JPH0662026A - Data transmission method and system in token ring type network - Google Patents

Abstract

PURPOSE:To transmit real time data in a network system constituted of a token ring type network and information terminal equipments connected to the network. CONSTITUTION:In the token ring type network system for which plural information terminals 7 are connected respectively through information processors 3 to a ring-like transmission line 1, data read out of a buffer device 5 is controlled by a timer 4 so as to transmit data below a fixed amount by a fixed cycle by the information processor 3 for transmitting the real time data such as video images and sound, etc., among the information terminals. Thus, by transmitting/receiving the real time data mutually among the plural terminals, conversion and a conference can be performed without unnaturalness using the video images and the sound when constituting a conference system or the like by the token ring type network.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and system for transmitting data in a token ring network, more specifically, a plurality of communication terminals are connected by a ring-shaped transmission line, and each information terminal uses the transmission line by means of a token. The present invention relates to a data transmission method and system for transmitting data, particularly real-time data such as video and audio as data while securing the right.

[0002]

2. Description of the Related Art Token ring type networks have already been standardized by IEEE 80
There are 2.5 Token Ring and FDDI which are being standardized in ANSI X3T9.5. These networks are used for data transmission between terminal devices such as personal computers and workstations where data to be transmitted does not require real-time processing.

Recently, it has been considered to transmit real-time data such as video and audio through a token ring type network. Regarding real-time data transmission, the one using FDDI has been proposed by Daido, Sezaki, Yasuda, et al., Institute of Industrial Science, University of Tokyo. (The Institute of Electronics, Information and Communication Engineers:
SSE91-138) However, the above proposal is FDD
It uses the priority function of the I standard,
Since the priority function is not implemented in the actual product, this proposed method cannot be used in practice.

[0004]

Problems that arise when transmitting video and audio data using a token ring network are changes in delay time and large delay times. Even if the delay time is large, if the value is constant, the video and audio can be sent without disturbance, but if the delay time changes, the video may stop or the audio may be interrupted. In addition, in a dialogue using transmission of video and audio, if the delay time of video and audio increases, the response from the other party will also be delayed accordingly, making it impossible to conduct a natural dialogue.

In data transmission in a token ring type network, only an information terminal having a token can transmit data among a plurality of information terminals connected to the network. Therefore, the time during which data can be transmitted after a data transmission request is generated at an information terminal increases the delay time in data transmission. Also, the delay time is not constant because it is not possible to predict in advance when the data can be transmitted, that is, the time when the token is obtained. As described above, it is impossible to send real-time data such as video and audio as they are in the conventional token ring network. Therefore, an object of the present invention is to realize a data transmission method and system capable of transmitting real-time data such as video and audio in a token ring network.

[0006]

In order to achieve the above object, in a data transmission method in a token ring network of the present invention, a plurality of information terminals are respectively coupled to a ring-shaped transmission line through an information processing device, and a plurality of information terminals are connected. In data transmission in a token ring network in which one of the information terminals obtains a transmission right and transmits data, when the information of the information terminal is real-time data, the information processing device makes the real-time data constant at a constant cycle. The data is controlled to be transmitted by dividing the data into a data amount less than or equal to the transmittable data amount.

In the above-mentioned fixed period, one information processing device transmits once based on the transmission capacity of the network, the number of information processing devices connected to the network, and the maximum delay time required by the system in the transmission of real-time data. The amount of data that can be transmitted is set in the information processing device in advance or is calculated and determined by the program by the information processing device.

[0008]

According to the above-described data transmission method of the present invention, the time required for all information processing devices transmitting real-time data to complete one data transmission and start the next data transmission is
It is constant, does not exceed the maximum delay time, and the data reception corresponding to the data transmission is completed before the next data transmission, so that the data is received after a certain information processing device transmits the data. Delay time does not exceed the maximum required delay time. Thus, by setting the maximum delay time to a value at which humans do not feel unnatural due to delay, it is possible to construct a natural dialogue system or the like using a network.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a network block diagram for explaining an embodiment of a data transmission method in a token ring network according to the present invention. In the figure, 1 is a ring-shaped transmission line. At the point A, the information terminal 7 is connected to the network 1 via the information processing device 3 and the network interface 2. The information processing device 3 and the network interface 2 transmit data to the network 1 and receive data from the network 1. The network interface 2 also sends and receives tokens. The information processing device 3 stores an input / output management device 6 that manages input / output of transmission data from the information terminal 7 and reception data from the network interface 2 and transmission data from the input / output management device 6, and controls the network. A buffer device 5 for outputting to the interface 2 and a timer for setting a data transmission interval time, and sending a signal to the buffer device 5 at regular intervals to determine a data output time interval from the buffer device 5 to the network interface 2 Holds 4. Although not shown in the figure, the information processing device 3 includes a processor that controls the output time interval of the timer. Similar devices are provided at the other points B and C, respectively, and the same devices as described above are denoted by the same reference numerals as those given to the respective devices at the point A. Although FIG. 1 shows the case of three points A, B and C for simplification of description, the number of points may be three or more.

The operation of this embodiment will be described below. Prior to the transmission of the real-time data, the information processing device 3 transmits the real-time data by the number n of the information processing devices 3, the transmission capacity T (bit / sec) of the network 1, and the information processing device 3.
One cycle ct of data transmission of the buffer device 5 from the bit rate b (bit / sec) required for transmission of real-time data per device and the maximum delay time tmax (sec) allowable for transmission of real-time data. Determines the amount of data d that can be transmitted to. The information processing device 3 includes a processing program for determining the data amount d, and when the configuration of the token ring network is determined, the number n and the transmission capacity T
The value of is set in the memory of the information processing device 3. When the number n of information processing devices 3 connected by the transmission line 1 is changed, the value of n is updated accordingly. The determined data transmission time interval ct is set in the timer 4, and the value of the data amount d that can be transmitted at one time is set in the buffer device 5.

When the data transmitted from the information terminal 7 is input to the input / output management device 6, the input / output management device 6 outputs the data to the buffer device 5. The buffer device 5 stores the data from the input / output management device 6. Then, the data of the data amount d set by the signal from the timer 4 is output to the network interface 2. The network interface 2 transmits the data from the buffer device 5 to the network 1 and outputs the data received from the network 1 to the input / output management device 6. The input / output management device 6 puts the received data from the network interface 2 into the information terminal 7.

FIG. 2 is a time chart showing the data transmission in the above embodiment. In the figure, the horizontal axis represents time and the vertical axis represents points A, B, and C. In this embodiment, each of the points A, B, and C in the conference system is
The case where the broadcast communication is performed mutually is shown.

Real-time data at points A, B, and C are represented by Da,
Db and Dc, and the bit rates are equal (for example, 64 Kbits of voice) b (bit / sec).

At the time point t1, the point A obtains a token and sends out the real-time data Da1 at the point A in the period ct before the time point t1 to the transmission line as the data A1 at the bit rate T (bit / sec). Data A1 is received at points B and C at times t2 and t3, respectively. Data A1 at time t4
Returns to point A, so the token is released at point A.

When the token is released, the point B obtains the token and sends the real-time data Db1 at the point B in the period ct before the time t5 to the transmission line as the data B1 at the bit rate T (bit / sec). Data B1 is received at points C and A at times t6 and t7, respectively. Time point t8
Then, since the data B1 returns to the point B, the token is released at the point B.

When the token is released at point B, point C
Obtains the token and sets the real time data Dc1 at the point C in the period ct before the time t9 to the bit rate T (bit / sec)
Then, the data C1 is sent to the transmission line. Data C1 is received at points A and B at times t10 and t11, respectively. At time t12, the data C1 returns to the point B, so the token is released at the point C. At time t13, the point A obtains a token and repeats the above operation.

In order to realize the above transmission, b × n <
At T 1, the maximum value of the cycle ct is shorter than tmax. Also, the amount of data d transmitted by one point in one cycle ct is d
= B × ct. The above description has described the case where the points A, B, and C simultaneously perform the same law communication, but the same applies when the points are not the same law communication. It may also be the case that only a specific point transmits. This enables real-time data transmission that does not exceed the set maximum delay time tmax.

FIG. 3 is a block diagram showing the configuration of the information processing apparatus 3 used in another embodiment of the data transmission method in the token ring network according to the present invention.
In this embodiment, real-time data and non-real-time data are transmitted. In the figure, 9 is a real-time data buffer that stores only real-time data, and 10 is a non-real-time data buffer that stores only non-real-time data. Reference numeral 11 designates the data transmission time from the signal from the timer 4 in which the amount of data that can be transmitted at one time is set, reads the data from the real-time data buffer 9 at the time of data transmission, and the amount is 1
The data transmission control device transmits the difference from the non-real-time data buffer 10 to the network interface 2 when the amount of data is less than the amount of data that can be transmitted at one time.

The real-time data terminal 7 and the non-real-time data terminal 8 are connected to the input / output management device 6, and the input / output management device 6
Determines whether the data from the terminals 7 and 8 is real-time data or non-real-time data, stores the data from the real-time data terminal 7 in the real-time data buffer 9, and stores the data from the non-real-time data terminal 8. If so, real-time data buffer 10
To store. The data transmission control device 11 reads data from the real-time data buffer 9 in response to a signal from the timer 4 and outputs the data to the network interface 2 to perform one transmission in which the data amount read from the real-time data buffer 9 is set. When the available data amount is less than the available data amount, the difference between the transmittable data amount and the data amount read and output from the real-time data buffer 9 is read from the non-real-time data buffer 10 and the network interface 2
Output to. According to this embodiment, it is possible to mix real-time data and non-real-time data, and data that does not require real-time data can be transmitted, so that the network can be effectively used.

FIG. 4 is a diagram for explaining a method of transmitting data that exceeds the transmittable data amount that occurs when the transmission real-time data amount in the embodiment shown in FIG. 3 changes with time. FIG. 4A is a diagram modeling the generation amount of data sent from the input / output management device 6 to the real-time data buffer 9. From the input / output management device 6, D0, D in the figure
1, D2, ..., D9 are sequentially sent to the real-time data buffer 9. This figure shows the amount of data sent from the input / output management device 6 to the real-time data buffer 9 from one data transmission to the next data transmission, and D2 and D3 exceed the transmittable data amount. It indicates that the amount of data. If such data from the input / output management device 6 is transmitted to the network 1 as it is, it will interfere with the transmission of real-time data at other points. Therefore, the data transmission control device 11 transmits the data without interfering with the real-time data transmission at other points by sending the transmittable data amounts as shown in FIG. 4B. However, for this method to be effective, it is necessary that the real-time data sent per unit time does not exceed the amount of data that can be sent per unit time.

FIG. 5 is a block diagram showing the configuration of a network system used in still another embodiment of the data transmission method in the token ring network according to the present invention. 12 is a ring-shaped transmission line for an FDDI network which is a token ring network, and 13 is an FD
An FDDI interface for the DI network 12, 16 compresses video data to generate variable-length or fixed-length data in a constant cycle or indefinite cycle, notifies data generation by an interrupt signal, receives compressed video data, and converts it into video. Decompressing video CODEC, 17 is a voice CODEC for converting voice into data and notifying the generation of data by an interrupt signal, or receiving voice data and converting the voice into voice, 19 is FDD
A hard disk for recording data that needs to be transmitted / received via the I network 12, and 15 for storing data to be transmitted. The real-time data buffer 9 and the non-real-time data buffer 10 shown in FIG. A memory having a function of, 14 is a data transmission control device 11 and a timer 4
And a CPU having the functions of the input / output management device 6, 18 is a CPU
Reference numeral 14 is a VME bus for exchanging data with the FDDI interface 13, the memory 15, the video CODEC 16 and the audio CODEC 17. Although only three points A, B and C are shown in the embodiment of FIG. 5, the number of points may be more than that, and the configuration of points B and C, the operation is the configuration of point A, The operation is the same.

The operation of this embodiment shown in FIG. 5 will be described below. When data is generated in the video CODEC 16 or the audio CODEC 17, the CPU 14 is notified of the data generation by an interrupt signal, and the CPU 14 is
Video data from 16 and audio data from the audio CODEC 17 are read via the VME bus and recorded in the memory 15 as real-time data. The data from the hard disk 19 is also read into the memory 15 via the CPU 14. At that time, video CODEC 16 and audio CODEC 17
The data from the hard disk 19 is classified and recorded. The CPU 14 is preset with a data transmission cycle and the amount of data that can be transmitted at that time.
The data less than or equal to the transmittable data amount set in the cycle set to 4 is read from the memory 15 and output to the FDDI interface 13.

When transmitting the real-time data, the audio data is first output, and then the video data is output. This allows
Specific real-time data can be sent with priority. When all the real-time data to be transmitted is less than the transmittable data amount, the difference is used for non-real-time data transmission.
As a result, even in this embodiment, real-time data and non-real-time data can be transmitted. The FDDI interface 13 sends the data received from the CPU 14 to the FDDI network 12.

The CPU 14 is preset with a data transmission cycle and the amount of data that can be transmitted at that time. The value depends on the number of points n for transmitting real-time data and the transmission capacity T of the FDDI network 12. Bit rate b (bit / se) required for transmitting real-time data per unit
c) and the maximum delay time tma in the transmission of real-time data
The transmission cycle ct of data recorded in the memory 15 from x (sec) and the data amount d that can be transmitted at one time are the same as those described in FIG.

[0025]

As described above, according to the present invention, real-time data can be transmitted on a token ring network, and real-time data such as video and audio can be transmitted on the network. You can easily build an application using.

Further, since it is possible to mix real-time data and non-real-time data, it is possible to construct an application using real-time data without changing the existing application.

[Brief description of drawings]

FIG. 1 is a network configuration diagram illustrating an embodiment of a data transmission method in a token ring network according to the present invention.

FIG. 2 is a time chart diagram illustrating a data amount d that can be transmitted in one cycle ct of data transmission in the above embodiment.

FIG. 3 is a block diagram showing a configuration of an information processing device 3 used in another embodiment of the data transmission method in the token ring network according to the present invention.

FIG. 4 is a diagram illustrating a method of transmitting data that exceeds the transmittable data amount that occurs when the real-time transmission data amount changes with time in the embodiment shown in FIG.

FIG. 5 is a block diagram showing a configuration of a network system used in still another embodiment of the data transmission method in the token ring network according to the present invention.

[Simple explanation of symbols]

1: Network 2: Network interface 3: Information management device 4: Timer 5: Buffer device 6: Input / output management device 7, 8: Information terminal 11: Data transmission control device 12: FDDI network 13: FDDI
Interface 14: CPU 15: Memory 16: Video CODEC 17: Audio CO
DEC 18; VME Bus 19: Hard Disk

Claims (8)

[Claims] 1. A data transmission method in a token ring network in which a plurality of information terminals are respectively coupled to a ring-shaped transmission line via an information processing device, and one of the plurality of information terminals obtains a transmission right to transmit data. In the information processing apparatus, when the data is real-time data, the real-time data is controlled so as to be divided into data having a certain transmittable data amount or less at a constant cycle for transmission. Data transmission method. 2. The data transmission method according to claim 1, wherein when the real-time data amount in the transmission period of the fixed cycle is smaller than the transmittable data amount, the difference between the transmittable data amount and the real-time data amount. Is used for transmission of data other than real-time data. 3. The data transmission method according to claim 1, wherein the amount of real-time data to be transmitted varies with time, and the amount of real-time data in the transmission period of the fixed cycle at the time of transmission is the transmittable data. A data transmission method in which, when the amount is exceeded, the amount of data exceeded by the information processing device is transmitted in the transmission period after the next time. 4. The data transmission method according to claim 1, wherein a plurality of types of transmission data including real-time data are managed and controlled in an information processing device that performs transmission, thereby transmitting a plurality of types of data including real-time data. Data transmission method for transmission. 5. The data transmission method according to claim 4, wherein specific real-time data among a plurality of types of transmission data is transmitted with priority over other transmission data. 6. A data transmission system in a token ring network in which a plurality of information terminals are respectively coupled to a ring-shaped transmission line via an information processing device, and one of the plurality of information terminals obtains a transmission right to transmit data. The information processing apparatus divides the real-time data into data having a certain transmittable data amount or less at a constant cycle when the buffer device for transmitting data and the data stored in the buffer device are real-time data. A data transmission system comprising a timer for transmitting to the transmission line, an information terminal, the buffer device, and an input / output management device for managing exchange of the data. 7. A data transmission system in a token ring network in which information terminals at a plurality of points are respectively coupled to a ring-shaped transmission line through an information processing device, and one of the plurality of information terminals obtains a transmission right to transmit data. The information terminals at some of the plurality of points have a real-time data terminal and a non-real-time data terminal, and the information processing apparatus has a first buffer device for real-time data transmission and a non-real-time data transmission Second buffer device, a timer for reading the data stored in the first buffer device by dividing it into data of a fixed transmittable data amount or less at a constant cycle, and the first buffer device driven by the timer. When the real-time data read from is less than or equal to the fixed transmittable data amount, the difference between the read real-time data and the transmittable data amount Managing data transmission / reception between the first and second buffer devices, and the data transmission control device for transmitting the minute data amount from the second buffer device to the transmission path, the real-time data terminal and the non-real-time data terminal And a data input / output management device for controlling the data transmission system. 8. A data transmission system in a token ring network in which a plurality of information terminals are respectively coupled to a ring-shaped transmission line through an information processing device, and one of the plurality of information terminals obtains a transmission right to transmit data. The information processing apparatus includes a network interface connecting the ring-shaped transmission line and a VME bus, and the VME.
A video CODEC connecting the bus, an audio CODEC connecting the VME bus, video data from the video CODEC and audio data from the audio CODEC are read through the VME bus, and are read as real-time data. C, which stores the data in a memory in advance, and outputs in advance a period of data transmission and a data amount less than the amount of data that can be transmitted at that time from the memory to the network interface.
A data transmission system comprising a PU.