JP2011066484A - Fault portion identifying method in packet ring network, and system for executing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily identifying a fault portion of a packet ring network. <P>SOLUTION: Drop interfaces of N-units of node devices constituting a ring each have: a first transmission point for periodically transmitting a connection check message to be transferred clockwise in the ring; a second transmission point for periodically transmitting a connection check message to be transferred counterclockwise in the ring; a first reception-confirming point for confirming the reception of the connection check message transmitted from the first transmission point of a node device on an upstream by k clockwise; and a second reception-confirming point for confirming the reception of the connection check message transmitted from the second transmission point of a node device on an upstream by k counterclockwise. With this configuration, a fault portion is determined on the basis of the communication state detected by the first and second reception confirming points. Here, N is a natural number of ≥3, and k is a natural number of ≥2 and ≤(N-1) except N/2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for efficiently identifying a fault location in a packet ring network.

  The maintenance operation management function of Ethernet (registered trademark) is defined in Non-Patent Documents 1, 2, and 3, and a bridge device and a packet processing device for a network having a ring configuration such as RPR (Resilient Packet Ring) have already been provided. It is commercially available.

ITU-T Y.M. 1731, “OAM functions and Mechanisms for Ethernet Based Networks” IEEE802.1ag, “Connectivity Fault Management” IEEE802.1Qaw, “Management of data-drive and data-dependent connectivity faults”

  FIG. 1 is a diagram showing a schematic configuration of a packet ring network. Reference numerals 0 to 5 denote bridge devices or packet processing devices (hereinafter simply referred to as node devices) each implementing a protocol for ring configuration. The arrows between the node devices represent transmission paths.

  FIG. 2 is a schematic configuration diagram of each node device, and each node device includes two line interfaces 11 and 12 and a drop interface 13. Each line interface 11 and 12 is connected to a line interface of a node device adjacent in a ring configuration by a transmission path. The drop interface 13 is an interface for packets input to the ring and packets output from the ring.

  The connectivity inspection function, which is one of the maintenance operation management functions, refers to periodically transmitting a connectivity inspection message (CCM) from a certain point in the network and confirming reception of this CCM at another point. It is done by. Normally, this point can be set in each direction at each interface.

  The connectivity check detects whether or not communication between the set CCM transmission point and the CCM reception point (hereinafter referred to as a connectivity check section) is secured. It does not specify the fault location in the examination section. However, it is convenient if a plurality of connectivity inspection sections are set and a fault location can be determined based on the communication status of each connectivity inspection section.

  Accordingly, an object of the present invention is to provide a method and system for identifying a failure point in a packet ring network using a connectivity check function.

A method for identifying a fault location in a packet ring network according to the present invention includes:
A first transmission point for periodically transmitting a connection check message forwarded in the clockwise direction to the drop interface of each of the N node apparatuses constituting the ring, and a counterclockwise direction in the ring A second transmission point for periodically transmitting a connection check message forwarded to the node device is provided, and is transmitted from the first transmission point of the node device upstream by k in the clockwise direction to the drop interface of each node device. A first reception confirmation point for confirming the reception of the connection inspection message and a second confirmation of reception of the connection inspection message transmitted from the second transmission point of the node device upstream by k in the counterclockwise direction. A reception confirmation point is provided, and the failure location is determined based on the communication state detected by the first and second reception confirmation points. Is a natural number of 3 or more, k except the N / 2, wherein the N-1 following a natural number of 2 or more.

According to another embodiment of the method of the present invention,
The failure location to be determined is the output direction failure of the drop interface of the node device, the input direction failure of the drop interface of the node device, the clockwise transmission line between the node devices and the clockwise rotation of the line interface connected to the transmission line Directional failure, counterclockwise direction transmission path between node devices and the line interface connected to the transmission path, clockwise failure at the transfer portion between line interfaces of node devices, node device line -It is also preferred that it is one of counterclockwise obstructions at the connection between the interfaces.

The system according to the invention comprises:
The packet transfer is performed, N node devices having two line interfaces and one drop interface are connected, and the line interface of each node device is connected to the line interface of another node device. In a system having a ring configuration, a drop interface of each node device includes a first transmission point for periodically transmitting a connection check message transferred in a clockwise direction in the ring, and a counterclockwise in the ring. A second transmission point for periodically transmitting a connection check message forwarded in the forward direction, a first reception confirmation point for confirming reception of a connection check message forwarded in the clockwise direction in the ring, and in the ring And a second reception confirmation point for confirming reception of the connection inspection message transferred in the counterclockwise direction. The first reception confirmation point of each node device confirms the reception of the connection check message transmitted from the first transmission point of the node device that is upstream by k in the clockwise direction. The communication with the first transmission point of the node device upstream by k is confirmed, and the second reception confirmation point of each node device is the second transmission of the node device upstream by k in the counterclockwise direction. By confirming the reception of the connection check message transmitted from the point, communication with the second transmission point of the node device upstream by k in the counterclockwise direction is confirmed, and N is a natural number of 3 or more, k is a natural number of 2 or more and N-1 or less excluding N / 2.

According to another embodiment of the system of the present invention,
It is also preferable to further include a management device that collects information about communication states detected by the first and second reception confirmation points from each node device and determines a failure location. Further, k is preferably N-1.

  When the reception confirmation point detects a disconnection, it is possible to easily narrow down the fault location.

It is a figure which shows the schematic structure of a packet ring network. It is a schematic block diagram of each node apparatus. It is a figure which shows a failure location. It is a figure which shows the connectivity test | inspection area to set. It is a figure which shows the connectivity test | inspection area which detects a connection disconnection with respect to the failure location shown in FIG. It is a figure which shows the connectivity test | inspection area set in other embodiment. In other embodiment, it is a figure which shows the connectivity test | inspection area which detects a disconnection with respect to the failure location shown in FIG.

  EMBODIMENT OF THE INVENTION The form for implementing this invention is demonstrated in detail below using drawing. In the following description, a node device upstream by k in a clockwise direction from a certain node device means a device that is k previous in the clockwise direction and is downstream by k in the clockwise direction. The node device means a device that is k times behind a certain node device in the clockwise direction. Specifically, in the configuration of FIG. 1, the node device that is one upstream in the clockwise direction from the node device 3 is the node device 2, and the node device that is two upstream in the clockwise direction from the node device 3 is the node In the device 1, the node device that is one downstream in the clockwise direction from the node device 3 is the node device 4, and the node device that is two downstream in the clockwise direction from the node device 3 is the node device 5.

  Similarly, a node device upstream by k in a counterclockwise direction from a certain node device means a device preceding by k from a certain node device in the counterclockwise direction, and a node downstream by k in the counterclockwise direction. A device means a device after k from a certain node device in the counterclockwise direction. Specifically, in the configuration of FIG. 1, the node device one upstream in the counterclockwise direction from the node device 3 is the node device 4, and the node device one downstream in the counterclockwise direction from the node device 3. Is the node device 2. Since the ring configuration, for example, two upstream devices in the clockwise direction from the node device 3, four downstream devices in the clockwise direction from the node device 3, and two in the counterclockwise direction from the node device 3. The two downstream devices and the four upstream devices in the counterclockwise direction from the node device 3 all indicate the same node device 1.

  In the present invention, the drop interface of each node device is related to the inspection of four connectivity inspection sections. Of the four connectivity tests, two are on the side that transmits the CCM, and the remaining two are on the side that confirms the reception of the CCM. That is, two CCM transmission points and two CCM reception confirmation points are set in the drop interface of each node device. Therefore, in the present invention, it is not necessary to provide a CCM transmission point and a CCM reception confirmation point in the line interface.

  Both CCM transmission points both send CCMs to the ring network side, but CCMs from one CCM transmission point are forwarded clockwise in the ring network and CCMs from the other CCM transmission point are ring Set each CCM transmission point so that it is transferred counterclockwise in the network.

  Also, one CCM reception confirmation point of the two CCM reception confirmation points set in each node device is within the ring in the clockwise direction from the CCM transmission point set in the node device one downstream in the clockwise direction. The other CCM reception confirmation point is transferred in the counterclockwise direction from the CCM transmission point set in the node device one downstream in the counterclockwise direction. Confirmation of the received CCM is performed.

  FIG. 4 is a diagram showing each connectivity inspection section set for the ring network shown in FIG. 1, in which white triangles indicate CCM transmission points and black triangles indicate CCM reception confirmation points. As described above, the position is a drop interface.

  FIG. 5 shows a connectivity inspection section in which a disconnection is detected when a failure occurs at locations indicated by A to F in FIG. 3 when the connectivity inspection section shown in FIG. 4 is set. The direction is the direction in which the CCM is transferred within the ring. Each CCM reception confirmation point is classified into one that performs CCM reception confirmation in the clockwise direction and one that performs CCM reception confirmation in the counterclockwise direction, and the direction is specified from the CCM reception confirmation point that detected the disconnection. Is possible.

  As shown in FIG. 5, when a failure occurs in node device 2 A, a disconnection is detected at both of the two CCM reception confirmation points corresponding to the clockwise and counterclockwise directions of node device 2. Further, when a failure occurs in B of the node device 2, disconnections in different directions are detected at the CCM reception confirmation points of the adjacent node devices 1 and 3 respectively. That is, when connection disconnection is detected at two CCM reception confirmation points of the same node device, it can be determined as an output direction failure in the drop interface of the node device. When a disconnection in a different direction is detected at each CCM reception confirmation point, it can be determined that this is an input direction failure in the drop interface of the certain node device.

  Further, when the failure location is C, that is, when a failure occurs in the transmission path from the node device 2 to the node device 3, the CCM reception confirmation point corresponding to the clockwise direction of all the node devices except the node device 2 is used. A disconnection is detected. Similarly, when the failure location is D, that is, when a failure occurs in the transmission path from the node device 3 to the node device 2, the CCM reception confirmation corresponding to the counterclockwise direction of all the node devices except the node device 3 is confirmed. A disconnection is detected at a point. That is, when a disconnection is detected at a CCM reception confirmation point corresponding to the same direction of all the node devices other than a certain node device, one node device in the detected direction is detected from the node device that has not detected the disconnection. It can be determined that there is a failure in the transmission path to the node device on the downstream side and the line interface connected to this transmission path.

  Next, a case where a failure occurs in a transfer portion between line interfaces, that is, E and F in FIG. 3 will be described. When the failure location is E, the disconnection is detected at the CCM reception confirmation point corresponding to the clockwise direction of all the node devices except the node devices 1 and 2. Similarly, when the failure location is F, disconnection is detected at the CCM reception confirmation point corresponding to the counterclockwise direction of all the node devices except the node devices 2 and 3. That is, when a disconnection is detected at the CCM reception confirmation point corresponding to the same direction of all the node devices other than two consecutive node devices, in the detected direction of the two node devices not detected It can be determined that there is a failure in the transfer part between the line interfaces in the node device on the downstream side. Note that the direction matches the direction in which the disconnection is detected.

  FIG. 6 is a diagram showing connectivity inspection sections in another embodiment of the present invention. In this embodiment, the CCM reception confirmation point for confirming the CCM in the clockwise direction confirms the CCM from the CCM transmission point in the node device two upstream in the clockwise direction, and confirms the CCM in the counterclockwise direction. The CCM reception confirmation point to be confirmed confirms the CCM from the CCM transmission point in the node device two upstream in the counterclockwise direction.

  FIG. 7 shows a connectivity inspection section in which a disconnection is detected when a failure occurs at the failure location shown in FIG. 3 when the connectivity inspection section shown in FIG. 6 is set. As shown in FIG. 7, when a failure occurs in A of the node device 2, a disconnection is detected at both of the two CCM reception confirmation points corresponding to the clockwise and counterclockwise rotation of the node device 2. Further, when a failure occurs in B of the node device 2, the connection is disconnected at the CCM reception confirmation point corresponding to the clockwise direction of the node device 4 and the CCM reception confirmation point corresponding to the counterclockwise direction of the node device 0. Detected. That is, when connection disconnection is detected at two CCM reception confirmation points of the same node device, it can be determined as an output direction failure in the drop interface of the node device.

  Further, when a disconnection is detected at each of the CCM reception confirmation point corresponding to the clockwise direction and the CCM reception confirmation point corresponding to the counterclockwise direction, the node device that detected the connection disconnection in the detected direction. It is determined whether or not the node devices on the upstream side are the same by the connection length. If they are the same, it can be determined that there is an input direction failure in the drop interface of this node device. Here, the connection length of the connectivity inspection section is a value obtained by subtracting 1 from the node device included in the connectivity inspection section. That is, in the present embodiment, the connection length is 2, and the node device that is two upstream of the node device 4 in the clockwise direction and the node device that is two upstream of the node device 0 in the counterclockwise direction are Therefore, it can be determined that the node device 2 is an input direction failure in the drop interface of the node device 2.

  When the fault location is C, disconnection is detected at the CCM reception confirmation point corresponding to the clockwise direction, but the node devices to be detected are arranged consecutively, and the number thereof is the connection length. Is equal to Similarly, when the fault location is D, disconnection is detected at the CCM reception confirmation point corresponding to the counterclockwise direction, but the node devices to be detected are continuously arranged, and the number thereof is connected. Equal to the length. Here, if the node device that is one upstream in the detected direction is not the node device that has detected the disconnection among the consecutive node devices that have detected the disconnection, this node device is referred to as the “continuous that has detected the disconnection”. The node device that is the most upstream in the detected direction ”is defined. For example, when the disconnection is detected in the node devices 5, 0, 1, and 2 in the clockwise direction, the node devices one upstream of the node devices 0, 1, and 2 are respectively connected to the node devices 5, 0, and 1 is a node device 4 that has detected a disconnection but one upstream of the node device 5 is a node device 4 that has not detected a disconnection. Therefore, the node device 5 is the most upstream node device. is there.

  When the fault location is C or D, the disconnection is detected by the continuous node devices. Among these, the upstream node device in the detected direction has a line interface for receiving the faulty transmission path. Represents a node device. In other words, when the failure location is C, the disconnection is detected by the node devices 3 and 4, but the transmission line in the clockwise direction that is input to the most upstream node device 3 in the clockwise direction can be identified as the failure. Similarly, when the fault location is D, disconnection is detected by the node devices 1 and 2, but the transmission path in the counterclockwise direction input to the most upstream node device 2 in the counterclockwise direction can be identified as the fault. .

  Also, in the case of a failure in the transfer part between the line interface, a disconnection is detected at the CCM reception confirmation point corresponding to the same direction as the failure direction, but the number is one less than the connection length. . In addition, the node device that has failed becomes a node device that is one upstream in the detected direction from the node device that is most upstream of the node device that detected the disconnection. That is, when the failure location is E, the node device 3 detects a disconnection, but it can be identified as a failure in the transfer portion between the line interfaces of the node device 2 that is one upstream of the node device 3 in the clockwise direction. . Similarly, when the failure location is F, the node device 1 detects a disconnection, but the transfer portion between the line interface of the node device 2 upstream of the node device 1 in the counterclockwise direction Can be identified.

  As is clear from the above two embodiments, in the present invention, the clockwise direction of the ring network with respect to the drop interface of N node devices (N is a natural number of 3 or more) constituting the ring network. A CCM transmission point for transmitting CCM and a CCM transmission point for transmitting CCM in the counterclockwise direction of the ring network are provided. In addition, for the drop interface of each node device, a CCM reception confirmation point for confirming reception of the CCM transferred in the clockwise direction through the ring network, and a CCM received in the counterclockwise direction through the ring network. A CCM reception confirmation point for performing reception confirmation is provided.

  Here, the CCM reception confirmation point for the CCM transferred in the clockwise direction of each node device monitors the CCM transmitted by the CCM transmission point of the node device upstream by k in the clockwise direction, and the response of each node device. The CCM reception confirmation point for the CCM transferred in the clockwise direction monitors the CCM transmitted by the CCM transmission point of the node device upstream by k in the counterclockwise direction. Here, k is a natural number of 2 or more and N-1 or less, and is a value excluding N / 2. Note that k corresponds to the connection length described above. Here, k = 1 is not possible because it is not possible to detect a failure in the connection part between the line interfaces such as the failure points E and F in FIG. 3, and k = N / 2 is excluded because of the failure in FIG. This is because the locations A and B cannot be distinguished.

  In the above setting, when connection disconnection is detected at two CCM reception confirmation points of a certain node device, it can be determined that there is a failure in the output direction of the drop interface of that node device. In addition, when a disconnection is detected at a CCM reception confirmation point corresponding to a clockwise direction of a certain node device and a CCM reception confirmation point corresponding to a counterclockwise direction of another node device, each of the node devices that detected the disconnection If a node device that is upstream by k in the detection direction is specified, and this node device is the same node device in both directions, it can be determined that this node device has a drop interface input direction failure. If they do not match, it is a multiple failure.

  In addition, if a disconnection is detected at a CCM reception confirmation point corresponding to the same direction of consecutive k node devices, it is a transmission path or line interface failure, and the transmission path and line interface are As described above, the determination can be made from the direction that is detected and the node device that is the most upstream among the node devices that detect the disconnection.

  Furthermore, if a disconnection is detected at a CCM reception confirmation point corresponding to the same direction of consecutive k−1 node devices, it is a failure in a portion connecting line interfaces of a certain node device, As described above, the faulty node device can be determined from the detecting direction and the most upstream node device detecting the disconnection.

  In the setting shown in FIG. 6, if a failure in the node device 3 corresponding to E in FIG. 3 and a failure in the node device 1 corresponding to F in FIG. It will be erroneously determined as a failure. In order to avoid the possibility of erroneous determination and to determine that a multiple failure is a multiple failure, it is desirable that the value of k is large. In particular, in the case of k = N−1, as described with reference to FIGS. 4 and 5, for the transmission line break that occurs most frequently, the CCM reception confirmation point that has not detected the transmission line break is the failure section. Therefore, it is desirable that k = N−1.

  With the above configuration, the connection state detected by the two reception confirmation points of each node device constituting the ring network, that is, information on the connection state or the disconnection state is taken into a network management device (not shown), and the network management device By using the method described above, it is possible to quickly identify the fault location.

0, 1, 2, 3, 4, 5 Node equipment 11, 12 Line interface 13 Drop interface

Claims (5)

A method for identifying a failure point in a packet ring network,
A first transmission point for periodically transmitting a connection check message forwarded in the clockwise direction to the drop interface of each of the N node apparatuses constituting the ring, and a counterclockwise direction in the ring Providing a second transmission point for periodically transmitting a connection check message forwarded to
A first reception confirmation point for confirming reception of a connection check message transmitted from the first transmission point of the node device upstream by k in the clockwise direction, and a counterclockwise direction on the drop interface of each node device Providing a second reception confirmation point for confirming reception of the connection check message transmitted from the second transmission point of the node device upstream by k,
Based on the communication state detected by the first and second reception confirmation points, the failure location is determined,
A method in which N is a natural number of 3 or more, and k is a natural number of 2 or more and N-1 or less, excluding N / 2.   The failure location to be determined is the output direction failure of the drop interface of the node device, the input direction failure of the drop interface of the node device, the clockwise transmission line between the node devices and the clockwise rotation of the line interface connected to the transmission line Directional failure, counterclockwise direction transmission path between node devices and the line interface connected to the transmission path, clockwise failure at the transfer portion between line interfaces of node devices, node device line The method according to claim 1, wherein any of the counterclockwise obstructions of the connection between the interfaces. Forwarding the packet, having N node devices with two line interfaces and one drop interface,
A system in which the line interface of each node device is connected to the line interface of another node device in a ring configuration,
The drop interface of each node device has a first transmission point for periodically transmitting a connection check message transferred in the clockwise direction in the ring, and a connection check message transferred in the counterclockwise direction in the ring. Is transmitted periodically, a first reception confirmation point for confirming reception of a connection check message forwarded in the ring in the clockwise direction, and forwarded in the counterclockwise direction in the ring. And a second reception confirmation point for confirming reception of the connection check message,
The first reception confirmation point of each node device confirms the reception of the connection check message transmitted from the first transmission point of the node device upstream by k in the clockwise direction, so that only k in the clockwise direction is obtained. Confirm communication with the first transmission point of the upstream node device,
The second reception confirmation point of each node device performs counterclockwise direction by confirming reception of the connection check message transmitted from the second transmission point of the node device upstream by k in the counterclockwise direction. And confirms communication with the second transmission point of the node device upstream by k,
A system in which N is a natural number of 3 or more, and k is a natural number of 2 or more and N-1 or less, excluding N / 2.   The system according to claim 3, further comprising: a management device that collects information about communication states detected by the first and second reception confirmation points from each node device and determines a failure location.   The system according to claim 3 or 4, wherein k is N-1.

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