JPS6248147A - Method and equipment for communication of highest priority in loop network - Google Patents

Abstract

PURPOSE:To prevent the decrease in the transmission efficiency of the instantaneous system communication by sending a signal shorter than the signal sent to acquire the transmission right when no significant signal to be sent in its own node station exists at the period while a trigger station sends the 2nd trigger signal. CONSTITUTION:When an address detection section 17 detects the address state of a transmission line 6 just after a packet signal sent from an upperstream node station passes and acquires the access right to the transmission line 6, the section 17 reads a data to be sent from a transmission data memory 12 and sends a packet signal S1. A control signal detection section 18 detects the 2nd trigger signal TG2, a head address storing a data in the transmission data memory 12 is stored in an address counter 117 when the level of an output 18-2 goes to logic 1 and the value of a register 115 is stored in a data length counter 118 because the value of the register 114 is logic 0 and after the access right to the transmission line 6 is acquired, the address detection section 17 sends a dummy packet signal D1. Thus, the communication of the instantaneous system is accommodated efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to priority control of loop networks, particularly priority control for real-time communications.

[Prior art]

As a loop network that integrates real-time communication such as voice and video, and time-based communication such as data and still images, it was described in 1982, Institute of Electronics and Communication Engineers Exchange Study Group 5E83-107, ``A Study of High-Speed Synchronous Packet Loops.'' There is something like that. This loop network and priority control for providing real-time communication services will be explained.

FIG. 6 is a diagram showing the configuration of a loop network, which is composed of a trigger station 5, node stations 1, 2, 3.4, and connected by a loop-shaped transmission line 6. Trigger station 5
is a trigger signal T with a constant period T as shown in FIG. 7(a).
G is sent to poll the communication with the highest priority, that is, the immediate communication. In FIG. 6(a), node stations 1 and 3 have already acquired the highest priority transmission right,
These node stations send out packet signals 31, S3. In this network, a node station that wants to newly perform communication with the highest priority first performs transmission with the second priority so as not to interfere with the transmission of a node station that is already communicating with the highest priority.

This second-rank communication is a polling signal P○ sent by the trigger station after all the highest-priority communications have finished.
Polled by L. In FIG. 7(a), the node station 2.4 transmits each packet signal 32' with the second priority in order to newly acquire the transmission right with the highest priority.
, S4' are transmitted. After the second-order communication is completed, the trigger station 5 further transmits a polling signal P○L to perform a low-priority communication (^-ring).

Based on the fact that the node station 2.4 was able to transmit with the second priority, from the next cycle onwards, it will transmit as shown in Fig. 7(b).
The packet signals S2 and 34 are transmitted with the highest priority as shown in FIG. That is, based on the trigger signal TG, the node stations 1, 2.3.4 send packet signals Sl, S2.
S3. S4 respectively. In this case, node station 2 is polled before node station 3, but the packet signal 31. S2. S3. Since the sum of the time widths of S4 is guaranteed to be shorter than the cycle T in the previous cycle, the node station that is already communicating with the highest priority, in this case node station 1.3
will not be unable to send.

[Problems with conventional technology]

As explained above, such a loop network is characterized in that each node station can autonomously control the width performance. On the other hand, such communication services with the highest priority are efficient for communications such as voice, where significant data is constantly generated during the time a call is set up, but when instantaneousness is desired, significant data is generated. For communications that occur only intermittently, the time during which data is transferred is considerably smaller than the time during which the highest priority transmission right is held, resulting in a reduction in transmission efficiency.

[Purpose of the invention]

An object of the present invention is to provide a highest priority communication method and device that does not reduce the transmission efficiency of real-time communication.

[Structure of the invention]

In the communication method in a loop network of the present invention, a trigger station and a plurality of node stations are connected in a loop, and the trigger station sends out a trigger signal at a constant cycle to poll communication with the highest priority. In a loop network that transmits a polling signal and polls communications in order of priority, first and second trigger signals are provided as the trigger signal, and the trigger station sends out the first trigger signal. Only in this period, a node station that wants to newly transmit with the highest priority attempts transmission to acquire the right to transmit, and if the transmission is successful, acquires the right to transmit with the highest priority, and then - If a node that has acquired a high priority transmission right does not have a significant signal to transmit within its own node station in the cycle in which the trigger station transmits the second trigger signal, the node station that has acquired a high priority transmission right will continue to acquire the transmission right. It is characterized by transmitting a shorter signal than the signal transmitted to.

In the communication device in the loop network of the present invention, a trigger station and a plurality of nodes are connected in a loop, and the trigger station polls the highest priority communication by sending out a trigger signal at a constant cycle, In a network that transmits a polling signal within the cycle and polls communications in descending order of priority, the trigger station includes means for transmitting first and second trigger signals as the trigger signal, The node station includes a first detection section that detects a first trigger signal, a second detection section that detects a second trigger signal, a transmission buffer section that stores a signal to be transmitted, and the transmission buffer. a first control information storage section that stores control information for transmitting internal signals; and a second control information storage section that stores whether or not a significant signal to be transmitted is stored in the transmission buffer section. and a third control information storage unit that stores control information for a signal to be transmitted when there is no significant signal to be transmitted; A node station that is equipped with a transmission control unit that transmits on the transmission path and that has already acquired the highest priority transmission right does not control the transmission control unit in the period in which the first detection unit detects the first trigger signal. The signal in the transmission buffer section is transmitted based on the contents of the first control information storage section, and the signal in the second control information storage section is transmitted.
In the cycle in which the detection unit detects the second trigger signal,
If it is stored in the second control information storage section that there is a significant signal to be transmitted, the signal is transmitted based on the contents of the first control information storage section, and the second control information storage section If it is stored in the information storage section that there is no significant signal to be transmitted, the signal is transmitted based on the contents of the third control information storage section.

〔Example〕

An embodiment of the invention is shown in FIG. FIG. 1(a) shows the trigger station 5, and the first ffl(b) shows one of the node stations 1, 2, 3.4.

As shown in the figure, the trigger station 5 includes a delay circuit 54 and a switch 53 connected in series to a loop-shaped transmission line 6.
, and further a control signal transmitter 51. Timer 52. Receiving section 55
．． Transmission buffer 56. It is composed of an idle detection section 57.

On the other hand, each of the seven transistors 1, 2, 3.4 has a delay circuit 14 connected in series to the transmission line 6 as shown in the figure. switch 13 and further transmission control section 11. Transmission data memory 12
．． Receiving section 15. Transmission buffer 16. Idle detection section 17
．． It is composed of a control signal detection section 18.

When the control signal transmitter 51 in the trigger station 5 receives the start notification of the cycle T from the timer 52, it connects the switch 53 to the transmission buffer 56 side and transmits the signal in the transmission buffer 56. The frame structure of this signal is shown in FIG. This signal frame has a start delimiter sD and an end delimiter ED.
The bits tl, t2 . . . are separated by bits tl, t2 . pj? It consists of a header section (including address information, etc.) IDR and an information field INF○. Pit I-tl=1 is N of period T
(N is an integer of 2 or more) indicates the first trigger signal TGI sent out at the first period of the multi-period NXT, and bit t2=1 indicates the second trigger signal TGI sent out at the start of the other periods T.
The bit pβ=1 indicates the trigger signal TG2 for each period T
This shows the polling signal POL sent within. Note that the packet signal sent from each node station is B=
t2=pβ=O, and is distinguished from the trigger signal and polling signal.

When the control signal transmitter 51 receives the start notification of the period T from the timer 52, if it indicates the start of the multi-period NXT, the control signal transmitter 51 sets its output 51-1 to 1 and outputs the first signal with tl=1. The trigger signal TGI is stored in the transmission buffer 56 and sent to the transmission line 6 via the switch 53. When receiving a notification of the start of any other period T, the output 51-2 is set to 1 and the second trigger signal TG2 with t2=1 is stored in the transmission buffer 56 and sent out.

Furthermore, after transmitting the trigger signal TG1 or TG2, the trigger station 5 detects that the transmission path 6 is in an idle state immediately after the idle detection section 57 passes the packet signal transmitted by the upstream 7-station. Gained access to 6? Each time, the output 51-3 is set to 1 and a polling signal POL of pA=1 is sent out.

Note that the delay circuit 54 has a function of delaying the signal on the transmission line 6 by the time required to control acquisition of the access right to the transmission line 6 described above, and the receiving unit 55 receives the packet signal addressed to the trigger station 5. Detect and receive this.

The above is a description of the transmission operation of the trigger station 5, and next, the transmission operation of the node station will be explained.

When the control signal detecting section 18 in the /- torsion shown in FIG.
When the polling signal POL is detected, the output 18-2 is set to 1, and when the polling signal POL is detected, the output 18-3 is set to 1 and the transmission control unit 11 is notified.

Therefore, the transmission control unit 11 outputs the output 18-1 or the output 1
When 8-2 is 1, it is determined that the highest priority packet signal should be transmitted on the transmission path 6, and the second
It is possible to identify priorities below the Also, output 1
When output 8-1 is 1, it can be determined that the multi-period NXT has started, and when output 18-2 is 1, it can be determined that another period has started. After the transmission control unit 11 identifies the priority to be transmitted as described above, when the idle detection unit 17 detects the idle state of the transmission path 6 immediately after the packet signal transmitted by the upstream node station has passed. It acquires the access right to the transmission path 6, reads out the data to be transmitted from the transmission data memo +J12, stores it in the transmission buffer 16, and transmits it via the switch 13.

Note that the delay circuit 14 has a function of delaying the signal on the transmission line 6 by the time required to control acquisition of the access right to the transmission line 6 described above, and the receiving unit 15 receives the packet signal addressed to its own mate station. Detect and receive this.

FIG. 3 is a diagram showing the flow of signals transmitted by the trigger station 5 and each node station, and FIG. 3(a)
shows the acquisition of the highest priority transmission right, (b) and (c
) is a diagram showing the flow of signals transmitted by each node station after the high priority transmission right is granted Mf8.

In FIG. 3(a), the trigger station 5 transmits the first trigger signal TGI in period 1 and multi-period Nx
Notifies the start of T (in the figure, N indicates 3). At this time, the node station 3 has already acquired the highest priority transmission right and transmits the packet signal S3 immediately after passing the TGI. Next, the trigger station 5 sends a polling signal POL to poll the second priority communication. At this time, a communication request with the highest priority has occurred in node stations 1 and 4, and packet signals Sl' and S4 are attempted to be transmitted to acquire the transmission right.
° is sent. Transmission of all of these packets is completed normally, node stations 1 and 4 acquire the highest priority transmission right, and can perform transmission with the highest priority from the next cycle 2 onwards.

When the trigger station 5 transmits the second trigger signal TG2 and starts a new cycle 2, the node station 1
transmits the highest priority packet signal S1 after passing through TG2. On the other hand, node station 4 has not started transmitting within this period 2, but since transmission attempts to acquire the transmission right are limited to the period starting with the TGI, node station 4 has not started transmitting. As shown in the figure, in period 3, the packet signal S4 remains in the acquired state.
Send. Furthermore, the node station that has acquired the high-priority transmission right receives a packet when the next TGI is transmitted and a new multi-period NXT starts (period 4 is the start of a new multi-period in the figure). By transmitting signals, the right to transmit can be continuously acquired.

Note that the node station that was unable to calculate the transmission right iMt at the second highest 1 light reception intensity in cycle 1 is prohibited from making the above attempt again in the remaining cycles of this multi-cycle, that is, cycles 2 and 3. .

FIG. 3(b) i'C) is a diagram explaining the transmission operation of the node station once it has acquired the transmission right. The explanation will be given with reference to the detailed configuration of No. 11.

As shown in FIG. 3(b), the node stations 1.3 and 4, which have already acquired the transmission right, send the packet signal 3 in period 1, which is the start of the multi-period starting with TGI.
1. Transmit S3 and S4. Therefore, each of these node stations remains in a state in which it has acquired the right to transmit until the next TG1 is transmitted. However, as explained above, in communications where immediacy is desired but meaningful data only occurs intermittently, the packet signal necessary to acquire the transmission right is always needed. If the transmission path continues to be transmitted, invalid packets will be included on the transmission path, resulting in a decrease in transmission efficiency.

In period 2 shown in FIG. 3(b), the node station 1 has no significant data to transmit, and transmits a dummy packet signal D1 shorter than the packet signal S1 necessary for acquiring the transmission right. Furthermore, in the next cycle 3, there is no significant data to be transmitted to any of the node stations 1, 3 and 4, and dummy packet signals Di, D3 . Send D4.

FIG. 4 is a diagram showing the part that mainly controls communication with the highest priority in the transmission control unit 11 of each node station that is to perform the transmission as described above.
11, registers 112, 11.3, 114, 115, selector 116, address counter 117, data length counter 118, and 119 and 120.

When the terminal handling unit 111 receives data to be transmitted from a terminal housed in its own node station, it stores the data in the transmission data memory 12, writes the start address where the data is stored in the register 112, and stores the data in the register 112. The signal length of this data is written in 113, and 1 is written in register 114 to indicate that significant data to be transmitted has already been written. Note that the signal length of a dummy packet signal to be transmitted when there is no significant data to be transmitted is written in the register 115 in advance. For example, if the field length of the INFO field of the dummy packet signal is O, the field length of the header portion HDR is written in the register 115. When the output of the OR gate 120 is 1, the selector 116 outputs the value of the register 113 and outputs the value of the OR gate [20
If the output is 0, the value of register 115 is output.

When the output of the OR gate 119 is 1, the address counter 117 and the data length counter 118 each have a register 1.
12, the output value of the selector 116 is stored.

Therefore, in the example shown in FIG. 3(b), in the node station 1, the control signal detection section 18 detects the first trigger signal TGI in cycle 1, and when the output 18-1 becomes 1, the address counter 117 stores the transmission data memory 12. , and the value of the register 113 is stored in the data length counter 118 regardless of the value of the register 114, that is, regardless of whether there is significant data, and the address is detected. When the unit 17 detects the address state of the transmission line 6 immediately after the packet signal transmitted by the upstream node station passes through and acquires the right to access the transmission line 6, the data The data to be transmitted is read from the transmission data memory 12 until the value of the long counter 118 becomes 0, and the packet signal S1 is transmitted. In the next cycle 2, the transmission control unit 11 writes O to the register 114 because there is no data to be transmitted. The control signal detection section 18
When the trigger signal TG2 is detected and the output 18-2 becomes 1, the address counter 117 similarly stores the start address where the data in the transmission data memory 12 is stored, and the data length counter 118 stores the value of the register 114. Since it is 0, that is, there is no significant data, the value of the register 115 is stored, and after the address detection unit 17 acquires the right to access the transmission line 6 as described above, it transmits the dummy packet signal D1.

Furthermore, in FIG. 3(C), the node station 3 accommodates three terminals, and the packet signal S3 transmitted by the node station 3 is the terminal operator's packet signal p1, the terminal 2
packet signal p2 of terminal 3 and packet signal p3 of terminal 3, and in cycle 3, if there is no significant data to be transmitted to terminal 2, only terminal 2 transmits a dummy packet signal D2. It is shown that.

FIG. 5 is a diagram showing the detailed configuration of the transmission control section 11 when accommodating a plurality of terminals in this manner.

The transmission control unit includes a terminal support unit 211 and a control memo 'J 21.
2.213°214, register 215, selector 216
, address counter 217, 222, holding circuit 223,
It consists of a data length counter 218 and an OR gate 224.120. Compared to the configuration of the transmission control unit 11 in FIG. 4, the register 112 that stores the start address is stored in the control memory 212, and the register 113 that stores the data length is stored in the control memory 213. The main difference is that the control memory 214 replaces the register 114 that stores the .

The terminal support unit 211 stores the data to be transmitted from the accommodated terminal in the transmission data memory 12, writes the start address where the data is stored in the control memory 212, writes the signal length of this data in the control memory 213, Furthermore, 1 is written to indicate that significant data to be transmitted to control memory 214 has already been written. When storing a plurality of pieces of transmission data, the control information for each piece of transmission data is sequentially written. Note that the signal length of a dummy packet signal to be transmitted when there is no significant data to be transmitted is approximately written in the register 215.

This is the same as the previous example. Selector 216 outputs the value of control memory 213 when the output of OR gate 120 is 1, and outputs the value of register 215 when the output of OR gate 120 is 0. The holding circuit 223 holds the TGI detection output 18-1 of the control signal detection unit 18 for a period T. In addition, within the period starting with eTG l, OR
The output of the gate 120 becomes 1, and the output of the selector 216 becomes the value of the control memory 213. Also address counter 2
22 is the detection output 18-1 of TGI and TG2. IL-
2 via the OR gate 224, and its contents are incremented each time one packet signal is transmitted. Therefore, the control memory 212.213.21
The data in 4 is sequentially read out from the start address every cycle by the output of the address counter 222, and the output values of the control memory 212 and selector 216 are stored in the address counter 217 and data length counter 218, respectively, for one packet signal. Stored each time transmission is completed.

〔Effect of the invention〕

As explained above, according to the present invention, when data to be transmitted is generated, it can be transmitted immediately for communication where immediacy is desired but the data to be transmitted is generated only intermittently. If there is no meaningful data to be transmitted, it is possible to retain only the transmission right and allocate the transmission capacity to waiting communication with simple control.
Immediate communication can be efficiently accommodated, and the effect obtained is significant.

[Brief explanation of drawings]

1 is a diagram showing the configuration of a trigger station and a node station, FIG. 2 is a diagram showing a frame structure of a packet signal, FIGS. 3 and 7 are diagrams showing a signal flow, and FIGS. 5
The figure shows the internal configuration of the transmission control unit in the node station, and FIG. 6 shows the configuration of the loop network. 1, 2.3.4 ・・・・・・・・・ Node station 5 ・・・・・・・・・・・・・・・ Trigger station 6 ・・・・・・・・・・・・・・・
・・・ Transmission line 11 ・・・・・・・・・・・・・・・
... Transmission control section 11-1.111-2 ...
... Output 12 of the transmission control section ......
...... Transmission data memory 13, 53
・・・・・・・・・・・・ Switch 14, 54
...... Delay circuit 15, 55 ・
...... Receiving section 16, 56...
...... Transmission buffer 17, 57...
・・・・・・・・・ Idle detection section 18 ・・・
・・・・・・・・・・・・・・・ Control signal detection section 18
-1.18-2.18-3... Output 51 of control signal detection section ...... Control signal transmission section 51-L 51-2.51 -3... Output 52 of control signal transmitting section......
...... Timer 111, 211...
...Terminal support section 112, 113.114.115
．． 215... Register 116, 216...
・・・・・・ Selector 17, 217.222 ・・
...Address counter 118.218...
...... Data length counter 212, 213.2
14... City I11 wholesale memory 119, 120
．． 224・・・OR Gate agent Patent attorney
Yoshiyuki Iwasa (a) Figure 1 Figure 4 Figure 5 Figure 6 (a) (b) Figure 7

Claims (3)

[Claims] (1) A trigger station and a plurality of node stations are connected in a loop, and the trigger station polls the communication with the highest priority by sending out a trigger signal at a certain period, and if the communication is within the period, the polling signal is sent out. In a loop network that transmits a communication and polls the communication in order of priority, first and second trigger signals are provided as the trigger signal, and only in the period in which the trigger station sends out the first trigger signal, a new A node station that wants to transmit with the highest priority performs a transmission attempt to acquire the right to transmit, and if the transmission is successful, it acquires the right to transmit with the highest priority, and once it has acquired the right to transmit with the highest priority. If the node station does not have a significant signal to be transmitted within its own node station in the period in which the trigger station transmits the second trigger signal, the node station transmits a shorter signal than the signal transmitted for acquiring the transmission right. A communication method of highest priority in a loop network characterized by: (2) The trigger station transmits the first trigger signal only at a cycle that is an integer multiple of 2 or more of the cycle. Communication method. (3) A trigger station and a plurality of node stations are connected in a loop, and the trigger station is
In a network in which a trigger signal is sent out at a constant cycle to poll the communication with the highest priority, and within the cycle, a polling signal is sent out to poll the communication in order from the highest priority. The node station includes means for transmitting first and second trigger signals as trigger signals, and the node station includes a first detector for detecting the first trigger signal and a second detector for detecting the second trigger signal. a detection unit, a transmission buffer unit that stores a signal to be transmitted, and a first control information storage unit that stores control information for transmitting the signal in the transmission buffer unit;
a second control information storage unit that stores whether or not a significant signal to be transmitted is stored in the transmission buffer unit; and a second control information storage unit that stores control information for a signal to be transmitted when there is no significant signal to be transmitted. 3 control information storage section, and a transmission control section that transmits a signal onto the transmission path based on the contents of the first, second, and third control information storage sections, and has already acquired the highest priority transmission right. In the node station, the transmission control unit transmits the signal in the transmission buffer unit based on the contents of the first control information storage unit in the cycle in which the first detection unit detects the first trigger signal. , if it is stored that there is a significant signal to be transmitted to the second control information storage unit in the cycle in which the second detection unit detects the second trigger signal, the first transmits a signal based on the contents of the control information storage unit, and if it is stored that there is no significant signal to be transmitted to the second control information storage unit, the third control information storage unit A communication device with the highest priority in a loop network, which transmits a signal based on the content of.