JP2682491B2 - Access control method in network having distributed buffer memory - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an access control method in a packet switching network when communication packet buffer memories are distributed over a long distance or when communication buffer memories are not arranged in the network. .

[0002]

2. Description of the Related Art A LAN (Local Area) using a wireless technology has been required to transmit and receive data via a high-speed network with the progress of information society.
In a network environment or a LAN environment using optical transmission technology or optical switching technology, there is generally no buffer memory for storing communication packets in the network. Therefore, in the case of a collision retransmission type access control method, such as a random access control method, in which when a communication packet occurs in a certain terminal, the packet is independently transmitted on demand, contention occurs in the network and throughput is reduced. I will end up.

For the purpose of preventing the reduction of the throughput, a reservation type access is provided in which a controller for managing communication is arranged in the central part of the network and a communication reservation is made before transmission of a communication packet on a transmission path to avoid a collision. A polling access control method, which is a control method, is used.

Generally, in a wireless LAN via a satellite or an optical network for transferring packets at a very high speed, the propagation delay time due to the communication distance is longer than the transmission time of one packet. For this reason, when a packet is generated as in the polling access control method, an application for securing a communication path is made to the controller, and the packet is transmitted after receiving the result, the packet delay time increases. Due to the influence, the random access control method has a smaller average delay time of packets when the load is particularly low. Therefore, when the network load is low, the random access control method is used, and when the load is high, the access control method that uses the polling access control method is the "slot aloha communication system".
(Japanese Patent Laid-Open No. 2-69030) and the like.

FIG. 1 shows an example of the configuration of a network that employs such an access control method.

The network has input ports 103-104.
Controller 115 Switch 126 Output port 1
27-128. Input port 103
-104 is a buffer memory 105-106, a memory controller 107-108, a transmitter 109-110, 1
11-112 and receivers 113-114. The controller 115 includes receivers 116-117, transmitters 118-119, buffer memories 120-121, access control method switching discriminators 122-123, an arbiter 124, and a switch driver 125.
The output ports 127-128 are composed of receivers 129-130, buffer memories 131-132, and transmitters 133-134.

There are a random access control method and a polling access control method as access control methods, which are switched according to the average delay time of packet signals or the average number of retransmissions.

In the case of the random access control method, the packet signals from the input lines 101-102 are stored in the buffer memory controllers 107-108 and the input buffer memory 105.
-106 is input. Input buffer memory 105-1
From 06, a packet signal and a control packet signal are read according to the control signals of the buffer controllers 107-108. Packet signals are sent from the transmitters 109-110 to the switch 126. Also, the transmitter 111-11
A control packet signal is transmitted from the receiver 2, and the receiver 116-
It is input to the access control method switching discriminator 122-123 via 117 and the buffer memories 120-121. Access control method switching discriminator 122-123
Detects the network residence time or the number of retransmissions added to the control packet signal, averages these numerical values, and compares the numerical value with a preset value.

Access control method switching discriminator 122-
When the numerical value detected by 123 is smaller than the preset value, a control signal is sent to the arbiter 124. Arbiter 12
4 performs arbitration using the control signal. The arbiter 124 receives an ACK (Acknowledgement) when the packet signal can be sent to the desired output port.
t), NACK if the packet signal cannot be transmitted
(Nonknowledgement) is written in the control packet signal, and the access control method switching discriminator 1
22-123. Furthermore, the arbiter 124 is
When returning CK, through the switch driver 125,
The switch 126 is switched. AC from arbiter 124
The control packet signal including K / NACK is transmitted by the transmitter 116-
117 and the receiver 113-114, and is sent to the buffer memory controller 107-108. When the buffer memory controller 107-108 receives the control packet signal including ACK, the input buffer memory 105-10 is received.
The packet signal corresponding to the control packet signal is deleted from 6. In addition, the buffer memory controller 107-
Upon receiving a control packet signal including NACK, 108 retransmits the packet signal.

Access control method switching discriminator 122-
When the value detected by 123 exceeds a preset value, the arbiter 124 is notified of a request for switching to the polling access control method, and the arbiter 124 switches to the polling access control method, and all the input ports 103-104.
Notify to

In the polling access control method, the input port 103-104 reads the control packet signal from the buffer memory 105-106 prior to the packet signal transmission, outputs the control packet signal from the transmitter 111-112, and outputs the control signal to the receiver 1.
16-117 through arbiter buffer memory 120-1
21. Arbiter buffer memory 120-1
The data is read out from No. 21 according to the input order and sent to the access control method discriminators 122-123. The access control method switching discriminators 122-123 detect the average delay time or the average number of retransmissions of the packet signal added to the control packet signal, and average them.

Access control method switching discriminator 122-
If the value detected at 123 exceeds the preset value, the control packet signal is sent to the arbiter 124. The arbiter 124 makes a connection reservation using the control packet signal, writes an ACK in the control packet signal when the packet signal can be sent to the desired output port, and transmits the control packet signal from the transmitter 118-119 to the receiver 11.
It sends to 3-114. Further, the arbiter 124 switches the switch 126 through the switch driver 125. The control packet signal added with ACK is the receiver 11
It is sent to the controller 107-108 via 3-114. Controllers 107-108 send out packet signals corresponding to the control packet signals and erase the packet signals from input buffer memories 105-106.

Access control method switching discriminator 122-
If the value detected at 123 is less than the preset value, the control packet signal notifies the arbiter 124 of switching to the random access control method. Arbiter 12
4 is the input port 10 for switching to the access control method.
3-104 is notified and the access control method is switched.

The packet signal passing through the switch 126 passes through the receivers 129-130 and the output buffer memory 131.
-132 is input. Output buffer memory 131-1
From 32, a FIFO (First-In-First-
The packet signal is output by the Out method (a method of outputting according to the input order).

By using such an access control method that uses both the random access control method and the polling access control method, the packet signal having a small average delay time is transferred by the random access control method when the network load is small. When the network load is high, the polling access control method can improve the throughput.

[0016]

In the conventional method, the load on the network is predicted by predicting the load on the network based on the average delay time of packet signals or the average number of retransmissions and switching between the random access control method and the access control method. The random access control method used when the value is low has a smaller average delay time or average number of retransmissions of the packet signal than the access control method. However, since the load is low, the probability of occurrence is low, but when contention occurs in the network and retransmission is performed, the time multiplied by the number of retransmission times of the propagation delay time is added, and the delay time of the packet signal with many retransmission times and the number of retransmission times are small. The difference in the delay time of packet signals becomes large. That is, in the conventional access control method using both random access and polling, when the random access control method is used, the average delay time is small, but the delay time dispersion is large. When a certain one terminal collects and processes packet signals from a plurality of terminals connected to the network, or when a process is synchronized among a plurality of terminals, the processing start time is determined by the final arrival packet signal. The conventional access control method in which the delay time of the packet signal is widely dispersed has a problem that the processing start time is delayed.

An object of the present invention is to provide a network in which buffer memories are physically distributed and a propagation delay time of a packet signal to a receiver is longer than one packet signal transmission time, or a network in which no buffer memory is arranged. An object of the present invention is to provide an access control method for reducing the average / dispersion of the delay time of packet signals.

[0018]

According to a first network access control method of the present invention, a plurality of input devices capable of temporarily storing and transmitting data packet signals and a plurality of output devices capable of temporarily storing and receiving the data packet signals are physically connected. Of the plurality of input devices and the plurality of output devices, and a path control device that switches the switches according to destination information of the data packet signal. A first control packet signal for preliminarily reserving the route setting is sent from the input device to the route control device, the route of the switch is switched by the first control packet, and then the data packet signal is transmitted to the output device. Reservation access control method to send, and request for immediate setting of route setting from each of the plurality of input devices to the route control device When the second control packet and the data packet signal are transmitted to the output device and the route can be set, the route of the switch is switched and the data packet signal is transmitted to the output device and the route cannot be set. In the network access control method using the second control packet signal and a retransmission type access control method for retransmitting the data packet signal together, in the case of the retransmission type access control method, the destination information of the data packet signal is The network dwell time after the data packet signal is input to the input device is recorded, and when the network dwell time of each data packet signal exceeds a preset time, the retransmission type access control method If the reservation access control method is used, Also records the network residence time after the data packet signal is input to the input device in the destination information of the data packet signal, and the average time of the network residence time of the data packet signal exceeds a preset time. When the reserved access control method is changed to the retransmission type access control method, the route of the switch of the data packet signal exceeding the set time of the network residence time is reserved and the data packet signal is transmitted early. In addition, the data is transmitted from the input device to the output device.

The second network access control method of the present invention is, in the case of the retransmission type access control method, the number of retransmissions after the data packet signal is input to the input device as destination information of the data packet signal. Recording, when the number of retransmissions of each of the individual data packet signals exceeds a preset numerical value, transition from the retransmission access control method to the reserved access control method, in the case of the reserved access control method, When the number of retransmissions after the data packet signal is input to the input device is recorded in at least the destination information of the data packet signal, and the average of the number of retransmissions of the data packet signal exceeds a preset numerical value. Then, the reserved access control method is changed to the retransmission type access control method, and the number of retransmissions is set. Book the path of said switch of said data packet signals exceeding the serial numerical characterized by sending to the output device from the input device at an early stage the data packet signal.

[0020]

The access control method of the present invention is an access control method that uses both a random access control method and a polling access control method when the delay time of a packet signal transmitted from a certain terminal becomes large. The average delay time and the average delay time can be reduced by reducing the average delay time by using the random access control method and reducing the average delay time when the average delay time becomes large.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the network access control method of the present invention will be described with reference to FIGS.

FIG. 2 is a block diagram of a network for carrying out the access control method of the present invention. An example is the case of two terminals.

The network has input ports 203-204.
And controller 215, switch 228 and output port 2
29-230. Input port 203
-204 is a buffer memory 205-206, a memory controller 207-208, a transmitter 209-210, 2
11-212 and receivers 213-214. The controller 215 includes a receiver 216-217, a transmitter 218-219, a buffer memory 220-221, a delay time measuring unit 222-223, and a counter 224-225.
And an arbiter 226 and a switch driver 227. Output ports 229-230 are receivers 231-2
32, buffer memory 233-234, and transmitter 235-
And 236.

The packet signals from the input lines 201-202 are input to the memory controllers 207-208 and the input buffer memories 205-206. From the input buffer memory 205-206 to the memory controller 207-20
The packet signal and the control packet signal are read out according to the control signal of No. 8. A packet signal is sent from the transmitters 209-210 to the switch 228. In addition, the transmitter 21
The control packet signal is transmitted from 1-212, and the receiver 2
16-217, then arbiter buffer memory 220-
221 is input. Arbiter buffer memory 220-
The control packet signal read from 221 is the counter 2
After being sent to 24-225, it is sent to the arbiter 226. The arbiter 226 performs arbitration using the control packet signal. The arbiter 226 writes ACK in the control packet signal when the packet signal can be sent to the desired output port and NACK in the case where the packet signal cannot be sent, and sends the control packet signal to the delay time measuring units 222-223. To do. Delay time measuring device 22
2-223 compares the input time of the packet signal with the current time, calculates the delay time and the average delay time of the packet signal, and compares those times with a reference value to switch the access control method. The control packet signal transmitted from the delay time measuring unit 222-223 passes through the transmitters 218-219 and the receivers 213-214, and then the buffer controller 2
07-208.

The packet signal passing through the switch 228 passes through the receivers 231-232 and the output buffer memory 233.
-234 is input. Output buffer memory 233-2
From 34, a FIFO (First-In-First-
The packet signal is output by the Out method (a method of outputting according to the input order).

3 to 9 are flow charts for explaining the access control method of the present invention.

The flow chart of FIG. 3 shows from the packet signal input to the writing to the input buffer memories 205-206. The packet signal (301) from the input line 201-202 is input buffer memory controller 207-
Header analysis is performed at 208 (302). afterwards,
The output port of the packet signal is determined, and a sequential number managed for each output port is assigned (303) in order to guarantee the input time and the normal order arrival of each desired output port (303), and then to the input buffer memory 205-206. Is written (305).

The flow charts of FIGS. 4-5 show the reading of packet signals from the input buffer memories 205-206. FIG. 4 shows the case of the random access control method, and FIG. 5 shows the case of the polling access control method.

Upon receiving the control signal from the arbiter 226 (401), the memory controllers 207-208 detect the access control method added therein (40).
2). In the case of the random access control method, the control packet signal is stored in the memory controllers 207-208. The memory controllers 207-208 detect the ACK / NACK signals in the memory therein (40
3). The memory controllers 207-208, if those signals do not exist, input buffer memory 205-2.
Select the output packet signal according to the input order from 06,
A sending signal is sent to the packet signal and the control signal (40
5). When the ACK signal is present (404), the memory controllers 207-208 erase the packet signal corresponding to the ACK signal from the input buffer memories 205-206 (406). In case of NACK signal (4
04), at that time the input buffer memory 205-206
If the packet signal is not read from N,
The packet signal corresponding to the ACK signal is read and retransmitted. The memory controller 207-208 enters a waiting state for reading the packet signal corresponding to the NACK signal when the packet signal is being read from the input buffer memory 205-206, and the packet signal currently being performed. Will be sent as soon as
7).

Further, the memory controllers 207-208
When the signal transferred from the arbiter 226 to the polling access control method is received, the forcibly switches to the polling access method (401-402) and sends a packet signal based on the control signal (411). If another packet signal is being transmitted when the output signal is received (408), the packet signal being transmitted is canceled (410) and the packet signal based on the control signal is preferentially transmitted. The memory controllers 207-208 simultaneously send out the next packet transmission requests from the transmitters 211-212 to the controller 215 when the number of registered control packet signals for making a packet transmission request to the controller 215 is less than or equal to a specified value. As for this control packet signal, the control packet signal of the retransmission request is prioritized (414-41).
5). Further, the memory controllers 207-208 increment the number of registrations in the controller 215 (41
7) Then, the registered value and the specified value are compared again (413).

FIGS. 6-8 show control flowcharts in the controller 215.

The control packet signals from the input ports 203-204 are received by the receivers 216-217 (50).
1). In the case of the random access control method (502), the control packet signal is once sent to the arbiter buffer memory 220.
After being input (-503) to -221, the control packet signal is read from the arbiter buffer memory 220-221 according to the input order and sent to the counters 224-225. The counters 224-225 are arranged to output the sequential numbers of the control packet signals and their output ports 229-2.
If the values of the counters corresponding to 30 are compared (504) and they match, arbitration is executed in the arbiter 226 (505), and if they do not match, they are sent to the delay time measuring units 222-223. The arbiter 226 is
If the packet signal can be sent to the desired output port as a result of arbitration, ACK is written to the control packet signal, and if the packet signal cannot be sent to the desired output port, NACK is written to the control packet signal and the delay time is set. The control packet signal is sent to the measuring devices 222-223. The control packet signal sent to the delay time measuring devices 222-223 compares the input time of the packet signal with the current time, and if the delay time is within the reference value, the control packet signal from the transmitter 218-219. Is transmitted (508, 509). When sending a signal with ACK added, a control signal is sent to the switch driver 227 at the same time to drive the switch. If the delay time of the control packet signal is equal to or greater than the reference value, the polling access control method is shifted to (507), and a signal indicating the shift is sent to all input ports (510), and at the same time the control packet signal is transferred to the arbiter buffer. 222-223.

In the case of the polling access control method (50
In 2), the control packet signal received by the receiver 216-217 is stored in the arbiter buffer 220-221 (512). The arbiter buffers 220-221 select the optimum control packet signal based on the input time of the control packet signal and the sequential number (513,
514), the control packet signal is sent to the arbiter 226. The control packet signal is kept waiting until the connection between the input port and the output port indicated by the control packet signal can be secured in the arbiter 226 (515). When the connection is secured, the transmitter 218-2
An ACK signal is sent from 19. Then, it immediately shifts to the random access control method and notifies all input ports of the shift of the access control method, or shifts to the random access control method through the following procedure. The delay time measuring units 222-223 compare the input time with the current time (516). Calculate the average delay time. If the average delay time is equal to or less than the reference value, the control packet signal with ACK added is input using the polling access control method.
It is sent to 03-204. If it is equal to or larger than the reference value, the random access control method is switched (518) and the information is notified to all input ports (519). When the polling access control method is changed to the random access control method, the control packets stored in the arbiter buffers 220-221 are output to the delay time measuring units 222-223 according to the input order (522). The delay time measuring devices 222-223 measure the delay time of the control packet signal, and if the delay time is equal to or less than the reference value, NACK.
The control packet signal added with is sent to the input port 203-204 corresponding to the control packet signal. Also,
If the delay time of the control packet signal is the reference value or more, the access control method is switched to the polling method again (52
5), notify all the input ports 203-204 (52)
6).

FIG. 9 is a flowchart for writing / reading a packet signal from the output buffer memories 223 to 224 at the output port.

Output port 229 via switch 226
The packet signal sent to -230 is the receiver 231-
It is received at 232 (601), and the buffer memory 233-
It is input to 234 (602). Output buffer memory 2
The packet signals arriving at 33-234 are read out in the order of arrival (603) and output from the transmitters 235-236 to the output line 2
It is output to 37-238 (604).

In the above access control method, the reference time is set to the delay time and the average delay time of each packet signal. When the random access control method is used, each packet signal exceeds the reference delay time. In order to reduce the dispersion of the delay time and the polling access control method with a small delay dispersion, and when using the polling access control method, the average delay time immediately or when the packet signal exceeds the reference average delay time. To a random access control method with a small

As described above, the access control method of the present invention is
Both the random access control method and the polling access control method can be used together to reduce both the average delay time of packet signals and the variance of the average delay time.

Next, a second embodiment of the network access control method of the present invention will be described with reference to FIGS.

FIG. 10 is a block diagram of a network for carrying out the access control method of the present invention. Two terminals as an example
Is the case.

The network has input ports 703-704.
And controller 715, switch 728 and output port 7
29-730. Input port 703
-704 is a buffer memory 705-706, a memory controller 707-708, and a transmitter 709-710,7.
11-712 and receivers 713-714. The controller 715 includes receivers 716-717, transmitters 718-719, buffer memories 720-721, retransmission counters 722-723, counters 724-725, arbiter 726, and switch driver 727. Output ports 729-730 are receivers 731-73
2, buffer memory 733-734, and transmitter 735-7
36.

Packet signals from the input lines 701-702 are inputted to the buffer memory controllers 707-708 and the input buffer memories 705-706. The buffer controller 7 from the input buffer memories 705 to 706.
The packet signal is read according to the control signal of 07-708, and the packet signal is sent from the transmitters 709-710 to the switch 728. Also, control packet signals are transmitted from the transmitters 711-712, and the receivers 716-717
And is input to the arbiter buffer memory 720-721. The control packet signal read from the arbiter buffer memory 720-721 is the counter 724-725.
Then, it is sent to the arbiter 726. The arbiter 726 performs arbitration using the control packet signal. The arbiter 726 writes ACK in the control packet signal when the packet signal can be sent to the desired output port, and NACK in the case where the packet signal cannot be sent, and retransmits the control packet signal to the retransmission counter 722-.
723. Retransmission counters 722-723 calculate the number of retransmissions and the average number of retransmissions of the packet signal, and compare the number of times and a reference value to switch the access control method. The control packet signals transmitted from the retransmission counters 722-723 are transmitters 718-719 and receivers 713.
-714, and is sent to the memory controllers 707-708.

The packet signal passing through the switch 728 passes through the receivers 731-732 and the output buffer memory 733.
It is input to -734. Output buffer memory 733-7
From 34, a FIFO (First-In-First-
The packet signal is output by the Out method (a method of outputting according to the input order).

11 to 17 are flow charts for explaining the access control method of the present invention.

The flowchart of FIG. 11 shows from the packet signal input to the writing to the input buffer memories 705 to 706. The packet signals (801) from the input lines 701-702 are input buffer memory controller 707.
Header analysis is performed at -708 (802). After that, the output signal of the packet signal is determined, and a sequential number managed for each output port is given to guarantee the forward arrival of each desired output port (803), and the packet signals are input to the input buffer memories 705 to 706. It is written (805).

The flow charts of FIGS. 12 to 13 show the reading of packet signals from the input buffer memories 705 to 706. FIG. 12 shows the case of the random access control method, and FIG. 13 shows the case of the polling access control method.

Buffer memory controller 707-70
8 receives the control signal from the arbiter 726 (901)
And the access control method added therein is detected. In the case of the random access control method (902), the control signal is input to the input buffer memory controller 707-7.
It is stored in 08. Memory controller 707-708
Detects the ACK / NACK signal in the memory therein (903). The memory controllers 707-708 are
If those signals do not exist, the input buffer memory 7
An output packet signal is selected from 05-706 according to the input order, and a transmission signal is sent to the packet signal and the control signal (905). The memory controllers 707-708 are A
When the CK signal exists (904), the packet signal corresponding to the ACK signal is input to the input buffer memory 705-7.
It is erased from 06 (906). In addition, the memory controllers 707-708 can detect the NACK signal (9
04), at that time the input buffer memory 705-706
If the packet signal is not read from N,
The packet signal corresponding to the ACK signal is read and retransmitted. When the packet signal is being read from the input buffer memories 705 to 706, the reading of the packet signal corresponding to the NACK signal enters the waiting state, and the packet signal is transmitted as soon as the current packet signal transmission is completed. (907).

Also, the memory controllers 707-708.
When the signal transferred from the arbiter 726 to the polling access control method is received, the forcibly switches to the polling access method (901-907) and sends out a packet signal based on the control signal (911). If another packet signal is being transmitted when the control signal is received (908), the packet signal being transmitted is canceled (910), and the packet signal based on the control signal is preferentially transmitted. The memory controllers 707-708 simultaneously send the next packet transmission request from the transmitters 711-712 to the controller 715 when the number of registered control packet signals for requesting packet transmission to the controller 715 is less than or equal to a specified value. At this time, priority is given to the control packet signal of the packet transmission request for which the retransmission request is made (914-9).
15). The memory controllers 707-708 increment the number of registrations in the controller 715 (9
17) Then, the registered value and the specified value are compared again (913).

14 to 16 show control flowcharts of the controller 715.

The control packet signals from the input ports 703-704 are received by the receivers 716-717 (100
1). In the case of the random access control method (1002),
The control packet signal is temporarily transferred to the arbiter buffer memory 72.
After being input to 0-721 (1003), the control packet signal is read from the arbiter buffer memory 720-721 according to the input order, and the counter 724-725.
Sent to The counters 724-725 detect the sequential number of the control packet signal and its output port 729.
-Compare the values of the counter corresponding to -730 (1004)
If they match, arbitration is executed in the arbiter 726 (1005), and if they do not match, the data is sent to the retransmission counters 722-723. Arbiter 72
When the packet signal can be sent to the desired output port as a result of the arbitration, 6 writes ACK in the control packet signal, and when the packet signal cannot be sent to the desired output port, writes NACK in the control packet signal. , And sends the control packet signal to the retransmission counters 722-723. Retransmission counter 722-723
For the control packet signal transmitted to, the number of retransmissions and the average number of retransmissions are calculated, and if the number of retransmissions is within the reference value, the control packet signal is transmitted from the transmitters 718-719 (1008, 1009). When transmitting a signal with ACK added, a control signal is simultaneously transmitted to the switch driver 727 to drive the switch. If the number of times the control packet signal is retransmitted is equal to or greater than the reference value, the process shifts to the polling access control method (1007), and a signal indicating the shift is sent to all input ports (1010), and at the same time the control packet signal is transmitted to the arbiter buffer. 727-723.

In the case of the polling access control method (10
02), the control packet signal received by the receiver 716-717 is stored in the arbiter buffer 720-721 (1017). The arbiter buffers 720-721 are
An optimum control packet signal is selected based on the input time and the sequential number of the control packet signal (10
13, 1014) and the control packet signal is sent to the arbiter 726. Control packet signal is arbiter 726
In (1015), the process waits until the line reservation for the input port and the output port indicated by the control packet signal is made. When the line reservation is completed, the arbiter 726 sends ACK signals from the transmitters 718-719. afterwards,
Immediately shift to the random access control method and notify all input ports of the shift of the access control method, or shift to the random access control method through the following procedure. The retransmission counters 722-723 calculate the average of the number of retransmissions (1016). If the average number of retransmissions is less than or equal to the reference value, the retransmission access control method uses the polling access control method, and the retransmission counters 722-723 send control packet signals with ACKs to the input ports 703-704. If it is equal to or larger than the reference value, the method is switched to the random access control method (101
8) Notify all the input ports of the information (101
9). When the polling access control method is changed to the random access control method, the arbiter buffer 720-
The control packet stored in 721 is output to the retransmission counters 722-723 according to the input order (1
022). The retransmission counters 722-723 measure the number of retransmissions of the control packet signal, and if the value is less than or equal to the reference value, send the control packet signal with NACK added to the input ports 703-704 corresponding to the control packet signal. If the number of times the control packet signal is retransmitted is equal to or greater than the reference value, the access control method is switched to the polling method again (1024), and all the input ports 703 to 704 are notified (1026).

FIG. 17 shows the writing / writing of the packet signal from the output buffer memory 733-734 at the output port.
It is a flow chart of reading.

Output port 729 through switch 726
The packet signal sent to -730 is the receiver 731-
Received at 732 (1101), buffer memory 733
It is input to -734 (1102). The packet signals that have reached the output buffer memories 733-734 are read in the order of arrival (1103) and output from the transmitters 735-736 to the output lines 737-738 (1104).

In the above access control method, reference times are set for the number of retransmissions and the average number of retransmissions of each packet signal. When the random access control method is used, each packet signal exceeds the reference number of retransmissions. In order to reduce the dispersion of the delay time and the polling access control method with a small delay dispersion, and when the polling access control method is used, the average delay time immediately or when the packet signal exceeds the reference average number of retransmissions. To a random access control method with a small

As described above, the access control method of the present invention is
Both the random access control method and the polling access control method can be used together to reduce both the average delay time of packet signals and the variance of the average delay time.

[0055]

As described above, in the access control method of the present invention, the delay time of the packet signal transmitted from a certain terminal is increased in the access control method which uses both the random access control method and the polling access control method. In this case, the polling access control method is used to reduce the dispersion of delays, and when the average delay time becomes large, the random access control method is used to reduce the average delay time. Time dispersion can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram for performing a conventional access control method.

FIG. 2 is a configuration diagram for performing a first access control method of the present invention.

FIG. 3 is a flow chart for explaining a first access control method of the present invention.

FIG. 4 is a flow chart for explaining a first access control method of the present invention.

FIG. 5 is a flowchart illustrating a first access control method of the present invention.

FIG. 6 is a flowchart for explaining the first access control method of the present invention.

FIG. 7 is a flowchart illustrating a first access control method of the present invention.

FIG. 8 is a flowchart for explaining a first access control method of the present invention.

FIG. 9 is a flowchart illustrating a first access control method of the present invention.

FIG. 10 is a configuration diagram for performing a second access control method of the present invention.

FIG. 11 is a flowchart illustrating a second access control method of the present invention.

FIG. 12 is a flowchart for explaining a second access control method of the present invention.

FIG. 13 is a flowchart illustrating a second access control method of the present invention.

FIG. 14 is a flowchart illustrating a second access control method of the present invention.

FIG. 15 is a flowchart illustrating a second access control method of the present invention.

FIG. 16 is a flowchart illustrating a second access control method of the present invention.

FIG. 17 is a flow chart for explaining a second access control method of the present invention.

[Explanation of Codes] 101-102, 201-202, 701-702 Input line 103-104, 203-204, 703-704 Input port 105-106, 120-121, 131-132, 2
05-206, 220-221, 233-234, 70
5-706, 720-721, 733-734 Buffer memory 107-108, 207-208, 707-708 Memory controller 109-112, 118-119, 133-134, 2
09-212, 218-219, 235-236, 70
9-712, 718-719, 735-736 Transmitter 113-114, 116-117, 129-130, 2
13-214, 216-217, 231-232, 71
3-714, 716-717, 731-732 Receiver 115, 215, 715 Controller 172-173 Access control method switching discriminator 124, 226, 726 Arbiter 125, 227, 727 Switch driver 126, 228, 728 Switch 127-128 , 229-230, 729-730 Output port 133-134, 237-238, 737-738 Output line 224-225, 724-725 Counter 722-723 Retransmission counter

Claims (2)

(57) [Claims] 1. A plurality of input devices capable of temporarily storing and transmitting a data packet signal and a plurality of output devices capable of temporarily storing and receiving the data packet signal are physically distributed, and the plurality of input devices and the plurality of outputs are arranged. A switch that connects the device and a route control device that switches the switch according to destination information of the data packet signal, and reserves route setting from the plurality of input devices to the route control device in advance. A reserved access control method for transmitting a data packet signal to the output device after transmitting a control packet signal of No. 1 and switching the route of the switch by the first control packet; and a route from each of the plurality of input devices. A second control packet requesting the controller to immediately set the route setting and the data packet signal are output by the output device. To the output device, the path of the switch is switched, and the data packet signal is sent to the output device. When the path cannot be set, the second control packet signal and the data packet signal are retransmitted. In the network access control method used in combination with the retransmission type access control method, the network residence time after the data packet signal is input to the input device in the destination information of the data packet signal In the case of the reserved access control method, when the network retention time of each data packet signal exceeds a preset time, the retransmission type access control method is switched to the reserved access control method. , At least the destination information of the data packet signal is the data packet signal Records the network residence time since the input to the input device, and when the average time of the network residence time of the data packet signal exceeds a preset time, the reservation access control method uses the retransmission type Transitioning to an access control method, reserving a path of the switch of the data packet signal that exceeds the set time of the network residence time, and sending the data packet signal from the input device to the output device early A network access control method characterized by: 2. In the case of the retransmission type access control method, the number of retransmissions after the data packet signal is input to the input device is recorded in the destination information of the data packet signal, and the number of retransmissions of each data packet signal is recorded. When the number of retransmissions exceeds a preset numerical value, the retransmission access control method shifts to the reserved access control method, and in the case of the reserved access control method, at least the destination information of the data packet signal is the data packet. The number of retransmissions after the signal is input to the input device is recorded, and when the average of the number of retransmissions of the data packet signal exceeds a preset numerical value, the retransmission access from the reserved access control method is performed. The control method is started, and the switching of the data packet signal in which the number of retransmissions exceeds the set numerical value is performed. Network access control method according to claim 1, wherein the sending from the input device at an early stage the data packet signal to the output device path reserves a.