JPS6119254A - Restoration detecting system of transmission fault in duplicated ring network - Google Patents

Abstract

PURPOSE:To improve the safety of the titled system by confirming the restoration of a fault between adjacent degenerated networks and confirmation of fault restoration of a one system cable so as to control the network accordingly. CONSTITUTION:Transmission stations 21-26 are connected to computers arranged dividedly and various terminal devices 11-16, and the transmission stations 21-26 are connected to duplicated transmission lines 1, 2. Then the transmission stations 21-26 consist each of control sections 31-36, receives 411-416, 412-426 and transmitters 511-516, 521-526. An internal bus 90 is connected to a CPE50 of the control section 24 of the transmission stations 21-26, and a transmission control section 60, a network constitution control section 70 and a supervisory control section 100 are connected to the bus 90. Then the transmission stations 21-26 transited in the form reflecting transmission lines 1, 2 transmit respectively the priority information assigned to the own station and a fault recovery supervisory signal added to set the presence of reception confirmation to the outside of the network. When the reception of the supervisory signal confirms the loop circulation of the priority of the supervisory signal transmitted by itself, the reconstitution control of the network is attained.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a duplex loop transmission system having two sets of transmission lines with different transmission directions, and in particular, this system is capable of disabling multiple degenerate networks due to the occurrence of a transmission failure. The present invention relates to a control method suitable for accurately and promptly recognizing recovery from a disorder and returning to the raw cotton composition when the cotton is differentiated into a raw cotton composition.

[Background of the invention]

The following methods are known as conventional transmission failure recovery detection methods. That is, (1) after transitioning to the degenerate network configuration, this configuration is periodically released and a reconfiguration operation is attempted.

(2) Information is sent to the outside of the network from the transmission path return station, and when the circulation of the information is detected, it is recognized as failure recovery. (%Opened in 1983
(No. 50639) Each of these conventional methods has the following drawbacks.

In method (1) above, transmission is interrupted due to useless attempts to recover from failures. Furthermore, when multiple degenerate networks occur, it is necessary to synchronize recovery attempts between these networks, and if this is not done, there may occur cases where the system cannot return to its original form even though the fault has been recovered.

Furthermore, in the method (2) above, depending on the failure recovery status, there may be a case where the process shifts to a wasteful reconfiguration operation.

This is the case, for example, when a disorder in either the outer or inner system is recovered after differentiation into two degenerate networks.

As described above, when one network is divided into a plurality of degraded networks due to the occurrence of a transmission failure, conventional failure recovery detection methods are insufficient.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a simple method for detecting recovery from a transmission failure that can be recombined or extended in a degenerate network that has a loop-blocking configuration.

[Summary of the invention]

The present invention focuses on the fact that recovery from a failure can be detected if it is confirmed that the information sent from the degenerate network to the outside of the network is received by an adjacent network, or if it is confirmed that the information has gone around the loop. , the information is provided with items for priority and reception confirmation to adjacent networks.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the overall configuration of a ring transmission system to which the present invention is applied. As shown in the figure, computers and various terminals 11 to 16 distributed in factories, pill centers, universities, etc. join one transmission system via transmission stations 21 to 26. Although the number of stations is set to 6, there is no particular limit.In order to improve system availability, the transmission path is usually made redundant with two sets of transmission paths with different transmission directions, and the transmission path 1.2 and the transceivers 411-416, 421- 426,
Consists of 511-516, 521-526. Control unit 31
36 executes transmission control, network configuration control, failure recovery detection, ink-face control with machines, terminals, etc. If there is no fault in the transmission path, transmission is performed using one of the transmission paths (the side indicated by the thick line in the figure). Causes of transmission failure include disconnected lines (including poor connector contact, etc.)
There are various reasons such as short circuit, transmission station power outage, repeater failure, etc., but information reception depends on signal level, band, modulation/demodulation rules, etc.
1. Since various items are checked, the occurrence of a failure is recognized as a valid signal receiving station at the downstream transmission station. Normally, when a failure occurs in the transmission line currently in use, it switches to the other standby side. Furthermore, when a fault occurs across the transmission lines of both systems, a so-called loopback configuration is adopted in which the transmission line is looped back at a transmission station adjacent to the fault so as to disconnect that location from the system.

FIG. 2 shows an example in which such double-system failures occur at multiple locations and multiple independent small loops are formed.

As shown in the figure, in this configuration, transmission with devices outside the own network is not possible, so it is called a degenerate network. Therefore, to further improve system availability, it is necessary to be able to connect degenerate lines immediately after failure recovery.

However, depending on the recovery situation, there may be cases where it is better not to proceed with network reconfiguration. For example, in Figure 2, the fault location a
1 + bI! Even if C2 recovers, the degenerate lines cannot be connected to each other, but when al and a2 recover, transmission stations 21 and 22
, 23.26 can be migrated to one network. From these examples, it can be seen that failure recovery situations in which recombination is possible are as follows.

(1) When both lines between networks are restored.

(2) When all failures are recovered in either system 1 or system 2.

In order to achieve the above items, it is first necessary to send some information from the terminal station of the degenerate network to the outside of the network, and this is hereinafter referred to as a failure recovery monitoring signal. In order to confirm the above (1), the monitoring signal reception status from the partner system is included in the monitoring signal sent from the own network. In addition, to confirm (2) above, it is necessary to transmit the monitoring signal received from the other party's system to the other terminal station via its own network and have it retransmitted, but this will increase the amount of data to be transferred, so this is not recommended. The following measures are required to reduce this.

(a) A unique supervisory signal priority is given to each transmission station and sent at the initial stage.

(b) When receiving a supervisory signal from outside the network that has a higher priority than that transmitted by the local station, subsequent transmissions will be changed to this signal.

It also sends notifications to other ends within the network.

(C) When a command to send a supervisory signal is received from the other end of the network, it compares the priority of the supervisory signal currently being sent by its own station, and changes to this priority only if the command is higher. Sends a monitoring signal.

FIG. 3 shows the format of the monitoring signal sent outside the network. In this example, IEEE p is used as the transmission control procedure within the network.
project adopted the retail token ring system recommended by the 802.5 committee. Since it is better for the supervisory signal to be easily distinguished from the normal frame format, the start delimiter DS is an abort sequence as shown in Figure (a).
and end delimiter DE, followed by 1-bit supervisory signal detection (receipt confirmation) information S.
A format is adopted in which R and priority code information PR of 7 bits or more are given. As is well known, delimiter DS, D
B has a pattern that is uniquely detected at the modulation/demodulation level, and the sign proportionality of the symbol is shown in FIG. Digital information such as supervisory signal detection signal (SR) and priority code PR is differentially Manchester encoded, and there is a signal change at the center of each bit. The distinction between 0'' and '1' is made by the level change from the previous bit, and in this example, the presence of change is assigned to the former bit, and the absence of change is assigned to the latter. On the other hand, J included in the delimiter.

The K bit deviates from this encoding rule; there is no change at the center of the bit, and the distinction between the two is based on the level change from the previous bit.

FIG. 4 shows the hardware configuration of a transmission station according to an embodiment of the present invention. Since all the transmission stations may have the same configuration, the transmission station 24 is shown as an example here. The transmission station has two sets of transmitters 514 and 524 and two sets of receivers 414 and 424 corresponding to the two sets of transmission lines 1.2. The control unit 34 includes transmission multiplexers 41 and 42 that select information to be sent to the line, a reception multiplexer 43 that selects which of the two lines will be used for reception, and a transmission control unit (TC) that executes a transmission control function.
) 60, an assembly control unit (RC) 70 that selects and commands the multiplexer, a supervisory control unit (SC) 100 that monitors failure conditions outside the network when the main station adopts a loopback configuration, and an ink with the connected equipment 14. The system is comprised of an interface m (I N T ) 80 that controls the interface, a central processing unit (CPE) 50 that performs communication management, etc., and an internal bus 90 that connects the above-mentioned units. In addition,
The central processing unit (CI'E) 50 includes a microprocessor, memory, timer controller, and interrupt controller (not shown).

DMAC (Direct-Memory Access
Control 1er) etc. In the transmission multiplexer 41, (a) a supervisory signal output SS from the supervisory control section (SC) Zoo;

0 receiver 414 or 4,24 received data R,
D, (C) Transmission data S from the transmission control unit (TC) 60
Select one from the three D's and send it to the line. When using the transmission path of system 1, the reception multiplexer 43 is RD.
The transmission multiplexer 41 selects the L side, and the C942 selects the B side.
The track maintenance configuration control unit 70 selects each of the following. Similarly, if a 2-system transmission path is used, the reception multiplexer 43
selects the RD Z side, and the transmission multiplexer 41 selects B,
42 selects C, respectively. In addition, the main station connects the 1st transmission line to 2nd line.
When looping back to the system, the reception multiplexer 43 is on the RD l side, the transmission multiplexer 41 is on the A,
42 is commanded by the track maintenance configuration control unit 70 which selects C respectively. Similarly, when looping back the transmission line of system 2 to system 1, the reception multiplexer 43 is connected to the RD x side,
The transmission multiplexer 41 selects C942 and A, respectively. Network configuration control unit 70 that detected the occurrence of a transmission failure in the active system
Then, it is checked whether the local station is adjacent to the fault, and if so, each multiplexer is controlled to adopt a loopback configuration. At the same time, it instructs the supervisory control unit (SC) 100 to start a failure recovery detection operation. The loopback state continues until a response confirming recovery is received.

FIG. 5 shows the hardware configuration of the supervisory control section 100, which is directly related to the present invention, and will be explained in detail below.

When the main station adopts a loopback configuration, the network configuration side unit 70
Input control register (IcR) via internal bus 90
A notification to the effect that monitoring has been activated is written to tt4.

This starts the transmission start timer 102, and thereafter sends out a monitoring signal at short intervals. At the same time, a selection signal (SECT) is supplied to the multiplexer 101 in preparation for reception of the 1g signal from the outside network line.

The priority register (MPR) 15 stores the priority sent out in response to a reception monitoring signal from outside the network, and is initially set to a unique priority assigned in advance to the own station. Note that the unique priority can also be substituted with own station address information.

On the other hand, the one-round priority register 116 stores the priority of the monitoring signal communicated from the other end station in the network, and is initially set to 0. - When the transmission start timer 102 is instructed to send out a monitoring signal, the delimiter generator 1
03, the delimiter explained in FIG. 3 is sent to the signal line SS. When this is completed, the monitoring information transmission register (SS
The contents of SR) l 04 are subsequently sent. This content is the output of the supervisory signal detection circuit 105 (indicating the presence or absence of reception confirmation)
and the priority selected by the multiplexer (MPXz) 107. At the initial stage, the contents of the priority register 115 have a higher priority, so the contents are written to the monitoring information transmission register 104 by the comparator 110. A monitoring signal received from outside the network is taken in via a multiplexer 101, detected by a delimiter detection circuit 105, and its contents are stored in a monitoring information reception register 106. As a result, if the supervisory signal detection pin) SR is 1#, the AND gate 108; OR gate 111 is activated internally, a failure recovery notification is written to the output control register 113, and the internal bus? The network configuration control unit 70 is notified via 0. As a result, network reconfiguration control is executed. If the supervisory signal detection bit SR is '0#', the received priority code PR and one of the priority registers 115, 116 selected by the multiplexer 107 are compared in magnitude by the comparator 109. This fact is written to the output control register 113 by the AND gate 112 and is notified to the transmission control section 60 via the internal bus 90. The transmission control unit 60 transmits the received priority as data to other terminal stations in the network. Note that the contents of the register 115 are rewritten to receive priority only when the received priority is high.

A supervisory signal reception notification from another terminal station in the network is written from the transmission control section 60 to the input control register 114 via the internal bus 90. As a result, the priority level received at this time is written into the series priority register 116.

This priority is determined by the comparator 110.
8 is constantly compared with the contents of register 115.
, the one with higher priority is set in the monitoring information transmission register 104 and transmitted. At this time, if it is detected that the two are equal, this is written into the output control register 113 via the OR gate 111 and notified to the network configuration control section 70 via the internal bus 90. As a result, the network configuration control unit 70 determines that the supervisory signal has completed the loop, and assumes that at least one transmission path has returned to normal, resolves the current configuration and moves on to network reconfiguration operations.

〔Effect of the invention〕

According to the present invention, it is possible to confirm failure recovery between adjacent degenerate networks and to confirm failure recovery of a single loop, so network reconfiguration control can be performed accordingly, resulting in improved system availability.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of a dual ring network having duplexed transmission lines to which the present invention is applied, Fig. 2 is a diagram showing a form of degenerate network transition when multiple transmission failures occur, and Fig. 3 4 is a diagram showing an example of a fault recovery monitoring signal format, FIG. 4 is a diagram showing a hardware configuration of a transmission station, and FIG. 5 is a diagram showing an example of a hardware configuration of a monitoring control section. 1.2...Transmission line, -11-16...Computer/various terminals, 21-26...Transmission station, 31-36...Control unit, 411-416, 421-426...Reception machine,
511-516, 521-526... transmitter, 41.
42... Transmission multiplexer, 43... Reception multiplexer, 50... Central processing unit, 60... Transmission control unit, 70... Network configuration control unit, 80... Interface unit, 90... Internal bus, 100... Monitoring control unit, 101° 107... Multiplexer, 102...
Transmission start timer, 103...delimiter generator, 104
... Monitoring information transmitting register, 105... Delimiter detector, 106... Monitoring information receiving register, 108,1
12...AND gate, 109, 110...Comparator, 111...Or game), 113...Output control register, 114≠2Figure 3 (^) Kanzai tL prayer number 7 Ohmatsu, S'' R: Supervisor 1S U4 IRAPIΔshi E, 7toeR:
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Claims (1)

[Claims] 1. Multiple transmission stations are connected in series in a loop through two sets of transmission lines with different transmission directions, and at the transmission station adjacent to the fault, the transmission line is folded back to isolate the fault location. In a double ring network that uses a degenerate loopback mode to continue data transmission, each terminal station that has transitioned to a mode where the transmission path is looped back uses a bit to set the priority information assigned to its own station and the presence or absence of reception confirmation. The problem can be detected by sending a failure recovery monitoring signal with a A method for detecting recovery from a transmission failure in a dual ring network, characterized by recognizing recovery.