JPS6248148A - Communication system with highest priority in loop network - Google Patents

Abstract

PURPOSE:To prevent the reduction in the transmission efficiency of a instantaneous system communication by sending a data when a significant signal to be sent exists at the period while a trigger station ends the 2nd trigger signal and not sending the data when not in existence. CONSTITUTION:When a node station 1 acquires always the transmission right with the highest priority at the start point of time of a multi-period and node stations 3, 4 desire the transmission with the highest priority, the trigger station 5 sends a trigger signal TG1 representing the start of the 1st period of the multi-period and polling the communication with the highest priority, then only the node station 1 acquiring already the right of transmission sends a packet signal S1. When the significant data to be sent exists, it is processed into a packet and the result is sent as the packet signal S1, and even when no significant data to be sent exists, a packet signal is sent to the transmission line 6 to ensure the transmission right with the highest priority. 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 standby communication such as data and still images, the one described in 1981 IEICE Exchange Study Group 5E81107 "A Study of High-Speed Synchronous Packet Loop" There is. This loop network and priority control for providing real-time communication services will be explained.

FIG. 4 is a diagram showing the configuration of a loop network, which is composed of a trigger station 5 and a node station 1.2.3.4, which are 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. 5(a).
G is sent to poll the communication with the highest priority, that is, the immediate communication. In FIG. 5(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 perform a new highest-priority communication first transmits at the second-highest intensity, 1, so as not to interfere with the transmission of a node station that is already performing a highest-priority communication. . This second-rank communication is polled by the polling signal POL transmitted by the trigger station 9 after all the highest-priority communications have been completed. FIG. 5(a) shows a state in which the node station 2.4 transmits each of the packet signals S2' and S4' with the second priority in order to newly acquire the transmission right with the highest priority. It shows.

After the second-rank communication is completed, the trigger station 5 further transmits a polling signal POL to further poll low-priority communication.

Based on the fact that node stations 2 and 4 were able to transmit with the second priority, from the next cycle onwards, the
The packet signals S2” and S4° with the highest priority as shown in
A packet signal with the same packet length as S2. Transmission of S4 is performed. That is, based on the trigger signal TG, the node stations 1, 2.3.4 transmit the packet signal s1. S2. S3.
S4 respectively. In this case, node station 2 is polled before node station 3, but the packet signals Sl, S2 . S3. Since the sum of the time widths of S4 is guaranteed to be shorter than the cycle T in the previous cycle, it is unlikely that the node stations that are already communicating with the highest priority, in this case node stations 1 and 3, will be unable to transmit. do not have.

[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 that does not reduce the transmission efficiency of real-time communication.

[Structure of the invention]

In the highest priority communication method in the loop network of the present invention, a trigger station and a plurality of node stations are connected in a loop, and the trigger station transmits a trigger signal at a constant cycle to perform the highest priority communication. In a loop network that performs polling, transmits a polling signal within the cycle, and polls in order from communication with a high priority, the first trigger signal is used as the trigger signal.
and a second trigger signal is provided, and only in the period in which the trigger station sends out the first trigger signal, a node station that newly desires to transmit with the highest priority attempts transmission to acquire the transmission right, If the transmission is successful, the node station acquires the highest priority transmission right, and once the highest priority transmission right is acquired, the node station transmits a significant signal to be transmitted in the cycle in which the trigger station transmits the first trigger signal. If there is a significant signal, the signal is transmitted, and if there is no significant signal, a 5G effective signal is transmitted for maintaining the transmission right, and is transmitted in the period in which the trigger station transmits the second trigger signal. It is characterized in that if there is a significant signal to be transmitted, the signal is transmitted, and if there is no significant signal to be transmitted, it is not transmitted.

〔Example〕

An embodiment of the invention is shown in FIG. FIG. 1(a) shows a trigger station 5, and FIG. 1(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 the loop-shaped transmission line 6.
．． Furthermore, the 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 node station 1, 2, 3, 4 has a delay circuit 1 connected in series to a loop-shaped transmission line 6 as shown in the figure.
4. switch 13, 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 period 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, an end delimiter E
D and are separated by bits tl, t2 . pj2, a header section HDR containing address information, and an information field INFO. Beep) tl=1 is N times the period T (
t3
=1 indicates the second trigger signal TG2 sent out at the start of other periods T, and bit pβ=1 indicates the polling signal POL sent out within each period T. Note that the packet signal sent from each node station is t 1 =
It is set as t2=p1=0 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 TG1 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 the trigger station 5 sends out the trigger signal TGI or TG2,
When the idle detection unit 57 detects that the transmission path 6 is in an idle state immediately after the passage of a packet signal transmitted by an upstream node station, it grants access to the transmission path 6.
Ik 7G, and each time the output 51-3 is set to 1, a polling signal P○L with bit pβ=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 described.

The control signal detection unit 18 in the node station shown in FIG. 1(b) sets its output 18-1 to 1 when it detects the first trigger signal TGI described above, and sets its output 18-1 to 1 when it detects the second trigger signal TG2. 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 section 11
When the output 18-1 or the output 18-2 is 1, it is identified that the highest priority packet signal should be transmitted on the transmission line 6, and the number of times the output 18-3 becomes 1 is counted. By doing this, it is possible to identify the second and lower priorities. Furthermore, when the output 18-1 is 1, it can be determined that the multi-cycle NXT has started, and when the output 18-2 is 1, it can be determined that another cycle 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 access rights to the transmission path 6, reads data to be transmitted from the transmission data memory 12, 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 re-control the access right to the transmission line 6 as described above, and the receiving unit 15 receives a packet addressed to its own node station. Detect and receive signals.

The operation of the transmission control section 11 will be explained in more detail. First, control for obtaining the highest priority will be explained. 1st
In the cycle started by the trigger signal TGI, that is, in the cycle started by the output 18-1 of the control signal detection unit 18, a packet signal of the same length as the packet signal to be transmitted with the highest priority is sent to the control output 11- 2, the data is stored in the transmission data memory 12, and when the bird detects passage of the first polling signal from the station through the output 18-3, it recognizes that polling with the second priority is being performed, and stores the transmission data in the transmission data memory 12. The packet signal in 2 is transferred to the transmission buffer 16, and after acquiring the access right, the control output 11
-1 switches the switch 13 to the transmission buffer 16 side and performs transmission. If the transmission is successful, transmission with the highest priority is permitted from the next cycle onwards.

If the access right cannot be acquired within this period, transmission with the highest priority is not permitted and such transmission control is prohibited until the next first trigger signal TGI is detected.

When the highest priority is obtained, if there is significant data to be transmitted in the transmission data memory 12, the data is packetized and the packet signal is transmitted, and if there is no significant data, the control signal detection section 18 outputs 18
In a cycle starting with -1, an invalid packet signal having the same length as the packet signal is set in the transmission data memory 12 and transmitted in order to maintain the acquired highest priority transmission right.

Further, in the period starting with the second trigger signal, that is, the period starting with the output 18-2 of the control signal detection section 18, if there is no significant data, no transmission is performed.

Next, communication control in the trigger station and node station will be explained. Figure 3 shows transmission line 6
FIG. 3 is a diagram showing the flow of the above signal, showing a certain multi-period and the first period of the next multi-period. Now, assume that at the start of a certain multi-cycle, node station 1 has already acquired the right to transmit with the highest priority, and node stations 3 and 4 newly desire transmission with the highest priority. When the trigger station 5 sends a trigger signal TGI indicating the start of the first cycle of the multi-cycle and polling the communication with the highest priority to the transmission line 6, only the node station 1 that has already acquired the transmission right transmits the packet signal. S1 is sent.

In this case, if there is significant data to be sent, it is packetized and sent as a packet signal S1, but even if there is no significant data to be sent, the packet signal is is sent to the transmission line 6.

Trigger station 1.

When polling with the highest priority is completed, a polling signal POL is sent out to poll the communication with the second priority. With the second priority, node station 3.4, which newly wishes to communicate with the highest priority, sends packet signal 83.
°, 84'.

This packet signal S3', packet length of 34 degrees is the packet signal 33, S4 sent out after acquiring the highest priority.
Make it the same as. In FIG. 3, the node station 3.4 receives a packet signal 33'.

84'' within the first period, the highest priority has been acquired.In other words, in the present invention, the i recontrol of the transmission right at the highest priority, which was performed every period in the conventional technology, is This is performed only in the first period of the multi-period.The node station that cannot transmit in the second (Ji) priority of this first period cannot acquire the transmission right with the highest priority, and does not receive the highest priority transmission right until the first period of the next multi-period. Communication to acquire priority is prohibited. Therefore, in the remaining cycles of the multi-cycle, that is, the second, third, etc. cycles, the right to transmit with the highest priority is newly acquired. There are no node stations to do so.

As a result, in these remaining cycles, the node station that has acquired the highest priority does not need to transmit every cycle to secure the right to transmit with the highest priority, unlike in the prior art, and has no meaningful information to transmit. You only need to send it if you have data. FIG. 3 shows an example in which node station 1.3 performs transmission in the second period, and node station 3.4 performs transmission in the third period. In the first period of the next multi-period, communication to obtain the highest priority is performed by polling of the second priority.
The node station that has acquired the highest priority transmission right transmits the packet signal S regardless of whether there is data to be transmitted.
l, S3. Send S4.

〔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 the drawing]

Figure 1 is a diagram showing the configuration of the trigger station and node station, Figure 2 is a diagram showing the frame configuration of a packet signal,
5 and 5 are diagrams showing the flow of signals, and FIG. 4 is a diagram showing the configuration of the loop network. 1, 2.3.4... Node station 5
・・・・・・・・・・・・ Tricaste John 6 ・
・・・・・・・・・・・・ Transmission line 11 ・・・・・・
...... Transmission control section 12 ......
... 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 51 ......
- Control signal transmitter 52 ......
Timer agent Patent attorney Yoshiyuki Iwasa (a) ([)) Figure 1 Figure 4 (a) (b) Figure 5

Claims (2)

[Claims] (1) A trigger station and a plurality of node stations are connected in a loop, and the trigger station is
In a loop 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. 1 and a second trigger signal are provided, and only in the cycle in which the trigger station sends out the first trigger signal, a node station that newly desires to perform transmission with the highest priority attempts transmission in order to acquire the transmission right. If the transmission is successful, the node station acquires the highest priority transmission right, and once the highest priority transmission right is acquired, the node station should transmit in the cycle in which the trigger station transmits the first trigger signal. If there is a significant signal, the signal is transmitted, and if there is no significant signal, an invalid signal is transmitted to maintain the transmission right, and in the period in which the trigger station transmits the second trigger signal. A highest priority communication method in a loop network, characterized in that when there is a significant signal to be transmitted, such a signal is transmitted, and when there is no significant signal to be transmitted, no transmission is performed. (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.