JP2009033482A - Data transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technology for solving the problem that one communication occupies a band when a plurality of communications share the band. <P>SOLUTION: Facsimile equipment 1 performs batch broadcast by Direct SMTP communication to the other facsimile equipment. Here, the limited number of sessions determining an upper limit value of the number of sessions to which the facsimile equipment 1 is simultaneously connected is set in a session limited number setting part 13. In addition, a TOS value determining priority between the batch broadcast and other communication in which the band is competed with the batch broadcast is set in a TOS value setting part 14. The session limited number setting part 13 limits that the batch broadcast occupies the band based on the limited number of sessions. In addition, a router which inputs pieces of transmission data by the batch broadcast and other communication together limits that the batch broadcast occupies the band based on the TOS value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for solving the problem that one communication occupies a band when a plurality of communications share the band.

  A data transmitting apparatus may transmit data to a plurality of data receiving apparatuses. There are roughly two types of methods for transmitting data by the data transmitting apparatus. First, there is a method in which a data transmission apparatus starts transmitting data to another data receiving apparatus after the data transmission apparatus finishes transmitting data to one data receiving apparatus (sequential broadcast). Next, there is a method in which the data transmission device transmits data to a plurality of data reception devices at the same time (simultaneous broadcast).

  When a data transmission device transmits data via an SMTP (Simple Mail Transfer Protocol) server and a POP (Post Office Protocol) server, it is possible to perform simultaneous broadcasting to a plurality of data reception devices. However, a plurality of data receiving apparatuses need to make a data distribution request to the POP server. Therefore, real-time data transmission / reception cannot be realized.

  There is a method in which a data transmission apparatus transmits data without going through an SMTP server and a POP server (Direct SMTP transmission). In the direct SMTP transmission, the plurality of data receiving devices do not need to make a data distribution request to the POP server. Therefore, real-time data transmission / reception can be realized.

JP 2003-110624 A

  In direct SMTP transmission, the data transmission apparatus needs to individually connect a plurality of data reception apparatuses to each other. When the data transmitting apparatus sequentially broadcasts to a plurality of data receiving apparatuses, the number of session connections by the data transmitting apparatus is one. However, when the number of data receiving devices is large, sequential broadcasting requires time.

  When the data transmitting apparatus broadcasts simultaneously to a plurality of data receiving apparatuses, the number of session connections by the data transmitting apparatus is equal to the number of data receiving apparatuses. Therefore, even when the number of data receiving devices is large, simultaneous broadcasting does not require time. However, when a plurality of communications share a band, since simultaneous broadcast occupies the band, other communications cannot be performed smoothly.

  In Patent Document 1, the data transmission device can perform simultaneous broadcasts to a plurality of data reception devices based on the number of data that the data transmission device can simultaneously broadcast and the number of sessions to which the data reception device can simultaneously connect. . However, the data transmission device does not limit the number of data and the number of sessions in consideration of other communications. For this reason, when a plurality of communications share a band, the problem that the simultaneous broadcast occupies the band cannot be solved.

  In view of the above problems, an object of the present invention is to provide a technique for solving the problem that one communication occupies a band when a plurality of communications share the band.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a data transmission device, wherein a transmission unit that performs simultaneous broadcasting to a plurality of destinations, and an upper limit value of the number of sessions to which the transmission unit is connected simultaneously, And a session limit number setting unit for setting the limit number.

  The invention according to claim 2 is the data transmission device according to claim 1, wherein the session limit number setting unit reduces the session limit number when the transmission unit requires bandwidth control, It is characterized by including.

  The invention according to claim 3 is the data transmission device according to claim 1 or 2, wherein the session limit number setting unit sets the session limit number when the transmission unit does not require bandwidth control. Means for increasing.

  The invention according to claim 4 is the data transmission device according to any one of claims 1 to 3, wherein the simultaneous broadcast has priority over the communication in which the broadcast and the bandwidth compete. A priority setting unit that sets a priority that defines whether or not to be performed.

  The data transmitting apparatus according to the present invention limits the number of sessions connected simultaneously when performing simultaneous broadcasting to a plurality of data receiving apparatuses. Further, when it is determined that the bandwidth control is necessary, the data transmitting apparatus reduces the number of sessions connected simultaneously. Further, when the data transmitting apparatus determines that the bandwidth control is not necessary, the data transmitting apparatus increases the number of sessions connected simultaneously.

  The data transmission apparatus according to the present invention increases or decreases the number of sessions to be simultaneously connected in consideration of other communications. Therefore, when multiple communications share a bandwidth, the problem of simultaneous broadcast occupying the bandwidth can be solved.

{Fax transmission / reception system}
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of a fax transmission / reception system. The fax transmission / reception system includes fax machines 100 to 132, an IP (Internet Protocol) telephone 2, a router 3, the Internet 4, a DNS (Domain Name System) server 5, a DHCP (Dynamic Host Configuration Protocol) server 6 and the like. .

  The fax machine 100 performs simultaneous broadcasting to 32 fax machines 101 to 132. Broadcasting is performed via the router 3 and the Internet 4, but not via the SMTP server and the POP server. In other words, simultaneous broadcast is performed by Direct SMTP transmission. IP telephone 2 performs IP telephone communication with another IP telephone (not shown). IP telephone communication is also performed via the router 3 and the Internet 4. In other words, simultaneous broadcast and IP telephone communication are communication in which bandwidths compete in the router 3.

  The fax machine 100 performs simultaneous broadcasting upon receiving the IP address settings of the fax machines 101 to 132. Alternatively, the fax machine 100 receives the settings of the host names and domain names of the fax machines 101 to 132, calculates the IP address from the host name and domain name using the DNS server 5, and performs simultaneous broadcast. When the DHCP server 6 dynamically allocates IP addresses to the fax machines 101 to 132, the DNS server 5 only needs to be able to cope with the dynamic allocation of IP addresses.

  FIG. 2 is a block diagram showing components of the fax machine 1. The fax machines 100 to 132 basically include the components of the fax machine 1. The fax machine 100 uses components for transmitting data among the components of the fax machine 1. The fax machines 101 to 132 use components for receiving data among the components of the fax machine 1.

  The fax machine 1 includes a destination setting unit 11, a data input unit 12, a session limit number setting unit 13, a TOS (Type Of Service) value setting unit 14, a data output unit 15, a transmission unit 16, a reception unit 17, and the like. .

  The destination setting unit 11 is a functional unit for the user to set a destination. The data input unit 12 is a functional unit for a user to input transmission data. Examples of the data input unit 12 include a scanner for inputting transmission data, an input interface for inputting transmission data from a user terminal, and the like. The transmission unit 16 transmits the data input by the user using the data input unit 12 to the destination set by the user using the destination setting unit 11.

  The receiving unit 17 receives data. The data output unit 15 is a functional unit for outputting received data. Examples of the data output unit 15 include a printer that prints received data, an output interface that outputs received data to a user terminal, and the like.

  The session limit number setting unit 13 sets the upper limit number of sessions to which the fax machine 1 is connected simultaneously as the session limit number. For example, when the session limit number is 8, the fax machine 1 can simultaneously connect sessions to eight other fax machines. In addition, the session limit number setting unit 13 increases or decreases the session limit number according to the status of other communications in which the broadcast and the bandwidth compete.

  The TOS value setting unit 14 sets a TOS value that prescribes which of the simultaneous broadcast and other communication in which the bandwidth conflicts with the simultaneous broadcast should be preferentially performed. For example, when the TOS value of the simultaneous broadcast is smaller than the TOS value of other communication whose bandwidth competes with the simultaneous broadcast, the other communication with the bandwidth competing with the bandwidth is prioritized over the simultaneous broadcast. The transmission unit 16 writes the TOS value set by the TOS value setting unit 14 in the IP header related to the transmission data.

{Transmission preparation process flow}
Next, a flow of processing in which the fax machine 100 prepares to transmit data from the fax machines 101 to 132 will be described. FIG. 3 is a flowchart showing a flow of processing in which the fax machine 100 prepares for transmission.

  The administrator of the fax machine 100 uses the session limit number setting unit 13 to set the session limit number. When setting the session limit number, the administrator considers other communications in which bandwidth and contention compete with each other. In FIG. 1, the other communication competing with the broadcast is IP telephone communication. Therefore, the administrator sets the session limit number to be small so that voice communication by IP telephone communication is not affected. As a result, the user can secure a wider IP telephone communication band than the simultaneous broadcast band. Alternatively, the administrator can use the session limit number set as a default value in the fax machine 100 even if the session limit number is not set.

  The administrator of the fax machine 100 uses the TOS value setting unit 14 to set the broadcast TOS value. When setting the TOS value for broadcast, the administrator also considers other communications in which the broadcast competes with the band. In FIG. 1, the administrator sets the TOS value for simultaneous broadcasting to be lower than the TOS value for IP telephone communication so that voice communication by IP telephone communication is not affected. As a result, the user can perform IP telephone communication with priority over simultaneous broadcasting. Alternatively, the administrator can use the TOS value set as the default value in the fax machine 100 even if the TOS value is not set.

  The user of the fax machine 100 uses the destination setting unit 11 to set IP addresses or host names and domain names from the fax machines 101 to 132. A user of the fax machine 100 inputs transmission data using the data input unit 12. Then, the user of the fax machine 100 gives a transmission instruction to the fax machine 100.

  The transmission unit 16 acquires information about the number of destinations from the destination setting unit 11. Further, the transmission unit 16 acquires transmission data from the data input unit 12. When transmitting unit 16 determines that the number of destinations is plural (YES in step S11), it performs simultaneous broadcast or sequential broadcast. When transmitting unit 16 determines that the number of destinations is one (NO in step S11), it is not necessary to perform simultaneous broadcast and sequential broadcast.

  The transmission unit 16 acquires information on the session limit number from the session limit number setting unit 13. When it is determined that there are a plurality of session limit numbers (YES in step S12), transmission unit 16 performs simultaneous broadcast. However, the transmission unit 16 limits the number of sessions connected simultaneously to the session limit number. When transmitting section 16 determines that the session limit number is one (NO in step S12), it sequentially broadcasts.

  A case where transmission unit 16 performs simultaneous broadcasting (YES in step S11 and YES in step S12) will be described. When QoS (Quality of Service) control by the router 3 is effective (YES in step S13), the transmission unit 16 adopts the TOS value for simultaneous broadcast as the TOS value (step S14). Even if the administrator of the fax machine 100 does not set the TOS value, the transmission unit 16 adopts a default value as the TOS value. When the QoS control by the router 3 is not valid (NO in step S13), the transmission unit 16 adopts a default TOS value as the TOS value (step S15). Since the QoS control by the router 3 is not effective, the TOS value has no particular significance, and the administrator of the fax machine 100 does not set the TOS value.

  A case where the transmission unit 16 transmits to one destination (NO in step S11) and a case where broadcasts are sequentially performed (YES in step S11 and NO in step S12) will be described. When the QoS control by the router 3 is valid (YES in step S16), the transmission unit 16 sequentially adopts the TOS value for broadcast as the TOS value (step S17). Even if the administrator of the fax machine 100 does not set the TOS value, the transmission unit 16 adopts a default value as the TOS value. When the QoS control by the router 3 is not valid (NO in step S16), the transmission unit 16 adopts a default TOS value as the TOS value (step S18).

  When the fax machine 100 executes steps S13 to S18, the router 3 can determine which communication should be prioritized among simultaneous broadcast, sequential broadcast, and other communication in which bandwidths compete. A method of setting the TOS value by the administrator of the fax machine 100 will be described later with reference to FIGS.

{Processing flow to reduce the session limit}
In the flow of processing in which the fax machine 100 prepares to transmit data, the administrator of the fax machine 100 sets the session limit number in consideration of other communications in which the broadcast and the bandwidth compete. However, even if the administrator of the fax machine 100 sets the session limit number, there is a possibility that other communications in which the bandwidth conflicts with the simultaneous broadcast may be affected.

  Therefore, a flow of processing for reducing the session limit number when bandwidth control is required when the fax machine 100 performs simultaneous broadcasting will be described. As processing flows performed by the fax machine 100, there are two different types of processing flows. First, the flow of the first process will be described with reference to FIGS. 4 and 5. Next, the flow of the second process will be described with reference to FIGS. 6 and 7.

  FIG. 4 is a flowchart showing the flow of the first process. When the transmission unit 16 needs retransmission control, the packet transmitted by the fax machine 100 is lost. Therefore, the session limit number setting unit 13 determines that the simultaneous broadcast is competing for bandwidth with other communications (YES in step S21).

  When session limit number setting unit 13 determines that transmission unit 16 requires bandwidth control (YES in step S21), session limit number setting unit 13 updates to reduce the session limit number (step S22). In other words, the transmission unit 16 disconnects the sessions connected at the same time by the reduced number of sessions. When the session limit number setting unit 13 determines that the transmission unit 16 does not require bandwidth control (NO in step S21), the session limit number setting unit 13 does not update the session limit number. That is, the transmission unit 16 continues the session to be connected at the same time.

  When transmission unit 16 finishes transmitting data to all destinations by the first simultaneous broadcast (YES in step S23), fax machine 100 ends the data transmission. If transmission unit 16 does not finish transmitting data to all destinations by the first simultaneous broadcast (NO in step S23), fax machine 100 repeats steps S21 to S23 until the data transmission is completed.

  FIG. 5 is a diagram showing a process flow in which simultaneous broadcast is performed each time in the first process flow. As shown in FIG. 1, the fax machine 100 performs simultaneous broadcasting to 32 fax machines 101 to 132 (YES in step S11). Time has elapsed as the vehicle moves from the upper stage to the lower stage, and the number of unsent destinations gradually decreases from 32.

  When the transmission unit 16 performs the first simultaneous broadcast, the number of sessions to which the transmission unit 16 is connected simultaneously is 8 as the session limit number (YES in step S12). Then, the session limit number setting unit 13 determines that the transmission unit 16 does not require bandwidth control (NO in step S21). Therefore, the session limit number setting unit 13 does not update the session limit number. When the transmission unit 16 finishes the first simultaneous broadcast, it has already transmitted data to the eight fax machines. Therefore, the number of unsent destinations has decreased to 24 (NO in step S23).

  When the transmission unit 16 performs the second simultaneous broadcast, the number of sessions to which the transmission unit 16 is connected simultaneously is 8 as the session limit number that has not been updated (YES in step S12). Then, session limit number setting unit 13 determines that transmission unit 16 requires bandwidth control (YES in step S21). Therefore, the session limit number setting unit 13 updates the session limit number to halve from 8 to 4 (step S22). When the transmission unit 16 finishes the second simultaneous broadcast, it has already transmitted data to the four fax machines. However, transmission of data to the other four fax machines is stopped. Therefore, the number of unsent destinations has decreased to 20 (NO in step S23).

  The flow of the process in which the transmission unit 16 performs the simultaneous broadcast after the third time is the same as the flow of the process in which the transmission unit 16 performs the simultaneous broadcast up to the second time. Each time the session limit number setting unit 13 determines that the transmission unit 16 needs bandwidth control (YES in step S21), the session limit number setting unit 13 immediately performs an update to decrease the session limit number in the simultaneous broadcast (step S22). . This reduced update of the session limit number is effective until the next update of the session limit number.

  FIG. 6 is a flowchart showing the flow of the second process. When session limit number setting unit 13 determines that transmission unit 16 requires bandwidth control (YES in step S31), session limitation number setting unit 13 does not limit transmission unit 16 from performing bandwidth control (step S32). When transmission unit 16 finishes transmitting data to all destinations by the first simultaneous broadcast (YES in step S33), fax machine 100 ends data transmission. If transmission unit 16 does not finish transmitting data to all destinations by the first simultaneous broadcast (NO in step S33), session limit number setting unit 13 updates to reduce the session limit number (step S34). The fax machine 100 repeats steps S31 to S35 until the data transmission is completed.

  When session limit number setting unit 13 determines that transmission unit 16 does not require bandwidth control (NO in step S31), session limit number setting unit 13 does not limit transmission unit 16 at all. When transmission unit 16 finishes transmitting data to all destinations by the first simultaneous broadcast (YES in step S35), fax machine 100 ends the data transmission. If transmission unit 16 does not finish transmitting data to all destinations by the first simultaneous broadcast (NO in step S35), fax machine 100 repeats steps S31 to S35 until the data transmission is completed.

  FIG. 7 is a diagram showing a process flow in which simultaneous broadcast is performed each time in the second process flow. When the transmission unit 16 performs the first simultaneous broadcast, the number of sessions to which the transmission unit 16 is connected simultaneously is 8 as the session limit number (YES in step S12). Then, the session limit number setting unit 13 determines that the transmission unit 16 does not require bandwidth control (NO in step S31). Therefore, the session limit number setting unit 13 does not update the session limit number. When the transmission unit 16 finishes the first simultaneous broadcast, it has already transmitted data to the eight fax machines. Therefore, the number of unsent destinations has decreased to 24 (NO in step S35).

  When the transmission unit 16 performs the second simultaneous broadcast, the number of sessions to which the transmission unit 16 is connected simultaneously is 8 as the session limit number that has not been updated (YES in step S12). Then, session limit number setting unit 13 determines that transmission unit 16 requires bandwidth control (YES in step S31). Therefore, the session limit number setting unit 13 does not limit the transmission unit 16 from performing bandwidth control (step S32). When the transmission unit 16 finishes the second simultaneous broadcast, it has already transmitted data to the eight fax machines. Therefore, the number of unsent destinations is reduced to 16 (NO in step S33). Then, the session limit number setting unit 13 updates the session limit number to halve from 8 to 4 as preparation for the third simultaneous broadcast (step S34).

  The flow of the process in which the transmission unit 16 performs the simultaneous broadcast after the third time is the same as the flow of the process in which the transmission unit 16 performs the simultaneous broadcast up to the second time. Even if session limit number setting unit 13 determines that transmission unit 16 needs bandwidth control (YES in step S31), update to reduce the session limit number is not immediately performed in the simultaneous broadcast (step S32). Then, the session limit number setting unit 13 performs an update to decrease the session limit number after the end of the simultaneous broadcast (step S34). This reduced update of the session limit number is effective until the next update of the session limit number.

  To summarize what has been described with reference to FIGS. In the first processing flow described with reference to FIGS. 4 and 5, when the transmission unit 16 requires bandwidth control, the number of sessions to be simultaneously connected is immediately determined even during the current simultaneous broadcast. Decrease. Then, the transmission unit 16 disconnects the session immediately decreased without performing band control. In the second processing flow described with reference to FIGS. 6 and 7, when the transmission unit 16 requires bandwidth control, the number of sessions connected simultaneously is not immediately reduced during the simultaneous broadcast at the present time. . And the transmission part 16 also maintains the session reduced later by performing band control.

  When comparing FIG. 5 and FIG. 7, considering the decrease in the number of untransmitted destinations, it is considered that the second processing flow has higher transmission capability than the first processing flow. However, when comparing FIG. 4 and FIG. 6, it is considered that the first processing flow has higher transmission capability than the second processing flow, considering whether the transmission unit 16 requires time for bandwidth control. It is done. Therefore, when the transmission data capacity is large, the first process flow may be performed in consideration of the time required for bandwidth control. In addition, when the transmission data capacity is small, the second process flow may be performed in consideration of the fact that bandwidth control does not require time.

  5 and 7, when the session limit number setting unit 13 determines that the transmission unit 16 needs bandwidth control, the session limit number setting unit 13 updates the session limit number by half. However, various forms are conceivable as the form in which the session limit number setting unit 13 performs the update for reducing the session limit number. For example, in FIG. 1, when the transmission data capacity of the IP telephone 2 is large, the session limit number setting unit 13 may reduce the session limit number by half or more. In FIG. 1, when the transmission data capacity of the IP telephone 2 is small, the session limit number setting unit 13 may decrease the session limit number one by one.

{Processing flow for increasing the session limit}
When the fax apparatus 100 requires bandwidth control, the fax apparatus 100 performs an update to reduce the session limit number. However, when the fax machine 100 does not require bandwidth control, it is not necessary to keep the session limit number reduced.

  Accordingly, a flow of processing for increasing the session limit number when bandwidth control is not required when the fax apparatus 100 performs simultaneous broadcasting will be described. As processing flows performed by the fax machine 100, there are two different types of processing flows. First, the flow of the third process will be described with reference to FIG. Next, the flow of the fourth process will be described with reference to FIG.

  FIG. 8 is a flowchart showing the flow of the third process. First, a description will be given of a case where the session limit number setting unit 13 determines that the transmission unit 16 needs bandwidth control in the N-th simultaneous broadcast (YES in step S41). At this time, the session limit number setting unit 13 does not update the session limit number in the (N + 1) th simultaneous broadcast to be larger than the session limit number in the Nth simultaneous broadcast.

  Next, the case where the session limit number setting unit 13 determines that the transmission unit 16 does not require bandwidth control in the N-th simultaneous broadcast (NO in step S41) will be described. At this time, the session limit number setting unit 13 updates the session limit number in the (N + 1) th simultaneous broadcast to be larger than the session limit number in the Nth simultaneous broadcast (step S42).

  FIG. 9 is a flowchart showing the flow of the fourth process. First, the case where the session limit number setting unit 13 determines that the transmission unit 16 needs bandwidth control in the N-th simultaneous broadcast will be described (YES in step S51). At this time, the session limit number setting unit 13 does not update the session limit number in the (N + 1) th simultaneous broadcast to be larger than the session limit number in the Nth simultaneous broadcast.

  Next, a description will be given of a case where the session limit number setting unit 13 determines that the transmission unit 16 does not require bandwidth control in the N-th simultaneous broadcast (NO in step S51). At this time, the session limit number setting unit 13 does not necessarily update the session limit number in the (N + 1) th simultaneous broadcast to be larger than the session limit number in the Nth simultaneous broadcast.

  The session limit number setting unit 13 determines whether a predetermined time has elapsed (step S52). For example, the predetermined time is the time that has elapsed since the transmission unit 16 last performed band control. The predetermined time is the time that has elapsed since the session limit number setting unit 13 last updated the session limit number.

  When session limit number setting unit 13 determines that the predetermined time has not elapsed (NO in step S52), session limit number in (N + 1) -th simultaneous broadcast is set as session limit number in N-th simultaneous broadcast. Do not make larger updates. When session limit number setting unit 13 determines that the predetermined time has elapsed (YES in step S52), session limit number in (N + 1) -th simultaneous broadcast is set as session limit number in N-th simultaneous broadcast. Updating to be larger is performed (step S53).

  When comparing FIG. 8 and FIG. 9, if the session limit number setting unit 13 considers whether or not the predetermined time has elapsed, the third processing flow is more simultaneous than the fourth processing flow. Can be efficient. However, the fourth processing flow can prevent the band occupation by simultaneous broadcasting more than the third processing flow. Therefore, when the time during which the other communication other than the simultaneous broadcast uses the band is short, the third processing flow may be performed. Further, when the communication other than the simultaneous broadcast uses a band for a long time, the fourth processing flow may be performed.

  Various modes are conceivable as the mode in which the session limit number setting unit 13 performs the update for increasing the session limit number. For example, in FIG. 1, when the IP telephone 2 is not frequently used, the session limit number setting unit 13 may increase the session limit number to the session limit number set by the administrator of the fax machine 100. The number of sessions may be increased beyond the limit set by the administrator of the fax machine 100 as long as voice communication by IP telephone communication is not affected. In addition, when the IP telephone 2 is frequently used in FIG. 1, the session limit number setting unit 13 may increase the session limit number one by one.

{Flow of transmission processing based on TOS value}
Next, a method in which the administrator of the fax machine 100 sets the TOS value when the fax machine 100 performs simultaneous broadcasting will be described. FIG. 10 is a diagram showing TOS values set as default values in the fax machine 100 and the IP telephone 2. FIG. 11 is a diagram showing TOS values set by the administrator for the fax machine 100 and the IP telephone 2.

  The TOS value is set to a value from 0 to 7 in decimal number. When the QoS control by the router 3 is valid, the communication with the high TOS value is prioritized over the communication with the low TOS value.

  In FIG. 10, 4 is set as the TOS value of Direct SMTP communication. Also, 6 is set as the TOS value for IP telephone communication. When the QoS control by the router 3 is effective, the router 3 can perform IP telephone communication with priority over Direct SMTP communication by referring to the TOS value.

  In FIG. 11, for Direct SMTP communication, 3 is set as the TOS value for simultaneous broadcasting, and 4 is set as the TOS value for simultaneous broadcasting. Also, 6 is set as the TOS value for IP telephone communication. That is, the administrator of the fax machine 100 newly sets a simultaneous broadcast TOS value for Direct SMTP communication. When QoS control by the router 3 is effective, the router 3 can preferentially perform IP telephone communication, sequential broadcast, and simultaneous broadcast in this order by referring to the TOS value.

  By using the TOS value described with reference to FIGS. 10 and 11, it is possible to prevent the voice communication by IP telephone communication from being affected. Further, by using the TOS value described with reference to FIG. 11, it is possible to prevent the broadcast band from being sequentially eroded by the simultaneous broadcast band in addition to the above-described effects.

It is a figure which shows the whole structure of a fax transmission / reception system. It is a block diagram which shows the component of a fax machine. 6 is a flowchart showing a flow of processing in which a fax machine prepares for transmission. 6 is a flowchart illustrating a flow of processing in which a fax machine performs transmission. It is a figure which shows the flow of the process in which simultaneous broadcast is performed each time. 6 is a flowchart illustrating a flow of processing in which a fax machine performs transmission. It is a figure which shows the flow of the process in which simultaneous broadcast is performed each time. 6 is a flowchart illustrating a flow of processing in which a fax machine performs transmission. 6 is a flowchart illustrating a flow of processing in which a fax machine performs transmission. It is a figure which shows the priority between the communication which a band competes. It is a figure which shows the priority between the communication which a band competes.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fax apparatus 2 IP telephone 3 Router 4 Internet 5 DNS server 6 DHCP server 11 Destination setting part 12 Data input part 13 Session limit number setting part 14 TOS value setting part 15 Data output part 16 Transmission part 17 Receiving part

Claims (4)

A transmitter that broadcasts to multiple destinations;
As an upper limit value of the number of sessions to which the transmission unit is connected simultaneously, a session limit number setting unit that sets a session limit number;
A data transmission device comprising: The data transmission device according to claim 1,
The session limit number setting unit includes:
Means for reducing the session limit when the transmission unit needs bandwidth control;
A data transmission apparatus comprising: The data transmission device according to claim 1 or 2,
The session limit number setting unit includes:
Means for increasing the session limit when the transmitter does not require bandwidth control;
A data transmission apparatus comprising: The data transmission device according to any one of claims 1 to 3, further comprising:
A priority setting unit for setting a priority for specifying whether or not simultaneous broadcast should be performed in preference to communication in which broadcast and bandwidth compete.
A data transmission device comprising:

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