JPH06284134A - Data transmission control system - Google Patents

Abstract

PURPOSE:To reduce waiting time from production of data to be transmitted till a token is received by devising the system such that a data transmission reception terminal equipment in which data to be sent take place sends a token request signal to a network to request the token. CONSTITUTION:A data transmission reception terminal equipment 1 is provided with a function by which the data transmission reception terminal equipment 1 transmits a token request signal to the network when data to be transmitted are generated and with a function transmitting a token to the data transmission reception terminal equipment 1 making the request signal based on the request signal. In this constitution, the data transmission reception terminal equipment 1 having the token always monitors a signal transmitted from the network and transmits transmission data when the request signal is received and then transmits the token to the data transmission reception terminal equipment 1 transmitting the request signal. Then the data transmission reception terminal equipment 1 sending the request signal sends the data including the token when the token is received.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to transmission by a plurality of data transmission / reception terminals such as a network that shares a transmission medium for transmitting information, an ATM (Asynchronous Transfer Mode) network, a packet switching network, or a frame relay network. It can be used for a communication network in which data to be transmitted is divided into one or a plurality of communication units and transmitted.

The present invention relates to a method of controlling a data transmitting / receiving terminal for performing communication, in which a data transmitting / receiving terminal transmits data on a network performing broadcast communication using a multipoint transmission medium for transmitting information. In this case, it can be used as a method for controlling a data transmission / reception terminal that transmits data to a network.

The present invention is characterized in that a data transmission / reception terminal having data to be transmitted requests a permission signal (token) for permitting data transmission, and the token is transmitted to the data transmission / reception terminal which issued the request. Therefore, the data to be transmitted is divided into one or more communication units such as a network shared by a plurality of data transmitting / receiving terminals, an ATM network, a packet switching network, or a frame relay network. It can be used as a method for controlling a data transmission / reception terminal when performing broadcast communication in a communication network for transmission.

[0004]

2. Description of the Related Art Conventionally, there are a token ring system and a token bus system as a system for determining a data transmitting / receiving terminal for transmitting data to this type of network. First, the token bus system will be described. As shown in FIG.
Is a data transmitting / receiving terminal for transmitting / receiving data, 2 is a bus-like transmission line, 3 is a connecting device for connecting the data transmitting / receiving terminal to the transmission line, and 4 is a terminating device. The token (a signal that permits data transmission) circulates between the data transmitting / receiving terminals in a predetermined order. A data transmission / reception terminal that wants to transmit data becomes in a transmittable state by capturing free tokens (free tokens) that are circulating in a predetermined order. The data transmission / reception terminal that has captured the free token changes the content of the token to the use state (busy token), displays the transmission prohibition of the other data transmission / reception terminal, and then transmits the data. After receiving the response information from the data transmission / reception terminal that has received the data, the data transmission / reception terminal of the transmission source releases the token from the used state to the free state to the transmission path.

Next, the token ring system will be described. As shown in FIG. 2, 5 is a data transmission / reception terminal, and 6 is a transmission line. The data transmission / reception terminal that wants to transmit data waits for a free token to come around, and when the token arrives, converts it into a busy token and transmits the data (frame) to which transmission data and the like are added. When the head of the transmitted frame makes a round and returns to the data transmitting / receiving terminal that has transmitted the data, the data transmitting / receiving terminal that has transmitted the data transmits a new free token and simultaneously removes the returning frame from the transmission path.

In the conventional token bus system and token ring system, since the tokens are circulated in a predetermined order, the time from the sending of a free token to the acquisition of the next free token (token wait time)
is necessary. For this reason, in the data transmission / reception terminal in which the data to be transmitted has occurred, even if the other data transmission / reception terminal does not have the data to be transmitted, the data cannot be transmitted until the free token circulates. Therefore, although there is a data transmitting / receiving terminal having data to be transmitted, no data transmitting / receiving terminal transmits data, and there is a wasteful time of waiting for a free token to circulate. was there. Furthermore, this wasted time increases as the number of data transmitting / receiving terminals in which free tokens circulate increases.

[0007]

Therefore, in order to solve the above-mentioned problems of the conventional example, the present invention transmits a signal requesting a token (request signal) to a network by a data transmitting / receiving terminal in which data to be transmitted has occurred. By requesting a token by using the token, it is intended to reduce the token waiting time from the generation of data to be transmitted in the data transmission / reception terminal to the reception of the token.

[0008]

According to the present invention, in a data transmitting / receiving terminal, when a data to be transmitted is generated, the data transmitting / receiving terminal transmits a signal requesting a token (request signal) to a network, and the request signal thereof. In response to the request signal, a function of transmitting a token to the data transmitting / receiving terminal (token allocation function) is provided.

When data to be transmitted is generated in the data transmitting / receiving terminal, a signal requesting a token (request signal) is transmitted to the network. The data transmission / reception terminal that owns the token constantly monitors the signal sent from the network, and when it receives the request signal, it transmits the transmission data and then sends the token to the data transmission / reception terminal that transmitted the request signal. To do. Upon receiving the token, the data transmission / reception terminal that has transmitted the request signal transmits the data possessing the token.

In a data transmission / reception terminal having a token, if the request signal is not received while transmitting the data, the token is held even after the data is transmitted until the request signal is received. When the request signal is received, the token is transmitted to the data transmitting / receiving terminal that transmitted the request signal.

When a plurality of data transmission / reception terminals transmit request signals, the data transmission / reception terminal possessing the token determines the request signal to be valid according to a predetermined algorithm, such as validating the request signal received first. Then, the token is transmitted to the data transmitting / receiving terminal that has transmitted the valid request signal. At this time, the data transmission / reception terminal that has transmitted the invalidated request signal will receive the token addressed to the other data transmission / reception terminal, and therefore will transmit the request signal again when the token addressed to the other data transmission / reception terminal is received. To do.

When the data transmission / reception terminal detects a loss of the request signal, or when the token addressed to the own data transmission / reception terminal or the other data transmission / reception terminal is not received for a certain period of time, the data transmission / reception terminal which transmitted the request signal Recognizes that the transmitted request signal is lost and retransmits the request signal.

[0013]

In the data transmitting / receiving terminal, the request signal is transmitted at the time when the data to be transmitted is generated, and the device having the token allocation function sends the token to the data transmitting / receiving terminal which has issued the request signal in response to the request signal. By transmitting the data, the data transmission / reception terminal possessing the data to be transmitted can reduce the waiting time from the occurrence of the data until the possession of the token.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. FIG. 3 shows a flow chart of an embodiment of the data transmission control method of the data transmitting / receiving terminal. When data to be transmitted occurs at the data transmission / reception terminal (YES in 7)
Then, a signal requesting the token (request signal) is transmitted to the network (8). Then, when the token cannot be received even after a certain period of time (YES in 10), the request signal is recognized as being lost, and the request signal is transmitted again to the network (8).

When the data transmission / reception terminal which has transmitted the request signal receives the token (9), it is identified whether the destination of the token is its own terminal (11). At this time, when the destination of the token is the other end (NO in 11), the request signal is transmitted again to the network (8). When the destination of the token is the own terminal (YES in 11), possessing the token and starting transmission of data to the network (1
2).

The data transmission / reception terminal possessing the token is
It constantly monitors the signals sent from the network, and when it receives the request signal (YES in 13), if the data to be transmitted still exists, the terminal that has transmitted the request signal will terminate the data transmission. A token is sent to the destination (14). Further, in the data transmitting / receiving terminal having the token, if the data to be transmitted is generated before receiving the request signal (YES in 15), the transmission of the data to the network is started (12).

When the data transmission / reception terminal possessing the token receives a plurality of request signals while possessing the token (13), the request signal received first is validated and the subsequent request signals are transmitted. The token is invalidated and the token is transmitted to the data transmission / reception terminal that transmitted the request signal received first (14). When the data transmission / reception terminal that transmitted the request signal receives a token addressed to another data transmission / reception terminal (NO in 11), recognizes that the request signal transmitted by the self terminal has become invalid and transmits the request signal again. Yes (8).

In the embodiment of FIG. 3, when the data transmission / reception terminal possessing the token receives a plurality of request signals while possessing the token, in addition to the system of FIG. 3, the system shown in the flowchart of FIG. It is also possible to determine the request signal to be valid by. This is also an example in which the loss of the request signal is detected instead of the case of recognizing the loss of the request signal by the lapse of time while the token is not received.

The operation of the system of FIG. 4 will be described. When data to be transmitted is generated in the data transmission / reception terminal (YES in 16), a signal requesting a token (request signal) is transmitted to the network (17). When the loss of the request signal is detected (YES in 18), the request signal is transmitted again to the network (17).

When the data transmitting / receiving terminal that has transmitted the request signal receives the token (19), it identifies whether the destination of the token is its own terminal (20). At this time, when the destination of the token is another terminal (NO in 20), the request count value is incremented by 1 (21), and the request signal in which the request count is written is transmitted to the network (17). When the destination of the token is the own terminal (YES in 20), possession of the token and disclosure of data transmission to the network (22).

The data transmission / reception terminal possessing the token is
When the signal sent from the network is constantly monitored and the request signal is received (YES in 23), if the data to be transmitted still exists, the terminal that has transmitted the request signal will terminate the data transmission. A token is sent to the destination (25). In addition, in the data transmission / reception terminal possessing the token, when data to be transmitted occurs before receiving the request signal (YES in 24), the transmission of the data to the network is started (22).

When a plurality of request signals are received at the data transmitting / receiving terminal having the token while carrying the token (23), the data transmitting / receiving terminal having the token requests the request written in each received request signal. The value of the number of times is monitored, and the request signal with the maximum number of requests is made valid, and the other request signals are made invalid. After the data transmission is completed, the token is transmitted to the data transmitting / receiving terminal which has transmitted the valid request signal (25).

The embodiments of FIGS. 3 and 4 are examples in which all the data transmitting / receiving terminals connected to the network are provided with a function of transmitting a token (token allocation function) to the data transmitting / receiving terminal which has transmitted the request signal. However, the token allocation function may be provided in a device such as a node, one specific data transmitting / receiving terminal, or one specific node. In this case, the data transmission / reception terminal having the token transmits the transmission data, then transmits the token to the device having the token allocation function, and transmits the request signal in the device having the token allocation function. Send a token to.

[0024]

As described above, according to the present invention, when a data to be transmitted is generated, a signal requesting a token is transmitted, and a data transmitting / receiving terminal possessing a token corresponding to the signal requests the token. By transmitting the token to the data transmission / reception terminal that issued the request, it is possible to reduce the waiting time from the generation of the data to be transmitted until the possession of the token. From this, despite the existence of the data transmitting / receiving terminal having the data to be transmitted,
It is possible to reduce the wasteful time of waiting for a token to circulate without transmitting data by any data transmitting / receiving terminal.

[Brief description of drawings]

FIG. 1 is a block diagram of a token bus system.

FIG. 2 is a configuration diagram of a token ring system.

FIG. 3 is a flowchart of an embodiment of a data transmission control system of the present invention.

FIG. 4 is a flowchart of another embodiment of the data transmission control system of the present invention.

[Explanation of symbols]

 1 data transmission / reception terminal 2 bus-shaped transmission line 3 connection device 4 termination device 5 data transmission / reception terminal 6 ring-shaped transmission line 7 to 25 program steps

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 8529-5K H04L 11/20 102 A

Claims (1)

[Claims] 1. In a network that broadcasts information to a data transmission / reception terminal that divides transmission data into one or a plurality of communication units and transmits, when data to be transmitted occurs in the data transmission / reception terminal,
Means for transmitting a request signal requesting permission for data transmission,
Means for identifying the destination of the authorization signal that permits data transmission,
A means for recognizing the source of the request signal, a means for transmitting a permission signal to the source of the request signal, a means for identifying whether the information from the network is a permission signal, a request signal, or data, recognizing that the request signal has been lost , A means for retransmitting the request signal, a means for recognizing that the destination of the permission signal is not the data transmitting / receiving terminal and retransmitting the request signal, and the data transmitting / receiving terminal generates data to be transmitted, the request signal When the data transmitting / receiving terminal that has transmitted the request signal receives the request signal, the data transmitting / receiving terminal that transmits the request signal transmits the permission signal to the sender of the request signal, and the data transmitting / receiving terminal that transmits the request signal receives the data A data transmission control method characterized by: