JP4793117B2 - COMMUNICATION DEVICE, LINE PROTECTION CONTROL SYSTEM, AND LINE PROTECTION CONTROL METHOD - Google Patents

Description

  The present invention relates to a communication apparatus, a line protection control system, and a line protection control method for switching a line when, for example, a failure occurs in a signal transmission line. In particular, the present invention relates to a 1 + 1 bidirectional line protection in an SDH / SONET transmission system. The present invention relates to a communication apparatus, a line protection control system, and a line protection control method that perform line switching by line protection.

  In an SDH / SONET (Synchronous Digital Hierarchy / Synchronous Optical Network) transmission system, 1 + 1 bidirectional line protection or 1 + 1 is used as a line protection for maintenance when a failure occurs in the network. Unidirectional line protection is standardized. Here, 1 + 1 bidirectional line protection is a method of simultaneously switching the receiving side of a bidirectional line with respect to a fault that has occurred in a line. 1 + 1 unidirectional line protection detects a fault with respect to a fault that has occurred in a line. This is a method of switching only the receiving side in the station. These two line protections are, for example, ITU-T (International Telecommunications Union-Telecommunications Standardization Sector). 783 Annex A, Annex B or Bellcore GR-253-CORE.

  In 1 + 1 bidirectional line protection and 1 + 1 unidirectional line protection, protection control is performed using K1 bytes and K2 bytes that constitute APS (Automatic Protection Switching) bytes placed in SOH (Section Over Head) in the transmission frame. It is carried out. Specifically, in the case of 1 + 1 bidirectional line protection, 1 to 4 bits of the K1 byte and K2 byte are used to convey information such as a failure occurrence status and a switch request by a command to the other party for protection. Control is performed. In the case of 1 + 1 one-way line protection, the protection is controlled using the failure information detected by the own station and the switching request given by the own station.

  By the way, when a failure occurs in a signal transmission line, it is usually performed to replace the interface circuit of the line in which the failure has occurred. In SDH / SONET, a transmission circuit and a reception circuit as interface circuits are often mounted on the same substrate. Therefore, when replacing the interface circuit of the line in which the failure has occurred, 1 + 1 bidirectional line protection in which the transmission circuit and the reception circuit are switched at the same time is more convenient. In the case of 1 + 1 bidirectional line protection, a switching test (EXERCISE) using an APS byte is supported, but in the case of 1 + 1 unidirectional line protection, this function is not supported. For this reason, the currently used line protection has a higher proportion of 1 + 1 bidirectional line protection.

  FIG. 20 shows a configuration of a conventionally proposed 1 + 1 bidirectional line protection control system (see, for example, Patent Document 1). In this figure, the left side is A station 101A, and the right side is B station 101B. Between the work (work) side interface (IF) units 111A and 111B of these stations 101A and 101B, work side main signal lines 112 and 113 are arranged one by one in both directions. Also, between the protect (protect) side interface (IF) units 114A and 114B, protect side main signal lines 115 and 116 are arranged one by one in both directions.

  The A station 101A is provided with a switch unit 117A for switching lines, a protection operation control unit 118A for performing protection control when a failure occurs, and an APS byte processing unit 119A for processing APS bytes. Similarly, the B station 101B is also provided with a switch unit 117B, a protection operation control unit 118B, and an APS byte processing unit 119B.

  In the conventionally proposed 1 + 1 bidirectional line protection system 100 having such a configuration, by using the APS bytes (K1, K2 bytes) 121, 122 included in the overhead of the main signal, the switch unit 117A of the own station, The switching state of 117B and the contents of failure when a failure occurs in any of the lines 112, 113, 115, 116 are transmitted to the game.

  In the 1 + 1 bidirectional line protection system 100, when no failure has occurred, the signal transmitted from the station A 101A is transmitted through the current work side main signal line 112, reaches the station B 101B, and is selected by the switch unit 117B. Is done. At this time, the contact piece of the reception signal switching unit 124B as the switch of the switch unit 117B is in a connection state opposite to the state shown in FIG. The signal transmitted from the B station 101B is transmitted through the current work-side main signal line 113, reaches the A station 101A, and is selected by the switch unit 117A. At this time, the contact piece of the reception signal switching unit 124A of the switch unit 117A is also in a connection state opposite to the state shown in FIG. In the above state, the signals that have flowed through the protection main signal lines 115 and 116 for protection reach each other, but the switch units 117A and 117B do not select them.

  In this 1 + 1 bidirectional line protection system 100, for example, it is assumed that a failure 120 occurs in the work side main signal line 112. Then, the work side interface unit 111B of the receiving station B 101B detects that the signal has been disconnected due to the failure 120, and notifies the protection operation control unit 118B. Upon receiving this notification, the protection operation control unit 118B requests the APS byte processing unit 119B to perform processing for notifying that the failure 120 has occurred. Based on this request, the APS byte processing unit 119B sends the protection side interface unit 114B the APS byte 122 instructing the switching to the protection side main signal line 115 and the failure 120 in the work side main signal line 112. The data is sent to station A 101A via

  The protect side interface unit 114A of the station A 101A sends the received APS byte 122 to the APS byte processing unit 119A. The APS byte processing unit 119A analyzes the received APS byte 122 and sends a channel switching request and an APS byte 121 indicating the line 112 to be switched to the station B 101B via the protect side interface unit 114A. Send it out.

  The B station 101B sends the received APS byte 121 to the APS byte processing unit 119B. The APS byte processing unit 119B sends the APS byte 121 to the protection operation control unit 118B for analysis. The protection operation control unit 118B determines that the work-side main signal lines 112 to be switched coincide with each other in the A station 101A and the B station 101B, and a built-in reception signal switching unit for the switch unit 117B. A switch unit switching control signal 131B for instructing switching of 124B is output. As a result, the contact of the reception signal switching unit 124B of the switch unit 117B is switched as illustrated.

  When the received signal switching unit 124B of the switch unit 117B is switched, the protection operation control unit 118B instructs the APS byte processing unit 119B to send the APS byte 122 indicating the switched work-side main signal line 112 to the A station 101A. Send it out. When the APS byte 122 is received by the A station 101A, the APS byte 122 is transmitted to the protection operation control unit 118A via the APS byte processing unit 119A, and is analyzed. As a result, since the work-side main signal lines 112 to be switched coincide with each other in the A station 101A and the B station 101B, the protection operation control unit 118A outputs the switch unit switching control signal 131A to output the switch unit 117A. The received signal switching unit 124A is switched.

In this way, both the reception signal switching units 124A and 124B of the switch units 117A and 117B are switched as shown in FIG. 20, and the signal transmission using the work side main signal lines 112 and 113 is changed to the protection side main signal. This means that the transmission path has been switched to signal transmission using the signal lines 115 and 116. In this state, the communication operation starts.
JP 09-074412 (paragraphs 0067 to 0071, FIG. 9)

  However, in this conventionally proposed 1 + 1 bidirectional line protection system 100, if a failure occurs in either the protection operation control unit 118A or the APS byte processing unit 119A of the station A 101A, the APS bytes 121 and 122 as described above are used. There was a problem that protection control using was not possible.

  This problem will be described with reference to FIG. In this figure, the same parts as those in FIG. 20 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. It is assumed that a failure 141 occurs in the protection operation control unit 118A or the APS byte processing unit 119A of the station A 101A at a certain time. In this state, it is assumed that a failure 120 occurs in the work side main signal line 112. Based on the occurrence of the failure 120, as described above, the APS byte 122 instructing switching to the protect main signal line 115 is transmitted from the B station 101B to the A station 101A.

  However, in this case, the failure 141 occurs in the protection operation control unit 118A or the APS byte processing unit 119A. Therefore, even if the APS byte 121 indicating the line 112 to be switched and the channel switching request is transmitted from the B station 101B that detects the failure 120 to the A station 101A, the protection operation control unit 118A or the APS byte processing unit 119A This is not handled due to the failure 141. Accordingly, in the A station 101A, the protection operation control unit 118A cannot send a channel switching request and an APS byte 121 (not shown) indicating the line 112 to be switched to the B station 101B side.

  As a result, the B station 101B cannot confirm that the work-side main signal line 112 to be switched is identical between the A station 101A and the B station 101B, and the switch as shown in FIG. The part switching control signal 131B is not output. That is, when the failure 141 illustrated in FIG. 21 occurs, the reception signal switching unit 124B is not switched and remains in the state illustrated in FIG. Therefore, the APS byte 122 for switching the received signal switching unit 124A of the switch unit 117A is not sent from the B station 101B side to the A station 101A, and the received signal switching unit on the A station 101A side. Switching of 124A is not performed.

  The case where the failure 141 occurs in either the protection operation control unit 118A or the APS byte processing unit 119A of the station A 101A has been described above. However, the failure 141 occurs in both the protection operation control unit 118A and the APS byte processing unit 119A. In this case, the same result is obtained. Similarly, when a failure occurs in the protection operation control unit 118B or the APS byte processing unit 119B of the station B 101B, the reception signal switching unit 124A and the reception signal switching unit 124B are not switched.

  As described above, according to the conventional proposal, when one of the protection operation control units 118A and 118B or the APS byte processing units 119A and 119B fails, and one end of the 1 + 1 bidirectional line protection system 100 does not function, the APS byte 121 is used. , 122 cannot be used for protection control. For this reason, 1 + 1 bidirectional line protection cannot be operated. That is, in this case, the reception signal switching units 124A and 124B cannot switch from the line in which the failure 120 has occurred to the backup side line, and the signal is cut off.

  Therefore, conventionally, when such a situation occurs, the contacts of the reception signal switching units 124A and 124B are manually switched. For this reason, it is necessary not only to increase the time until the communication operation is resumed, but also to secure personnel to deal with when the failure 120 occurs.

  As described above, it has been explained that the manual operation is necessary for the control of the two stations facing each other when a failure occurs in the work side main signal line 112 (113). Even if the initial setting of these two opposing stations is “bidirectional” or “one-way” line protection mode, even if an initial setting error has been made, it is conventionally necessary to manually match these modes. There was a problem that there was.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a communication device, a line protection control system, and a line protection control method capable of avoiding a failure that could not be avoided by line protection such as 1 + 1 bidirectional line protection without human intervention. is there.

  Another object of the present invention is to provide a communication device, a line protection control system, and a line protection control method capable of matching line protection modes between devices facing each other.

In the present invention, (a) a pair of working signal lines connecting with other stations arranged opposite to each other, and (b) a pair of standby signal lines connecting between the other stations described above, (C) switch means for switching between the pair of working signal lines and the pair of standby signal lines, and (d) a transmission frame transmitted through the working signal line from the other station. An APS (Automatic Protection Switching) byte placed in the SOH (Section OverHead) is input to perform processing based on this, and indicates a “bidirectional” mode in which the signal lines are switched at the same time when a failure occurs. APS byte processing means for processing to transmit an APS byte composed of a code to other stations as described above, and (e) APS byte processing fault detecting means for detecting a fault of this APS byte processing means; , (F) When the APS byte processing failure detection means detects a failure and the own station is in the “bidirectional” mode, the station that has detected the failure switches only the receiving side to “one-way” And the other station transition request means in the event of a failure, which transmits the transmission frame to the other station described above with the above-described APS byte as the code content for requesting the transition to the “one-way” mode, ) When the above-mentioned APS byte having the code content for requesting the transition to the “one-way” mode is sent from the other station, the own station is changed to the “one-way” mode and the own station “ APS byte changing means upon receiving a transition request for transmitting a transmission frame to the other station by incorporating an APS byte having a code content indicating that the mode is "one-way", and (h) detecting the APS byte processing failure described above When the stage no longer detects a fault, it changes its own station from the “one-way” mode to the “bi-directional” mode, and the APS with the code content indicating that the APS byte is the “bi-directional” mode. APS byte changing means at the time of restoration of the own station that transmits a transmission frame to the above-mentioned other station by incorporating a byte, and (ii) the above described after changing to the “bidirectional” mode by the APS byte changing means at the time of restoration of the own station When a transmission frame incorporating an APS byte having a code content indicating that it is in a “one-way” mode is sent from another station, the code content requesting a transition to the “bidirectional” mode is set to the above-mentioned other In the code that requests the transition to the "bidirectional" mode by the partner station transition request means at the time of failure recovery that transmits the transmission frame to the station, and (n) When the transmission frame is sent from another station as described above, the bidirectional mode recovery means for changing the local station to the “bidirectional” mode, and (le) the local station when the local station is in the “one-way” mode. The switching means executes the switching between the pair of working signal lines and the pair of standby signal lines described above only by the failure information detected by the station and the switching request given by the station. When the communication device is in the “bidirectional” mode, the communication device includes a switch control means for synchronizing the other station and executing the switching between the pair of working signal lines and the pair of standby signal lines. It has.

In the present invention, (a) a pair of working system signal lines connecting the first station and the second station arranged opposite to each other, and (b) the first station and the second station described above. A pair of standby signal lines connecting between the two, and (c) first station switch means for switching on the first station side between the pair of working signal lines and the pair of standby signal lines. (D) second station switch means for switching the pair of active signal lines and the pair of standby signal lines on the second station side; and (e) the first station described above. Based on this, an APS (Automatic Protection Switching) byte is placed in the SOH (Section OverHead) in the transmission frame transmitted from the second station and transmitted through the working signal line from the second station. Performs processing and simultaneously switches both directions of the signal line when a failure occurs First station-side APS byte processing means for processing so that an APS byte composed of a code indicating a “bidirectional” mode is initially transmitted to the second station; The APS byte in the SOH in the transmission frame transmitted from the first station and transmitted through the working signal line from the first station is input to perform the processing based on this, and “bidirectional” A second station-side APS byte processing means for processing to initially transmit an APS byte composed of a code indicating the mode to the first station, and (g) disposed in the first station, First station-side APS byte processing failure detection means for detecting a failure of the first station-side APS byte processing means, and (h) the second station-side APS arranged in the second station as described above. Second to detect failure of byte processing means The station-side APS byte processing failure detection means and (i) when the first station-side APS byte processing failure detection means is located in the first station and detects the failure, the first station side ”Mode is changed to“ one-way ”mode, and the above-described APS byte is transmitted to the above-mentioned second station with the code content requesting transition to the“ one-way ”mode. The first station side failure request means at the time of failure occurrence, which transmits a frame, and (n) the second station side APS byte processing failure detection means arranged at the second station described above detects a failure. When the second station is in the “bidirectional” mode, this is changed to the “one-way” mode, and the above-described APS byte is changed to the code content for requesting the transition to the “one-way” mode. To the first station A second station side partner station transition request means for transmitting a frame, and (l) arranged in the first station, and requests a transition from the second station to the “one-way” mode. When the APS byte having the code content is sent, the first station is changed to the “one-way” mode, and the APS byte having the code content indicating that the own station is in the “one-way” mode. A first station-side transition request receiving APS byte changing means for transmitting a transmission frame to the second station incorporated therein, and (e) disposed in the second station described above, When the above-mentioned APS byte with the code content requesting the transition to the “one-way” mode is sent, the second station is changed to the “one-way” mode and the own station is set to the “one-way” mode. Incorporating an APS byte with code content to indicate that Second station side transition request receiving APS byte changing means for transmitting a transmission frame to the first station, and (a) the first station side APS byte processing failure arranged at the first station. When the detection means no longer detects a failure, the first station side is changed from the “one-way” mode to the “bi-directional” mode, and the APS byte described above indicates the “bi-directional” mode. A first station restoration APS byte changing means for incorporating the APS byte of the code contents and transmitting the transmission frame to the second station, and (f) the second station, which is arranged in the second station, When the station side APS byte processing failure detection means no longer detects a failure, the second station side is changed from the “one-way” mode to the “bidirectional” mode, and the above-mentioned APS byte is set to “bidirectional”. Indicates mode Second station restoration APS byte changing means for transmitting a transmission frame to the first station by incorporating the APS byte of the code content, and (y) the first station arranged at the first station, When the station is restored, the APS byte changing means changes the mode to the “bidirectional” mode, and then the second station sends a transmission frame incorporating the APS byte having the code content indicating that the mode is the “one-way” mode. A first station side failure recovery partner station transition requesting means for transmitting a transmission frame to the second station described above with a code content for requesting transition to the “bidirectional” mode; A code that is arranged in the second station and indicates that it is in the “one-way” mode from the first station after being changed to the “bidirectional” mode by the APS byte changing means when the second station is restored. Content A When the transmission frame incorporating the S byte is sent, the other station at the time of failure recovery at the second station side which transmits the transmission frame to the first station described above with the code content requesting the transition to the “bidirectional” mode A transmission frame having a code content arranged in the first station and requesting a transition to the “bidirectional” mode by the second station side failure recovery requesting means at the time of recovery from the second station side. Is sent from the second station described above, the first station side bidirectional mode recovery means for changing the first station to the "bidirectional" mode, and (so) arranged in the second station described above When a transmission frame having a code content requesting the transition to the “bidirectional” mode is sent from the first station by the partner station transition requesting means at the time of the first station-side failure recovery, the second station Change the station to “bidirectional” mode Station-side bidirectional mode recovery means, and (ii) Fault information detected by the own station when the own station is in the “one-way” mode and the switching request given by the own station. The first station switch means simply switches between the pair of working signal lines and the pair of standby signal lines, while the local station is in the “bidirectional” mode. First station switch control means for executing switching between the pair of active signal lines and the pair of standby signal lines in synchronization with the second station, and (e) the second The above-mentioned second station switch means described above only by the failure information detected by the own station and the switching request given by the own station when the own station is in the “one-way” mode. Switching between a pair of active signal lines and a pair of standby signal lines On the other hand, when the own station is in the “bidirectional” mode, the first station is synchronized with the first station and the switching between the pair of working signal lines and the pair of standby signal lines is performed. The line protection control system includes two station switch control means.

Further, according to the present invention, (a) an APS (Automatic Protection Switching) byte arranged in an SOH (Section OverHead) in a transmission frame transmitted from the other station arranged opposite to the own station through the working signal line is provided. Input and perform processing based on this, and at the same time, transmit an APS byte composed of a code indicating a “bidirectional” mode that simultaneously switches the bidirectional of the signal line when a failure occurs to the other station described above. An APS byte processing fault detection step for detecting a fault with respect to the APS byte processing means to be processed at the same time, and (b) when the own station detects a fault with respect to the APS byte processing means in the APS byte processing fault detection step, When it is in the “bidirectional” mode, this is changed to the “one-way” mode in which only the receiving side is switched at the station where the failure is detected, A failure requesting partner station transition requesting step of transmitting the transmission frame to the other station as described above with the code content for requesting the transition to the “one-way” mode as described above, and (c) from the other station as described above When the above-described APS byte having the code content requesting the transition to the “one-way” mode is sent, the own station is changed to the “one-way” mode and the own station is in the “one-way” mode. An APS byte change step upon receiving a transition request for transmitting a transmission frame to the other station by incorporating an APS byte having a code content indicating that, and (d) the APS byte processing means described above in the APS byte processing failure detection step When no fault is detected, the own station is changed from the “one-way” mode to the “bi-directional” mode, and the above-described APS byte is set to the “bi-directional” mode. A self-station recovery APS byte changing step of incorporating the APS byte of the code content indicating the presence and transmitting the transmission frame to the other station as described above; When the transmission frame incorporating the APS byte with the code content indicating the “one-way” mode is sent from the above-mentioned other station after the mode is changed to the mode, the transition to the “bi-directional” mode is requested. Code for requesting transition to the “bidirectional” mode by the fault recovery partner station transition request step for transmitting the transmission frame to the other station as described above and (f) this fault recovery partner station transition request step A bidirectional mode recovery step of changing the local station to the “bidirectional” mode when a transmission frame of contents is sent from another station as described above; When the station is in the “one-way” mode, only a pair of current connections between the own station and the above-mentioned other stations with respect to a predetermined switch means only by the failure information detected by the own station and the switching request given by the own station While switching the system signal line and the pair of standby system signal lines, when the own station is in the “bidirectional” mode, the above-mentioned pair of working system signal lines The line protection control method includes a switch control step for switching a pair of standby signal lines.

As described above, according to the present invention, automatic switching of the protection mode is realized against the occurrence of a failure by adopting a method of adding information related to state transition to information transmitted to the other device such as an APS byte. be able to. Therefore, even if the occurrence of a failure in the line and the occurrence of a failure in the communication device occur, it is possible to prevent the interruption of the signal transmitted between the devices as much as possible.

  Further, in the present invention, even if there is an initial mistake regarding the mode setting of each communication device, this can be correctly set to a predetermined mode. Therefore, it is possible to omit the manual mode setting.

  Hereinafter, the present invention will be described in detail with reference to examples.

  FIG. 1 shows a station constituting a line protection control system according to the first embodiment of the present invention. Here, the configuration of the A station 201A as one of the stations constituting the system is shown. The B station 201B described later has the same circuit configuration, but it is necessary to distinguish both for the sake of explanation. Therefore, the symbol “A” is appended to the end of the numbers representing the circuit components constituting the A station 201A. For the B station 201B not shown in FIG. 1, the symbol “B” is used instead of the symbol “A”. ".

  The A station 201A constituting the line protection control system of the first embodiment is connected between the work side interface (IF) unit 211A and the work side interface circuit of the opposite station (B station 201B) (not shown). The workpiece side main signal lines 212 (transmission direction) and 213 (reception direction) are connected. In addition, two protect main signal lines 215 (transmission direction) and 216 (reception) are provided between the protect (protection) side interface (IF) unit 214A and the protection side interface circuit of the opposite station (B station 201B) (not shown). Direction).

  The A station 201A is provided with a switch unit 217A that performs line switching, a protection operation control unit 218A that performs protection control when a failure occurs, and an APS byte processing unit 219A that performs APS byte processing. Further, the A station 201A of the first embodiment has an APS byte process monitoring unit 221A, a fixed APS byte insertion circuit 222A, a fixed protection control instruction circuit 223A, a selector, as compared with the conventional A station 101A shown in FIG. 224A and a selector instruction circuit 225A are newly added.

  In the A station 201A, as a circuit conventionally provided, an APS byte transmission circuit 231A is arranged on the side of the APS byte processing unit 219A opposite to the selector 224A, and a protection side interface unit 214A in the APS byte processing unit 219A is provided. An APS byte receiving circuit 232A is arranged on the opposite side. Further, as a circuit provided conventionally, a work-side interface reception alarm transmission circuit 233A is arranged on the side facing the protection operation control unit 218A in the work-side interface unit 211A, and a protection operation control unit 218A in the protect-side interface unit 214A. Protect side interface reception alarm transmission circuit 234A is arranged on the side opposite to.

  Here, the APS byte processing unit 219A terminates the APS bytes (K1, K2 bytes) extracted from the SDH / SONET signals received by the work side interface unit 211A and the protect side interface unit 214A. Then, the switching request on the opposite side (B station 201B) and the failure occurrence state are recognized, and an instruction for the switching state of protection for the own station is transmitted to the protection operation control unit 218A. In addition, when the APS byte processing unit 219A detects a failure of the protection operation control unit 218A, it transmits a “UNI transition” code from 6 to 8 bits in K2 of the APS byte through the APS byte transmission circuit 231A. Yes.

  The APS byte processing monitoring unit 221A monitors the state of the APS byte processing unit 219A. When the APS byte processing unit 219A cannot receive or transmit the APS byte, or when the APS byte processing unit 219A itself is in an abnormal state such as a freeze state, this is detected. Then, the APS byte process monitoring unit 221A inserts a value indicating “normal switching state” into the APS byte transmission circuit 231A as a fixed value through the fixed APS byte insertion circuit 222A for 1 to 4 bits of the K1 byte and the K2 byte. , “010 (one-way transition)” is similarly inserted into the APS byte transmission circuit 231A for 6 to 8 bits of the K2 byte.

  In addition, when the APS byte processing monitoring unit 221A enters this abnormal state, the APS byte processing monitoring unit 221A sends a signal indicating an instruction to change to the 1 + 1 unidirectional line protection to the protection operation control unit 218A through the fixed protection control instruction circuit 223A. It comes to supply. In the first embodiment, this failure is temporarily dealt with by automatically changing to 1 + 1 one-way line protection when a predetermined failure occurs. They are exchanged to shift to 1 + 1 bidirectional line protection.

  The switch unit 217A includes a transmission signal branching unit 241A for branching a signal to be transmitted into the work side main signal line 212 and the protection side main signal line 215, and sending the signal to the opposite side, the work side main signal line 213, and the protection side main signal. The reception signal switching unit 242A is configured as a switch for selecting one of the reception signals transmitted from the B station 201B (not shown) which is the opposite station via the line 216. The configuration itself of such a switch unit 217A is the same as the conventional one.

  The main circuit parts such as the work side interface unit 211A, the protect side interface unit 214A, the protection operation control unit 218A, the APS byte processing unit 219A, and the APS byte processing monitoring unit 221A shown in FIG. (Central Processing Unit) is provided, and predetermined control is performed by executing a control program stored in a storage medium (not shown). The A station 201A is also provided with a CPU for overall control, and unified control as the A station 201A is performed.

  FIG. 2 shows an outline of the configuration of the line protection control system in the first embodiment. In this line protection control system 200, signals are transmitted and received between the A station 201A and the B station 201B. The configuration of the A station 201A is shown more simplified than that in FIG. The same applies to the configuration of the B station 201B.

  FIG. 2 shows a normal state of the 1 + 1 bidirectional line protection in which no failure has occurred in the transmission path. In this state, the protection operation control units 218A and 218B of both the A station 201A and the B station 201B operate with bidirectional line protection. At this time, the APS byte processing units 219A and 219B transmit the APS bytes in which 6 to 8 bits of K2 are configured by a code indicating “bidirectional” to each other.

  In this normal state, the signal transmitted from the A station 201A reaches the switch unit 217B of the B station 201B using the work side main signal line 212 as the active system and the protect side main signal line 215 as the standby system, Here, the signal of the work side main signal line 212 is selected. The signal transmitted from the B station 201B reaches the switch unit 217A of the A station 201A using the work side main signal line 213 as the active system and the protect side main signal line 216 as the standby system. The signal on the main signal line 213 is selected.

  By the way, in the first embodiment, two new “010 (one-way transition)” and “011 (bidirectional transition)” are newly defined for 6 to 8 bits of the K2 byte of the APS byte. ing. The conventional codes “101 (bidirectional)” and “100 (one direction)” indicate the 1 + 1 line protection mode in which the local station operates, and telling the other party that both are in the same mode. It is a code only for confirmation.

  The “010 (one-way transition)” code newly defined in the first embodiment is a code requesting that the partner station transition to 1 + 1 one-way line protection. When the other station is in the 1 + 1 one-way line protection mode and the own station is in the 1 + 1 bidirectional line protection mode, the modes do not match and the system does not operate. The “011 (bidirectional transition)” code is a code for making a request to shift the 1 + 1 line protection mode of the partner station to 1 + 1 bidirectional line protection.

  In the line protection control system 200 according to the first embodiment, these two newly added codes “010 (one-way transition)” and “011 (bidirectional transition)” and the two codes “ By combining “101 (bidirectional)” and “100 (one direction)”, an automatic switching sequence of the protection mode is realized.

  FIG. 3 shows the processing operation of the APS byte processing unit of the first embodiment. The two APS byte processing units 219A and 219B in FIG. 2 both have the tables 245A and 245B shown in FIG. 3, and the APS byte processing is performed based on the tables. In the table 245A (245B), “APS byte issued by itself” refers to the APS byte sent to the B station 201B by the processing of the APS byte processing unit 219A, for example, when the A station 201A is the own station. In this example, the “APS byte” means an APS byte transmitted from the B station 201B to the A station 201A. In this example, the “operation mode” is a mode after the change of the A station 201A by the APS byte sent from the partner B station 201B. The “transmission APS” means that the A station 201A An APS byte to be transmitted to 201B. For example, when the A station 201A receives an APS byte representing "one-way" from the station B 201B during transmission of an APS byte representing "bidirectional transition", the A station 201A changes its protection mode to "one-way". At the same time, the APS byte of “bidirectional transition” is transmitted to the B station 201B.

  FIG. 4 shows the relationship between the change in the APS byte sent from the A station and the B station and the protection mode. This will be described with reference to FIGS. In the line protection control system 200 of the first embodiment, the A station 201A and the B station 201B are in the 1 + 1 bi-directional line protection mode without any failure. In this situation, as shown in the section 301 of FIG. 4, the A station 201A and the B station 201B set the APS byte of “101 (bidirectional)” which is the current state of the own station while keeping a predetermined time from each other. K1, K2 bytes) 251 and 252 are transmitted.

  In this normal state, the APS byte 251 representing “bidirectional” is transmitted from the A station 201A to the B station 201B. When the APS byte processing unit 219B of the B station 201B receives the APS byte 251 indicating “bidirectional”, the current B station 201B is also in the “bidirectional” mode, and therefore, the table 245A (245B) in FIG. As described above, the “bidirectional” mode is maintained, and the APS byte 252 representing “bidirectional” is transmitted. The same process is performed when the APS byte 252 representing “bidirectional” is sent from the B station 201B to the A station 201A. In this way, the A station 201A and the B station 201B hold the 1 + 1 bidirectional line protection mode while periodically outputting the APS bytes 251 and 252 until a failure occurs.

  <Operation when a failure occurs in the APS byte processing unit>

  FIG. 5 shows a case where a failure has occurred in the APS byte processing unit of the B station. First, the operation of the line protection control system 200 when a failure 311 occurs in the APS byte processing unit 219B will be described. When a failure 311 occurs in the APS byte processing unit 219B, the APS byte processing monitoring unit 221B detects this. As this detection technique, various known techniques relating to fault detection can be used. For example, the APS byte processing unit 219B sends a signal indicating normality to the APS byte processing monitoring unit 221B at regular intervals, and the failure 311 occurs when this signal is not received. You may make it detect. On the contrary, the APS byte processing monitoring unit 221B makes an inquiry to the APS byte processing unit 219B at intervals, checks the presence / absence of the response or the content of the response, and a fault 311 occurs in the APS byte processing unit 219B. It is also possible to detect whether or not

  When the APS byte processing monitoring unit 221B detects the failure 311 of the APS byte processing unit 219B, the protection operation control unit 218B is changed from the “bidirectional” mode immediately before to the “one-way” mode. Further, the APS byte processing monitoring unit 221B causes the “010 (one-way transition)” code to be output from the fixed APS byte insertion circuit 222B to the selector 224B, and this “010 (one-way transition)” code is output according to an instruction from the selector instruction circuit 225B. The APS byte 252 using is output from the selector 224B. The APS byte 252 is sent from the protect-side interface unit 214B to the A station 201A.

  At this time, the protection operation control unit 218A of the station A 201A still maintains the “bidirectional” mode. Therefore, in this state, the APS byte 251 of “101 (bidirectional)” is still output from the A station 201A to the B station 201B.

  When the APS byte 252 of “010 (one-way transition)” is output from the B station 201B at the start of the section 302 in FIG. 4, this is sent to the APS byte processing unit 219A via the protect side interface unit 214A of the A station 201A. To reach. The APS byte processing unit 219A changes the A station 201A to the “one-way” mode because the APS byte issued by the own station is “bidirectional” and the APS byte coming from the partner is “one-way transition”. Upon completion of the mode switching, the A station 201A inserts (overwrites) a “100 (one-way)” code in K2 and 6 bits of the APS byte 251. Then, the changed APS byte 251 is sent to the B station 201B. The APS byte 251 reaches the APS byte processing unit 219B of the B station 201B, but the APS byte processing unit 219 does not operate because it has caused the failure 311. In this way, automatic switching to 1 + 1 one-way line protection is completed.

  FIG. 6 shows a state in the latter half of the section 302 shown in FIG. The APS byte 251 of “100 (one direction)” is output from the A station 201A, and the APS byte 252 of “010 (unidirectional transition)” is output from the B station 201B. In this state, not only the protection operation control unit 218B of the B station 201B but also the protection operation control unit 218A of the A station 201A is set to the “one-way” mode.

  In the state of FIG. 6, since the protection operation control units 218A and 218B are operating in one-way line protection, the APS byte processing units 219A and 219B are used when a failure occurs on the work side lines 212 and 213. Without switching to the protection side lines 215, 216. Therefore, both in the case where a failure occurs in the line in the direction from the B station 201B to the A station 201A and in the case where a failure occurs in the line in the direction from the A station 201A to the B station 201B, the signal can be relieved by protection control. it can.

  FIG. 7 shows the operation of the line protection control system when a failure occurring in the station B is recovered. As shown in FIG. 7, when the failure 311 is recovered, the APS byte process monitoring unit 221B detects this. This detection can be performed in the same manner as the detection operation of the occurrence of the failure 311. At this stage, the APS byte process monitoring unit 221B stops the signal supplied to the fixed APS byte insertion circuit 222B and the fixed protection control instruction circuit 223B.

  On the other hand, the APS byte processing unit 219B starts to operate with the operation before the occurrence of the failure as the failure 311 is recovered. When the failure 311 is recovered, the APS byte processing unit 219B supplies a signal for instructing the protection operation control unit 218B to operate in bidirectional line protection. When the mode switching from “one-way” to “bi-directional” is completed in the protection operation control unit 218B, the protection operation control unit 218B supplies a switch completion notification to the APS byte processing unit 219B.

  In response to the notification of switching completion, the APS byte processing unit 219B inserts (overwrites) the “101 (bidirectional)” code in the APS byte 252 and transmits it from the APS byte transmission circuit 231B to the A station 201A. At this time, the A station 201A remains in the “one-way” mode. Therefore, as shown in FIG. 7, the line protection mode of station A and the line protection mode of station B are in conflict.

  FIG. 8 shows the operation of the system when an APS byte representing a different mode arrives from the A station after the failure is recovered and the mode of the B station is switched. As described above, since the A station 201A remains in the “one-way” mode, the APS byte processing unit 219B of the B station 201B uses the APS byte 251 to “100 (one-way) as shown in the second half of the section 302 in FIG. Will be given the code. Then, the APS byte processing unit 219B changes to insert (overwrite) the “011 (bidirectional transition)” code based on the difference in the line protection mode. Thereby, as shown in the first half of the section 303, the APS byte 252 of “011 (bidirectional transition)” is transmitted from the B station 201B to the A station 201A.

  As a result, the APS byte processing unit 219A of the A station 201A is given a “011 (bidirectional transition)” code from the B station 201B. In the APS byte processing unit 219A, the operation mode is switched from “one-way” to “bi-directional” according to the table 245A (245B) of FIG. Based on this, the APS byte processing unit 219A supplies a signal instructing the protection operation control unit 218A to operate in the bidirectional line protection. When the protection operation control unit 218A completes the mode switching based on this instruction, a switching completion notification is supplied to the APS byte processing unit 219A. Based on this, the APS byte processing unit 219A inserts (overwrites) the “101 (bidirectional)” code in the APS byte 251 and sends it to the B station 201B. The second half of the section 303 in FIG. 4 shows how the APS byte 251 is transmitted from the A station 201A to the B station 201B.

  FIG. 9 shows the operation of the line protection control system when the “011 (bidirectional transition)” code is given to the A station. At the stage where the APS byte processing unit 219B sends the APS byte 252 of the “011 (bidirectional transition)” code, the B station 201B has the APS byte 251 in which the “101 (bidirectional)” code is inserted in the above-described processing. Receive. Based on this, the APS byte processing unit 219B supplies a signal for instructing the protection operation control unit 218B to operate in bidirectional line protection.

  The protection operation control unit 218B is already operating in both directions. Therefore, upon receiving this instruction from the APS byte processing unit 219B, it can be determined that the “bidirectional transition” instruction has been transmitted to the A station 201A, and a switch completion notification is sent to the APS byte processing unit 219B. Upon receiving this switching completion notification, the APS byte processing unit 219B determines that it is no longer necessary to send the “011 (bidirectional transition)” code as the APS byte 252. Thereafter, as shown in FIG. A “101 (bidirectional)” code is inserted (overwritten) in 252. In this state, automatic switching to 1 + 1 bidirectional line protection is completed. A section 304 in FIG. 4 represents the transmission of the APS byte 252 of the B station 201B.

  Thereafter, as long as no failure occurs, the A station 201A and the B station 201B, as indicated by the section 305 or the section 301 in FIG. The byte 251 or the APS byte 252 is periodically transmitted.

  <Operation when a failure occurs in the protection operation control unit>

  Next, the operation of the line protection control system 200 when a failure occurs in the protection operation control unit 218B will be described. The line protection control system 200 before a failure occurs in the protection operation control unit 218B is in a normal state operation of the 1 + 1 bidirectional line protection shown in FIG. At this time, the APS byte processing units 219A and 219B transmit the APS bytes in which 6 to 8 bits of K2 are configured by a code indicating “bidirectional” (see section 301 in FIG. 4).

  FIG. 10 shows a situation in which a failure has occurred in the protection operation control unit of the B station. When a failure 321 occurs in the protection operation control unit 218B, the APS byte processing unit 219B detects this. A known method can be used to detect the failure 321. The APS byte processing unit 219B supplies a “010 (one-way transition)” code to the APS byte transmission circuit 231B based on the detection result.

  As a result, the APS byte 252 of “010 (one-way transition)” is transmitted from the B station 201B to the A station 201A as shown in the first half of the section 302 in FIG. At this time, the A station 201A transmits the “101 (bidirectional)” APS byte 251 to the B station 201B as before.

  FIG. 11 shows the operation of station A that has received the APS byte of “010 (one-way transition)”. When the APS byte processing unit 219A of the A station 201A is given the APS byte 252 of the “010 (one-way transition)” code from the B station 201B, the protection operation control unit 218A according to the table 245A (245B) shown in FIG. Is supplied with a signal instructing to operate with one-way line protection. The protection operation control unit 218A completes the switching of the mode to “one direction” according to this instruction, and sends a switching completion notification to the APS byte processing unit 219A.

  Upon receiving the switching completion notification, the APS byte processing unit 219A inserts (overwrites) a “100 (one-way)” code in the APS byte 251 and transmits it from the APS byte transmission circuit 231A to the B station 201B. This is as shown in the latter half of the section 302 in FIG.

  In the B station 201B, while the APS byte 252 of the “010 (one-way transition)” code is being transmitted from the APS byte processing unit 219B to the A station 201A, the APS byte of the “100 (one-way)” code is transmitted from the A station 201A. 251 is received. When the APS byte 252 of this “010 (one-way transition)” code is received from the A station 201A, the APS byte processing unit 219B sends a signal instructing the protection operation control unit 218B to operate in one-way line protection. To do. However, since the failure 321 has occurred in the protection operation control unit 218B, switching to the “one-way” mode is not completed by this instruction. Therefore, the APS byte 252 issued by the B station 201B remains the “010 (one-way transition)” code. That is, in this state, automatic switching to 1 + 1 one-way line protection is completed.

  In the situation shown in FIG. 11, only station A 201A operates with 1 + 1 one-way linear protection. Therefore, when a failure occurs in the line in the direction from the B station 201B to the A station 201A, the signal can be relieved by protection control. When a fault occurs in the line in the direction from the A station 201A to the B station 201B, which is opposite to this, a fault has occurred in the protection operation control unit 218B, and the transmitted signal cannot be relieved.

  FIG. 12 shows the operation of the line protection control system when the failure of the protection operation control unit of station B is recovered. As shown in FIG. 12, when the failure 321 is recovered, the protection operation control unit 218B can accept the unidirectional mode change instruction transmitted from the APS byte processing unit 219B from this time point. When the protection operation control unit 218B receives a mode change instruction in one direction, the protection operation control unit 218B changes from the “bidirectional” mode to the “one direction” mode. When the mode switching is thus completed, the protection operation control unit 218B outputs a switching completion notification to the APS byte processing unit 219B. Upon receiving the switching completion notification, the APS byte processing unit 219B inserts (overwrites) the “011 (bidirectional transition)” code in the APS byte 252 and transmits it from the APS byte transmission circuit 231B to the A station 201A. This corresponds to the first half of the section 303 in FIG.

  FIG. 13 shows the operation of the line protection control system when the “011 (bidirectional transition)” code is given to the A station. When the APS byte 252 in which the “011 (bidirectional transition)” code is inserted reaches the station A 201A, the APS byte processing unit 219A sends a signal instructing the protection operation control unit 218A to operate in the bidirectional line protection. Supply. Based on this, the protection operation control unit 218A completes the mode switching, and sends a switching completion notification to the APS byte processing unit 219A. Upon receiving the switching completion notification, the APS byte processing unit 219A inserts (overwrites) the “101 (bidirectional)” code in the APS byte 251 and transmits it from the APS byte transmission circuit 231A to the B station 201B. This corresponds to the latter half of the section 303 in FIG.

  FIG. 14 shows the operation of the line protection control system when the “101 (bidirectional)” code is given to the B station. The APS byte processing unit 219B of the B station 201B transmits the APS byte 252 in which the “011 (bidirectional transition)” code is inserted and the APS byte 251 in which the “101 (bidirectional)” code is inserted from the A station 201A. Receive. Then, the APS byte processing unit 219B supplies a signal instructing the protection operation control unit 218B to operate with bidirectional line protection.

  The protection operation control unit 218B switches from the “one-way” mode to the “bidirectional” mode based on this instruction. When this switching is completed, the protection operation control unit 218B sends a switching completion notification to the APS byte processing unit 219B. Upon receiving this switching completion notification, the APS byte processing unit 219B inserts (overwrites) the “101 (bidirectional)” code into the APS byte 252 and transmits it from the APS byte transmission circuit 231B to the A station 201A. This corresponds to the section 304 in FIG.

  At this point, automatic switching to 1 + 1 bidirectional line protection is complete. Thereafter, as long as no failure occurs, the A station 201A and the B station 201B, as indicated by the section 305 or the section 301 in FIG. The byte 251 or the APS byte 252 is periodically transmitted.

  According to the line protection control system 200 of the present embodiment described above, the APS byte is not used for the switching operation in the 1 + 1 one-way line protection. Then, protection is performed using only the failure information of the line detected by the own station and the protection control information of the command as a switching factor. For this reason, it is possible to implement protection only by the control of the own station without depending on the switching state of the game and the failure occurrence state.

  In this embodiment, when the 1 + 1 bidirectional line protection stops functioning, the protection mode is automatically changed to the 1 + 1 one-way line protection. As a result, when the failure of the line occurs when the protection operation control unit 218 or the APS byte processing unit 219 fails, the APS byte processing unit and the protection operation control unit fail. Line faults detected at stations that have not been repaired can be remedied by 1 + 1 one-way line protection.

  Here, the signals that can be relieved differ depending on the location of failure. When the protection operation control unit 218 fails, it is possible to rescue only a signal in a direction received by a node where no failure has occurred. Therefore, half of the entire signal can be relieved. When only the APS byte processing unit 219 fails, all line faults can be relieved by inserting an instruction that automatically becomes 1 + 1 one-way line protection into the protection operation control unit 218 within the own station. it can. That is, in this case, the entire signal can be relieved.

  When a failure occurs in the protection operation control unit 218 or the APS byte processing unit 219, it is possible to manually change from 1 + 1 bidirectional line protection to 1 + 1 unidirectional line protection. However, in the conventional system, it takes a long time from the failure detection to the protection mode change, and only the node in which no failure has occurred can be changed.

  FIG. 15 shows the stations constituting the line protection control system in the second embodiment of the present invention. Here, the configuration of the A station 401A as one of the stations constituting the system is shown. The B station 401B described later has the same circuit configuration. In FIG. 15, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. As can be seen from comparison with FIG. 1, the A station 401A of the second embodiment includes an APS byte process monitoring unit 221A, a fixed APS byte insertion circuit 222A, a fixed protection control instruction circuit 223A, a selector 224A, and a selector instruction circuit in FIG. 225A is deleted.

  FIG. 16 shows an outline of the configuration of the line protection control system in the second embodiment. In the line protection control system 400, signals are transmitted and received between the A station 201A and the B station 201B. The configuration of the A station 201A is shown more simplified than FIG. The same applies to the configuration of the B station 201B.

  By the way, in this line protection control system 400, when the “bidirectional” or “one-way” line protection mode to be initially set to coincide with each other is set incorrectly or when the setting itself is not performed. In addition, the mode can be automatically matched. In the present embodiment, a case will be described in which the mode is corrected to the 1 + 1 bidirectional line protection mode by automatic mode switching when the protection mode is erroneously set. In FIG. 16, the protection operation control unit 218A of the A station 401A is initially set to the “one-way” mode, and the protection operation control unit 218B of the B station 401B is initially set to the “bidirectional” mode. ing.

  Therefore, when the line protection control system 400 starts up, the APS byte 251 of “100 (one direction)” code is transmitted from the A station 401A to the B station 401B. Further, the APS byte 252 of the “101 (bidirectional)” code is transmitted from the B station 401B to the A station 401A.

  FIG. 17 shows the operation of the line protection control system when the APS byte processing unit of the B station is given a “100 (one-way)” code from the A station. The APS byte processing unit 219B of the B station 401B receives the APS byte 251 in which the “100 (one direction)” code is inserted (overwritten) from the A station 401A. Then, according to the table 245A (245B) shown in FIG. 3, since the own station is in the “bidirectional” mode and the other station is in the “one-way” mode, the own station is kept in the “bidirectional” mode, A code “011 (bidirectional transition)” is inserted (overwritten) in the APS byte 252. Therefore, at this point, the APS byte 251 of “100 (one direction)” code is transmitted from the A station 401A to the B station 401B, and “011 (bidirectional transition)” is transmitted from the B station 401B to the A station 401A. The APS byte 252 of the code will be sent out.

  FIG. 18 shows the operation of the line protection control system when the APS byte processing unit of the A station is given a “011 (bidirectional transition)” code from the B station. The APS byte processing unit 219A of the A station 401A receives the APS byte 252 of the “011 (bidirectional transition)” code from the B station 401B. Therefore, the APS byte processing unit 219A outputs a signal instructing the protection operation control unit 218A to operate with bidirectional line protection. Upon receiving this instruction, the protection operation control unit 218A switches to the “bidirectional” mode. When this switching is completed, the protection operation control unit 218A outputs a switching completion notification to the APS byte processing unit 219A.

  When the APS byte processing unit 219A receives the switching completion notification, the local station is in the “one-way” mode and the partner station is in the “bidirectional transition” mode based on the contents of the table 245A (245B) shown in FIG. Is changed to the “bidirectional” mode, and the “101 (bidirectional)” code is inserted (overwritten) in the APS byte 251 and transmitted to the B station 401B. Therefore, at this point, the APS byte 251 of the “101 (bidirectional)” code is transmitted from the A station 401A to the B station 401B, and “011 (bidirectional transition)” is transmitted from the B station 401B to the A station 401A. The APS byte 252 of the code will be sent out.

  FIG. 19 shows the operation of the line protection control system when station B subsequently receives a “101 (bidirectional)” code from station A. The APS byte processing unit 219B of the B station 401B inserts (overwrites) the “101 (bidirectional)” code from the A station 401A during transmission of the APS byte 252 in which the “011 (bidirectional transition)” code is inserted (overwritten). ) Received APS byte 251 is received. Then, the APS byte processing unit 219B outputs a signal instructing the protection operation control unit 218B to operate with bidirectional line protection.

  Here, the protection operation control unit 218B is already operating in the “bidirectional” mode at this point. Accordingly, the protection operation control unit 218B outputs a switch completion notification to the APS byte processing unit 219B. The APS byte processing unit 219B that has received this switching completion notification inserts (overwrites) the “101 (bidirectional)” code in the APS byte 252 and transmits the APS byte transmission circuit 231B to the A station 201A. This corresponds to the section 304 in FIG.

  At this point, automatic switching to 1 + 1 bidirectional line protection is complete. Thereafter, as long as no failure occurs, the A station 201A and the B station 201B, as indicated by the section 305 or the section 301 in FIG. The byte 251 or the APS byte 252 is periodically transmitted.

  In the second embodiment, as shown in FIG. 15, the configuration of each station such as the A station 401 </ b> A is simplified as compared with FIG. 1, but of course, the configuration may be the same as FIG. 1. In this case, as described in the first embodiment, it becomes possible to cope with various failures.

  In the first and second embodiments, the 1 + 1 bidirectional line protection and the 1 + 1 unidirectional line protection have been described. However, the active system line is “N” (N is an arbitrary integer equal to or greater than 1). The present invention can be similarly applied to 1 + N bidirectional line protection and 1 + N unidirectional line protection in which the line is “1”.

It is a block diagram of the A station which comprises the line protection control system in 1st Example of this invention. It is a system configuration figure of a line protection control system of the 1st example. It is explanatory drawing which shows the logic of the processing operation of the APS byte process part of a 1st Example. It is explanatory drawing showing the mode of change of the APS byte which A station and B station send out, and the relationship of protection mode in a 1st Example. It is explanatory drawing which showed the case where a failure generate | occur | produced in the APS byte process part of B station in 1st Example. It is explanatory drawing showing the state of the second half of the area 302 shown in FIG. 4 in 1st Example. It is explanatory drawing which shows operation | movement of a line protection control system when the failure which arose in the B station in the 1st Example was recovered. It is explanatory drawing which shows operation | movement when the APS byte showing the mode different from this comes from A station after the mode of B station was switched in the 1st Example. It is explanatory drawing which shows operation | movement when the "011 (bidirectional transition)" code | cord | chord is given to A station in the 1st Example. It is explanatory drawing which showed the condition where the failure generate | occur | produced in the protection operation control part of B station in 1st Example. It is explanatory drawing showing operation | movement of the A station which received the APS byte of "010 (one way transition)" in the 1st Example. It is explanatory drawing showing operation | movement at the time of the failure | restoration of the protection operation | movement control part of the B station recovering in the 1st Example. It is explanatory drawing showing operation | movement when the "011 (bidirectional transition)" code | cord | chord is given to A station in the 1st Example. It is explanatory drawing showing operation | movement when the "101 (bidirectional)" code | cord | chord is given to the B station in the 1st Example. It is a block diagram of the station which comprises the line protection control system in the 2nd example of the present invention. It is a system configuration figure of a line protection control system in the 2nd example. It is explanatory drawing which shows operation | movement when a "100 (one direction)" code | cord | chord is given to the B station in 2nd Example. It is explanatory drawing which shows operation | movement when the "011 (bidirectional transition)" code | cord | chord is given to the A station in 2nd Example. It is explanatory drawing which shows operation | movement when B station receives a "101 (bidirectional)" code | cord | chord in a 2nd Example. It is a system block diagram of the 1 + 1 bidirectional | two-way line protection control system proposed conventionally. It is a system block diagram for demonstrating the problem when a failure generate | occur | produces in the 1 + 1 bidirectional | two-way line protection system proposed conventionally.

Explanation of symbols

200, 400 Line protection control system 201A, 401A A station 201B, 401B B station 211A, 211B Work side interface circuit 212, 213 Work side main signal line 214A, 214B Protect side interface circuit 215, 216 Protect side main signal line 217A, 217B Switch unit 218A, 218B Protection operation control unit 219A, 219B APS byte processing unit 221A, 221B APS byte processing monitoring unit 222A, 222B Fixed APS byte insertion circuit 223A, 223B Fixed protection control instruction circuit 224A, 224B selector 242A, 242B Part 245A, 245B Table

Claims (10)

A pair of working signal lines connecting between other stations arranged opposite to each other;
A pair of standby signal lines connecting the other stations;
Switch means for switching between the pair of working signal lines and the pair of standby signal lines;
An APS (Automatic Protection Switching) byte arranged in an SOH (Section OverHead) in a transmission frame transmitted from the other station through the working signal line is input to perform processing based on this, and a failure occurs. APS byte processing means for processing to initially transmit an APS byte composed of a code indicating a “bidirectional” mode that simultaneously switches the bidirectional of the signal line to the other station;
APS byte processing fault detection means for detecting a fault in the APS byte processing means;
When this APS byte processing failure detection means detects a failure and the own station is in the “bidirectional” mode, this is changed to the “one-way” mode in which only the receiving side is switched at the station that detected the failure. And at the time of failure, a partner station transition request means for transmitting a transmission frame to the other station with a code content for requesting transition to the “one-way” mode of the APS byte,
When the APS byte having the code content requesting the transition to the “one-way” mode is sent from the other station, the own station is changed to the “one-way” mode and the own station is changed to the “one-way” mode. A transition request receiving APS byte changing unit that incorporates an APS byte having a code content indicating that the mode is a mode and transmits a transmission frame to the other station;
When the APS byte processing failure detection means no longer detects a failure, the own station is changed from the “one-way” mode to the “bidirectional” mode, and the APS byte is set to the “bidirectional” mode. APS byte changing means at the time of recovery from the own station, which incorporates an APS byte having the code content shown and transmits a transmission frame to the other station;
After changing to the “bidirectional” mode by the APS byte changing means at the time of restoration of the local station, a transmission frame incorporating an APS byte having a code content indicating the “one-way” mode is sent from the other station. A failure recovery partner station transition request means for transmitting a transmission frame to the other station in a code content requesting transition to a “bidirectional” mode,
When the transmission frame having the code content requesting the transition to the “bidirectional” mode is sent from the other station by the partner station transition requesting means at the time of failure recovery, both of the own stations are changed to the “bidirectional” mode. Direction mode recovery means,
When the local station is in the “one-way” mode, only the failure information detected by the local station and the switching request given by the local station are used for the switch means with the pair of working signal lines and the pair of standby systems. While switching the signal line, when the own station is in the “bidirectional” mode, it synchronizes with the other station and switches between the pair of active signal lines and the pair of standby signal lines. And a switch control means . The code content requesting the transition to the “one-way” mode and the code content requesting the transition to the “bidirectional” mode are associated one by one with the unique bit pattern represented by 6 to 8 bits of the APS byte. The communication apparatus according to claim 1, wherein the communication apparatus is provided. When your station is initially in “Bidirectional” mode and the other station is in “One way” mode, keep your station in “Bidirectional” mode and switch to “Bidirectional” mode. APS byte processing means at the time of both-station mode mismatch at the time of initial operation for processing to transmit a transmission frame having a code content requesting to the other station,
At the time of initial operation, when the two-station mode does not match, when a transmission frame having a code content indicating a “bidirectional” mode is sent from the other station to the transmission frame transmitted by the APS byte processing means, the APS byte processing Switching completion notification means for outputting a switching completion notification indicating that automatic mode switching has been completed between both stations to the means
The communication apparatus according to claim 1, further comprising: The communication apparatus according to claim 1, further comprising a table that defines processing operations of the APS byte of the local station and the other station. A pair of working signal lines connecting between the first station and the second station arranged opposite to each other;
A pair of standby signal lines connecting between the first station and the second station;
First station switch means for switching the pair of active signal lines and the pair of standby signal lines on the first station side;
Second station switch means for switching on the second station side between the pair of working signal lines and the pair of standby signal lines;
An APS (Automatic Protection Switching) byte arranged in an SOH (Section OverHead) in a transmission frame arranged in the first station and transmitted through the working signal line from the second station is inputted. In addition to performing processing based on this, the APS byte configured with a code indicating a “bidirectional” mode that simultaneously switches the bidirectional of the signal line when a failure occurs is initially transmitted to the second station. 1 station side APS byte processing means;
The APS byte in the SOH in the transmission frame arranged in the second station and transmitted through the working signal line from the first station is input and processing based on this is performed. A second station-side APS byte processing means for processing to initially transmit an APS byte configured with a code indicating a mode of ”to the first station;
A first station-side APS byte processing fault detecting means arranged in the first station for detecting a fault of the first station-side APS byte processing means;
A second station-side APS byte processing fault detecting means arranged in the second station for detecting a fault of the second station-side APS byte processing means;
When the first station side is in the “bidirectional” mode when the first station side APS byte processing failure detection means detects a failure, the first station side is in the “bidirectional” mode. First station side failure station transition request means for transmitting a transmission frame to the second station with the code content for requesting transition to the “one-way” mode in the APS byte. When,
When the second station side is in the “bidirectional” mode when the second station side APS byte processing failure detection means detects a failure, the second station side is in “bidirectional” mode. Second station side partner station transition request means for transmitting a transmission frame to the first station with a code content for requesting transition to the "one-way" mode. When,
When the APS byte is placed in the first station and the APS byte is sent from the second station to the code content requesting the transition to the “one-way” mode, the first station is set to the “one-way” Change to APS byte when receiving a first station-side transition request for transmitting a transmission frame to the second station by incorporating an APS byte with code content indicating that the own station is in the “one-way” mode. Means,
When the APS byte is placed in the second station, and the APS byte is sent from the first station to the code content requesting the transition to the “one-way” mode, the second station is set to the “one-way” Change to the mode and change the APS byte at the time of receiving the second station-side transition request for transmitting the transmission frame to the first station by incorporating the APS byte of the code content indicating that the own station is in the “one-way” mode Means,
When the first station side APS byte processing failure detection means is no longer detecting a failure, the first station side is changed from the “unidirectional” mode to the “bidirectional” mode. And APS byte changing means at the time of restoration of the first station that incorporates an APS byte having a code content indicating that the APS byte is in the “bidirectional” mode and transmits a transmission frame to the second station;
When the second station side APS byte processing failure detection means is no longer detecting a failure, the second station side is changed from the “unidirectional” mode to the “bidirectional” mode. And a second station restoration APS byte changing means for incorporating a APS byte having a code content indicating that the APS byte is in a “bidirectional” mode and transmitting a transmission frame to the first station;
Code content that is placed in the first station and indicates that it is in the “one-way” mode from the second station after being changed to the “bidirectional” mode by the APS byte changing means when the first station is restored When the transmission frame incorporating the APS byte of the first station side is transmitted, the transmission content is transmitted to the second station with the code content requesting the transition to the “bidirectional” mode. Transition request means;
Code content that is placed in the second station and indicates that it is in the “one-way” mode from the first station after being changed to the “bidirectional” mode by the APS byte changing means when the second station is restored When the transmission frame incorporating the APS byte of the second station side is transmitted, the transmission side frame is transmitted to the first station with the code content requesting the transition to the “bidirectional” mode. Transition request means;
A transmission frame having a code content which is arranged in the first station and requests the transition to the “bidirectional” mode is transmitted from the second station by the partner station transition requesting means at the time of the second station side failure recovery. A first station-side bidirectional mode recovery means for changing the first station to a “bidirectional” mode,
A transmission frame having a code content that is arranged in the second station and that requests a transition to the “bidirectional” mode is transmitted from the first station by the counterpart station transition requesting means at the time of the first station side failure recovery. Second station side bidirectional mode recovery means for changing the second station to the “bidirectional” mode when
When it is arranged in the first station and the own station is in the “one-way” mode, only the failure information detected by the own station and the switching request given by the own station are used for the first station switch means. While switching between the pair of working system signal lines and the pair of standby system signal lines, when the own station is in the “bidirectional” mode, it synchronizes with the second station and attempts to synchronize with the pair of working signal lines. First station switch control means for executing switching between a system signal line and a pair of standby system signal lines;
When it is arranged in the second station and the own station is in the “one-way” mode, only the fault information detected by the own station and the switching request given by the own station are used for the second station switch means. While switching between the pair of working system signal lines and the pair of standby system signal lines, when the local station is in the “bidirectional” mode, the pair of working system lines is synchronized with the first station. Second station switch control means for executing switching between a system signal line and a pair of standby signal lines
A line protection control system comprising: The code content requesting the transition to the “one-way” mode and the code content requesting the transition to the “bidirectional” mode are associated one by one with the unique bit pattern represented by 6 to 8 bits of the APS byte. 6. The line protection control system according to claim 5, wherein the line protection control system is provided. When the first station is placed in the first station and the first station is initially in the “bidirectional” mode and the second station is in the “one-way” mode, the first station is in the “bidirectional” mode. The first station side initial operation is performed so that the transmission frame having the code content for requesting the transition to the “bidirectional” mode is transmitted to the second station. Byte processing means;
Placed in the second station, when the second station is initially in a “bidirectional” mode and the first station is in a “unidirectional” mode, The second station side initial operation for processing to transmit to the first station a transmission frame having a code content for requesting the transition to the “bidirectional” mode. Byte processing means;
At the time of the first station side initial operation, when the two-station mode does not match, a transmission frame having a code content indicating a “bidirectional” mode is sent from the second station to the transmission frame transmitted by the APS byte processing means. A first station side switching completion notification means for outputting a switching completion notification indicating that automatic mode switching between the two stations is completed to the APS byte processing means;
At the time of the second station side initial operation, when the two stations do not match, a transmission frame having a code content indicating a “bidirectional” mode has been sent from the first station to the transmission frame transmitted by the APS byte processing means. Second station side switching completion notification means for outputting a switching completion notification indicating that automatic mode switching between the two stations has been completed to the APS byte processing means
The line protection control system according to claim 5, further comprising: Inputs APS (Automatic Protection Switching) bytes placed in SOH (Section OverHead) in a transmission frame transmitted from the other station placed opposite to the own station on the working signal line, and performs processing based on this. APS byte processing means for performing processing so as to initially transmit an APS byte composed of a code indicating a “bidirectional” mode for simultaneously switching bidirectional signal lines when a failure occurs to the other station An APS byte processing fault detection step for detecting a fault;
When a fault is detected in the APS byte processing means in the APS byte processing fault detection step and the own station is in the “bidirectional” mode, the station that detects the fault switches only the receiving side. A change to the one-way mode, and a request for transition to a partner station in the event of a failure to transmit a transmission frame to the other station with the code content requesting the APS byte to change to the one-way mode;
When the APS byte having the code content requesting the transition to the “one-way” mode is sent from the other station, the own station is changed to the “one-way” mode and the own station is changed to the “one-way” mode. A transition request receiving APS byte changing step of transmitting a transmission frame to the other station by incorporating an APS byte having a code content indicating that the mode is
When no fault is detected in the APS byte processing means in the APS byte processing fault detection step, the own station is changed from the “one-way” mode to the “bi-directional” mode, and the APS byte is changed to “bi-directional”. ”APS byte changing step at the time of recovery from the own station, which incorporates an APS byte having a code content indicating the mode of“
After changing to the “bidirectional” mode by the APS byte changing step at the time of restoration of the local station, a transmission frame incorporating an APS byte having a code content indicating that it is in the “one-way” mode is sent from the other station. When the failure recovery partner station transition request step to transmit the transmission frame to the other station in the code content to request the transition to the "bidirectional" mode,
When a transmission frame having a code content requesting transition to the “bidirectional” mode is sent from the other station by the partner station transition request step at the time of failure recovery, both of the own stations are changed to the “bidirectional” mode. Recovery mode recovery step,
When the local station is in the “one-way” mode, a pair of current connections between the local station and the other station with respect to a predetermined switch means only by the failure information detected by the local station and the switching request given by the local station While switching between the system signal line and the pair of standby system signal lines is performed, when the local station is in the “bidirectional” mode, synchronization with the other stations is performed to establish a pair with the pair of the working system signal lines. Switch control step for switching the standby system signal line
A line protection control method comprising: The code content requesting the transition to the “one-way” mode and the code content requesting the transition to the “bidirectional” mode are associated one by one with the unique bit pattern represented by 6 to 8 bits of the APS byte. The line protection control method according to claim 8, wherein the line protection control method is provided. When your station is initially in “Bidirectional” mode and the other station is in “One way” mode, keep your station in “Bidirectional” mode and switch to “Bidirectional” mode. APS byte processing step at the time of both-station mode mismatch at the time of initial operation for processing to transmit a transmission frame having a code content requesting to the other station;
When a transmission frame having a code content indicating a “bidirectional” mode is sent from the other station to the transmission frame transmitted in the APS byte processing step when the two-station mode does not match during the initial operation, the APS byte processing Switching completion notification step for outputting a switching completion notification indicating that automatic mode switching between both stations has been completed to the means
The line protection control method according to claim 8, further comprising:

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