Transmitting-side transmission device, receiving-side transmission device, redundancy method for transmitting-side transmission device, redundancy method for receiving-side transmission device, program, and transmission device

Abstract

To effectively utilize a path resource of a relay band while ensuring the same redundancy as a conventional technique.SOLUTION: A transmission side transmission device 40 includes: a first transmitter 20 which has a first switch 21; and a second transmitter 30 which has a second switch 31. A main signal is input to either the first transmitter 20 or the second transmitter 30, the main signal input to the first transmitter 20 is set as the first main signal, and the main signal input to the second transmitter 30 is set as the second main signal. If the first transmitter 20 detects a failure in the first main signal, the second transmitter 30 outputs the second main signal to the first transmitter 20. The first transmitter 20 outputs the input second main signal at a first selector 22.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a transmitting side transmission device, a receiving side transmission device, a redundancy method for a transmitting side transmission device, a redundancy method for a receiving side transmission device, a program, and a transmission device. [Background technology]

[0002] Conventionally, the chassis-type configuration in which the monitoring control unit and the switch (SW) unit are made redundant was the general system configuration method for electric multiplex transmission equipment used by telecommunications carriers. However, in recent years, in response to the rapid increase in data center traffic, space-saving and low-cost box-type electric multiplex transmission equipment has become widespread in order to meet the needs of data center operators. This box-type electric multiplex transmission equipment (hereinafter referred to as the BOX-type electric multiplex transmission equipment) does not have redundant monitoring control units and SW units in order to save space and reduce costs, and is inferior in reliability in the event of a failure or malfunction compared to the chassis-type configuration. For this reason, the MC-LAG (Multi-Chassis Link-AGgregation) configuration is applied to improve the reliability of the BOX-type electric multiplex transmission equipment.

[0003] Furthermore, in conventional electrical multiplex transmission equipment, signals from client devices such as routers and layer 2 switches are mapped to layer 1 and layer 2 logical paths (e.g., OTN (Optical Transport Network), VLAN (Virtual Local Area Network), MPLS (Multi-Protocol Label Switching), etc.) to realize a redundant configuration (path protection) on a logical path basis, thereby improving reliability against failures in electrical multiplex transmission equipment sections (e.g., see non-patent document 1). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] TTC Standard JT-G8031, “Ethernet Linear Protection Switching”, [online], Established on May 31, 2011, Information and Communications Technology Committee, [Retrieved on July 1, 2020], Internet<URL:https: / / www.ttc.or.jp / application / files / 9015 / 5425 / 7356 / JT-G8031v1.pdf> ,pp.15-21 Summary of the Invention [Problem to be solved by the invention]

[0005] We consider the realization of path protection, which has been provided by conventional electrical multiplexing transmission equipment, in an MC-LAG configuration.For example, if the current path protection method is applied to an MC-LAG configuration, path protection is required for each opposing box-type electrical multiplexing transmission equipment (two pairs), so it is necessary to secure twice the number of path resources (active and standby) of the trunk band compared to the conventional chassis-type electrical multiplexing transmission equipment configuration.

[0006] That is, in order to configure path protection between opposing box-type electric multiplexing transmission devices, it is necessary to secure the path resources of the trunk band for both the active and standby. Here, if the traffic distribution method of MC-LAG is set to act-standby, in this case, traffic signals flow only on the active (ACT) side between the box-type electric multiplexing transmission devices, so there is an issue that the path resources secured on the standby (STBY) side are wasted.

[0007] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to ensure the same redundancy as in the conventional technology while effectively utilizing the path resources of the relay band. [Means for solving the problem]

[0008] A transmitting side transmission device according to the present invention comprises: A transmitting side transmission device comprising a first transmitter having a first switch and a second transmitter having a second switch, a primary signal is input to either the first transmitter or the second transmitter, the primary signal input to the first transmitter is defined as a first primary signal, and the primary signal input to the second transmitter is defined as a second primary signal; The first switch of the first transmitter a first selector that outputs either the first main signal input thereto or the second main signal input from the second transmitter; The second switch of the second transmitter a second selector that outputs either the second main signal input thereto or the first main signal input from the first transmitter; When the first transmitter detects a fault in the input first main signal, The first transmitter comprises: outputting a notification that the failure has been detected, thereby switching the input of the main signal from the first transmitter to the second transmitter; The second transmitter comprises: Outputting the input second main signal to the first transmitter; The first transmitter comprises: The second main signal input from the second transmitter is output at the first selector. Effect of the Invention

[0009] According to the present invention, it is possible to ensure the same redundancy as in the conventional case, while effectively utilizing the path resources of the relay band. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram showing a configuration of a transmission device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an explanatory diagram showing a fault location in the transmission device according to the embodiment; [Diagram 3]FIG. 11 is an explanatory diagram showing an example in which a path of a main signal is switched for each failure pattern. [Figure 4] 1 is an explanatory diagram showing a state in which the transmission device according to the embodiment is operating normally without any faults; FIG. [Diagram 5] 10 is a sequence diagram showing the flow of a route switching process executed by a first transmitter and a second transmitter when a failure occurs between a router and a first transmitter in a transmission device according to the present embodiment. FIG. [Figure 6] 10 is a sequence diagram showing the flow of a route switching process executed by a first transmitter and a second transmitter when a failure occurs in the first transmitter in a transmission device according to the present embodiment. FIG. [Figure 7] FIG. 11 is a sequence diagram showing the flow of a route switching process executed by a first receiver and a second receiver when a failure occurs in a section between a first transmitter and a first receiver in a transmission device according to this embodiment. [Figure 8] 10 is a sequence diagram showing the flow of a route switching process executed by a second receiver when a failure occurs in a first receiver in a transmission device according to the present embodiment. FIG. [Figure 9] FIG. 2 is a hardware configuration diagram showing an example of a computer that realizes the functions of a transmitting side transmission device and a receiving side transmission device according to the present embodiment. [Figure 10A] FIG. 1 is an explanatory diagram of an electric multiplexing transmission device showing a path protection configuration by opposing a conventional box-type electric multiplexing transmission device. [Figure 10B] This is an electrical multiplexing transmission device in which an MC-LAG configuration is applied to the configuration shown in FIG. 10A. [Figure 11A] FIG. 10B is an explanatory diagram of an electrical multiplexing transmission device to which a current path protection method is applied to the configuration shown in FIG. 10A. [Figure 11B] 11B is an explanatory diagram of an electrical multiplexing transmission device in which an MC-LAG configuration is applied to the configuration shown in FIG. 11A. [Figure 12] FIG. 1 is an explanatory diagram showing a problem of an electrical multiplexing transmission device to which an MC-LAG configuration is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Next, an embodiment of the present invention will be described. First, a conventional technique will be described as a comparative example.

[0012] <Comparative Example> FIG. 10A is an explanatory diagram of an electric multiplexing transmission device showing a path protection configuration in which a conventional box-type switch (the above-mentioned BOX-type electric multiplexing transmission device) is arranged opposite.

[0013] As shown in FIG. 10A, a conventional electrical multiplexing transmission device is configured to include a router 10P, a first transmitter 20P (BOX-type electrical multiplexing transmission device) having a first switch 21P, a first receiver 120P (BOX-type electrical multiplexing transmission device) having a first switch 121P, and a router 110P.

[0014] In a conventional electrical multiplexing transmission device, a router 10P is connected to a first transmitter 20P by link aggregation (LAG), and a router 110P is connected to a first receiver 120P by link aggregation. The first transmitter 20P and the first receiver 120P are connected by two paths, forming a path protection.

[0015] Here, since the first switch 21P and the first switch 121P are not made redundant, the first transmitter 20P and the first receiver 120P become a single point of failure (SPOF) if a failure occurs in either the first switch 21P or the first switch 121P. In this case, the entire electrical multiplexing transmission device fails, and the router 10P and the router 110P cannot communicate.

[0016] Fig. 10B is an explanatory diagram of an electrical multiplexing transmission device in which an MC (Multi-Chassis)-LAG configuration is applied to the configuration shown in Fig. 10A. The same components as those in Fig. 10A are given the same reference numerals, and the description thereof will be omitted as appropriate.

[0017] As shown in FIG. 10B, an electrical multiplexing transmission device adopting an MC-LAG configuration is configured to include a router 10P, a first transmitter 20P, a second transmitter 30P having a second switch 31P, a first receiver 120P, a second receiver 130P having a second switch 131P, and a router 110P.

[0018] The first transmitter 20P and the second transmitter 30P are connected together and are connected to the router 10P by an MC-LAG. Similarly, the first receiver 120P and the second receiver 130P are connected together and are connected to the router 110P by an MC-LAG.

[0019] FIG. 11A is an explanatory diagram of an electrical multiplexing transmission device in which a current path protection method is applied to the configuration shown in FIG. 10A.

[0020] In the electrical multiplexing transmission device shown in Figure 11A, the first switch 21P and the first switch 121P are configured to select and switch between the first path PS1 or the second path PS2 from the first path PS1 and the second path PS2 that constitute a pair of routes.

[0021] FIG. 11B is an explanatory diagram of an electrical multiplexing transmission device in which an MC-LAG configuration is applied to the configuration shown in FIG. 11A.

[0022] As shown in Fig. 11B, the first transmitter 20P and the second transmitter 30P are connected, and the first receiver 120P and the second receiver 130P are connected. In this case, if the current path protection method is applied to an electric multiplexing transmission device to which the MC-LAG configuration is applied, two pairs of path protection are required for each opposing BOX-type electric multiplexing transmission device, that is, a route for the first path PS1 and the second path PS2, and a route for the third path PS3 and the fourth path PS4, so that the path resources are required twice as much as in the conventional configuration.

[0023] Fig. 12 is an explanatory diagram showing the problems of an electrical multiplexing transmission device to which an MC-LAG configuration is applied. In Fig. 12, the electrical multiplexing transmission device shown in Fig. 11B is described in detail. Note that the same reference numerals are used for the same configurations as those described above, and the description will be omitted as appropriate.

[0024] The electrical multiplex transmission device 200P shown in FIG. 12 includes a transmitting point T and a receiving point R. The transmitting point T and the receiving point R are connected by paths 41P and 42P. The transmitting point T is a facility of a telecommunications carrier in which a transmitting side transmission device 40P is installed. The transmitting point T is provided in Building A. On the other hand, the receiving point R is a facility of a telecommunications carrier in which a receiving side transmission device 140P is installed. The receiving point R is provided in Building B.

[0025] The sending side transmission device 40P is configured to include a first transmitter 20P and a second transmitter 30P. The first transmitter 20P is configured to include a first switch 21P. The first switch 21P duplicates a signal input from the router 10P at a duplication point C1. The first switch 21P duplicates (copies) a first main signal in an electrical layer at the duplication point C1, for example. In this case, the first switch 21P transmits the signal input from the router 10P to the first receiver 120P via the path 41P, and outputs the duplicated signal duplicated at the duplication point C1 to the second switch 31P of the second transmitter 30P.

[0026] The second transmitter 30P is configured to include a second switch 31P. The second switch 31P duplicates the signal input from the router 10P at the duplication point C2. The second switch 31P duplicates (copies) the second main signal in the electrical layer at the duplication point C2, for example. In this case, the second switch 31P transmits the signal input from the router 10P to the second receiver 130P via the path 42P, and outputs the duplicated signal duplicated at the duplication point C2 to the first switch 21P of the first transmitter 20P.

[0027] Here, the signal input from the router 10P to the first transmitter 20P is the first main signal, and the first main signal is the signal during the active state. Also, the signal input from the router 10P to the second transmitter 30P is the second main signal, and the second main signal is the signal during the standby state. Therefore, during the active state, the second main signal during the standby state is not input to the second transmitter 30P. Also, since the second main signal is a backup signal for the first main signal, the first main signal and the second main signal are the same signal.

[0028] On the other hand, the receiving side transmission device 140P is configured to include a first receiver 120P and a second receiver 130P.

[0029] The first receiver 120P is configured to include a first switch 121P. The first switch 121P has a first selector 122P.

[0030] The first selector 122P selects and outputs either the signal input from the first transmitter 20P or the signal input from the second receiver 130P. The first receiver 120P constitutes the active side, and outputs the signal received from the first transmitter 20P when active.

[0031] The second receiver 130P is configured to include a second switch 131P. The second switch 131P has a second selector 132P.

[0032] The second selector 132P selects and outputs either the signal input from the second transmitter 30P or the signal input from the first receiver 120P. The second receiver 130P constitutes the standby side, and outputs the signal received from the second transmitter 30P during standby.

[0033] In this case, it is necessary to secure a path resource BS1 output from the first transmitter 20P and a path resource BS2 output from the second transmitter 30P for each of the paths 41P and 42P. However, since only the path resource BS1 carries signals in the traffic of the paths 41P and 42P when active, the path resource BS2 constituting the standby side is wasted.

[0034] The present invention has been made in consideration of these points, and as shown in FIG. 1 described below, between a transmitting side transmission device 40 and a receiving side transmission device 140, which are box-type electrical multiplex transmission devices, the present invention provides a selector function for selecting a signal in the transmitting side transmission device 40, which is the transmitting side SW, and a copy function for copying a signal to the receiving side transmission device 140, which is the receiving side SW.

[0035] As a result, the present invention can ensure the same redundancy as in the conventional technology while making effective use of the path resources of the relay band.

[0036] <Present embodiment> Hereinafter, a transmission device 200 including a transmitting side transmission device and a receiving side transmission device according to an embodiment of the present invention will be described with reference to the drawings.

[0037] 1 is an explanatory diagram showing the configuration of a transmission device 200 according to this embodiment. Note that the same components as those in the comparative example are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0038] As shown in FIG. 1, the transmission device 200 includes a transmission point T and a receiving point R. The transmission point T and the receiving point R are connected by paths 41 and 42. The transmission point T is a facility of a telecommunications carrier in which a transmitting side transmission device 40 is installed. The transmission point T is provided in Building A. On the other hand, the receiving point R is a facility of a telecommunications carrier in which a receiving side transmission device 140 is installed. The receiving point R is provided in Building B.

[0039] The sending side transmission device 40 at the sending point T and the receiving side transmission device 140 at the receiving point R are box-type switches with fixed switch interfaces. In the transmission device 200, the sending side transmission device 40 and the receiving side transmission device 140 configure path protection and secure path resources for the trunk band. Specifically, path protection is configured by a path 41 between the first transmitter 20 and the first receiver 120, and path protection is configured by a path 42 between the second transmitter 30 and the second receiver 130.

[0040] First, a description will be given of the transmission point T. The transmission point T is configured to include a router 10 and a sending side transmission device 40. The router 10 is a device for relaying data exchange between a plurality of different networks.

[0041] The sending side transmission device 40 includes a first transmitter 20 and a second transmitter 30. The first transmitter 20 includes a first switch 21 and a CPU (Central Processing Unit) 23. The first switch 21 includes a first selector 22.

[0042] The first selector 22 selects and outputs either the first main signal input from the router 10 or a duplicate signal of the second main signal input from the second transmitter. The first transmitter 20 outputs the signal selected by the first selector 22. Here, the signal input from the router 10 to the first transmitter 20 is referred to as the first main signal. Also, the signal input from the router 10 to the second transmitter 30 is referred to as the second main signal. Also, the first main signal is referred to as the signal during active mode, and the second main signal is referred to as the signal during standby mode.

[0043] The first switch 21 duplicates the input first main signal at the duplication point C1. The first switch 21 duplicates (copies) the first main signal at the duplication point C1, for example, in the electrical layer.

[0044] The CPU 23 controls the overall operation of the first transmitter 20, and for example, when a signal failure is detected in the first transmitter 20, controls the signal selection of the first selector 22.

[0045] The second transmitter 30 includes a second switch 31 and a CPU 33. The second switch 31 has a second selector 32.

[0046] The second selector 32 selects and outputs either the input second main signal or a duplicate signal of the first main signal input from the first transmitter. The second transmitter 30 outputs the signal selected by the second selector 32.

[0047] The second switch 31 duplicates the input second main signal at the duplication point C2. The second switch 31 duplicates (copies) the second main signal at the duplication point C2, for example, in the electrical layer.

[0048] The CPU 33 controls the overall operation of the second transmitter 30, and for example, when a signal failure is detected in the second transmitter 30, controls the signal selection of the second selector 32.

[0049] In this embodiment, when the first transmitter 20 detects a fault in the input first main signal, the second transmitter 30 copies the input second main signal and outputs the copy signal of the second main signal to the first transmitter 20. The first transmitter 20 selects the copy signal of the second main signal input from the second transmitter 30 in the first selector 22 and outputs it.

[0050] When the second transmitter 30 detects a signal failure in the first switch 21, the second transmitter 30 selects the input second main signal in the second selector 32 and outputs it.

[0051] Next, a description will be given of the receiving point R. The receiving point R includes a router 110 and a receiving side transmission device 140. The router 110 is a device for relaying data exchange between a plurality of different networks.

[0052] The receiving side transmission device 140 is configured to include a first receiver 120 and a second receiver 130. The first receiver 120 is configured to include a first switch 121 and a CPU 123. The first switch 121 has a first selector 122.

[0053] The first selector 122 selects and outputs either the first main signal (first received signal) input from the first transmitter 20 or a duplicate signal of the second main signal (second received signal) input from the second receiver 130. The first receiver 120 outputs the signal selected by the first selector 122. Here, the signal received by the first receiver 120 from the first transmitter 20 is referred to as the first received signal, and the first received signal is referred to as the active signal. Also, the signal received by the second receiver 130 from the second transmitter 30 is referred to as the second received signal, and the second received signal is referred to as the standby signal.

[0054] The first switch 121 duplicates the input first received signal at the duplication point C3. The first switch 121 duplicates (copies) the first received signal at the duplication point C3, for example, in the electrical layer.

[0055] The CPU 123 controls the overall operation of the first receiver 120, and for example, when a signal failure is detected in the first receiver 120, controls the signal selection of the first selector 122.

[0056] The second receiver 130 is configured to include a second switch 131 and a CPU 133. The second switch 131 has a second selector 132.

[0057] The second selector 132 selects and outputs either the input second received signal or a duplicate signal of the first received signal input from the first receiver 120. The second receiver 130 outputs the signal selected by the second selector 132. During standby, the output of the second selector 132 is blocked.

[0058] The second switch 131 duplicates the input second received signal at the duplication point C4. The second switch 131 duplicates (copies) the second received signal at the duplication point C4, for example, in the electrical layer.

[0059] The CPU 133 controls the overall operation of the second receiver 130, and for example, when a signal failure is detected in the second receiver 130, controls the signal selection of the second selector 132.

[0060] In this embodiment, when the first receiver 120 detects a failure in the first received signal input from the first transmitter 20, the second receiver 130 copies the second received signal input from the second transmitter 30 and outputs the copy signal of the second received signal to the first receiver 120. The first receiver 120 selects the copy signal of the second received signal input from the second receiver 130 in the first selector 122 and outputs it.

[0061] When the second receiver 130 detects a failure in the first switch 121, the second receiver 130 selects the input second received signal in the second selector 132 and outputs it.

[0062] Although the first transmitter 20, the second transmitter 30, the first receiver 120, and the second receiver 130 are each equipped with a corresponding CPU 23, 33, 123, and 133, respectively, this is not limited to this, and there is no particular limitation as long as a CPU is provided in each of the transmitting transmission device 40 and the receiving transmission device 140 and a signal failure can be detected.

[0063] <Path switching sequence of this embodiment> Next, a failure pattern in which the sending side transmission device 40 and the receiving side transmission device 140 each execute path protection in the transmission device 200 according to this embodiment will be described.

[0064] <Outline of route switching sequence> Fig. 2 is an explanatory diagram showing a fault location in the transmission device 200 according to this embodiment. Fig. 3 is an explanatory diagram showing an example in which the path of the main signal is switched for each fault pattern.

[0065] As shown in FIG. 2, ten failure patterns PT1 to PT10 at which failures may occur on a path from the router 10 to the router 110 of the transmission device 200 are shown.

[0066] FIG. 3 shows switching of the main signal path for each failure location for ten failure patterns PT1 to PT10 corresponding to FIG. 2. Of the ten failure patterns PT1 to PT10, failure patterns PT3, PT4, PT6, PT8, and PT9 do not require switching of the signal path even if a failure occurs in the signal.

[0067] On the other hand, in the failure patterns PT1, PT2, PT5, and PT7, the path through which the main signal passes is changed, and therefore a switching sequence occurs. In this embodiment, the failure pattern PT1 is described as Example 1, the failure pattern PT2 is described as Example 2, the failure pattern PT5 is described as Example 3, and the failure pattern PT7 is described as Example 4.

[0068] <Normal operation> First, normal operation will be described. In addition, the initial setting states of the first selector 22 and the second selector 32 of the first transmitter 20 and the second transmitter 30 will be described, and the initial setting states of the first selector 122 and the second selector 132 of the first receiver 120 and the second receiver 130 will be described.

[0069] FIG. 4 is an explanatory diagram showing a state in which the transmission device 200 according to this embodiment is operating normally with no faults in the signal.

[0070] The transmission device 200 includes a router 10, a first transmitter 20, a second transmitter 30, a path 41, a path 42, a first receiver 120, a second receiver 130, and a router 110.

[0071] The router 10 is connected to a first transmitter 20 and a second transmitter 30 by MC-LAG. The first transmitter 20 constitutes the active side, and the second transmitter 30 constitutes the standby side.

[0072] 4, first, the router 10 transmits a first main signal to the first transmitter 20. On the other hand, the second transmitter 30, which constitutes the standby side, blocks the input from the router 10 (SQ501).

[0073] The first switch 21 of the first transmitter 20 inputs the first main signal input from the router 10 to the first selector 22, and also duplicates the first main signal at the duplication point C1, and outputs the duplicated signal of the first main signal to the second selector 32 of the second transmitter 30. The first selector 22 of the first transmitter 20 selects the first main signal and outputs it to the first receiver 120. On the other hand, the second selector 32 of the second transmitter 30 selects the duplicated signal of the first main signal input from the first switch 21 of the first transmitter 20, and outputs it to the second receiver 130 (SQ503).

[0074] The first main signal output from the first selector 22 is input to the first receiver 120 via a path 41. Also, the duplicate signal of the first main signal output from the second selector 32 is input to the second receiver 130 via a path 42 (SQ505).

[0075] The first switch 121 of the first receiver 120 inputs the first received signal (first main signal) input from the first transmitter 20 to the first selector 122, and also duplicates the first received signal at the duplication point C3 and outputs the duplicated signal of the first received signal to the second receiver 130.

[0076] The second switch 131 of the second receiver 130 inputs the second received signal (a duplicate signal of the first main signal) input from the second transmitter 30 to the second selector 132, and duplicates the second received signal at the duplication point C4 and outputs the duplicate signal of the second received signal to the first receiver 120.

[0077] The first selector 122 of the first receiver 120 selects and outputs the first received signal when active. On the other hand, even if the second selector 132 of the second receiver 130 selects the duplicate signal of the first received signal, the output is blocked because it is on the standby side (SQ507).

[0078] The first received signal output from the first receiver 120 is transmitted to the router 110 (SQ509).

[0079] In this way, under normal circumstances, the first main signal transmitted from the router 10 is output from the first selector 122 of the first receiver 120 and transmitted to the router 110 .

[0080] Example 1 In the first embodiment, a failure pattern PT1 shown in FIG. 2 and FIG. 3 will be described. In the first embodiment of the present invention, when the first transmitter 20 detects a failure in the input first main signal, the second transmitter 30 copies the input second main signal and outputs the copy signal of the second main signal to the first transmitter 20. The first transmitter 20 selects the copy signal of the second main signal input from the second transmitter 30 in the first selector 22 and outputs it.

[0081] 5 is a sequence diagram showing the flow of a route switching process (path protection) executed by the first transmitter 20 and the second transmitter 30 when a fault occurs between the router 10 and the first transmitter 20 in the transmission device 201 according to this embodiment. Note that the description of the same processes as those in FIG. 4 will be omitted as appropriate.

[0082] In the first embodiment, when a fault occurs between the router 10 and the first transmitter 20, the first selector 22 of the first transmitter 20 and the second selector 32 of the second transmitter 30 are switched using the fault detection (i.e., fault detection) as a trigger. Note that the fault between the router 10 and the first transmitter 20 is determined based on a fault in a signal received by the first transmitter 20. In this case, the fault between the router 10 and the first transmitter 20 can be detected by detecting the fault in the signal.

[0083] As shown in FIG. 5, when a failure occurs in a signal between the router 10 and the first transmitter 20, the CPU 23 of the first transmitter 20 detects a LOS (Loss of Signal) (SQ001).

[0084] When the CPU 23 of the first transmitter 20 detects LOS of the first main signal, it notifies the router 10 of the occurrence of a fault by sending an LOS notification (SQ003), and at the same time, the first transmitter 20 sends a fault notification to the second transmitter 30 (SQ005).

[0085] When the router 10 receives the LOS notification, it waits to switch the signal transmitted by the router 10 from the first main signal to the second main signal (SQ007). Similarly, the first transmitter 20 and the second transmitter 30 also wait to switch the signal transmitted by the router 10 from the first main signal to the second main signal (SQ009).

[0086] Meanwhile, the CPU 23 of the first transmitter 20 executes a switching process in the first selector 22 to switch from the first main signal in active mode to a duplicate signal of the second main signal in standby mode, and the CPU 33 of the second transmitter 30 executes a switching process in the second selector 32 to switch from the first main signal in active mode to the second main signal in standby mode (SQ011).

[0087] When the switching of the first selector 22 and the second selector 32 is completed, the CPU 23 of the first transmitter 20 and the CPU 33 of the second transmitter 30 send a switching completion notification (SQ013, SQ015), and the router 10, the first transmitter 20 and the second transmitter 30 execute a switching process to switch from the first main signal in active mode to the second main signal in standby mode (SQ017, SQ019).

[0088] When the switching process for switching the transmission signal to the second main signal is completed, the router 10 transmits the second main signal to the second transmitter 30 (SQ021).

[0089] The CPU 33 of the second transmitter 30 duplicates the second primary signal upon receiving it, and outputs the duplicated signal of the second primary signal to the first transmitter 20 (SQ023). The first selector 22 of the first transmitter 20 outputs the duplicated signal of the second primary signal input from the second transmitter 30 to the first receiver 120 via the path 41 (SQ025).

[0090] The first receiver 120 inputs the input first received signal (a duplicate signal of the second main signal) to the first switch 121, and the first selector 122 of the first receiver 120 selects and outputs the first received signal (SQ027).

[0091] The first receiver 120 receives the input first received signal, duplicates the input first received signal at duplication point C3, and transmits the duplicated signal of the first received signal to the second receiver 130.

[0092] In this manner, the first receiver 120 transmits the first received signal to the router 110 (SQ029), and ends the route switching process for the failure pattern PT1. Example 2 In the second embodiment, a failure pattern PT2 shown in FIG. 2 and FIG. 3 will be described. In a second embodiment of the present invention, when a first transmitter 20 detects a signal failure in a first switch 21, a second transmitter 30 selects the input second main signal in a second selector 32 and outputs it.

[0093] Fig. 6 is a sequence diagram showing the flow of a route switching process executed by the first transmitter 20 and the second transmitter 30 when a failure occurs in the first transmitter 20 in the transmission device 202 according to this embodiment. Note that the description of the same processes as those in Figs. 4 and 5 will be omitted as appropriate.

[0094] In the second embodiment, when a failure occurs in the first transmitter 20, the detection of the failure in the first transmitter 20 (the transmitting side transmission device 40) is used as a trigger to execute path control.

[0095] As shown in FIG. 6, when a failure occurs in the first transmitter 20, the CPU 33 of the second transmitter 30 detects LOS (SQ101).

[0096] When the CPU 33 of the second transmitter 30 detects LOS, it notifies the router 10 by LOS notification that a failure has occurred in the first transmitter 20 (SQ103, SQ105), and at the same time, sends an LOS notification to the first receiver 120 (SQ107).

[0097] When the router 10 receives the LOS notification, the router 10 waits to switch the signal transmitted by the router 10 from the first main signal to the second main signal (SQ109).

[0098] When the CPU 123 of the first receiver 120 receives an LOS notification from the second transmitter 30, it performs a switching process to switch the selection in the first selector 122 from the first received signal to a duplicate signal of the second received signal (SQ111).

[0099] The CPU 33 of the second transmitter 30 executes a switching process for switching from the first main signal during active mode to the second main signal during standby mode in the second selector 32 (SQ113).

[0100] Furthermore, when the switching process is completed, the CPU 33 of the second transmitter 30 notifies the router 10 of the completion of switching (SQ115, SQ117), and the router 10 and the second transmitter 30 execute switching process to switch from the first main signal in active mode to the second main signal in standby mode (SQ119, SQ121).

[0101] When the second transmitter 30 completes the switching process to switch to the second main signal during standby, it notifies the user that the switching process is complete (SQ123). Note that this notification that the switching process is complete is a process that can be set arbitrarily depending on the standard or specification.

[0102] When the router 10 receives a notification from the second transmitter 30 that the switching process is complete, the router 10 transmits a second main signal to the second transmitter 30 (SQ125).

[0103] The CPU 33 of the second transmitter 30 selects and outputs the second main signal transmitted from the router 10 in the second selector 32 (SQ127). The second transmitter 30 transmits the second main signal to the second receiver 130 via the path 42 (SQ129).

[0104] The second receiver 130 receives the input second received signal (second main signal), replicates the second received signal at a duplication point C4, and outputs the replicated signal of the second received signal to the first receiver 120. The first receiver 120 outputs the replicated signal of the second received signal input from the second receiver 130 at the first selector 122 (SQ131).

[0105] In this manner, the first receiver 120 transmits a duplicate signal of the second received signal to the router 110 (SQ133), and ends the route switching process for the failure pattern PT2.

[0106] Example 3 In the third embodiment, a failure pattern PT5 shown in FIG. 2 and FIG. 3 will be described. In a third embodiment of the present invention, when the first receiver 120 detects a failure in the input first received signal, the second receiver 130 copies the input second received signal and outputs the copy signal of the second received signal to the first receiver 120. The first receiver 120 selects the copy signal of the second received signal input from the second receiver 130 in the first selector 122 and outputs it.

[0107] Fig. 7 is a sequence diagram showing the flow of a route switching process executed by the first receiver 120 and the second receiver 130 when a failure occurs in the section between the first transmitter 20 and the first receiver 120 in the transmission device 203 according to this embodiment. Note that the description of the same processes as those in Figs. 4, 5, and 6 will be omitted as appropriate.

[0108] In the third embodiment, when a fault occurs in the section between the first transmitter 20 and the first receiver 120, a fault detection (fault detection) in the first receiver 120 triggers switching in the first selector 122 of the first switch 121 of the first receiver 120.

[0109] Here, under normal conditions, the first transmitter 20 outputs a first main signal to the first receiver 120, and the second receiver 130 outputs a duplicate signal of the first main signal to the second receiver 130 (see SQ503 in Figure 4).

[0110] When a fault occurs in the section between the first transmitter 20 and the first receiver 120, the first receiver 120 cannot receive the first main signal and performs fault detection (fault detection).

[0111] As shown in FIG. 7, when a failure occurs in the path 41 between the first transmitter 20 and the first receiver 120, the CPU 123 of the first receiver 120 detects LOS from the first main signal it receives (SQ201).

[0112] In this case, the second receiver 130 receives a duplicate signal of the first main signal (second received signal) output from the second transmitter 30 via the path 42 (SQ505). The second switch 131 of the second receiver 130 further duplicates the duplicate signal of the first main signal at duplication point C4, and outputs a signal obtained by further replicating the duplicate signal of the first main signal, i.e., a duplicate signal of the second received signal, to the first receiver 120.

[0113] As a result, the CPU 123 of the first receiver 120 switches the output signal of the first selector 122 from the first received signal (first main signal) to the duplicate signal of the second received signal (SQ203).

[0114] The first switch 121 of the first receiver 120 outputs a duplicate signal of the second received signal input from the second receiver 130 (SQ205). The first receiver 120 transmits the duplicate signal of the second received signal output from the first switch 121 to the router 110 (SQ207).

[0115] In this manner, the first receiver 120 transmits a duplicate signal of the second received signal to the router 110, and ends the route switching process for failure pattern PT5.

[0116] Example 4 In the fourth embodiment, the failure pattern PT7 shown in FIG. 2 and FIG. 3 will be described. In a fourth embodiment of the present invention, when the second receiver 130 detects a signal failure in the first switch 121 of the first receiver 120, the second receiver 130 selects and outputs the input second received signal in the second selector 132.

[0117] Fig. 8 is a sequence diagram showing the flow of a route switching process executed by the second receiver 130 when a failure occurs in the first receiver 120 in the transmission device 204 according to this embodiment. Note that the same processes as those in Figs. 4, 5, 6, and 7 will not be described as appropriate.

[0118] In the fourth embodiment, when a failure occurs in the first receiver 120, the second receiver 130 executes switching of the second selector 132 in the second receiver 130, triggered by detection of the failure in the first receiver 120.

[0119] Here, under normal circumstances, the first receiver 120 receives the first received signal (first main signal) input from the first transmitter 20 (see SQ505 in FIG. 4) and outputs a duplicate signal of the first received signal to the second receiver 130 (see SQ507 in FIG. 4). The second receiver 130 receives the second received signal (duplicate signal of the first main signal) input from the second transmitter 30 (see SQ505 in FIG. 4) and outputs a duplicate signal of the second received signal to the first receiver 120 (see SQ507 in FIG. 4).

[0120] When a failure occurs in the first receiver 120 , the second receiver 130 detects the failure from a replica signal of the first received signal input from the first receiver 120 .

[0121] 8, when a failure occurs in the first receiver 120, the CPU 133 of the second receiver 130 detects an LOS from a duplicate signal of the first received signal (SQ301). When the CPU 133 detects an LOS, it notifies the router 110 of the LOS (SQ303, SQ305).

[0122] Furthermore, when the CPU 133 of the second receiver 130 detects LOS, it performs a switching process to switch the selection in the second selector 132 from the replica signal of the first received signal to the second received signal (SQ307).

[0123] In addition, the CPU 133 of the second receiver 130 executes a switching process to switch the output signal to be sent to the router 110 from the first receiver 120 to the second receiver 130 (SQ309), and the router 110 executes a process to switch the signal received from the receiving side transmission device 140 from the first receiver 120 to the second receiver 130 (SQ311).

[0124] When the switching process is completed, the second selector 132 of the second receiver 130 selects and outputs the second received signal (SQ313). Then, the second receiver 130 transmits the second received signal from the second selector 132 to the router 110 (SQ315).

[0125] <Hardware configuration> The control of the transmitting side transmission device 40 and the receiving side transmission device 140 according to this embodiment is realized by, for example, a computer 900 as shown in FIG.

[0126] In this case, the computer 900 is provided with a first transmitter 20 having a first switch 21 and a second transmitter 30 having a second switch 31 (see FIG. 1), thereby constituting a transmitting side transmission device 40. The computer 900 is also provided with a first receiver 120 having a first switch 121 and a second receiver 130 having a second switch 131 (see FIG. 1), thereby constituting a receiving side transmission device 140.

[0127] FIG. 9 is a hardware configuration diagram showing an example of a computer 900 that realizes control of the transmitting side transmission device 40 and the receiving side transmission device 140 according to this embodiment.

[0128] The computer 900 has a CPU (Central Processing Unit) 901, a ROM (Read Only Memory) 902, a RAM 903, a HDD (Hard Disk Drive) 904, an input / output I / F (Interface) 905, a communication I / F 906 and a media I / F 907.

[0129] The CPU 901 operates based on a program stored in the ROM 902 or the HDD 904, and realizes control of the transmitting side transmission device 40 and the receiving side transmission device 140 shown in FIG.

[0130] The ROM 902 stores a boot program executed by the CPU 901 when the computer 900 is started, programs related to the hardware of the computer 900, and the like.

[0131] The CPU 901 controls an input device 910 such as a mouse or a keyboard, and an output device 911 such as a display, via an input / output I / F 905. The CPU 901 acquires data from the input device 910 via the input / output I / F 905, and outputs generated data to the output device 911. Note that a GPU or the like may be used as a processor together with the CPU 901.

[0132] The HDD 904 stores programs executed by the CPU 901 and data used by the programs, etc. The communication I / F 906 receives data from other devices via a communication network (e.g., NW (Network) 920) and outputs the data to the CPU 901, and also transmits data generated by the CPU 901 to other devices via the communication network.

[0133] The media I / F 907 reads a program or data stored in the recording medium 912 and outputs it to the CPU 901 via the RAM 903. The CPU 901 loads a program related to a target process from the recording medium 912 onto the RAM 903 via the media I / F 907, and executes the loaded program. The recording medium 912 is an optical recording medium such as a DVD (Digital Versatile Disc) or a PD (Phase change rewritable Disc), a magneto-optical recording medium such as an MO (Magneto Optical disk), a magnetic recording medium, a conductive memory tape medium, a semiconductor memory, or the like.

[0134] For example, when the computer 900 functions as a part of the transmitting transmission device 40 according to this embodiment, a CPU 901 of the computer 900 executes a program loaded on a RAM 903 to realize control of the transmitting transmission device 40. Note that, although the CPU 901 controls the entire transmitting transmission device 40 as a single CPU, a CPU may be provided in each of the first transmitter 20 and the second transmitter 30, like CPU 23 and CPU 33 (see FIG. 1).

[0135] Furthermore, when the computer 900 functions as a part of the receiving-side transmission device 140 according to this embodiment, the CPU 901 of the computer 900 executes a program loaded onto the RAM 903 to realize control of the receiving-side transmission device 140. Similarly, the CPU 901 controls the entire receiving-side transmission device 140 as a single CPU, but may be provided in each of the first receiver 120 and the second receiver 130, like the CPU 123 and the CPU 133 (see FIG. 1).

[0136] The data in the RAM 903 is stored in the HDD 904. The CPU 901 reads and executes a program related to a target process from the recording medium 912. Alternatively, the CPU 901 may read a program related to a target process from another device via a communication network (NW 920).

[0137] <Effects> The effects of the sending side transmission device 40 according to this embodiment will be described below. A transmitting side transmission device 40 according to the present invention is a transmitting side transmission device comprising a first transmitter 20 having a first switch 21 and a second transmitter 30 having a second switch 31, in which the first switch 21 of the first transmitter 20 has a first selector 22 that selects and outputs either an input first main signal or a duplicate signal of the second main signal input from the second transmitter 30, and the second switch 31 of the second transmitter 30 has a second selector 22 that selects and outputs either an input second main signal or a duplicate signal of the first main signal input from the first transmitter 20. The present invention is characterized in that it has a selector 32, and when the first transmitter 20 detects a fault in the input first main signal, the second transmitter 30 duplicates the input second main signal and outputs the duplicated signal of the second main signal to the first transmitter 20, and the first transmitter 20 selects and outputs the duplicated signal of the second main signal input from the second transmitter 30 in the first selector 22, and when the second transmitter 30 detects a fault in the first switch 21, the second transmitter 30 selects and outputs the input second main signal in the second selector 32.

[0138] As a result, when the first transmitter 20 detects a fault in the input first main signal, the second transmitter 30 duplicates the input second main signal and outputs the duplicated signal of the second main signal to the first transmitter 20. The first transmitter 20 selects the duplicated signal of the second main signal input from the second transmitter 30 in the first selector 22 and outputs it.

[0139] When the second transmitter 30 detects a signal failure in the first switch 21, the second transmitter 30 selects the input second main signal in the second selector 32 and outputs it.

[0140] As described above, according to this embodiment, the sending side transmission device 40 can ensure the same redundancy as in the conventional case, while making effective use of the path resources of the relay band.

[0141] Next, the effects of the receiving side transmission device 140 according to this embodiment will be described. A receiving-side transmission device 140 according to the present invention is a receiving-side transmission device comprising a first receiver 120 having a first switch 121 and a second receiver 130 having a second switch 131. The first switch 121 of the first receiver 120 has a first selector 122 that selects and outputs either an input first received signal or a duplicate signal of the second received signal input from the second receiver 130. The second switch 131 of the second receiver 130 has a second selector 122 that selects and outputs either an input second received signal or a duplicate signal of the first received signal input from the first receiver 120. The first receiver 120 has a first selector 122 and a second selector 132, and when the first receiver 120 detects a fault in the input first received signal, the second receiver 130 duplicates the input second received signal and outputs the duplicated signal of the second received signal to the first receiver 120, and the first receiver 120 selects and outputs the duplicated signal of the second received signal input from the second receiver 130 in the first selector 122, and when the second receiver 130 detects a signal fault in the first switch 121, the second receiver 130 selects and outputs the input second received signal in the second selector 132.

[0142] As a result, when the first receiver 120 detects a failure in the first received signal input from the first transmitter 20, the second receiver 130 duplicates the second received signal input from the second transmitter 30 and outputs the duplicated signal of the second received signal to the first receiver 120. The first receiver 120 selects the duplicated signal of the second received signal input from the second receiver 130 in the first selector 122 and outputs it.

[0143] When the second receiver 130 detects a failure in the first switch 121, the second receiver 130 selects the input second received signal in the second selector 132 and outputs it.

[0144] As described above, according to this embodiment, the receiving side transmission device 140 can ensure the same redundancy as in the conventional case, while making effective use of the path resources of the relay band.

[0145] The present invention is not limited to the above-described embodiment, and many modifications can be made by those having ordinary skill in the art within the technical scope of the present invention. [Explanation of symbols]

[0146] 10,110 Routers 20 First Transmitter 21 First Switch 22 First Selector 30 Second transmitter 31 Second Switch 32 Second selector 40. Transmitting equipment 120 First Receiver 121 First Switch 122 First Selector 130 Second Receiver 131 Second Switch 132 Second Selector 140 Receiving transmission equipment 200 Transmission Equipment

Claims

1. A transmitting side transmission device comprising a first transmitter having a first switch and a second transmitter having a second switch, a main signal is input to either the first transmitter or the second transmitter, the main signal input to the first transmitter is defined as a first main signal, and the main signal input to the second transmitter is defined as a second main signal, The first switch of the first transmitter a first selector that outputs either the first main signal input thereto or the second main signal input from the second transmitter; The second switch of the second transmitter a second selector that outputs either the second main signal input thereto or the first main signal input from the first transmitter; When the first transmitter detects a fault in the input first main signal, The first transmitter comprises: outputting a notification indicating that the failure has been detected, thereby switching the input of a main signal from the first transmitter to the second transmitter; The second transmitter comprises: outputting the input second main signal to the first transmitter; The first transmitter comprises: a first selector for selecting a first main signal from the second transmitter and for selecting a second main signal from the first selector;

2. A transmitting side transmission device comprising a first transmitter having a first switch and a second transmitter having a second switch, a main signal is input to either the first transmitter or the second transmitter, the main signal input to the first transmitter is defined as a first main signal, and the main signal input to the second transmitter is defined as a second main signal, The first switch of the first transmitter a first selector that outputs either the first main signal input thereto or the second main signal input from the second transmitter; The second switch of the second transmitter a second selector that outputs either the second main signal input thereto or the first main signal input from the first transmitter; If the second transmitter detects a fault in the first switch, The second transmitter comprises: outputting a notification that the failure has been detected, thereby switching the input of a main signal from the first transmitter to the second transmitter; a second selector for outputting the second main signal input thereto;

3. A receiving-side transmission device comprising a first receiver having a first switch and a second receiver having a second switch, a reception signal is output from either the first receiver or the second receiver, the reception signal input to the first receiver is defined as a first reception signal, and the reception signal input to the second receiver is defined as a second reception signal; The first switch of the first receiver a first selector that outputs either the first received signal input thereto or the second received signal input from the second receiver; The second switch of the second receiver a second selector that outputs either the second received signal input thereto or the first received signal input from the first receiver; When the first receiver detects a fault in the input first received signal, The second receiver comprises: Outputting the input second reception signal to the first receiver; The first receiver comprises: a first selector for selecting a second reception signal from the second receiver and for selecting an external device from the first selector;

4. A receiving-side transmission device comprising a first receiver having a first switch and a second receiver having a second switch, a reception signal is output from either the first receiver or the second receiver, the reception signal input to the first receiver is defined as a first reception signal, and the reception signal input to the second receiver is defined as a second reception signal; The first switch of the first receiver a first selector that outputs either the first received signal input thereto or the second received signal input from the second receiver; The second switch of the second receiver a second selector that outputs either the second received signal input thereto or the first received signal input from the first receiver; if the second receiver detects a signal failure at the first switch, The second receiver comprises: outputting a notification of the detection of the failure to an external device, thereby switching reception from the first receiver to reception from the second receiver; a second selector for selecting a second reception signal from the first reception signal and outputting the second reception signal to the external device;

5. A method for providing redundancy to a transmission device on a sending side, the method comprising: a main signal is input to either the first transmitter or the second transmitter, the main signal input to the first transmitter is defined as a first main signal, and the main signal input to the second transmitter is defined as a second main signal, the first switch of the first transmitter has a first selector that outputs either the first main signal input thereto or the second main signal input from the second transmitter; the second switch of the second transmitter has a second selector that outputs either the second main signal input thereto or the first main signal input from the first transmitter; The sending side transmission device When a failure is detected in the first main signal inputted to the first transmitter, switching an input of a main signal from the first transmitter to the second transmitter by outputting a notification indicating that the failure has been detected by the first transmitter; a step of the second transmitter outputting the second main signal input to the first transmitter; a step of the first transmitter outputting the second main signal input from the second transmitter at the first selector; A redundancy method comprising:

6. A method for providing redundancy to a transmission device on a sending side, the method comprising: a main signal is input to either the first transmitter or the second transmitter, the main signal input to the first transmitter is defined as a first main signal, and the main signal input to the second transmitter is defined as a second main signal, the first switch of the first transmitter has a first selector that outputs either the first main signal input thereto or the second main signal input from the second transmitter; the second switch of the second transmitter has a second selector that outputs either the second main signal input thereto or the first main signal input from the first transmitter; The sending side transmission device When a failure of the first switch is detected in the second transmitter, switching an input of a main signal from the first transmitter to the second transmitter by outputting a notification indicating that the failure has been detected by the second transmitter; a step of the second transmitter outputting the second main signal inputted at the second selector; A redundancy method comprising:

7. A method for providing redundancy to a receiving-side transmission device including a first receiver having a first switch and a second receiver having a second switch, the method comprising: a reception signal is output from either the first receiver or the second receiver, the reception signal input to the first receiver is defined as a first reception signal, and the reception signal input to the second receiver is defined as a second reception signal; the first switch of the first receiver has a first selector that outputs either the first received signal input thereto or the second received signal input from the second receiver; the second switch of the second receiver has a second selector that outputs either the second received signal input thereto or the first received signal input from the first receiver; The receiving side transmission device When a failure is detected in the first reception signal inputted to the first receiver, a step of the second receiver outputting the second received signal to the first receiver; a step of the first receiver outputting the second reception signal input from the second receiver to an external device at the first selector; A redundancy method comprising:

8. A method for providing redundancy to a receiving-side transmission device including a first receiver having a first switch and a second receiver having a second switch, the method comprising: a reception signal is output from either the first receiver or the second receiver, the reception signal input to the first receiver is defined as a first reception signal, and the reception signal input to the second receiver is defined as a second reception signal; the first switch of the first receiver has a first selector that outputs either the first received signal input thereto or the second received signal input from the second receiver; the second switch of the second receiver has a second selector that outputs either the second received signal input thereto or the first received signal input from the first receiver; The receiving side transmission device When the second receiver detects a failure of the signal of the first switch, a step of switching reception from the first receiver to reception from the second receiver by outputting a notification of the detection of the failure by the second receiver to an external device; a step of the second receiver outputting the second received signal inputted to the external device at the second selector; A redundancy method comprising:

9. A program to be executed by a computer including a first transmitter having a first switch and a second transmitter having a second switch, a main signal is input to either the first transmitter or the second transmitter, the main signal input to the first transmitter is defined as a first main signal, and the main signal input to the second transmitter is defined as a second main signal, When a failure is detected in the first main signal inputted to the first transmitter as a transmitting side transmission device, a step of switching an input of a main signal from the first transmitter to the second transmitter by outputting a notification that the first transmitter has detected the failure; a step of the second transmitter outputting the second main signal inputted thereto to the first transmitter; a step of the first transmitter outputting the second main signal input from the second transmitter at a first selector of the first transmitter; A program for executing the above.

10. A program to be executed by a computer including a first transmitter having a first switch and a second transmitter having a second switch, a main signal is input to either the first transmitter or the second transmitter, the main signal input to the first transmitter is defined as a first main signal, and the main signal input to the second transmitter is defined as a second main signal, When a failure of the first switch of the first transmitter is detected in the second transmitter as a transmitting side transmission device, a step of switching an input of a main signal from the first transmitter to the second transmitter by outputting a notification that the second transmitter has detected the failure; a step of the second transmitter outputting the second main signal inputted at a second selector of the second transmitter; A program for executing the above.

11. A program to be executed by a computer including a first receiver having a first switch and a second receiver having a second switch, a reception signal is output from either the first receiver or the second receiver, the reception signal input to the first receiver is defined as a first reception signal, and the reception signal input to the second receiver is defined as a second reception signal; When a failure is detected in the first reception signal inputted in the first receiver as a receiving side transmission device, a step of the second receiver outputting the second received signal to the first receiver; a step of the first receiver outputting the second reception signal input from the second receiver to an external device at a first selector of the first receiver; A program for executing the above.

12. A program to be executed by a computer including a first receiver having a first switch and a second receiver having a second switch, a reception signal is output from either the first receiver or the second receiver, the reception signal input to the first receiver is defined as a first reception signal, and the reception signal input to the second receiver is defined as a second reception signal; When the second receiver as a receiving side transmission device detects a failure of the signal of the first switch, a step of switching reception from the first receiver to reception from the second receiver by outputting a notification of the detection of the failure by the second receiver to an external device; a step of the second receiver outputting the second received signal to the external device at a second selector of the second receiver; A program for executing the above.

13. A transmitting side transmission device according to claim 1 ; a receiving side transmission device according to claim 3 or 4, comprising: the first receiver connected to the first transmitter; and the second receiver connected to the second transmitter; A transmission device comprising:

14. A transmitting side transmission device according to claim 2; a receiving side transmission device according to claim 3 or 4, comprising: the first receiver connected to the first transmitter; and the second receiver connected to the second transmitter; A transmission device comprising:

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