Non-interrupt redundant switching device, non-interrupt redundant switching method, non-interrupt redundant switching system, and program

Abstract

An uninterrupted redundancy switching device (1) according to the present disclosure which is equipped with an identifier assignment unit (12) for assigning a main signal identifier to a main signal frame, an uninterrupted processing unit (13) for duplicating the main signal frame to which the main signal identifier is assigned, and generating a first main frame in which an uninterrupted processing header is assigned to the main signal frame which was the duplication source, and a second main frame in which an uninterrupted processing header is assigned to the duplicated main signal frame, a first transport (16) for transmitting the first main frame, a second transport (17) for transmitting the second main frame, and an identifier assignment deletion unit (15) for generating a monitoring frame, wherein only one transport among the first transport (16) and the second transport (17) transmits the monitoring frame.

Description

Technical Field

[0001] The present disclosure relates to a non-interruptible redundancy switching device, a non-interruptible redundancy switching method, a non-interruptible redundancy switching system, and a program.

Background Art

[0002] By two non-interruptible redundancy switching devices (non-interruptible devices) executing non-interruptible redundancy switching using the Parallel Redundancy Protocol (PRP) via two communication lines, even if a frame loss occurs in one communication line, the frame loss can be compensated for by the frames transmitted via the other communication line (see Non-Patent Document 1 and Non-Patent Document 2).

[0003] However, for example, as shown in FIG. 10A, when a monitoring device 5 operated by a communication carrier or the like remotely monitors non-interruptible devices 9A and 9B respectively connected to user devices UA and UB, the non-interruptible devices 9A and 9B transmit and receive main signal frames via a communication line NW90 (indicated by a dashed-dotted line in FIG. 10A), and outband monitoring may be performed by transmitting and receiving monitoring signal frames with the monitoring device 5 via a communication line NW91 different from the communication line NW90 (indicated by a broken line in FIG. 10A).

[0004] Also, as shown in FIG. 10B, it is also conceivable to transmit and receive monitoring signal frames from the monitoring ports CP of the non-interruptible devices 9A and 9B via a communication line NW92 connecting the access ports AP of the non-interruptible devices 9A and 9B (indicated by a broken line in FIG. 10B). In this configuration, the non-interruptible devices 9A and 9B and the monitoring device 5 transmit and receive the monitoring signal frames via the communication line NW90 (indicated by a broken line in FIG. 10B), and inband monitoring may also be performed by the non-interruptible devices 9A and 9B transmitting and receiving main signal frames to each other (indicated by a dashed-dotted line in FIG. 10B). In the execution of inband monitoring, it becomes unnecessary to provide the communication line NW91 in the above-described outband monitoring.

[0005] In in-band monitoring, as shown in FIG. 11, in the hitless redundancy switching system 900, when transmitting the monitoring signal frame Fc, the hitless device 9A duplicates the monitoring signal frame Fc in the same manner as the main signal frame Fm, and performs a hitless redundancy switching process of attaching a hitless processing header HD (for example, a sequence number) to each of the original monitoring signal frame Fc and the duplicated monitoring signal frame Fc. Then, the hitless device 9A transmits two monitoring frames Fcs each with a monitoring signal identifier IDc and a hitless processing header HD attached to the monitoring signal frame Fc to the monitoring device 5 via two communication lines. At this time, the hitless device 9C further provided between the relay switch 3 and the monitoring network switch 4 selects one monitoring frame Fcs from the two monitoring frames Fcs transmitted via the two communication lines by the hitless redundancy switching process. Then, the hitless device 9C deletes the hitless processing header HD from the monitoring frame Fcs.

Prior Art Documents

Non-Patent Documents

[0006]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in in-band monitoring as shown in FIG. 11, as described above, in order for the monitoring device to monitor the non-break device 9A, the non-break redundant switching system 900 has to further include the non-break device 9C and thus has a complicated configuration.

[0008] Also, when communicating using PRP among the three non-break redundant switching devices 9A, 9B, and 9C in this way, for example, since the non-break redundant switching device 9C has to manage the non-break processing header HD for each of the monitoring frames Fcs transmitted from the non-break redundant switching devices 9A and 9B, the configuration has to be complicated.

[0009] In view of such circumstances, an object of the present disclosure is to provide a non-break redundant switching device, a non-break redundant switching method, a non-break redundant switching system, and a program that can be remotely monitored with a simple configuration. Means for Solving the Problems

[0010] To solve the above problems, the seamless redundant switching device according to the present disclosure is a seamless redundant switching device that communicates with another seamless redundant switching device using seamless redundant switching processing via a first communication line and a second communication line, and includes an identifier adding unit that adds a main signal identifier indicating that it is a main signal frame to a main signal frame received from a user device, a first main frame that duplicates the main signal frame with the main signal identifier added thereto and adds a seamless processing header indicating the order in which the main signal frame is transmitted to the main signal frame with the main signal identifier added thereto as the replication source, and a second main frame that adds a seamless processing header indicating the order in which the main signal frame is transmitted to the duplicated main signal frame with the main signal identifier added thereto, a first transport that transmits the first main frame to a first relay switch via the first communication line, a second transport that transmits the second main frame to a second relay switch different from the first relay switch via the second communication line, a monitoring function unit that generates a monitoring signal frame, and an identifier adding / removing unit that generates a monitoring frame with a monitoring signal identifier added thereto for identifying that it is a monitoring signal frame, and only one of the first transport and the second transport transmits the monitoring frame via the corresponding first communication line or the second communication line.

[0011] Also, to solve the above problems, the seamless redundancy switching method according to the present disclosure is a seamless redundancy switching method executed by a seamless redundancy switching device that communicates with another seamless redundancy switching device using seamless redundancy switching processing via a first communication line and a second communication line. The method includes: a step of attaching a main signal identifier indicating that it is a main signal frame to a main signal frame received from a user device; a step of duplicating the main signal frame to which the main signal identifier is attached, and attaching a seamless processing header indicating the order in which the main signal frame is transmitted to the main signal frame to which the main signal identifier is attached at the replication source, to generate a first main frame, and attaching a seamless processing header indicating the order in which the main signal frame is transmitted to the duplicated main signal frame to which the main signal identifier is attached, to generate a second main frame; a step of transmitting the first main frame to a first relay switch via the first communication line by a first transport; a step of transmitting the second main frame to a second relay switch different from the first relay switch via the second communication line by a second transport different from the first transport; a step of generating a monitoring signal frame; a step of generating a monitoring frame by attaching a monitoring signal identifier for identifying that it is a monitoring signal frame to the monitoring signal frame; and a step of transmitting the monitoring frame via the corresponding first communication line or the second communication line by only one of the first transport and the second transport.

[0012] In order to solve the above problems, the non-stop redundant switching system according to the present disclosure includes, via a first communication line and a second communication line, another non-stop redundant switching device, two non-stop redundant switching devices that communicate with each other using non-stop redundant switching processing, a first relay switch, a second relay switch, and a monitoring device. In the non-stop redundant switching system, each of the two non-stop redundant switching devices is a non-stop redundant switching device that communicates with another non-stop redundant switching device using non-stop redundant switching processing via the first communication line and the second communication line. The non-stop redundant switching device includes an identifier adding unit that adds a main signal identifier indicating that the received main signal frame from the user device is a main signal frame, a non-stop processing unit that duplicates the main signal frame with the main signal identifier added thereto, and adds a non-stop processing header indicating the order in which the main signal frame is transmitted to the original main signal frame with the main signal identifier added thereto to generate a first main frame, and adds a non-stop processing header indicating the order in which the main signal frame is transmitted to the duplicated main signal frame with the main signal identifier added thereto to generate a second main frame, a first transport that transmits the first main frame to a first relay switch via the first communication line, a second transport that transmits the second main frame to a second relay switch different from the first relay switch via the second communication line, a monitoring function unit that generates a monitoring signal frame, and an identifier adding / removing unit that generates a monitoring frame by adding a monitoring signal identifier for identifying that the monitoring signal frame is a monitoring signal frame. Only one of the first transport and the second transport transmits the monitoring frame via the corresponding first communication line or the second communication line.

[0013] In order to solve the above problems, the program according to the present disclosure causes a computer to operate as the above-described non-stop redundant switching device.

Advantages of the Invention

[0014] According to the non-stop redundant switching device, non-stop redundant switching method, non-stop redundant switching system, and program according to the present disclosure, remote monitoring can be performed with a simple configuration.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10A

Figure 10B

Figure 11

Modes for Carrying Out the Invention

[0016] <<First Embodiment>> Referring to FIG. 1, the overall configuration of the first embodiment will be described. FIG. 1 is a schematic diagram showing an example of a non-stop redundant switching system 100 according to the first embodiment.

[0017] The non-stop redundant switching system 100 includes a user device UA, a user device UB, a non-stop redundant switching device 1A, a non-stop redundant switching device 1B, a first relay switch 3A, a second relay switch 3B, a monitoring network switch 4, and a monitoring device 5. Note that the non-stop redundant switching system 100 may not include the monitoring network switch 4 in a configuration where the monitoring device 5 does not communicate with one or more other non-stop redundant switching devices different from the non-stop redundant switching device 1A and the non-stop redundant switching device 1B.

[0018] The user device UA and the non-stop redundant switching device 1A can directly communicate with each other. The user device UB and the non-stop redundant switching device 1B can directly communicate with each other. The non-stop redundant switching device 1A and the non-stop redundant switching device 1B communicate with each other through being relayed by the first relay switch 3A via the first communication line NW1. Also, the non-stop redundant switching device 1A and the non-stop redundant switching device 1B communicate with each other through being relayed by a second relay switch 3B different from the first relay switch 3A via a second communication line NW2 different from the first communication line NW1. Further, each of the non-stop redundant switching device 1A and the non-stop redundant switching device 1B and the monitoring device 5 communicate with each other through being relayed by the first relay switch 3A or the second relay switch 3B and the monitoring network switch 4.

[0019] Hereinafter, the non-stop redundant switching device 1A and the non-stop redundant switching device 1B may be simply referred to as the "non-stop device 1A" and the "non-stop device 1B", respectively. Each of the non-stop redundant switching device 1A and the non-stop redundant switching device 1B may be simply referred to as the "non-stop device 1". Also, each of the user device UA and the user device UB may be simply referred to as the "user device U". Further, each of the first relay switch 3A and the second relay switch 3B may be simply referred to as the "relay switch 3".

[0020] <User device> The user device UA and the user device UB are each composed of a computer including a controller, a memory, and a communication interface. The controller may be composed of dedicated hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array), or may be composed of a processor, or may be composed of both. The memory may be composed of registers in hardware such as an ASIC or an FPGA, or may be composed of an HDD (Hard Disk Drive), an SSD (Solid State Drive), an EEPROM (Electrically Erasable Programmable Read-Only Memory), a ROM (Read-Only Memory), a RAM (Random Access Memory), etc. For the communication interface, for example, standards such as Ethernet (registered trademark), FDDI (Fiber Distributed Data Interface), Wi-Fi (registered trademark), etc. may be used.

[0021] The user device UA and the user device UB each transmit the main signal frame Fm to the uninterruptible device 1A and the uninterruptible device 1B, respectively. Also, the user device UA and the user device UB each receive the main signal frame Fm from the uninterruptible device 1A and the uninterruptible device 1B, respectively. FIG. 1 shows an example in which the user device UA transmits the main signal frame Fm to the uninterruptible device 1A. Note that the present invention is not limited to this, and the user device UB may transmit the main signal frame Fm to the uninterruptible device 1B.

[0022] <Configuration of uninterruptible device> As shown in FIG. 2, the non-break device 1A includes an access port 11, an identifier adding unit 12, a non-break redundancy switching processing unit (non-break processing unit) 13, a monitoring function unit 14, an identifier adding / removing unit 15, a first transport (first communication interface) 16, a second transport (second communication interface) 17, a signal distribution unit 18, and an identifier removing unit 19. The access port 11, the first transport 16, and the second transport 17 are constituted by communication interfaces. For the communication interface, standards such as Ethernet (registered trademark), FDDI (Fiber Distributed Data Interface), Wi-Fi (registered trademark), etc. may be used. The identifier adding unit 12, the non-break processing unit 13, the monitoring function unit 14, the identifier adding / removing unit 15, the signal distribution unit 18, and the identifier removing unit 19 are constituted by controllers. Also, each functional unit may be configured integrally with other functional units or may be configured separately.

[0023] The access port 11 transmits and receives the main signal frame Fm to and from the user device U via a communication line. In the example shown in FIG. 1, the access port 11 included in the non-break device 1A transmits and receives the main signal frame Fm to and from the user device UA. Also, the access port 11 included in the non-break device 1B transmits and receives the main signal frame Fm to and from the user device UB.

[0024] The identifier adding unit 12 shown in FIG. 2 adds a main signal identifier IDm to the main signal frame Fm received from the user device U via the access port 11. The main signal identifier IDm is an identifier indicating that the frame to which the main signal identifier IDm is added is the main signal frame Fm.

[0025] The non-break processing unit 13 has a duplicator 131 and a selector 132.

[0026] The duplicator 131 duplicates the main signal frame Fm to which the main signal identifier IDm is assigned. Further, the duplicator 131 generates a first main frame Fms1 in which the header HD for seamless processing is added to the main signal frame Fm with the main signal identifier IDm as the original for duplication, and a second main frame Fms2 in which the header HD for seamless processing is added to the duplicated main signal frame Fm to which the main signal identifier IDm is assigned. The header HD for seamless processing is information added to the main signal frame Fm and is information for recognizing that the main signal frame Fm has been lost due to disconnection of a communication line or the like. The header HD for seamless processing is, for example, information indicating the order in which the main signal frame Fm to which the header HD for seamless processing is added is transmitted, and as an example, it can be a sequence number.

[0027] The selector 132 selects a main frame for transmission to the user device U from the main frames received by the first transport 16 and the second transport 17 respectively, based on the header HD for seamless processing. The selector 132 can select the main frame according to any seamless redundancy switching process.

[0028] The monitoring function unit 14 generates a monitoring signal frame Fc. The monitoring signal frame Fc is a frame that is transmitted and received between the seamless device 1 and the monitoring device 5 and is used for the monitoring process by the monitoring device 5 and the monitoring function unit 14. The monitoring signal frame Fc can be a frame corresponding to the monitoring process by the monitoring device 5 and the monitoring function unit 14.

[0029] The identifier adding / removing unit 15 generates a monitoring frame Fcs by adding a monitoring signal identifier IDc indicating that it is a monitoring signal frame to the monitoring signal frame Fc. The monitoring signal identifier IDc is an identifier indicating that the frame to which the monitoring signal identifier IDc is added is a monitoring signal frame. The monitoring signal identifier IDc can be, for example, an identifier of a VLAN (Virtual Local Area Network) defined by IEEE (Institute of Electrical and Electronics Engineers) 802.1Q.

[0030] Also, the monitoring frame Fcs generated by the identifier adding / removing unit 15 is transmitted by the first transport. That is, the identifier adding / removing unit 15 causes the first transport 16 to transmit the monitoring frame Fcs. For example, the identifier adding / removing unit 15 may control the signal distribution unit 18 to cause the first transport 16 to transmit the monitoring frame Fcs.

[0031] The first transport 16 transmits the first main frame Fms to the first relay switch 3A via the first communication line NW1. Also, the first transport 16 receives the main frame transmitted by the user device UB from the first relay switch 3A via the first communication line NW1.

[0032] The second transport 17 transmits the second main frame Fms2 to a second relay switch 3B different from the first relay switch 3A via the second communication line NW2. Also, the second transport 17 receives the main frame transmitted by the user device UB from the second relay switch 3B via the second communication line NW2.

[0033] Also, only one of the first transport 16 and the second transport 17 transmits the monitoring frame Fcs to the relay switch 3. In the first embodiment, the first transport 16 transmits the monitoring frame Fcs to the first relay switch 3A via the first communication line NW1. Also, in the first embodiment, the first transport 16 receives, via the first communication line NW1, the monitoring frame Fcs transmitted by the monitoring device 5 from the first relay switch 3A.

[0034] Based on whether the identifier attached to the frame received by the transport (the first transport 16 in the first embodiment) that transmits the monitoring frame Fcs among the first transport 16 and the second transport 17 is the main signal identifier IDm or the monitoring signal identifier IDc, the signal distribution unit 18 determines whether the frame is the main frame Fms or the monitoring frame Fcs. The signal distribution unit 18 outputs the main frame Fms to the seamless processing unit 13 and outputs the monitoring frame Fcs to the monitoring function unit 14.

[0035] Specifically, the signal distribution unit 18 determines whether the identifier included in the frame received by the first transport 16 is the main signal identifier IDm or the monitoring signal identifier IDs. When the signal distribution unit 18 determines that the identifier is the main signal identifier IDm, it determines that the frame is the main frame. Also, when the signal distribution unit 18 determines that the identifier is the monitoring signal identifier IDs, it determines that the frame is the monitoring frame Fcs.

[0036] Also, when the signal distribution unit 18 determines that the frame is the main frame, it outputs the main frame to the selector 132 of the seamless processing unit 13. When the signal distribution unit 18 determines that the frame is the monitoring frame Fcs, it outputs the monitoring frame Fcs to the identifier adding / removing unit 15.

[0037] The identifier deletion unit 19 further deletes the main signal identifier IDm from the main frame Fms that is selected by the selector 132 and from which the header HD for seamless processing has been deleted. As a result, the above-described access port 11 can transmit the main signal frame Fm, from which the header HD for seamless processing and the main signal identifier IDm have been deleted from the main frame Fms, to the user device U.

[0038] <Configuration of the Relay Switch> The relay switch 3 receives the main frame transmitted by the seamless device 1 via the communication line. In the example shown in FIG. 1, the first relay switch 3A receives the main frame Fms1 transmitted from the first transport 16 of the seamless device 1A via the first communication line NW1. Also, the second relay switch 3B receives the main frame Fms2 transmitted from the second transport 17 of the seamless device 1A via the second communication line NW2. Similarly, the first relay switch 3A receives the main frame Fms1 transmitted from the first transport 16 of the seamless device 1B via the first communication line NW1. Also, the second relay switch 3B receives the main frame Fms2 transmitted from the second transport 17 of the seamless device 1B via the first communication line NW1.

[0039] The relay switch 3 also receives the monitoring frame Fcs transmitted by the seamless device 1 via the communication line. In the example shown in FIG. 1, the first relay switch 3A receives the monitoring frame Fcs transmitted from the first transport 16 of the seamless device 1A via the first communication line NW1. Similarly, the first relay switch 3A receives the monitoring frame Fcs transmitted from the first transport 16 of the seamless device 1B via the first communication line NW1.

[0040] The relay switch 3 transmits the main frame Fms received from one non-interruptible device 1 to the other non-interruptible device 1, and transmits the monitoring frame Fcs received from the non-interruptible device 1 to the monitoring device 5 via the monitoring network switch 4. In a configuration where the non-interruptible redundancy switching system 100 does not include the monitoring network switch 4, the relay switch 3 directly transmits the monitoring frame Fcs received from the non-interruptible device 1 to the monitoring device 5.

[0041] Specifically, when the relay switch 3 receives a frame from the first non-interruptible device 1A, it determines whether the frame is the main frame Fms or the monitoring frame Fcs. For example, the relay switch 3 may determine whether the identifier included in the frame is the main signal identifier IDm or the monitoring signal identifier IDs. In such a configuration, when the relay switch 3 determines that the identifier is the main signal identifier IDm, it determines that the frame is the main frame Fms and transmits the main frame Fms to the second non-interruptible device 1B. Also, when the relay switch 3 determines that the identifier is the monitoring signal identifier IDc, it determines that the frame is the monitoring frame Fcs and transmits the monitoring frame Fcs to the monitoring network switch 4.

[0042] Similarly, when the relay switch 3 receives a frame from the second non-interruptible device 1B, it determines whether the frame is the main frame Fms or the monitoring frame Fcs. For example, the relay switch 3 may determine whether the identifier included in the frame is the main signal identifier IDm or the monitoring signal identifier IDs. In such a configuration, when the relay switch 3 determines that the identifier is the main signal identifier IDm, it determines that the frame is the main frame Fms and transmits the main frame Fms to the first non-interruptible device 1A. Also, when the relay switch 3 determines that the identifier is the monitoring signal identifier IDc, it determines that the frame is the monitoring frame Fcs and transmits the monitoring frame Fcs to the monitoring network switch 4.

[0043] Also, the relay switch 3 transmits the monitoring signal frame Fc, which is transmitted from the monitoring device 5 and relayed by the monitoring network switch 4, to the non-breakover device 1. In a configuration where the non-breakover redundancy switching system 100 does not include the monitoring network switch 4, the relay switch 3 directly receives the monitoring signal frame Fc transmitted from the monitoring device 5. Then, the relay switch 3 transmits the monitoring frame Fcs to the non-breakover device 1 corresponding to the destination included in the monitoring signal frame Fc. For example, when the destination included in the monitoring signal frame Fc is the user device UA, the relay switch 3 transmits the monitoring frame Fcs to the non-breakover device 1A. Also, when the destination indicated by the monitoring signal frame Fc is the user device UB, the relay switch 3 transmits the monitoring frame Fcs to the non-breakover device 1B.

[0044] <Configuration of the monitoring network switch> The monitoring network switch 4 transmits the monitoring signal frame Fc to the relay switch 3 that can transmit information to the non-breakover device 1 corresponding to the user device U, which is the destination indicated by the monitoring signal frame Fc included in the monitoring frame Fcs transmitted from the monitoring device 5.

[0045] <Configuration of the monitoring device> The monitoring device 5 is composed of a computer including a memory, a controller, and a communication interface. The monitoring device 5 receives the monitoring frame Fcs transmitted from the non-breakover device 1A via the first communication line NW1. The monitoring device 5 can execute known monitoring processing using the monitoring signal frame Fc included in the monitoring frame Fcs. Also, the monitoring device 5 transmits the monitoring frame Fcs to the non-breakover device 1.

[0046] In the first embodiment, the first transport 16 transmits the monitoring frame Fcs via the first communication line NW1. However, this is not the only case. The second transport 17 may transmit the monitoring frame Fcs via the second communication line NW2. In such a configuration, instead of the first transport 16, the second transport 17 receives the monitoring frame Fcs transmitted by the monitoring device 5 from the second relay switch 3B via the second communication line NW2. Further, the signal distribution unit 18 determines whether the frame received by the second transport 17 rather than the first transport 16 is the main frame or the monitoring frame Fcs.

[0047] <Operation of the non-interruptible device> Next, the operation of the non-interruptible device 1 according to the first embodiment will be described with reference to FIGS. 3A, 3B, and 4. FIG. 3A is a flowchart showing an example of the operation for transmitting the main frame in the non-interruptible device 1 according to the first embodiment. FIG. 3B is a flowchart showing an example of the operation for transmitting the monitoring frame Fcs in the non-interruptible device 1 according to the first embodiment. FIG. 4 is a flowchart showing an example of the operation for processing the received frame in the non-interruptible device 1 according to the first embodiment. The operation of the non-interruptible device 1 described with reference to FIGS. 3A, 3B, and 4 corresponds to the non-interruptible redundancy switching method executed by the non-interruptible device 1 according to the first embodiment.

[0048] As shown in FIG. 3A, in step S11, the access port 11 receives the main signal frame Fm transmitted from the user device U.

[0049] In step S12, the identifier addition / removal unit 15 adds a main signal identifier IDm indicating that it is the main signal frame Fm to the main signal frame Fm received from the user device U.

[0050] In step S13, the non-interruptible processing unit 13 copies the main signal frame Fm to which the main signal identifier IDm is added.

[0051] In step S14, the seamless processing unit 13 generates a first main frame Fms1 in which a seamless processing header HD is added to the main signal frame Fm with the main signal identifier IDm of the replication source, and a second main frame Fms2 in which a seamless processing header HD is added to the replicated main signal frame Fm with the main signal identifier IDm.

[0052] In step S15, the first main frame Fms1 is transmitted to the first relay switch 3A via the first communication line NW1.

[0053] In step S16, the second main frame Fms2 is transmitted to a second relay switch 3B different from the first relay switch 3A via the second communication line NW2.

[0054] As shown in FIG. 3B, in step S21, the monitoring function unit 14 generates a monitoring signal frame Fc.

[0055] In step S22, the identifier adding / removing unit 15 generates a monitoring frame Fcs in which a monitoring signal identifier IDc for identifying that it is the monitoring signal frame Fc is added to the monitoring signal frame Fc.

[0056] In step S23, only one of the first transport 16 and the second transport 17 transmits the monitoring frame Fcs to the relay switch 3. In the first embodiment, for example, only the first transport 16 transmits the monitoring frame Fcs to the relay switch 3.

[0057] As shown in FIG. 4, in step S31, the first transport 16 and the second transport 17 receive frames.

[0058] In step S32, based on whether the identifier attached to the frame received by the transport that transmits the monitoring frame Fcs among the first transport 16 and the second transport 17 is the main signal identifier IDm or the monitoring signal identifier IDc, the signal distribution unit 18 determines whether the frame is the main frame Fms or the monitoring frame Fcs. That is, in the first embodiment, the signal distribution unit 18 determines whether the frame received by the first transport 16 is the main frame Fms.

[0059] If it is determined in step S32 that the frame is the main frame Fms, then in step S33, based on the seamless processing header HD, the seamless processing unit 13 selects the main frame to be transmitted to the user device U from the main frames Fms received by the first transport 16 and the second transport 17 respectively. At this time, the seamless processing unit 13 deletes the seamless processing header HD from the selected main frame.

[0060] In step S34, the identifier deletion unit 19 deletes the main signal identifier IDm from the main frame Fms selected in step 31 and from which the seamless processing header HD has been deleted.

[0061] In step S35, the access port 11 transmits the main signal frame Fm from which the main signal identifier IDm has been deleted from the main frame Fms to the user device U.

[0062] If it is determined in step S32 that the frame is not the main frame Fms, that is, the frame is the monitoring frame Fcs, then in step S36, the identifier addition and deletion unit 15 deletes the monitoring signal identifier IDc from the monitoring frame Fcs.

[0063] In step S37, the monitoring function unit 14 executes the monitoring process using the monitoring signal frame Fc from which the monitoring signal identifier IDc has been deleted from the monitoring frame.

[0064] As described above, according to the first embodiment, the non-interruptive device 1 includes an identifier adding unit 12 that adds a main signal identifier IDm indicating that it is the main signal frame Fm to the main signal frame Fm received from the user device U, a non-interruptive processing unit 13 that duplicates the main signal frame Fm to which the main signal identifier IDm is added, and adds a non-interruptive processing header HD to the main signal frame Fm to which the main signal identifier IDm is added to generate a first main frame Fms1, and a second main frame Fms2 obtained by adding a non-interruptive processing header HD to the duplicated main signal frame Fm to which the main signal identifier IDm is added, a first transport 16 that transmits the first main frame Fms1 to the first relay switch 3A, a second transport 17 that transmits the second main frame Fms2 to the first relay switch 3A, a monitoring function unit 14 that generates a monitoring signal frame Fc, and an identifier adding / deleting unit 15 that generates a monitoring frame Fcs by adding a monitoring signal identifier IDc for identifying that it is the monitoring signal frame Fc to the monitoring signal frame Fc. Only one of the first transport 16 and the second transport 17 transmits the monitoring frame Fcs to the relay switch 3.

[0065] Thereby, the non-interruptive device 1 can be remotely monitored with a simple configuration. Specifically, the non-interruptive device 1 can transmit the monitoring signal frame Fc to the monitoring device 5 without executing the process of attaching the non-interruptive processing header HD. For this reason, the processing load on the non-interruptive device 1 is reduced. In addition, since the non-interruptive device 1 transmits the monitoring frame Fcs without the non-interruptive processing header HD to the monitoring device 5 via one communication line, as shown in FIG. 11, there is no need to provide a non-interruptive device between the monitoring network switch 4 and the relay switch 3. Therefore, the non-interruptive redundancy switching system 100 including the non-interruptive device 1 can be simply configured.

[0066] Further, the non-interrupt device 1 determines whether the frame is a main frame or a monitoring frame Fcs based on whether the identifier attached to the frame received by the first transport 16 and the second transport 17 is the main signal identifier IDm or the monitoring signal identifier IDc. The non-interrupt device 1 further includes a signal distribution unit 18 that outputs the main frame to the non-interrupt processing unit 13 and outputs the monitoring frame Fcs to the monitoring function unit 14. The non-interrupt processing unit 13 selects a frame for transmission to the user device U based on the non-interrupt processing header HD included in the main frame, and the monitoring function unit 14 executes a monitoring process using the monitoring frame Fcs.

[0067] Thereby, in the non-interrupt device 1, the monitoring function unit 14 can execute a monitoring process based on the monitoring signal frame Fc included in the monitoring frame Fcs received via either of the two communication lines in the communication using PRP. For this reason, the non-interrupt device 1 does not need to provide a communication line NW91 for transmitting and receiving the monitoring signal frame Fc as shown in FIG. 10A, and also does not need to provide a communication line NW92 for connecting the access port AP from the monitoring port CP as shown in FIG. 10B. Therefore, the non-interrupt redundant switching system 100 including the non-interrupt device 1 can be simply configured.

[0068] <<Second Embodiment>> In the second embodiment, the non-interrupt redundant switching system 100 includes a non-interrupt device 1A-1 and a non-interrupt device 1B-1 instead of the non-interrupt devices 1A and 1B shown in FIG. 1. In the second embodiment, the same reference numerals are added to the same functional units as in the first embodiment, and the description thereof is omitted. Hereinafter, the non-interrupt devices 1A-1 and 1B-1 may be simply referred to as "non-interrupt device 1-1", respectively. Further, the non-interrupt redundant switching system 100 includes a monitoring device 5-1 instead of the monitoring device 5 shown in FIG. 1.

[0069] <Configuration of Non-Interrupt Device> As shown in FIG. 5, the non-interrupt device 1-1 includes an access port 11, an identifier assigning unit 12, a non-interrupt processing unit 13, a monitoring function unit 14, an identifier assigning / deleting unit 15, a first transport 16, a second transport 17, an identifier deleting unit 19, a line status information storage unit 20, a first line monitoring function unit 21, a second line monitoring function unit 22, a line switching unit 23, a first signal distribution unit 24, and a second signal distribution unit 25. The line status information storage unit 20 is constituted by a memory. The first line monitoring function unit 21, the second line monitoring function unit 22, the first signal distribution unit 24, and the second signal distribution unit 25 are constituted by a controller. Also, each functional unit may be configured integrally with other functional units or separately.

[0070] The line status information storage unit 20 stores line status information. The line status information in the second embodiment is information indicating whether the first communication line NW1 is normal and information indicating whether the second communication line NW2 is normal. The first communication line NW1 is a communication line that propagates the first main frame Fms1 transmitted by the first transport 16 to other non-interrupt devices 1-1. The second communication line NW2 is a communication line different from the first communication line NW1 that propagates the second main frame transmitted by the second transport 17 to other non-interrupt devices 1-1.

[0071] The first line monitoring function unit 21 determines whether the first communication line NW1 that propagates the first main frame Fms1 transmitted by the first transport 16 to other non-interrupt devices 1-1 is normal. In the example shown in FIG. 1, the first communication line NW1 is a communication line that connects the first non-interrupt device 1A-1 and the second non-interrupt device 1B-1. Specifically, the first line monitoring function unit 21 determines that the first communication line NW1 is normal when no disconnection is detected in the first communication line NW1, and determines that the first communication line NW1 is not normal when a disconnection is detected in the first communication line NW1. For example, the first line monitoring function unit 21 may detect the occurrence of a disconnection in the first communication line NW1 using Ethernet Continuity Check defined in IEEE802.1ag and ITU-T Y.1731.

[0072] Further, when it is detected that the normality of the first communication line NW1 has changed, the first line monitoring function unit 21 changes the information indicating whether the first communication line NW1 in the line status information stored in the line status information storage unit 20 is normal. Specifically, when the first communication line NW1 changes from a state determined to be normal to a state determined not to be normal, the first line monitoring function unit 21 changes the line status information to indicate that the first communication line NW1 is not normal. Also, when the first communication line NW1 changes from a state determined not to be normal to a state determined to be normal, the first line monitoring function unit 21 changes the line status information to indicate that the first communication line NW1 is normal.

[0073] The second line monitoring function unit 22 determines whether or not a second communication line NW2, which is different from the first communication line NW1 and propagates the second main frame transmitted by the second transport 17 to another non-interruptible device 1-1, is normal. In the example shown in FIG. 1, the second communication line NW2 is a communication line connecting the first non-interruptible device 1A-1 and the second non-interruptible device 1B-1. The specific process for the second line monitoring function unit 22 to monitor the normality of the second communication line NW2 is the same as the specific process for the first line monitoring function unit 21 to monitor the normality of the first communication line NW1.

[0074] When it is determined that the first communication line NW1 is normal, the line switching unit 23 switches the transport for transmitting the monitoring frame Fcs to the first transport 16. When it is determined that the first communication line NW1 is not normal and the second communication line NW2 is normal, the line switching unit 23 switches the transport for transmitting the monitoring frame Fcs to the second transport 17.

[0075] Specifically, the line switching unit 23 determines whether or not the line status information stored in the line status information storage unit 20 indicates that the first communication line NW1 is normal. When it is determined that the line status information indicates that the first communication line NW1 is normal, the line switching unit 23 switches the transport for transmitting the monitoring frame Fcs to the first transport 16. For example, the line switching unit 23 may control the first signal distribution unit 24 to switch the transport for transmitting the monitoring frame Fcs to the first transport 16.

[0076] When it is determined that the first communication line NW1 is not normal, the line switching unit 23 determines whether the line status information indicates that the second communication line NW2 is normal. When it is determined that the line status information indicates that the second communication line NW2 is normal, the line switching unit 23 switches the transport for transmitting the monitoring frame Fcs to the second transport 17. For example, the line switching unit 23 may control the second signal distribution unit 25 to switch the transport for transmitting the monitoring frame Fcs to the second transport 17.

[0077] When it is determined that the line status information indicates that the second communication line NW2 is not normal, the line switching unit 23 does not cause either the first transport 16 or the second transport 17 to transmit the monitoring frame Fcs. Note that when it is determined that the line status information indicates that the second communication line NW2 is not normal, the line switching unit 23 may cause a port (not shown) to output a frame indicating an error. Thereby, the administrator of the seamless redundancy switching system 100 can attempt to recover the first communication line NW1 and the second communication line NW2.

[0078] Also, as described above, when the line switching unit 23 switches the transport (the first transport 16 or the second transport 17) for transmitting the monitoring frame Fcs in accordance with a change in the normality of the communication line, the line switching unit 23 notifies the monitoring network switch 4 of the change in the communication line (the first communication line NW1 or the second communication line NW2) through which the monitoring frame Fcs is transmitted. At this time, the line switching unit 23 may use GARP (Gratuitous Address Resolution Protocol). Thereby, the monitoring network switch 4 can rewrite the MAC (Media Access Control) address table so that the monitoring frame Fcs transmitted from the monitoring device 5 is transmitted to the seamless device 1-1 via the communication line corresponding to the transport switched by the line switching unit 23.

[0079] When the first transport 16 is transmitting the monitoring frame Fcs due to the switching of the line switching unit 23, the first signal distribution unit 24 determines whether the frame received by the first transport 16 is a main frame or a monitoring frame Fcs. Specifically, the first signal distribution unit 24 determines whether the identifier included in the frame received by the first transport 16 is the main signal identifier IDm or the monitoring signal identifier IDs. When the signal distribution unit 18 determines that the identifier is the main signal identifier IDm, it determines that the frame is a main frame, and when it determines that the identifier is the monitoring signal identifier IDs, it determines that the frame is the monitoring frame Fcs.

[0080] Also, when the first signal distribution unit 24 determines that the frame is a main frame, it outputs the main frame to the selector 132 of the seamless processing unit 13. When the first signal distribution unit 24 determines that the frame is the monitoring frame Fcs, it outputs the monitoring frame Fcs to the identifier adding / removing unit 15.

[0081] When the second transport 17 is transmitting the monitoring frame Fcs due to the switching of the line switching unit 23, the second signal distribution unit 25 determines whether the frame received by the second transport 17 is a main frame or a monitoring frame Fcs. The specific processing by the second signal distribution unit 25 is the same as the specific processing by the first signal distribution unit 24.

[0082] <Configuration of Monitoring Device> The monitoring device 5-1 receives the monitoring frame Fcs transmitted from the non-interrupt device 1A via the communication line corresponding to the transport switched by the line switching unit 23 among the first transport 16 and the second transport 17. Further, the monitoring device 5-1 transmits the monitoring frame Fcs to the non-interrupt device 1 via the communication line corresponding to the transport switched by the line switching unit 23 among the first transport 16 and the second transport. As described above, by rewriting the MAC address table in the monitoring network switch 4, the monitoring device 5-1 can transmit the monitoring frame Fcs to the non-interrupt device 1 via the communication line corresponding to the transport switched by the line switching unit 23.

[0083] <Operation of the non-interrupt device> Subsequently, the operation of the non-interrupt device 1-1 according to the second embodiment will be described with reference to FIG. 6. FIG. 6 is a flowchart showing an example of the operation for transmitting the monitoring frame Fcs in the non-interrupt device 1-1 according to the second embodiment. The operation in the non-interrupt device 1-1 described with reference to FIG. 6 corresponds to the non-interrupt redundancy switching method executed by the non-interrupt device 1 according to the second embodiment.

[0084] As shown in FIG. 6, in step S41, the monitoring function unit 14 generates a monitoring signal frame Fc.

[0085] In step S42, the identifier adding / removing unit 15 generates a monitoring frame Fcs by adding a monitoring signal identifier IDc for identifying that it is a monitoring signal frame to the monitoring signal frame Fc.

[0086] In step S43, the line switching unit 23 determines whether the first communication line NW1 for propagating the main frame transmitted by the first transport 16 to another non-interruptible device 1-1 is normal. Specifically, the line switching unit 23 may determine whether the first communication line NW1 is normal by referring to the line status information of the first communication line NW1 stored in the line status information storage unit 20 based on the determination of the first line monitoring function unit 21.

[0087] If it is determined in step S43 that the first communication line NW1 is normal, in step S44, the line switching unit 23 switches the transport for transmitting the monitoring frame Fcs to the first transport 16. For example, the line switching unit 23 may control the first signal distribution unit 24 to switch the transport for transmitting the monitoring frame Fcs to the first transport 16.

[0088] If it is determined in step S43 that the first communication line NW1 is not normal, in step S45, the line switching unit 23 determines whether a second communication line NW2, which is different from the first communication line NW1 and is for propagating the main frame transmitted by the second transport 17 to another non-interruptible device 1-1, is normal. Specifically, the line switching unit 23 may determine whether the second communication line NW2 is normal by referring to the line status information of the second communication line NW2 stored in the line status information storage unit 20 based on the determination of the second line monitoring function unit 22.

[0089] If it is determined in step S45 that the second communication line NW2 is normal, in step S46, the line switching unit 23 switches the transport for transmitting the monitoring frame Fcs to the first transport 16. For example, the line switching unit 23 may control the second signal distribution unit 25 to switch the transport for transmitting the monitoring frame Fcs to the second transport 17.

[0090] If it is determined in step S45 that the second communication line NW2 is not normal, then in step S47, the line switching unit 23 causes a port (not shown) to output a frame indicating an error.

[0091] In step S48, the switched transport transmits the monitoring frame Fcs.

[0092] Note that the operation for the non-stop device 1-1 according to the second embodiment to transmit the main frame is the same as the operation for the non-stop device 1 according to the first embodiment to transmit the main frame. The operation for the non-stop device 1-1 according to the second embodiment to process the received frame is the same as the operation for the non-stop device 1 according to the first embodiment to process the received frame. However, in the non-stop device 1-1 according to the second embodiment, among the first transport 16 and the second transport 17, the transport for which the line switching unit 23 causes to transmit the monitoring frame Fcs based on the line status information receives the monitoring frame Fcs.

[0093] As described above, according to the second embodiment, the non-stop device 1-1 includes a first line monitoring function unit 21 that determines whether the first communication line NW1 for propagating the main frame transmitted by the first transport 16 to other non-stop devices 1-1 is normal, a second line monitoring function unit 22 that determines whether the second communication line NW2 for propagating the main frame transmitted by the second transport 17 to other non-stop devices 1-1 is normal, and a line switching unit 23 that switches the transport for transmitting the monitoring frame Fcs to the first transport 16 when it is determined that the first communication line NW1 is normal, and switches the transport for transmitting the monitoring frame Fcs to the second transport 17 when it is determined that the first communication line NW1 is not normal and the second communication line NW2 is normal.

[0094] As a result, even when either the first communication line NW1 or the second communication line NW2 is abnormal, the non-interrupt device 1-1 can transmit the monitoring frame Fcs to the monitoring device 5. Therefore, even when either the first communication line NW1 or the second communication line NW2 is abnormal, the non-interrupt device 1-1 can be appropriately monitored by the monitoring device 5.

[0095] <<Third Embodiment>> In the third embodiment, the non-interrupt redundancy switching system 100 includes a non-interrupt device 1A-2 and a non-interrupt device 1B-2 instead of the non-interrupt devices 1A and 1B shown in FIG. 1. In the third embodiment, the same reference numerals are added to the functional units that are the same as those in the first and second embodiments, and the description thereof is omitted. Hereinafter, the non-interrupt device 1A-2 and the non-interrupt device 1B-2 may be simply referred to as "non-interrupt device 1-2". Further, the non-interrupt redundancy switching system 100 includes a monitoring device 5-2 instead of the monitoring device 5 shown in FIG. 1. Also, each functional unit may be configured integrally with other functional units or separately.

[0096] As shown in FIG. 7, the non-interrupt device 1-2 includes an access port 11, an identifier assigning unit 12, a non-interrupt processing unit 13, a monitoring function unit 14, an identifier assigning / deleting unit 15, a first transport 16, a second transport 17, an identifier deleting unit 19, a line status information storage unit 20-2, a line switching unit 23-2, a first signal distributing unit 24, a second signal distributing unit 25, and a line monitoring function unit 26. The line status information storage unit 20-2 is configured by a memory. The line switching unit 23-2 and the line monitoring function unit 26 are configured by a controller.

[0097] The line status information storage unit 20-2 stores line status information. In the third embodiment, the line status information is information indicating whether the third communication line NW3 is normal and information indicating whether the fourth communication line NW4 is normal. The third communication line is a communication line that propagates the frame transmitted by the first transport 16 to the monitoring device 5. The fourth communication line is a communication line that propagates the frame transmitted by the second transport 17 to the monitoring device 5. As shown in FIG. 1, the portion from the non-interrupt device 1 to the relay switch 3 in the third communication line NW3 is the portion itself from the non-interrupt device 1 to the relay switch 3 in the first communication line NW1 described above. Also, the portion from the non-interrupt device 1 to the relay switch 3 in the fourth communication line NW4 is the portion itself from the non-interrupt device 1 to the relay switch 3 in the second communication line NW2 described above.

[0098] The line monitoring function unit 26 determines whether the third communication line NW3 that propagates the monitoring frame Fcs transmitted by the first transport 16 to the monitoring device 5 is normal. The line monitoring function unit 26 determines whether the fourth communication line NW4 that propagates the frame transmitted by the second transport 17 to the monitoring device 5 is normal.

[0099] Specifically, when the line monitoring function unit 26 does not detect the occurrence of a disconnection in the third communication line NW3, it determines that the third communication line NW3 is normal. When the occurrence of a disconnection is detected in the third communication line NW3, it determines that the third communication line NW3 is not normal. For example, the line monitoring function unit 26 may cause the first transport 16 to send a PING (Packet InterNet Groper) defined in RFC (Request For Comments) 792 to the monitoring device 5 to determine the occurrence of a disconnection in the third communication line NW3. Specifically, after the first transport 16 sends a PING to the monitoring device 5, the line monitoring function unit 26 determines that no disconnection has occurred in the third communication line NW3 when it receives a response to the PING, and can determine that a disconnection has occurred in the third communication line NW3 when it does not receive a response to the PING.

[0100] Also, when the line monitoring function unit 26 detects that the normality of the third communication line NW3 has changed, it changes the information indicating whether the third communication line NW3 is normal in the line status information stored in the line status information storage unit 20-2. Specifically, when the third communication line NW3 changes from a state where it was determined to be normal to a state where it is determined not to be normal, the line monitoring function unit 26 changes the line status information to indicate that the third communication line NW3 is not normal. Also, when the third communication line NW3 changes from a state where it was determined not to be normal to a state where it is determined to be normal, the line monitoring function unit 26 changes the line status information to indicate that the third communication line NW3 is normal.

[0101] The specific process for the line monitoring function unit 26 to monitor the normality of the fourth communication line NW4 is the same as the specific process for monitoring the normality of the third communication line NW3.

[0102] The line switching unit 23-2 switches the transport for transmitting the monitoring frame Fcs to either the first transport 16 or the second transport 17 based on the normality of the communication line. Specifically, the line switching unit 23-2 determines whether the line status information stored in the line status information storage unit 20-2 indicates that the third communication line NW3 is normal. When it is determined that the line status information indicates that the third communication line NW3 is normal, the line switching unit 23-2 switches the transport for transmitting the monitoring frame Fcs to the first transport 16. For example, the line switching unit 23-2 may control the first signal distribution unit 24 to switch the transport for transmitting the monitoring frame Fcs to the first transport 16.

[0103] When it is determined that the line status information indicates that the third communication line NW3 is not normal, the line switching unit 23-2 determines whether the line status information indicates that the fourth communication line NW4 is normal. When it is determined that the line status information indicates that the fourth communication line NW4 is normal, the line switching unit 23-2 switches the transport for transmitting the monitoring frame Fcs to the second transport 17. For example, the line switching unit 23-2 may control the second signal distribution unit 25 to switch the transport for transmitting the monitoring frame Fcs to the second transport 17.

[0104] When it is determined that the line status information indicates that the fourth communication line NW4 is not normal, the line switching unit 23 does not cause either the first transport 16 or the second transport 17 to transmit the monitoring frame Fcs. Also, when it is determined that the line status information indicates that the fourth communication line NW4 is not normal, the line switching unit 23-2 may output a frame indicating an error to a port (not shown). Thereby, the administrator of the seamless redundant switching system 100 can attempt to recover the third communication line NW3 and the fourth communication line NW4.

[0105] Also, as described above, when the line switching unit 23-2 switches the transport (the first transport 16 or the second transport 17) that transmits the monitoring frame Fcs in accordance with the change in the normality of the communication line, it notifies the monitoring network switch 4 of the change in the communication line (the third communication line NW3 or the fourth communication line NW4) through which the monitoring frame Fcs is transmitted. At this time, the line switching unit 23-2 may use GARP. As a result, the monitoring network switch 4 can rewrite the MAC address table so that the monitoring frame Fcs transmitted from the monitoring device 5 is transmitted to the non-stop device 1-2 via the communication line corresponding to the transport switched by the line switching unit 23-2.

[0106] <Configuration of Monitoring Device> The monitoring device 5-2 receives the monitoring frame Fcs transmitted from the non-stop device 1A via the communication line corresponding to the transport switched by the line switching unit 23-2 among the first transport 16 and the second transport. Also, the monitoring device 5-2 transmits the monitoring frame Fcs to the non-stop device 1 via the communication line corresponding to the transport switched by the line switching unit 23-2 among the first transport 16 and the second transport. As described above, since the MAC address table is rewritten in the monitoring network switch 4, the monitoring device 5-2 can transmit the monitoring frame Fcs to the non-stop device 1 via the communication line corresponding to the transport switched by the line switching unit 23-2.

[0107] <Operation of Non-Stop Device> Subsequently, the operation of the non-stop device 1-2 according to the third embodiment will be described with reference to FIG. 8. FIG. 8 is a flowchart showing an example of the operation for transmitting the monitoring frame Fcs in the non-stop device 1-2 according to the third embodiment. The operation in the non-stop device 1-2 described with reference to FIG. 8 corresponds to the non-stop redundancy switching method executed by the non-stop device 1 according to the third embodiment.

[0108] In step S51, the monitoring function unit 14 generates a monitoring signal frame Fc.

[0109] In step S52, the identifier adding / removing unit 15 generates a monitoring frame Fcs by adding a monitoring signal identifier IDc for identifying that it is a monitoring signal frame to the monitoring signal frame Fc.

[0110] In step S53, the line switching unit 23-2 determines whether the third communication line NW3 for propagating the monitoring frame Fcs transmitted by the first transport 16 to the monitoring device 5 is normal. Specifically, the line switching unit 23-2 may determine whether the third communication line NW3 is normal by referring to the line status information stored in the line status information storage unit 20-2 based on the determination of the line monitoring function unit 26.

[0111] If it is determined in step S53 that the third communication line NW3 is normal, in step S54, the line switching unit 23-2 switches the transport for transmitting the monitoring frame Fcs to the first transport 16. For example, the line switching unit 23-2 may control the first signal distribution unit 24 to switch the transport for transmitting the monitoring frame Fcs to the first transport 16.

[0112] If it is determined in step S53 that the third communication line NW3 is not normal, in step S55, the line switching unit 23-2 determines whether a fourth communication line NW4 different from the third communication line NW3 for propagating the monitoring frame transmitted by the second transport 17 to the monitoring device 5 is normal. Specifically, the line switching unit 23-2 may determine whether the fourth communication line NW4 is normal by referring to the line status information stored in the line status information storage unit 20-2 based on the determination of the line monitoring function unit 26.

[0113] When it is determined in step S55 that the fourth communication line NW4 is normal, in step S56, the line switch unit 23-2 switches the transport for transmitting the monitoring frame Fcs to the second transport 17. For example, the line switch unit 23-2 may control the second signal distribution unit 25 to switch the transport for transmitting the monitoring frame Fcs to the second transport 17.

[0114] When it is determined in step S55 that the second communication line NW2 is not normal, in step S57, the line switch unit 23-2 causes a frame indicating an error to be output to a port (not shown).

[0115] In step S58, the switched transport transmits a monitoring frame.

[0116] Note that the operation of the seamless device 1-2 according to the third embodiment for transmitting the main frame is the same as the operation of the seamless device 1 according to the first embodiment for transmitting the main frame. The operation of the seamless device 1-2 according to the third embodiment for processing the received frame is the same as the operation of the seamless device 1 according to the first embodiment for processing the received frame. However, in the seamless device 1-2 according to the third embodiment, among the first transport 16 and the second transport 17, the transport to which the line switch unit 23-2 causes the monitoring frame Fcs to be transmitted based on the line status information receives the frame.

[0117] As described above, according to the third embodiment, the non-interruptible device 1-2 determines whether the third communication line NW3 for propagating the monitoring frame Fcs transmitted by the first transport 16 to the monitoring device 5 is normal, and determines whether the fourth communication line NW4 for propagating the frame transmitted by the second transport 17 to the monitoring device 5 is normal. A line monitoring function unit 26; when it is determined that the third communication line NW3 is normal, the first transport 16 is made to transmit the monitoring frame Fcs; when it is determined that the third communication line NW3 is not normal and the fourth communication line NW4 is normal, a line switching unit 23-2 that switches the transport for transmitting the monitoring frame Fcs to the first transport 16.

[0118] Thereby, the non-interruptible device 1-2, like the non-interruptible device 1-1, can transmit the monitoring frame Fcs to the monitoring device 5 even when either the third communication line NW3 or the fourth communication line NW4 is not normal. Therefore, the non-interruptible device 1-1 can be appropriately monitored by the monitoring device 5 even when either the third communication line NW3 or the fourth communication line NW4 is not normal.

[0119] <Program> The above-mentioned non-interruptible device 1, non-interruptible device 1-1, and non-interruptible device 1-2 can be realized by a computer 101. Also, a program for causing the above-mentioned non-interruptible device 1, non-interruptible device 1-1, and non-interruptible device 1-2 to function may be provided. Further, the program may be stored in a storage medium or provided through a network. FIG. 9 is a block diagram showing a schematic configuration of a computer 101 that functions as the non-interruptible device 1. Computers that function as the non-interruptible device 1-1 and the non-interruptible device 1-2 may be configured in the same manner as the computer 101. Here, the computer 101 may be a general-purpose computer, a dedicated computer, a workstation, a PC (Personal Computer), an electronic notebook, or the like. The program instructions may be program codes, code segments, etc. for executing necessary tasks.

[0120] As shown in FIG. 9, the computer 101 includes a processor 110, a ROM (Read Only Memory) 120, a RAM (Random Access Memory) 130, a storage 140, an input unit 1050, an output unit 1060, and a communication interface (I / F) 170. Each component is connected to be communicable with each other via a bus 180. Specifically, the processor 110 is a CPU (Central Processing Unit), MPU (Micro Processing Unit), GPU (Graphics Processing Unit), DSP (Digital Signal Processor), SoC (System on a Chip), etc., and may be configured by a plurality of processors of the same type or different types.

[0121] Processor 110 controls each component and performs various arithmetic operations. That is, processor 110 reads a program from ROM 120 or storage 140 and executes the program using RAM 130 as a working area. Processor 110 controls each of the above components and performs various arithmetic operations according to the program stored in ROM 120 or storage 140. In the above-described embodiment, the program according to the present disclosure is stored in ROM 120 or storage 140.

[0122] The program may be stored in a computer-readable storage medium. By using such a storage medium, it is possible to install the program in computer 101. Here, the storage medium in which the program is stored may be a non-transitory storage medium. The non-transitory storage medium is not particularly limited, and may be, for example, a CD-ROM, a DVD-ROM, a USB (Universal Serial Bus) memory, or the like. Further, this program may be in a form downloaded from an external device via a network.

[0123] ROM 120 stores various programs and various data. RAM 130 temporarily stores a program or data as a working area. Storage 140 is composed of an HDD (Hard Disk Drive) or an SSD (Solid State Drive), and stores various programs and various data including an operating system.

[0124] Input unit 1050 includes one or more input interfaces that receive a user's input operation and acquire information based on the user's operation. For example, input unit 1050 may be a pointing device, a keyboard, a mouse, etc., but is not limited thereto.

[0125] The output unit 1060 includes one or more output interfaces for outputting information. For example, the output unit 1060 may be, but is not limited to, a display for outputting information visually or a speaker for outputting information audibly. Note that when the output unit 1060 is a touch panel type display, it also functions as the input unit 1050.

[0126] The communication interface (I / F) 170 is an interface for communicating with an external device.

[0127] Regarding the above embodiments, the following additional remarks are disclosed. [Supplementary Note 1] A non-stop redundant switching device that communicates with another non-stop redundant switching device using non-stop redundant switching processing via a first communication line and a second communication line, comprising a controller, a first communication interface, and a second communication interface, The controller adds a main signal identifier indicating that it is a main signal frame to the main signal frame received from the user device, duplicates the main signal frame with the main signal identifier added, and to the main signal frame with the main signal identifier added that is the original of the duplication, adds a non-stop processing header indicating the order in which the main signal frame is transmitted to generate a first main frame, and to the duplicated main signal frame with the main signal identifier added, adds a non-stop processing header indicating the order in which the main signal frame is transmitted to generate a second main frame; a non-stop processing unit, The first communication interface transmits the first main frame to a first relay switch via the first communication line, The second communication interface transmits the second main frame to a second relay switch different from the first relay switch via the second communication line, The controller generates a monitoring signal frame, generates a monitoring frame by adding a monitoring signal identifier for identifying that it is a monitoring signal frame to the monitoring signal frame A non-stop redundancy switching device that transmits the monitoring frame via only one of the first communication interface and the second communication interface through the corresponding first communication line or the second communication line. [Additional item 2] The controller Based on whether the identifier attached to the frame received by the transport that transmits the monitoring frame among the first transport and the second transport is the main signal identifier or the monitoring signal identifier, determines whether the frame is the main frame or the monitoring frame, outputs the main frame to the non-stop processing unit, and outputs the monitoring frame to the monitoring function unit. The non-stop processing unit selects a main frame for transmission to the user device based on the non-stop processing header included in the main frame. The monitoring function unit executes a monitoring process using the monitoring frame. The non-stop redundancy switching device according to claim 1. [Additional item 3] The controller Determines whether the first communication line for propagating the first main frame transmitted by the first transport to another non-stop redundancy switching device is normal. Determines whether the second communication line for propagating the second main frame transmitted by the second transport to the other non-stop redundancy switching device is normal. When it is determined that the first communication line is normal, switches the transport for transmitting the monitoring frame to the first transport. When it is determined that the first communication line is not normal and the second communication line is normal, switches the transport for transmitting the monitoring frame to the second transport. The non-stop redundancy switching device according to claim 1 or 2. [Additional item 4] The controller Determine whether the third communication line for propagating the monitoring frame transmitted by the first transport to the monitoring device is normal, and determine whether the fourth communication line for propagating the frame transmitted by the second transport to the monitoring device is normal. When it is determined that the third communication line is normal, switch the transport for transmitting the monitoring frame to the first transport. When it is determined that the third communication line is not normal and the fourth communication line is normal, switch the transport for transmitting the monitoring frame to the second transport. The seamless redundant switching device according to any one of claims 1 to 3. [Claim 5] In a seamless redundant switching method executed by a seamless redundant switching device that communicates with another seamless redundant switching device using seamless redundant switching processing via a first communication line and a second communication line. Attach a main signal identifier indicating that it is a main signal frame to the main signal frame received from the user device. Duplicate the main signal frame to which the main signal identifier is attached, and attach a seamless processing header indicating the order in which the main signal frame is transmitted to the main signal frame to which the main signal identifier is attached as the original of the duplication to generate a first main frame, and attach a seamless processing header indicating the order in which the main signal frame is transmitted to the duplicated main signal frame to which the main signal identifier is attached to generate a second main frame. Transmit the first main frame to the first relay switch via the first communication line by the first transport. Transmit the second main frame to a second relay switch different from the first relay switch via the second communication line by a second transport different from the first transport. Generate a monitoring signal frame. Generate a monitoring frame by attaching a monitoring signal identifier for identifying that it is a monitoring signal frame to the monitoring signal frame. A non-interruptible redundancy switching method for transmitting the monitoring frame via either the corresponding first communication line or the second communication line only by one of the first transport and the second transport. [Appended Claim 6] In a non-interruptible redundancy switching system including another non-interruptible redundancy switching device, two non-interruptible redundancy switching devices that communicate using non-interruptible redundancy switching processing, a relay switch, and a monitoring device via a first communication line and a second communication line, Each of the two non-interruptible redundancy switching devices is a non-interruptible redundancy switching device that communicates with another non-interruptible redundancy switching device using non-interruptible redundancy switching processing via a first communication line and a second communication line, and has a controller, a first communication interface, and a second communication interface. The controller: Adds a main signal identifier indicating that it is a main signal frame to the main signal frame received from the user device. Replicates the main signal frame with the main signal identifier added, and adds a non-interruptible processing header indicating the order in which the main signal frame is transmitted to the main signal frame with the main signal identifier added that is the original of the replication to generate a first main frame, and adds a non-interruptible processing header indicating the order in which the main signal frame is transmitted to the replicated main signal frame with the main signal identifier added to generate a second main frame. The first communication interface transmits the first main frame to a first relay switch via the first communication line. The second communication interface transmits the second main frame to a second relay switch different from the first relay switch via the second communication line. The controller: Generates a monitoring signal frame. Generates a monitoring frame by adding a monitoring signal identifier for identifying that it is a monitoring signal frame to the monitoring signal frame. A non-stop redundancy switching system in which only one of the first communication interface and the second communication interface transmits the monitoring frame via the corresponding first communication line or the second communication line. [Appended Claim 7] A non-transitory storage medium storing a program executable by a computer, the non-transitory storage medium storing a program that causes the computer to operate as the non-stop redundancy switching device according to claim 1 or 2.

[0128] All documents, patent applications, and technologies described in this specification are incorporated herein by reference to the same extent as if each individual document, patent application, and technology were specifically and individually indicated to be incorporated by reference.

[0129] Although the above-described embodiments have been described as representative examples, it will be apparent to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the present disclosure. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications or changes are possible without departing from the scope of the claims.

Explanation of Reference Numerals

[0130] 1, 1A, 1B, 1-1, 1A-1, 1B-1, 1-2, 1A-2, 1B-2 Non-stop redundancy switching device (non-stop device) 3, 3A, 3B Relay switch 4 Monitoring network switch 5 Monitoring device 11 Access port 12 Identifier assigning unit 13 Non-stop redundancy switching processing unit (non-stop processing unit) 14 Monitoring function unit 15 Identifier assigning and deleting unit 16 First transport 17 Second transport 18 Signal distribution unit 19 Identifier deleting unit 20, 20-2 Line status information storage unit 21 First line monitoring function unit 22 Second line monitoring function unit 23, 23-2 Line switching unit 24 First signal distribution unit 25 Second signal distribution unit 26 Line monitoring function unit 100 Non-interrupt redundant switching system 101 Computer 110 Processor 120 ROM 130 RAM 131 Duplicator 132 Selector 140 Storage 150 Input unit 160 Output unit 170 Communication interface 180 Bus UA, UB User device

Claims

1. An uninterruptible redundancy switching device that communicates with another uninterruptible redundancy switching device via a first communication line and a second communication line using an uninterruptible redundancy switching process, an identifier adding unit that adds a main signal identifier indicating that it is a main signal frame to the main signal frame received from the user device, duplicates the main signal frame to which the main signal identifier is added, and adds an uninterruptible processing header indicating the order in which the main signal frame is transmitted to the main signal frame to which the main signal identifier is added as the original of the duplication, A first main frame, and a second main frame obtained by adding an uninterruptible processing header indicating the order in which the main signal frame is transmitted to the duplicated main signal frame to which the main signal identifier is added, and an uninterruptible processing unit that generates the first main frame and the second main frame, a first transport that transmits the first main frame to a first relay switch via the first communication line, a second transport that transmits the second main frame to a second relay switch different from the first relay switch via the second communication line, a monitoring function unit that generates a monitoring signal frame, an identifier adding / removing unit that generates a monitoring frame by adding a monitoring signal identifier for identifying that it is a monitoring signal frame to the monitoring signal frame, and An uninterruptible redundancy switching device in which only one of the first transport and the second transport transmits the monitoring frame via the corresponding first communication line or the second communication line.

2. Based on whether the identifier attached to the frame received by the transport that transmits the monitoring frame among the first transport and the second transport is the main signal identifier or the monitoring signal identifier, determines whether the frame is the main frame or the monitoring frame, further comprising a signal distribution unit that outputs the main frame to the uninterruptible processing unit and outputs the monitoring frame to the monitoring function unit, the uninterruptible processing unit selects a main frame for transmission to the user device based on the uninterruptible processing header included in the main frame, The uninterruptible redundancy switching device according to claim 1, wherein the monitoring function unit executes a monitoring process using the monitoring frame.

3. A first line monitoring function unit that determines whether a first communication line for propagating the first main frame transmitted by the first transport to another non-interrupt redundant switching device is normal; A second line monitoring function unit that determines whether a second communication line for propagating the second main frame transmitted by the second transport to the other non-interrupt redundant switching device is normal; A line switching unit that switches the transport for transmitting the monitoring frame to the first transport when it is determined that the first communication line is normal, and switches the transport for transmitting the monitoring frame to the second transport when it is determined that the first communication line is not normal and the second communication line is normal; The non-interrupt redundant switching device according to claim 1 or 2, further comprising:

4. A line monitoring function unit that determines whether a third communication line for propagating the monitoring frame transmitted by the first transport to a monitoring device is normal, and determines whether a fourth communication line for propagating the frame transmitted by the second transport to the monitoring device is normal; A line switching unit that switches the transport for transmitting the monitoring frame to the first transport when it is determined that the third communication line is normal, and switches the transport for transmitting the monitoring frame to the second transport when it is determined that the third communication line is not normal and the fourth communication line is normal; The non-interrupt redundant switching device according to claim 1 or 2, further comprising:

5. In a non-interrupt redundant switching method executed by a non-interrupt redundant switching device that communicates with another non-interrupt redundant switching device using non-interrupt redundant switching processing via a first communication line and a second communication line, A step of attaching a main signal identifier indicating that it is a main signal frame to the main signal frame received from the user device; Duplicate the main signal frame with the main signal identifier, and add a seamless processing header indicating the order in which the main signal frame is transmitted to the original main signal frame with the main signal identifier, to generate a first main frame; and generate a second main frame by adding a seamless processing header indicating the order in which the main signal frame is transmitted to the duplicated main signal frame with the main signal identifier. Transmit the first main frame to a first relay switch via the first communication line by the first transport. Transmit the second main frame to a second relay switch different from the first relay switch via the second communication line by a second transport different from the first transport. Generate a monitoring signal frame. Generate a monitoring frame by adding a monitoring signal identifier for identifying that it is a monitoring signal frame to the monitoring signal frame. Transmit the monitoring frame via the corresponding first communication line or the second communication line by only one of the first transport and the second transport. A seamless redundancy switching method including the above steps. In a seamless redundancy switching system including an other seamless redundancy switching device, two seamless redundancy switching devices communicating with each other using seamless redundancy switching processing, a first relay switch, a second relay switch, and a monitoring device via a first communication line and a second communication line, Each of the two seamless redundancy switching devices Is a seamless redundancy switching device that communicates with another seamless redundancy switching device using seamless redundancy switching processing via a first communication line and a second communication line, An identifier adding unit that adds a main signal identifier indicating that it is a main signal frame to the main signal frame received from the user device; A seamless processing unit that duplicates the main signal frame with the main signal identifier, and adds a seamless processing header indicating the order in which the main signal frame is transmitted to the original main signal frame with the main signal identifier, to generate a first main frame; and generates a second main frame by adding a seamless processing header indicating the order in which the main signal frame is transmitted to the duplicated main signal frame with the main signal identifier. ​ A first transport that transmits the first main frame to a first relay switch via the first communication line; A second transport that transmits the second main frame to a second relay switch different from the first relay switch via the second communication line; A monitoring function unit that generates a monitoring signal frame; An identifier adding / removing unit that generates a monitoring frame by adding a monitoring signal identifier for identifying that it is a monitoring signal frame to the monitoring signal frame; and A non-interruptible redundancy switching system in which only one of the first transport and the second transport transmits the monitoring frame via the corresponding first communication line or second communication line.

7. A program for causing a computer to function as the non-interruptible redundancy switching device according to claim 1 or 2.

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