JPH06252938A - Data transmission control system - Google Patents

Abstract

PURPOSE:To provide a data transmission control system which can transmit the data at each cell transmission rate in response to the change of the network state, can improve the availability of a transmission line, and also can prevent the loss of cells. CONSTITUTION:A reception state detecting part 12 detects the reception state of data from an ATM network 30. A cell transmission interval control part 23 calculates the cell transmission interval information based on the information on the detected data reception state and a relational expression stored previously. Then a cell transmission interval adjusting part 22 adjusts the cell transmission interval information and reads the transmission data out of an FIFO buffer 21 to send them to the network 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multipoint PVC (Permanent Virtual Con) on an asynchronous transfer mode network (ATM network).
control the transmission rate of cells (including what are called "packets" in this specification) when the data transmitting / receiving terminal transmits transmission data to the network in the case of performing broadcast communication using The present invention relates to a data transmission control method.

[0002]

2. Description of the Related Art Conventionally, data transmission control systems include a leaky bucket type rate control system in an ATM network and a time flow rate control system as cell transmission rate control systems.

First, a leaky bucket control system in an ATM network will be described. FIG. 4 is a block diagram of a conventional data transmission control method.

In FIG. 4, a data transmission / reception terminal 10A
Is a FIFO (First-
In First-Out) buffer 21, counter 2
5 and a cell transmission rate control unit 20A including a cell transmission control unit 24A for transmitting cells to the ATM network 30.

Next, the operation of the conventional leaky bucket rate control system will be described. The cells arriving at the cell transmission rate control unit 20A are temporarily stored in the FIFO buffer 21. The cell is AT immediately after the start of the transmission unit time
When sent to the M network 30, the value of the counter 25 is increased by T (counter increase value), and the value of the counter 25 is decreased by N (N <T: counter decrease value) immediately before the end of each transmission unit time. However, the upper limit of the value of the counter 25 is U
If (U ≧ T + N−1) and the value of the counter 25 cannot be increased, the cell is made to wait in the FIFO buffer 21. If the lower limit of the value of the counter 25 is set to 0 and the value of the counter 25 cannot be decreased by N, the value of the counter 25 is held as it is. This operation controls the cell transmission rate.

Next, a time flow control method in the conventional ATM network will be described. FIG. 5 is a block diagram of another conventional data transmission control method. Figure 5
In the data transmission / reception terminal 10B, the FIFO buffer 21, the token pool 26 (size N), which is a means for accumulating tokens, and the cells are stored in the ATM network 30.
The cell transmission rate control unit 20B is composed of the cell transmission control unit 24B for transmitting to

Next, the operation of the conventional time flow rate control system will be described. The cell arriving at the cell transmission rate control unit 20B is temporarily stored in the FIFO buffer 21,
Immediately after the start of the transmission unit time, the number of tokens in the token pool 26 is reduced by one and the token is transmitted to the ATM network 30. If there are no tokens in the token pool 26, the cell is kept waiting in the FIFO buffer 21 until a token is generated. In addition, the token pool 26 is filled with tokens every certain fixed time (K transmission unit time). By this operation, it is possible to limit the number of cells transmitted to the ATM network 30 to N within the interval (K transmission unit time) in which a token is generated.

[0008]

However, in such a conventional data transmission control method, the data transmission / reception terminal follows the predetermined algorithm regardless of whether the leaky bucket type rate control method or the time flow rate control method is used. Since it has a configuration for controlling the cell transmission rate, it is not possible to send cells at a cell transmission rate that follows changes in the state of the network. As a result, in order to transmit cells at the cell transmission rate specified in advance, it is impossible to use the available network bandwidth to the maximum when the traffic of the network is reduced, and There was a problem that the utilization rate of was worse.

Further, when the traffic of the network becomes large such that a plurality of data transmission / reception terminals are transmitting cells in order to transmit cells at a cell transmission rate defined in advance, the plurality of data transmission / reception terminals are There has been a problem that the amount of cells sent out exceeds the capacity of the buffer existing in the network, and cells that cannot be stored in the buffer are lost.

The present invention solves the above problems.
An object of the present invention is to provide a data transmission control method capable of following a change in the state of the network, transmitting at a cell transmission rate suitable for the state, having a high transmission line utilization rate, and having no cell loss. .

[0011]

SUMMARY OF THE INVENTION The present invention is a data for broadcasting data divided into cells of a communication unit via an asynchronous transfer mode network to all valid data transmitting / receiving terminals belonging to the network. In the transmission control method, each data transmission / reception terminal includes a storage unit that temporarily stores data divided into cells, and a reception state detection unit that detects a reception state of the data divided into cells from the asynchronous transfer mode network. A cell transmission interval control unit that calculates cell transmission interval information based on the reception state information detected by the reception state detection unit; and a cell transmission interval that is adjusted by the cell transmission interval information of the cell transmission interval control unit. And a cell sending interval adjusting unit for reading the contents of the above and sending them to the asynchronous transfer mode network.

Further, according to the present invention, the cell transmission interval control unit stores a relational expression between the number of received cells per unit time received from the asynchronous transfer mode network and a cell transmission interval to be transmitted, and the relational expression is stored. And means for calculating cell transmission interval information based on the reception state information.

[0013]

The reception state from the asynchronous transfer mode network is detected, the cell transmission interval information is obtained using the detected reception state information (for example, the number of reception cells per unit time), and this cell transmission interval information is used as the cell transmission interval information. Based on this, the transmission data is sent to the network. As a result, it is possible to follow a change in the state of the network and to transmit at a cell transmission rate suitable for that state, so that the utilization factor of the transmission path becomes high and cell loss can be prevented.

[0014]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a data transmission control system according to an embodiment of the present invention. In FIG. 1, the data transmission control system includes a plurality of data transmission / reception terminals 10 that perform broadcast communication of data divided into cells of communication units via an asynchronous transfer mode network (ATM network) 30.

A feature of the present invention is that each data transmission / reception terminal 10 has a FIFO buffer 2 as a storage means for temporarily storing data divided into communication-unit cells.
1, a reception state detection unit 12 for detecting the reception state of data divided into cells from the ATM network, and a cell transmission interval for calculating cell transmission interval information based on the reception state information detected by the reception state detection unit 12. It includes a control unit 23 and a cell transmission interval adjustment unit 22 for adjusting the cell transmission interval according to the cell transmission interval information of the cell transmission interval control unit 23, reading the contents of the FIFO buffer 21 and transmitting it to the ATM network 30. .

The cell transmission interval control unit 23 stores a relational expression between the number of received cells per unit time received from the ATM network 30 in advance and the cell transmission interval to be transmitted, and the relational expression and the reception status information are stored in the relational expression. A means for calculating cell transmission interval information based on the above is included.

The operation of the data transmission control system having such a configuration will be described. Here, the ATM network is premised on a broadcast network in which a cell input from a certain terminal is distributed to all other terminals. That is, since cells from all other terminals arrive at a certain terminal, the number of cells flowing in the entire network can be known only by detecting the number of cells received by the terminal itself.

FIG. 2 is a graph showing the relational expression of the cell transmission interval with respect to the reception state of the data transmission control method of the present invention. In FIG. 2, Smax is the maximum cell transmission interval, Sm
in is the minimum cell interval, Rmax is the maximum number of received cells, and Rth is the threshold number of received cells. Next, the operation of the data transmission control device will be described. The cell arriving at the cell transmission rate control unit is stored in the FIFO buffer 21. The reception state detection unit 12 detects the reception state at certain time intervals, the cell transmission interval control unit 23 calculates cell transmission interval information based on the detected reception state information, and the cell transmission interval adjustment unit 22 calculates the cell transmission interval. The cell sending interval is adjusted according to the information, and the cells are read from the FIFO buffer 21 and sent to the ATM network 30.

Next, the calculation of cell transmission interval information by the cell transmission interval control unit will be described. An example thereof is shown in FIG. The reception state detection unit 12 counts the number of cells (the number of reception cells) received during a unit time. The cell transmission interval control unit 23 calculates a cell transmission interval corresponding to the number of reception cells shown in FIG. 2 from the number of reception cells.
The relational expression in FIG. 2 will be described. In a region where the number of received cells exceeds the received cell number threshold Rth, the cell transmission interval is linearly increased depending on the number of received cells.

The present invention can be used in packet switched networks. At this time, "ATM network" is read as "packet network" and "cell" is read as "packet". Further, the present invention is directed to a network that divides data into “units for dividing transmission data” and asynchronously transmits the data (eg, a cell relay network or an SMDS (Switchc).
hed Multi-megabit Data Se
network) etc.].

Further, the relational expression showing the cell transmission interval with respect to the number of received cells shown in FIG. 2 can be expressed by any other relational expression.

FIG. 3 is a graph showing the relational expression of the cell transmission interval with respect to the reception state of the data transmission control method according to another embodiment of the present invention, and shows an example of the relational expression increasing quadratically. Explaining the relational expression in FIG. 3, in the area where the number of received cells is equal to or smaller than the threshold Rth of received cells, the cell transmission interval is set to the minimum cell transmission interval Smin. The number of reception cells increases quadratically (solid line or broken line in the figure) depending on the number of reception cells. Different functions may be used for increasing and decreasing. Other reception state information can be used by setting the "reception cell number", which is the information expressing the reception state (reception state information), to the "reception cell interval" or the like.

[0023]

As described above, according to the present invention, the data transmission / reception terminal follows the state of the network and is suitable for the state by detecting the reception state and determining the cell transmission interval based on the information. The data can be transmitted at a different cell transmission rate. As a result, when the traffic of the network becomes small, the data transmission / reception terminal can increase the cell transmission rate and can effectively use the transmission path. Further, when the traffic of the network becomes large, the data transmitting / receiving terminal can reduce the cell transmission rate, and can suppress the cell loss occurring in the network. Furthermore, since the reception state is constantly detected and the cell transmission rate depending on the state is controlled, it is possible to perform communication with high transmission efficiency that follows changes in the state of the network. Further, the present invention is
It can be used for a communication network such as a packet switching network, a cell relay network and a switched multi-megabit data service network that divides data to be transmitted into communication units such as packets or cells and asynchronously transmits the divided data.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a data transmission control system according to an embodiment of the present invention.

FIG. 2 is a graph showing a relational expression of a cell transmission interval with respect to a reception state of the data transmission control method of the present invention.

FIG. 3 is a graph showing a relational expression of a cell transmission interval with respect to a reception state of a data transmission control method according to another embodiment of the present invention.

FIG. 4 is a block diagram of a conventional data transmission control method.

FIG. 5 is a block configuration diagram of another conventional data transmission control method.

[Explanation of symbols]

 10, 10A, 10B data transmission / reception terminal 11 reception state detection type cell transmission rate control device 12 reception state detection unit 20, 20A, 20B cell transmission rate control unit 21 FIFO buffer 22 cell transmission interval adjustment unit 23 cell transmission interval control unit 24A, 24B Cell transmission control unit 25 Counter 26 Token pool 30 ATM network Rmax Maximum number of received cells Rth Number of received cells Threshold Smax Maximum cell transmission interval Smin Minimum cell transmission interval

Claims (2)

[Claims] 1. A data transmission control method for broadcasting data divided into cells of a communication unit via an asynchronous transfer mode network to all valid data transmitting / receiving terminals belonging to the network, wherein each of the data is The transmission / reception terminal has a storage means for temporarily storing data divided into cells, a reception state detection unit for detecting a reception state of the data divided into cells from the asynchronous transfer mode network, and a detection of the reception state detection unit. A cell transmission interval control unit that calculates cell transmission interval information based on the received reception state information, and a cell transmission interval is adjusted by the cell transmission interval information of the cell transmission interval control unit to read the contents of the storage means and perform the asynchronous transfer. A data transmission control method, comprising: a cell transmission interval adjusting unit for transmitting to a mode network. 2. The cell transmission interval control unit stores in advance a relational expression between the number of received cells per unit time received from the asynchronous transfer mode network and a cell transmission interval to be transmitted, and the relational expression and the reception state. The data transmission control system according to claim 1, further comprising means for calculating cell transmission interval information based on the information.