the above-described content, for example, the following technical content (Patent Document 1 or 2) is known.

  In Patent Document 1, when a failure occurs in the lower network, a predetermined hold time is provided before the router performs topology information update and detour route setting, thereby reducing the number of times of the update and setting. The technical content of reducing the processing load in a router or the like is disclosed.

  Further, Patent Document 2 discloses a transmission network system in which a plurality of transmission apparatuses having a function of detecting whether or not a failure has occurred upstream communicate with each other by LMP through a control plane. Here, the failure detection time of the transmission device that takes the longest time to detect the failure is set as a delay time (a time during which each transmission device can reliably detect the failure), and a failure is detected from the downstream transmission device. The technical content is disclosed that the transmission device that has received the notification returns a response to the notification after the delay time has elapsed.

JP 2003-258907 A JP 2007-329867 A

  However, as in the related art, the determination method depending on one function of the LMP that finds the fault section cannot find the fault section accurately.

That is, as described based on FIG. 9 above, the failure occurrence section should be specified between the node 101 and the node 102 by the LMP Fault Localization, but the failure detection protection time is set for each node. If it is set, the failure detection time required for each will be different, resulting in inconvenience that accurate determination cannot be performed at the downstream node.
Similarly, in a multi-vendor environment in which devices of a plurality of manufacturers exist as each of the above nodes, failure detection times vary (unevenness), and there is a problem that a failure section cannot be found accurately.

  For example, as shown in FIG. 10, when the node 204 is 200 ms and the node 203 positioned upstream thereof is 400 ms, as shown in FIG. 10, for example, the failure detection time of the upstream node is a downstream node. This occurs when the failure detection time is long. Also in the transmission network system shown here, there is a failure (optical signal interruption) only between the node 201 and the node 202, and there is no failure between the node 202 and the node 203 and between the node 203 and the node 204, as in FIG. Assume a case.

Specifically, the above-described inconvenience occurs due to each node performing the following operation (FIG. 10).
First, the node 204 that has detected a failure notifies the node 203 of an SF notification using a CS message, and the node 203 returns an Ack (acknowledgment response) to the message.

If the failure detection times of the node 203 and the node 204 are the same, or if the node 204 takes longer to detect the failure than the node 203, when the node 204 receives a notification that the failure has been detected. Since the node 203 detects a failure on the upstream side, SF (notice of failure) is notified by the CS message.
However, in the situation shown in FIG. 10, the node 203 has not yet detected the failure on the upstream side when the notification indicating that the failure has been detected is received from the node 204. OK (notifying that there is no failure) is notified by the CS message. Therefore, the node 204 that has received the notification makes an erroneous determination that there is a failure between the node 203 and the node 204 that is a normal section.

Also between the node 202 and the node 203, when the node 203 detects a failure, a sequence similar to the above is performed with the node 202. Here, the failure detection time of the upstream node 202 is shorter than that of the node 203. Therefore, since the Fault Localization is correctly executed, the node 203 that has received the notification that there is a failure from the node 202 accurately determines that there is no failure between the node 202 and the node 203.
Since no failure has occurred between the node 201 and the node 202, the node 202 that has received the notification that there is no failure from the node 201 that has not detected the failure is the node 201-node 202. Accurately determine that there is a failure in between.

  Here, GMPLS has a failure recovery function for switching a link or a path when a failure is found. For this reason, as described above, if it is erroneously determined that the section is a faulty section even though it is a normal section, the fault recovery function passes the normal section or the section. A path becomes a switching target, and this causes a problem that a section and a path that do not need to be switched are switched.

  In addition, the predetermined hold time described in Patent Document 1 is set in order to delay the update or the like by the router, that is, erroneous detection of a failure between nodes based on the failure detection time by each node. There is no disclosure of the technical content of setting a waiting time for prevention.

  Furthermore, in the transmission network system described in Patent Document 2, regardless of the magnitude of the failure detection time in each transmission device, the above delay time is uniformly assigned to each transmission device as a waiting time from downstream reception to response reply. Since the setting is performed, the transmission apparatus capable of detecting a failure without the setting has an inconvenience that an unnecessary waiting time increases. Further, even in a transmission apparatus that requires the above setting, there is an inconvenience that an unnecessary waiting time increases due to an excessive setting time.

(Object of invention)
The present invention is intended to improve the disadvantages of the above-described conventional example, and in particular, in a network system including a plurality of nodes, the fault occurrence section can be accurately determined regardless of the length of the fault detection time of each node. It is an object of the present invention to provide a specified failure localization apparatus, a transmission network system, a failure localization method, and a program thereof.

  In order to achieve the above object, in the fault localization apparatus according to the present invention, the communication with the adjacent upstream and downstream nodes provided in each node in a transmission network system in which a plurality of nodes communicate with each other. Is a fault localization device that detects a fault that has occurred in the section with the upstream node based on the information obtained by the above-mentioned, and when the fault detection time of the own node is longer than the fault detection time of the downstream node, Subtract the failure detection time of the downstream node from the failure detection time of the own node, and set a waiting time setting unit that sets this calculation time as the waiting time of the own node, and a notification that a failure has been detected from the downstream node And a failure occurrence detecting unit that detects whether or not a failure has occurred on the upstream side after the waiting time has elapsed.

The transmission network system according to the present invention is a transmission network system including a plurality of nodes that communicate with each other through a control plane,
Each of the nodes has a configuration that includes a failure localization device that detects a failure that occurs in a section with the upstream node based on information obtained by the communication with the adjacent upstream and downstream nodes. .

  Furthermore, in the failure localization method according to the present invention, the information obtained by the communication with the adjacent upstream and downstream nodes in the transmission network system in which a plurality of nodes communicate with each other. In the failure localizing apparatus for detecting a failure occurring in the section with the upstream node, the failure detection time of the downstream node is obtained, and the failure detection time of the own node is more than the obtained time. When it is long, when the acquired time is subtracted from the failure detection time of the own node, the calculation time is set as the waiting time of the own node, and a notification that a failure has been detected is received from the downstream node In addition, after the waiting time has elapsed, the presence or absence of a failure on the upstream side is detected.

  In the fault localization program according to the present invention, the information obtained by the communication with the adjacent upstream and downstream nodes in the transmission network system in which a plurality of nodes communicate with each other, In the failure localizing apparatus for detecting a failure occurring in the section with the upstream node, the failure detection of the own node is detected when the failure detection time of the own node is longer than the failure detection time of the downstream node. Subtracting the failure detection time of the downstream node from the time, and waiting time setting means for setting the calculated time as the waiting time of the own node, when receiving a notification that a failure has been detected from the downstream node, A computer provided in advance in the failure localization device as failure occurrence detection means for detecting the occurrence of failure on the upstream side after waiting time has elapsed Characterized in that to ability.

  According to the present invention, in a network system including a plurality of nodes, in particular, a failure detection time is notified in advance between the nodes, and a waiting time t until failure detection is determined is calculated and set using this data. Therefore, the failure localization apparatus, the transmission network system, the failure localization method, and the program thereof can accurately identify the failure occurrence section regardless of the length of the failure detection time of each node. Provision is possible.

It is a sequence diagram which shows the node structure and operation | movement of the transmission network system concerning embodiment of this invention. It is a block diagram which shows the whole structure of the transmission network system disclosed in FIG. FIG. 3 is a diagram illustrating a flow of establishing a control channel when each node in the transmission network system disclosed in FIG. 2 starts communication with an adjacent node. FIG. 3 is a diagram illustrating a situation in which C-Type for notifying a failure detection time is added to a CONFIG object in the transmission network system disclosed in FIG. 2. It is a figure which shows a mode that 30 (C-Type = 30) was defined as Fault Detection in the situation disclosed in FIG. FIG. 3 is a block diagram illustrating a functional configuration of a failure localizing apparatus that detects a failure that is included in each node of the transmission network system disclosed in FIG. 2 and that occurs in a section with an adjacent upstream node. 7 is a flowchart showing an operation when the failure localization apparatus disclosed in FIG. 6 obtains a waiting time t. It is a flowchart which shows the operation | movement concerning the fault detection which the fault localization apparatus disclosed in FIG. 6 performs. In the transmission network system concerning a related technique, it is a sequence diagram which shows the case where the failure detection time of each node does not affect the detection accuracy of a failure. In the transmission network system concerning a related technique, it is a sequence diagram which shows the case where the misjudgment concerning a failure occurrence is performed due to the failure detection time being different for each node.

Embodiment
Embodiments of a fault localization apparatus and a transmission network system according to the present invention will be described with reference to FIGS.

(Overall configuration)
As shown in FIG. 2, the transmission network system 30 includes a plurality of nodes (node 11, node 12, node 13, and node 14) that are devices such as routers and optical cross-connect devices. Communication is performed by LMP through the control plane 20.

Further, the LMP is configured to establish a control channel when each of the nodes starts communication with an adjacent node.
Therefore, first, a configuration for establishing a control channel will be described based on FIG. 3 in which the nodes 13 and 14 in FIG. 2 are extracted and shown. Note that FIG. 4 and FIG. 5 are referred to as appropriate.

By using HelloConfig (C-Type = 1) of the CONFIG object (Class = 6) shown in FIG. 4, each node notifies each other of the transmission interval of the Hello packet and the Hello packet reception timeout time, It is configured to determine a value of a waiting time t for determining whether or not a failure will be described later.
C-Type is newly added to the CONFIG object to notify the failure detection time.

  Here, 20 to 127 (C-Type = 20 to 127) is Private Use. For this reason, any of these can be defined as a fault detection. In this embodiment, as shown in FIG. 5, 30 (C-Type = 30) is defined as a fault detection. It was.

  Further, at the time of establishing the control channel shown in FIG. 3, each node adopts a configuration in which the fault detection time of the adjacent node is obtained by exchanging this object with the adjacent node.

  Since both the node 13 and the node 14 support the contents of this object, as shown in FIG. 3, the node 14 responds to the configuration notification (Config) from the node 13 with a Config Ack message, The node 13 is configured to respond with a Config Ack message to the setting notification (Config) from 14. Note that a node that cannot receive a notification from an adjacent node because the content of the object is not supported is configured to respond with a Config Nack message.

  The control channel is established in the same manner as described above between the other nodes shown in FIG. 2 (between node 11 and node 12, and between node 12 and node 13). A description of a specific protocol for establishing a control channel is provided in RFC (Request For Comments), and is omitted here.

  Next, a configuration related to the Fault Localization process of FIG. 2 will be described with reference to FIG. FIG. 1 shows each node (nodes 11 to 14) included in the above-described transmission network system 30 (FIG. 2).

  FIG. 1 and FIG. 2 show a case where a failure (optical signal interruption) occurs between the node 11 and the node 12 in a situation where a signal that is user traffic flows in a direction from the node 11 to the node 14. Yes.

Therefore, the description here is made in the direction of the signal from the node 11 to the node 14, and in such a case, the node 14 is the node located at the most downstream side. Further, it is assumed that there is a failure only between the node 11 and the node 12, and there is no failure between the node 12 and the node 13 and between the node 13 and the node 14.
In the sequence of FIG. 1, the LMP messages other than the CS message are not directly related to the Fault Localization and are not directly related to the present invention, and thus the description thereof is omitted.

  Each node that has established the control channel as described above and obtained the failure detection time of the adjacent downstream node compares this with the failure detection time of its own node, so that the failure detection time of its own node It is comprised so that it may determine whether it is long.

  At that time, after receiving a CS message from a downstream node, which will be described later, the node that has determined that its own node is longer has a waiting time t that is a waiting time for determining whether or not a failure has occurred. It is calculated and set by a subtraction formula of “failure detection time−downstream node failure detection time”, and is used when detecting whether or not a failure has occurred on the upstream side.

  In other words, the waiting time t (until the failure detection is confirmed) for determining whether or not a failure has occurred is generated when the failure detection time of the upstream node is longer than the failure detection time of the downstream node. In order to avoid the “inconvenience that the upstream node responds with the detection result”, the upstream node calculates and sets in advance.

  As shown in FIG. 1, the failure detection time of each node in the present embodiment is 100 milliseconds for the node 11, 300 milliseconds for the node 12, 400 milliseconds for the node 13, and 200 milliseconds for the node 14.

  Therefore, between node 11 and node 12, and between node 12 and node 13, the failure detection time of the upstream node in each section is shorter than that of the downstream node, so it is necessary to provide a waiting time t when detecting the failure on the upstream side. However, the node 11 and the node 12 are configured to detect a failure on the upstream side as usual.

  On the other hand, since the failure detection time of the upstream node 13 is longer between the node 13 and the node 14, the node 13 subtracts the failure detection time of the downstream node 14 from the failure detection time of the own node. The waiting time t is obtained, and the presence or absence of the occurrence of a failure on the upstream side is detected after the waiting time t has elapsed.

Specifically, the following configuration is adopted.
First, the node 14 detects a failure occurring upstream, and notifies the node 13 of an SF notification with a CS message (CS (SF, D = 0)), and the node 13 that has received this notification An Ack (CS Ack) is sent back to notify the node 14 that the message has been received.

  Next, after waiting for elapse of t seconds, which is a preset waiting time, the node 13 detects (checks) whether or not a failure has occurred on its upstream side. SF, D = 1)) is configured to send a message to the node 14.

  In response to this, the node 14 returns Ack (CS Ack) to transmit to the node 13 that the message has been received, and accurately determines that there is no failure between the node 13 and the node 14. The structure is adopted.

The same applies between the node 11 and the node 12.
The node 12 that has detected the failure notifies the node 11 of the fact of the detection by a CS message with a CS message (CS (SF, D = 0)), and the node 11 that has received this sends an Ack (CS Ack) to the message. In addition to replying, it is configured to detect (check) the presence or absence of a failure on the upstream side of itself.

  In this section, since the failure detection time of the upstream node 11 is shorter than the failure detection time of the downstream node 12, the node 11 needs a waiting time t until the failure detection is confirmed when performing the above detection. Therefore, the configuration is such that a failure on the upstream side is detected as usual. In this node configuration, the node 11 is configured not to calculate and set the waiting time t, as will be described later.

  Here, since no failure has occurred on the upstream side of the node 11, the node 11 transmits a (CS (OK, D = 1)) message indicating that no failure has occurred to the node 12. The node 12 that has returned Ack (CS Ack) determines that there is a failure between the node 11 and the node 12.

Further, the same applies between the node 12 and the node 13.
The node 13 that has detected the failure notifies the node 12 of an SF notification with a CS message (CS (SF, D = 0)), and the node 12 that receives the notification sends an Ack (CS Ack) to the message. In addition to replying, it is configured to detect (check) the presence or absence of a failure on the upstream side of itself.

  Also in this section, since the failure detection time of the upstream node 12 is shorter than the failure detection time of the downstream node 13, when performing the above detection, the node 12 sets the waiting time t until failure detection is confirmed. Since it is not necessary, the upstream side failure is detected as usual. As described above, the node 12 is configured not to calculate and set the waiting time t.

  Here, since a failure has occurred on the upstream side of the node 12, the node 12 transmits a (CS (SF, D = 1)) message to the effect that a failure has occurred to the node 13, and responds to this message. The node 13 that has returned Ack (CS Ack) determines that there is no failure between the node 12 and the node 13.

  As described above, in this embodiment, each node performs fault localization, and the upstream node that has received the CS message from the downstream node does not immediately respond to the failure state at that time with the CS message. Since the configuration in which the failure state of the own node is detected after waiting for the preset waiting time t and the detection result is appropriately notified to the downstream node and the upstream node by a CS message is adopted, , A failure occurring between the node 11 and the node 12 can be accurately identified.

That is, each node can respond to the correct failure state with a CS message by adding a waiting time t until the failure detection is confirmed before receiving a CS message from a downstream node. Localization works correctly, and it becomes possible to correctly determine the failure section in the entire system.
In addition, since the setting of the waiting time t is automatically performed by each node when the control channel is established, there is an advantage that the user or the like does not need to be set from the outside.

(Configuration that each node contains)
Next, a functional configuration of a failure localization apparatus that detects a failure that is included in each of the above-described nodes and occurs in a section with an adjacent upstream node will be described with reference to FIG.

Here, the nodes 12, 13 and 14 shown in FIG. 1 and FIG. 2 are designated as the upstream node 12, the own node 13, and the downstream node 14 as shown in FIG. Each figure is made to correspond by setting the configuration to the node configuration 10.
Accordingly, the upstream node 12, the own node 13, and the downstream node 14 that are adjacent nodes are configured to communicate with each other through the control plane 20.

  That is, in the transmission network system in which the upstream node 12, the local node 13, and the downstream node 14 which are a plurality of nodes communicate with each other through the control plane 20, the fault localization device 43 equipped in the local node 13 Thus, it is configured to detect a failure occurring in the section with the upstream node 12 based on information obtained by communication with the upstream and downstream nodes 12 and 14.

The configuration contents of the failure localizing device 42 and the failure localizing device 44 equipped in the upstream node 12 and the downstream node 14 are the same as the configuration content of the failure localizing device 43 shown below. In addition, the node 11 shown in FIG. 1 and FIG. 2 has the same configuration as that of its own node 13 and the like described here.
Therefore, in the description of the configuration and operation performed below with reference to FIG. 6, the failure detection time of each node is generally described without specifying.

  The failure localizing device 43 acquires the failure detection time of the downstream node 14, and when the failure detection time of the own node 13 is longer than the acquired time, the time acquired from the failure detection time of the own node 13 And waiting time elapses when a notification indicating that a failure has been detected is received from the downstream node 14 and the waiting time setting unit 50 that sets this calculation time as the waiting time t of the own node 13. And a failure occurrence detection unit 60 for detecting whether or not a failure has occurred on the upstream side.

  The waiting time setting unit 50 acquires the failure detection time from the downstream node 14 and compares the acquired failure detection time of the downstream node 14 with the failure detection time of the own node 13 to thereby detect the failure detection time of the own node 13. When the detection time determination unit 50A determines whether or not the adjacent downstream node 14 is longer than the adjacent downstream node 14, and the detection time determination unit 50A determines that the failure detection time of the own node 13 is longer, Wait time calculation processing means 50B for subtracting the failure detection time of the downstream node 14 from the failure detection time and storing the calculated time in an internal memory or the like (not shown) as a waiting time t specific to the own node 13; have.

  Here, when detecting whether or not a failure has occurred in the upstream, the detection cannot be performed accurately without waiting if the failure detection time of each node is longer than that of the adjacent downstream node. In the present embodiment, since the detection time determination unit 50A employed in view of this point functions effectively, the waiting time calculation processing unit 50B calculates and sets the waiting time t until the failure detection is determined as necessary. Can do.

  In addition, the waiting time setting unit 50 includes detection time notification means 50 </ b> C that notifies the failure localizing device 42 included in the upstream node 12 of the failure detection time of the own node 13. For this reason, the failure localizing device 42 can calculate and set the waiting time t peculiar to the upstream node 12 as necessary, and can accurately detect the presence / absence of failure on the upstream side using this. it can.

  When the failure detection unit 60 detects that a failure has occurred on the upstream side, the failure detection unit 60 notifies the upstream node 12 of the detection, and determines whether or not a failure has occurred in response to the notification from the upstream node 12. Based on such information, there is an occurrence location localizing means 60A for judging whether or not a failure has occurred in the section between the upstream node 12 and the own node 13.

In addition, the failure occurrence detection unit 60 includes a detection result response unit 60B that responds to the downstream node 14 with a detection result relating to the presence or absence of a failure when receiving a notification from the downstream node 14 that a failure has been detected. ing.
Upon receiving the notification from the detection result response means 60B, the failure localizing device 44 in the downstream node 14 generates a failure in the section between the own node 13 and the downstream node 14 located upstream based on the detection result. It can be accurately determined whether or not.

(Description of operation)
The operation of the failure localizing apparatus included in each node shown in FIG. 6 will be described based on the flowcharts shown in FIGS.

First, with reference to FIG. 7, the operation content when each node calculates the waiting time t will be described.
The detection time determination means 50A that acquired the failure detection time of the downstream node 14 (FIG. 7: S701) compares this acquired time with the failure detection time of the own node 13 to determine the failure detection time of the own node 13. It is determined whether it is longer than the downstream node 14 (FIG. 7: S702).

  When the detection time determination unit 50A determines that the failure detection time of the own node 13 is longer (FIG. 7: S702 / Yes), the waiting time calculation processing unit 50B determines that the downstream node 14 The failure detection time is subtracted, and this calculation time is set as a waiting time t specific to the own node 13 (FIG. 7: S703).

  On the other hand, when the detection time determination unit 50A determines that the failure detection time of the node 13 is not longer (FIG. 7: S702 / No), the waiting time calculation processing unit 50B does not perform any processing.

Next, with reference to FIG. 8, the operation content related to failure detection will be described.
When the waiting time calculation processing unit 50B calculates the waiting time t (FIG. 7: S703) by the above-described steps shown in FIG. 7, a failure occurs when a notification that a failure has been detected is received from the downstream node 14. The detection unit 60 (FIG. 8: S801) waits for the elapse of the waiting time t and detects whether or not a failure has occurred on the upstream side (FIG. 8: S802).

  At that time, when the occurrence of a failure is detected (FIG. 8: S802 / Yes), the failure occurrence detection unit 60 responds the detection result to the downstream node 14 by the detection result response means 60B (FIG. 8: S803).

  Further, the failure occurrence detection unit 60 notifies the upstream node 12 of the detection by the occurrence location localizing means 60A (FIG. 8: S804), and the failure occurrence responded to the notification from the upstream node 12 Whether or not a failure has occurred in the section with the upstream node 12 is determined based on the information regarding whether or not there is (FIG. 8: S805).

  On the other hand, if the detection time determination unit 50A determines that the failure detection time of the node 13 is not longer by the above-described steps shown in FIG. 7 (FIG. 7: S702 / No), the waiting time t is Since it is not calculated, immediately after receiving a notification that a failure has been detected from the downstream node 14 (FIG. 8: S801), the failure occurrence detection unit 60 detects whether or not a failure has occurred on the upstream side (FIG. 8: S802).

  At that time, when the occurrence of a failure is detected (FIG. 8: S802 / Yes), the failure occurrence detection unit 60 responds the detection result to the downstream node 14 by the detection result response means 60B (FIG. 8: S803). ).

  Further, the failure occurrence detection unit 60 notifies the upstream node 12 of the detection by the occurrence location localizing means 60A (FIG. 8: S804), and considers the response to this within the section with the upstream node 12. Whether or not a failure has occurred is determined (FIG. 8: S805).

  Further, even when the occurrence of a failure on the upstream side is not detected (FIG. 8: S802 / No), the failure occurrence detection unit 60 responds the detection result to the downstream node 14 by the detection result response means 60B ( FIG. 8: S806).

  In the above description, the operation has been described in which the failure detection unit 60 detects the presence or absence of a failure on the upstream side immediately after receiving a notification that a failure has been detected from the downstream node 14 (FIG. 8: S801). (FIG. 8: S802).

  However, depending on the length of time of failure detection of each node, the failure occurrence detection unit 60 generates a failure on the upstream side before receiving notification that the failure has been detected from the downstream node 14 (FIG. 8: S801). It will be detected whether or not. Therefore, immediately after receiving the notification that the failure has been detected from the downstream node 14, the failure occurrence detection unit 60 in this case responds to the downstream node 14 with the result of the detection performed in advance (FIG. 8: S803). .

  Next, the Fault Localization process of FIG. 2 will be described with reference to the sequence diagram shown in FIG.

First, the node 14 detects a failure occurring upstream (FIG. 1: S100), and notifies the node 13 of an SF notification by a CS message (CS (SF, D = 0)) (FIG. 1: S101). ).
Receiving this notification, the node 13 returns Ack (CS Ack) to notify the node 14 that the message has been received (FIG. 1: S102).

Next, the node 13 detects (checks) whether or not a failure has occurred on its upstream side after t seconds as the waiting time have elapsed (FIG. 1: S103). Thus, when a failure is detected (FIG. 1: S104), the node 13 transmits a (CS (SF, D = 1)) message to the node 14 (FIG. 1: S105).
In response to this, the node 14 returns Ack (CS Ack) to transmit to the node 13 that the message has been received (FIG. 1: S106).

  Through the above steps (steps S100 to S106), since both the node 13 and the node 14 have detected a failure on the upstream side, the node 14 accurately determines that there is no failure between the node 13 and the node 14. To do.

Next, the operation between the node 11 and the node 12 is as follows.
First, the node 12 that has detected a failure by detecting whether or not a failure has occurred on its upstream side (FIG. 1: S107), notifies the node 11 of the fact of the detection by a CS message (CS (SF, D = 0)) (FIG. 1: S108), the node 11 receiving this returns Ack (CS Ack) to the message and detects (checks) whether or not a failure has occurred on its upstream side (FIG. 1). : S109).

  Here, since no failure has occurred on the upstream side of the node 11, the node 11 transmits a (CS (OK, D = 1)) message indicating that no failure has occurred to the node 12 (FIG. 1: S110), the node 12 that has returned Ack (CS Ack) in response to this message has no failure on the upstream side of the node 11 and has a failure on the upstream side of the node 12, so there is a failure between the node 11 and the node 12. (FIG. 1: S111).

Subsequently, the operation between the node 12 and the node 13 is as follows.
First, the node 13 that has detected a failure by detecting whether or not a failure has occurred on its upstream side (FIG. 1: S104), notifies the node 12 of an SF notification by CS message (CS (SF, D = 0)) (FIG. 1: S112), and the node 12 receiving this returns Ack (CS Ack) for the message (FIG. 1: S113).

    As described above, the node 12 that detects the occurrence of a failure on its upstream side (FIG. 1: S107) transmits a message (CS (SF, D = 1)) indicating that a failure has occurred to the node 13 ( In FIG. 1: S114), the node 13 that has returned Ack (CS Ack) in response to this message (FIG. 1: S109), both nodes 12 and 13 have detected a failure on the upstream side. It is determined that there is no failure between 13.

Each of the above operations has been described in the order of the numbers given in FIG. 1 (S101 to S115), FIG. 7 (S701 to S703), and FIG. 8 (S801 to S806) for convenience. The operation contents of the network device and the transmission network system are not limited to this order.
In addition, the execution contents of each step in the above steps S101 to S115 (FIG. 1), S701 to S703 (FIG. 7), and FIG. 8 (S801 to S806) are programmed, and this series of control programs is executed by a computer. You may comprise so that it may implement | achieve.

(Effects of the embodiment, etc.)
In the transmission network system 30 according to the present embodiment, as described above, in the fault localization of LMP (Link Management Protocol), each node is notified in advance of the respective fault detection times in advance.
In other words, considering the time required to detect a failure (failure detection time) varies depending on the node, the failure detection time of each node is notified in advance between adjacent nodes when the control channel is established. Configured to fit.

  As a result, each node can acquire the failure detection time of the adjacent downstream node in advance, and therefore, using the standby time t calculated based on the acquired time and the failure detection time of the own node, It is possible to significantly adjust the timing of responses to notifications from the nodes, that is, since it is possible to correctly respond to the downstream node whether or not a failure has occurred (failure state), the downstream node receiving this correctly The generation interval can be determined.

  Therefore, in the transmission network system 30 according to the present embodiment, a configuration is adopted in which failure section determination by fault localization is performed at the stage where each node completes failure detection. Therefore, the downstream node precedes the upstream node. The problem of misjudgment caused by detecting a failure can be solved, and thereby the failure occurrence section can be correctly determined in the entire system.

  Further, the calculation and setting of the waiting time t until the failure detection is confirmed is automatically performed by each node when the control channel is established, so that the convenience of the user can be achieved.

  In the present embodiment, the configuration and operation of the transmission network system illustrated in FIG. 1 and the like are described in the direction of signals from the node 11 to the node 14. However, even when a signal that is user traffic is transmitted in the direction from the node 14 to the node 11, each node (each fault localization device) and the transmission network system according to the present embodiment function in the same manner as described above. Similar effects can be obtained.

  Note that the above-described embodiments are preferred specific examples of the failure localization apparatus, the transmission network system, the failure localization method, and the program thereof, and may have various technically preferable limitations. However, the technical scope of the present invention is not limited to these embodiments unless specifically described to limit the present invention.

  The following summarizes the main points of the new technical contents of the above-described embodiment, but the present invention is not necessarily limited to this.

(Appendix 1)
In a transmission network system in which a plurality of nodes communicate with each other, it is generated in the section with the upstream node based on the information obtained by the communication with the adjacent upstream and downstream nodes that are equipped in each node. A fault localization device for detecting faults, comprising:
When the failure detection time of the own node is longer than the failure detection time of the downstream node, the failure detection time of the downstream node is subtracted from the failure detection time of the own node, and the calculated time is used as the waiting time of the own node. A waiting time setting section to be set as
A failure occurrence detection unit that detects whether or not a failure has occurred on the upstream side after waiting for the elapse of the waiting time when receiving a notification that a failure has been detected from the downstream node; Localization device.

(Appendix 2)
In the failure localizing apparatus according to the appendix 1,
When the failure occurrence detection unit detects that a failure has occurred on the upstream side, the failure occurrence detection unit notifies the upstream node of the detection, and whether or not a failure has occurred is responded to the notification from the upstream node. A failure localizing apparatus, comprising: an occurrence location localizing unit that determines whether or not a failure has occurred in a section with the upstream node based on the information related to

(Appendix 3)
In the failure localizing apparatus according to the appendix 1 or 2,
The failure occurrence detection unit further comprises detection result response means for responding to the downstream node with a detection result relating to the presence or absence of the failure when receiving a notification that a failure has been detected from the downstream node. Feature failure localization device.

(Appendix 4)
A transmission network system including a plurality of nodes communicating with each other,
Each of the nodes has a failure localization device that detects a failure that occurs in a section with the upstream node based on information obtained by the communication with the adjacent upstream and downstream nodes,
A transmission network system comprising the failure localization device according to any one of the supplementary notes 1 to 3 as the failure localization device.

(Appendix 5)
In a transmission network system in which a plurality of nodes communicate with each other, it is generated in the section with the upstream node based on the information obtained by the communication with the adjacent upstream and downstream nodes that are equipped in each node. In a fault localization device that detects faults,
Obtaining the failure detection time of the downstream node;
When the failure detection time of the own node is longer than the acquired time, the acquired time is subtracted from the failure detection time of the own node, and the calculated time is set as the waiting time of the own node,
A failure localization method, comprising: detecting a failure occurrence on the upstream side after waiting for the elapse of the waiting time when receiving a notification that a failure has been detected from the downstream node.

(Appendix 6)
In the failure localization method according to Appendix 5,
When it is detected that a failure has occurred on the upstream side, the upstream node is notified of the detection, and
Failure localization characterized by determining whether or not a failure has occurred in the section with the upstream node based on information on whether or not a failure has occurred that is responded to from the upstream node in response to this notification Method.

(Appendix 7)
In the failure localization method according to the above supplementary note 5 or 6,
When receiving a notification that a failure has been detected from the downstream node, a failure localization method characterized by responding to the downstream node with a detection result relating to the presence or absence of the failure.

(Appendix 8)
In a transmission network system in which a plurality of nodes communicate with each other, it is generated in the section with the upstream node based on the information obtained by the communication with the adjacent upstream and downstream nodes that are equipped in each node. In a fault localization device that detects faults,
When the failure detection time of the own node is longer than the failure detection time of the downstream node, the failure detection time of the downstream node is subtracted from the failure detection time of the own node, and the calculated time is used as the waiting time of the own node. Wait time setting means to set as
A failure occurrence detection means for detecting the occurrence of failure on the upstream side after waiting for the elapse of the waiting time when receiving a notification that a failure has been detected from the downstream node;
A fault localization program for causing a computer provided in advance in the fault localization apparatus to function.

(Appendix 9)
In the failure localization program according to appendix 8,
The computer,
When the occurrence of a failure is detected by the failure occurrence detection means, when the occurrence of the failure is detected, the upstream node is notified of the detection, and the upstream node is responded to this notification. A failure localization program for functioning as an occurrence location localizing unit that determines whether or not a failure has occurred in a section with the upstream node based on information on whether or not a failure has occurred.

(Appendix 10)
In the failure localization program according to the appendix 8 or 9,
The computer,
A failure localization program for causing a result detected by the failure occurrence detection unit to function as a detection result response unit that responds to the downstream node when receiving a notification that a failure has been detected from the downstream node.

  INDUSTRIAL APPLICABILITY The present invention can be used in the technical field of detecting the occurrence of a failure in LMP Fault Localization.

11 nodes 12 nodes (upstream node)
13 nodes (own node)
14 nodes (downstream nodes)
DESCRIPTION OF SYMBOLS 20 Control plane 30 Transmission network system 42, 43, 44 Fault localization apparatus 50 Wait time setting part 50A Detection time determination means 50B Wait time calculation processing means 50C Detection time notification means 60 Fault occurrence detection part 60A Occurrence location localization means 60B detection Result response means 101, 102, 103, 104, 201, 202, 203, 204 nodes

Claims (10)

In a transmission network system in which a plurality of nodes communicate with each other, it is generated in the section with the upstream node based on the information obtained by the communication with the adjacent upstream and downstream nodes that are equipped in each node. A fault localization device for detecting faults, comprising:
When the failure detection time of the own node is longer than the failure detection time of the downstream node, the failure detection time of the downstream node is subtracted from the failure detection time of the own node, and the calculated time is used as the waiting time of the own node. A waiting time setting section to be set as
A failure occurrence detection unit that detects whether or not a failure has occurred on the upstream side after waiting for the elapse of the waiting time when receiving a notification that a failure has been detected from the downstream node; Localization device. The fault localization apparatus according to claim 1,
When the failure occurrence detection unit detects that a failure has occurred on the upstream side, the failure occurrence detection unit notifies the upstream node of the detection, and whether or not a failure has occurred is responded to the notification from the upstream node. A failure localizing apparatus, comprising: an occurrence location localizing unit that determines whether or not a failure has occurred in a section with the upstream node based on the information related to In the fault localization apparatus according to claim 1 or 2,
The failure occurrence detection unit further comprises detection result response means for responding to the downstream node with a detection result relating to the presence or absence of the failure when receiving a notification that a failure has been detected from the downstream node. Feature failure localization device. A transmission network system including a plurality of nodes communicating with each other,
Each of the nodes has a failure localization device that detects a failure that occurs in a section with the upstream node based on information obtained by the communication with the adjacent upstream and downstream nodes,
A transmission network system comprising the failure localization device according to any one of claims 1 to 3 as the failure localization device. In a transmission network system in which a plurality of nodes communicate with each other, it is generated in the section with the upstream node based on the information obtained by the communication with the adjacent upstream and downstream nodes that are equipped in each node. In a fault localization device that detects faults,
Obtaining the failure detection time of the downstream node;
When the failure detection time of the own node is longer than the acquired time, the acquired time is subtracted from the failure detection time of the own node, and the calculated time is set as the waiting time of the own node,
A failure localization method, comprising: detecting a failure occurrence on the upstream side after waiting for the elapse of the waiting time when receiving a notification that a failure has been detected from the downstream node. In the failure localization method according to claim 5,
When it is detected that a failure has occurred on the upstream side, the upstream node is notified of the detection, and
Failure localization characterized by determining whether or not a failure has occurred in the section with the upstream node based on information on whether or not a failure has occurred that is responded to from the upstream node in response to this notification Method. In the failure localization method according to claim 5 or 6,
When receiving a notification that a failure has been detected from the downstream node, a failure localization method characterized by responding to the downstream node with a detection result relating to the presence or absence of the failure. In a transmission network system in which a plurality of nodes communicate with each other, it is generated in the section with the upstream node based on the information obtained by the communication with the adjacent upstream and downstream nodes that are equipped in each node. In a fault localization device that detects faults,
When the failure detection time of the own node is longer than the failure detection time of the downstream node, the failure detection time of the downstream node is subtracted from the failure detection time of the own node, and the calculated time is used as the waiting time of the own node. Wait time setting means to set as
A failure occurrence detection means for detecting the occurrence of failure on the upstream side after waiting for the elapse of the waiting time when receiving a notification that a failure has been detected from the downstream node;
A fault localization program for causing a computer provided in advance in the fault localization apparatus to function. In the failure localization program according to claim 8,
The computer,
When the occurrence of a failure is detected by the failure occurrence detection means, when the occurrence of the failure is detected, the upstream node is notified of the detection, and the upstream node is responded to this notification. A failure localization program for functioning as an occurrence location localizing unit that determines whether or not a failure has occurred in a section with the upstream node based on information on whether or not a failure has occurred. In the failure localization program according to claim 8 or 9,
The computer,
A failure localization program for causing a result detected by the failure occurrence detection unit to function as a detection result response unit that responds to the downstream node when receiving a notification that a failure has been detected from the downstream node.

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