JP2002374229A - Changeover control device and method for duplicate transmission line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission line changeover device and method that can change over a signal processing section and a changeover control section at the same time, and surely matched with inter-station changeover information items to be sent to an opposite station device, so as to correctly change over transmission lines. SOLUTION: The transmission line changeover device is provided with a line interface means 10, respectively provided to a 0-system transmission line and a 1-system transmission line, each comprising a signal processing means 13 that extracts a received signal from the transmission line and generates a fault event; a fault supervisory means 12 that supervises a device fault in the 0-system and the 1-system, a changeover control means 11 that discriminates the changeover of the transmission lines and outputs inter-station switching information to an opposite device and a signal denoting an active/standby transmission line; and a transmission information selection means 14 that selects either of the inter-station switching information items outputted from changeover means of the own system and the other system, and with a confounding means 24 that selects either of the signals received by 0-system and 1-system line interface means, on the basis of the signals denoting the active system and the standby system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system switching device for a duplex transmission line composed of a system 0 transmission line and a system 1 transmission line, and more particularly to system switching of a duplex transmission line employing an APS (Automatic Protection Switch) switching system. It is related to equipment and system switching method.

[0002]

2. Description of the Related Art In a device for accommodating a transmission line duplexed between two terminal stations, an I-mode is used as a switching system for the duplex transmission line.
An APS switching method defined in the TU-T recommendation is known. The APS switching method is based on STM (Synchronous Trans
fer Mode) By exchanging inter-station switching information such as a switching request with the remote device using K1 and K2 bytes in the SOH (Section Over Head) of the frame, when a failure in the transmission path etc. This is a transmission line switching method for switching the transmission line and the line interface unit without intervention of the transmission line. In the APS switching method, it is also possible to fix the operation system of the transmission line by command switching according to an instruction from a higher-level device or by stopping the system switching function. As a conventional device, a transmission line switching device described in Japanese Patent Application Laid-Open No. 10-243055 is known. FIG. 3 shows the configuration of a conventional apparatus. In the conventional transmission line switching device, a signal processing unit 13 that performs signal processing of a transmission / reception signal on a transmission line, a failure detection unit 17 that outputs event information according to a failure of the transmission line, and a system from the event information or the game device. An information collection unit that updates internal state information indicating a processing state of communication processing with the game device based on the switching signal; and a system switching signal to the game device based on the internal state information from the information collection unit and an internal device. A line interface unit 10 composed of a switching control unit 11 that outputs a switching signal to a confounding unit is provided for each of the duplicated transmission lines, and a signal processing unit of any system receives the signal based on the switching signal. A confounding section 24 for selectively outputting a signal is provided.

[0003] The information collecting unit 11-0 communicates with the information collecting unit 11-1 of the other system so that the internal state information possessed by the information collecting unit is always the same in both systems, that is, synchronized. Thus, the system switching signal output from the line interface unit to the opposite device has the same contents in both systems.

[0004]

In the conventional transmission line switching device described above, the signals input from both transmission lines are out of phase, so that the internal state information of both systems is reliably synchronized. Therefore, it is necessary to obtain a signal for synchronization from an external device, and when an error occurs in the synchronization signal or in a device in which a signal to be synchronized cannot be obtained from the external device, the operation system and the standby system need to be obtained. There is a possibility that inter-station switching information to be transmitted to the opposite device in the line interface unit may not match.

[0005] Further, since the signal processing unit and the switching control unit are constituted by one line interface board, that is, handled as one maintenance unit, the signal processing unit or the switching control unit corresponding to the active transmission line is used. If a failure occurs in any of them, the signal processing unit and the switching control unit are switched at the same time. For example, if an abnormal system switching signal is sent to the remote device due to a failure of the switching control unit in one of the line interface units, incorrect switching occurs because the switching procedure with the remote device is not performed correctly. Alternatively, the line interface unit on which the switching control unit that has failed due to the inability to perform system switching may become the active system.

The present invention solves the above-mentioned problems in the prior art, and a first object of the present invention is to provide an information processing system that can correctly store information even if the internal state information held by the line interfaces of both systems is not completely synchronized. It is an object of the present invention to provide a transmission line switching device and a transmission line switching method capable of switching transmission lines.

Another object of the present invention is to transmit correct inter-station switching information to a remote control unit even when a switching control unit of a single-system line interface unit fails, and to ensure that a line interface unit free from failure operates. It is an object of the present invention to provide a transmission line switching device and a transmission line switching method which are systems.

[0008]

According to the present invention, an object of the present invention is to provide a switching control apparatus for a duplex transmission line composed of a system 0 transmission line and a system 1 transmission line, which extracts a received signal from the transmission line and detects a failure event. Signal processing means for generating and processing an output signal to a transmission path; failure monitoring means for monitoring system 0 and system 1 device failures; inter-station switching information and transmission path failure received by the signal processing means The transmission line switching is determined based on the event and the switching information obtained by collecting the device failure event obtained from the failure monitoring means, and the signal indicating the inter-station switching information to the opposite device and the operation / spare of the corresponding transmission line. And a transmission interface selecting means for selecting any one of the inter-station switching information output from the switching control means of the 0 system and the switching information of the 1 system. Road and 1 The 0-system line interface unit receives from the signal indicating the operation / standby output from each of the line interface unit corresponding to the 0-system transmission line and the line interface unit corresponding to the 1-system transmission line, provided in each of the transmission lines. This is achieved by providing a confounding means for selecting any one of the received signal and the signal received by the primary system line interface means.

[0009] The object of the present invention is that the transmission information selecting means comprises:
The comparison means for comparing the inter-station switching information output from the switching control means of the system 0 and the switching means of the system 1 is output from the switching control means of the own system if the comparison results in the comparison means match. Transmission information selecting means for selecting the inter-station switching information output from the active switching control means by referring to the signal indicating the operation / spare of the transmission path.

Further, the object of the present invention is to, when a failure occurs in the switching control means, select the inter-station switching information output from the switching control means of the system in which the failure has not occurred in the transmission information selecting means, and This is achieved by outputting information indicating the operation / standby of the corresponding transmission line, which is output to the device and output from the switching control means in which the failure has occurred, as a standby.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a switching control apparatus and a switching control method for a redundant transmission line according to the present invention.

FIG. 1 is a block diagram of a switching control device for a duplex transmission line composed of a system 0 transmission line and a system 1 transmission line according to an embodiment of the present invention. Line interface units 10-0, 1
Reference numerals 0-1 denote devices to be duplicated. The switching control units 11-0 and 11-1 and the failure monitoring units 12-0 and 12-
1, signal processing units 13-0 and 13-1, transmission information selection unit 1
4-0, 14-1, inter-system interface unit 21-0, 2
1-1, and exchanges information between systems via an intersystem signal line 22. Note that the subscripts -0 and -1 shown in the reference numerals are 2
This indicates that the multiplexed devices are of the system 0 side and the system 1 side. Intersystem interface units 21-0 and 21-1
Is the system interface information including the transmission K byte 34, the reception K byte, the transmission line failure event 31, the own system failure information 44, the other system failure information 45, and the mounting information 46 shown in FIG. To send and receive. Here, K bytes are inter-station switching information. The own system fault information 44 includes device fault information of the line interface unit 10 and fault information of the switching control unit.

The switching control unit 11-0 is provided with a fault monitoring unit 12-0.
, The received K byte extracted by the signal processing unit 13-0 and the transmission line failure event 31-0,
And other system information 32 from the intersystem interface unit 21-0
With −0 as an input, the selection system of the line interface and the transmission K byte are determined, and the switching signal 33-0 is transmitted to the interlacing unit 24 of the SW unit 23 at the subsequent stage. The transmission K byte 34-0 determined by the switching control unit 11-0 is input to the transmission information selection unit 14-0, and at the same time, the inter-system interface units 21-0, 21
-1 to the transmission information selection unit 14-1 of the other system. Similarly, the switching control unit 11-1 also stores the failure information 35-1 and
Receive K byte 31-1, intersystem interface unit 21-1
, The switching signal 33-1 is output to the interlacing unit 24 of the SW unit 23, and the transmission K
Byte 34-1 is stored in transmission information selection units 14-0 and 14 of both systems.
-1.

FIG. 2 shows an embodiment of the transmission selecting section. The transmission information selection unit 14-0 includes transmission K bytes 34-0 of both systems,
After inputting the signal 34-1 and passing through the comparator 15, the transmission K bytes selected by the transmission selector 20 controlled by the selector control unit 16 are output to the signal processing unit 12. The transmission K bytes input to the signal processing unit 12 are inserted into the overhead of the main signal 30 to perform switching with the remote device.

The comparator 15-0 of the transmission information selector 14-0
Indicates whether the comparison operation is performed / not performed in the failure information of the failure monitoring unit 12-0, and if the result of comparing the transmission K byte 34-0 of the system 0 with the transmission K byte 34-1 of the system 1 is identical. , The selector operation permission signal 25-0 to the selector control unit 1.
Notify 6-0. The selector control unit 16-0 includes the comparator 1
In synchronization with the selector operation permission signal 25-0 from 5-0, the selection system determined by the switching control unit 11-0 is set as the selector selection system. Since the transmission information selection unit 14-1 of the first system performs the same processing as the transmission information selection unit 14-0 of the zero system, the transmission K bytes of the selected system are always transmitted in a state where they match in the 0/1 system. You. Even if the internal state information held by the line interfaces of both systems is not completely synchronized by the above operation, the transmission K bytes output by the line interfaces of both systems can be matched. At this time, even if the internal state information is temporarily different, the transmission K bytes of both systems match because the selector selection system is not changed.

FIG. 5 shows a connection state between the own station apparatus and the opposite apparatus. The own station apparatus 50 according to the present invention comprises line interfaces 10-0 and 10-1 of the 0 system and 1 system, and 0 system and 1 system, respectively. The inter-system signal line 22 for connecting the line interface of each system, and the game apparatus 51 is composed of the line interfaces 52-0 and 52-1 of the system 0 and the system 1, respectively. Line interfaces of the system 0 and the system 1 of the device 51 are connected by lines 53-0 and 53-1 transmitted from the own station device 50 to the opposite device 51,
A line 54-transmitted from the opposite device 51 to the own device 50
0, 54-1.

Next, the notification operation of fault information when a fault occurs according to the present embodiment will be described with reference to the sequence diagram of FIG. In the operation state shown in FIG. 5, when the system 0 line is operating in the selected system state, when a failure occurs in the system 0 line 54-0 transmitted from the remote control device 51 to the own station device 50, the system 0 K at the line interface 10-0 of
A line failure is detected by a byte (60), and a notification of the line failure is sent to the 0-system switching control unit 11-0 (61). At the same time, it also notifies the 0-system inter-system interface 21-0 (62) and transfers the information to the 1-system inter-system interface 21-1 (63), and sends the information to the 1-system switching control unit 11-1. Also notifies a line failure (64). By doing so, information can be transmitted / received using the interface connecting the systems, so that each switching control unit that operates independently of each system can be notified of the occurrence of the same failure. At this time, the fault occurrence information does not need to be notified to the switching control units of both systems at the same time, but may be notified asynchronously.

Next, the switching operation at the time of occurrence of a fault according to the present embodiment will be described. In the operation state shown in FIG. 5, when the 0-system line operates in a selected
When a failure occurs in the system 0 line 53-0 transmitted from 0 to the game apparatus 51, the game apparatus 51 that has detected the line failure of the system 0 line 53-0 transmits a K byte indicating a request to switch to the system 1 Is transmitted to the 0-system line 54-0 and the 1-system line 54-1. The K bytes indicating the transmitted switching request are extracted by the signal processing units 13-0 and 13-1, and the switching control unit 11-
0, 11-1 is notified of a request to switch the game device. The switching control units 11-0 and 11-1 that have received the notification operate independently according to the flowchart of FIG. First, reference is made to the fault status of the transmission line fault and the device fault (70), and to the received K bytes (71).
The system switching in the S system is determined (72). Since the switching of the device occurs due to the determination of the system switching (73), the switching signal 3
3-0, 33-1 is sent to the confounding part (74). At this time, the system switching state transits to the 1-system selection state.
The system switching control unit 11-0 sends a signal to be a standby system,
The switching control unit 11-1 of the first system sends a signal to be the active system. After that, K bytes indicating the switching response are transmitted (7
5), setting of the transmission selectors 20-0 and 20-1 is performed (76).

The setting of the transmission selectors 20-0 and 20-1 is performed according to the flowchart shown in FIG. The switching control unit 11-1 of the system 1 refers to the failure state of the system 0 (80),
It is determined that no device failure has occurred in the line interface 10-0 of the system (81), and the selected system is the system 1 (other system) (82), and when the comparison of the K byte signal matches (83).
The transmission selector 20-1 is set so that the transmission K bytes of the first system are transmitted (85). 0-system switching control unit 1
1-0 refers to the failure status of the first system (80), determines that no device failure has occurred in the line interface 10-1 of the first system (81), and the selected system is the first system (other system). Yes (8
2) In the case where the comparison of the K-byte signals matches (84), the transmission selector 20-0 is set so that the 1-system transmission K-byte is transmitted (85). By doing so, the switching control unit that operates independently for each system can transmit the same transmission K byte to both devices even if the input information shifts due to a delay difference in information exchanged between the systems.

When the switching control unit 11-0 of the 0 system has failed, the switching control failure monitoring unit 19-0 detects the failure state, and through the inter-system interface unit 21, the failure monitoring unit 12-1 of the 1 system. To the switching control unit 12-0.
The switching control unit 11-1 of the first system refers to the failure state of the failure monitoring unit (80), and determines that the other switching control unit is in the failure state (8).
7), the comparison operation of the comparator is set as not performed (88).
The switching control unit 11-1 sets the selection system of the transmission selector to its own side (89). On the other hand, the switching control fault monitoring unit 19-0
Sends a forced selection signal to the selector control unit 16-0, and the selector control unit 16-0 forcibly selects the selector on the other system side.

According to the above processing, even if the switching control unit of one system line interface unit fails, the switching of the line interface unit is performed using the switching control function of the other system switching control unit. Process that allows the selector of the switch control unit to be directed to the system of the switching control unit in which no failure has occurred, so that the correct transmission K byte is sent to the opposite device, and the line interface unit without failure can be reliably used as the active system. It becomes possible.

[0022]

As described above, according to the present invention, even if the internal state information possessed by the line interfaces of both systems is not completely synchronized, the transmission information selection unit causes the same line interface units of both systems to transmit the same information. Since the transmission K bytes are transmitted, the transmission path can be correctly switched between the terminal and the opposite device.

Further, even when the switching control unit of one of the line interface units fails, a correct transmission K byte is transmitted to the remote control unit, and the line interface unit free from the failure reliably becomes the operation system. And a transmission path switching method.

[Brief description of the drawings]

FIG. 1 is a block diagram of a duplex line interface device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of functions of a transmission information selection unit that selects a transmission K byte.

FIG. 3 is a block diagram of a conventional duplex line interface device.

FIG. 4 is an explanatory diagram showing details of transmission / reception signals of an inter-system interface unit.

FIG. 5 is a connection diagram of devices having a redundant transmission line.

FIG. 6 is a sequence diagram of a notification operation when a failure occurs according to an embodiment of the present invention.

FIG. 7 is a flowchart of a system switching operation according to an embodiment of the present invention.

FIG. 8 is a flowchart of a setting operation of a transmission selector in one embodiment of the present invention.

[Explanation of symbols]

10 line interface, 11 switching control unit, 12
Failure monitoring unit, 13: signal processing unit, 14: transmission information selection unit, 21: inter-system interface unit, 22: inter-system signal line,
Reference numeral 23: SW unit, 30: Main signal of transmission line, 31: Received K byte and transmission line failure event, 32: Other system information, 33:
Switching signal, 34 ... K bytes to be transmitted.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuya Shinohara 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Hitachi, Ltd.Communications Division (72) Inventor Keisuke Fukuda 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa (72) Inventor, Yoichi Morimoto, 180 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside Hitachi Telecommunications System Co., Ltd. (72) Takehiko Watanabe 180, Totsuka-cho, Totsuka-ku, Yokohama, Kanagawa, Japan F-term (reference) in Ritsumeikan Communication System Co., Ltd.

Claims (5)

[Claims] 1. A switching control device for switching a redundant transmission line composed of a system 0 transmission line and a system 1 transmission line by exchanging inter-station switching information with a remote device, extracting a received signal from the transmission line and generating a failure event. Signal processing means for generating the signal and processing the output signal to the transmission line, fault monitoring means for monitoring the system failure of the system 0 and system 1, inter-station switching information and transmission line failure received by the signal processing means. The transmission line switching is determined based on the event and the switching information obtained by collecting the device failure event obtained from the failure monitoring means, and the signal indicating the inter-station switching information to the opposite device and the operation / spare of the corresponding transmission line. And a line interface means comprising transmission information selection means for selecting any of the inter-station switching information output from the system 0 switching control means and the system 1 switching control means. transmission In each of the transmission line and the 1-system transmission line,
From the signals indicating the operation / spare output from each of the line interface means corresponding to the system 0 transmission line and the line interface means corresponding to the system 1 transmission line, the signal received by the system 0 line interface means and the system 1 line interface A switching control device for a duplex transmission line, comprising a confounding means for selecting any of the signals received by the means. 2. A comparison unit, wherein the transmission information selection unit compares the inter-station switching information output from the 0-system switching control unit and the 1-system switching control unit, and a comparison result obtained by the comparison unit matches. In this case, there is provided a selector unit for selecting the inter-station switching information output from the active switching control unit by referring to the signal indicating the operation / standby of the transmission line output from the own switching control unit. The switching control device according to claim 1, wherein: 3. A method for switching a redundant transmission line composed of a system 0 transmission line and a system 1 transmission line by exchanging inter-station switching information with a remote device, extracting a received signal from the transmission line and generating a failure event. Signal processing means for generating the signal and processing the output signal to the transmission line, fault monitoring means for monitoring the system failure of the system 0 and system 1, inter-station switching information and transmission line failure received by the signal processing means. The transmission line switching is determined based on the event and the switching information obtained by collecting the device failure event obtained from the failure monitoring means, and the signal indicating the inter-station switching information to the opposite device and the operation / spare of the corresponding transmission line. And a line interface means comprising transmission information selection means for selecting any of the inter-station switching information output from the system 0 switching control means and the system 1 switching control means. Transmission line and 1 system A switching control method for a switching control device, provided on each of the transmission paths, and including a confounding means for selecting any one of a signal received by the 0-system line interface means and a signal received by the 1-system line interface means; The switching information obtained by the failure monitoring means is input to the switching control means of both systems, and based on the switching information input from both systems, the switching control means of the 0 system and the 1 system independently control the transmission line switching. Making a judgment, outputting inter-station switching information to the opposite device to the signal processing means of both systems, and selecting a signal received by the line interface means of the active system by the confounding means. Switching control method. 4. The transmission information selecting means compares the inter-station switching information to the opposite device input from each of the 0 switching control means and the 1 switching control means. Selecting the inter-station switching information output from the switching control means of the interface means and outputting it to the game device,
4. The switching control method according to claim 3, wherein if the compared contents do not match, the inter-station switching information of the system selected before the mismatch is output to the game apparatus. 5. When a failure occurs in the switching control means, the transmission information selection means selects inter-station switching information output from the switching control means of a system in which no failure has occurred, and sends the selected information to the remote device. 4. The switching control method according to claim 3, wherein the information indicating the operation / standby of the corresponding transmission line, which is output from the switching control means in which the failure has occurred, is set as the standby and output.