JP2013157682A - Ring connection node, multiring network, and route switching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform more appropriate route switching than before when a multiple fault including one in a shared link occurs in a multiring network.SOLUTION: A ring connection node adaptable to a multiring network in which ring networks, each having a plurality of node devices connected in ring form, are interconnected so as to form a shared link comprises: a shared link fault detection unit 27 which detects a fault in a shared link; a major ring fault detection unit 26 which detects a fault in a link other than the shared links which is included in one of the ring networks set for a major ring; and a settings changeover unit 28 which, on the basis of the result of fault detection by the shared link fault detection unit 27 and the major ring fault detection unit 26, sets for a major ring another one of the ring networks which includes a shared link having a detected fault and is not set for a major ring.

Description

  The present invention relates to a multi-ring network in which a plurality of ring networks in which a plurality of node devices are connected in a ring shape are connected, a ring connection node that is used in the multi-ring network and connects the plurality of ring networks, and a path of the multi-ring network The switching method.

  In a ring network in which a plurality of node devices are connected in a ring shape, a part of the link of the ring network is blocked by blocking a port of one node device in the ring network in order to avoid occurrence of a loop in the ring network. Is operated in a logically disconnected state. Also, a method has been proposed in which when a failure occurs on the ring network, the blocked port is released and the communication path is switched so as to bypass the failure.

  For example, in ERP (Ethernet (registered trademark) Ring Protection), which is a protection standard for Ethernet (registered trademark) rings, one node device (Ring Protection Link owner, hereinafter referred to as RPL owner) in each ring network constituting a multi-ring network. Block), the link on the blocked port side is logically disconnected, and the occurrence of a normal loop is avoided. When a failure occurs, the node device that detected the failure closes the port on which the failure is detected, and a failure notification control frame (Ring-Automatic Protection Switching frame, hereinafter referred to as R-APS frame) is already created. Send from one port. When the RPL owner node receives the control frame, path switching is performed by releasing the port of the node device that previously blocked one port (for example, see Non-Patent Document 1).

  In the ERP multi-ring network, when two ring networks are connected, one is set as a closed loop shaped major ring and the other is set as an open loop shaped sub-ring. Here, a major ring is a ring network that performs failure management of a link (shared link) shared by a plurality of ring networks, and a sub-ring is a ring network that does not perform this failure management. When the major ring and the sub-ring are not set in this way, the shared link failure management is performed in both rings when the shared link failure occurs. That is, the previously blocked port of the RPL owner node is released in both ring networks, and a loop that spans both ring networks occurs. Therefore, major rings and sub-rings are set for multiple ring networks, and when a shared link failure occurs, only the major ring performs failure management and implements a protection operation that performs path switching to avoid the occurrence of loops. ing.

ITU-T G. 8032 Ethernet (registered trademark) Ring Protection Switching (ERP)

  However, if there are multiple failures in the major ring including failures in the shared link, that is, failures in the shared link and failures in links other than the shared link, no failure has occurred in the sub-ring as described above. Therefore, the blocked port in the sub-ring is not released. If multiple failures including a shared link occur in the major ring, the major ring and sub-ring are independent even though a physical detour exists. Since the protection is performed, the protection does not operate in the sub-ring, and the network is divided.

  This will be described with reference to FIG. As shown in FIG. 23, when a multiple failure including a failure in a shared link occurs, a failure in the shared link is detected in the ring connection node, the port on the link side where the failure has occurred is blocked, and the RPL owner node on the major ring side The block of the port set in advance in one of the ports is released. On the other hand, the node devices on both sides of the location where the failure has occurred in the major ring detect another failure and block the link side port where the failure is detected. Here, even though there is a physical detour by releasing a port previously blocked by the RPL owner node in the sub-ring, the protection does not operate in the sub-ring and the network is divided. It becomes.

  The present invention has been made to solve the above-described problems. Even when a multiple failure including a failure in a shared link occurs in a multi-ring network, the failure is bypassed and more appropriate route switching is performed. The purpose is to do.

  The ring connection node according to the present invention includes a plurality of node devices, and a plurality of ring networks forming a link between adjacent node devices are connected to each other so as to form a shared link having ring connection nodes at both ends, Multiple ring networks are set so that a specific link among the links included in the local ring network is logically disconnected, and a specific ring network of the multiple ring networks is detected as a failure detection result on the shared link. Based on a ring connection node that can be applied to a multi-ring network set in advance for a major ring that releases a logical disconnection of a link included in the own ring network, and that is included in the ring network set for the major ring Shared link failure detection unit that detects link failures , A major fault detection unit that detects a fault of a link that is included in the ring network configured as a major ring and that excludes shared links, and a fault based on the fault detection results of the shared link fault detection unit and the major ring fault detection unit A setting replacement unit configured to set the other ring network including the shared link detected as a major ring but not set to the major ring.

  The multi-ring network according to the present invention includes a plurality of node devices, and a plurality of ring networks forming links between adjacent node devices are connected to each other so as to form a shared link having ring connection nodes at both ends. The multiple ring networks are configured such that a specific link among the links included in the own ring network is logically disconnected, and a specific ring network of the multiple ring networks detects a failure in the shared link. Based on the results, a multi-ring network configured in a major ring that releases a logical link disconnection, and a shared link failure detection unit that detects a failure of a shared link included in the ring network configured in the major ring; Ring network configured as a major ring Measured failure detection unit that detects a failure of a link that is included and excludes a shared link, and includes a shared link in which a failure is detected based on the failure detection results of the shared link failure detection unit and the majoring failure detection unit A setting replacement unit that sets other ring networks that are not set to major ring as a major ring, and a link disconnection cancellation unit that cancels logical disconnection of a preset link of the ring network set as a major ring by the setting replacement unit And comprising.

In addition, the path switching method according to the present invention includes a plurality of node devices, and forms a shared link having ring connection nodes at both ends by mutually connecting a plurality of ring networks forming links between adjacent node devices. The plurality of ring networks are set in advance so as to logically disconnect a specific link included in the own ring network. Among the plurality of ring networks, the specific ring network is based on a failure detection result in the shared link. A shared link failure detection step for detecting a failure of the ring network set to the major ring, the path switching method applicable to the multi-ring network set to the major ring for releasing the logical disconnection of the link, Included in the ring network configured for major ring, Based on the failure detection results of the major failure detection step that detects the failure of links other than existing links and the failure detection results of the shared link failure detection step and the major failure detection step, the failure is detected and the shared link that has detected the failure is set to the major ring. A setting replacement step for setting another ring network that is not a major ring, a link disconnection cancellation step for canceling a logical disconnection of a preset link of the ring network set as a major ring in the setting replacement step,
Is provided.

  According to the present invention, even when a multiple failure including a failure in a shared link occurs in a multi-ring network, it is possible to perform a more appropriate failure detour and to improve the fault tolerance.

It is a block diagram of the multi-ring network shown in Embodiment 1 of this invention. It is a block diagram of the ring connection node in the multi-ring network shown in Embodiment 1 of this invention. It is a block diagram showing the input / output of the port A transmission / reception control part shown in Embodiment 1 of this invention. It is a block diagram showing the input / output of the port C transmission / reception control part shown in Embodiment 1 of this invention. It is a block diagram showing the input / output of the ring A-ERP control part shown in Embodiment 1 of this invention. It is a block diagram showing the input / output of the multiple failure management part shown in Embodiment 1 of this invention. It is a flowchart showing operation | movement of the frame transmission / reception control part for multiple fault detection shown in Embodiment 1 of this invention. It is a flowchart showing operation | movement of the shared link failure management part shown in Embodiment 1 of this invention. It is a flowchart showing operation | movement of the multiple failure detection part shown in Embodiment 1 of this invention. It is a figure which shows the operation | movement at the time of normal of the multi-ring network shown in Embodiment 1 of this invention. It is a figure which shows the path | route switching operation | movement of the multi-ring network shown in Embodiment 1 of this invention. It is a figure which shows the operation | movement at the time of failure occurrence of the multi-ring network shown in Embodiment 1 of this invention. It is a figure which shows the operation | movement at the time of failure occurrence of the multi-ring network shown in Embodiment 1 of this invention. It is a figure which shows the operation | movement at the time of failure occurrence of the multi-ring network shown in Embodiment 1 of this invention. It is a figure which shows the number of failures which each ring network shown in Embodiment 1 of this invention manages. It is a figure which shows the operation | movement at the time of failure occurrence of the multi-ring network shown in Embodiment 1 of this invention. It is a figure which shows the operation | movement at the time of failure occurrence of the multi-ring network shown in Embodiment 1 of this invention. It is a figure which shows the operation | movement at the time of failure occurrence of the multi-ring network shown in Embodiment 1 of this invention. It is a figure which shows the operation | movement at the time of failure occurrence of the multi-ring network shown in Embodiment 1 of this invention. It is a figure which shows the operation | movement at the time of failure occurrence of the multi-ring network shown in Embodiment 1 of this invention. It is a figure which shows the structure of the multi-ring network shown in Embodiment 1 of this invention. It is a figure which shows the structure of the multi-ring network shown in Embodiment 1 of this invention. It is a figure which shows the problem of the conventional multi-ring network.

Embodiment 1 FIG.
FIG. 1 shows a configuration diagram of a multi-ring network according to Embodiment 1 of the present invention. In FIG. 1, the multi-ring network is composed of two ring networks (hereinafter abbreviated as “ring” as appropriate), which are a ring network A and a ring network B, and each ring is assigned a ring ID. In the multi-ring network shown in FIG. 1, the ring network A is set in advance as a sub-ring that does not perform failure management of shared links, and the ring network B is set as a major ring that performs failure management of shared links. Ring ID = 1 is assigned to ring network A, and ring ID = 2 is assigned to ring network B.

  The ring network A has node devices 10a to 10c, and the ring network B has node devices 11a to 11c. The ring network A and the ring network B have node devices (hereinafter, appropriately referred to as ring connection nodes) 12a and 12b that are shared with each other, and are connected to each other via the ring connection nodes 12a and 12b. . That is, the ring network A and the ring network B are connected so as to share a link between the ring connection node 12a and the ring connection node 12b, and the link between the ring connection node 12a and the ring connection node 12b is connected. This is called a shared link. Although FIG. 1 shows a multi-ring network having eight node devices including two ring connection nodes, it goes without saying that the number of node devices and ring connection nodes is not limited to this. Further, FIG. 1 shows a structure in which two ring networks are connected, but the present invention can also be applied to a structure in which three or more ring ring networks are connected.

  Each node device has a plurality of ports, and a link is formed by connecting the ports to operate as a multi-ring network. In the multi-ring network shown in FIG. 1, the ring connection nodes 12a and 12b have three ports, and the node devices 10a to 10c and the node devices 11a to 11c have two ports.

  The node devices 10b and 11c operate as ERP RPL (Ring Protection Link) owner nodes, and the other node devices 10a, 10c, 11a, and 11b operate as non-RPL owner nodes of ERP. Here, it is assumed that the operation according to the ERP standard, which is a conventional technique, is performed.

  The ring networks A and B are operated in a state where one specific link in each ring network is logically disconnected so that a loop frame does not occur inside. Here, a link with an adjacent node device is logically disconnected by closing one port of the node device. Here, the link disconnection point is called a BP (Blocking Point), and the blocked port is called a BP-set port. One of the ports of the RPL owner (node devices 10b and 11c) is set to BP. In the ring network shown in FIG. 1, the node device 10c side port of the node device 10b and the node device 11c The port on the node device 11b side is set to BP (BP 14a and BP 14b). At the port set to BP, the control frame and the data frame are discarded without being transferred to the adjacent node device. On the other hand, transfer of control frames and data frames to adjacent node devices is permitted at ports where BP is not set.

  FIG. 2 is a block diagram showing the configuration of the ring connection node 12a. In FIG. 2, the ring connection node 12a includes a connection port 21a on the ring network A side (hereinafter referred to as A side port 21a), a connection port 21b on the ring network B side (hereinafter referred to as B side port 21b), and a shared link. -Side connection port 21c (hereinafter referred to as C-side port 21c), a transmission / reception control unit (port A transmission / reception control unit 22a, port B transmission / reception control unit 22b, port C transmission / reception control unit 22c) that manages frame transmission / reception at each port ), A ring A-ERP control unit 23a for protecting the ring network connected to the A side port 21a, a ring B-ERP control unit 23b for protecting the ring network connected to the B side port, and a frame transfer database. FDB (Forwarding DataBase) control unit 24 that controls network, shared link failure A multi-fault management unit 25 that manages harm and multi-faults and switches between major ring and sub-ring is provided. The configuration of the ring connection node 12b is the same as that of the ring connection node 12a, and the description thereof is omitted.

  FIG. 3 is a block diagram showing input / output of the port A transmission / reception control unit 22a. The port A transmission / reception control unit 22a is functionally divided into a reception processing unit and a transmission processing unit. In the reception processing unit, the frame transferred from the A-side port 21a or another control unit is identified, the frame is transferred to the transfer destination according to the frame identification result, and the address learning information related to the frame is sent to the FDB control unit 24. To notify. In addition, the FDB control unit 24 is instructed to search for an address for the arrived frame, and the frame is transferred to the port to be transmitted based on the search result of the destination address obtained from the FDB control unit. Note that when the BP setting instruction for the A-side port 21a is pointed from the ring A-ERP control unit 23a, the frame received from the A-side port 21a is discarded.

  In addition, as a result of identifying the received frame, if it is an R-APS frame or a CCM frame that is an adjacent monitoring frame, an ERP control unit (ring A-ERP control unit 23a or ring B-ERP control unit that performs protection control) Transfer the frame to 23b). As a result of identifying the received frame, if the received frame is a multiple failure detection frame, the frame is transferred to the multiple failure management unit 25. The validity of the received frame is confirmed, and if it is not valid (there is an error), the received frame is discarded.

  The transmission processing unit receives the R-APS frame transferred from the ERP control unit and the data frame transferred from the port B and C transmission / reception control units 22b and c, and receives a BP setting instruction from the ring A-ERP control unit 23a. If not, it is transmitted from the A side port 21a. Also, the multiple failure detection frame transferred from the multiple failure management unit 25 is transmitted from the A-side port 21a. The transmission processing unit periodically transmits a CCM frame for adjacency monitoring. The port B transmission / reception processing unit 22b also has the same function as the port A transmission / reception control unit 22a.

  FIG. 4 is a block diagram showing input / output of the port C transmission / reception control unit 22c. The port C transmission / reception control unit 22c is divided into a reception processing unit and a transmission processing unit. The reception processing unit identifies the arrived frame and notifies the FDB control unit 24 of address learning information. If there is no BP setting instruction from the ERP control unit, an address search is performed to the FDB control unit 24, and a frame is sent to the port to be transmitted based on the search result of the destination address obtained from the FDB control unit 24. Forward.

  As a result of identifying the arrival frame, the reception processing unit transfers the frame to the multiple failure management unit 25 in the case of an R-APS frame, a CCM frame, or a multiple failure detection frame. The reception processing unit confirms the validity of the received frame, and when it is not valid (there is an error), discards the received frame.

  The transmission processing unit transmits the R-APS frame transferred from the ERP control unit. When there is no BP setting instruction from the ERP control unit, the transmission processing unit transmits the data frame transferred from the port A and B transmission / reception control units 22a and 22b from the C-side port 21c. In addition, the multiple failure detection frame transferred from the multiple failure management unit is transmitted from port A. The transmission processing unit periodically transmits the CCM frame to the C-side port 21c.

  FIG. 9 is a block diagram showing input / output of the ring A-ERP control unit 23a. The ring A-ERP control unit 23a observes the CCM frame transferred from the port A transmission / reception control unit 22a, and detects the occurrence of a failure when it has not been received for a certain period of time. When a failure is detected, a BP setting instruction is issued to the port A transmission / reception control unit. When the multiple failure management unit 25 is notified of the occurrence of a failure in the link on the C-side port 21c side, it instructs the port C transmission / reception control unit 22c to set BP. Further, when a CCM frame is transferred from the port A transmission / reception controller 22a after detecting a failure in the A-side port 21a, failure recovery is detected.

  The ring A-ERP control unit 23a generates an R-APS frame when a failure is detected or a failure recovery is detected, and transfers the R-APS frame from the multiple failure management unit 25 to the transmission / reception control unit of the designated port. In addition, ERP control is performed from information of the R-APS frame transferred from the port transmission / reception control unit and the multiple failure management unit. Also, the received R-APS frame is transferred to the transmission / reception control unit of the port instructed by the multiple failure management unit 25.

  When the R-APS (NR / RB) frame is transferred from the port A transmission / reception control unit after the shared link failure recovery notification from the multiple failure management unit 25, the ring A-ERP control unit 23a sends an R to the multiple failure management unit. -APS (NR / RB) reception information is notified. The ring B-ERP control unit 23b has the same function as the ring A-ERP control unit 23a.

  The FDB control unit 24 creates a database for frame transfer from the address learning information from the transmission / reception control unit of each port. Further, the database is searched from the address search information of the transmission / reception control unit of each port, and the transfer destination port is designated. When there is an FDB flush instruction from the ERP control unit, FDB flush is performed.

  FIG. 6 shows input / output of the multiple failure management unit 25. In the multiple failure management unit, the major ring for managing the failure of the shared link is initially set to be either ring network A or ring network B. In the multi-ring network shown in FIG. 1, the ring network B is a major ring and the ring network A is a sub-ring. The ring ID of the ring network to be connected is set in the same manner.

  The multiple failure management unit 25 is divided into a multiple failure detection frame transmission / reception control unit 26, a shared link failure management unit 27, and a multiple failure detection unit 28. The operation of the multi-failure detection frame transmission / reception control unit 26 will be described with reference to the flowchart shown in FIG. The multi-failure detection frame transmission / reception control unit 26 generates a multi-failure detection frame to which a major ring ID (major ring ID) is added, and sets a port transmission control unit on the major ring side that is initially set (in FIG. 2). The port B transmission / reception control unit 22b) and the port C transmission / reception control unit 22c are periodically transferred (step S101). When multiple faults are detected, the data is transferred only to the port C transmission / reception control unit.

  When the multiple failure detection frame is transferred from the port transmission / reception control unit on the measuring side (steps S102 and S103), the transferred frame is identified, and the measuring ID is added to the frame (step S104). Yes), the multiple failure detection unit 28 is notified that the multiple failure detection frame has been received (step S105). If no majoring ID is added as a result of frame identification (No in step S104), the received frame is transferred to the port transmission / reception control unit (port A transmission / reception control unit 22a in FIG. 2) on the sub-ring side (step S104). S106).

  In addition, when a multiple failure detection frame to which a majoring ID is added is transferred from the sub-ring side (Yes in Step 107), the multiple failure detection frame transmission / reception control unit 26 discards the frame (Step S111). ). In addition, when a shared link failure has occurred (Yes in step 108), when a multi-failure detection frame without a measuring ID is transferred from the sub-ring side, port transmission / reception on the measuring side is performed. The VLAN setting or the like is changed and transferred to the control unit so as to go around the major ring (step S109). When no shared link failure has occurred (No in Step 108), when a multiple failure detection frame without a majoring ID is transferred from the sub-ring side, the port C transmission / reception control unit 22c The received multiple failure detection frame is transferred to (step S110).

  Next, the operation of the shared link failure management unit 27 will be described with reference to the flowchart shown in FIG. The shared link failure management unit 27 determines that a shared link failure has been detected when the port C transmission / reception control unit 22c has not transferred a multi-failure detection frame for a certain period of time (step S201), and notifies the multi-failure detection unit to that effect. Notification is made (step S202). When the multiple failure detection frame is transferred from the port C transmission / reception control unit 22c (step S203), the shared link failure recovery is detected and transferred to the ERP control unit on the measuring side (step S204).

  Note that a shared link failure and its recovery may be detected using an adjacent monitoring frame (CCM frame). In this case, if the CCM frame is not transferred from the port C transmission / reception control unit 22c for a predetermined time, the shared link failure management unit 27 detects a failure and notifies the ERP control unit on the measuring side. After the failure is detected, when the CCM frame is transferred from the port C transmission / reception control unit 22c, the failure recovery is detected and notified to the ERP control unit on the measuring side.

  Next, the multiple failure detection operation of the multiple failure detection unit 28 will be described with reference to the flowchart shown in FIG. The multi-failure detection unit 28 operates as a setting replacement unit that switches the setting between the major ring and the sub ring for each ring network. The multi-fault detection unit 28 transmits the R-APS frame transmission destination to the ERP control unit (ring A-ERP control unit 23a or ring B-ERP control unit 23b) from a predetermined setting state of major ring and sub ring. The port transmission / reception control unit is notified (step S301). When a shared link failure is detected (Yes in step S302), if there is no transfer of a multi-failure detection frame for a certain time from the port transmission / reception control unit on the measuring side (port B transmission / reception control unit 22b in FIG. 2), a multiple failure is detected. (Step S302). When the multiple failure detection unit 28 detects multiple failures, the multiple failure detection unit 28 switches the initialized major ring to the sub ring and the sub ring to the major ring (step S304). Thereby, the transfer destination ERP control unit of the R-APS frame transferred from the port C transmission / reception control unit and the ERP control unit that notifies the failure detected in the C-side port 21c are switched.

  The multi-fault detection unit 28 detects a multi-fault, and further detects recovery of the shared link fault, and then receives R-APS (NR / RB) reception information from the measuring-side ERP control unit (Yes in step S306). ) The majoring and subring that have been switched due to the occurrence of multiple failures are switched back to the default majoring and subring (step S307). The multiple failure detection function transfers the R-APS frame transferred from the C-side port 21c to the ERP control unit on the measuring side.

Next, the operation of the multi-ring network according to the present invention will be described.
First, an operation in a normal state (when no failure has occurred) will be described with reference to FIG. Here, the major ring that performs failure management of the shared link is preset as ring network B, and the sub-ring is preset as ring network A. When a data frame is generated in a node device that is a transmission source, the data frame is transferred to an adjacent node device. The node device that has received the data frame transfers the data frame to the adjacent node device on the opposite side when the data frame is not addressed to the own node device.

  Further, the ring connection nodes 12a and 12b periodically transmit a multi-failure detection frame from the ring B side port, which is a major ring, and the shared link side port. Rings A and B are configured with VLANs that circulate around the ring, and transmit to the major ring using the VLANs (usually for ERP multi-rings, an R-APS circuit that circulates around each ring. Since the VLAN is set, use that VLAN). Since blocking is always set at some port in the major ring (blocking point 14b), each node device receives a frame for detecting multiple failures from only one of the ports when it is normal. In addition, all node devices transmit a CCM frame for adjacency monitoring and perform adjacency monitoring.

  Next, a path switching operation when a failure occurs only in the shared link will be described with reference to FIG. As shown in FIG. 11, when a failure occurs in the shared link 13, the ring connection nodes 12a and 12b detect the failure due to the non-arrival of the adjacent monitoring frame (CCM frame) periodically transmitted from the adjacent node device. The failure detection port (here, the C-side port 21c) is blocked, and the C-side port 21c is set to BP. In the major ring, normal ERP protection operates, and the ring connection nodes 12a and 12b are adjacent node devices that receive R-APS (SF) frames from the port on the major ring side (here, the B side port 21b). Send to. The node device 11c, which is the RPL owner node in the ring network B that has received the R-APS (SF) frame, cancels the port block setting in accordance with the ERP standard. Even in this situation, the ring connection nodes 12a and 12b continue to transmit the multi-fault detection frame, and can receive the multi-fault detection frame that circulates in the ring network B after the port block of the node device 11c is released. It becomes. Therefore, when only a shared link failure occurs, multiple failures are not detected, and normal ERP operation is performed.

  The multiple failure detection function using the multiple failure detection frame has three or more rings configured by ring connection nodes 33a to 33d and node devices 30a to 30c, 31a to 31b, and 32a to 32c as shown in FIG. The present invention can also be applied to a multi-ring configuration to which a network is connected, and it is possible to detect multiple faults in the major ring. In FIG. 9, when a ring that performs failure management of a shared link between ring connection nodes 33a-33b is set as ring network B and a ring that manages failure of a shared link between ring connection nodes 33c-33d is set as ring C, a plurality of Even when a failure occurs in the shared link, the multiple failure detection frame for ring B transmitted by the node devices 33a and 33b passes through the ring network C, thereby causing multiple failures in the failure management area (in the shared link and in the major ring). Failure) can be detected.

  13 to 20 show a path switching operation when a multiple failure including a shared link failure occurs in the major ring. As shown in FIG. 13, it is assumed that after a failure occurs in the shared link 13, a failure occurs between the node device 11a and the node device 11b in the ring B, which is a major ring. When such a multiple failure occurs, the node devices 11a and 11b and the ring connection nodes 12a and 12b detect the failure due to the non-arrival of the adjacent monitoring frame transmitted periodically, and set the port on which the failure is detected to the BP. Set. Even after the shared link failure is detected as described above, the ring connection nodes 12a and 12b continue to transmit the multiple failure detection frame in the ring B, but the ring connection nodes 12a and 12b are connected between the node device 11a and the node device 11b. Due to this failure, the multiple failure detection frames cannot be received from each other, and the ring connection nodes 12a and 12b detect the occurrence of multiple failures when the multiple failure detection frame has not arrived (the multiple failure detection frame is not received for a certain period of time).

  FIG. 14 shows the operation after multiple failure detection. The ring connection nodes 12a and 12b switch between the major ring and the sub-ring by detecting multiple failures (shared link failure information is transferred from the ring B ERP control unit (B-ERP control unit 23b) to the ring network A ERP control unit. (Switch to A-ERP control unit 23a)). As a result, transmission of the R-APS (SF) frame due to the shared link failure was transmitted to the ring B side port before the multiple failure detection, but after the multiple failure detection, it was transmitted to the ring A side port. Normal ERP protection is performed on the ring A side. That is, in the ring network A, the node device 10b, which is the RPL owner node, cancels the BP setting of the port on the node device 10c side by receiving the R-APS (SF) frame from the ring connection nodes 12a and 12b. By releasing the port blockage in the node device 10b, communication is possible between all the nodes on the ring network B side, and failure bypass (communication path switching) is completed. FIG. 15 shows the number of failures managed by the ERP in the ring networks A and B before and after switching between the major ring and the sub-ring. Before the switching, two failures occur only in the ring B, but after the switching, one failure is managed for each of the ring A and the ring B.

  FIG. 16 and FIG. 17 show the operation when the failure is recovered. As shown in FIG. 16, the ring connection nodes 12a and 12b that have detected the multiple failure stop the transmission of the multiple failure detection frame that was transmitted to the ring B that is the major ring, and the multiple failure only on the shared link side. Continue to send detection frames. When the shared link failure is recovered, R-APS (NR) is transmitted from the ring connection nodes 12a and 12b into the ring A as shown in FIG.

  As shown in FIG. 18, when receiving the R-APS (NR) from the ring connection nodes 12a and 12b, the node device 10b, which is the RPL owner node of the ring A, sets the port to be blocked, as shown in FIG. APS (NR / RB) is transmitted. The ring connection nodes 12a and 12b that have received the R-APS (NR / RB) frame from the node device 10b cancel the BP setting on the shared link side as shown in FIG. Also, the majoring and subring switched at the time of detecting a multi-fault are switched back to the initial settings by receiving this R-APS (NR / RB). After switching back, as in the normal state, a multiple failure detection frame is transmitted into ring B, which is a major ring, as shown in FIG. 20, and multiple failure is detected.

  Since the multi-ring network according to the embodiment of the present invention has the above-described configuration, the multi-ring network can appropriately switch the path even when a shared link and a multi-failure in the majoring network occur. And it becomes possible to carry out a detour.

  Note that the present invention can also be applied to a multi-ring network in which three or more ring networks are connected. An example of a multi-ring network in which three ring networks are connected is shown in FIG. In the multi-ring network as shown in FIG. 21, the ring networks A and B and the ring networks B and C are connected so as to form a shared link. The ring networks A to C are respectively node devices 30a to 30c and nodes. Devices 31a and 31b and node devices 32a to 32c are provided, and ring connection nodes 33a to 33d are provided at both ends of each shared link. Major ring and sub ring are set so that failure management of multiple shared links in the same ring is not performed. That is, ring B performs failure management of shared link 33a (between ring A and ring B, ring A side is set as a sub-ring and ring B side is set as a major ring), and ring C is shared link 34b. Failure management is performed (the ring B side is set as a sub-ring between the ring B and the ring C, and the ring C side is a major ring). By setting in this way, it is possible to bypass the failure even when multiple failures occur in the major ring. Note that the normal operation and the path switching operation when a failure occurs are the same as those described above.

  Further, the present invention can be applied even when another node device is included in the shared link. An example of a multi-ring network including node devices in the shared link is shown in FIG. In the multi-ring network shown in FIG. 22, the ring network A and the ring network B are connected so as to form shared links 44a and 44b, and a node device 42 is provided on the shared link. The normal operation and the path switching operation at the time of occurrence of a failure are the same as those described above. For example, when a failure occurs in one of the shared links 44a and 44b, the node device 42 in the shared link generates a failure. An operation such as notifying that a failure has occurred in the shared link is performed to the ring connection node connected to the port opposite to the port that detected the error. This makes it possible to bypass the failure even when a multiple failure including the shared link occurs.

10a-c, 11a-c node device, 12a, b node device (ring connection node), 13 shared link, 14a, b blocking point, 21a-c connection port, 22a-c transmission / reception control unit, 23a, b ERP control unit , 24 FDB control unit, 25 multiple failure management unit, 26 multiple failure detection frame transmission / reception control unit, 27 shared link failure management unit, 28 multiple failure detection unit, 30a-c, 31a-c, 32a-c node device, 33a -D Node device (ring connection node), 34a, b shared link, 40a-e, 41a-d, 42 node device, 43a, b Node device (ring connection node), 44a, b shared link

Claims (8)

A plurality of ring networks including a plurality of node devices and forming a link between adjacent node devices are connected to each other so as to form a shared link having ring connection nodes at both ends, and the plurality of ring networks A specific link among the links included in the network is set to be logically disconnected, and the specific ring network among the plurality of ring networks is set to the own ring network based on the detection result of the failure in the shared link. A ring connection node applicable to a multi-ring network preset to a major ring that releases a logical disconnection of included links,
A shared link failure detection unit for detecting a failure of a shared link included in the ring network set in the major ring;
A majoring fault detection unit that is included in the ring network configured for the majoring and detects a fault of a link excluding the shared link;
Based on the failure detection result by the shared link failure detection unit and the majoring failure detection unit, the setting is made to set the other ring network including the shared link in which the failure is detected and not set to the majoring as the majoring. A replacement department;
A ring connection node characterized by comprising:   The majoring fault detection unit transmits a multi-fault detection frame to a node device in a ring network set to the major ring, the fault in the shared link is detected by the shared link fault detection unit, and The ring connection node according to claim 1, wherein a failure is detected when a frame for detecting multiple failures from another ring connection node is not received for a predetermined time. A ring ID is assigned to each of the plurality of ring networks,
The multi-fault detection unit transmits the multi-fault detection frame including a ring ID related to the ring network set to the major ring to a node device in the ring network set to the major ring. The ring connection node according to claim 2. The multi-ring network is connected so that two ring networks form the shared link, one being the major ring and the other being a specific link in the own ring network regardless of detection of a failure in the shared link. Set to a sub-ring that continues to be logically disconnected,
The setting replacement unit replaces the setting of the major ring and the sub ring;
The ring connection node according to claim 1, wherein the ring connection node is a ring connection node. A recovery detector for detecting recovery of a failure in the shared link;
The setting replacement unit, when the recovery detection of the shared link is detected by the recovery detection unit, to reset the ring network previously set to the major ring to the major ring,
The ring connection node according to claim 1, wherein the ring connection node is a ring connection node. A plurality of ring networks including a plurality of node devices and forming a link between adjacent node devices are connected to each other so as to form a shared link having ring connection nodes at both ends, and the plurality of ring networks A specific link among the links included in the network is set to be logically disconnected, and the specific ring network among the plurality of ring networks is configured to perform logical analysis of the link based on the detection result of the failure in the shared link. A multi-ring network configured as a major ring to release a general disconnection,
A shared link failure detection unit for detecting a failure of a shared link included in the ring network set in the major ring;
A majoring fault detection unit that is included in the ring network configured for the majoring and detects a fault of a link excluding the shared link;
Based on the failure detection result by the shared link failure detection unit and the majoring failure detection unit, the setting is made to set the other ring network including the shared link in which the failure is detected and not set to the majoring as the majoring. A replacement department;
A link disconnection release unit for canceling a logical disconnection of a preset link of the ring network set as a major ring by the setting replacement unit;
A multi-ring network characterized by comprising:   The multi-ring network according to claim 6, wherein the node device logically disconnects a link with an adjacent node device connected to the blocked port by blocking the port of the node device of the node device. . A plurality of ring devices including a plurality of node devices and forming a link between adjacent node devices are connected to each other to form a shared link having ring connection nodes at both ends. A specific link included in the ring network is set to be logically disconnected, and among the plurality of ring networks, the specific ring network is logically disconnected based on the detection result of the failure in the shared link. A path switching method applicable to a multi-ring network set as a major ring that cancels
A shared link failure detection step of detecting a failure of a ring network set in the major ring;
A majoring fault detection step for detecting a fault of a link included in the ring network configured for the majoring and excluding the shared link;
Setting to set other ring networks including the shared link in which the failure is detected and not set to the major ring as the major ring based on the failure detection result by the shared link failure detection step and the major ring failure detection step. A replacement step;
A link disconnection releasing step for canceling a logical disconnection of a preset link of the ring network set in the major ring in the setting replacement step;
A path switching method characterized by comprising:

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