JPH0712173B2 - Node control system - Google Patents

Description

The present invention relates to a modified U-link system node control system, and more particularly to a highly reliable node control system.

[Conventional technology]

In the conventional method of connecting multiple nodes and transmitting data in the opposite directions to the upstream and downstream transmission media, as shown in Fig. 10, nodes L _{1 to} L _N and data are input to each node. and an output data terminal units E ₁ to E _N. A clock is generated at node L ₁ , passes through each node of the upstream transmission line, and the transmission line turns back at the final node L _N (referred to as the most upstream node) and becomes the downstream transmission line and becomes node L ₁
To reach the end. At this time, each node multiplexes and supplies the data from each data terminal unit to the upstream transmission line, and supplies the data from the downstream transmission line to each data terminal unit.

Now, let us examine the situation when the transmission line connecting the nodes L ₂ and L ₃ is disconnected at the connection point X ₃ . As shown in Fig. 11, the connection point was simply disconnected, but unless self-recovery work was performed within the node, the upstream and downstream transmission lines would be isolated and data transmission would be impossible. Will stop. However, in reality, the node L ₂ has a function of short-circuiting the signals input / output to and from the up and down transmission lines, so that the link is established only by the nodes L ₁ and L ₂ and data can be exchanged. . On the other hand the node L ₃ is of at ~L _N in the node L ₃ are provided with the function of the clock is generated, the node L ₃ ~L each data terminal units E ₃ ~ through transmission lines upstream and downstream between the _N E _N of data between each other input and output can and will link is established.

However, in this case, since the conventional link is divided and the link is established in each sub-link, it is impossible to input / output data between the sub-links.

[Problems to be solved by the invention]

As described above, the problem of the conventional technique to be solved by the present invention is that a link is established for each of the divided links when a failure occurs in the transmission medium and the link is broken. Was not replaced,
Therefore, in the worst case, it may not be useful at all.

Therefore, an object of the present invention is to provide a node control method that solves the above drawbacks.

[Means for solving problems]

The node control method of the first invention of the present invention detects the presence or absence of respective clocks from upstream and downstream data received from upstream and downstream transmission media, and detects the node number of a node in clock mode. Detecting the mode of the preceding node from the upstream data received from the upstream transmission medium, the presence or absence of the detected clock, the node number of the node in the clock mode and the mode of the preceding node The node selects any one of the clock mode, the loopback mode and the repeater mode, and the data input from the data terminal unit is multiplexed to the upstream transmission medium and transmitted, and received from the downstream transmission medium. Out of the data, the required data of the data terminal unit is output and the signal indicating the clock generation node number is output. Constructed and a that can generate a clock signal, including.

〔Example〕

Next, the present invention will be described in detail with reference to the drawings illustrating an embodiment.

1 is an explanatory view showing node transition control of the present invention, FIG. 2 is a chart showing transition conditions of the node of the present invention, FIG. 3 is a chart showing mode transition status of the node of the present invention, FIG. 4 (A)-(c) is explanatory drawing which shows the mode of the node of this invention, FIG. 5 is a block diagram which shows the 1st basic structure of the node of this invention, FIG. 6 is the 2nd of the node of this invention. FIG. 7 is a block diagram showing the basic configuration, FIG. 7 is a block diagram showing the basic configuration of the node of the present invention, FIG. 8 is a block diagram showing an example of the configuration of a modified U-link using the node of the present invention, and FIG. It is a block diagram explaining operation | movement at the time of abnormality of the modified U link using the node of this invention.

An outline of an embodiment of the present invention will be described.

Referring to FIG. 8, one embodiment of a modified U-link system using the present invention is an upstream transmission medium or upstream transmission line 100, a downstream transmission medium or downstream transmission line 101, and nodes N _{1 to} N.
And _N, is constituted by corresponding to each of the nodes and the data terminal unit E ₁ to E _N for inputting and outputting data, upstream transmission line 10
0 and the downlink transmission line 101 respectively connect the nodes N _{1 to} N _N in a ring shape. In such a case, the clock generator 102 of any one of the nodes, for example, the node N ₁ is activated to supply the clock signal to the upstream transmission line 100. The signals of the upstream transmission line that are input at the same time are returned as they are and output to the downstream transmission line.

The data output from the data terminal unit is multiplexed and output from each corresponding node to the upstream transmission line, and the data output from the downstream transmission line is output from each node to the corresponding data terminal unit. Next is the ninth
The situation when the transmission line is disconnected will be described with reference to the figure.
For example, if the transmission line between nodes N ₃ and N ₄ is disconnected at connection point X ₁ , a clock is generated from node N ₄ and node N ₁
Becomes a normal repeater, and the signal of the upstream transmission line output at the node N ₃ is directly connected to the downstream transmission line and starts operating in the same form as the conventional U-link. In order to perform such an operation, each node detects the situation, and the mode of the node transits according to the result to generate the clock.

Next, the mode operation of the node of the present invention will be described.

First, three modes of the node will be described. Commonly necessary operations for viewing FIGS. 4 (a) to (c) are to supply input data to an upstream transmission medium, that is, an upstream transmission line, and to supply output data from a downstream transmission medium, that is, a downstream transmission line. That is. First mode shown in FIG. 4 (a) is (are connected to the node N _N-1 side to the node N _N shown in example FIG. 8) of the called repeater mode clock source side up transmission Data received on the medium, that is, the upstream transmission line (called upstream data from the downstream node) is output to the upstream transmission line as it is (transmitted to the upstream node) and data received from the downstream transmission line (called downstream data from the upstream node). ) is output to the clock source side (e.g., the eighth is connected to the node N _N-1 side to the node N _N shown in FIG.) downstream transmission medium or downstream transmission line (sends to the downstream node) those Is. The second mode shown in FIG. 4 (b) is called the loopback mode, in which the upstream data from the downstream node is directly transmitted to the upstream node and is also transmitted to the downstream node as downstream data. Although downlink data is detected, it is not captured and is interrupted at this node. The third node shown in FIG. 4 (c) is called a clock mode and generates a clock from its own node, does not send it as upstream data to the upstream node, and loops back the upstream data from the downstream node as downstream data. It is sent to the node.

In addition, the contents of detection of the status of the link held by each node for the transition between these modes will be described. The first detection content is to detect the presence or absence of the clock of the upstream transmission line, and the second detection content is to detect the presence or absence of the clock of the downstream transmission line. The third detection content is to detect the clock generation source (node number, etc.), and the fourth detection content is to detect whether the immediately downstream node (that is, the preceding node) is in the loopback mode. Is.

Next, the main conditions of node transition for recovery such as disconnection of transmission line are shown. First, when there is no clock on the upstream transmission line, the detected node is in clock mode; second, when there is no clock on the downstream transmission line in repeater mode, the node is in folding mode; third, folding mode Sometimes if the downstream transmission line has a clock, its own node becomes a repeater node. Fourth, in the third case the own node becomes the clock mode when the direct downstream node is in the loopback mode. Fifthly, at the clock mode. When only the clock of the downlink transmission line is not available, the loop mode is set. In the sixth case, if the direct downstream node is the loop mode, the local node remains in the clock mode. Seventh, in the clock mode. When there are clocks for the upstream and downstream transmission lines and there is a clock originating from another node on the upstream transmission line, the repeater mode is entered. Immediately downstream node when the seventh is a condition for transition remains to be a node of the clock mode when the folded mode. FIG. 3 shows the transition conditions of these nodes in more detail, and FIG. 1 shows the contents of the transition control of the nodes under these conditions. The symbols 1A and 1B in Fig. 1 and 2 ...
The symbol "..." indicates the control condition. Further, FIG. 3 shows the modes before and after the transition in this case corresponding to each condition. The present invention can be implemented by the above method.

Next, an example of these operations will be described with reference to FIGS.

In FIG. 8, assuming that the upstream and downstream transmission lines connecting between the node N ₃ and the node N ₄ are disconnected, first, the clock output from N ₁ is upstream at the nodes N ₂ and N ₃ . Even if the clock is transmitted to the clock transmission line, the clock is not detected on the downstream transmission line. In addition, no clock is detected in the upstream and downstream transmission lines at the nodes N _{4 to NN} . further,
At the node N ₁ , the clock input from the upstream transmission line is not detected. At this time, the nodes N ₂ and N ₃ are
Although the loop mode is set depending on the transition condition of the IC, the operating time of the node is generally different, so that the node that transits earlier will dominate the node that is delayed.

In this case, when the node N ₃ enters the loopback mode, the node N ₂ detects clocks on the upstream and downstream transmission lines.
It remains in repeater mode under the transition condition of 1F in Fig. 2.
However, when the node N ₂ is in the loopback mode, the node N ₃ has a clock in the upstream transmission line but no clock in the downlink transmission line, and the direct downstream node N ₂ is in the loopback mode. Under the transition condition of, the node N ₃ is in the folding mode. Next, since the node N ₂ has clocks in the upstream and downstream transmission lines and the direct downstream node N ₁ is in the clock mode, the node N ₂ is in the repeater mode under the transition condition of 2F in FIG.

On the other hand, in the nodes N _{4 to NN} , there is no clock in the upstream and downstream transmission lines, so the node with the fastest transition operation is in the clock mode under the transition condition of 1A in FIG. At this time, nodes up to the downstream of the node in the clock mode, for example, the node N _N , are kept in the repeater mode because there are clocks of the upstream and downstream transmission lines. Next, among the nodes upstream of the node that has entered the clock mode, the node that has completed the transition operation enters the clock mode. In this way, the operation is performed downstream, and finally the node N ₄ is in the clock mode. Therefore, the node in the clock mode sandwiched between the nodes in the repeater mode has the clocks in the upstream and downstream transmission lines, the direct downstream node is the repeater, and the other nodes are still detected. _All of them including ₁ are in repeater mode depending on the transition condition of 3F in FIG.

Therefore, the node N ₄ is in the clock mode, the node N ₃ is in the loopback mode, and all the other nodes are in the repeater mode to complete the link as shown in FIG.

Next, an embodiment of the present invention will be described focusing on its configuration and operation.

As shown in FIG. 8, nodes N _{1 to} N _N of a modified U-link using the node of the present invention are an upstream transmission medium, that is, a transmission line 100 and a downstream transmission medium, that is, a downstream transmission line 101, which are composed of lines such as coaxial cables. Connect and data terminal unit D ₁
Each data from to D _N through node N ₁ to N _N is supplied to the upstream transmission line 100, the data from the downstream transmission line 101 respectively provided to the node N ₁ to N _N corresponding through terminal unit D ₁ to D _N To be done. Each node is configured so that mode transitions as shown in FIG.
The first basic configuration is shown in FIG.

Next, the configuration and operation of the first basic configuration of the node of the present invention will be described.

As shown in FIG. 5, the signal of the upstream transmission medium is the upstream transmission line 111.
From the node 1A to the upstream transmission line 112, the signal of the downstream transmission medium from the downstream transmission line 113 is output to the downstream transmission line 114, and the transmission line is configured by a coaxial cable or a biaxial system. Data is output from the data terminal unit 2 to the up transmission line 112 through the data inserter 17, and the data output from the down transmission line 113 is also supplied to the data terminal unit 2.

Next, the node 1A is connected to the clock detectors 11 and 13 and the node detector.
12, control logic 14, clock generator 15, mode inserter 16, data inserter 17, changeover switch SW _1A / SW
It is equipped with _1B and SW ₂ .

First, the clock detectors 11 and 13 detect the presence or absence of clocks on the upstream and downstream transmission lines 111 and 113, respectively, and input the results to the control logic 14, and the node detector 12 detects the clock generation node from the upstream transmission line 111. (That is, the clock source node) is detected and whether the immediately downstream node (node at the previous stage) is in the folding mode or another mode is detected, and the result is input to the control logic 14.

The mode inserter 16 inserts a recognition signal into the frame of the transmission data when the own node is in the loopback mode, and the data inserter 17 transfers the data from the data terminal unit 2 to the transmission data of the upstream transmission line. Is to be inserted in the frame.

On the other hand, the operation of the control logic is to activate the changeover switches SW _1A , SW _1B and SW ₂ (to turn them on),
First, when the changeover switch is not operated, it is in the repeat mode. Next, when the changeover switches SW _1A and SW _1B are activated (turned on), the clock output from the clock generator 15 and a signal indicating that its own node is the clock source are transmitted through the changeover switch SW _1A to the upstream transmission line. It is output to 112, the input of the upstream transmission line 111 is output to the downstream transmission line 114 through the changeover switch SW _1B , and the mode of the own node becomes the clock mode. In addition, the changeover switch SW ₂ has operated O
When the N state, the output mode of the own node is output to the downstream transmission line 114 through the changeover switch SW ₂ at the same time of the uplink transmission line 112 becomes folded mode, labeled signal that the node is a folded modes Mode inserted It is output into the frame of the transmission data of the upstream transmission line 112 through the device 16.
Further, here, only the indicator signal indicating that the signal to the mode inserter is the folding mode is output in the frame of the transmission data of the upstream transmission line, but the indicator signals may be identified by identifying the three modes. The operation of the control logic 14 based on the operation of the node as described above is determined by the mode transition based on the presence or absence of the clocks of the upstream and downstream transmission lines in FIG. 3 and incidental conditions.

Next, the second basic configuration and operation of the node of the present invention will be described.

As shown in FIG. 6, the signal of the upstream transmission medium is the upstream transmission line 12
Input from 1 to the node 1B, becomes an electric signal through the opto-electric converter 18, is internally processed and becomes an optical signal again through the electro-optical converter 19, and is output to the upstream transmission line 122, and the transmission medium, that is, the transmission line is an optical fiber or the like. The signal is an optical signal. Similarly, the signal of the downlink transmission medium is input to the node 1B from the downlink transmission line 123, becomes an electric signal through the opto-electric converter 20, is internally processed, becomes an optical signal again through the electro-optical converter 21, and is output to the downlink transmission line 124. To be done. The node 1B includes the clock detectors 11 and 13, the node detector 12, the control logic 14, the clock generator 15, the mode inserter 16, the data inserter 17, and the changeover switch SW _1A.
SW _1B / SW ₂ , photoelectric converter 18/20, and electro-optical converter 19.2
It has 1 and. Other than the configuration and operation of the opto-electric converters 18 and 20 and the electro-optical converters 19 and 21 described above, the second basic configuration and operation of the node of the present invention is the same as that of the first basic configuration. .

Since the second basic configuration of the node of the present invention uses the optical fiber as the transmission medium, the transmission medium has extremely strong resistance to electromagnetic interference and can be used in a severe environment.

Next, the configuration and operation of the first embodiment of the node of the present invention will be described.

As shown in FIG. 7, the signal of the upstream transmission medium is the upstream transmission line 121.
From the optical switch 22 and the optical-electrical converter 18 into an electrical signal, which is processed inside the node 1C to become an optical signal again through the electrical converter 19 and is output to the upstream transmission line 122 through the optical switcher 22. To be done. The transmission medium is an optical fiber and the signal is an optical signal.
22 is an operation signal that is output in response to an abnormal operation of the node 1C, because when the abnormal operation of the node 1C occurs, the input / output of data of the node is sacrificed to continue the operation of the link.
The switching node 1C is excluded by 131 and 132, which is generally performed at the same time as the switching of the downlink transmission medium described below. The signal of the downlink transmission medium is input to the node 1C from the uplink transmission line 123, similarly to the uplink transmission medium.
It becomes an electric signal through the optical switch 23 and the opto-electric converter 20,
The signal is processed inside the node 1C, passes through the electro-optical converter 21, passes through the optical switch 23, and is output to the down transmission line 124. Optical switch 23
When the node 1C malfunctions, it continues to operate the link at the expense of the input and output of data for that node,
Operation signal 131 output in response to abnormal operation of node 1C
The optical switch 23 is switched by 132, and the node 1C is excluded. Except for the configuration and operation of the optical switching devices 22 and 23, the configuration and operation of the first embodiment of the node control system of the present invention are the same as those of the second basic configuration. Since an optical fiber is used as a transmission medium and an optical switch that can be operated from the outside is provided, even if the operation of a node becomes defective, the node can be excluded to form a link.

〔The invention's effect〕

As described above in detail, the node control method of the modified U-link method of the present invention can not only establish a link as the U-link method even if a failure occurs in the transmission medium and disconnect the transmission medium, By using an optical fiber, it is possible to increase the resistance to electromagnetic interference, and even when a node becomes defective, it can be excluded to establish a link, so a data link method with improved reliability is also provided. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is an explanatory view showing node transition control according to the present invention, and FIG.
FIG. 3 is a diagram showing transition conditions of the node of the present invention, FIG. 3 is a diagram showing transition status of the mode of the node of the present invention, and FIGS. 4A to 4C are explanations showing modes of the node of the present invention. FIG. 5 is a block diagram showing the configuration of the first embodiment of the node of the present invention, FIG. 6 is a block diagram showing the configuration of the second embodiment of the node of the present invention, and FIG. 7 is the present invention. 8 is a block diagram showing the configuration of a third embodiment of the node of FIG. 8, FIG. 8 is a block diagram showing an example of the configuration of a modified U-link using the node of the present invention, and FIG. 9 is a variant using the node of the present invention. FIG. 10 is a block diagram for explaining the operation of the U-link when it is abnormal, FIG. 10 is a block diagram showing an example of the configuration of the U-link using the conventional node, and FIG. 11 is the U-link using the conventional node. FIG. 6 is a block diagram for explaining the operation in the event of abnormalities. 1 ... node, 2 ... data terminal unit, 11, 13 ...
Clock detector, 12 ... Node detector, 14 ... Control logic, 15 ... Clock generator, 16 ... Mode inserter, 17
...... Data inserter.

Claims (1)

[Claims] 1. Upstream data is received from an upstream transmission medium on a preceding node side, output data of a data terminal is multiplexed, and then transmitted to an upstream transmission medium on a next stage node side, and downstream transmission is performed on a next stage node side. It accepts downlink data from the medium, sends it to the downlink transmission medium on the upstream node side, and receives it as input data to the data terminal in the repeater mode, and receives the upstream data from the upstream transmission medium on the upstream node side,
After the output data of the data terminal is multiplexed, it is sent to the upstream transmission medium of the next-stage node side and the downstream transmission medium of the previous-stage node side, and the loopback mode is taken in as the input data of the data terminal, and the clock at its own node. The output data of the data terminal is multiplexed and sent as upstream data to the upstream transmission medium of the next-stage node side, and the upstream data received from the upstream transmission medium of the previous-stage node side is directly used as downlink data for the upstream-stage node side. A node control method in which a node that transmits either to a downstream transmission medium, receives downlink data from a downstream transmission medium on the side of the next-stage node, and captures it as input data of a data terminal is connected to a node that can take either of them. In the above, the node determines from the uplink and downlink data received from the uplink and downlink transmission media, respectively. The presence or absence of a clock, the mode of the preceding node in the upstream data received from the upstream transmission medium, the ability to generate a clock signal including the signal representing the clock generation node number, and the upstream transmission. It is possible to send a signal indicating the mode of the local node in the data sent to the medium, detect the presence or absence of a clock on the transmission medium, detect the source of the clock, and check whether the preceding node is in the loopback mode. By the detection, (a) the repeater mode is used before the transition, and the clock mode is used after the transition when the upstream transmission line has no clock and the downstream transmission line has no clock. (B) Repeater mode before transition, clock at upstream transmission destination, loopback mode at direct downstream node, loopback mode after transition when downstream transmission line has no clock (c) Repeater mode before transition, uplink transmission If the line has a clock and the direct downstream node has a loopback mode, and the downstream transmission line has a clock, the transition mode is the clock mode. (D) Before the transition, the repeater mode, the upstream transmission line has a clock, and the direct downstream node has the repeater mode. Or, in clock mode, when there is no clock in the downlink transmission line, the transition mode is the loopback mode after the transition. (E) The repeater mode is before transition, the upstream transmission line has a clock, and the direct downstream node is in repeater mode or clock mode and the downstream transmission line. When there is a clock, the transition is in repeater mode. (F) Before transition, it is in loopback mode, and the upstream transmission line is clocked. None, if there is no clock on the downlink transmission line, the clock mode is after the transition. (G) When the transition mode is before transition, the upstream transmission line has a clock, the direct downstream node is the folding mode, and the downstream transmission line has no clock. After the transition is the loopback mode (h) Before the transition is the loopback mode, the upstream transmission line has a clock, the downstream node has the loopback mode, and the downstream transmission line has the clock, the transition is the clock mode (i) Transition The previous is loopback mode, there is a clock on the upstream transmission line, the direct downstream node is the repeater mode or the clock mode, and the loopback mode is after the transition when the downstream transmission line has no clock. (J) The loopback mode before the transition, the upstream transmission line If there is a clock in the node, the downstream node is in repeater mode or clock mode, and if the downstream transmission destination has a clock, the transition is repeated. (K) Clock mode before transition, no clock on upstream transmission line, clock mode after transition when there is no clock on downstream transmission line (l) Clock mode before transition, no clock on upstream transmission line , If the downstream transmission line has a clock, the clock mode is after the transition. (M) Before the transition is the clock mode, the clock of its own node is detected on the upstream transmission line, and after the transition, if the downstream transmission line has no clock. Folding mode (n) Clock mode before transition, clock of own node is detected on upstream transmission line, if downstream transmission line has clock, clock mode after transition (o) Clock mode before transition, If the clock of another node is detected on the upstream transmission line and the node immediately downstream is in loopback mode, and if there is no clock on the downstream transmission line, the clock mode is set after transition. (P) The clock mode is before transition, the clock of another node is detected on the upstream transmission line, the direct downstream node is in loopback mode, and the clock is after transition when there is a clock on the downstream transmission line (q) The clock mode is before transition, the clock of another node is detected on the upstream transmission line, the direct downstream node is repeat mode or clock mode, and if there is no clock on the downstream transmission line, the transition mode is the loopback mode. (R) Before transition In clock mode, the clock of another node is detected on the upstream transmission line, the downstream node is connected to the repeater mode or clock mode, and when the downstream transmission line has a clock, the node that becomes repeater mode after transition is connected. Node control method.