JPS622748A - Flow control system - Google Patents

Abstract

PURPOSE:To reduce the overhead for communication control and to improve the throughput for high-speed communication of a large quantity of data, by separating the error control from the flow control and performing the flow control through the communication controllers at the transmitter and receiver sides respectively. CONSTITUTION:A comparison means 5 of a communication controller 1 at the transmitter side performs the flow control so that the data are transferred to the receiver side from a terminal equipment 2 at the transmitter side while the quantity of the data transferred to a transmission buffer 6 of the controller 1 is controlled. Thus the error control is separated from the flow control and the overhead of the communication control is reduced together with improvement of the transmission throughput. Furthermore it is possible to receive the data of a large quantity in terms of burst when viewed from a reception terminal equipment 4 without producing the overflow to the reception buffer of a communication controller 3 at the receiver side.

Description

[Detailed Description of the Invention] (Summary) In a data communication system, error control and flow control are separated and the flow control is performed by a transmission side communication control device.This reduces the overhead required for communication control, Establish a high-speed, large-capacity communication system by improving transmission throughput.

[Industrial application field]

The present invention relates to a flow control method, and in particular, in a flow control method communication system in which error control and flow control are separated and the flow control is performed by a communication control device on the sending side, communication is performed in units of communication data (packet). There is something. In such systems, error control, flow control, etc. must be performed to ensure that the communication is completed as desired.

Such control involves overhead that degrades communication performance, and is therefore a major problem that must be solved, especially in high-speed, large-capacity communication.

[Conventional technology]

In a conventional communication system in which communication is performed in units of communication data, error control and flow control are performed integrally for each unit of communication data, and when an error is detected, data is retransmitted for correction.

[Problem that the invention seeks to solve]

Therefore, the overhead of error detection not only causes a decrease in transmission throughput (but also, when an error is detected, the flow is automatically suppressed because the above-mentioned retransmission process is involved).

Such defects are a major factor that prevents the above-mentioned method from being applied to high-speed, large-capacity communications.

The present invention was created in view of the above-mentioned problems, and an object of the present invention is to provide a flow control method that can communicate large amounts of data at high speed.

[Means for solving problems]

FIG. 1 shows a block diagram of the principle of the present invention. The present invention is an i11 system in which the data transfer speed between a communication control device and a terminal device connected thereto is slower than the data transfer speed between i1m communication control devices. The main parts of the communication system are structured as follows.

That is, the communication control device of the above system has a data transfer rate between the transmitter 1'1 communication control device (1) and one terminal device (2), and a data transfer rate between the receiving side communication control device (3) and one terminal device (4). A comparison means (5) is provided to compare the ratio of the comparison means (5)! 2. Data transfer amount control means (7) is provided for setting the data transfer amount from the sending terminal device (2) to the sending buffer (6) of the sending side communication control device (1) according to the result. It is composed of

[Effect]

In the above communication system, the transmission side communication control device (
Data is transferred to the receiving side while controlling the amount of data transferred from the sending terminal device (2) to the sending buffer (6) of the sending side communication control device (1) by the comparing means (5) of 1). Such flow control is performed.

By doing this, error control and flow control are separated, the overhead spent on communication control is reduced, transmission through-boot is improved, and the reception buffer of the receiving side communication control device is prevented from overflowing. To enable burst reception of large amounts of data from the perspective of a receiving terminal.

〔Example〕

FIG. 2 shows the overall configuration of an embodiment of the present invention, and details of its main parts are shown in FIG. 3. In FIG. 2, 100 is a transmission side communication control device (node), and 110 is a transmission side terminal device (terminal).

Further, 200 is a receiving side communication control device (node), which is connected to the transmitting side communication control device 100 via a transmission path 300. 210 is a receiving terminal device.

The transmitting side communication control device 100 has a configuration as shown in FIG. In FIG. 3, 10 is a microprocessor unit (MPIJ), which resets the transfer data count circuit 20 to start counting at the start of data transfer. When the data is transferred to the transmission buffer 30, the count value is sent to the count comparison circuit 40. At the start of data transfer, the MPU10 also performs a specified transfer that is transferred from the sending terminal device 110 in one cycle as will be described later. The number of bytes Ns is sent to the count comparison circuit 40. In response to the output signal from the count comparison circuit 40, 50 transmits whether data transfer is possible (J11 terminal equipment 51
10 is a data transfer permission/rejection flag circuit. In addition, the MPU 10 refers to the receiving terminal capability storage memory 60 using the destination receiving terminal device address, and records the above-mentioned byte RN S and the time from the end of one cycle transfer to the start of the next transfer. The time pTs is read out, Ns is set in the count comparison circuit 40, and T is set in the quimuff 0.

The transmitting side terminal device 110 notifies MPU10 of a communication cefsilane end signal when all data transfer is completed.

Further, the transmitting terminal device 110 can rewrite the capabilities of the receiving terminal device in the memory 60. These are indicated by θ in FIG.

A flow control aspect of the present invention configured as described above will be explained below.

Before communication from the transmitting terminal device 110 to the receiving terminal device 21O is started, the data transfer permission/rejection flag circuit 50 is in a state of refusing data transfer from the transmitting terminal device 110 (st).

pO).

Then, the transmitting side terminal device 110 and the receiving side terminal device IZ2
When a session is established to start communication with 10 (step 1), MPUI O refers to the receiving terminal capability storage memory 60 using the receiving terminal device address of the transmission destination and stores the number of bytes Ns. and the time interval Ts, and set N5 in the count comparison circuit 40 and Ts in the timer 70 (Step 2).

After that, MPU10 starts the transfer data count circuit 20.
Reset and start this.

As a result, the data transfer permission/rejection flag circuit 50 sends the data transfer permission state from the sending terminal bag 'f1110 to the sending terminal bag HIIO, so that the data transfer permission/rejection flag circuit 50 sends the data transfer permission status from the sending terminal bag 'f1110 to the sending terminal bag HIIO.
The floor device 110 starts data transfer to the transmission buffer 3o (step 3).

When the transfer data count circuit 2o counts up to the specified number of transfer bytes, the count comparison circuit 40 sets the data transfer permission/rejection flag circuit 50 to the sending terminal bag r.
f! llo is in a data transfer refusal state and notifies the sending terminal device 110 of this state (step 4)
. This completes one cycle of data transfer.

At the end of this process, MPU10 resets and starts the timer 7o (step 5).

When the timer 70 measures the time Ts, the timer 70 sends a message to that effect to MPU10.
, and return to step 3 to repeat the same process.

Then, when the transmitting terminal device signals the completion of transfer of all transmission data, the communication session ends.

In such data transfer, transmission (J, l
When the data transfer speeds between the J terminal equipment and the transmitting side communication control device, the transmission path, and the receiving side communication control device and the receiving side terminal device are respectively vs, V, J, and VR, VN>>VS, V
The system is configured as shown in R, and when (11V s≦VR), the transmitting side communication control device transmits data N s and T s regarding the receiving side terminal device as N5 = (
1), Ts=0, and [2) When VS>VR, the transmitting side communication control device sends data Ns, Ts regarding the receiving side terminal device [where CBR is the reception buffer size of the receiving side communication control device] . ] By having it as a terminal device, data can be constantly transferred to the receiving terminal device without causing an overflow in the receiving buffer of the receiving side communication anti-aircraft weapon.

Therefore, from the perspective of the receiving terminal device, a similar burst transfer is performed, and the overflow caused by flow control for each data communication unit (packet) can be reduced, and communication throughput can be improved.

In addition, as mentioned above, reception (11 terminal capabilities), 8 storage memories, 6
By rewriting the contents of 0 at the time of establishing a session for starting communication, the transmitting side communication control device can perform flow control and obtain the same effect even when there is a change in the data transfer rate VR.

In addition, when there are multiple receiving side terminal devices, the data transfer rate VRI between each receiving side communication control device and the receiving side terminal device,
Among VR2,..., the receiving buffer size CBR7°CBR2,... of VR+ and receiving side communication control device is the highest.
・Ns with the smallest CBRJ as a parameter,
Similar flow control can be performed by determining Ts.

〔Effect of the invention〕

As explained above, according to the present invention, error control and flow control are separated, and the flow control is performed by the communication control device on the transmitting and receiving sides, thereby reducing the overhead for communication control and increasing the throughput. can transmit large amounts of data at a high speed of 1M.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is an overall configuration diagram of an embodiment of the present invention, and FIG. 3 is a detailed diagram of the main part of FIG. 2. In FIG. 1, 1 is a transmission side communication control device, 2 is a transmission side terminal device, 3 is a reception side communication control device, 4 is a reception side terminal device, 5 is a comparison means, 6 is a transmission buffer, and 7 is a data transfer amount It is a control means.

Claims (2)

[Claims] (1) In a data communication system configured such that the data transfer rate between a communication control device and a terminal device connected thereto is slower than the data transfer rate between the communication control devices,
a comparing means (5) for comparing the data transfer rate between the sending side communication control device (1) and the terminal device (2) and the data transfer rate between the receiving side communication control device (3) and the terminal device (4); The transmitting terminal device (
2) to the transmission buffer (6) of the transmission side communication control device (1).
). A flow control system comprising: a data transfer amount control means (7) for setting the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount to the data transfer amount. (2) The flow control method according to claim 1, wherein the data transfer rate to be compared can be set arbitrarily.