JP2011250223A - Gateway device and packet buffer management method in gateway device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gateway device which is interconnected with a wireless network and a core network with enhanced throughput by optimizing packet transfer per connection.SOLUTION: A packet buffer management part is provided in a packet processor of a gateway device to consolidate packet transfer per connection. Throughput of the packet transfer is enhanced by increasing/decreasing a maximum window size and an advertisement window size dynamically per connection according to a traffic state per connection and the remaining amount of a packet buffer.

Description

  The present invention relates to a gateway device. In particular, the present invention relates to a packet buffer management method for a packet processing device in an application gateway device.

  In recent years, transmission and reception of content such as moving images and audio from mobile terminals via a network has been actively performed. FIG. 2 shows a configuration example of a communication system in which a user receives various services from a content server using a mobile terminal. Here, an application gateway device is inserted between the portable terminal and the content server, and relays transmission / reception of packet data. An application gateway device is a relay device intended to ensure security by using a proxy program that relays communication. For example, when connecting to the Internet from an in-house terminal, the in-house terminal is not directly connected to the outside, and the Web service can be used safely and securely by relaying the application gateway device. Also in connection between a portable terminal and a content server, it is important to ensure security because of the necessity of content billing processing and the like, and communication that ensures security is performed by relaying an application gateway device.

  As shown in FIG. 2, the mobile terminal 4 is connected to the application gateway device 13 via the wireless network 3. On the other hand, the application gateway device 13 is connected by wire on the core network 14 side, and the content server 2 is connected to the core network 14. Such a configuration is called a mobile core network. The data to be transmitted / received includes a flow of downlink packet data transmitted from the content server 2 to the mobile terminal 4 and a flow of uplink packet data transmitted from the mobile terminal to the content server. In particular, a high throughput of packet data in the downstream direction is required. For example, the stream data of the content server 2 flows as downlink packet data, relays through the application gateway device 13, is transmitted to the mobile terminal 4 via the wireless network 3, and the mobile terminal 4 reproduces video and audio. Is done.

  In the packet processing device 1 of the application gateway device 13, processing is performed after the packet data is accumulated in the packet buffer. However, since the size of the packet buffer is limited, a large amount of downstream packets are sent from the content server 2. The packet of the packet processing device 1 overflows. Therefore, the reception side informs the transmission side of the amount of receivable packets as a window size, and the transmission side sends only a receivable amount of packets so that a buffer overflow does not occur. Such a method is generally called flow control.

  In addition, since the application gateway device 13 communicates with a plurality of portable terminals 4, many TCP connections are generated. Conventionally, a fixed maximum window from connection establishment to disconnection is established for all TCP connections. The size was set, and window control was performed while maintaining a constant size during connection. FIG. 7 shows the maximum window size for each connection of the packet buffer. Here, the maximum window size is a buffer size that can be used at the maximum in the connection.

  By the way, when a plurality of users use mobile terminals to relay application gateway devices and transmit / receive to / from the content server, usage conditions vary depending on the users. For example, when a user browses a moving image on a mobile terminal, the amount of packets in the connection is very large, and the moving image may be interrupted if the buffer size is small. On the other hand, when other users receive only text data with a small amount of data, the packet amount of the connection is small and the buffer size is small.

  However, in the conventional application gateway apparatus, as shown in FIG. 7, since a common buffer size is allocated for each connection, there is a limit when trying to increase the throughput of the packet processing apparatus.

  On the other hand, as one of congestion control methods in TCP, there is a method called TCP Vegas. This is to prevent congestion by using the increase in round trip time for congestion detection and changing the congestion window size according to the traffic situation of the network. Patent Document 1 discloses a method of changing the congestion window size so that the TCP Vegas method can be improved to follow a rapid change in traffic. According to this method, by changing the congestion window size according to the traffic situation, there is no congestion and effective transmission / reception becomes possible.

JP 2005-218069 A

  The following analysis is given by the present invention.

  However, in the method of Patent Document 1, although the congestion window size is changed according to the traffic situation to prevent congestion and enable effective transmission / reception, the maximum window size is not controlled for each connection. For this reason, an optimal packet buffer cannot be assigned to each connection for a plurality of connections, and there is a limit to improving the throughput of the packet processing device.

  Here, the problem with the conventional application gateway device is that the maximum window size is not controlled on a connection basis, so the packet transfer throughput cannot be sufficiently improved for a connection with a large amount of traffic. This means that the packet transfer processing capacity cannot be increased.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a gateway device having a packet processing device with improved packet transfer processing capability.

  A gateway device according to a first aspect of the present invention is a gateway device for interconnecting a wireless network to which a terminal device is connected and a core network to which a server device is connected, the gateway device receiving packet data A packet processing device for transmitting and receiving, wherein the packet processing device includes a packet buffer for storing the packet data, and a packet buffer management unit for centrally managing the packet buffer. The maximum window size and the advertisement window size for each connection are increased or decreased based on the state and the remaining amount of the packet buffer.

  A communication system according to a second aspect of the present invention includes a terminal device, a wireless network connected to the terminal device, a gateway device transmitting and receiving to and from the wireless network, a core network connected to the gateway device, and the core The gateway device includes a packet processing device that transmits and receives packet data, the packet processing device including a packet buffer that stores the packet data, and traffic in connection units. And a packet buffer management unit configured to increase or decrease the maximum window size and the advertisement window size for each connection based on the status and the remaining amount of the packet buffer.

  According to a third aspect of the present invention, there is provided a packet buffer management method in a packet processing apparatus, comprising: obtaining a traffic volume for each connection; and determining a maximum for each connection based on a remaining amount of the packet buffer and the traffic volume for each connection. And increasing / decreasing the window size and the advertisement window size.

According to the present invention, the following effects can be obtained.
The first effect is that it is possible to provide a gateway device with improved packet transfer processing capability. The reason is that the packet buffer management unit in the gateway device dynamically controls the maximum window size for each connection based on the traffic state of each connection and the remaining amount of packet buffer. This is because the packet transfer throughput can be increased, and the packet transfer processing capability per packet processing apparatus can be increased.

  The second effect is that communication in which a packet data transfer processing capability is enhanced in a communication system including a wireless network connected to a terminal device, a server connected to a core network, and a gateway device that relays both. The system can be provided. The reason is that the packet buffer management unit in the gateway device dynamically controls the maximum window size for each connection based on the traffic state of each connection and the remaining amount of packet buffer. This is because the packet transfer throughput can be increased, and the packet transfer processing capability per packet processing apparatus can be increased.

  A third effect is that it is possible to provide a packet buffer management method in a packet processing device with improved packet transfer processing capability. The reason for this is that in the packet processing device, the maximum window size for each connection is dynamically controlled based on the traffic status of each connection and the remaining capacity of the packet buffer. This is because the packet transfer processing capability can be increased by managing the packet buffer so that

It is a block diagram which shows the structure of the packet processing apparatus of the 1st Embodiment of this invention. It is a block diagram which shows the structure apparatus of the mobile core network of this invention. It is a flowchart which shows operation | movement of the packet buffer management method of the 2nd Embodiment of this invention. It is a figure showing the packet buffer for demonstrating Example 1 of this invention. It is a figure showing the connection management table for demonstrating Example 1 of this invention. It is a figure showing the traffic table for demonstrating Example 1 of this invention. It is a figure showing the conventional packet buffer. It is a flowchart which shows operation | movement of Example 1 of this invention. It is a figure for demonstrating Example 1 of this invention. It is a figure for demonstrating Example 1 of this invention. It is a figure for demonstrating Example 1 of this invention. It is a figure for demonstrating Example 1 of this invention.

  Embodiments of the present invention will be described with reference to the drawings as necessary. In addition, drawing quoted in description of embodiment and the code | symbol of drawing are shown as an example of embodiment, and, thereby, the variation of embodiment by this invention is not restrict | limited.

  As shown in FIGS. 1 and 2, the gateway device according to the first aspect of the present invention is a gateway device for interconnecting a wireless network 3 to which a terminal device is connected and a core network 14 to which a server device is connected. The gateway device includes a packet processing device 1 that transmits and receives packet data. The packet processing device 1 includes a packet buffer 6 that accumulates packet data and a packet buffer management unit 9 that centrally manages the packet buffer 6. In addition, the packet buffer management unit 9 is characterized by increasing or decreasing the maximum window size and the advertisement window size for each connection based on the traffic state for each connection and the remaining amount 10 of the packet buffer.

  As shown in FIGS. 1 and 2, a communication system according to a second aspect of the present invention includes a terminal device, a wireless network 3 connected to the terminal device, a gateway device that transmits and receives to and from the wireless network 3, and a gateway device. The gateway device includes a core network 14 to be connected and a server device connected to the core network 14, and the gateway device includes a packet processing device 1 that transmits and receives packet data. The packet processing device 1 stores packet data. And a packet buffer management unit 9 that increases / decreases the maximum window size and the advertisement window size for each connection based on the traffic state of each connection and the remaining amount 10 of the packet buffer.

  As shown in FIG. 3, the packet buffer management method in the packet processing apparatus 1 according to the third aspect of the present invention includes step S1 for obtaining the traffic volume in connection units, the remaining amount 10 of the packet buffer, and the traffic volume in connection units. And step S2 for increasing / decreasing the maximum window size and the advertisement window size in connection units.

  Hereinafter, embodiments will be described in detail with reference to the drawings.

[Configuration of Example 1]
FIG. 2 is a block diagram of the communication system according to the first embodiment of the present invention. In FIG. 2, an application gateway device 13 which is a component device of the mobile core network is shown. In FIG. 2, the application gateway device 13 includes a packet processing device 1 and a call processing device 5. The packet processing device 1 performs user plane processing. The call processing device 5 performs control plane processing. The application gateway device 13 includes a wired interface and is connected to a counter device (for example, the content server 2). The application gateway device 13 controls connection with the wireless network 3 and is connected to the opposite device (for example, the mobile terminal 4). The application gateway device 13 transfers packet data between the content server 2 and the mobile terminal 4. A downstream TCP packet transmitted from the content server 2 is received and transferred to the mobile terminal 4, and an upstream TCP packet transmitted from the mobile terminal 4 is received and transferred to the content server 2.

  Referring to FIG. 1, the detailed configuration of the packet processing device 1 in the application gateway device 13 shown in FIG. 2 is shown. In FIG. 1, a packet transfer unit 7 sequentially transfers a downstream TCP packet from the content server 2. The packet buffer management unit 9 centrally manages the remaining amount 10 of the packet buffer in the packet processing apparatus 1 and the maximum window size and advertisement window size of all connected TCP connections by the connection management table 11. The packet buffer management unit 9 monitors traffic in the packet processing device 1, collects statistical data of transmission / reception packet data for all TCP connections that pass through, as traffic information, and centrally manages the traffic table 12. The application layer processing unit 8 communicates with the packet transfer unit 7 to perform application layer protocol processing of packet data.

  Although the configuration of the embodiment has been described in detail above, the call processing device 5 in FIG. 2 is widely known and is not directly related to the present invention, and thus the detailed configuration is omitted.

[Operation of Embodiment 1]
First, before describing the operation of the packet processing apparatus of FIG. 1, flow control in transmission / reception of TCP packets will be described below. The basis of TCP is to repeat “transmit one TCP packet and receive one ACK packet” as shown in FIG. This method has high communication reliability, but the transmission side has to wait for the ACK to return every time one TCP packet is sent, resulting in poor communication efficiency. Therefore, in TCP, in order to increase communication efficiency, as shown in FIG. 10, a method is used in which the transmission side continuously sends a certain number of TCP packets, and the reception side collectively returns ACK. However, on the receiving side, if there is no free space in the packet buffer, TCP packets sent together cannot be received, and a buffer overflow occurs.

  Therefore, the transmission side informs the transmission of the data size that can be continuously received at one time, so that the transmission side limits the amount of packets sent at a time to the amount notified by the reception side. The data size that can be continuously received by the receiving side at a time is called the advertisement window size. In TCP, as shown in FIG. 11, a connection is established by a three-way handshake, but when the receiving side returns SYN + ACK to the transmitting side, the advertisement window size is written in the window size area of the TCP header and transmitted. By sending it to the sender, the sender is informed of the advertisement window size.

  Based on the basic flow control of TCP described above, the operation at the time of establishing a TCP connection in the packet processing apparatus 1 of the first embodiment will be described. In the downstream packet data flow, the application gateway device 13 receives the packet data from the content server 2. On the receiving side, the received packet data is stored in the packet buffer 6. When there is one connection connection, the advertisement window size on the reception side may be the remaining amount of packet buffer 10. When the TCP connection is established, when the reception side returns SYN + ACK to the transmission side, the advertisement window size is set in the window size area of the TCP header. The remaining amount 10 of the packet buffer may be written and notified to the transmission side. Further, when the remaining amount 10 of the packet buffer decreases during the connection, the advertisement window size may be reduced and the updated advertisement window size may be notified to the transmission side.

図４に、ｎ個のコネクション接続がある場合のパケットバッファ６の状態を示す。ここで、ｎ個のコネクションの広告ウィンドウサイズの合計が、パケットバッファの残量１０より小さくなるように、パケットバッファ管理部９が一元管理する。 On the other hand, when n TCP connection connections are made, the sum of the advertisement window sizes of all the connections is set to be 10 or less of the remaining amount of the packet buffer as shown in Expression (1).

FIG. 4 shows the state of the packet buffer 6 when there are n connection connections. Here, the packet buffer management unit 9 performs unified management so that the total of the advertisement window sizes of the n connections is smaller than the remaining amount 10 of the packet buffer.

  If the remaining amount 10 of the packet buffer becomes small and becomes smaller than the total of the advertisement window sizes of all the connections, the packet buffer management unit 9 takes measures to reduce the advertisement window size for each connection, Avoid overflow.

  Also, if the packet buffer remaining capacity 10 becomes 0, the packet buffer management unit 9 sets the advertisement window size of all connections to 0, informs the transmission side, and waits for the packet buffer transmission. And the generation of a new TCP connection is prohibited. Then, after the elapse of a certain time, when the remaining amount 10 of the packet buffer increases, the advertisement window is increased accordingly, and transmission of packet data or generation of a new connection is resumed.

  At the time of establishing a connection, each connection sets a maximum window size that is an upper limit value of a usable packet buffer. When it is determined that the amount of data from the transmission side is large at the time of establishing a connection, the packet buffer management unit 9 sets the maximum window size to a large value, whereas when it is determined that the amount of data is small Set to a small value. For example, in the case of a connection including moving image browsing, the maximum window size is set to a large value, and in the case of a connection that only receives text data with a small amount of data, the maximum window size is set to a small value.

The packet buffer management unit 9 must satisfy the relationship of the following formula (2) with respect to the relationship between the maximum window size for each connection and the advertisement window size.

Advertising window size ≤ maximum window size Formula (2)

In this way, the maximum window size and advertisement window size at the time of establishing a connection determined by the packet buffer management unit 9 are stored in the connection management table 11 of the packet buffer management unit 9. Further, the connection management table 11 is updated every time the maximum window size or the advertisement window size is changed after the connection is established. Further, the remaining amount 10 of the packet buffer is simultaneously stored in the connection management table 11.

  In addition, when the maximum window size is set for a certain connection, the memory management for each connection does not allocate a maximum window size area on the memory map of the packet buffer 9 but assigns the memory size to be used to the packet buffer. Manage as part of the size. As a result, the maximum window size can be dynamically increased or decreased during connection.

  Next, operations will be described in the case where downstream data flows from the content server 2 to the application gateway device 13 after the connection is established.

  The packet buffer 6 accumulates packet data of all TCP connections passing through the packet processing device 1 in a single buffer pool. The remaining amount 10 of the packet buffer is calculated by increasing / decreasing by receiving packet data from the packet transfer unit 7 or transmitting packet data to the application layer processing unit 8. The calculated remaining amount 10 of the packet buffer is set in the connection management table 11 of the packet buffer management unit 9. When the packet processing device 1 receives a downstream TCP packet from the content server 2, the packet transfer unit 7 receives the packet data within the advertisement window size and writes the packet data in the packet buffer 6. Since the written packet data uses the packet buffer 6, the remaining amount 10 of the packet buffer is subtracted. The written packet data is transmitted to the application layer processing unit 8 via the socket. When packet data is transmitted from the packet buffer 6 to the application layer processing unit 8, the remaining amount 10 of the packet buffer increases. For example, the application layer processing unit 8 performs addition / deletion of a number (terminal ID) for identifying a subscriber, addition / deletion of an amount corresponding to the content, etc. for content billing processing required by the carrier. Yes. After the processing in the application layer processing unit 8 is finished, the processed data is received and converted into packet data, which is stored in the packet buffer 6. At this stage, the remaining amount of packet buffer decreases. Next, this packet buffer is transmitted to the portable terminal 4 via the wireless network 3 by a connection established between the application gateway device 13 and the portable terminal 4.

  The packet buffer management unit 9 centrally manages the use of packet buffers for all TCP connections by using the connection management table 11. The packet buffer management unit 9 communicates with the packet transfer unit 7 through a bidirectional control interface, and sets the maximum window size and advertisement window size for all TCP connections to be connected in the connection management table 11. FIG. 5 shows an example of the connection management table 11 managed by the packet buffer management unit 9.

  Based on the traffic information of the packet processing device 1, the packet buffer management unit 9 creates a traffic table 12 for managing the load status of the packet processing device 1 and centrally manages it. The created traffic table 12 is registered in the memory of the packet processing device 1. The packet buffer management unit 9 communicates with the packet transfer unit 7 through a bi-directional control interface. Through the control interface, the packet length, the number of packets, and the amount of communication data of all transmitted and received TCP connections are statistical data. The packet is sent to the packet buffer management unit 9 periodically (for example, every second). FIG. 6 shows an example of the traffic table 12 managed by the packet buffer management unit 9. The packet buffer management unit 9 monitors traffic in the packet processing device 1, collects statistical data, and creates a traffic table 12.

  Next, increase / decrease in the maximum window size and the advertisement window size after the connection is established will be described with reference to the flowchart of FIG. First, when the packet processing device 1 receives packet data, the packet transfer unit accesses the packet buffer management unit 9 via the control interface, reads the traffic table 12 in step S11 of FIG. 8, and calculates the total traffic volume. Do. Next, in step 12, the total traffic amount is compared with a predetermined value T1. If it is determined that the total amount of traffic in the packet processing device 1 is less than the predetermined value T1 based on the statistical data of the referenced traffic table 12, in step S13, for a connection with a lot of traffic based on the traffic table 12, Preferentially increase the configured maximum window size. Here, the traffic is calculated with the current usage ratio relative to 100% when the transmission band between the content server and the application gateway is fully used. For example, when the traffic is 30% or less, it is determined that the traffic is low.

  In addition, the calculation method of the increase amount of the maximum window size in step S13 determines, for example, the total increase amount that increases as a whole in a range in which the sum of the maximum window sizes of all connections does not exceed the packet buffer size. By obtaining an increment ratio corresponding to the traffic defined by the table shown in FIG. 12, and allocating the total increase amount of the maximum window size to each connection based on the increment ratio, the maximum window size of each connection is obtained. Gain an increase. By doing so, the maximum window size can be preferentially increased for connections with a lot of traffic, so that the packet transfer processing capability of the packet processing device 1 can be improved efficiently. Then, the current maximum window size is increased by an increase amount, set as a new maximum window size, and the maximum window size in the connection management table 11 is updated.

  On the other hand, if the total traffic volume is not smaller than the predetermined value T1 in the comparison in step S12, the maximum window size in each connection is returned to the maximum window size set at the time of connection establishment in step S14, and the connection management table 11 The maximum window size at is updated and the above operation is repeated. Here, as shown in FIG. 5, the maximum window size at the time of establishing a connection is stored in the connection management table 11 separately from the maximum window size to be updated, and is read from there and referred to.

  Next, in steps S15 and S16, the connection management table 11 is referred to, and the total advertisement window size set in all the TCP connections connected at the time of receiving the packet data segment and the remaining amount 10 of the packet buffer. Compare with Specifically, as shown in step S15, a value eval is calculated by subtracting the sum of the advertising windows from the remaining amount 10 of the packet buffer. If eval is between 0 and ε, the sum of the advertising window sizes is calculated. Is determined to be appropriate. ε is a positive number and is an allowable value for bringing the total advertisement window size close to the remaining amount of the packet buffer. If eval is greater than ε, it is determined to increase the total advertisement window size, and the advertisement window size is increased in step S17. Here, the increase in the advertisement window size for each connection may increase the advertisement window size preferentially for a connection with a lot of traffic using the increment ratio with respect to the traffic amount in FIG. desirable. If eval is smaller than 0, the condition of equation (1) is not satisfied, and buffer overflow may occur. Therefore, in step S18, the advertisement window size for each connection is reduced. After steps S16, S17, and S18, after a predetermined time by a timer process in step S19, the process returns to step S11 and the process is repeated.

  Here, when the maximum window size or the advertisement window size is changed in steps S13, S14, S17, and S18, the connection management table is updated. At the same time, the remaining amount 10 of the packet buffer is also stored in the connection management table.

  As described above, the above operations in steps S11 to S19 are repeated, the remaining amount 10 of the packet buffer, the connection management table 11 and the traffic table 12 are centrally managed, the traffic in the packet processing device 1 is monitored, and the maximum for each TCP connection The window size is dynamically controlled, and the advertisement window size is adjusted to an optimum amount based on the relationship with the remaining amount of the packet buffer.

  In the flowchart of FIG. 8, only when the total traffic volume is smaller than the predetermined value T1, the maximum window size is increased or the advertisement window size is increased or decreased. For example, steps S12 and S14 are deleted, Step S13 may be executed. Further, step S13 may be increased or decreased based not only on the increase process but also on the traffic volume in units of content. In addition, various variations of configurations that increase or decrease the maximum window size and the advertisement window size according to the traffic amount are possible.

  As described above, according to the present invention, for example, the maximum window size set for each TCP connection at the time of establishing a connection for a connection that requires a large amount of packet data communication temporarily during a time period when traffic is low. Can be preferentially expanded, the throughput of packet transfer per packet processing device can be increased according to the variation of the traffic model passing through the packet processing device, and the packet processing capacity of the packet processing device can be maximized be able to.

  Further, according to the amount of packet data to be communicated, the packet transfer throughput of the user's connection can be increased, and the communication that secures the optimum throughput can be provided to the user who uses the mobile terminal.

  In addition, the amount of memory allocated to the packet buffer as a packet processing device can be reduced, and the packet processing device can be reduced in size.

  The present invention can be widely applied to network transmission that optimizes packet transfer for a plurality of TCP connections. Specifically, it is useful for data communication in a plurality of mobile terminals connected to a network.

  It should be noted that the embodiments and examples can be changed and adjusted within the scope of the entire disclosure (including claims) of the present invention and based on the basic technical concept. Various combinations and selections of various disclosed elements are possible within the scope of the claims of the present invention. That is, the present invention of course includes various variations and modifications that could be made by those skilled in the art according to the entire disclosure including the claims and the technical idea.

DESCRIPTION OF SYMBOLS 1 Packet processing device 2 Content server 3 Wireless network 4 Portable terminal 5 Call processing device 6 Packet buffer 7 Packet transfer unit 8 Application layer processing unit 9 Packet buffer management unit 10 Remaining amount of packet buffer 11 Connection management table 12 Traffic table 13 Application gateway Device 14 core network

Claims (10)

A gateway device for interconnecting a wireless network to which a terminal device is connected and a core network to which a server device is connected,
The gateway device has a packet processing device for transmitting and receiving packet data,
The packet processing device includes a packet buffer that accumulates the packet data, and a packet buffer management unit that centrally manages the packet buffer,
The gateway apparatus according to claim 1, wherein the packet buffer management unit increases or decreases the maximum window size and the advertisement window size for each connection based on a traffic state for each connection and a remaining amount of the packet buffer. When the total traffic volume that is the sum of the traffic volume in connection units is smaller than a predetermined value, the packet buffer management unit increases the maximum window size in connection units,
Further, when the remaining amount of the packet buffer is larger than the sum of the advertisement window sizes, the packet buffer management unit increases the advertisement window size for each connection,
The gateway device according to claim 1, wherein when the remaining amount of the packet buffer is smaller than the total of the advertisement window sizes, the packet buffer management unit decreases the advertisement window size.   3. The gateway according to claim 1, wherein when the maximum window size for each connection or the advertisement window size is increased, the gateway is preferentially increased for a connection with a large traffic volume for each connection. 4. apparatus. In the packet buffer management unit, the maximum window and the advertisement window are managed by a connection management table,
The gateway device according to any one of claims 1 to 3, wherein the traffic volume is managed by a traffic table. A terminal device;
A wireless network connected to the terminal device;
A gateway device for transmitting and receiving to and from the wireless network;
A core network connected to the gateway device;
A server device connected to the core network,
The gateway device has a packet processing device for transmitting and receiving packet data,
The packet processing device includes a packet buffer for storing the packet data;
A communication system, comprising: a packet buffer management unit that increases or decreases the maximum window size and the advertisement window size for each connection based on a traffic state for each connection and a remaining amount of the packet buffer. When the total traffic volume, which is the total traffic volume of the connection unit, is smaller than a predetermined value,
The packet buffer management unit increases the maximum window size for each connection,
Further, when the remaining amount of the packet buffer is larger than the total of the advertisement window sizes, the packet buffer management unit increases the connection-unit advertisement window size,
6. The communication system according to claim 5, wherein when the remaining amount of the packet buffer is smaller than the total of the advertisement window sizes, the packet buffer management unit decreases the advertisement window size.   The communication according to claim 5 or 6, wherein when the maximum window size for each connection or the advertisement window size is increased, the connection is preferentially increased for a connection with a large traffic volume for each connection. system. Obtaining the traffic volume per connection;
A packet buffer management method in a packet processing apparatus, comprising: increasing or decreasing a maximum window size and an advertisement window size for each connection based on a remaining amount of the packet buffer and a traffic volume for each connection. A first comparison step of comparing the total traffic volume that is the sum of the traffic volume in connection units with a predetermined value;
Increasing the maximum window size when the total traffic volume is smaller than a predetermined value in the first comparison step;
A second comparison step of comparing the remaining amount of the packet buffer with the sum of the advertising window sizes in connection units;
In the second comparison step, when the remaining amount of the packet buffer is larger than the total of the advertisement window sizes for each connection, increasing the advertisement window size;
9. The method according to claim 8, further comprising: reducing the advertisement window size when the packet buffer remaining amount is smaller than a total of the advertisement window sizes for each connection in the second comparison step. Packet management method in the packet processing apparatus.   10. The packet according to claim 8, wherein when the maximum window size for each connection or the advertisement window size is increased, the packet is preferentially increased for a connection with a large amount of traffic for each connection. 11. A packet buffer management method in a processing apparatus.

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