JPH03195145A - Transmission line control system for ring network - Google Patents

Abstract

PURPOSE:To separate and add a node without being conscious of the abnormality of a transmission line by each node and to reconstitute the transmission line at high speed by executing a token generating instruction and a token erasing instruction to the erasing of a token and an adjacent node. CONSTITUTION:A connecting mode switching means 13, transmission/reception control part 14 and configuration control part 15, etc., are provided. When a node 10 is separated from a ring network, a connecting mode is switched after receiving the token and the generation of the token is instructed to the adjacent node. Corresponding to this instruction, the token is generated at the adjacent node and an operation is continued. When the node is added, the erasing of the token is instructed to the adjacent node and corresponding to this instruction, the token is erased. When it is informed that the token is erased, corresponding to this information, a subscriber desired node switches the connecting mode of the transmission line, newly transmits the token and continues the operation. Thus, when the node 10 of the ring network is separated from the system or added not by a fault but by an intension, the transmission line can be speedily reconstituted without erasing the token.

Description

[Detailed Description of the Invention] [Summary] A plurality of nodes are connected through a duplex ring-shaped transmission path,
Concerning a transmission path control method for a ring network that performs access control using tokens.

The purpose of this invention is to provide a method for quickly reconfiguring transmission paths without causing token loss when a ring network node intentionally leaves or joins the system rather than due to a failure.

When a node leaves the network, when the node #1 that wishes to withdraw receives a token, it erases it and switches to a mode in which the transmission path is looped back to both adjacent nodes, and there is no signal on the transmission path from both adjacent nodes. After detecting this, a token generation instruction is sent to one adjacent node, and the adjacent node detects no signal on the transmission path and switches to a mode in which the transmission path is looped back, and then a token generation instruction is sent from the node wishing to leave. When the node receives the token, it sends a new token to continue normal operation, and when the node joins the network, the node that wants to join sends a token deletion instruction to the adjacent node, and after the adjacent node detects the control signal, It erases the received token and sends a token erasure notification to the joining node, and when the joining node detects the token erasure notification, it switches the connection state of the transmission path from the loopback state to the normal transmission state and inserts a new token. Configure to continue operation by sending.

[Industrial Application Field] The present invention relates to a transmission path control system for a ring network in which a plurality of nodes are connected through a duplex ring-shaped transmission path and access control is performed using tokens.

With the advancement of office automation (OA), local area networks have become widespread. A token ring network that performs token passing on a ring-shaped transmission path is well known as a typical system of such a network. However, ring networks have the property that the entire network goes down due to failure of some nodes.
Usually, the system is configured with a double ring, and when a failure occurs, the transmission path is looped back at the nodes at both ends, and degenerate operation is performed as a single ring.

However, if a node becomes unable to operate normally due to a failure, etc., it takes time for other nodes to detect the condition, reconfigure the ring, and make it operational again, resulting in the network not being able to operate during that time. There is a need for improvement.

[Prior Art] FIG. 7 is an explanatory diagram of a conventional duplex ring network.

A in FIG. 7 shows the connection configuration during normal operation. In this case, the token is transmitted through the ring of the active transmission line, and the backup line is not used. If normal operation becomes impossible in this state due to a failure or the like, the token will be lost.

When tokens run out in this way, a process is performed to detect the faulty node, disconnect the node, and issue tokens.

The connection configuration at the time of a failure is shown at the beginning of FIG. This shows the connection status when loopback is performed using the transmission path, which indicates that nodes b, a,
d constitutes a token ring network.

However, there are conventional methods for recovering when normal operation is no longer possible due to a failure or the like.

■When a node adjacent to the failure point detects an abnormality by detecting a signal disconnection, the node changes the transmission line connection status, and the transmission line is turned around before and after the failure part.
Isolate the abnormal part from the network.

■This causes the token to be lost, but when the timer detects that the token has not been circulated to each other node after a certain time interval, a token reclamation node determination procedure called the claim token process is executed. .

In this procedure, each node generates a token request (claim), compares the node number (address) included in the received token request with its own number, and determines which node has higher priority (e.g. , giving priority to the youngest number) is lower, the request is passed, and if it is higher, the request is discarded. With this,! Also, only a single request generated from a node with a high priority returns to the node that generated the request. In this way, normal operation is resumed by circulating the only token.

[The invention is trying to solve the problem II! ! ] According to the conventional method described above, the process to generate a token normally requires a long timeout period and many associated software processing steps, making it difficult to resume normal operation after a failure occurs. The disadvantage is that it takes a long time to complete the process.

Moreover, it may not be due to a failure, but a node wants to leave the system (network) by turning off the power, or when a node newly joins by turning on the power.

Since the exact same control ff1 as in the case of a failure occurs (the connection is temporarily disconnected in order to join and connect a new node to the previously connected transmission path), the nodes in the network will not be able to turn on the power. -There was a problem that the entire network would go down every time it was turned off.

An object of the present invention is to provide a method for quickly reconfiguring a transmission path without causing token loss when a node of a ring network intentionally leaves or joins the system rather than due to a failure.

[Means for Solving the Problems] FIG. 1 is a diagram showing the principle configuration of a node that executes the control method according to the present invention, FIG. 2(a) is a diagram explaining the principle of node withdrawal according to the present invention, and FIG. 2(b) FIG. 2 is a diagram explaining the principle of node joining according to the present invention.

In FIG. 1, 10 is a node, 11 is a control signal detection means, 12 is a control signal transmission means, 13 is a connection type switching means, 14 is a transmission/reception control section, 141 is a token control means, 1
5 is a configuration control unit that controls node withdrawal and joining; 16A;
, 16B represent transmission paths to adjacent nodes, 17A and 17B represent transmission paths to other adjacent nodes, and transmission paths A and B represent the operational system during normal operation of the same duplex ring as before. It represents a backup system, and the transmission direction is the opposite direction.

Further, although an example of a double ring network will be described in FIGS. 1 to 2, a star-shaped ring via a concentrator can be constructed based on the same principle.

In the present invention, when a node leaves the ring network, after receiving a token, it switches the connection form and instructs the adjacent node to generate a token, and the adjacent node generates a token in response to this, continues operation, and joins. When doing so, adjacent 7
When the node is instructed to erase the token, the adjacent node erases the token in response, and notifies the node that it has been erased, the node wishing to join switches the connection state of the transmission path accordingly and sends a new token. The system will continue to operate.

[Operation] The principle of the transmission line control system of the present invention having the configuration shown in FIG. 1 will be explained using FIG. 2(a) and FIG.

In FIG. 2(a) and FIG. 2(b), a
-d represents a node configuring the ring network.

Each of (A) to (E) shows the connection form of the transmission path within each node corresponding to the passage of time.

When a node leaves, as shown in (b) of Figure 2(a), when the only token is circulating within the ring network in the normal operating state (using the A-system ring),
Assume that it becomes necessary to remove node C from the system. At this time, an instruction to leave is input at node C.

When the node C in FIG. 2(a) is instructed to leave, the configuration control unit 15 in that node is activated to execute the leave. The configuration control unit 15 instructs the transmission and reception control unit 14 to erase the token, and when the token is received as shown in FIGS. 2(a) and (b), the token control means 141 of the transmission and reception control unit 14 detects The node is deleted and the configuration control unit 15 is notified. The configuration control unit 15 switches the connection type switching means 13 to change the connection of the transmission line within the node C to loopback to the adjacent nodes b and d, as shown in FIG. 2(a)(c). ) to form own node C
disconnect from the network.

On the other hand, when adjacent node b or d detects no signal from node C, the transmission/reception control unit 14 notifies the configuration control unit 15 . Accordingly, the configuration control section 15 controls the connection type switching means 13.

As shown in nodes b and d in (d) of FIG. 2(a), the nodes are turned back and changed to a loopback state to complete the transmission path reconfiguration. In this state, node C.

Control signal transmitting means 1 to either adjacent node b or d
The token sending instruction is performed from 2 ((d) in Fig. 2 (a)).
(then sent to node b).

When this is detected by the control signal detection means 11 of node b,
Notify the configuration control unit I5. Configuration control unit 15 of node b
When receiving this, it instructs the token control means 141 of the transmission/reception control unit 14 to transmit the token, and (
As shown in e), a token is transmitted from node b to node a.

This token is attached to the newly reconfigured ring d, a.

traverse the network along b.

Next, when adding a node, when node C leaves the ring network and the token is circulating among nodes d, a, and b, as shown in (a) of Figure 2(b), node C is added. An input of a desire to join for integration is input to the configuration control unit 15 of the node C.

Then, the configuration control unit 15 controls the control signal transmitting means 12 to issue a token deletion instruction to one of the adjacent nodes b and d, for example, node b.

When this token erasure instruction is detected by the control signal detection means 11 of the adjacent node b, it is notified to the configuration control unit 15 of the node b. The configuration control section 15 instructs the token control means 141 of the transmission/reception control section 14 to erase the token. When the node b receives the token, the token control means 141 erases it and notifies the configuration control section 15 that it has been erased. Upon receiving this, the configuration control unit 15 controls the control signal transmitting means 12 to transmit a token erasure notification signal (
(See (b) in Figure 2 (b)).

When node C detects this control signal by the control signal detection means 11, it transmits an idle signal for incorporating its own node from the control signal transmission means 12 to the adjacent nodes b and d (see (c) in Figure 2). ).

When nodes b and d detect an idle signal from adjacent node C by control signal detection means 11, they transmit an idle signal to adjacent node C from control signal transmission means 12 of each node to start up a transmission path. (See (d) in FIG. 2(b)), nodes b, c, and d detect that the connection process with the adjacent node is completed in the configuration control unit 15 by transmitting and receiving such signals, and each node The connection mode switching means 13 of the node C is driven to change the connection mode of the transmission path, and the network finally becomes as shown in (e) of FIG. A token is sent from the means 141, and the token is sent to the reconfigured rings d, a, b.

C and normal operation resumes.

[Example] Fig. 3 is a configuration diagram of an embodiment of a node according to the present invention, Fig. 4 is a control flow diagram for node withdrawal, Fig. 5 is a control flow diagram for node joining, and Fig. 6 is a diagram showing the connection form of a transmission path. FIG. 3 is a diagram showing the setting relationship of each selector.

In FIG. 3, 30 is a node, 31. 33 is a control code detection unit that detects control codes for token erasure instructions, token erasure notifications, and token generation instructions from received signals; 32;
．． 34 is a control code transmitter that transmits each of the control codes to the transmission path; 35 is an information reception controller; 36 is a buffer memory that stores transmitted and received information; 37 is an information transmission controller;
38 is the control of the transmission right (token), selectors SO to S5
(control unit: including the functions of the configuration control unit shown in FIG. 1).

39 is a processor bus (including control lines), R is a receiving circuit, T is a transmitting circuit, 5O-35 is a selector, and SO is for inputting information (including tokens) to be transmitted from this node to the transmission path. selector.

31 to S3 are switches for changing the connection form of the transmission line, and S4 and S35 are switches to be changed when transmitting a control code.

It is assumed that the network configuration and node names (a-d) are the same as in FIG. 2 above, and that each node is initially using the active transmission path (ring A).

At this time, the connection form of the transmission path of each node is in the state of "transmission via system A" as shown in (■) in FIG. 6, and the selector 5l-
53 is set as shown in the figure. 51=O shown in the setting state of the selector is "0" input to the selector Sl shown in FIG.
” and “1”, the input “rO” is selected. In addition, in the diagram showing the connection form of the transmission path in FIG. 6, the block indicated as "control section" represents a combination of an information transmission control section and a reception control section.

Regarding the case where node C leaves (minute #I) in this state, the control flow for leaving shown in FIG. 4 will be described with reference to FIGS. 3 and 6. The entire operation of 1M desorption (separation) is as described with reference to FIG. 2(a).

When node C performs H-departure, when a control signal (command, etc.) for requesting withdrawal is entered manually from a keyboard (not shown), it is supplied to the processor 38 and control of withdrawal is started. Then wait for the token to be received (40 in Figure 4).
), when the reception control section 35 receives the token, the transmission control section 37 performs an operation of transmitting an idle signal via the selector SO and erases the token. (41 in Figure 4
), then at node C, selectors SL and S in FIG.
2 and S3 to the setting state shown at the right end of ■ in Fig. 6,
The connection form of the transmission path is set to a "separated" state in which each node b and node d are looped back (42 in FIG. 4).

The outputs of this node C to the transmission lines A and B of both systems are in a no-signal state, and the control code detection units 31.3 at nodes b and d
3, detects no signal (carrier not detected) from node C. When this state is detected, each node b
, d, the connection form of the own node is loopback in system A (state shown in ■ in Figure 6) and loopback in system B (state 6).
Change the state to ■ in the figure). As a result, the network enters a loopback operation state with nodes B and D, and node C is disconnected from the system (
43.44 in Figure 4).

At this time, in node b, selectors Sl, S2. S3 is controlled to select inputs of 0 and 0.2, respectively, and at node d, selectors Sl, S2 . S3 respectively l, 2.
It is controlled to select the input of O.

As a result of this switching, when node C detects no signals from adjacent nodes b and d using control code detection units 31 and 33,
Under the control of the processor 3B, one of the adjacent nodes b and d,
In this example, the control code transmitter 32 sends a control code for a token sending instruction to the node b at 45 in FIG.
), the separation of node C is completed. The token sending instruction code is.

For example, using a redundant code such as a 435B code (a code with 1 redundant bit added to a 4-bit code),
One of the codes not assigned to data may be assigned to this control information, or a control frame may be sent.

When this flUI code is decoded by the B-system control code detection unit 33 of the node b and it is detected as a token sending instruction, the token is transmitted from the transmission control unit 37 via the selector SO (46 of the fourth rjA), Then, this token goes around the ring along the B line excluding node C, and normal operation is resumed.

Next, the control flow of node incorporation (joining) shown in FIG. 5 will be explained with reference to FIGS. 3 and 6.

Note that the entire operation including vA (subscription) is as explained in FIG. 2 (b).

As shown in ■ in Figure 6, node C is in an isolated state, adjacent node b is in a loopback state in system A (state shown in ■ in Figure 6), and adjacent node d is in a loopback state in system B (state in 6), when node C is embedded (
When the user inputs a request for joining, a control code for instructing token deletion is forcibly transmitted to the adjacent node b or C according to an instruction from the processor 38. In this example, the control code is transmitted from the control code transmitter 32 to the node b via the selector S4 (50 in FIG. 5).

At node b, this signal is sent to the B-system control code detection unit 33.
decodes it and recognizes that it is a token deletion instruction. Then, wait for token reception from A system (51 in Figure 5).
), upon receiving it, it is erased (52 in Figure 5), and immediately the control code transmitter 34 for output to the A system transmits a token erase notification code (this code is the same as the token erase instruction code). ) is forcibly transmitted (53 in Fig. 5).

When the node C detects this signal in the control code detection unit 31 of the A system, the output direction selector S4. From the control code transmitter 32.34 via S5, the adjacent node b,
An idle signal for starting the transmission path (54 in FIG. 5) is transmitted to d. Adjacent nodes b and d recognize that the transmission path with node C has become normal when detected by their respective control code detection units 33.31, and transmit the signals from their control code transmission units 34.32 to the nodes via selectors S5 and S4. After transmitting an idle signal to C as a response signal, the transmission path configuration is a state in which transmission is performed using A system (■ in Figure 6)
(55°57 in Figure 5).

In node C, this idle signal is detected by the control code detection units 31.33 of both systems, and when it is confirmed that the signals from both systems are normal, the state of the own node is transmitted in system A (6th (56 in FIG. 5) to complete the incorporation into the network. Thereafter, the node C transmits the token from the transmission control unit 37 (58) in FIG.
Normal network operation resumes.

In both of the operations of leaving (separating) and incorporating (joining) a node as described above, no abnormality in the transmission path is detected at any node other than the node in question, so it is far more effective than the conventional reconfiguration of the transmission path. [Effects of the Invention] According to the present invention, nodes can be detached and joined in a token ring network without making each node aware of abnormalities in the transmission path. Transmission path reconfiguration can be achieved much faster than the failure recovery time of . Also, withdrawal/
Since the token does not exist while the subscription is being processed, it is guaranteed that the transmission path is not used by anyone.
This prevents transmission frames from being lost or data from being erroneous, and wasteful retransmissions can be prevented.

7 is a diagram showing the relationship between the connection form of the transmission line and the settings of each selector, and FIG. 7 is an explanatory diagram of a conventional example.

In Fig. 1, 10: Node 11: Control signal detection means 12: Control signal transmission means 13; Connection type switching means 14: Transmission/reception control section 141: )-Kun control means 15: Configuration control sections 16A, 16B: Connection to adjacent nodes Transmission lines 17A, 17B
:Transmission path to other adjacent nodes

[Brief explanation of drawings]

Claims (2)

[Claims] (1) In a ring network transmission path control method in which multiple nodes are connected through a duplex ring-shaped transmission path and access is controlled using tokens, when a node leaves the network, the node that wishes to leave receives a token. Then, it erases this and switches to a mode in which the transmission path is looped back to both adjacent nodes, and after detecting no signal on the transmission path from both adjacent nodes, it sends a token generation instruction to one adjacent node. , The adjacent node detects the no signal on the transmission path and switches to the mode of looping back the transmission path, and then, upon receiving a token generation instruction from the node wishing to leave, transmits a new token and continues normal operation. Characteristic ring network transmission path control method. (2) In a ring network transmission path control method in which multiple nodes are connected via a duplex ring-shaped transmission path and access is controlled using tokens, when a node joins the network, the node wishing to join connects to the adjacent node. After detecting the control signal, the adjacent node erases the received token and sends a token erasure notification to the node desiring to join. When the node desiring to join detects the token erasing notification, it A transmission path control method for a ring network characterized by switching the connection state from a return state to a normal transmission state and continuing operation by transmitting a new token.