JPS6177448A - Node switching system - Google Patents

Abstract

PURPOSE:To decrease the switching time by giving the same address to a multiplex node and brinding a stand-by system node into by-pass state when an active system node is faulty to apply initial table load. CONSTITUTION:When the active node N1 31 is brought into by-pass state automonusly or from external operation because of a fault of the active system, a node N1 is identified as the by-pass state by a node diagnostic device of a node SV8, the faulty node is disconnected from a data highway L and a stand-by system node 32 is brought into the non-bypass state by the external operation. Then the node SV8 detects on the data highway L that the node N1 is restored. When the node SV8 detects the restoration of a node N32, only the table relating to the node N1 held by the node SV8 is given to a node N1 32 as the initial table load to restart the operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is directed to a multiplexed communication system in which devices each connected to a plurality of station nodes constituting a data highway are integrated into the same system. The present invention relates to a node switching method when configuring active/standby devices.

Generally, a data highway system, as shown in Fig. 3, includes a highway monitoring device (hereinafter referred to as NSP), a highway monitoring node (hereinafter referred to as Sν), and one or more station nodes (hereinafter referred to as NO to Nn). It consists of a data terminal device (TO=
Tn) or communication unit control device (indicated by ccp in this figure) is connected, and data terminal devices (To to Tn) and communication control device (CCP) are connected via a circular transmission path (L). However, in order to improve the reliability of the data highway system, systems have been provided in which the transmission paths are duplicated, the repeaters within the nodes are duplicated, etc.

In the above system, the highway is constantly monitored by Sv, and the ring transmission line (L) or node NO~
When a failure occurs in Nn, the SV automatically switches the ring transmission line (L) or connects the loop bar.

The reliability of the data highway system is ensured by performing directional control or bypass control.

This control is called the automatic control mechanism of the data highway system.

However, if the data terminals (TO to Tn) are connected in a centralized manner, if a failure occurs in the center node, the operation of the system will stop.

In order to avoid this system down, the above node NO.
~Nn will be duplicated, but if nodes are duplicated, the communication path will be changed in the event of a failure or the like.

Also, time slots are given to communicate between the data terminals TO to Tn, but it is necessary to determine in advance which channel of which node will use which time slot for communication. . However, when duplicating nodes, it is not a good idea to allocate time slots twice for working and backup use because this will reduce the transmission efficiency of the ring transmission line (L) by half.

For this reason, the communication path must be changed (i.e., node switching) as necessary.
For example, since it is necessary to load the Sv to each node, there is a problem that the loading takes time. Particularly if the data highway system is large-scale, it will take a long time to recover communication processing from the host computer (indicated by the CPU in Figure 3), so an effective node switching method is needed. was.

[Conventional technology]

FIG. 4 shows a communication control device PL 21. in which host calculation a(H)1 is multiplexed (duplexed in this example). P22
2 constitute the data highway 10, respectively.
31. Connected to N232, PI-Nl is the active system, P
This figure shows a conventional example of node switching when a 2-N2 or standby system is configured.

First, the SV 8 is loaded from an external storage device (not shown), etc.
Load the pre-created "communication table A" shown in Figure 5, divide and reconfigure the contents of the table into information for each node, and perform initial table loading of the table for each node for each node. conduct.

In this case, as in this example, the node N131 is currently used.

If N232 is operated as a backup, SV 8 is used as node Nl 31. N34. N45. N56. N67. , the "communication table A" for each channel is loaded, and the "communication table A" is not loaded into the node N232, or even if it is loaded, the "communication table A" is loaded with the "communication table A" for the node N232. Since table information using the provided channels (C1 to C5) is not included, the table loaded into the node N232 does not include useful information regarding communication.

In the above communication table A, for example, the communication indicated by α is a communication between the communication control device P1 connected to the channel C1 of the node 141 and the data terminal TI connected to the channel C1 of the node N6 in the time slot L1. This indicates that the In the same manner as described below, it can be seen that in this communication table A, communication is performed between a total of seven pairs of data terminals.

The communication table B shows the channels and time slots of each node that can communicate when the backup node N2 becomes active.

Generally, only communication between data terminals defined by communication table A or B is performed.

In the above state, the active node Nl 31. Or, if a failure occurs in the communication control device Pi 21, the node Nl 31 is connected to the data highway (L
) It is necessary to operate the node by separating it from the communication control device P222-node N232.

The disconnection of the node Nl 31 is due to a failure of the node N131, and the disconnection of the node Nl 31 is due to the failure of the node Nl 31.
Each channel (CI) does not capture the data flowing above.

C2,-) data highway (L)
J Pig Data Highway (L) without sending on 10
Transitioning to a bypass state in which data from 10 is simply passed through 1 or the data highway (L) 1
If the transmission path of No. 0 is duplicated, the automatic control mechanism of the data highway system turns back the transmission path (ie, loops back) on both sides of the node N1.

In FIG. 6, the concepts of the bypass [shown in (a)] and loopback [shown in (b)] are shown.

In (a), the node N131 does not process data on the data highway (L) 10, but simply performs the function of relaying data on the transmission path (L) 10.

In (b), nodes on both sides of node N131 [node N232. sV 8) The data is looped back from one side to the other on the duplex transmission line (L) 10, indicating that the node N131 is separated from the data highway (L) 10.

The above-mentioned node bypass is performed by each node's own autonomous function in the event of a failure or by an operator's instruction via the SV 8, and loopback is performed by the SV 8 that detects a power disconnection, etc. of each node. Automatic reconfiguration feature.

Alternatively, it is performed according to an instruction from the operator via Sv.

[Problem that the invention seeks to solve]

In such a conventional method, in order to switch from node N131 to node N232, the SV 8 refers to "communication table B" instead of "communication table A" shown in FIG. 6, and switches from node N232 to node N232. An initial table load must be performed, and an initial table load must be performed again for nodes N34 to N67.

Therefore, in this conventional method, it is necessary to create several types of communication tables for the active/protection nodes, and it takes time for the SV8 to read out the communication tables from an external storage device or the like.

゛There are problems such as the need to perform an initial table load on all nodes each time the nodes are switched, and especially when the data highway system is large-scale, as mentioned above, communication processing from the host computer 1 There was a problem in that it required a long time for recovery.

In view of the above-mentioned conventional drawbacks, the present invention shortens the node switching time when each node fails, restores communication in a short time, and creates a communication table of only 1m, thereby reducing the complexity at the time of creating the communication table. The purpose is to provide a method to remove the .

[Means for solving problems]

The purpose of this is to connect the same device to multiple station nodes, and designate one of the connected devices as the active device.
When communicating with the rest as a backup device, the station node is provided with a switch for switching between bypass state and non-bypass state, or a mechanism for switching by an external signal, and the note addresses of the plurality of station nodes are The same settings are made, and the station node to which the backup device is normally connected is placed in a bypass state, so that in the event of a failure of the active device or a failure of the station node to which the active device is connected, the station node will switch to the data highway. If the system's automatic control mechanism logically disconnects the station node from the data highway, the station node to which the standby device is connected will immediately be placed in a non-bypass state, and if the system is not controlled by the automatic control mechanism above, the failed system will By manually bypassing the station node or disconnecting it from the data highway by turning off the power, the standby station node is placed in a non-bypass state, and the standby station node is incorporated into the data highway. The standby station node receives from the highway monitoring node the same tape/L7 as the communication configuration table held by the faulty station node through the initial table load and resumes communication. This is achieved by the node switching method.

[Effect]

That is, according to the present invention, nodes multiplexed on the data highway (L) have the same node address (for example,
Nl), and when a node in the internal regulation system of the multiplexed node becomes faulty, the faulty node is removed from the data highway (L) by the automatic control mechanism of the data highway system or by an external operation. Disconnect and set the spare note to a non-bypass state by external operation,
When the Sv detects the recovery of the node, it performs an initial table load of the communication table related to the node Nl held by the SV only to the above node, incorporates the node N1 onto the data highway (L), and starts operation. Since it is designed to restart, there is no need to initial table load the communication table for other nodes, and it is possible to switch between active and standby nodes in a short time, and to restore communication in the data highway system in a short time. It has the effect of

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram schematically showing an embodiment of the present invention,
FIG. 2 is a block diagram showing a mechanism for switching a node between a bypass state and a non-bypass state, which is necessary to implement the present invention.

The embodiment in FIG. 1 has the same highway configuration as in FIGS. 4 and 6, but shows an example in which the transmission paths are duplicated. Also, the same symbols indicate the same objects.

In this figure, (a) shows operation by the working node N131, and the backup node 32 is set to the same note address Nl as the working node. state, and from SV 8 onwards, it has completely ceased to exist.

From this state (a), will the active node N131 autonomously enter the bypass state due to a failure in the active system?

Alternatively, when the high-verse state is entered by an external operation, the node diagnosis mechanism of SV8 recognizes the node N1 as being in the bypass state, as shown in (b), and from then on, the node N1 enters the SV state.
8 will be monitored for recovery from the bypass state.

In this state, the standby node 32 is in the bypass state/
When the non-bypass state switching mechanism is operated externally to enter the non-bypass state, the SV 8 switches to the data highway (L) 1 by, for example, polling means, as shown in (c).
0, it can be seen that node N1 has been restored.

When SV 8 detects the recovery of node N132, SV 8
Among the communication tables held by 8, only the table related to node N1 will be initialized to node N132, node Nl 32 will be incorporated into data highway (L) 10, and operation will be resumed. .

At this time, the initial table load has already been completed for the nodes N34 to N67, and the note address N1 remains unchanged even after switching from the working notebook N131 to the backup node N132, so the node Nl 32 is loaded again. By simply performing an initial table load, communications involving the host computer 1 can be restored in a short time.

The mechanism for switching between the bypass state and non-bypass state of each note can be realized, for example, by configuring as shown in the example of FIG.

(a) of this figure shows an example of the configuration of a general notebook assuming a duplex transmission line 1.0.
b) is a diagram illustrating a mechanism in which switching between the bypass state B and non-bypass state of the node is performed by a hardware switch (HSW) or an instruction from the outside.

In this figure, 310 is used to transfer signals inside the node to the transmission line 10.
311 is a signal demodulation circuit (D') for receiving the signal from the transmission line 10 into the node; 312 is a common control unit (CC); 312
0 is the route selection program (EX) for performing the bypass, loopback, etc. 313 is the channel section CI-C
n, 314°315 is the route selection block (EX)
A switching circuit (
SWI, 5W2), 316 is the above hardware switch (HSW), 317 is the host computer (H) 1. Alternatively, it is a switching signal receiving circuit (CX) from outside the node, such as SV 8, or a communication channel for receiving switching messages.

In such a configuration example, the selection of bypass/non-bypass is determined by the common control unit (CCC) as well as the selection of loop
) Route selection block (EX) in 312 3120
Determined by That is, the route selection block (εχ)
3120, the data flow inside the common control unit (CC) 312 and the switching circuit (Ski) 314.
(SV2) It is implemented by selecting 315 human power.

For example, ■Q■ or ■゛)■′ indicates the data flow during normal operation, ■)■゛ or ■゛9■ indicates the flow during loop hacking, and ■ indicates the case of bypass. , ■ indicates the flow of data during loopback and bypass.

The factors that determine bypass/non-bypass are as follows:
Judgment may be made by an instruction from the SV 8 transmitted via the transmission line 10 or by self-diagnosis at each node.

In such a node configuration, the hardware switch (HSW) shown in (b) 316. Alternatively, add one or both of the external switching signal receiving circuits (CX) 317 and change the logic state of both circuits to the route selection block (EX) 3.
By adding this to the bypass/non-bypass state selection condition in step 120, it is possible to add a bypass/non-bypass state indication function from outside the node to each note.

Note that the switching signal receiving circuit (CX) may be a communication channel for receiving the switching message, and in this case,
This can be accomplished by using one of the notebook's inherent communication channels for this specific purpose.

[Effects of the Invention] As explained above in detail, the node switching method of the present invention gives the same node address (for example, Nl) to the nodes multiplexed on the data highway (L),
When a node in the internal system of the multiplexed nodes becomes faulty, the faulty note is disconnected from the data highway (L) by the automatic control mechanism 5 of the data highway system or by an external operation, and the node in the backup system is disconnected from the data highway (L). When a node is placed in a non-bypass state by an external operation and Sv detects recovery of the node, the node N held by the Sv
The communication table for No. 1 is initialized only to the above node, and the operation is resumed by incorporating Node No. 8 on the data highway (L). Therefore, the initial table of the communication table for other nodes is There is no need for table loading, switching between active, active, and standby nodes can be done in a short time, and data highway system communications can be restored in a short time.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing an embodiment of the present invention. FIG. 2 is a diagram showing an example of a configuration for switching between a bypass/non-bypass state. FIG. 3 is a diagram showing the configuration of a general data highway system. FIG. 4 is a diagram illustrating a conventional node switching method. FIG. 5 is a diagram showing an example of a communication table used when switching nodes according to the conventional method. Figure 6 shows bypass and loopback at each node.
This is a diagram explaining regret. In the drawing, ■ is the host computer (11). 21.22 is a communication control device (PI, P2). 31.32.4-7 are station nodes (Nl-N6
) 38 is Highway Superintendent '6 Shino F' (SV). 310 is an S signal modulation circuit (M), and 311 is a signal decoder circuit (D). Reference numeral 312 indicates a control unit (CC). 313 is Chiyafubu (C1-Cn). 314 is a switching circuit (SWI). 315 is a switching circuit (SW2). 316 is Bardow 1. As Inochi (IIsW). (Consideration 17) 42. (L-1 receiving circuit (CX)
. 3120 is a route selection lock (IEX). IO is Take' Highway (ring transmission line) (L). TO~Tn are data terminal devices. 11. Don't show it.杢2 T3 41-5 Title T7
Work 5 Figure i ↓ Table Ha

Claims (1)

[Claims] A highway monitoring node and a plurality of station nodes each having a plurality of device connection channels are connected via a circular transmission path, and the highway monitoring node transmits a communication configuration table created in advance to each station node that can operate normally. Then, the initial table is loaded through the above circular transmission line,
In a data highway system that can thereafter start communication between devices connected to the channels defined in the communication configuration table, the same device is connected to each of the plurality of station nodes, and the connected devices are connected to each other. When communicating with one of the devices used as a working device and the rest as a standby device, the station node is provided with a switch for switching between a bypass state and a non-bypass state, or a mechanism for switching by an external signal. The node addresses of multiple station nodes are set to be the same, and the station node to which the above-mentioned backup device is normally connected is placed in a bypass state. If the station node in question is logically disconnected from the data highway by the automatic control mechanism of the data highway system, the station node to which the backup device is connected is immediately placed in a non-bypass state and controlled by the automatic control mechanism. If not, by manually bypassing the faulty station node or disconnecting it from the data highway by cutting off the power, the standby station node can be placed in a non-bypass state.
The standby station node is incorporated into the data highway, and the incorporated standby station node receives the same communication configuration table as the communication configuration table held by the failed station node from the highway monitoring node. A node switching method characterized by receiving an initial table load and restarting communication.