JPS5957544A - Loopback control system - Google Patents

Abstract

PURPOSE:To form the loopback in a short time at the generation of a failure, by providing some discriminating functions to each node. CONSTITUTION:An input signal of the systems 0 and 1 is received at a receiving section RV of a control circuit CT in each node and the input signal is checked at a level regenerating circuit LV and a clock synchronism circuit CLS. As a result, a loopback control circuit LBC determines a failure state of the pre-stage and command information of the loopback based on the input from the LV and the CSL of the systems 0 and 1 and feeds an output to a transmission switching circuit TLC and a failure information systhesizing circuit EDC. The TLC executes arithmetic logically the input signal from the systems 0,1 and the signal of the loopback to form a prescribed loopback. Further, when a failure detecting signal of the system 0 or 1 is produced to the output of the LBC, it is informed to the next stage with the EDC. Thus, the period from the generation of failure to the formation of loopback is shortened extremely.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a loop bank control system that allows a loop bank to be formed in a short time when a failure occurs in a duplex transmission line.

(2) Prior art and problems As shown in Fig. 1, the loop bank control method uses duplex transmission lines TLI and TL2 that connect multiple nodes NDI, ND2, . . . and includes an integrated monitoring device SV. It is based on orbiting in the opposite direction. When the transmission lines are correct, for example, one of them, TI, 1, is used as the active "0" system, and the other, TI, 2, is used as the backup "1" system. Transmission line TL
When a failure occurs somewhere in only I, the monitoring device SV detects it and immediately switches to using the backup transmission path TL2, so there is no problem in communication between the nodes. However, if a fault occurs in two threads at the same time, such as when transmission lines TLI, TI, and 2 are disconnected, both the active and backup transmission lines become disconnected. When the monitoring device SV detects this, it connects the input and output sides of each transmission line at the nodes on both sides of the disconnection point. Therefore, it is sufficient to provide a connection path, keep a switch therein open, and close it by the output of the control device that has deciphered the command from the monitoring device. A transmission path configuration using transmission paths in both directions in this manner is called a loopback. When a failure occurs in the transmission path, the monitoring device SV can tell that the failure has occurred because the clock is disrupted or the received frame is out of order, but it immediately determines the long-distance location of the occurrence between which nodes. It is not possible. Therefore, when a failure occurs, communication is interrupted and checks are sequentially performed starting from the node NDI closest to the monitoring device SV. That is, node N
If only DI is loop-banked and an abnormal (monitoring device/\ signal is returned, it is known that there is no abnormality from the monitoring device SV to node NDI, so the loop-bank connection of node NDI is released.Next, to node ND2 Similarly, connect the loop bank to the monitoring device SV if the signal is abnormal (
Check to see if it comes back. Do this one after the other and don't go back (
It is tentatively determined that the failure occurs between the failed node and the previous node. Next, a similar check is performed on nodes in the opposite direction from the monitoring device SV to find out where the failure has occurred. As before, when the fault location is confirmed, loopback connections are made to the nodes on both sides of the fault location (
Communication will be resumed. This method requires complicated operations as the number of nodes increases, and at the same time leads to long-term communication interruptions.

(3) Object of the Invention An object of the present invention is to improve the above-mentioned drawbacks and to provide a loop bank control method that can form a loop bank in a short time when a fault occurs in a duplex transmission line.

(4) Structure of the Invention The structure of [Unexploded item] for achieving the above-mentioned object is constructed by connecting a plurality of nodes to each other with duplex transmission lines circulating in opposite directions, and each node is connected to one side of the transmission line. Each node is equipped with a connection path that returns the received signal from one transmission path to the other transmission path at a predetermined time, and a control circuit that controls opening and closing of the connection path. comprising means for detecting a signal interruption and means for notifying an adjacent node of the detected signal interruption state, and a condition between the output of the means for detecting the signal interruption and a signal interruption notification signal from the adjacent node is satisfied. when the control circuit closes the connection path.

(5) Embodiment of the Invention FIG. 2 is a system configuration diagram according to the present invention, and details of the control circuit OT at each node are shown in FIG. 3 and subsequent figures. In Figure 2, compared to Figure 1, the integrated monitoring device SV
is not included in the transmission path, but the SV function is included in the control circuit GT (shown in FIG. 3) at each node.

Therefore, as shown in FIG.
St, failure notification synthesis circuit EDC1 transmission line switching circuit TLC
, a transmitter Dv, a loop bank control circuit LBO1, etc., and components such as level detection from each input terminal to the output terminal of the D system and 1 system exist in parallel in opposite directions, and a loopback control circuit is provided. Control is given to the components in each direction. That is, the input signals of each group are received by the receiving section RV and processed by each circuit for the level reproduction circuit Lv and clock synchronization circuit CLS. As a result, the loop bank control circuit LB
As G, a signal disconnection is detected by a circuit as shown in the example of FIG. FIG. 6 shows an embodiment, in which the transmission line switching circuit determines the failure status of the previous stage and the instruction information of the loop bank based on the input from the level regeneration circuit LV of the 0 system and 1 system and the clock synchronization circuit C8L. TLC1 fault notification synthesis circuit EDC
This is what is output to. For example, in each signal level clock, there may be a level error in which the input signal level falls below the threshold level, or the average input signal level falls below the threshold level for a certain period of time, or a clock error such as clock loss of synchronization or switching interruption. When a logical operation is performed on the signal that detected this and the same type of signal from another system, the output terminals of the 0 system fault and 1 system fault become “H”.
” indicates that the signal is disconnected from the previous similar node. Roof” Hack LB-0, Loop Back LB
If the -1 terminal becomes "H", this means that there is a transmission line failure from the previous node of the same system, and the transmission line from the previous node of the other system is normal, but it indicates that a failure has occurred before that. It shows. Therefore, when the relevant node detects "H" in LB-0, it loops from system ○ to system 1, LB-I K
When "H" is detected, it is determined that loopback from the 1st system to the D system is required. When switching the transmission path by generating this loop bank request signal, the third
The transmission line switching circuit TLC shown in the figure is used. An example of the circuit is shown in Figure 4, where the input information from the 0 system and 1 system is set to 0.
System transmission path, switching part that determines the direction of the loop-excluded bank sent to the 1st system transmission path (0 → 1 system, 1 → 0 system), and system switching and output when input information is taken into the data processing unit in the node. It includes circuits for system switching, etc. The condition for switching the transmission path and executing a so-called loopback is one of the following two conditions.

■ When one system's transmission line is disconnected (level and clock errors occur at the same time), and a transmission line disconnection is notified at another point on the other system.■ When the output transmission line from the own node is disconnected. When a disconnection is notified from an adjacent node and a transmission line disconnection at another point in another system is notified, the transmission line switching circuit TLC transfers input signals from each prefecture and loop banks LB-0 and LB-1. A loop bank is formed at a predetermined time by performing logical operations on the signals. Also, when a 0-system or 1-system fault detection signal appears at the output of the loop bank control circuit LBG, the fault notification synthesis circuit EDG
Notify the next stage. In this example, the simplest fault notification is used, a series of "1" is used to notify the next node of a transmission path failure from the previous node, and a series of "1" is used to notify the previous node of a transmission path failure from the previous node. It is a series of ball011. As a result, each node can detect transmission path failures before the previous node and transmission path failures from its own node by detecting only clock errors and the simultaneous occurrence of clock level errors without a special receiving circuit.

Note that even if there is no communication between nodes on the transmission path, “0” continues and “1” continues.
``It is assumed that a specific focus pattern other than the quick connection is always transmitted during normal operation.The specific circuit for detecting a transmission path failure is as described above (see FIG. 6).

Figure 7 shows node N with the same configuration as Figure 2.
This is a diagram explaining the loop bank when a failure occurs in both systems between D-B and ND-0. FIG. 7A shows the block configuration 1 showing the connection after the loop bank, and FIG. FIG. 7 is a diagram illustrating control conditions and states for FIG. 7; In the figure,
Corresponding to each node (ND-A″-ND-D), the flow of failure notification information when a failure occurs, the flow of failure notification information between nodes, and the control of loop bank formation as a transmission path operation are shown, and after the loopback The failure detection situation is shown in the lower part.In failure detection, node B corresponds to FIG. 7A.

This shows a case where a failure occurs in both systems (O system, 1 system) between 0 and 0 (in the case of a failure in one system, it is sufficient to simply switch between the active and backup systems, so this is not directly related to the present invention). (omitted). In the fault detection section of Figure 7B, "DT" indicates that a level and clock error was detected in each prefecture of the 0 system and 1 system for the node, and the arrow in the fault notification section indicates that It is shown that the fault is notified in that direction by the fault notification synthesis circuit in Fig. 5.The loop bank control circuit of each node determines the operation shown in the section of transmission line operation in Fig. 7B. By operating the transmission line switching circuit, in FIG. 7A, a loop bank is formed at nodes ND-B and ND-C according to the above condition゜Figure 8 shows an example where a failure occurs at different locations between nodes in each prefecture. Figure 8 A shows node ND-B in the 0 system.
, between ND-0 and ND-B in i system.

This shows that due to a failure between ND-A, a loop bank was formed between ND-A and ND-0 according to the above-mentioned condition (2). FIG. 8B is an operation table of FIG. 8A. ND in the diagram
-B is notified by both ND-A and ND-C that the transmission path from its own node is faulty, but the above
Loop banking is not performed because both of the following are not true.

Figure 9 shows the connection between nodes ND-A and ND-8 in the 0 system.
This is an example of a failure occurring between nodes ND-G and ND-B in the system. In this case, ND-A changes from ND-8 to HD-
C is notified by ND-8 that the transmission path from its own node is faulty, and a loop bank is formed between nodes ND-A and ND-0 according to the above-mentioned condition (2). FIG. 9B shows the operation table of FIG. 9A.

(6) Effects of the Invention In this way, according to the present invention, by providing each node with some judgment function, when a failure is detected, it is judged whether or not to form a loopback, and when necessary, Immediately form a loop bank. Therefore, the period from the occurrence of a failure to the formation of a loop bank is extremely short, making it suitable for effective processing of information. Also, the control circuit and fault notification/communication circuit required for this can be simple as shown in the example.

[Brief explanation of the drawing]

Fig. 1 is a system configuration diagram explaining the conventional loop check method, Fig. 2 is a system configuration diagram of the present invention, and Fig. 6
The figure shows the configuration of the control circuit in the node of FIG. 2 as a specific embodiment of the present invention, and FIGS.
The circuit configuration examples in the figure, FIGS. 7, 8, and 9, show diagrams of the loop circuits formed when a failure occurs between nodes and their respective operations. NDI, ND2..., ND-A, ND-B
, ND-C, ND-D... node, TLI,
TL2, 0 system, 1 system...Transmission line, CT...control circuit, I, V...-level regeneration circuit, CLS-.... Clock synchronization circuit, LBC...Lubno (Tsuku1tt)
lJ control circuit, TLC...transmission line switching circuit, EDO...
・Disability JM circuit patent applicant Fujitsu Ltd. Agent Patent attorney Eisuke Suzuki ND2 Figure 1 ND-D Figure 2 Red Chikkine Ichimasaichi: (Method) (1982)
December 1g, Mr. Kazuto Wakasugi, Commissioner of the Japan Patent Office ■, Minor case indication 1982 4 + Application No. 150481 2, Name of the invention Loop hack control method 3, Relationship with the case to be amended Patent applicant address Kanagawa prefecture Former 5th address, Kamioda, Nakahara-ku, Yozaki-shi Name (522) Representative of Fujitsu Co., Ltd., former Takuma Yamamoto 4, Agent address: 2-13-35 Yoyogi, Shibuya-ku, Tokyo, Date of amendment order: November 1980 June 30th, 6, 2016, details subject to amendment, column 7 for brief explanation of reproduced drawings, content of amendment as shown in the attached ■) page 12, line 12 ray of the specification. Ichimasa '?!f' (self-motivated) 12 Mt in 1980 (11 per day, Kazuo Wakasugi, 1st official, 1988 patent Application No. 150481 2, Name of the invention Loop eight control method 3, Relationship with the amendment 1 case Patent applicant address 1015 Kamiodanaka, Nakahara-ku, Yozaki City, Kanagawa Prefecture Name (522) Fujitsu Co., Ltd. Representative Yama
Hon Fuki Makoto 4, agent address: 6th floor, 3rd floor of Hirota Pill, 2-13-3 Yoyogi, Shibuya-ku, Tokyo, subject of amendment Akira? ■Detailed explanation of the invention column 7 in Book 1, content of amendments As per attached sheet (1) "Operation table" in the first and second lines of page 11 of the specification is changed to "
"Diagram explaining control conditions and states". (2) ``Operation table'' on page 13, line 13 of the specification.
FIG. 1 is a diagram illustrating control conditions. ” he corrected.

Claims (1)

[Claims] A duplex transmission line that circulates in opposite directions is constructed by connecting a plurality of nodes to each other, and each node connects the received signal from one transmission line back to the other transmission line at a predetermined time. In addition to being equipped with a control circuit for controlling the opening and closing of the transmission line, each node is also equipped with means for detecting a signal disconnection on the normally used transmission line, and means for notifying adjacent nodes of the detected signal disconnection state. and a loopback control system characterized in that when a condition between the output of the means for detecting the signal disconnection and a signal disconnection notification signal from an adjacent node is established, the control circuit is controlled to close the connection path.