JP2000023139A - Computer-readable recording medium recording communication system and program - Google Patents

Abstract

(57) [Summary] To improve the band efficiency of a transmission path used for data transmission. In a communication system capable of attaching additional data to data and transmitting the data to a terminal via a transmission line, an additional data request signal indicating whether or not to request the additional data is transmitted to the terminal. In the case where the receiving unit 7 accepts from 1 and the additional data request signal received by the receiving unit 7 indicates that the additional data is unnecessary, the bandwidth of the band used for data transmission is excluded from the width of the additional data transmission. Bandwidth determining means 7 for determining a bandwidth, and bandwidth determining means 7
Bandwidth securing means 8 for securing a bandwidth having the bandwidth determined by the transmission line 1 in the transmission path 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a communication system capable of dynamically changing the bandwidth of a transmission line used for data transmission and a computer-readable recording medium on which a program is recorded.

[0002]

2. Description of the Related Art There is a VOD (Video On Demand) system as a communication system for transmitting contents (movies, sports games, news, etc.) composed of video data and audio data from a transmitting device to a receiving terminal.

[0003] In a VOD system, a transmitting side device holding contents and at least one receiving terminal are connected by a transmission path. When a VOD service is started in such a VOD system, an upstream transmission band is secured in a transmission path in order to transmit a request signal from a user (viewer) from a receiving terminal to a transmitting device.

[0004] At the same time, a downlink transmission band is secured in the transmission path in order to transmit the content from the transmitting apparatus to the receiving terminal. Here, the content may be accompanied by additional data related to the content (such as a profile of an actor in a movie, player information of athletes, etc.). Irrespective of whether or not the content is attached, the content with the attached additional data is secured for transmission.

In a general VOD system, when an upstream transmission band and a downstream transmission band are secured (this is called "session is established"), the upstream transmission band and the downstream transmission band are secured during service continuation. Continue to be.

[0006]

As described above, in the conventional communication system, regardless of whether the additional data is attached to the content or not, the bandwidth which can transmit the content to which the additional data is attached can be transmitted. Downstream transmission band.

However, there are cases where the provider providing the VOD service by the transmitting device does not have the additional data to be attached to the content, or the user does not want to supply the additional data.

[0008] In such a case, it is sufficient that a bandwidth sufficient to transmit the content to which no additional data is attached is secured as the downstream transmission band. Therefore, in the conventional communication system, the bandwidth of the downstream transmission band may be needlessly secured, and the band efficiency is reduced.

Also, during execution of the VOD service,
It may be clear that the user does not request, for example, trick play (rewind, fast forward, pause, etc.) or stop content transmission.

[0010] In such a case, the bandwidth of the upstream transmission band may be narrow, but in the conventional communication system, the same bandwidth as in the case where trick play or suspension of content transmission occurs occurs.

Therefore, in the conventional communication system, the bandwidth of the upstream transmission band may be needlessly secured, and the band efficiency is reduced. The present invention has been made in view of the above situation, and has a communication system capable of dynamically changing a data transmission bandwidth according to a data attachment state between a transmitting apparatus and a receiving terminal. And a computer-readable recording medium on which the program is recorded.

[0012]

In order to achieve the above object, the present invention takes the following measures. Claim 1
It is possible to attach additional data to the data, and in a communication system for transmitting data to a terminal via a transmission path, receiving means for receiving from the terminal an additional data request signal indicating whether to request additional data. And determining a bandwidth used for data transmission to be a bandwidth excluding additional data transmission when the additional data request signal received by the receiving unit indicates that additional data is unnecessary. And a band securing unit for securing a band having the bandwidth determined by the bandwidth determining unit in the transmission path.

Therefore, in the communication system according to the first aspect, based on the attached state of the data and the additional data,
Since a band suitable for data transmission can be secured, band efficiency can be improved.

Further, since the bandwidth of the transmission path can be used effectively, the number of receiving sides that can be connected to the transmitting side can be increased. According to a second aspect of the present invention, in the communication system according to the first aspect, when a band is reserved in advance, means for releasing the band once and re-reserving it with a designated width is added.

Therefore, in the communication system of the second aspect, in addition to the same operation and effect as the first aspect, the bandwidth can be freely changed even after the bandwidth is once secured.

Therefore, it is possible to secure an appropriate band according to the current state of the communication service, and it is possible to further improve the efficiency. According to a third aspect of the present invention, in a communication system capable of attaching additional data to data and transmitting the data to a terminal via a transmission path, an additional data request signal indicating whether to request the additional data, Receiving means for receiving, from the terminal, an operation request signal indicating whether or not an operation from the terminal can be performed on the data therein, and indicating that the additional data request signal received by the receiving means does not require additional data. In this case, the bandwidth used for data transmission is determined to be the bandwidth excluding the additional data transmission, and the operation request signal received by the reception unit disables the operation on the data being transmitted. In the case shown, the bandwidth for signal transmission from the terminal is determined by a bandwidth determining unit that determines a bandwidth excluding an operation part for the data being transmitted, and a bandwidth determining unit. The band having a bandwidth with a communication system and a band securing means for securing the transmission path.

Therefore, in the communication system according to the third aspect, in addition to the same operation and effect as in the first aspect, when the operation on the data being transmitted is not received from the terminal, the bandwidth of the operation not transmitted is transmitted. Can be deleted.

According to a fourth aspect of the present invention, an accepting function for accepting, via a transmission path, an additional data request signal indicating whether or not additional data is attached to data and transmitted to the computer, and an accepting function. When the additional data request signal indicates that additional data is unnecessary, a bandwidth determining function for determining a bandwidth used for data transmission to a bandwidth excluding additional data transmission, and a bandwidth determining function. A computer-readable recording medium that records a program for realizing a band securing function for securing a band having the bandwidth determined by the transmission path in the transmission path.

According to a fifth aspect of the present invention, an additional data request signal indicating whether or not to transmit the additional data to the data is received from the terminal via a transmission line, and the computer receives the additional data request signal for the data being transmitted. When an operation request signal indicating whether or not operation from the terminal is enabled is received from the terminal, and the additional data request signal received by the reception function indicates that additional data is unnecessary, the If the bandwidth used for transmission is determined to be the bandwidth excluding the additional data transmission, and the operation request signal received by the reception function indicates that the operation on the data being transmitted is disabled, the terminal Has a bandwidth determining function of determining a bandwidth of a signal transmission band from the mobile terminal to a bandwidth excluding an operation component for data being transmitted, and a bandwidth determined by the bandwidth determining function. A computer-readable recording medium recording a program for implementing a band securing function of securing the transmission path bandwidth.

By using a recording medium on which such a program is recorded, even in the case of an apparatus not having the above-mentioned functions, the above-mentioned functions can be easily added.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, a communication system will be described in which a user (viewer) allocates an appropriate band in a transmission path to each user in response to a request regarding a viewing method.

FIG. 1 is a block diagram showing a configuration of a communication system according to the present embodiment. Here, as an example, a case where the communication system is a VOD system is shown. The receiving terminal 1 is connected to one end of the transmission line 3 via a receiving modem 2, and the transmitting device 4 is connected to the other end of the transmission line 3 via a transmitting modem 5.

The receiving terminal 1 of the VOD system inputs a content selection by the user and transmits the content selection result to the transmitting device 4 as a content selection signal. Further, the user inputs a selection as to whether or not to request the attachment of the additional data to the content, and transmits a selection result regarding the additional data to the transmitting device 4 as an additional data request signal. Further, the user inputs a selection as to whether or not to enable an operation such as a trick play or a suspension of content transmission during the content transmission, and transmits a selection result regarding the operation during the transmission to the transmitting device 4 as a transmission operation request signal. .

On the other hand, based on the content selection signal, the additional data request signal, and the operation request signal during transmission, the transmitting apparatus 4 secures the downstream transmission band 3a and the upstream transmission band 3b having appropriate widths based on the content selection signal, the additional data request signal, and the operation request signal during transmission. And send the content.

The communication system according to the present embodiment will be described below for each component. In the transmitting device 4 of the VOD system, a video server 6, a VOD application server 7, a network control system 8, a charging management server 9, and a multiplexing device 10 are radially connected via a hub 11.

The video server 6 and the multiplexing device 10
Are connected by a dedicated line 12 for transmitting video data and audio data. The video server 6 holds various contents including video data and audio data,
According to the control of the VOD application server 7,
The multiplexing device 10 transmits predetermined contents through the dedicated line 12.
To be transmitted.

The VOD application server 7 holds the additional data relating to the content, and transmits the corresponding additional data to the multiplexer 10 via the hub 11 according to the signal from the receiving terminal 1.

The VOD application server 7
Holds VOD application software (hereinafter, referred to as “VOD application”) 13 executed on the receiving terminal 1.

This VOD application server 7
It has a receiving unit that receives various signals from the receiving terminal 1, and controls other elements of the transmitting device 4 according to the received signals.

That is, the network control system 8
Is the VOD output from the resident application 14 of the receiving terminal 1 that has received the VOD service start request from the user.
The service start request signal is received from the shared transmission band 3c. Then, the network control system 8 secures the downstream transmission band 3a and the upstream transmission band 3b, and notifies the VOD application server 7 of the reservation and a service start request signal.

The VOD application server 7
Receives the service start request signal, and downloads the VOD application 13 to the receiving terminal 1. V
After the download of the OD application 13, the VOD application 13
From the upstream transmission band 3b.

Then, the VOD application server 7
Controls the video server 6, the network control system 8, and the charging management server 9 according to various signals received by the upstream transmission band 3b, and transmits additional data.

Here, the control of the network control system 8 by the VOD application server 7 will be described in detail. VOD application server 7
When the content selection signal from the receiving terminal 1 is received in the shared transmission band 3c, the downlink transmission band to be secured is determined from the state of the additional data request signal and the operation request signal during transmission, which are received in the same manner as the content selection signal. 3a and the width of the upstream transmission band 3b are determined. Table 1 shows an example of the relationship between the downlink transmission band 3a and the additional data request signal received by the VOD application server 7.

[0034]

[Table 1]

The VOD application server 7 determines that the width of the downstream transmission band 3a is 2 Mbps when the additional data request signal indicates that additional data is to be attached to the content, and there is additional data to be attached to the content. .

On the other hand, the VOD application server 7
Determines the width of the downstream transmission band 3a to be 1.5 Mbps when the additional data request signal does not indicate that the additional data is attached to the content. Here, the additional data request signal indicates that the additional data is attached to the content. Even when the additional data related to the content does not exist, the width of the downlink transmission band 3a is similarly set to 1.5 Mbps.
Is determined. Table 2 shows an example of the relationship between the upstream transmission band 3b and the operation request signal during transmission received by the VOD application server 7.

[0037]

[Table 2]

The VOD application server 7 determines the width of the upstream transmission band 3b to be 100 kbps when the operation request signal during transmission requests the operation during content transmission.

On the other hand, the VOD application server 7
Sets the width of the upstream transmission band 3b to 20 kb when the operation request signal during transmission does not request the operation during content transmission.
Determine ps.

Then, the VOD application server 7
Is the downlink transmission band 3 determined according to Tables 1 and 2.
The width of “a” and the width of the upstream transmission band 3 b are notified to the network control system 8.

The network control system 8 secures and manages the downstream transmission band 3a and the upstream transmission band 3b having the width determined by the VOD application server 7. The charging management server 9 manages charging information for the receiving terminal 1 based on the width of the downstream transmission line 3a and the width of the upstream transmission line 3b determined by the VOD application 7. This billing information becomes more expensive as the width of the secured band becomes wider.

The multiplexing device 10 multiplexes video data and audio data received from the video server 6 via the dedicated line 12, and transmits the multiplexed video data and audio data to the receiving terminal 1 via the transmitting modem 5 through the downstream transmission band 3 a of the transmission line 3. Send. When additional data is input in addition to the video data and the audio data, the video data, the audio data, and the additional data are multiplexed and transmitted. The video data and the audio data are often multiplexed and stored in the video server 6.

Further, the multiplexer 10 transmits the VOD application 13 input from the VOD application server 7 to the receiving terminal 1 through the downstream transmission band 3a.

On the other hand, in the receiving terminal 1 of the VOD system, resident application software (hereinafter, referred to as “resident application”) 14 is executed, and the VOD application 13 received by the separating unit 15 is executed.

The content received by the separating unit 15 is separated into video data, audio data, and additional data.
The video data is transmitted from the separation unit 15 to the television device 18 via the video decoder 16 and the screen synthesis unit 17. The audio data is transmitted to the television device 18 via the audio decoder 19. Further, the additional data is processed by the VOD application 13, and the processing result is transmitted to the television device 18 via the screen composition display unit 17.

The resident application 14 is activated when the receiving terminal 1 is activated. Further, the resident application 14 transmits a signal indicating that it has been started to the network control system 8 using the shared transmission band 3c, which is a transmission band shared by a plurality of receiving terminals. In addition,
The shared transmission band 3c is shared with other receiving terminals, but is rarely used, so that the band width is set to be narrow.

That is, the resident application 14
Operates before the session is established, and activates the VOD application 13 downloaded from the VOD application server 7.

The separation unit 15 converts the VO from the downstream transmission band 3a
The D application 13 and content are received. Here, the VOD application 1 received by the separation unit 15
3 starts operation as instructed by the resident application 14 as described above.

The separating section 15 separates the received content into video data and audio data, and transmits them to the video decoder 16 and the audio decoder 19, respectively. Here, when additional data is attached to the received content, the additional data obtained separately is transmitted to the VOD application 13.

The VOD application 13 has a user interface function. That is, the VOD application 13 provides a content selection menu for selecting content to be provided from a plurality of contents. In addition, an additional data menu for selecting whether to request the provision of additional data is provided. Further, a transmission operation selection menu for selecting whether or not to set a mode in which trick play or content transmission stop during content transmission is possible is provided.

These menu screens are transmitted to the television device 18 via the screen synthesizing display unit 17 and displayed as digital video signals that can be displayed on the screen. Also, V
The OD application 13 inputs the selection of the various menus by the user. Then, the content selection signal, the additional data request signal, and the operation request signal during transmission, which are the input results, are transmitted to the transmission device 4 via the reception modem 2, the upstream transmission band 3b, and the transmission modem 5.

Further, the VOD application 13
Converts the additional data received from the separation unit 15 into a digital video signal that can be displayed on the screen, and transmits the digital video signal to the screen synthesis display unit 17.

The audio decoder 19 converts the audio data into a reproducible audio signal and transmits it to the television device 18. The video decoder 16 converts the video data into a displayable analog video signal, and
Send to

The screen synthesizing display section 17 is provided with the video decoder 1
6 and a digital video signal input from the VOD application 13 and transmit the synthesized video signal to the television device 18. When no video signal is input from the VOD application 13,
The video signal input from the video decoder 16 is transmitted to the television device 18 as it is.

The television device 18 includes an audio output device (not shown) for outputting an input audio signal as audio, and a display device (not shown) for displaying the input video signal.

The operation of the communication system having the above configuration will be described below. FIG. 2 shows the VOD application 1 in the communication system according to the present embodiment.
3 is a flowchart showing a process executed until the file No. 3 is downloaded.

First, the user activates the receiving terminal 1, whereby the resident application 14 is activated (s
1). When the operation of the resident application 14 is normal, the resident application 14 and the network control system 8 enter a state where transmission and reception can be performed using the shared transmission band 3c (s2).

Next, a video signal relating to a menu indicating a service that can be provided by the resident application 14 is transmitted to the television apparatus 1 via the screen composition display unit 17.
8 is sent. Thereby, a menu relating to the service is displayed on the television device 18 (s3).

For example, services that can be provided by the receiving terminal 1 include a VOD service and an e-mail display service. Here, it is assumed that the user selects the VOD service (s4).

Then, a signal to start the VOD service is transmitted to the network control system 8 through the shared transmission band 3c (s5). Upon receiving the start signal of the VOD service, the network control system 8 executes the VO service.
A downlink transmission band 3a for downloading the D application 13 is secured. At the same time, an uplink transmission band 3b for transmitting the content selection signal, the additional data request signal, and the operation request signal during transmission is also secured (s
6).

When the session is thus established, the network control system 8 notifies the VOD application server 7 that the securing of the transmission band has been completed (s7).

When the VOD application server 7 is notified of the reservation of the transmission band, the VOD application 13
Is downloaded to the receiving terminal 1 using the downlink transmission band 3a (s8).

Note that the user is not a VOD service,
When the e-mail display service is selected, the e-mail display service is executed (s9). FIG. 3 is a flowchart showing processing executed after the VOD application 13 is downloaded in the communication system according to the present embodiment.

The downloaded VOD application 13 is received by the separating unit 15 and activated by the resident application 14 (t1). Then, by the executed VOD application 13, the video signal of the content selection menu is transmitted to the television device 18 via the screen composition display unit 17 and displayed.
Similarly, the video signals of the additional data menu and the operation selection menu during transmission are transmitted to the television device 18 via the screen composition display unit 17 and displayed (t2).

By referring to the displayed content selection menu, the user selects the content to be viewed, and the result of the selection is input to the VOD application 13. Further, the user selects whether or not to request additional data by referring to the additional data menu, and inputs the selection result. Further, referring to the operation selection menu during transmission, it is selected whether to request an operation such as a trick play or a content transmission stop while viewing the content, and the selection result is input (t3).

In the VOD application 13, a content selection signal, an additional data request signal, and an operation request during transmission are created based on the input from the user for each menu, and these signals are transmitted to the VOID by the upstream transmission band 3b.
D is transmitted to the application server 7 (t4).

In the VOD application server 13,
On the basis of the additional data request signal and Table 1, the downlink transmission band 3
The width of a is determined (t5). Here, the user has requested the attachment of additional data, and when this additional data exists, the width of the downlink transmission band 3a is wide (2M).
bps) (t6).

On the other hand, if no additional data is requested by the user or if there is no corresponding additional data, the width of the downstream transmission band 3a is determined to be a narrow band (1.5 Mbps). (T7).

The VOD application server 13
Thus, the width of the upstream transmission band 3b is determined based on the operation request signal during transmission and Table 2 (t8). Here, when an operation during viewing is requested by the user, the width of the upstream transmission band 3b is determined to be a wide band (100 kbps) (t9).

On the other hand, when the user does not request an operation during viewing, the width of the upstream transmission band 3b is determined to be a narrow band (20 kbps) (t10). In this case, only the VOD service end request signal is handled in the upstream transmission band 3b.

The determined width of the downstream transmission band 3a and the determined width of the upstream transmission band 3b are notified from the VOD application server 7 to the network control system 8. Thereby, the downstream transmission band 3a and the downstream transmission band 3b are secured by the network control system 8 (t1).
1).

The VOD application server 7 requests the video server 6 to distribute the content selected by the user, and the video server 6 transmits video data and audio data to the multiplexer 10 according to the request ( t12).

Further, when the user requests additional data and holds the additional data, (t1
3), the additional data is transmitted from the VOD application server 7 to the multiplexer 10 (t14).

Further, the VOD application server 7
Notifies the charge management server 9 of the user's bandwidth occupancy and the name of the selected content. As a result, the charge according to the occupied bandwidth and the selected content is stored in the charge database provided in the charge management server 9 (t15).

Then, each data input to the multiplexer 10 is multiplexed and transmitted to the receiving terminal 1 using the downlink transmission band 3a (t16). In the receiving terminal 1, the data multiplexed by the demultiplexer 15 is received, and the multiplexed data is demultiplexed by the demultiplexer 15 (t1).
7).

The video data obtained by the separation is transmitted to the video decoder 16 (t18), the audio data is transmitted to the audio decoder 19 (t19), and the additional data and other downlink data are transmitted to the VOD application 13 (t2).
0).

In the VOD application 13,
Processing based on the downlink data is performed. Further, the received additional data is transmitted to the screen composition display unit 17 as a digital video signal (t21).

The video decoder 16 decodes the video data, and converts the analog video signal to the screen composite display unit 1.
7 (t22). In the screen composition display unit 17,
The received video signals are combined and transmitted to the television device 18 (t23).

The audio decoder 19 decodes the audio data, and transmits an analog audio signal to the television device 18 (t24). Television device 1
At 8, the received audio information is output as audio, and the received video signal is displayed on the display device (t2).
5).

At this point, the transmission of the content is terminated, and the user may make a new input to the VOD application 13 with reference to the menu again (t26). When a new input is made by the user, a new content selection signal, a new additional data request signal, and a new operation request signal during transmission are transmitted from the VOD application 13 to the VOD application server 7 (t27).

The VOD application server 7
When receiving various new signals, only a band that does not hinder communication may be re-secured. Then, according to the new signal received by the VOD application server 7, the downstream transmission band 3a and the upstream transmission band 3b
Is determined, and the same processing is repeated thereafter.

As described above, in the communication system according to the present embodiment, when the additional data is not transmitted or when the additional data is not prepared, the downlink transmission bandwidth is lower than when the additional data is transmitted. The width of 3a is reduced.

In the communication device according to the present embodiment, when the user does not request trick play,
Uplink transmission band 3b than when trick play is requested
To reduce the width of.

Therefore, since data transmission can be performed without securing an extra band, band resources of the transmission path 3 can be effectively used. Further, since the bandwidth of the transmission path 3 can be used effectively, the number of receiving terminals 1 connected to the transmitting apparatus 4 can be increased.

Further, when the transmission band is reduced, services such as eliminating charges for the reduced band can be provided. Note that the communication system according to the present embodiment has been described using a VOD system as an example, but the communication system is not limited to this, and various systems that perform communication using a predetermined band of a transmission path may be used. Can be applied.

In the communication system according to the present embodiment, the width of the downlink transmission band is set to 2 Mbps or 1.5 Mbps.
bps, and the width of the upstream transmission bandwidth is 10
It is determined to be 0 kbps or 20 kbps.

However, the present invention is not limited to this, and it is possible to set a bandwidth suitable for the capacity of contents, additional data, and various signals. Further, each function of the communication system according to the present embodiment, as a program that can be executed by a computer,
For example, the present invention can be applied to each device by writing on a recording medium such as a magnetic disk (floppy disk, hard disk, etc.), optical disk (CD-ROM, DVD, etc.), semiconductor memory, or transmitted to a communication medium and applied to various devices. It is possible. A computer that implements the present apparatus reads the program recorded on the recording medium, and executes the above-described processing by controlling the operation of the program.

[0088]

As described above, in the computer-readable recording medium storing the communication system and the program according to the present invention, a user request can be realized when data is transmitted from the transmission side to the reception side. Secure the bandwidth of the transmission path by the level.

Therefore, it is possible to prevent an extra band from being reserved, and to improve the efficiency of the reserved band. In addition, since it is possible to prevent an extra band from being secured, it is possible to increase the number of reception sides that can be connected to the transmission side, thereby reducing the cost of the communication system.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram of a communication system according to the embodiment;
9 is a flowchart illustrating processing executed until an OD application is downloaded.

FIG. 3 is a block diagram of a communication system according to the embodiment;
9 is a flowchart illustrating processing executed after an OD application is downloaded.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Receiving terminal 2 ... Receiving modem 3 ... Transmission path 3a ... Downlink transmission band 3b ... Uplink transmission band 3c ... Shared transmission band 4 ... Transmission side apparatus 5 ... Transmission side modem 6 ... Video server 7 ... VOD application server 8 ... Network Control system 9 ... Charge management server 10 ... Multiplexer 11 ... Hub 12 ... Dedicated line 13 ... VOD application software 14 ... Resident application software 15 ... Separation unit 16 ... Video decoder 17 ... Screen synthesis display unit 18 ... Television device 19 ... Audio decoder

Claims (5)

[Claims] In a communication system capable of attaching additional data to data and transmitting data to a terminal via a transmission path, the additional data request signal indicating whether or not to request the additional data is provided. Receiving means for receiving from the terminal, and when the additional data request signal received by the receiving means indicates that additional data is unnecessary, the bandwidth of the band used for transmitting the data, excluding the additional data transmission A communication system comprising: a bandwidth determining unit that determines a bandwidth; and a band securing unit that secures a band having the bandwidth determined by the bandwidth determining unit in the transmission path. 2. The communication system according to claim 1, further comprising means for, if a band is reserved in advance, releasing the band once and re-securing it with a designated width. system. 3. In a communication system capable of attaching additional data to data and transmitting data to a terminal via a transmission path, an additional data request signal indicating whether to request the additional data, Receiving means for receiving, from the terminal, an operation request signal indicating whether or not the terminal can perform an operation on the data being transmitted; and the additional data request signal received by the receiving means does not require additional data. If the operation request signal accepted by the accepting means determines that the bandwidth of the bandwidth used for data transmission is a bandwidth excluding the additional data transmission, When indicating that the transmission is not possible, a bandwidth determining means for determining the bandwidth of the bandwidth for signal transmission from the terminal to a bandwidth excluding an operation component for the data being transmitted. Communication system, wherein a band having a bandwidth determined by the bandwidth determining means is provided with a band securing means for securing in the transmission path. 4. A receiving function for receiving, via a transmission path, an additional data request signal indicating whether or not additional data is attached to data from a computer, and the additional data received by the receiving function. When the request signal indicates that the additional data is unnecessary, a bandwidth determining function of determining a bandwidth used for transmitting the data to a bandwidth excluding the additional data transmission, and the bandwidth determining function. A computer-readable recording medium storing a program for realizing a band securing function of securing a band having a bandwidth determined by the above-mentioned transmission path in the transmission path. 5. A computer receives, via a transmission path, an additional data request signal indicating whether or not additional data is attached to data and transmitting the data, and controls the terminal to operate the data being transmitted from the terminal. An accepting function for accepting an operation request signal indicating whether or not to enable the accepting function from the terminal; and when the additional data request signal accepted by the accepting function indicates that additional data is unnecessary, transmission of the data is performed. When the bandwidth to be used is determined to be a bandwidth excluding additional data transmission, and the operation request signal received by the reception function indicates that operation on data being transmitted is disabled, the terminal A bandwidth determination function for determining the bandwidth of a band for signal transmission from the bandwidth excluding an operation portion for the data being transmitted, and a bandwidth determined by the bandwidth determination function A computer-readable recording medium storing a program for realizing a band securing function of securing a band having a width in the transmission path.