JP5307341B2 - COMMUNICATION METHOD, COMMUNICATION SYSTEM, RELAY DEVICE, AND TERMINAL DEVICE - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To minimize a load for a relay network so as to make it possible to receive data in frequency bands requested by respective reception terminals when a plurality of terminals having different frequency bands to use are connected via a plurality of relay devices for group communication. <P>SOLUTION: When relaying a band command to specify a requested band, issued from reception terminals T2-T6 to a transmission terminal T1, relay devices C1-C3 store a maximum value of bands requested by a terminal and a relay device, which serve thereunder, whereas the transmission terminal T1 stores a maximum band of those of the reception terminals T2-T6. A transmission terminal T6 sets the stored band as a transmission band and transmits data. In the event of relay of the data, each of the relay devices C1-C3 buffers the data and relays them to the subordinates in bands specified, respectively, so that a transfer rate of the data relay between the relay devices is reduced to the minimum while the reception terminals T2-T6 can receive the data in their desired bands. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a communication system in which a plurality of terminal devices are connected to be able to communicate with each other via a plurality of relay devices, and more particularly to a communication system in which a receiving terminal requesting a wide band and a receiving terminal requesting a narrow band are mixed.

  In recent years, due to the development of network technology, various proposals or practical use of communication systems such as conference systems that connect remote terminal devices via a wide-band network via several relay devices and transmit and receive large amounts of data such as conference materials It has become. However, there is no guarantee that all terminal devices can use a certain bandwidth due to differences in the CPU power of each terminal device and the network bandwidth of the access network. For this reason, there is a demand for a method capable of efficiently communicating in a situation where a receiving terminal requesting a wide band and a receiving terminal requesting a narrow band coexist.

  In a communication system in which receiving terminals having different bandwidths are mixed, an example of a communication method that enables all receiving terminals to receive data without any problem is that a transmitting terminal transmits data in the lowest band among all receiving terminals, This is a method in which each relay device relays the data and delivers it to each receiving terminal (hereinafter, this method is referred to as a first prior art).

  In a communication system in which receiving terminals having different bandwidths are mixed, another example of a communication method that enables all receiving terminals to receive data without any problem is that the transmitting terminal is separately configured with a transmission band suitable for the band of each receiving terminal. In this method, data is transmitted, and each relay device relays the data and delivers it to each receiving terminal (hereinafter, this method is referred to as a second conventional technique).

  In the first conventional technique and the second conventional technique, there is a method using a resource reservation protocol (RSVP) in order to allow a transmitting terminal to transmit data in a desired band. Yes (see, for example, Patent Document 1).

JP 2000-106568 A

  However, in the first prior art described above, a receiving terminal that requires a wide band cannot receive data in a band that matches its own ability. Further, according to the second prior art, data can be received in a band optimum for all receiving terminals, but the load increases because the transmitting terminal needs to transmit the same data separately to a plurality of bands. Also, the bandwidth between the relay devices is required to be the sum of the bandwidths of the receiving terminals relayed therethrough, increasing the network load.

  An object of the present invention is to provide data in an optimum band for all receiving terminals in a communication system in which a receiving terminal requesting a wide band and a receiving terminal requesting a narrow band are mixed while suppressing an increase in the load on the transmitting terminal and the network. Is to be able to receive.

  According to a first communication method of the present invention, there is provided a communication method in a communication system in which a plurality of terminal devices are connected to each other via a plurality of relay devices so that a) a terminal device on the data receiving side is in the same communication group Transmitting a bandwidth command designating a desired transmission bandwidth to the data transmission side terminal device, and b) when the relay device relays the bandwidth command, the received bandwidth command is transmitted to the local relay device. For each communication group stored in the transfer band storage device, for each terminal device connected to its own relay device and other relay devices, the maximum transmission bandwidth of the bandwidth command received from each is calculated for each communication group A step of storing in the transfer band storage device, and c) the terminal device on the data transmission side receiving the band command stores the received band command in the transmission band of its own terminal device Storing for each communication group at the same time, calculating the maximum transmission bandwidth of the received bandwidth command for each communication group and storing it in the transmission bandwidth storage device, and d) the terminal device on the data transmission side is the same Dividing the data to be transmitted to the terminal device on the data receiving side of the communication group into data of a certain length, and transmitting each divided data in the maximum transmission band stored in the transmission band storage device; e) the relay When the device relays the divided data, it buffers the received divided data in the transfer data temporary storage device, and stores the transfer band of the own relay device for each terminal device and other relay devices connected to the own relay device. Relaying the transfer data with the maximum transmission bandwidth stored in the device; and f) the terminal device on the data receiving side receiving the divided data receives the original data from the divided data. Characterized in that it comprises the steps of synthesizing.

  According to a second communication method of the present invention, in the first communication method, the bandwidth command includes a priority related to a designated transmission bandwidth, and the maximum transmission bandwidth of the bandwidth command is the step b and the step c. In addition, the maximum priority is calculated and stored, and in step d and step e, control is performed to reduce the transmission band of lower priority data when the communication amount exceeds a predetermined amount. It is characterized by performing.

  According to a third communication method of the present invention, in the first communication method, when the terminal device on the data receiving side logs out from the communication group, the bandwidth command output from the logged out terminal device is transmitted to the relay device. Transfer bandwidth storage device and the data transmission side terminal device from the transmission bandwidth storage device, and the relay device and the data transmission side terminal device recalculate the maximum transmission bandwidth based on the remaining bandwidth commands. It is characterized by doing.

  The first relay device according to the present invention is a relay device in a communication system in which a plurality of terminal devices are communicably connected to each other via a plurality of relay devices, and transmits data transmitted from the terminal device on the data transmission side. Communication means for communicating with the terminal device and other relay devices to relay to the terminal device on the data receiving side, the transfer band storage device, the transfer data temporary storage device, and the same communication group from the terminal device on the data receiving side When the communication means relays a band command specifying a transmission band transmitted to the terminal device on the data transmission side, the band command is stored in the transfer band storage device for each communication group, and the own relay device For each terminal group and other relay devices connected to the network, the maximum transmission bandwidth of the bandwidth command received from them is calculated for each communication group, and the transfer bandwidth Band totaling means to be stored in the storage device, and data transmitted from the data transmission side terminal device to the data reception side terminal device of the same communication group are buffered in the transfer data temporary storage device and connected to the own relay device And a transmission timing control means for relaying transfer data in the maximum transmission band stored in the transfer band storage device for each of the terminal devices and other relay devices.

  The second relay device according to the present invention is the first relay device, wherein the bandwidth command includes a priority related to a designated transmission bandwidth, and the bandwidth aggregation means includes a maximum bandwidth in addition to the bandwidth command maximum transmission bandwidth. Is calculated and stored in the transfer band storage device, and the transmission timing control means performs control to reduce the transmission band of lower priority data when the communication amount exceeds a predetermined amount It is characterized by that.

  In the third relay device of the present invention, when the communication unit relays a logout command indicating that the terminal device on the data receiving side has logged out of the communication group in the first relay device, The bandwidth command of the terminal device that has logged out is deleted from the transfer bandwidth storage device, and the maximum transmission bandwidth is recalculated based on the remaining bandwidth commands.

  The first terminal device of the present invention communicates with another terminal device through the relay device in the terminal device in the communication system in which a plurality of terminal devices are connected to each other via a plurality of relay devices. When the communication means, the transmission band storage device, and the own terminal device become the data reception side terminal device, a band command specifying the desired transmission band is transmitted to the data transmission side terminal device of the same communication group. When the local terminal device becomes a data transmission side terminal device, when the local terminal device becomes a data transmission side terminal device and an application that transmits data to the data reception side terminal of the same communication group The bandwidth command received from the terminal device on the data receiving side is stored in the transmission bandwidth storage device for each communication group, and the maximum transmission of the received bandwidth command is performed. An arbitration unit that calculates a region for each communication group and stores it in the transmission band storage device, a division unit that generates divided data obtained by dividing the data transmitted from the application into data of a certain length, and generated by the division unit Transmission timing designating means for transmitting the divided data by the communication means in the maximum transmission band stored in the transmission band storage device, and combining means for combining the original data from the divided data received by the communication means It is characterized by providing.

  According to a second terminal device of the present invention, in the first terminal device, the bandwidth command includes a priority related to a designated transmission bandwidth, and the arbitration means includes a maximum transmission bandwidth of the bandwidth command in addition to the maximum transmission bandwidth. Priority is calculated and stored in the transmission band storage device, and the transmission timing control means performs control to reduce the transmission band of lower priority data when the communication amount exceeds a predetermined amount It is characterized by.

  When the communication unit relays a logout command to the effect that the terminal device on the data receiving side has logged out of the communication group, the arbitration unit is configured to transmit the bandwidth of the terminal device that has logged out. The command is deleted from the transmission bandwidth storage device, and the maximum transmission bandwidth is recalculated based on the remaining bandwidth commands.

  The communication system of the present invention is a communication system in which a plurality of terminal devices are connected so as to communicate with each other via a plurality of relay devices, and the terminal device is the first, second or third terminal device, The relay device is a first, second, or third relay device.

"Action"
Unlike stream delivery, data transmitted from a data system application has burstiness, so data does not always flow. For this reason, if buffering is performed with the transfer data temporary storage device provided to the relay device, the bandwidth of the transmission data can be converted to another bandwidth by the relay device. The present invention pays attention to this point, and data is transmitted from the terminal device on the transmission side in the maximum bandwidth among the bandwidths required by the terminal device on the reception side. Each relay device converts the received transmission data band into a band suitable for other lower relay devices or terminal devices and relays the converted data. Thus, the object of the present invention can be achieved.

  According to the present invention, in a communication system in which a receiving terminal requesting a wide band and a receiving terminal requesting a narrow band are mixed, data in an optimum band for all the receiving terminals while suppressing an increase in load on the transmitting terminal and the network. Can be received.

  The reason why the increase in the load on the transmitting terminal can be suppressed is that the transmitting-side terminal device only needs to transmit data in the maximum bandwidth among the plurality of receiving-side terminal devices, even if each of the receiving-side terminal devices requests different bandwidths. Because. The reason why the increase in network load can be suppressed is that each relay device can secure only the maximum bandwidth among subordinate receiving terminals even if a plurality of receiving-side terminal devices request different bandwidths. Because it is good. Furthermore, the reason why data can be received in the optimum band for all receiving terminals is that each relay apparatus converts the received transmission data band into a band suitable for the terminal apparatus on the data receiving side and relays it. .

  Next, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  Referring to FIG. 1, an example of a communication system according to the present invention includes terminal devices T1 to T6 and relay devices C1 to C3. The terminal devices T1, T2, and T3 are connected to the relay device C1 through lines L1, L2, and L3. Terminal apparatuses T4 and T5 are connected to relay apparatus C3 through lines L4 and L5, and terminal apparatus T6 is connected to relay apparatus C2 through line L6. Further, the relay device C1 and the relay device C2 are connected through the relay line C12, and the relay device C2 and the relay device C3 are connected through the relay line C23.

  When the terminal devices T1 to T6 are logged in to a certain communication group, the data transmitted from each of the terminal devices T1 to T6 to the communication group is transmitted to all other terminal devices that are logged into the communication group. Delivered. For example, data transmitted from the terminal device T1 to the line L1 is first received by the relay device C1, and transmitted from the relay device C1 to the terminal devices T2 and T3 through the lines L2 and L3, and at the same time relayed through the trunk line C12. It is transmitted to the device C2. Further, the relay device C2 transmits the received data to the terminal T6 through the line L6 and transmits it to the relay device C3 through the relay line C23. Further, the relay device C3 transmits the received data to the terminal devices T4 and T5 through the lines L4 and L5.

  In the present embodiment, in a communication system in which group communication is performed as described above, when a plurality of terminal devices that receive data request different bands, an increase in the load on the relay line between the transmission terminal and the relay device In addition, it is possible to receive data in an optimum band for all receiving terminals. Hereinafter, for convenience of explanation, the terminal device T1 is a terminal device on the data transmission side, and the terminal devices T2 to T6 are terminal devices on the data reception side, but each of the terminal devices T1 to T6 is a terminal device on the data transmission side and It can operate as any terminal device on the data receiving side.

  Next, the terminal devices T1 to T6 and the relay devices C1 to C3 will be described in detail.

  Referring to FIG. 2, the terminal device 100 that can be used as the terminal devices T1 to T6 includes a communication unit 101, a receiving unit 102, a combining unit 103, a band receiving unit 104, an arbitration unit 105, an application 106, a dividing unit 107, and a band setting. Means 108, transmission timing control means 109, flow rate detection means 110, and transmission band storage device 111 are configured.

  The communication unit 101 is a unit that transmits and receives data to and from the relay device connected to the terminal device 100. The data to be transmitted / received are the login / logout command D10, the band command D20, and the divided data D30 shown in FIG.

  The login logout command D10 is used when the terminal device participates in the group communication or withdraws from the group communication in which the terminal device participated, and a group identifier (GID) D11 for uniquely identifying the communication group, the login logout command D10 It consists of a transmission source identifier (From) D12, a transmission destination identifier (To) of the login logout command D10, and a command (login command or logout command) D14.

  The bandwidth command D20 is used when notifying a desired transmission bandwidth from a terminal that is a data reception side to a terminal that is a data transmission side, and includes a group identifier D21, a transmission source identifier D22, a transmission destination identifier D23, It has a command D24, a priority D25, and a band D26. The priority D25 is a numerical value. Here, the higher the numerical value, the higher the priority. When it is not desired to reduce the actual communication band from the band designated by the band D26, a higher priority is set. Band D26 is not a reserved band, but an actual band.

  The divided data D30 is used when transmitting / receiving text data, image data, and the like transmitted from the transmitting terminal to the receiving terminal by dividing the data into fixed-length data, and includes a group identifier D31, a transmission source identifier D32, and a transmission destination. It has an identifier D33, a command D34, a division number D35, and division data D36. The division number D35 is a serial number indicating what number of the series of division data the division data D36 is.

  Referring to FIG. 2 again, the receiving unit 102 receives the data received from the relay device by the terminal device from the communication unit 101, analyzes the command type of the data, and transmits the data to the synthesizing unit 103 if the data is divided data D30. The bandwidth command D20 and the login / logout command D10 are transmitted to the bandwidth receiving means 104.

  When the band receiving unit 104 receives the band command D20 from the receiving unit 102, the band receiving unit 104 transmits the band information of the receiving terminal to the arbitrating unit 105 in order to manage it in its own terminal, and receives the login logout command D10 from the receiving unit 202. In this case, the information is transmitted to the application 106, and if it is a logout command, the bandwidth information of the logged-out receiving terminal is also transmitted to the arbitrating means 105 in order to delete it from the management of the own terminal.

  The synthesizing unit 103 buffers the plurality of divided data D30 received from the receiving unit 102 in an internal memory, and concatenates the divided data D36 in the order of the division number D35 in each divided data D30. The data is synthesized and transmitted to the application 106. FIG. 3 shows a format example of the data D40 notified from the synthesizing unit 103 to the application 106. Data D44 is data obtained by combining a plurality of divided data D36, and D41, D42, and D43 are a group identifier D31, a transmission source identifier D32, and a transmission destination identifier D33 added to each divided data D30.

  When the own terminal device 100 is on the transmission side, the arbitrating means 105 determines the divided data D30 from the own terminal device based on the band command D20 and the logout command D10 received from the receiving terminal device. It is calculated whether it should be relayed to the relay device at a time, and the calculation result is stored in the transmission band storage device 111. More specifically, the process shown in FIG. 4 is executed.

  First, the arbitrating means 105 determines whether the received command is the bandwidth command D20 or the logout command D10 (step S101). If the command is the bandwidth command D20, the bandwidth command D20 is stored in the transmission bandwidth storage in association with the group identifier D21. It memorize | stores in the apparatus 111 (step S102). Then, the maximum value of all the bandwidth commands D20 stored in association with the group identifier D21 is calculated (step S104). For example, when a band command D20 of (band 100, priority 3), (band 200, priority 5) is received from each of the terminal devices A and B, the band 200 and priority 5 are set to the maximum values. To do. On the other hand, if the logout command D10 is received (step S101), the bandwidth command issued by the terminal device that logged out is deleted from the transmission bandwidth storage device 111 (step S103). Then, the maximum value of all the bandwidth commands D20 stored in association with the group identifier D21 is calculated again (step S104).

  The application 106 is an arbitrary application program that runs on the terminal device 100. When the application 106 transmits data from its own terminal device 100 to an application of another terminal device, the application 106 transmits the data in the format indicated by the data D40 in FIG. When receiving data from an application of another terminal device, the application 106 notifies the transmitting side terminal device of the bandwidth command of FIG. 3 in which the desired transmission bandwidth and priority are set through the communication unit 101. Further, the application 106 notifies the communication group 101 of the login / logout command D10 to the outside through the communication unit 101.

  The dividing unit 107 divides the data D40 sent from the application 106 into a plurality of divided data D30 and transmits the divided data D30 to the transmission timing control unit 109. More specifically, the data D44 in the data D40 is divided into data of a certain length, and the group identifier D41, the transmission source identifier D42, and the transmission destination identifier D43 in the data D40 are divided into the respective data. A transmission source identifier D32 and a transmission destination identifier D33 are assigned, and a command D34 and a division number D35 indicating that the data is divided data are further assigned to generate divided data D30. Then, the division data D30 is output to the transmission timing control means 109 in order from the smallest division number D35.

  Band setting unit 108 sets the maximum band and priority calculated by arbitration unit 105 and stored in transmission band storage device 111 as the transmission band and priority in transmission timing control unit 109. Note that the bandwidth setting unit 108 determines that the maximum transmission bandwidth of the local terminal device is transmitted to the transmission timing control unit 109 when the maximum bandwidth stored in the transmission bandwidth storage device 111 exceeds the maximum transmission bandwidth of the local terminal device. Set to the transmission band.

  The flow rate detection unit 110 detects the flow rate of data transmitted from the communication unit 101, and sends a band break notification to the transmission timing control unit 109 when the detected flow rate exceeds a predetermined maximum bandwidth.

  The transmission timing control unit 109 controls the transmission timing of each divided data D30 so that the divided data D30 received from the dividing unit 107 is transmitted from the communication unit 101 in the transmission band set by the band setting unit 108. When a band break notification is received from the flow rate detection means 107 during this control, the flow rate is suppressed so that the band break notification is not issued by expanding the transmission timing. At this time, if there is a plurality of transmission data with different priorities, the transmission timing is expanded in order from the lower priority data so that the higher priority data is transmitted in the designated band. To do.

  Referring to FIG. 5, the relay apparatus 200 that can be used as the relay apparatuses C1 to C3 includes a communication unit 201, a reception unit 202, a communication group control unit 203, a transmission timing designation unit 204, a transmission timing control unit 205, and a band totaling unit 206. The transfer band storage device 300 and the transfer data temporary storage device 400 are connected to each other.

  The communication unit 201 exchanges data with other relay devices and terminal devices connected to the own relay device 200. When the communication unit 201 receives the login / logout command D10 and the bandwidth command D20 from other relay devices and terminal devices, the communication unit 201 captures them and transmits them to the reception unit 202, and at the same time, retransmits (relays) them to the destination. To do. In addition, when the communication unit 201 receives the divided data D30 from other relay devices and terminal devices, the communication unit 201 captures the divided data D30 and transmits the divided data D30 to the receiving unit 202, and then the transmission timing control unit 205 receives the divided data D30. When transmission is instructed, retransmission (relay) is performed toward the destination.

  The receiving unit 202 receives data received from other relay devices and terminal devices from the communication unit 201, analyzes the command type of the data, accumulates the divided data D30 in the transfer data temporary storage device 400, and logs in If it is a command D10, it is transmitted to the communication group control means 203, if it is a command D10 for logout, it is transmitted to the communication group control means 203 and the band totaling means 206, and if it is a band command D20, it is transmitted to the band totaling means 206.

  Based on the logout logout command D <b> 10, the communication group control unit 203 receives the divided data D <b> 30 transmitted from the terminal device belonging to the communication group for each communication group when the own relay device 200 receives the divided data D <b> 30. Relay information indicating to which other relay devices and terminal devices to be connected that the divided data D30 should be relayed is managed, and the relay destination of the divided data D30 is designated to the transmission timing designation means 204.

  Based on the bandwidth command D20 and the logout command D10, the bandwidth totalizing unit 206 determines, for each communication group, the divided data D30 transmitted from the terminal device belonging to the communication group to the same destination with any bandwidth and priority. Whether to relay to the relay device and the terminal device is calculated, and the calculation result is stored in the transfer bandwidth storage device 300. More specifically, the process shown in FIG. 6 is executed.

  First, the bandwidth totalizing unit 206 determines whether the received command is the bandwidth command D20 or the logout command D10 (step S201). If the command is the bandwidth command D20, the bandwidth command D20 is associated with the group identifier D21 and the destination. The data is stored in the transfer band storage device 300 (step S202). Next, it is determined whether the bandwidth command D20 has been received directly from the terminal device or via another relay device (step S204). If it is via another relay device, the bandwidth via that relay device is determined. The maximum value of the command is calculated (step S205). For example, when a band command D20 of (Band 100, Priority 3), (Band 200, Priority 5) is received from each of the terminal devices A and B via a certain relay device, for example, via the relay device The bandwidth 200 and the priority 5 are calculated as the maximum value of the bandwidth command. Next, if the bandwidth storage D50 in the format as shown in FIG. 3 is not generated for the relay device, it is newly generated, and if it has already been generated, it is updated as necessary (step S206). At this time, the identifier of the communication group is set in the group identifier D51, the transmission destination identifier D23 of the bandwidth command D20 is set in the transmission source identifier D52, the relay device is set in the transmission destination identifier D53, and the priority is set. The calculated maximum value is set in D54 and band D55.

  Also, if the current bandwidth command D20 is received directly from the terminal device (YES in step S204), if the bandwidth storage D50 is not generated for the terminal device, it is newly generated, and if it is already generated Update as necessary (step S207). At this time, the identifier of the communication group is set in the group identifier D51, the transmission destination identifier D23 of the bandwidth command D20 is set in the transmission source identifier D52, the terminal device is set in the transmission destination identifier D53, and the priority is set. In D54 and band D55, the priority D25 and band D26 of the band command D20 received this time are set.

  On the other hand, if the logout command D10 is received (step S201), the bandwidth command issued from the terminal device that logged out is deleted from the transfer bandwidth storage device 300 (step S203). And the process after step S204 is performed. Accordingly, if the logout command D10 is directly received from the terminal device (YES in step S204), the bandwidth storage D50 for the terminal device is deleted from the transfer bandwidth storage device 300 (step S207). If the logout command D10 is received via another relay device (NO in step S204), the maximum value of the bandwidth command via the relay device is recalculated (step S205). For example, in a situation where a band command D20 of (band 100, priority 3), (band 200, priority 5), for example, is received from each of the terminal apparatuses A and B via a certain relay apparatus, the terminal apparatus B When the logout command D10 is received, the maximum value of the bandwidth command via the relay device becomes the bandwidth 100 and the priority 3. Next, the bandwidth storage D50 for the relay device is updated or deleted as necessary.

  The transmission timing designation unit 204 controls the transmission timing control unit 205 so as to transfer data to the relay partner designated by the communication group control unit 203. At that time, the transfer band D55 and the priority D54 are extracted for each transfer partner D53 from the band storage D50 stored in the transfer band storage device 300 and transmitted to the transmission timing control means 205.

  The flow rate detection unit 207 detects the communication flow rate of the communication unit 201 for each line, and when exceeding a predetermined flow rate, notifies the transmission timing control unit 205 of the band breakthrough.

  The transmission timing control means 205 is configured so that the divided data D30 read from the transfer data temporary storage device 400 is transmitted from the communication means 201 to the relay destination in the transmission band set by the transmission timing designation means 204. The transmission timing of D30 is controlled. When a bandwidth break notification is received for a certain line from the flow rate detection means 207 during this control, the transmission timing is expanded to suppress the flow rate so that there is no bandwidth break notification for that line. At this time, if there is a plurality of transmission data with different priorities, the transmission timing is expanded in order from the lower priority data so that the higher priority data is transmitted in the designated band. To do.

  Next, the operation of the present embodiment will be described. As a situation, the six terminal devices T1 to T6 shown in FIG. 1 are logged in to the same communication group g, and the terminal device T1 is the transmitting side and the remaining terminal devices T2 to T6 are the receiving side to perform group communication. Consider an example.

First, the operation when the terminal devices T2 to T6 transmit the bandwidth command D20 to the terminal device T1 to set the bandwidth will be described. The order in which the terminal devices T2 to T6 send the band command, the designated band, and the priority thereof are as follows. The band unit is, for example, Mbit / s, and the terminal apparatus T1 has a maximum transmission band of 400 or more.
(1) Terminal device T2: bandwidth 100, priority 1
(2) Terminal device T3: bandwidth 200, priority 2
(3) Terminal device T4: bandwidth 300, priority 3
(4) Terminal device T5: bandwidth 200, priority 2
(5) Terminal device T6: bandwidth 400, priority 4

  When the application 106 of the terminal device T2 transmits the band command D20 addressed to the terminal device T1 to the relay device C1 through the communication unit 101, the communication unit 201 of the relay device C1 receives this and receives it to the band totaling unit 206 through the reception unit 202. At the same time as transmission, relay to the terminal device T1. The bandwidth totalization means 206 of the relay device C1 stores the bandwidth command D20 of the terminal device T2 in association with the communication group g in the transfer bandwidth storage device 300, generates the bandwidth storage D50 for the terminal device T2, and generates the transfer bandwidth storage device. 300. At this time, the contents of the bandwidth storage D50 for the terminal device T2 are as shown in FIG. Also, the band command D20 from the terminal device T2 received by the terminal device T1 is transmitted to the arbitration unit 105 through the communication unit 101, the reception unit 102, and the band reception unit 104, and the arbitration unit 105 transmits the band command D20. In addition to being stored in the band storage device 111, the maximum value of the transmission band is calculated as 100 and the priority is calculated as 1 and stored in the transmission band storage device 111 as shown in FIG.

  Next, when the application 106 of the terminal device T3 transmits the bandwidth command D20 addressed to the terminal device T1 to the relay device C1 through the communication means 101, the communication means 201 of the relay device C1 receives this and aggregates the bandwidth through the reception means 202. At the same time as it is transmitted to the means 206, it is relayed to the terminal device T1. The bandwidth totalization means 206 of the relay device C1 stores the bandwidth command D20 of the terminal device T3 in association with the communication group g in the transfer bandwidth storage device 300, generates the bandwidth storage D50 for the terminal device T3, and generates the transfer bandwidth storage device. 300. At this time, the contents of the bandwidth storage D50 for the terminal device T3 are as shown in FIG. The band command D20 received from the terminal device T3 by the terminal device T1 is transmitted to the arbitration unit 105 through the communication unit 101, the reception unit 102, and the band reception unit 104, and the arbitration unit 105 transmits the band command D20. While being stored in the band storage device 111, the maximum value of the transmission band is updated to 200 and the priority is updated to 2 as shown in FIG.

  Next, when the application 106 of the terminal device T4 transmits a bandwidth command D20 addressed to the terminal device T1 to the relay device C3 through the communication unit 101, the communication unit 201 of the relay device C3 receives this and receives the bandwidth total through the reception unit 202. At the same time as it is transmitted to the means 206, it is relayed to the relay device C2. The bandwidth totalization means 206 of the relay device C3 stores the bandwidth command D20 of the terminal device T4 in association with the communication group g in the transfer bandwidth storage device 300, generates the bandwidth storage D50 for the terminal device T4, and transfers the bandwidth storage device. 300. At this time, the contents of the bandwidth storage D50 for the terminal device T4 are as shown in FIG.

  When the communication unit 201 of the relay device C2 receives the bandwidth command D20 from the terminal device T4 transmitted from the relay device C3, the communication unit 201 transmits the bandwidth command D20 to the bandwidth aggregation unit 206 through the reception unit 202 and simultaneously relays it to the relay device C1. Since the bandwidth totalization means 206 of the relay device C2 stores the bandwidth command D20 of the terminal device T4 in association with the communication group g in the transfer bandwidth storage device 300 and receives the bandwidth command D20 of the terminal device T4 from the relay device C3. A bandwidth storage D50 for the relay device C3 is generated and stored in the transfer bandwidth storage device 300. At this time, the contents of the bandwidth storage D50 for the relay device C3 are as shown in FIG.

  When receiving the bandwidth command D20 from the terminal device T4 transmitted from the relay device C2, the communication unit 201 of the relay device C1 transmits the bandwidth command D20 to the bandwidth counting unit 206 through the reception unit 202 and simultaneously relays it to the terminal device T1. Since the bandwidth totalization means 206 of the relay device C1 stores the bandwidth command D20 of the terminal device T4 in association with the communication group g in the transfer bandwidth storage device 300 and receives the bandwidth command D20 of the terminal device T4 from the relay device C2, A bandwidth storage D50 for the relay device C2 is generated and stored in the transfer bandwidth storage device 300. At this time, the contents of the bandwidth storage D50 for the relay device C2 are as shown in FIG. Also, the band command D20 received from the terminal apparatus T4 from the terminal apparatus T1 is transmitted to the arbitration means 105 through the communication means 101, the reception means 102, and the band reception means 104, and the arbitration means 105 transmits this band command D20. While being stored in the band storage device 111, the maximum value of the transmission band is updated to 300 and the priority is updated to 3, as shown in FIG.

  Next, when the application 106 of the terminal device T5 transmits a bandwidth command D20 addressed to the terminal device T1 to the relay device C3 through the communication unit 101, the communication unit 201 of the relay device C3 receives this and aggregates the bandwidth through the reception unit 202. At the same time as it is transmitted to the means 206, it is relayed to the relay device C2. The bandwidth totalization means 206 of the relay device C3 stores the bandwidth command D20 of the terminal device T4 in association with the communication group g in the transfer bandwidth storage device 300, generates the bandwidth storage D50 for the terminal device T5, and generates the transfer bandwidth storage device. 300. At this time, the contents of the bandwidth storage D50 for the terminal device T5 are as shown in FIG.

  When the communication unit 201 of the relay device C2 receives the band command D20 transmitted from the relay device C3 from the terminal device T5, the communication unit 201 transmits the bandwidth command D20 to the band totaling unit 206 through the reception unit 202 and simultaneously relays it to the relay device C1. The band totaling unit 206 of the relay apparatus C2 stores the band command D20 of the terminal apparatus T5 in the transfer band storage apparatus 300 in association with the communication group g. In addition, since the band command addressed to the terminal device T1 received from the relay device C3 is two from the terminal device T4 and the current terminal device T5, the maximum value is calculated and the relay device is calculated. The bandwidth storage D50 for C3 is updated. In this case, there is virtually no change in value. That is, the contents of the bandwidth storage D50 for the relay device C3 are the same as in FIG. 9, as shown in FIG.

  When the communication unit 201 of the relay device C1 receives the bandwidth command D20 transmitted from the relay device C2 from the terminal device T5, the communication unit 201 transmits the bandwidth command D20 to the bandwidth aggregation unit 206 through the reception unit 202 and simultaneously relays it to the terminal device T1. The band totaling unit 206 of the relay apparatus C1 stores the band command D20 of the terminal apparatus T5 in the transfer band storage apparatus 300 in association with the communication group g. Further, since the band command addressed to the terminal device T1 received from the relay device C2 is two from the terminal device T4 and the current terminal device T5, the maximum value is calculated and the relay device is calculated. The bandwidth storage D50 for C2 is updated. In this case, there is virtually no change in value. That is, the contents of the bandwidth storage D50 for the relay device C2 are the same as in FIG. 9, as shown in FIG.

  Further, the band command D20 received from the terminal apparatus T1 from the terminal apparatus T1 is transmitted to the arbitration means 105 through the communication means 101, the reception means 102, and the band reception means 104, and the arbitration means 105 transmits the band command D20. Store in the band storage device 111. However, as shown in FIG. 10, the maximum value 300 and priority 3 of the transmission band are not updated as in FIG.

  Finally, when the application 106 of the terminal device T6 transmits a bandwidth command D20 addressed to the terminal device T1 to the relay device C2 through the communication unit 101, the communication unit 201 of the relay device C2 receives this and aggregates the bandwidth through the reception unit 202. At the same time as it is transmitted to the means 206, it is relayed to the relay device C1. The bandwidth totalization means 206 of the relay device C2 stores the bandwidth command D20 of the terminal device T6 in association with the communication group g in the transfer bandwidth storage device 300, generates the bandwidth storage D50 for the terminal device T6, and generates the transfer bandwidth storage device. 300. At this time, the contents of the bandwidth storage D50 for the terminal device T6 are as shown in FIG.

  When the communication unit 201 of the relay device C1 receives the bandwidth command D20 transmitted from the relay device C2 from the terminal device T6, the communication unit 201 transmits the bandwidth command D20 to the bandwidth counting unit 206 through the reception unit 202 and simultaneously relays it to the terminal device T1. The band totaling unit 206 of the relay apparatus C1 stores the band command D20 of the terminal apparatus T6 in the transfer band storage apparatus 300 in association with the communication group g. Further, since the band commands addressed to the terminal device T1 received from the relay device C3 are three from the terminal devices T4 and T5 and from the current terminal device T6, the maximum value is calculated, The bandwidth storage D50 for the relay device C3 is updated. As a result, the contents of the bandwidth storage D50 for the relay device C3 are updated to 400 for the bandwidth and 4 for the priority as shown in FIG.

  The band command D20 from the terminal apparatus T6 received by the terminal apparatus T1 is transmitted to the arbitrating means 105 through the communication means 101, the receiving means 102, and the band receiving means 104, and the arbitrating means 105 stores the band command D20 in the transmission band storage. Store in device 111. Also, as shown in FIG. 11, the maximum value of the transmission band is updated to 400 and the priority is updated to 4.

  Next, an operation when data is transmitted from the terminal device T1 to the communication group g after all the band commands D20 of the terminals T2 to T6 have been processed will be described.

  When the application 106 of the terminal device T1 transmits the data D40 to the dividing unit 107, the dividing unit 107 divides it into a plurality of divided data D30 and outputs it to the transmission timing control unit 109. On the other hand, the band setting unit 108 sets the transmission band 400 and the priority 4 stored in the transmission band storage device 111 in the transmission timing control unit 109. As a result, the transmission timing control unit 109 controls the transmission timing of the divided data D30 in the communication unit 101 so that the transmission band of the divided data D30 output from the dividing unit 107 matches 400. At this time, when a notification of band breakage is received from the flow rate detection means 110, the transmission timing is expanded in order from the communication data with the lowest priority.

  The divided data D30 transmitted from the terminal device T1 through the line L1 is received by the communication unit 201 of the relay device C1, and is buffered in the transfer data temporary storage device 400 through the reception unit 202. On the other hand, the communication group control unit 203 managing the relay destination of the communication group g should transfer the data received from the terminal device T1 to the relay device C2 and the terminal devices T2 and T3 with respect to the transmission timing designating unit 204. Specify that. For each designated transfer destination, the transmission timing specifying means 204 reads the transfer destination bandwidth storage D50 from the transfer bandwidth storage device 300, and the divided data D30 read from the transfer data temporary storage device 400 is transferred by the transfer bandwidth D50. The transmission timing of each divided data D30 is controlled so that it is transmitted from the communication means 101 in the set transmission band. When a band breakthrough notification is received from the flow rate detecting means 207 during this control, the flow rate is suppressed so that the band breakthrough notification is not issued by expanding the transmission timing. At this time, if there is a plurality of transmission data with different priorities for each line, the transmission timing is expanded in order from the data with lower priority, so that the data with higher priority is specified in the specified band. To be sent. In the case of FIG. 11, the relay device C1 transmits the divided data D30 from the terminal device T1 received in the band 400 to the terminal device T2 through the line L2 with the band 100 and priority 1, and to the terminal device T3 the line L3. Is transmitted with a bandwidth of 200 and a priority of 2, and is transmitted to the relay apparatus C2 with a bandwidth of 400 and a priority of 4 through the trunk line C12.

  Here, when the data received in the band 400 is buffered in the transfer data temporary storage device 400 and transmitted to the terminal device T1 in the band 100, the buffer overflow becomes a problem, but the data to be transmitted is the text used in the conference. In the case of a data system application such as data, the data does not always be transmitted continuously, but the data flows in a burst. Therefore, if the transfer data temporary storage device 400 has a certain capacity, buffer overflow becomes a problem. Must not.

  The terminal device T2 receives the divided data D30 from the terminal device T1 transmitted from the relay device C1 by the communication unit 101, and transmits it to the combining unit 103 through the receiving unit 102. The synthesizing unit 103 synthesizes the divided data D36 of the received divided data D30 in the order of the division number D35, generates data D40, and passes it to the application 106. The terminal device T3 performs the same operation.

  On the other hand, the relay device C2 receives the divided data D30 from the terminal device T1 transmitted from the relay device C1 by the communication unit 201 and buffers it in the transfer data temporary storage device 400 through the reception unit 202. The communication group control unit 203 that manages the relay destination of the communication group g transfers the data addressed to the communication group g received from the terminal device T1 to the relay device C3 and the terminal device T6 in response to the transmission timing designation unit 204. Specify what to do. For each designated transfer destination, the transmission timing specifying means 204 reads the transfer destination bandwidth storage D50 from the transfer bandwidth storage device 300, and the divided data D30 read from the transfer data temporary storage device 400 is transferred by the transfer bandwidth D50. The transmission timing of each divided data D30 is controlled so that it is transmitted from the communication means 101 in the set transmission band. When a band breakthrough notification is received from the flow rate detecting means 207 during this control, the flow rate is suppressed so that the band breakthrough notification is not issued by expanding the transmission timing. At this time, if there is a plurality of transmission data with different priorities, the transmission timing is expanded in order from the lower priority data so that the higher priority data is transmitted in the designated band. To do. In the case of FIG. 11, the relay device C2 transmits the divided data D30 from the terminal device T1 received in the band 400 to the terminal device T6 through the line L6 with the band 400 and priority 4, and to the relay device C3 the relay line. It transmits with bandwidth 300 and priority 3 through C23.

  The terminal device T6 receives the divided data D30 from the terminal device T1 transmitted from the relay device C2 by the communication unit 101, and transmits it to the combining unit 103 through the receiving unit 102. The synthesizing unit 103 synthesizes the divided data D36 of the received divided data D30 in the order of the division number D35, generates data D40, and passes it to the application 106.

  The relay device C3 receives the divided data D30 transmitted from the terminal device T1 transmitted from the relay device C2 by the communication unit 201 and buffers it in the transfer data temporary storage device 400 through the reception unit 202. The communication group control unit 203 managing the relay destination of the communication group g should transfer the data addressed to the communication group g received from the terminal device T1 to the terminal devices T4 and T5 in response to the transmission timing specifying unit 204. Is specified. For each designated transfer destination, the transmission timing specifying means 204 reads the transfer destination bandwidth storage D50 from the transfer bandwidth storage device 300, and the divided data D30 read from the transfer data temporary storage device 400 is transferred by the transfer bandwidth D50. The transmission timing of each divided data D30 is controlled so that it is transmitted from the communication means 101 in the set transmission band. When a band breakthrough notification is received from the flow rate detecting means 207 during this control, the flow rate is suppressed so that the band breakthrough notification is not issued by expanding the transmission timing. At this time, if there is a plurality of transmission data with different priorities, the transmission timing is expanded in order from the lower priority data so that the higher priority data is transmitted in the designated band. To do. In the case of FIG. 11, the relay device C2 transmits the divided data D30 from the terminal device T1 received in the band 300 to the terminal device T4 with the band 300 and priority 3, and to the terminal device T5 with the band 200 and priority. 2 to send.

  The terminal device T4 receives the divided data D30 from the terminal device T1 transmitted from the relay device C3 by the communication unit 101 and transmits it to the combining unit 103 through the receiving unit 102. The synthesizing unit 103 synthesizes the divided data D36 of the received divided data D30 in the order of the division number D35, generates data D40, and passes it to the application 106. The terminal device T5 performs the same operation as the terminal device T4.

  As described above, data is transmitted from the terminal device T1 to each of the terminal devices T2 to T6 in a transmission band desired by the terminal devices T2 to T6.

  Next, an operation when the terminal device T6 logs out will be described.

  When the application 106 of the terminal device T6 transmits the logout command D10 addressed to the terminal device T1 to the relay device C2 through the communication unit 101, the communication unit 201 of the relay device C2 receives the logout command D10 and communicates through the reception unit 202. At the same time as the transmission to the group control means 203 and the band totalization means 206, the information is relayed to the relay device C1.

  When receiving the logout command D10 of the terminal device T6, the communication group control unit 203 of the relay device C2 excludes the terminal device T6 from the relay target of the own relay device C2 regarding the communication group g. Further, when receiving the logout command D10 of the terminal device T6, the bandwidth totalizing unit 206 deletes the bandwidth command D20 and the bandwidth storage D50 for the terminal device T6 that the terminal device T6 issued regarding the communication group g from the transfer bandwidth storage device 300. To do. As a result, the contents of the transfer band storage device 300 of the relay device C2 change as shown in FIG.

  Further, when the communication unit 201 of the relay device C1 receives the logout command D10 of the terminal device T6 from the relay device C2, the communication unit 201 transmits the logout command D10 to the communication group control unit 203 and the band aggregation unit 206 through the reception unit 202, and at the same time, Relay to device T1.

  When receiving the logout command D10 of the terminal device T6, the communication group control unit 203 of the relay device C1 excludes the terminal device T6 from the relay target of the own relay device C1 with respect to the communication group g. Further, when receiving the logout command D10 of the terminal device T6, the bandwidth totalizing unit 206 deletes the bandwidth command D20 that the terminal device T6 has issued for the communication group g from the transfer bandwidth storage device 300. As a result, the bandwidth command D20 received through the relay device C2 becomes two, that of the terminal device T4 and that of the terminal device T5, and the maximum value is recalculated. As a result, the maximum bandwidth value is 300 and the maximum priority value is 3, so the bandwidth storage D50 for the relay device C2 stored in the transfer bandwidth storage device 300 is updated. As a result, the contents of the transfer band storage device 300 of the relay device C1 change as shown in FIG.

  Upon receiving the logout command D10 from the terminal device T6, the communication unit 101 of the terminal device T1 transmits it to the application 106 and the arbitration unit 105 through the reception unit 102 and the band reception unit 104. When receiving the logout command D10 of the terminal device T6, the application 106 recognizes that the terminal device T6 has logged out from the communication group g. Further, when receiving the logout command D10 of the terminal device T6, the arbitrating means 105 deletes the bandwidth command D20 that the terminal device T6 has issued for the communication group g from the transmission bandwidth storage device 111. Then, the remaining maximum value of the bandwidth command D20 is recalculated. As a result, the maximum bandwidth value is 300 and the maximum priority value is 3, so the maximum transmission bandwidth value of the communication group g stored in the transmission bandwidth storage device 300 is changed to 300 and the priority is changed to 3. . Thereby, the content of the transmission band storage device 111 of the terminal device T1 changes as shown in FIG. Therefore, thereafter, the divided data D30 is transmitted from the terminal device T1 to the terminal devices T2 to T5 with the transmission band 300 and the priority 3.

  Next, the effect of this embodiment will be described.

  According to the present embodiment, it is possible to suppress an increase in the load on the transmitting terminal in a communication system in which a receiving terminal requesting a wide band and a receiving terminal requesting a narrow band are mixed. The reason is that, even if a plurality of receiving side terminal devices request different bands, the transmitting side terminal device only needs to transmit data in the maximum band.

  Further, according to the present embodiment, it is possible to suppress an increase in the load on the network of the relay device in a communication system in which a receiving terminal requesting a wide band and a receiving terminal requesting a narrow band are mixed. The reason is that each relay device only needs to secure a maximum bandwidth among higher-order relay devices even if a plurality of terminal devices under its control request different bandwidths. As a result, even if there are a plurality of receiving terminals having different request bandwidths, data transfer can be performed with a minimum data transfer amount in the network of the relay apparatus.

  Further, according to the present embodiment, in a communication system in which a receiving terminal requesting a wide band and a receiving terminal requesting a narrow band are mixed, data can be received in an optimum band for all receiving terminals. The reason is that when the relay device relays data transmitted from the transmitting terminal to the receiving terminal, the data band is converted to the band of the receiving terminal. As a result, each receiving terminal can provide the user with the maximum quality according to each capability without being influenced by other receiving terminals with low capabilities.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various other additions and modifications can be made. In addition, the relay device and the terminal device of the present invention can be realized by a computer and a program as well as the functions that the relay device and the terminal device have. The program is provided by being recorded on a computer-readable recording medium such as a magnetic disk or a semiconductor memory, and is read by the computer at the time of starting up the computer, etc. Function as a relay device and a terminal device.

  According to the present invention, the data transfer efficiency between relay devices is improved in data-related applications in which data communication is performed in bursts, such as data sharing and whiteboard sharing. Therefore, even if there are a mixture of terminals that require a wide band and terminals that require a narrow band, the application on the sending side can efficiently distribute data by transmitting data in the same band without being conscious of the bandwidth of each partner. Can be performed.

It is a block diagram of the communication system of this invention. It is a block diagram of the terminal device of the present invention. It is a figure which shows formats, such as a login logout command used by this invention, a band command, and divided data. It is a flowchart which shows the process example of the arbitration means in the terminal device of this invention. It is a block diagram of the relay apparatus of this invention. It is a flowchart which shows the process example of the band totaling means in the relay apparatus of this invention. It is operation | movement explanatory drawing of the communication system when the band command is transmitted from the terminal device T2. It is operation | movement explanatory drawing of the communication system when the band command is transmitted from the terminal device T3. It is operation | movement explanatory drawing of the communication system when the band command is transmitted from the terminal device T4. It is operation | movement explanatory drawing of a communication system when the band command is transmitted from terminal device T5. It is operation | movement explanatory drawing of a communication system when the band command is transmitted from terminal device T6. It is operation | movement explanatory drawing of a communication system when the logout command is transmitted from terminal device T6.

Explanation of symbols

T1 to T6 ... terminal devices C1 to C3 ... relay devices L1 to L6 ... lines C12 and C23 ... relay line 100 ... terminal device 101 ... communication means 102 ... receiving means 103 ... combining means 104 ... band receiving means 105 ... arbitration means 106 ... Application 107 ... Division means 108 ... Band setting means 109 ... Transmission timing control means 110 ... Flow rate detection means 111 ... Transmission band storage device 200 ... Relay device 201 ... Communication means 202 ... Reception means 203 ... Communication group control means 204 ... Transmission timing designation Means 205 ... Transmission timing control means 206 ... Band totaling means 207 ... Flow rate detecting means 300 ... Transfer band storage device 400 ... Transfer data temporary storage device

Claims (8)

In a communication method in a communication system in which a plurality of terminal devices are connected to be able to communicate with each other via a plurality of relay devices,
a) a step in which a terminal device on the data receiving side transmits a band command specifying a desired transmission band to a terminal device on the data transmitting side of the same communication group;
b) When the relay device relays the bandwidth command, the received bandwidth command is stored for each communication group in the transfer bandwidth storage device of the own relay device, and the terminal device and other relays connected to the own relay device For each device, calculating the maximum transmission bandwidth of the bandwidth command received from them for each communication group and storing it in the transfer bandwidth storage device;
c) The terminal device on the data transmission side that has received the bandwidth command stores the received bandwidth command in the transmission bandwidth storage device of its own terminal device for each communication group, and sets the maximum transmission bandwidth of the received bandwidth command to the communication group. Calculating each time and storing in the transmission band storage device;
d) The terminal device on the data transmitting side divides the data to be transmitted to the terminal device on the data receiving side of the same communication group into data of a certain length, and each divided data is stored in the maximum transmission bandwidth storage device. Transmitting to the terminal device on the data receiving side of the same communication group in the transmission band; and
e) When the relay device relays the divided data, the received divided data is buffered in a transfer data temporary storage device, and the terminal device connected to the own relay device and each other relay device are connected to the own relay device. Relaying the transfer data with the maximum transmission bandwidth stored in the transfer bandwidth storage device of
and f) a step of receiving the divided data, wherein the terminal device on the data receiving side synthesizes the original data from the divided data.   The bandwidth command includes a priority related to the designated transmission bandwidth, and in step b and step c, the maximum priority is calculated and stored in addition to the maximum transmission bandwidth of the bandwidth command, and the step d 2. The communication method according to claim 1, wherein, in step e, control is performed to reduce a transmission band of data having a lower priority when the communication amount exceeds a predetermined amount.   When the terminal device on the data receiving side logs out from the communication group, the bandwidth command output from the logged out terminal device is transferred to the transfer band storage device of the relay device and the transmission band of the terminal device on the data transmitting side. 2. The communication method according to claim 1, wherein the communication device is deleted from the storage device, and the relay device and the terminal device on the data transmission side recalculate the maximum transmission bandwidth based on the remaining bandwidth command. In the relay device in a communication system in which a plurality of terminal devices are connected to be able to communicate with each other via a plurality of relay devices,
A communication means for communicating with the terminal device and other relay devices in order to relay the data transmitted from the terminal device on the data transmitting side to the terminal device on the data receiving side;
A transfer bandwidth storage device;
A transfer data temporary storage device;
When the communication means relays a band command specifying a transmission band transmitted from the data receiving side terminal apparatus to the data transmitting side terminal apparatus of the same communication group, the band command is communicated to the transfer band storage apparatus. Store for each group, and for each terminal device connected to its own relay device and other relay devices, calculate the maximum transmission bandwidth of the bandwidth command received from them for each communication group and store in the transfer bandwidth storage device Bandwidth summarization means,
Data transmitted from the terminal device on the data transmission side to the terminal device on the data reception side of the same communication group is buffered in the transfer data temporary storage device, and each terminal device connected to the own relay device and other relay devices And a transmission timing control means for relaying the transfer data in the maximum transmission band stored in the transfer band storage device.   The bandwidth command includes a priority related to a designated transmission bandwidth, and the bandwidth aggregation means calculates a maximum priority in addition to the maximum transmission bandwidth of the bandwidth command and stores it in the transfer bandwidth storage device, 5. The relay apparatus according to claim 4, wherein the transmission timing control means performs control to reduce a transmission band of data having a lower priority when the communication amount exceeds a predetermined amount.   When the communication means relays a logout command indicating that the terminal device on the data receiving side has logged out from the communication group, the bandwidth counting means deletes the bandwidth command of the logged out terminal device from the transfer bandwidth storage device. 5. The relay apparatus according to claim 4, wherein the maximum transmission band is recalculated based on the remaining band command. In a communication system in which a plurality of terminal devices are connected to each other via a plurality of relay devices,
The said relay apparatus is a relay apparatus as described in any one of Claims 4-6, The communication system characterized by the above-mentioned. A computer constituting the relay device in a communication system in which a plurality of terminal devices are connected to be able to communicate with each other via a plurality of relay devices, the data transmitted from the terminal device on the data transmission side A computer comprising a communication means for communicating with a terminal device and another relay device for relaying to the terminal device, a transfer band storage device, and a transfer data temporary storage device,
When the communication means relays a band command specifying a transmission band transmitted from the data receiving side terminal apparatus to the data transmitting side terminal apparatus of the same communication group, the band command is communicated to the transfer band storage apparatus. Store for each group, and for each terminal device connected to its own relay device and other relay devices, calculate the maximum transmission bandwidth of the bandwidth command received from them for each communication group and store in the transfer bandwidth storage device Bandwidth summarization means,
Data transmitted from the terminal device on the data transmission side to the terminal device on the data reception side of the same communication group is buffered in the transfer data temporary storage device, and each terminal device connected to the own relay device and other relay devices And a program for functioning as transmission timing control means for relaying transfer data in the maximum transmission band stored in the transfer band storage device.

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