JPH0626338B2 - Modified U-link method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a U-link system, and is a highly reliable variant U.
Regarding the link method.

[Conventional technology]

Conventionally, a method of connecting a plurality of nodes and transmitting data in opposite directions to a transmission medium divided into an upstream and a downstream is shown in FIG. 8, in which data is input to the nodes L _{1 to} L _N and each node. and an output data terminal units E ₁ to E _N. A clock is generated at the 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), becomes a downstream transmission line, reaches the node L ₁ , and ends. At this time, each node supplies data from each data terminal unit to the upstream transmission line,
Data is supplied from the downlink transmission line to each data terminal unit.

Here, the situation when the transmission line connecting the nodes L ₂ and L ₃ is disconnected at the connection point X ₃ will be examined. As shown in FIG. 9, the connection point is simply disconnected, but if the self-recovery operation is not performed in the node, the upstream and downstream transmission lines are isolated and data transmission becomes impossible. The function stops. In practice, however, by short-circuiting the signals input and output to the node L ₂ In future transmission lines upstream and downstream links only node L ₁ · L ₂ is can exchange the established data. Meanwhile node L ₃ ~L clock is generated by _N in the node L _3, the node L ₃ ~L _N respective data terminal unit E through the transmission line upstream and downstream between the
₃ to E _N input and output enables link data between each other is established.

However, in this case, since the conventional link is divided and the link is established within each sublink, it is impossible to input / output data between the sublinks.

[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, it is an object of the present invention to provide a modified U-link system that solves the above drawbacks.

[Means for solving problems]

A modified U-link system of the present invention is to connect a plurality of nodes in a ring to a transmission medium divided into upstream and downstream, and to receive upstream data from an upstream transmission medium on the side of a preceding node,
After multiplexing the output data of the data terminal, it is sent to the upstream transmission medium of the next-stage node side, the downstream data is accepted from the downstream transmission medium of the next-stage node side, and it is sent to the downstream transmission medium of the previous-stage node side. At the same time, the repeater mode is taken as the input data of the data terminal, and the upstream data is received from the upstream transmission medium of the preceding node side.
After the data output from the data terminal is multiplexed, it is sent to the upstream transmission medium on the next node side and the downstream transmission medium on the previous node side, and the loopback mode is taken in as the input data of the data terminal. After the clock is generated and the output data of the data terminal is multiplexed, it is sent as upstream data to the upstream transmission medium on the next node side, and the upstream data received from the upstream transmission medium on the previous node side is directly used as downstream data on the upstream node side. In the clock mode in which the data is transmitted to the downstream transmission medium, the downstream data is received from the downstream transmission medium on the next node side, and the data is taken in as the input data of the data terminal. Figure 6 shows the presence / absence of a clock, the source of the clock, and the detection of whether the preceding node is in the loopback mode. The data input from the data terminal to the plurality of nodes connected in a loop that autonomously transits between the modes according to the transition conditions are multiplexed and then transmitted to the upstream transmission medium and received from the downstream transmission medium. Outputting data to a data terminal.

〔Example〕

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

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a block diagram for explaining the operation of the present invention in the event of an abnormality, and FIGS. 3 (a)-(c) are the nodes of the present invention. Explanatory diagram showing the mode,
FIG. 4 is an explanatory diagram showing transition control of nodes according to the present invention, and FIG.
FIG. 7 is a chart showing transition conditions of the node of the present invention, FIG. 6 is a chart showing mode transition status of the node of the present invention, and FIG. 7 is a block diagram showing a configuration of an embodiment of the node of the present invention. .

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

Referring to FIG. 1, one embodiment of the present invention shows that an upstream transmission medium, that is, an upstream transmission line 100, a downstream transmission medium, that is, a downstream transmission line 101, nodes N _{1 to NN,} and data corresponding to respective nodes. Data terminal unit E _1-
E _N, and the upstream transmission line 100 and the downstream transmission line 10
1 connects the nodes N _{1 to NN} , respectively. In such a case, the clock generator 102 of any one node, 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 output from each corresponding node to the upstream transmission line, and the data output from the downlink transmission line is output from each node to the corresponding data terminal unit. Next, referring to FIG. 2, the situation when the transmission line is disconnected will be described. For example, if the transmission line between the nodes N ₃ and N ₄ is disconnected at the connection point X ₁ , a clock is generated from the node N ₄ and the node N ₁ becomes a normal repeater and the node N ₃ outputs the upstream transmission line. The signal is directly connected to the downlink 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. Fig. 3
Commonly necessary actions for viewing (a) to (c) are supplying input data to an upstream transmission medium or an upstream transmission line and supplying output data from a downstream transmission medium or a transmission line. First mode shown in FIG. 3 (a) is (are connected to the node N _N-1 side to the node N _N shown in example FIG. 1) of the called repeater mode clock source side up transmission The data received on the medium, that is, the upstream transmission line (referred to as upstream data from the downstream node) is directly output to the upstream transmission line (sent to the upstream node), and the data received from the downstream transmission line (downstream data from the upstream node). Is directly applied to the clock source side (for example, the node N shown in FIG. 1).
Node N _N-1 is connected to the side) to the downstream transmission medium or the downlink transmission line and sends the (downstream node) are those with respect to _N. The second mode shown in FIG. 3 (b) is called the loopback mode, in which the upstream data from the downstream node is sent to the upstream node as it is, and is also sent to the downstream node as downlink data. Although downlink data is detected, it is not captured and is interrupted at this node. The third node shown in FIG. 3 (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 content of detection of the ring situation 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 is a clock on both 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. 5 shows the transition conditions of these nodes in more detail, and FIG. 4 shows the contents of the transition control of the nodes under these conditions. Symbol 1A in FIGS. 4 and 5
The symbol 1B ... indicates the control condition. Further, FIG. 6 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. 1, 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 not detected in the downstream transmission line even if the clock is detected in the upstream clock transmission line at the nodes N ₂ and N ₃ . The clock in the node N ₄ to N transmission lines upstream and downstream the _N is not detected.
Further, at the node N ₁ , the clock input from the upstream transmission line is not detected. At this time, the node N ₂
Although N ₃ is in the loopback mode depending on the transition condition of 1C in FIG. 5, since the operating time of the node is generally different, the node that transits earlier becomes dominant over the node that is delayed.

In this case, when the node N ₃ enters the loopback mode, the node N ₂
Since clocks are detected on the up and down transmission lines, the signal remains in the repeater mode under the transition condition of 1F in FIG. However, when the node N ₂ is in the loopback mode, the node N ₃ has a clock in the upstream transmission line but has no clock in the downlink transmission line, and the direct downstream node N ₂ is in the loopback mode. Under the transition condition of 1B, the node N ₃ is in the return 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.

In contrast node N ₄ to N _N, since there is no clock to the transmission line upstream and downstream, earliest node of the transition operation by transition condition of FIG. 5 of 1A is a clock mode.
At this time, the nodes downstream of the node in the clock mode, for example, the node N _N , have the clocks of the upstream and downstream transmission lines, and therefore remain in the repeater mode. 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 enters the clock mode. Therefore, the clock mode node sandwiched between the repeater mode nodes has clocks on the upstream and downstream transmission lines,
Note that the immediate downstream node is a repeater, and other nodes are still detected, so the fifth node including the node N ₁ is detected.
All are in the repeater mode depending on the transition condition of 3F in the figure.

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.

Referring to FIG. 1, according to the present invention, the nodes N _{1 to NN} are upstream transmission media, that is, transmission lines 1 configured by lines such as coaxial cables.
00 and the downstream transmission medium, that is, the downstream transmission line 101, to connect the data terminal units D _{1 to DN} to the nodes N _{1 to NN.}
The respective data are supplied to the upstream transmission line 100 through the through, and the data from the downstream transmission line 101 are sent to the terminal unit D ₁
Through D _N to the corresponding nodes N ₁ through N _N , respectively. Each node is configured so that the mode transitions shown in FIG. 6 can be made in the link, and one embodiment thereof is shown in FIG.

Next, the configuration and operation of the node will be described.

The signal of the upstream transmission medium is input from the upstream transmission line 111 to the node 1 and output to the upstream transmission line 112, the signal of the downstream transmission medium is input from the downstream transmission line 113 and output to the downstream transmission line 114, and the transmission line is coaxial. Composed of cable or two-wire system. Further, data is output from the data terminal unit 2 to the upstream transmission line 112 through the data inserter 17, and the data output from the downstream transmission line 113 is also supplied to the data terminal unit 2.

Next, the node 1 includes the clock detectors 11 and 13, the node detector 12, the control logic 14, and the clock generator 15.
1, a mode inserter 16, a data inserter 17, and changeover switches SW1A, SW1B, and SW2.

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 receives the clock generation node from the upstream transmission line 111. (That is, the clock source node) and the detection of whether the immediately downstream node (node at the preceding stage) is in the loopback mode or another mode, and the result is detected by the control logic 14.
Enter into.

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 the changeover switch SW1A ・ S
Activate W1B and SW2 (set to ON state)
In particular, when the changeover switch is not activated, the repeat mode is set. Next, changeover switch SW1A
And when SW1B operates (turns on),
A clock output from the clock generator 15 and an indicator signal indicating that its own node is the clock source are the changeover switch SW1.
It is output to the upstream transmission line 112 through A, and the upstream transmission line 1
The input of 11 is output to the downlink transmission line 114 through the changeover switch SW1B, and the mode of the own node becomes the clock mode. Further, when the changeover switch SW2 is activated and is in the ON state, the output of the upstream transmission line 112 is simultaneously output to the downstream transmission line 114 through the changeover switch SW2, the mode of the own node becomes the return mode, and the own node is the return mode. Is also output through the mode inserter 16 into the frame of the transmission data on the upstream transmission line 112. 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. 6 and the incidental conditions.

〔The invention's effect〕

As described in detail above, the modified U-link system of the present invention establishes a link as the U-link system even if a failure occurs in the transmission medium and disconnects it. There is an effect that a highly reliable data link system can be provided by operating without degrading the function.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a block diagram for explaining the operation of the present invention in the event of an abnormality, and FIGS. 3 (a)-(c) are the nodes of the present invention. Explanatory diagram showing the mode,
FIG. 4 is an explanatory diagram showing transition control of nodes according to the present invention, and FIG.
FIG. 6 is a chart showing transition conditions of the node of the present invention, FIG. 6 is a chart showing mode transition status of the node of the present invention, FIG. 7 is a block diagram showing the configuration of one embodiment of the node of the present invention, FIG. 8 is a block diagram showing an example of the configuration of a conventional technique, FIG.
The figure is a block diagram for explaining the operation of the prior art in the event of an abnormality. N _{1 to NN} ... Nodes, D _{1 to DN} ... Data terminal unit, 100 ... Upstream transmission line, 101 ... Downstream transmission line, 1
02 ... Clock generator.

Claims (1)

[Claims] 1. A plurality of nodes are connected in a ring and transmitted to a transmission medium divided into upstream and downstream, and upstream data is received from an upstream transmission medium on the side of a preceding node.
After multiplexing the output data of the data terminal, it is sent to the upstream transmission medium of the next-stage node side, the downstream data is accepted from the downstream transmission medium of the next-stage node side, and it is sent to the downstream transmission medium of the previous-stage node side. At the same time, it accepts the upstream mode from the upstream transmission medium on the front node side as well as the PETER mode that captures it as the input data of the data terminal.
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. The node that can take either of the following two modes: the clock mode on the transmission medium that sends out to the downstream transmission medium, receives the downstream data from the downstream transmission medium on the next node side, and captures it as the input data of the data terminal. Is detected, the clock source is detected, and the previous node is in the folding mode. Peter mode, the clock without the upstream transmission line, after the case of no clock transition becomes a clock mode to the downlink transmission line. (2) The repeater mode is before transition, the upstream transmission line has a clock, the direct downstream node is loopback mode, and the downstream transmission line is without clock, the loopback mode is after transition. (3) When the repeater mode is before transition, the upstream transmission line has a clock, the direct downstream node is loopback mode, and the downstream transmission line has a clock, the transition mode is clock mode. (4) The repeater mode is used before the transition, the upstream transmission line has a clock, the direct downstream node is the repeater mode or the clock mode, and the downstream transmission line has no clock when the transition mode is the return mode. (5) The repeater mode is used before the transition, the upstream transmission line has a clock, the direct downstream node has the repeater mode or the clock mode, and the downstream transmission line has the clock after the transition is the repeater mode. (6) When there is no clock in the upstream transmission line and no clock in the downstream transmission line before the transition, the clock mode is used after the transition. (7) The loopback mode is before transition, the upstream transmission line has a clock, the downstream node is loopback mode, and the downstream transmission line has no clock, the loopback mode is after transition. (8) The loop mode is set before the transition, the upstream transmission line has the clock, the direct downstream node is the loop mode, and the downstream transmission line has the clock, the transition mode is the clock mode. (9) The loopback mode is before transition, the upstream transmission line has a clock, the downstream node is repeater mode or clock mode, and the network after the transition is loopback mode when there is no clock. (10) The loop mode is set before the transition, the upstream transmission line has a clock, the direct downstream node is the repeater mode or the clock mode, and the clock is set on the downstream transmission line, the transition mode is the repeater mode. (11) Clock mode before the transition, no clock on the upstream transmission line, and no clock on the downstream transmission line, the clock mode after the transition. (12) When there is no clock in the upstream transmission line and there is a clock in the downstream transmission line before the transition, the clock mode is after the transition. (13) Before the transition, the clock mode is set, and when the clock of the own node is detected on the upstream transmission line and the downstream transmission line has no clock, the loop mode is set after the transition. (14) The clock mode is before the transition, and the clock of its own node is detected on the upstream transmission line. If the downstream transmission line has a clock, the clock mode is after the transition. (15) The clock mode is before the transition, the clock of the other node is detected on the upstream transmission line, the direct downstream node is the folding mode, and the clock mode is after the transition when the downstream transmission line has no clock. (16) The clock mode is before transition, the clock of another node is detected in the upstream transmission line, the direct downstream node is in loopback mode, and the clock after transition is clock mode when there is a clock in the downstream transmission line. (17) The clock mode is before the transition, the clock of another node is detected on the upstream transmission line, the direct downstream node is the repeater mode or the clock mode, and the loop mode is after the transition when the downstream transmission line has no clock. (18) The clock mode is before transition, the clock of another node is detected on the upstream transmission line, the direct downstream node is the repeater mode or the clock mode, and if the downstream transmission line has a clock, the repeater mode is after transition. In accordance with the transition conditions shown in, the data input from the data terminal to the plurality of nodes connected in a loop that autonomously transits between the modes is sent to the upstream transmission medium and then transmitted from the downstream transmission medium. A modified U-link system that outputs received data to a data terminal.