JP2011176693A - Mobile radio communication apparatus, tcp flow control device and method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform traffic control of data (downlink) received from a base station, in particular, to dynamically control a TCP (Transmission Control Protocol) flow of non-preferential traffic. <P>SOLUTION: A TCP flow control device 1 provided in a mobile 20 which performs radio communication with a base station 4 and performs TCP communication with an IP communication apparatus (CN) 7 on a network 6 via the base station 4. A TCP link monitor 12 monitors the flows of a plurality of TCP links to be used for TCP communication between the IP communication apparatus (CN) 7 on the network 6 and an IP communication apparatus (MN) 2 provided in the mobile 20 and measures traffic volume for each TCP link. A TCP flow control part 13 specifies each TCP link in the plurality of TCP links to either a preferential traffic TCP link or a non-preferential traffic TCP link, and when a ratio of preferential traffic volume to total traffic volume exceeds a predetermined threshold, suppresses the traffic volume of the non-preferential traffic TCP links. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a method for controlling TCP (Transmission Control Protocol) throughput.

With the spread of the Internet, Internet access from homes and companies is becoming common. Most of the current Internet access is browsing of the Web by HTTP (HyperText Transfer Protocol).
HTTP is a communication protocol using TCP / IP. Most of the current Internet access uses the TCP / IP protocol.

Next, an outline of the operation of TCP / IP will be described. TCP has a sequence number for the purpose of realizing reliable communication and detects packet loss, duplication, reordering, and retransmission control, and has an acknowledgment (ACK) mechanism using the sequence number. . When the receiving terminal receives the TCP data packet, it returns an ACK packet as an acknowledgment to the transmission server. A sequence number is described in the ACK packet and the TCP data packet.

The sequence number of the TCP data packet represents how far the data transmitted or received by TCP is transmitted or received, and is used to detect packet duplication and order change. The sequence number of the ACK packet represents which TCP data packet the receiving terminal expects to receive next. If a loss occurs in a certain TCP data packet and the next TCP data packet can be received, the receiving terminal may refer to the sequence number of the TCP data packet to cause a loss in the TCP data packet. I know that there is. At that time, the sequence number of the TCP data packet expected to be received next is described in the ACK packet returned by the receiving terminal.

TCP performs communication while confirming transmission / reception between a transmission server and a reception terminal. However, when communication is performed after waiting for a confirmation response for each packet, communication performance deteriorates when a round trip time (RTT) is increased. Become. In order to avoid such a problem, TCP has a function of transmitting a plurality of packets at a time without waiting for an ACK. The number of packets transmitted at a time is determined by the congestion window size and the receivable window size.

The congestion window size is defined in order to avoid a packet loss exceeding the network capacity by suddenly sending a large number of packets in a network whose bandwidth is unknown. This value is incremented every time an ACK packet is received with an initial value of one segment (one packet).
The receivable window size represents the amount of data that can be received by the receiving terminal at one time, and is defined so that the transmission server does not transmit TCP data packets that cannot be received by the receiving terminal at one time.

In TCP, the transmission server selects the smaller of the congestion window size and the receivable window size at that time, and sends the packet with the selected value as the upper limit so that the communication performance does not deteriorate even if the RTT becomes long. Control the amount of packets to send.

In addition, in a network whose bandwidth is unknown to TCP, a large amount of packets are suddenly transmitted to prevent packet loss, and in order to achieve maximum throughput efficiently, slow start, congestion avoidance, Fast Retransmit It has a function. The slow start algorithm and the congestion avoidance algorithm control the congestion window size.

First, the congestion window size increases exponentially until the congestion window size reaches the slow start threshold. The reason why the congestion window size is increased exponentially is that the slow start threshold is set as a threshold for the amount of data that has a relatively low risk of loss even if it is transmitted at one time. While the value is below this threshold, the congestion window size is rapidly increased. This is called the slow start phase.

When the congestion window size exceeds the slow start threshold, the increase in the congestion window size that has increased exponentially changes to a linear increase. The congestion window size is increased linearly because it is judged that the congestion window size has exceeded the slow start threshold and the risk of loss has increased, and while the congestion window size exceeds this value, the congestion window size increases slowly. Increase the congestion window size. This is called a congestion avoidance phase.

When packet loss is detected, the slow start threshold is set to half of the smaller one of the congestion window size and the receivable window size at that time, the congestion window size is reset to the initial value, and the flow proceeds to the slow start phase. .

The Fast Retransmit algorithm is an algorithm that, when three ACK packets having the same sequence number arrive in duplicate (duplication confirmation response), determines that a packet loss has occurred and retransmits the packet without waiting for a retransmission timeout. . At this time, the congestion window size is returned to the initial value.

In recent years, wireless Internet access represented by Web access using a mobile phone has made significant progress. 2. Description of the Related Art Internet connection services using adapters that connect to mobile phone packet communication networks have been developed for devices other than mobile phones, such as notebook computers and PDAs. In addition, Internet connection services such as notebook personal computers and PDAs in wireless LAN hotspots have been developed, and Internet connection in an outdoor mobile environment is becoming common.

There is also an Internet access service using a communication satellite. In this service, the RTT becomes long in a network with a high delay such as a satellite line. For this reason, the problem that the throughput performance of TCP does not improve occurs. In the case where performance is affected by such TCP characteristics, there is a technique for improving TCP throughput by placing a TCP Proxy device between TCP links. The TCP Proxy device is installed between lines with a large RTT, and is a device that reduces the apparent RTT and increases the TCP throughput by transmitting the TCP ACK inside the TCP Proxy before receiving it from the wireless network.

There is also a device that realizes bandwidth control of TCP traffic on a fixed line. This bandwidth control device is installed as a gateway of the network on the terminal side of the fixed line, and performs TCP window size control and ACK division control with a constant line transmission rate, thereby reducing the TCP bandwidth of the downlink on the terminal side. It is a device to control.

"Controlling WAN Bandwidth and Application Traffic", published by PACKETER "Connection division mechanism TCP-gSTAR suitable for high-speed satellite Internet", IEICE Transactions B, Vol. J91-B, no. 12, pp. 1587-1599, 2008.

Although there is a technology that implements a TCP proxy function or a partial termination function in the middle of a TCP communication link, it is a technology that is used in a stable state of a communication link such as wired communication or satellite line. For example, when a mobile phone packet communication network is connected to a moving body such as a car, train, bus, etc., the conventional technology causes a loss or delay of TCP packets due to fluctuations in the radio band, which in turn degrades the performance. was there. In addition, there is a problem in that it is impossible to follow a communication band that changes with movement or radio conditions.
The present invention solves such a problem, and an object of the present invention is to control traffic of data (downlink) received from a base station, particularly to dynamically control a TCP flow of non-priority traffic.

In the present invention, a mobile radio communication device performs radio communication with a base station, and performs mobile communication with an IP communication device on a network via the base station.
A TCP link monitoring unit that monitors a flow of a plurality of TCP links used for the TCP communication and measures a traffic amount for each of the TCP links, a TCP link for priority traffic, and a non-priority TCP link among the plurality of TCP links A TCP flow control unit that identifies one of the traffic TCP links and controls the traffic amount of the non-priority traffic TCP link according to the traffic amount of the priority traffic TCP link.

  The TCP flow control apparatus according to the present invention is a TCP flow control provided in a mobile radio communication apparatus that performs radio communication with a base station and performs TCP communication with an IP communication apparatus on a network via the base station. In the apparatus, the flow of a plurality of TCP links used for TCP communication between the IP communication apparatus on the network and the IP communication apparatus provided in the mobile radio communication apparatus is monitored, and the traffic amount for each TCP link is determined. The TCP link monitoring unit to be measured and each TCP link in the plurality of TCP links is identified as either a TCP link for priority traffic or a TCP link for non-priority traffic, and according to the traffic volume of the TCP link for priority traffic TCP flow for controlling the traffic amount of the TCP link for non-priority traffic And a control unit.

  Further, the TCP flow control method according to the present invention is a mobile radio communication apparatus or mobile radio communication apparatus that performs radio communication with a base station and performs TCP communication with an IP communication apparatus on a network via the base station. A TCP flow control method executed in an IP communication apparatus connected to the network, wherein a plurality of TCP link flows used for the TCP communication are monitored and a traffic step for each TCP link is measured; Each TCP link in the TCP link is identified as either a TCP link for priority traffic or a TCP link for non-priority traffic, and according to the traffic amount of the TCP link for priority traffic measured in the measurement step, TCP flow that suppresses traffic volume of TCP link for non-priority traffic And a control step.

Since it is configured as described above, the bandwidth of the non-priority traffic TCP link is suppressed by the receivable window size control or ACK control, and as a result, the communication bandwidth of the priority traffic is expanded and the priority traffic throughput is increased. Can be improved.
In addition, since priority traffic is constantly monitored, it is possible to recognize the data volume of priority traffic and non-priority traffic, and reduce the amount of control of non-priority traffic when sufficient bandwidth is secured. Or when it is identified that priority traffic is not temporarily flowing, it is possible to temporarily allocate a free communication band to non-priority traffic to realize efficient communication.

1 is an overall configuration diagram of a network according to Embodiment 1. FIG. 1 is an internal configuration diagram of a mobile router 1. FIG. It is a sequence diagram explaining control operation | movement of a TCP flow. 6 is an operation explanatory diagram of the RF link monitor 10. FIG. 6 is an operation explanatory diagram of the flow control monitor 11. FIG. 3 is a flowchart showing the operation of the flow control monitor 11. 4 is a flowchart showing the operation of a TCP flow control unit 13.

The best mode for carrying out the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. Components having the same functions are denoted by the same reference symbols throughout the drawings described in the embodiments, and the repetitive description thereof is omitted.

Embodiment 1.
FIG. 1 shows the overall configuration of a network including the Internet.
The mobile device 20 includes a mobile router 1, an IP communication device 2 as a mobile node (MN), and a wireless device (RF) 3. The mobile router 1 constitutes a local network 21 in a mobile device, and an IP communication device (MN) 2 is connected to the local network 21. FIG. 1 shows an example in which two IP communication devices 2a and 2b are connected.

  The mobile router 1 is connected to a wireless device 3, connected to the Internet 6 via a wireless base station (BS) 4 and a wireless IP network 5, and an IP communication device 7 as a correspondent node (CN) is provided on the Internet. Exists. FIG. 1 shows a case where two IP communication devices 7a and 7b exist.

Next, the data flow will be described. The IP communication device (MN) 2 in the mobile device 20 performs TCP communication with the IP communication device (CN) 7 on the Internet 6. If normal Web access is replaced with an example, the IP communication device (MN) 2 corresponds to a personal computer, and the IP communication device (CN) 7 corresponds to a Web server.

The IP communication device (MN) 2 establishes a plurality of TCP links with the IP communication device (CN) 7 to perform communication. Among the plurality of TCP links, there are TCP links for high priority traffic (priority traffic) and TCP links for low priority traffic (non-priority traffic). For example, it is possible to classify control-related communication requiring constant transmission / reception as high-priority traffic and classify entertainment-related media communication by web access as low-priority traffic.

The configuration of the mechanism for managing and controlling the TCP flow inside the mobile router 1 is shown in the block diagram of FIG. The TCP data is transmitted and received between the IP communication device (CN) 7 and the IP communication device (MN) 2 on the Internet 6 via the wireless device (RF module) 3. A portion surrounded by a dotted line in FIG. 2 is a TCP flow control device that manages and controls a TCP flow. This TCP flow control device is installed in the mobile router 1 on the mobile device 20 side, and is not mounted on the IP communication device (CN) 7 corresponding to the Web server.
In the present embodiment, data (downlink) traffic received by a mobile station from a base station is controlled. In particular, control for suppressing low priority traffic will be described.

The TCP flow management mechanism includes a TCP link monitor 12 that monitors the status of each TCP link among a plurality of TCP links to be used and obtains information on each TCP link, and an RF that obtains radio link information from the radio apparatus 3. The information obtained from the link monitor 10, the TCP link monitor 12 and the RF link monitor 10 is processed and output from the flow control monitor 11 and the flow control monitor 11 which output parameters necessary for determining the contents of the TCP flow control. The TCP flow control unit 13 controls the TCP flow based on the information.

Next, the operation will be described.
FIG. 3 is a sequence diagram for explaining the operation of the mechanism for managing and controlling the TCP flow. The upper block in the figure corresponds to each block in FIG.

  The wireless device 3 is connected to the wireless base station 4 at the wireless layer. The wireless device 3 monitors the wireless state and changes the wireless communication state as necessary. The contents of the wireless communication state change vary depending on the wireless system of the wireless device. For example, in the case of a 3G mobile phone network, the communication rate is changed according to the state of the radio resources of the radio base station. For example, in the case of a wireless LAN, the communication rate is changed by changing the modulation method according to the strength of the radio wave. With this change, the communicable bandwidth varies.

In the lower layer of the radio layer, the modulation method change information and the transmission rate with the base station are obtained, converted into a communication rate, and held as RF link information. Further, the communication quality can be estimated from the antenna picture for a 3G mobile phone and the radio wave intensity for a wireless LAN without using the control of the lower layer of the wireless layer. The RF link information obtained by these methods is held inside the wireless device 3. In this embodiment, as RF link information, for example, received signal strength information (RSSI: Received Signal Strength Indication) and reception sensitivity information are used.

The RF link monitor 10 makes an inquiry about the wireless state to the wireless device 3 at regular intervals (S1). The wireless device 3 notifies the RF link information indicating the wireless state at the time of inquiry (S2). If the RF link information to be notified can be obtained from a lower layer of the radio layer as described above, more detailed information can be obtained.

  The obtained RF link information is processed by the RF link monitor 10 and notified to the flow control monitor 11 (S3). The reason why the information is processed by the RF link monitor 10 is to abstract the information because it is not necessary to directly notify the flow control monitor 11 of the detailed information of the radio layer. For example, RSSI and reception sensitivity information are shown in 1 to 5 levels and output as RF link information. As another example, the wireless quality may be shown in three stages of high / medium / low, and the connection state may be abstracted in two stages of wireless connection / wireless disconnection.

  While communication (S4) using TCP is being performed between the IP communication device (MN) 2 and the IP communication device (CN) 7, the TCP link monitor 12 constantly monitors the state of the TCP link (S5). . Specifically, the TCP link monitor 12 measures the number of transmitted / received bytes for each TCP link, identifies whether each TCP link is for priority traffic or non-priority traffic, measures the number of lost packets for each TCP link, and performs RTT measurement. carry out. Then, the collected information is notified to the flow control monitor 11 as TCP link state information at regular intervals (S6). The TCP link state information includes, for example, total traffic amount, packet loss amount, RTT, identification information indicating whether the TCP link is for priority traffic or non-priority traffic, and the like. The TCP link monitor 12 notifies the above-mentioned TCP link status information for all the used TCP links.

  The flow control monitor 11 processes the information obtained from the RF link monitor 10 and the TCP link monitor 12, and outputs information necessary for determining the contents of the TCP flow control (S7). Information that the flow control monitor 11 notifies the TCP flow control unit 13 includes, for example, information indicating execution or stop of TCP flow control (TCP Flow Cont ON / OFF), and priority TCP identification information that specifies a TCP link for priority traffic. , RF link information, total traffic amount of each TCP link, RTT, packet loss amount, and measurement period.

  The TCP flow control unit 13 performs bandwidth reduction of the TCP link based on the information received from the flow control monitor 11 (S8).

FIG. 4 is a diagram for explaining the operation of the RF link monitor 10. As described above, the RF link monitor 10 transmits an RF link information request message to the wireless device 3 at a fixed period, and obtains RF link information as a response. The RF link information acquired at this time is sent to the flow control monitor 11 at a constant cycle after processing such as averaging from the previous acquisition. The RF link information includes, for example, received signal strength information (RSSI: Received Signal Strength Indication) and reception sensitivity information.

FIG. 5 is a diagram for explaining the operation of the flow control monitor 11. The flow control monitor 11 receives information from the RF link monitor 10 and the TCP link monitor 12 at regular intervals. The RF link monitor 10 receives the above-described RF link information. From the TCP link monitor 12, the total traffic amount of each TCP link, RTT, the amount of packet loss, and identification information indicating whether each TCP link is for priority traffic or non-priority traffic are received.

The flow control monitor 11 receives information for a predetermined number of times, calculates data necessary for determining the contents of the TCP flow control, and transmits the data to the TCP flow control unit 13. In the example of FIG. 5, the received information is accumulated 10 times and smoothed before notification. This is to alleviate the follow-up to sudden fluctuations in the wireless state.

  FIG. 6 is a flowchart showing the operation of the flow control monitor 11. The flow control monitor 11 receives the RF link information for the specified number of times (10 times), the total traffic amount, the RTT, and the packet loss amount for each TCP link (S21 to S23). Then, the RF link state is determined and the total traffic amount, RTT, and packet loss amount are calculated from the reception information for the specified number of times (S24).

The calculation method of the total traffic is made to correspond to the radio characteristics and the system characteristics by applying one of the following methods.
(1) The average of the number of receptions is calculated and defined as average value × number of receptions = total traffic.
(2) Record the maximum value of the received traffic for the specified number of times, and specify the maximum value × the number of received times = the total traffic amount.
(3) Record the minimum value of the received traffic for the specified number of times, and specify the minimum value × the number of received times = the total traffic amount.
The packet loss amount is calculated by detecting the missing TCP sequence number and calculating the number of lost packet bytes as the packet loss amount.

RTT monitors the response relationship between TCP data and ACK for each TCP link, and defines the average of the monitored response times as RTT. Among the response times, RTTs with an average RTT time + N hours or more are judged as delayed ACKs and are excluded from the measurement of the RTT average.

The determination of the RF link state is performed, for example, by receiving RF link information indicated in steps 1 to 5 for a specified number of times, and an average value is obtained as RF link state information.

  On the other hand, information (TCP Flow Cont ON / OFF) indicating the measurement cycle determined by the initial setting and the execution or stop of TCP flow control is obtained. The priority TCP identification information (IP Address / Port) indicating the TCP link for the priority traffic is obtained from the identification information indicating whether each TCP link received from the TCP link monitor 12 is for the priority traffic or the non-priority traffic. (S25)

The flow control monitor 11 calculates the total traffic amount, packet loss amount, RTT, measurement cycle, execution or stop of TCP flow control (TCP Flow Cont ON / OFF), priority TCP identification information ( IP Address / Port) is sent to the TCP flow control unit 13 (S26).

Next, the operation of the TCP flow control unit 13 will be described. FIG. 7 is a diagram for explaining the internal operation of the TCP flow control unit 13.
The TCP flow control unit 13 includes a plurality of target tables 30 indicating the relationship between the priority traffic bandwidth occupancy rate and the non-priority traffic suppression rate. Here, the priority traffic bandwidth occupancy corresponds to the ratio of priority traffic to the total traffic for a predetermined time. The non-priority traffic suppression rate is a value indicating how much the data amount of non-priority traffic should be suppressed. Each target table 30 is set with a different non-priority traffic suppression rate for the priority traffic bandwidth occupancy rate.

  First, the TCP flow control unit 13 periodically receives information from the flow control monitor 11 (S31), and checks whether the TCP Flow Cont is ON (S32). If it is ON, it is determined that it is necessary to execute TCP flow control, and the following processing is performed.

  Next, an appropriate target table 30 is selected from the plurality of target tables 30 based on the RF link state information, the packet loss amount, and the RTT (S33). For example, when the RF link state is poor and the amount of packet loss is large, the target table 30 in which the non-priority traffic suppression rate is set to a high value is selected.

  Based on the received information, the flow control monitor 11 calculates what percentage of the priority traffic bandwidth corresponds to the throughput within the specified time (corresponding to the above-mentioned priority traffic bandwidth occupancy) (S34).

Specifically, the calculation is performed according to the following procedures (1) to (4).
(1) The TCP link transmitting the priority traffic is specified by the priority TCP identification information.
(2) The traffic amount of the identified TCP link is calculated (when there are a plurality of TCP links for priority traffic, the total traffic amount is calculated for the plurality of TCP links). This value corresponds to the priority traffic band.
(3) The amount of traffic received by all the used TCP links is calculated as the total amount of received traffic.
(4) From the values of (2) and (3), the calculation formula: priority traffic bandwidth occupancy = priority traffic bandwidth / t ÷ total received traffic / t
To calculate the priority traffic bandwidth occupancy rate. (Where t represents a predetermined period)

One of steps S35 to S38 is selected according to the priority traffic band occupation ratio calculated in S34. For example, when the priority traffic bandwidth occupancy is X% or more and less than Y%, TCP ACK control and receivable window size control are performed so that the suppression rate of non-priority traffic becomes A% (S35).

  On the other hand, if the priority traffic bandwidth occupancy is less than X%, it is determined that suppression of non-priority traffic is unnecessary, and TCP ACK control and receivable window size control are stopped (S38).

The target of flow control is TCP traffic not corresponding to the priority TCP identification information, that is, non-priority traffic. For each TCP link that handles non-priority traffic, control for delaying the transmission timing of TCP ACK and control for reducing the receivable window size are performed. By this control, non-priority traffic can be suppressed.

By the procedure described above, traffic control of data (downlink) received from the base station, in particular, TCP flow of non-priority traffic can be dynamically suppressed. This control can be performed on a TCP link basis.
Further, by selecting an appropriate table from a plurality of target tables 30 according to the wireless characteristics of the wireless device 3, the packet loss state, and the RTT value, control linked to the wireless state and the state of the entire communication link is performed. Can be realized.

By suppressing the TCP flow for non-priority traffic, a free area is secured in the communication link, and the TCP flow for priority traffic is not suppressed, so that the TCP flow for priority traffic uses bandwidth preferentially. Yes.

In this embodiment, the contents of traffic control are switched using three threshold values of X, Y, and Z%, but the threshold values may be set more finely.
In the above example, the non-priority traffic suppression rate is set to 0%, A%, B%, or C%, but the priority traffic bandwidth occupancy shown in the target table 30 is The non-priority traffic suppression rate corresponding to the priority traffic bandwidth occupancy calculated in S34 is obtained from the relationship with the non-priority traffic suppression rate (curve of the target table 30, etc.), and control is performed so as to satisfy this suppression rate. good. In this case, finer control is possible.

  Furthermore, instead of the target table 30, the non-priority traffic suppression rate may be calculated from the priority traffic bandwidth occupancy rate using a calculation formula. In this case, the calculation formula to be used is changed according to the RF link state information and the packet loss amount.

In the above-described embodiment, both TCP ACK control and receivable window size control are performed in S35 to S37, but either may be performed. When the requested non-priority traffic suppression rate is low, either TCP ACK control or receivable window size control is executed. When the non-priority traffic suppression rate is high, TCP ACK control or receivable window is executed. The combination of control methods may be changed according to the suppression rate, such as executing both size control.
Thereby, even when the communication band is not sufficiently secured, the communication band of the non-priority traffic can be increased if the priority traffic does not flow temporarily.

  In the above-described embodiment, the method for suppressing non-priority traffic has been described. However, if there is a margin in the state of the TCP link, such as when priority traffic is not flowing or its amount is small, non-priority traffic is increased. Control may be performed. In this case, control for advancing the TCP ACK transmission timing and control for increasing the receivable window size are performed for each TCP link that handles non-priority traffic.

Embodiment 2. FIG.
In the first embodiment, the RF link information is notified from the RF link monitor 10 to the flow control monitor 11, but this processing can be eliminated. If the function of the RF link monitor 10 is omitted, information to be notified to the TCP flow control unit 13 is reduced, but the operation can be performed with a slight decrease in the control accuracy level.

  The present invention is applied to a communication device that is provided in a mobile device that performs wireless communication with a base station and performs TCP communication with an IP communication device (CN) on a network via the base station.

1 Mobile router 2 IP communication device (MN: mobile node)
3 Radio equipment (RF Module)
7 IP communication equipment (CN: Corespond node)
10 RF Link Monitor (RF Link Monitor)
11 Flow Control Monitor (Flow Control Monitor)
12 TCP Link Monitor (TCP Link Monitor)
13 TCP flow controller (TCP Flow Controller)

Claims (10)

In a mobile wireless communication device that performs wireless communication with a base station and performs TCP communication with an IP communication device on a network via the base station,
A TCP link monitoring unit for monitoring a flow of a plurality of TCP links used for the TCP communication and measuring a traffic amount for each TCP link;
Each TCP link in the plurality of TCP links is identified as either a TCP link for priority traffic or a TCP link for non-priority traffic, and the TCP link for non-priority traffic according to the traffic volume of the TCP link for priority traffic A TCP flow control unit for controlling the traffic volume of
A mobile radio communication apparatus comprising: The TCP flow control unit
The total traffic volume of the plurality of TCP links per predetermined time is calculated, the ratio of the traffic volume of the TCP link for priority traffic to the total traffic volume is calculated, and when the ratio exceeds a predetermined threshold, the non- 2. The mobile radio communication apparatus according to claim 1, wherein the traffic volume of the TCP link for priority traffic is suppressed.   The TCP flow control unit compares the ratio of the traffic amount of the priority traffic TCP link to the total traffic amount and a plurality of predetermined thresholds, and determines the TCP link for the non-priority traffic according to the comparison result. The mobile radio communication apparatus according to claim 2, wherein a traffic suppression rate is determined. When the ratio of the traffic amount of the priority traffic TCP link to the total traffic amount is smaller than the predetermined threshold, the TCP flow control unit stops the traffic suppression processing of the non-priority traffic TCP link The mobile radio communication apparatus according to claim 2. A target table defining a relationship between a ratio of the traffic amount of the TCP link for priority traffic to the total traffic amount and a suppression rate of required non-priority traffic;
The TCP flow control unit obtains a suppression rate of the non-priority traffic corresponding to the calculated ratio using the target table, and suppresses the traffic amount of the TCP link for the non-priority traffic so as to satisfy the suppression rate. The mobile radio communication apparatus according to claim 2, wherein: The TCP flow control unit has a plurality of target tables each having a different suppression rate of the requested non-priority traffic, selects one target table from the plurality of target tables, and selects the selected target table. 6. The mobile radio communication apparatus according to claim 5, wherein a traffic amount of the TCP link for non-priority traffic is suppressed based on the basis. A wireless link monitoring unit that monitors a state of wireless communication with the base station and outputs wireless link information indicating the state of the wireless communication;
7. The mobile radio communication apparatus according to claim 6, wherein the TCP flow control unit selects one target table from the plurality of target tables based on the radio link information. The TCP flow control unit
For the non-priority traffic TCP link, adjust the timing for transmitting an ACK signal to the IP communication device on the network, or for the non-priority traffic TCP link, adjust the receivable window size to adjust the non-priority traffic. 2. The mobile radio communication apparatus according to claim 1, wherein a traffic amount of downlink data received from the base station is controlled by a traffic TCP link. In a TCP flow control device provided in a mobile wireless communication device that performs wireless communication with a base station and performs TCP communication with an IP communication device on a network via the base station,
TCP that monitors the flow of a plurality of TCP links used for TCP communication between the IP communication device on the network and the IP communication device provided in the mobile radio communication device, and measures the traffic amount for each TCP link A link monitoring unit;
Each TCP link in the plurality of TCP links is identified as either a TCP link for priority traffic or a TCP link for non-priority traffic, and the TCP link for non-priority traffic according to the traffic volume of the TCP link for priority traffic TCP flow control device having a TCP flow control unit for controlling the traffic volume of the network. A TCP flow control method executed in a mobile radio communication apparatus that performs radio communication with a base station and performs TCP communication with an IP communication apparatus on a network via the base station,
A measurement step of monitoring a flow of a plurality of TCP links used for the TCP communication and measuring a traffic amount for each TCP link;
Identify each TCP link in the plurality of TCP links as either a priority traffic TCP link or a non-priority traffic TCP link, and depending on the traffic volume of the priority traffic TCP link measured in the measurement step A TCP flow control step for suppressing the traffic amount of the TCP link for non-priority traffic;
A TCP flow control method characterized by comprising:

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