JP4676204B2 - Communication system and communication terminal device - Google Patents

Description

  The present invention relates to a technique effectively applied to an apparatus or method for controlling the flow rate of communication data by bandwidth control or flow control.

Currently, communication devices use an Ethernet (registered trademark) interface (IEEE 802.3) to provide a LAN (Local Area Network) and a WAN (Wide Area Network).
Can be connected seamlessly. A communication device that provides such an Ethernet (registered trademark) interface is equipped with single functions such as bandwidth control and flow control.
JP 2001-217842 A JP 2002-111688 A

  However, conventionally, the linkage and detection functions between these functions are not sufficient, resulting in an adverse effect on the end system.

  For example, a communication apparatus for controlling the network state as described above monitors the congestion state of the network and performs bandwidth control and flow control. However, these controls are uniformly performed for all communications passing through the communication device. For this reason, the conventional communication apparatus cannot perform fine control.

  Further, such control by the conventional communication apparatus is performed only upstream of the network, and is not a mechanism for causing each client terminal downstream to perform control. For example, in Patent Document 1, control is performed only by the communication control device, and control is not performed on the terminal side. Further, in Patent Document 2, although it is possible to perform bandwidth control for each terminal, it is necessary to bother introducing a communication control application individually for each terminal.

  Therefore, in the present invention, the end-to-end communication state is monitored (congestion and the like are detected in advance) and analyzed, and the dynamic management of bandwidth control rate management control and flow control is realized, thereby adversely affecting the end system. An object of the present invention is to provide an apparatus, a method, and the like that can prevent the above-described problem.

  Another object of the present invention is to provide an apparatus, a method, and the like that allow a terminal to perform communication control according to the communication type.

  In order to solve the above problems, the present invention has the following configuration. A first aspect of the present invention is a relay device that relays communication data transmitted from a first terminal device to a second terminal device, and includes relay means, congestion judgment means, and change means. The relay means relays communication data according to the set relay amount. The set relay amount is a relay amount set in advance by the user or the designer when there is no change by the changing means to be described later. Is the relay amount.

The congestion determination means determines whether or not congestion has occurred in the communication path between the first terminal device and the second terminal device for the communication data to be relayed. This determination can be performed by observing the retransmission status, transmission / reception flow rate, response time, etc. of the communication data to be processed.

  The changing unit changes the relay amount according to the congestion state when the congestion determining unit determines that congestion has occurred. The congestion state is a state such as the degree of congestion and whether or not it has been improved.

  According to the relay device configured as described above, the end-to-end communication state between the first terminal device and the second terminal device can be monitored and analyzed, and the dynamic control of the relay amount according to the result Can be realized. For this reason, adverse effects on the end system can be prevented.

  The changing means in the first aspect of the present invention may be configured to change the relay amount for each communication data in accordance with the type and priority of the communication data. With this configuration, it is possible to cope with congestion by reducing the relay amount for other low-priority communication data without reducing the relay amount for high-priority communication data. .

  The changing means in the first aspect of the present invention may be configured to set the relay amount so as to decrease or increase stepwise in accordance with the congestion state. With this configuration, it becomes possible to deal with a congestion situation more flexibly. Therefore, congestion can be improved without wastefully reducing the relay amount.

  In the first aspect of the present invention, when it is determined that congestion is occurring by the congestion determination means, data for instructing to adjust the transmission amount of communication data according to the congestion state is Instruction data transmission means for transmitting to the terminal device may be further provided. With this configuration, the terminal device can be made to perform communication control. Accordingly, it is possible to adjust the transmission amount of communication data on the source side (communication data transmission source), and it is possible to improve congestion more effectively.

  According to a second aspect of the present invention, a receiving unit that receives data including an instruction for adjusting a transmission amount of communication data and a physical port to be adjusted are specified from information included in the received data. It is a communication terminal apparatus that includes a specifying unit and an adjusting unit that adjusts the data transmission amount only for the specified physical port. Such a second aspect of the present invention can control congestion by receiving the above instruction data from the first aspect of the present invention.

  The first aspect and the second aspect may be realized by executing the program by the information processing apparatus. That is, the present invention specifies the processing executed by each unit in the first aspect and the second aspect described above as a program for causing the information processing apparatus to execute or a recording medium on which the program is recorded. Can do. Further, the present invention may be specified by a method in which the information processing apparatus executes the processing executed by each of the above-described means.

  According to the present invention, the end-to-end communication state is monitored (congestion and the like are detected in advance) and analyzed, and the dynamic effect of bandwidth control rate management control and flow control is realized, thereby adversely affecting the end system. Can be prevented.

First, a network configuration example to which the communication devices 1 and 3 according to the present invention are applied will be described. FIG. 1 is a diagram illustrating a network configuration example to which the communication devices 1 and 3 are applied. In FIG. 1, a client-side network and a server-side network configured as a LAN are connected to a carrier network configured as a WAN using an Ethernet (registered trademark) interface. The carrier network is configured using a plurality of carrier devices 5 such as an ATM (Asynchronous Transfer Mode) device or an IP router.

  The client-side network includes a communication device 1 according to the present invention and one or a plurality of client devices 2 connected to the communication device 1. Each client device 2 is connected to the communication device 1 by a LAN device such as a HUB as necessary. Further, there may be one or more client side networks connected to the carrier network.

  The server-side network is composed of the communication device 3 according to the present invention and one or a plurality of server devices 4 connected to the communication device 3. Each server device 4 is connected to the communication device 3 by a LAN device such as a HUB as necessary. Further, the server side network connected to the carrier network may be one or plural. Communication between a plurality of client-side networks may be used.

〔Communication device〕
Next, the communication devices 1 and 3 will be described. In the following description, the configuration of the client-side network will be described as an example, and thus the communication device 1 will be described. However, the communication device 1 and the communication device 3 are basically the same in configuration. That is, the communication device 1 and the communication device 3 have basically the same configuration except that they are connected to the client side network and the server side network.

FIG. 2 is a diagram illustrating a configuration example of a client-side network. Hereinafter, the communication apparatus 1 will be described with reference to FIG. The communication device 1 includes a CPU (central processing unit), a main storage device (RAM), an auxiliary storage device, and the like connected via a bus in terms of hardware. The auxiliary storage device is configured using a nonvolatile storage device. The non-volatile storage device referred to here is a so-called ROM (Read-Only Memory: EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory),
(Including mask ROM), FRAM (Ferroelectric RAM), hard disk and the like.
The communication device 1 loads various programs (OS, applications, etc.) stored in the auxiliary storage device into the main storage device and is executed by the CPU, whereby the control target extraction unit 11, the communication state analysis unit 12, the rate management It functions as a device including the unit 13, the Pause frame output unit 14, the shaping unit 15, the DB 16, and the like. Each of these functional units except the DB 16 is realized by executing a program by the CPU. Further, each of these functional units excluding the DB 16 may be configured as a dedicated chip. Next, each functional unit included in the communication device 1 will be described.

[Control object extraction unit]
The control target extraction unit 11 extracts only communication of a specific communication type based on the Config information. FIG. 3 is a flowchart illustrating an operation example of the control target extraction unit 11. The control target extraction unit 11 first reads Config information (S01). The Config information is stored in advance in a nonvolatile storage device (not shown). The Config information is information such as VLAN (Virtual LAN) and bandwidth control setting, for example, and is information set in advance by a user or the like. Next, the control target extraction unit 11 reads out various tables (S02). The various tables are tables that the communication device holds from the time of the prior art, such as a route information table. The various tables read by the control target extraction unit 11 are different from the various tables stored in the DB 16 described below. Then, the control target extraction unit 11 creates a control target DB based on the read Config information and various table information (S03). The control target DB is stored in the DB 16.

[Communication state analysis section]
The communication state analysis unit 12 monitors and analyzes the state of a session and the amount of communication for data of a specific communication type (communication data to be subjected to bandwidth / flow control). FIG. 4 is a flowchart illustrating an operation example of the communication state analysis unit 12. First, the communication state analysis unit 12 reads the control target DB from the DB 16 (S04). Next, the communication state analysis unit 12 determines the protocol of communication data that is processed by the communication device 1 (S05). This determination can be realized, for example, by reading header information of communication data to be processed.

When the protocol is TCP (Transmission Control Protocol) (S05-TCP
), The communication state analysis unit 12 selects a representative session (S06). The communication state analysis unit 12 selects a representative session based on the priority of each communication preset in the Config information. Further, the communication state analysis unit 12 may select a representative session for each port number. Next, the communication state analysis unit 12 updates the session state for the representative session (S07). Specifically, the communication state analysis unit 12 updates the TCP session information table stored in the DB 16 by detecting the retransmission status and monitoring the window size. Next, the communication state analysis unit 12 determines the end of the session. In the case of continuation (S08-continuation), the communication state analysis unit 12 repeats the process of S07. If the session is ended (S08-end), the process ends.

When the protocol is ICMP (Internet Control Message Protocol) (S05-
ICMP), the communication state analysis unit 12 updates the ICMP response information (S09). Specifically, the information in the ICMP information table stored in the DB 16 is updated.

  When the protocol is UDP (User Datagram Protocol) (S05-UDP), the communication state analysis unit 12 selects a representative flow (S10). For example, the communication state analysis unit 12 may select a representative flow for each port number. Next, the communication state analysis unit 12 updates the session state for the representative flow (S11). Specifically, the communication state analysis unit 12 updates the UDP information table stored in the DB 16 by measuring the transmission / reception flow rate. Next, the communication state analysis unit 12 determines the end of the session. In the case of continuation (S12-continuation), the communication state analysis unit 12 repeats the process of S11. If the session is ended (S12-End), the process ends.

  Since the processing of the communication state analysis unit 12 performs control only on data of a specific communication type in this way, for example, even when congestion occurs, only the communication band other than important communication is controlled. It becomes possible. That is, when congestion occurs, it is possible to cope with important communication only by bandwidth control for other unimportant communications without performing bandwidth control. For this reason, a bandwidth is secured for important communications, and adverse effects can be prevented.

[Rate Management Department]
The rate management unit 13 sets and updates the value of the Shaping rate included in the Config information when it is determined that the communication state analysis unit 12 is in a congested state as a result of the analysis. To control. FIG. 5 is a flowchart illustrating an operation example of the rate management unit 13. The rate management unit 13 first reads the bandwidth control information table from the DB 16 (S13). Next, the rate management unit 13 performs aggregation for each processing target unit of shaping (S14). Next, the rate management unit 13 determines whether congestion has occurred between end systems (S15). If the rate management unit 13 determines that no congestion occurs (S15—no congestion), the rate management unit 13 ends the process.

On the other hand, when the rate management unit 13 determines that congestion has occurred (S15—congestion detection / continuation), the rate management unit 13 determines whether or not the congestion state has been improved as compared to the congestion state thus far ( S16). When this determination is the first time or when it is determined that it has not improved (S16—first time / continuation), the rate management unit 13 determines the degree of congestion (S17). Then, the rate management unit 13 decreases the shaping rate according to the situation (S18, S19). Specifically, the rate management unit 13 significantly reduces the shaping rate when the congestion situation is severe (S18), and reduces the shaping rate with a smaller reduction amount than the former case when the congestion situation is mild. (S19). At this time, the rate management unit 13 also rewrites the suppression rate value in the bandwidth control information table stored in the DB 16. At this time, the rate management unit 13 may be configured to set a different shaping rate for each control target.

  When the rate management unit 13 determines that the congestion state has been improved (S16—improvement), the rate management unit 13 determines the degree of improvement. When it is determined that the recovery has been completed (S22—complete recovery), the rate management unit 13 completely restores the shaping rate (that is, restores the initial value of the shaping rate: S24). On the other hand, in other cases (S16—others), the rate management unit 13 restores the shaping rate at a constant rate (S23). In this case, for example, the rate management unit 13 may be configured to recover by increasing the shaping rate by 1/10 by a fixed period. At this time, the rate management unit 13 also rewrites the suppression rate value in the bandwidth control information table stored in the DB 16.

  When the rate management unit 13 determines the setting of the shaping rate according to the processing of S18, S19, S23, and S24, the contents are reflected in the DB 16 and the change is reflected (S20). At this time, the rate management unit 13 may be configured to transmit the shaping rate to the shaping unit 15 to change the setting. Then, the rate management unit 13 informs the pause frame output unit 14 to execute pause frame output processing (S21).

[Pause frame output unit]
The Pause frame output unit 14 causes the client device 2 to perform flow control on the physical port to be controlled when it is determined as a result of analysis by the communication state analysis unit 12 that the client device 2 is in a congested state. A frame is generated and sent to the client device 2. At this time, the extended Pause frame includes information for specifying a physical port to be controlled.

  FIG. 6 is a flowchart illustrating an operation example of the Pause frame output unit 14. The Pause frame output unit 14 reads information on the communication and output port to be processed from the control target DB stored in the DB 16 (S25). Then, the Pause frame output unit 14 generates and outputs an extended Pause frame based on the read information (S26, S27). FIG. 7 is a diagram illustrating a configuration example of an extended pause frame. FIG. 7A shows the configuration of an 802.3X standard Pause frame, and FIG. 7B shows an example of an extended Pause frame. An extended Pause frame is different from a standard Pause frame in that it has an extension code, a protocol number, a source IP address, a source port number, a destination IP address, a destination port number, and a VLAN tag. Data peculiar to these extended Pause frames is added to a portion corresponding to padding of a standard Pause frame. The extension code includes information used for identifying an extended Pause frame. As this value, in order to distinguish from the padding of the standard frame, a Hash value from the preamble to the relay time is given. The transmission source IP address, transmission source port number, destination IP address, and destination port number respectively have the transmission source, destination IP address, and port number of the communication to be processed. The above port number is used only in the case of TCP or UDP. The VLAN tag is a tag (VLAN ID) for identifying a VLAN to be processed.

  The extended pause frame has the same frame length as that of the standard pause frame, so that compatibility is maintained. For this reason, even when the client apparatus 2 in which the application for recognizing the extended Pause frame is not installed receives the extended Pause frame, it is interpreted as a standard Pause frame. Therefore, Pause processing can be continued even in a system including the conventional client apparatus 2 by such an extension of the Pause frame. The protocol number is information for identifying a protocol such as TCP or UDP.

  Thus, by generating and outputting the extended Pause frame, the client device 2 (terminal side) can perform control for a specific physical port. Therefore, the control by the communication device 1 and the control by the client device 2 can be linked, and as a result, the network can be controlled effectively.

[Shaping section]
The shaping unit 15 adjusts the flow rate at which communication data flowing from the LAN side flows out to the carrier network side (so-called shaping). At this time, the shaping unit 15 performs shaping according to the shaping rate set and updated by the rate management unit 13.

[DB]
The DB 16 is configured using a nonvolatile storage device. The DB 16 creates a control target DB. Specifically, the DB 16 stores a control target DB including a bandwidth control information table, a VLAN information table, an IP address information table, a buffering information table, a TCP session information table, a UDP information table, an ICMP information table, and the like. FIG. 8 is a diagram illustrating examples of various tables stored in the DB 16. The control ID is information common to each table, that is, information serving as a primary key. The bandwidth control method indicates a classification method. The setting shaping rate indicates an initial value of the shaping rate set in the config information. The suppression rate is a value for calculating the current shaping rate, and indicates a ratio for changing the set shaping rate to the current shaping rate. For example, when the set shaping rate is 100k and the suppression rate is 90%, the current shaping rate is 90k. The current shaping rate indicates the current shaping rate, and the immediately preceding shaping rate indicates the shaping rate in the processing result by the previous rate management unit 13. As described above, by recording the immediately preceding shaping rate, it is possible to determine whether or not congestion is detected for the first time in the processing of S16 of the rate management unit 13. The physical port number in the VLAN information table may have a plurality of values. The measurement time in the buffering information table indicates the time when the measurement was last performed. Also, the response time in the TCP session information table is expressed using the time until Ack returns. Based on this information, it is possible to determine the occurrence of congestion and its precursor. The response time in the ICMP information table is expressed using the time until the echo returns. Also, the sequence number in the TCP session information table. Is expressed using the serial number of the packet. Each other value in each table indicates a value as shown in the name in FIG.

[Client device]
The client device 2 includes a CPU, a main storage device, an auxiliary storage device, and the like connected via a bus in terms of hardware. The auxiliary storage device is configured using a nonvolatile storage device. The nonvolatile storage device here refers to a so-called ROM, hard disk, or the like. The client device 2 loads various programs (OS, application, extended Pause control program, etc.) stored in the auxiliary storage device into the main storage device and executes them by the CPU, thereby responding to the standard Pause frame and the extended Pause frame. It functions as a device that can perform the processing. The client device 2 is configured as a general information processing terminal except for a configuration that can perform processing according to the extended Pause frame.

The client device 2 also includes a LAN device such as a HUB or a switch. When a LAN device that supports this method receives an extended Pause frame, the physical port that is the target of flow control is determined from the extended information, and the extended Pause frame is transmitted from the target port. As a result, extended flow control for the client device 2 at the end is further performed.

  When the client apparatus 2 receives the standard Pause frame or the extended Pause frame, the client apparatus 2 performs processing according to the received frame. However, in order to perform processing corresponding to the extended Pause frame, the client device 2 needs to be installed and operable so that the extended Pause control program is installed. Hereinafter, the processing of the client apparatus 2 in which the extended Pause control program is installed, particularly processing according to the extended Pause frame will be described.

When the client apparatus 2 receives the extended Pause frame, the client apparatus 2 performs flow control on the physical port indicated in this frame. FIG. 9 is a flowchart illustrating an operation example of the client apparatus 2. Upon receiving the Pause frame (S28), the client device 2 determines whether the received Pause frame is a standard Pause frame or an extended Pause frame (S29). When the received Pause frame is an extended Pause frame (S29-expansion), the client device 2 analyzes the contents of the extended frame (S30), and determines a physical port to be processed (S31). At this time, the client device 2 determines a target physical port by referring to an ARP (Address Resolution Protocol) table (not shown). Then, flow control is performed on the physical port according to the contents of the extended Pause frame (S32).

On the other hand, when the received Pause frame is a standard frame (S29-standard), the client device 2 analyzes the content of the standard frame (S33), and performs flow control conforming to 802.3x according to the content (S34). ). If the extended Pause control program is not installed in the client device 2, the processing of S33 and S34 is executed by the client device 2 without performing the processing of S29. As described above, since the extended Pause frame is an extension of the contents of the standard frame, flow control according to the standard Pause frame is performed even when there is a client device 2 in which the extended Pause control program is not installed. It becomes possible. Further, according to the client device 2 in which the extended Pause control program is installed, flow control for a specific physical port can be realized. Similarly, the communication devices 1 and 3 realize processing for the extended Pause frame.

[Modification]
Each functional unit and DB 16 included in the communication devices 1 and 3 may be mounted on the carrier device 5. In this case, it is desirable that the carrier devices 5 installed in the carrier network be mounted on the carrier device 5 installed at a position closest to the client side network or the server side network.

[Others]
The present invention can be specified as follows.
(Appendix 1) A relay device that relays communication data transmitted from a first terminal device to a second terminal device,
Relay means for relaying the communication data according to a set relay amount;
Congestion determination means for determining whether or not congestion has occurred in the communication path between the first terminal device and the second terminal device for communication data to be relayed;
A relay apparatus comprising: a changing unit that changes the relay amount according to a congestion state when it is determined by the congestion determining unit that congestion has occurred.
(Additional remark 2) The said change means is a relay apparatus of Additional remark 1 which changes the said relay amount for every communication data according to the classification and priority of the said communication data.
(Additional remark 3) The said change means is a relay apparatus of Additional remark 1 or 2 which sets so that the said relay amount may be decreased or increased in steps according to the condition of congestion.
(Additional remark 4) When the said change means judges that the congestion condition has improved, it changes so that the said relay amount may be increased, and when it judges that the congestion condition has not improved, it will change the said relay amount. The relay device according to any one of appendices 1 to 3, which is changed so as to decrease.
(Additional remark 5) When it is judged that the congestion has arisen by the said congestion judgment means, according to the condition of congestion, the data which instruct | indicates adjusting the transmission amount of the said communication data are set to said 1st terminal device 5. The relay device according to any one of appendices 1 to 4, further comprising instruction data transmission means for transmitting to the network.
(Additional remark 6) The said instruction data transmission means is a relay apparatus of Additional remark 5 which expands and transmits the Pause frame compatible with IEEE802.3x.
(Supplementary Note 7) Receiving means for receiving data including an instruction for adjusting the transmission amount of communication data;
A specifying means for specifying a physical port to be adjusted from information included in the received data;
A communication terminal apparatus including adjustment means for adjusting a data transmission amount only for the identified physical port.
(Supplementary Note 8) The adjustment unit determines whether the received Pause frame is a standard Pause frame or an extended Pause frame. If the received Pause frame is a standard Pause frame, the adjustment unit executes flow control conforming to IEEE 802.3x. 8. The communication terminal device according to 7.
(Supplementary Note 9) A relay method performed by an information processing device that relays communication data transmitted from a first terminal device to a second terminal device,
The information processing apparatus determines whether or not congestion has occurred in a communication path between the first terminal apparatus and the second terminal apparatus for communication data to be relayed;
When the information processing apparatus determines that congestion has occurred, changing the relay amount according to the congestion state;
The information processing apparatus relaying the communication data according to a set relay amount.
(Additional remark 10) The information processing apparatus which transmits communication data receives the data containing the instruction | indication about adjusting the transmission amount of communication data,
The information processing apparatus specifies a physical port to be adjusted from information included in the received data;
The information processing apparatus includes a step of adjusting a data transmission amount only for the specified physical port.
(Supplementary Note 11) For an information processing device that relays communication data transmitted from a first terminal device to a second terminal device,
Determining whether or not congestion has occurred in the communication path between the first terminal device and the second terminal device for communication data to be relayed;
When it is determined that congestion has occurred, changing the relay amount according to the congestion status;
A program for executing the step of relaying the communication data according to a set relay amount.
(Supplementary Note 12) For an information processing apparatus that transmits communication data,
Receiving data including instructions for adjusting the amount of communication data to be transmitted;
Identifying a physical port to be adjusted from information included in the received data;
And a step of adjusting the data transmission amount only for the specified physical port.

It is a figure which shows the structural example of the network with which the communication apparatus by this invention is applied. It is a figure which shows the structural example of a client side network. It is a flowchart which shows the operation example of a control object extraction part. It is a flowchart which shows the operation example of a communication state analysis part. It is a flowchart which shows the operation example of a rate management part. It is a flowchart which shows the operation example of a Pause frame output part. It is a figure which shows the structural example of an extended Pause frame. It is a figure which shows the example of the various tables which DB memorize | stores. It is a flowchart which shows the operation example of a client apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Communication apparatus 2 Client apparatus 3 Communication apparatus 4 Server apparatus 5 Carrier apparatus 11 Control object extraction part 12 Communication state analysis part 13 Rate management part 14 Pause frame output part 15 Shaping part 16 DB

Claims (4)

A communication system including a relay device that relays communication data transmitted from a first terminal device to a second terminal device and the first terminal device,
The relay device is
Relay means for relaying the communication data according to a set relay amount;
Congestion determination means for determining whether or not congestion has occurred in the communication path between the first terminal device and the second terminal device for communication data to be relayed;
A change unit that changes the relay amount according to a congestion state when it is determined by the congestion determination unit that congestion has occurred;
When it is determined by the congestion determination means that congestion has occurred, it includes information for specifying a port to be adjusted according to the congestion state, and instructs to adjust the transmission amount of the communication data An extended pause frame including data , wherein the extended pause frame includes at least an extension code, a protocol number, a source IP address, a source port number, a destination IP address, and a destination port number in the padding area of the standard pause frame. ,
Instruction data transmission means for transmitting to the first terminal device,
The first terminal device is:
Receiving means for receiving the extended pause frame transmitted from the instruction data transmitting means;
A specifying unit for specifying a port to be adjusted based on information for specifying a port to be adjusted included in the extended pause frame received by the receiving unit;
A communication system including adjustment means for adjusting a data transmission amount only for the port specified by the specifying means; The communication system according to claim 1, wherein the data instructing adjustment of the transmission amount of the communication data includes an address of the first terminal device. The change means changes the relay amount to increase when it is determined that the congestion situation has improved, and decreases the relay amount when it is determined that the congestion state has not improved. The communication system according to claim 1 or 2 to be changed. A communication terminal device that communicates with a communication partner via a relay device,
When it is determined by the congestion determination means provided in the relay device that congestion has occurred in the communication path between the communication terminal device and the communication partner, the port to be adjusted is identified according to the congestion state And an extended pause frame that is data for instructing adjustment of the transmission amount of communication data in the communication terminal device, and includes an extension code, a protocol number, and a source IP address in the padding area of the standard pause frame , The extended pause flag that stores at least the source port number, destination IP address, and destination port number
Receiving means for receiving a frame from the relay device;
A specifying unit for specifying a physical port to be adjusted based on information for specifying a port to be adjusted included in the extended pause frame received by the receiving unit;
A communication terminal device including adjustment means for adjusting a data transmission amount only for the physical port specified by the specifying means;

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