WO2018047645A1 - Communication device and communication method - Google Patents

Abstract

Provided is a communication device, which communicates with another communication device in accordance with MPTCP. The communication device comprises: an application control unit which controls an application; a communication control unit which controls at least two MPTCP subflows; at least two communication units which communicate data via the subflows using IP addresses; and an information retaining unit which retains information of the subflows which includes the IP addresses which are used with the subflows. If the subflow has been changed, the information retaining unit retains information of the changed subflow. The application control unit references the information of the changed subflow.

Description

Communication apparatus and communication method

The present disclosure relates to a communication device and a communication method.

MPTCP (Multipass TCP) is known as TCP (Transmission Control Protocol) that handles multiple paths. As smartphones that communicate according to MPTCP, those in which a TCP connection in wide-area wireless communication, a TCP connection in wired communication, and a TCP connection in short-range wireless communication are managed by the MPTCP core as TCP subflows are known. Also, as disclosed in Patent Document 1, for example, this MPTCP core establishes a single MPTCP connection by combining three TCP subflows, and MPTCP connection information is transferred to an application program by a socket API (Application Program Interface). To provide.

For example, in the case where a part of TCP connection is disconnected due to movement of a smartphone, the present disclosure allows the application to recognize the information of the TCP subflow changed by MPTCP, and suppresses a communication error in execution of the application. With the goal.

JP 2014-127790 A

The communication device of the present disclosure communicates with other communication devices according to MPTCP. The communication apparatus uses an application control unit that controls an application, a communication control unit that controls at least two subflows of MPTCP, at least two communication units that communicate data via a subflow using an IP address, and a subflow. And an information holding unit for holding information on the subflow including the IP address to be stored. When the subflow is changed, the information holding unit holds information on the changed subflow. The application control unit refers to the changed subflow information.

The communication method of the present disclosure is a communication method that performs communication according to MPTCP, controls at least two subflows of MPTCP using an IP address, and holds information on the subflow including the IP address used for the subflow in an information holding unit. When data is communicated via the subflow and the subflow is changed, the information of the changed subflow is held in the information holding unit, and the application control unit that controls the application refers to the information of the changed subflow.

According to the present disclosure, for example, when a part of TCP connection is disconnected due to movement of a smartphone, the application can recognize the information of the TCP subflow changed by MPTCP, and suppress communication errors in the execution of the application. it can.

FIG. 1 is a schematic diagram illustrating a configuration example of a communication system according to the first embodiment. FIG. 2 is a block diagram illustrating a hardware configuration example of the communication apparatus. FIG. 3 is a block diagram illustrating a functional configuration example of the communication apparatus. FIG. 4 is a sequence diagram showing an operation when a communication system without an API executes FTP according to MPTCP. FIG. 5A is a flowchart illustrating an operation example when a communication system including an API executes FTP according to MPTCP. FIG. 5B is a flowchart illustrating an operation example when the communication system including the API executes FTP according to MPTCP. FIG. 5C is a flowchart illustrating an operation example when the communication system including the API executes FTP according to MPTCP. FIG. 6 is a sequence diagram showing an operation when a communication system without an API executes AMQP according to MPTCP. FIG. 7A is a flowchart illustrating an operation example when a communication system including an API executes AMQP according to MPTCP. FIG. 7B is a flowchart illustrating an operation example when the communication system including the API executes AMQP according to MPTCP. FIG. 7C is a flowchart illustrating an operation example when a communication system including an API executes AMQP according to MPTCP. FIG. 8 is a block diagram illustrating another functional configuration example of the communication apparatus.

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the claimed subject matter.

(First embodiment)
[Configuration]
FIG. 1 is a schematic diagram illustrating a configuration example of a communication system 10 according to the first embodiment. The communication system 10 includes a plurality of communication devices 100. The plurality of communication devices 100 are connected via the network NT. The communication device 100 includes, for example, a mobile terminal 100A and a server 100B. In this embodiment, as an example, it is assumed that the mobile terminal 100A and the server B communicate according to MPTCP via the network NT.

The mobile terminal 100A includes, for example, a PC (Personal Computer), a smartphone, a mobile phone, a camera, a robot, and a drone (unmanned aerial vehicle). The robot is, for example, a security robot. The mobile terminal 100A functions as a client terminal.

The server 100B may be a relay device or a base station device. The relay device includes, for example, an AP (Access Point) and a gateway device.

The network NT may include a wireless network or a wired network. The network NT may include a dedicated network or a public network. The network NT includes the Internet, an intranet, a cellular network, a WAN (Wide Area Network), a LAN (Local Area Network), and the like. The network NT may include a network related to near field communication or Bluetooth (registered trademark).

In the communication system 10, the mobile terminal 100A and the server 100B perform data communication according to MPTCP by a predetermined communication method via the network NT. The portable terminal 100A and the server 100B communicate audio data, image data, control data, and the like. The portable terminal 100A and the server 100B can communicate by a plurality of communication methods.

Communication methods include, for example, wired LAN communication, wireless LAN communication, USB (Universal Serial Bus) communication, DECT (Digital Enhanced Cordless Communication), LTE (Long Term Evolution), LTE-Advanced, Near-distance, Millimeter-wave communication, Includes wireless communication and Bluetooth (registered trademark) systems.

Next, the configuration of the communication device 100 will be described.

FIG. 2 is a block diagram illustrating a hardware configuration example of the communication apparatus 100. The communication device 100 includes a CPU (Central Processing Unit) 101, a memory 102, communication control I / Fs (Interface) 103 and 105, and communication I / Fs 104 and 106. The portable terminal 100A and the server 100B are examples of the communication device 100 and have the same configuration, and therefore will be described together here. Here, the number of communication control I / Fs and communication I / Fs is exemplified as two, but may be three or more.

The CPU 101 cooperates with the memory 102 to perform various processes and controls. Specifically, the CPU 101 implements each function of the communication apparatus 100 by executing a program held in the memory 102. This program includes, for example, an OS (Operating System), middleware, and an application.

The memory 102 stores, for example, various data, information, and programs. The memory 102 may be built in the CPU 101. The memory 102 may include a secondary storage device and a tertiary storage device together with the primary storage device. The primary storage device includes, for example, a RAM (Random Access Memory) and a ROM (Read Only Memory). Secondary storage devices include, for example, an HDD (Hard Disk Drive) and an SSD (Solid State Drive). The tertiary storage device includes, for example, a USB flash memory and an SD card.

The communication control I / Fs 103 and 105 control communication by the communication I / Fs 104 and 106. Communication I / Fs 104 and 106 communicate according to various communication methods. The communication methods of the communication I / F 104 and the communication I / F 106 are different, for example. For example, the communication I / F 104 follows, for example, a wireless LAN communication method, and the communication I / F 106 follows, for example, an LTE communication method.

Note that the hardware configuration of the mobile terminal 100A and the hardware configuration of the server 100B are the same. When the mobile terminal 100A and the server 100B are distinguished from each other in the same block in FIG. 2, the constituent blocks of the mobile terminal 100A are suffixed with “A” and the constituent blocks of the server 100B are included. Is described with “B” at the end of the reference numeral.

FIG. 3 is a block diagram illustrating a functional configuration example of the communication device 100 (the mobile terminal 100A and the server 100B).

The CPU 101 and the communication control I / F 103 implement each function of the communication device 100 by executing a program held in the memory 102. Each of these functions includes functions of an application control unit 151, an API 152, an MPTCP control unit 153, and TCP communication units 154 and 155, which will be described later. That is, the communication apparatus 100 includes an application control unit 151, an API 152, an MPTCP control unit 153, and TCP communication units 154 and 155.

In FIG. 3, the functional blocks of the mobile terminal 100A and the functional blocks of the server 100B are the same. When the mobile terminal 100A and the server 100B are distinguished from each other in the same functional block of FIG. 3, the functional block of the mobile terminal 100A is suffixed with “A” and the functional block of the server 100B. Will be described with “B” appended to the end of the reference numeral.

Application control unit 151 (151A, 151B) executes an application (application program) held in memory 102 in the seventh layer (application layer) of the OSI reference model. Then, the application control unit 151 performs control related to the application.

API 152 (152A, 152B) exchanges data between the application and MPTCP between the fourth layer (transport layer) and the seventh layer (application layer) of the OSI reference model. For example, the API 152 holds information on the subflow sf of MPTCP, and holds information on the updated subflow sf when the information on the subflow sf is updated. Thereby, the application can refer to various data used by MPTCP.

Note that the API 152 retains data by including data relating to the application or MPTCP in the parameters of the program constituting the API 152. Programs and parameters related to the API 152 are held in the memory 102.

The MPTCP control unit 153 (153A, 153B) operates according to MPTCP in the fourth layer (transport layer) of the OSI reference model, and performs control related to MPTCP. For example, the MPTCP control unit 153 establishes or disconnects an MPTCP session subflow. That is, the MPTCP control unit 153 controls a plurality of subflows. The MPTCP control unit 153 monitors each subflow and determines whether or not the subflow is continuously established.

The TCP communication unit 154 communicates data via the subflow sf1 (TCP connection) under the control of the MPTCP control unit 153. The subflow sf1 is a route through the communication I / F 104A and the communication I / F 104B.

The TCP communication unit 155 communicates data via the subflow sf2 (TCP connection) under the control of the MPTCP control unit 153. The subflow sf2 is a route through the communication I / F 106A and the communication I / F 106B.

The application information includes, for example, an application identifier, communication source necessary for executing the application, and information on the IP address of the communication destination. The subflow information includes, for example, identification information of the own device, IP address information of the own device used for subflow communication, identification information of another device (communication partner), and information of the IP address of the other device used for subflow communication. ,including.

If the API 152 is absent, it is unknown because the information on the application side cannot be referred from the MPTCP side unless it is devised, and the information on the MPTCP side cannot be referred from the application side. On the other hand, the API 152 is arranged between MPTCP and the application and can be referred to each other, and can share application information and subflow information.

[Use Case]
Next, use cases of the communication system 10 will be described.

[Use Case 1]
In use case 1, FTP (File Transfer Protocol) is executed as an application. That is, the server 100B is an FTP server. In the case of FTP, a control port and a data port are established separately for the subflow. Here, it is assumed that a subflow sf11 described later includes a control port subflow sf11 and a data port subflow sf11. Further, it is assumed that the subflow sf21 described later includes a control port subflow sf21 and a data port subflow sf21.

FIG. 4 is a sequence diagram illustrating an operation example when the communication system 10 that does not include the API 152 executes FTP according to MPTCP.

In FIG. 4, in the mobile terminal 100A, it is assumed that the communication method of the communication I / F 104A is a wireless LAN communication method, and the communication method of the communication I / F 106A is a wireless WAN communication method. The communication I / F 104A uses the IP address “XX”, and the communication I / F 106A uses the IP address “YY”. In the server 100B, it is assumed that the communication method of the communication I / F 104B is a wireless LAN communication method, and the communication method of the communication I / F 106B is a wireless WAN communication method. The communication I / F 104B uses the IP address “X′X ′”, and the communication I / F 106B uses the IP address “Y′Y ′”.

First, when the input device of the mobile terminal 100A receives an input operation from a user for executing an application, the application control unit 151A starts executing the application. Input devices widely include input devices such as a keyboard, a mouse, a touch pad, a touch panel, various keys, and a microphone.

With the start of application execution, the MPTCP control units 153A and 153B start establishment of a session related to FTP (S11). At this time, the MPTCP control units 153A and 153B establish the control port subflow sf11 (an example of the subflow sf1 shown in FIG. 3) using the IP addresses “XX” and “X′X ′” using the wireless LAN. To do.

Subsequently, the MPTCP control units 153A and 153B establish a subflow sf21 related to FTP in accordance with MPTCP (S12). At this time, the MPTCP control units 153A and 153B establish the control port subflow sf21 (an example of the subflow sf2 shown in FIG. 3) using the IP addresses “YY” and “Y′Y ′” using the wireless WAN. To do.

When the control port subflows sf11 and sf21 are established, the TCP communication unit 154A transmits a transfer request for FTP-related data (FTP data) via the control port subflow sf11 (S13).

In the server 100B, the TCP communication unit 154B receives the FTP data transfer request from the mobile terminal 100A via the subflow sf11. Then, the TCP communication units 154A and 154B transfer FTP data via the data port subflow sf11 (S14). Also, the TCP communication units 155A and 155B transfer FTP data via the port subflow sf21 (S15). That is, the communication system 10 can transfer FTP data through a plurality of paths (multipath), and communication efficiency can be improved.

Here, during the transfer of FTP data in S14 and S15, the sub-flow sf11 of the control port and the data port is disconnected due to the mobile terminal 100A moving out of the communication range of the wireless LAN (S16), and then the wireless LAN Assume that communication is not possible. Even in this case, since the subflow sf21 of the control port and the data port remains, the MPTCP session continues even after the wireless LAN is out of the communication range.

FTP data transfer continues until there is no more data to be transferred. Therefore, even after the control port and data port subflow sf11 is disconnected, the TCP communication units 155A and 155B continue to transfer FTP data via the data port subflow sf21 (S17). This FTP data is normally received by the server 100B (Transfer Complete). On the other hand, FTP data is not transferred via the subflow sf11 of the data port.

When there is no data to be transferred from the portable terminal 100A to the server 100B, the connection of each subflow is disconnected. On the other hand, the session connection is continued without terminating the FTP session. Here, the subflow sf21 of the data port is closed by the end of transfer due to the absence of data to be transferred, but the connection of the subflow sf21 of the control port is continued.

When the next FTP data transfer request occurs after the series of FTP data transfer when the subflow sf11 is disconnected, the TCP communication unit 155A sends the request to the server 100B via the control port subflow sf21. The FTP data transfer request is transmitted (S18).

In the server 100B, when receiving the FTP data transfer request in S18, the TCP communication unit 155B attempts to transmit FTP response data corresponding to the transfer request via the subflow sf21 of the data port. However, since the transmission source is different between the previous (S13) transfer request and the current (S18) transfer request, the application control unit 151B determines that an FTP error has occurred.

The TCP communication unit 155B transmits an FTP error message as FTP response data via the control port subflow sf21 under the control of the MPTCP control unit 153 (S19). This error message includes “Bad IP Connecting” information. The information of “Bad IP Connecting” indicates that the transmission source is determined to be different and is rejected because a transfer request is made through another route.

That is, in FIG. 4, the first transfer request is made via the subflow sf11, and the second transfer request is made via the subflow sf21. Therefore, when the API 100B is not provided, the server 100B determines that an FTP data transfer request has been received from an IP address different from that at the time of establishing the FTP session (at the time of S13). Accordingly, the server 100B terminates the FTP session connection by the security check, and terminates the connection of each subflow.

5A to 5C are flowcharts showing an operation example when the communication system 10 including the API 152 executes FTP according to MPTCP. FIG. 5A shows an operation example on the MPTCP side. FIG. 5B shows an operation example related to subflow monitoring of the API 152 on the application side. FIG. 5C shows an operation example related to the security check on the application side.

5A to 5C, similarly to FIG. 4, in the portable terminal 100A, the communication method of the communication I / F 104A is a wireless LAN communication method, and the communication method of the communication I / F 106A is a wireless WAN communication method. Is assumed. The communication I / F 104A uses the IP address “XX”, and the communication I / F 106A uses the IP address “YY”. In the server 100B, it is assumed that the communication method of the communication I / F 104B is a wireless LAN communication method, and the communication method of the communication I / F 106B is a wireless WAN communication method. The communication I / F 104B uses the IP address “X′X ′”, and the communication I / F 106B uses the IP address “Y′Y ′”.

In FIG. 5A, first, when the input device of the mobile terminal 100A receives an input operation from the user for executing the application, the application control unit 151A starts executing the application.

On the MPTCP side, with the start of application execution, the MPTCP control units 153A and 153B start establishment of a session related to FTP. At this time, the MPTCP control units 153A and 153B establish the subflow sf11 (an example of the subflow sf1 shown in FIG. 3) using the IP addresses “XX” and “X′X ′” using the wireless LAN (S21). ).

Subsequently, the MPTCP control units 153A and 153B establish a subflow sf21 related to FTP according to MPTCP (S22). At this time, the communication I / F 106A and the communication I / F 106B establish a subflow sf21 (an example of the subflow sf2 shown in FIG. 3) using the wireless WAN and the IP addresses “YY” and “Y′Y ′”. To do.

The MPTCP control units 153A and 153B register the subflow information in the APIs 152A and 152B (S23). This subflow information includes information related to each subflow of the MPTCP session established between the mobile terminal 100A and the server 100B (for example, information on the IP addresses of the communication I / F units 104A, 104B, 106A, and 106B). For example, the subflow information includes IP addresses “XX” and “X′X ′” used for the subflow sf11 and IP addresses “YY” and “Y′Y ′” used for the subflow sf21. Each IP address information used for each subflow sf21 is held in association with each other.

In addition, when another subflow is generated, the MPTCP control units 153A and 153B similarly register the subflow information related to the subflow in the APIs 152A and 152B. When any subflow is deleted (for example, when the wireless LAN is out of communication range and the subflow is disconnected), the subflow information related to this subflow is deleted from the APIs 152A and 152B.

In FIG. 5B, the application control units 151A and 151B monitor the subflow information with reference to the APIs 152A and 152B (S24).

And application control part 151A, 151B determines whether the subflow information of API152A, 152B is updated (S25).

For example, when the mobile terminal 100A goes out of the wireless LAN communication range, the subflow sf11 is disconnected by MPTCP. Information on the IP address related to the disconnected subflow sf11 is deleted from the APIs 152A and 152B. For example, when the mobile terminal 100A newly enters the wireless LAN communication range, the subflow sf31 is added by MPTCP. Information on the IP address related to the added subflow sf31 is registered in the APIs 152A and 152B.

Application control units 151A and 151B update the subflow information (for example, IP address information recognized by the application as a communication destination) of the application when the subflow information of APIs 152A and 152B has been updated (S26). The subflow information possessed by the application can be included, for example, as parameter information of the application program.

For example, in S23, the IP addresses “YY” and “Y′Y ′” used for the subflow sf21 are held in the APIs 152A and 152B as the subflow information. When the IP addresses “XX” and “X′X ′” related to the subflow sf11 are specified as communication destinations before the change, the application control units 151A and 151B refer to the subflow information of the APIs 152A and 152B to obtain the IP It is recognized that “YY” and “Y′Y ′” can be used instead of “XX” and “X′X ′” as addresses. Therefore, the application control units 151A and 151B update the application so that the IP addresses “YY” and “Y′Y ′” related to the changed subflow sf21 are communication destinations.

When the subflow information included in the application is updated in S26, the application control units 151A and 151B can communicate FTP data using the updated subflow information. In this case, for example, when the server 100B receives the FTP data transfer request as in S18 of FIG. 4, the application control unit 151B causes the IP address (for example, IP addresses “YY”, “Y ′”) of the updated subflow information. Assuming that Y ′ ”) is the IP address of the normal transfer request source, the FTP security check is performed. As a result, even if the server 100B receives a new transfer request after updating the subflow of the application, the server 100B can avoid an error that is determined as another path in the FTP security check, and suppresses the FTP communication from being stopped. it can.

In FIG. 5C, the application control unit 151B performs a security check related to FTP (S27). At the start of FIG. 5C, “YY” and “Y′Y ′” related to the updated subflow information are registered in the subflow information held by the API 152B. In addition, IP addresses “XX” and “X′X ′” are registered as communication destinations in the subflow information included in the IP address application.

The application control unit 151B determines whether a security check related to the application has occurred during execution of the application (S28). The security check occurs, for example, when the transfer request is acquired from another route (different subflow) due to the mobile terminal 100A moving out of the wireless LAN communication range. For example, it is conceivable that the subflow sf11 is disconnected when it is out of the communication range of the wireless LAN, and the subflow sf21 is established and maintained.

When a security check occurs, the application control unit 151B refers to the subflow information held in the API 152B (S29). As described above, the updated subflow information of the API 152B includes, for example, IP addresses “YY” and “Y′Y ′” used for the subflow sf21.

The application control unit 151B determines whether or not the security check error is resolved by replacing the IP address related to the subflow included in the application with another IP address included in the subflow information held in the API 152B ( S30). For example, the application control unit 151B sets the IP addresses “YY” and “Y′Y ′” (IP address of the current transfer request) in error to “XX” and “X′X ′” (the previous transfer request It is determined whether there is no security check error by replacing with (IP address).

When the security check error can be resolved by replacing the IP address, the application control unit 151B determines that the IP address of the subflow (subflow sf22 in this case) in error (here, IP address “YY”, “Y′Y ′”) Are excluded from security check targets (S30A).

To exclude from the security check target, an IP address (for example, IP address “XX”, “X′X ′”) related to the subflow possessed by the application is replaced with another IP address (for example, IP address included in the subflow information held in the API 152B). IP address “YY”, “Y′Y ′”) may be included.

Thereby, for example, the server 100B can rewrite the IP address that has become the transmission source of the previous transfer request, and the transmission source of the previous transfer request matches the transmission source of the current transfer request. Communication errors can be avoided.

In addition, excluding from the security check target includes the IP address (for example, IP address “XX”, “X′X ′”) that causes an error in the subflow information that the application has, and the source of the current transfer request. The application may hold information (for example, a flag) for excluding an IP address (for example, IP addresses “YY”, “Y′Y ′”) from the target of “Bad IP Connecting”.

Thereby, for example, the server 100B can avoid a communication error related to the security check even if the IP addresses related to the subflows of the transmission source of the previous transfer request and the transmission source of the current transfer request remain inconsistent. Further, since the server 100B can grasp the IP address of the transmission source of the current transfer request, the FTP data corresponding to the transfer request using this IP address (for example, IP addresses “YY”, “Y′Y ′”). Can be transferred and communication can be continued.

As described above, when executing FTP according to MPTCP, the communication apparatus 100 can update the subflow information of the application by referring to the API 152. The communication apparatus 100 communicates by using the updated subflow information, or excludes the IP address related to the subflow information that is not recognized by the application but registered in the API 152 from the security check target. It is possible to suppress the occurrence of an error and improve communication efficiency. Moreover, since the communication apparatus 100 can communicate using a plurality of subflows by MPTCP, communication can be speeded up if communication is possible in each subflow.

[Use Case 2]
In use case 2, AMQP (Advanced Message Queuing Protocol) is executed as an application. That is, the server 100B is an AMQP server.

FIG. 6 is a sequence diagram showing an operation example when the communication system 10 without the API 152 executes AMQP according to MPTCP.

In FIG. 6, it is assumed that in the portable terminal 100A, the communication method of the communication I / F 104A is a wireless LAN communication method, and the communication method of the communication I / F 106A is a wireless WAN communication method. The communication I / F 104A uses the IP address “XX”, and the communication I / F 106A uses the IP address “YY”. In the server 100B, it is assumed that the communication method of the communication I / F 104B is a wireless LAN communication method, and the communication method of the communication I / F 106B is a wireless WAN communication method. The communication I / F 104B uses the IP address “X′X ′”, and the communication I / F 106B uses the IP address “Y′Y ′”.

First, when the input device receives an input operation for executing an application, the application control units 151A and 151B start executing the application.

As the application starts, in the mobile terminal 100A, the TCP communication unit 154A opens the communication I / F 104A as a port (port open) and opens the communication I / F 104B (port) under the control of the MPTCP control unit 153A. open) (S31).

In the server 100B, the TCP communication unit 154B receives the port open request. The TCP communication unit 154B opens the communication I / F 104B as a port under the control of the MPTCP control unit 153B, and returns an ACK for the port open request (S32). As a result, the MPTCP control units 153A and 153B establish an AMQP session and establish a subflow sf12 (an example of the subflow sf1 illustrated in FIG. 3).

Similarly, under the control of the MPTCP control unit 153A, the TCP communication unit 155A requests the communication I / F 106A as a port to be opened (port open), the communication I / F 106B to be opened, and the addition of a subflow (Subflow JOIN) Is requested to the server 100B (S33).

In the server 100B, the TCP communication unit 155B receives the port open request and the Subflow JOIN request. The TCP communication unit 155B opens the communication I / F 106B as a port under the control of the MPTCP control unit 153B, establishes a new subflow sf22 (an example of the subflow sf2 shown in FIG. 3), and returns an ACK for the Subflow JOIN request. (S34).

Through S31 to S34, an MPTCP session is established, subflows sf12 and sf22 are established, and communication between the mobile terminal 100A and the server 100B is possible via multipath.

The TCP communication units 154A and 154B communicate data related to AMQP (AMQP data) via the established subflow sf12 (S35). The TCP communication units 155A and 155B communicate AMQP data via the established subflow sf22 (S36).

AMQP data includes, for example, subscription information and callback information. The subscription information includes subflow information (for example, identification information of the own device, identification information of the other device, IP address information of the own device relating to the subflow, information of the IP address of the other device relating to the subflow) and a callback function. This includes information on the conditions. Callback information is information relating to a callback function. The callback function is a function for the server 100B to send data to the mobile terminal 100A when various events occur (for example, when data to be transferred to the mobile terminal 100A or the server 200 occurs). By registering subscription information and callback information in the memory 102 of the server 100B, data can be transmitted from the server 100B to the mobile terminal 100A when an event occurs.

When there is no more AMQP data to be transmitted between the mobile terminal 100A and the server 100B, in the mobile terminal 100A, the TCP communication unit 154A closes the communication I / F 104A as a port (port close) under the control of the MPTCP control unit 153A. ) And request to open the communication I / F 104B (port close) (S37).

In the server 100B, the TCP communication unit 154B receives the port close request. The TCP communication unit 154B closes the communication I / F 104B as a port under the control of the MPTCP control unit 153B, and returns an ACK for the port close request (S38). As a result, the MPTCP control units 153A and 153B disconnect the AMQP subflow sf12.

Similarly, in the mobile terminal 100A, the TCP communication unit 155A requests the communication I / F 106A as a port to be closed (port close) and the communication I / F 106B to be closed (port close) under the control of the MPTCP control unit 153A. A request to disconnect the subflow is issued (S39).

In the server 100B, the TCP communication unit 155B receives the port close request and the subflow disconnection request. The TCP communication unit 155B closes the communication I / F 106B as a port under the control of the MPTCP control unit 153B, and returns an ACK for the port close request (S40). As a result, the MPTCP control units 153A and 153B disconnect the AMQP subflow sf22.

Here, it is assumed that the sub-flow sf21 is disconnected due to the mobile terminal 100A moving out of the wireless LAN communication range during or after the communication of the AMQP data, and then the wireless LAN communication is impossible (S41).

After S41, it is assumed that an event relating to an application occurs in the server 100B in a state where messages are accumulated in the queue. In this case, the application control unit 151B sends a port open request to the IP address “XX” in order to send the accumulated message via the subflow sf21 based on the subscription information and callback information held in the memory 120. (S42).

The mobile terminal 100A cannot receive the port open request transmitted to the IP address “XX” because it is located outside the communication range of the wireless LAN communication. Therefore, the portable terminal 100A cannot respond to the port open request (S43).

That is, when the mobile terminal 100A moves out of the wireless LAN communication range after the communication I / F as a port related to the subflow is once closed, the server 100B transmits AMQP data to the mobile terminal 100A when the API 152B is not provided. Even if the user wants to do so, the communication I / F on the portable terminal 100A side cannot be opened (port open). Therefore, the server 100B cannot transfer the data stored in the queue to the mobile terminal 100A.

7A to 7C are flowcharts showing an operation example when the communication system 10 including the API 152 executes AMQP according to MPTCP. FIG. 7A shows an operation example on the MPTCP side. FIG. 7B shows an operation example related to subflow monitoring of the API 152 on the application side. FIG. 7C shows an operation example related to the communication system on the application side.

7A to 7C, similarly to FIG. 6, in the portable terminal 100A, the communication method of the communication I / F 104A is a wireless LAN communication method, and the communication method of the communication I / F 106A is a wireless WAN communication method. Is assumed. The communication I / F 104A uses the IP address “XX”, and the communication I / F 106A uses the IP address “YY”. In the server 100B, it is assumed that the communication method of the communication I / F 104B is a wireless LAN communication method, and the communication method of the communication I / F 106B is a wireless WAN communication method. The communication I / F 104B uses the IP address “X′X ′”, and the communication I / F 106B uses the IP address “Y′Y ′”.

7A, first, when the input device of the mobile terminal 100A receives an input operation from a user for executing an application, the application control unit 151A starts executing the application.

On the MPTCP side, with the start of application execution, the MPTCP control units 153A and 153B start establishment of a session related to AMQP. At this time, the MPTCP control units 153A and 153B establish the subflow sf12 (an example of the subflow sf1 illustrated in FIG. 3) using the IP addresses “XX” and “X′X ′” using the wireless LAN (S51). ).

Subsequently, the MPTCP control units 153A and 153B establish a subflow sf22 related to AMQP (an example of the subflow sf2 shown in FIG. 3) according to MPTCP (S52). At this time, the MPTCP control units 153A and 153B establish the subflow sf22 using the IP addresses “YY” and “Y′Y ′” using the wireless WAN.

The MPTCP control units 153A and 153B register the subflow information in the APIs 152A and 152B (S53). This subflow information includes information related to each subflow of the MPTCP session established between the mobile terminal 100A and the server 100B (for example, information on the IP addresses of the communication I / F units 104A, 104B, 106A, and 106B). For example, the subflow information includes IP addresses “XX” and “X′X ′” used for the subflow sf12 and IP addresses “YY” and “Y′Y ′” used for the subflow sf22. Each IP address information used for each subflow is held in association with each other.

In addition, when another subflow is generated, the MPTCP control units 153A and 153B similarly register the subflow information related to the subflow in the APIs 152A and 152B. When any subflow is deleted (for example, when the wireless LAN is out of communication range and the subflow is disconnected), the subflow information related to this subflow is deleted from the APIs 152A and 152B.

7B, the application control units 151A and 151B refer to the APIs 152A and 152B and monitor the subflow information (S54).

And application control part 151A, 151B determines whether the subflow information of API152A, 152B is updated (S55).

For example, when the mobile terminal 100A goes out of the communication range of the wireless LAN, the subflow sf12 is disconnected by MPTCP. The IP address information related to the disconnected subflow sf12 is deleted from the APIs 152A and 152B. For example, when the mobile terminal 100A newly enters the wireless LAN communication range, the subflow sf32 is added by MPTCP. Information of the IP address related to the added subflow sf32 is registered in the APIs 152A and 152B.

When the subflow information of the APIs 152A and 152B has been updated, the application control units 151A and 151B update the subflow information (for example, information on the IP address that the application recognizes as a communication destination) that the application has (S56). The subflow information possessed by the application can be included, for example, as parameter information of the application program.

For example, in S53, the IP addresses “YY” and “Y′Y ′” used for the subflow sf22 are held in the APIs 152A and 152B as the subflow information. When the IP addresses “XX” and “X′X ′” related to the subflow sf12 are specified as communication destinations before the change, the application control units 151A and 151B refer to the subflow information of the APIs 152A and 152B to obtain the IP It is recognized that “YY” and “Y′Y ′” can be used instead of “XX” and “X′X ′” as addresses. Therefore, the application control units 151A and 151B update the application so that the IP addresses “YY” and “Y′Y ′” related to the changed subflow sf22 are communication destinations.

In FIG. 7C, the application control units 151A and 151B perform the data communication availability check related to AMQP (S57). At the start of FIG. 7C, “YY” and “Y′Y ′” related to the updated subflow information are registered in the subflow information held by the API 152B. In addition, IP addresses “XX” and “X′X ′” are registered as communication destinations in the subflow information included in the application.

The application control unit 151B determines whether there is no response from the communication destination during execution of the application (S58). As a factor that there is no response from the communication destination, for example, it is considered that the wireless LAN is out of communication range.

If there is no response from the communication destination, the application control unit 151B refers to the subflow information held in the API 152 (S59). As described above, the updated subflow information of the API 152B includes, for example, IP addresses “YY” and “Y′Y ′” used for the subflow sf22.

The application control unit 151B determines whether it is possible to obtain a response from the communication destination by replacing the IP address related to the subflow possessed by the application with another IP address included in the subflow information held in the API 152B. (S60). For example, can the application control units 151A and 151B acquire data at the communication destination by replacing the IP addresses “XX” and “X′X ′” of the communication destination with “YY” and “Y′Y ′”? Determine whether or not.

When the response can be acquired at the communication destination by replacing the IP address, the application control unit 151B updates the transmission destination of the data (AMQP data) related to the application with reference to the API 152B. Specifically, the application control unit 151B rewrites the transmission destination of the data related to the application from the IP address “XX”, “X′X ′” to “YY”, “Y′Y ′” (S61). The data relating to the application includes, for example, a port open instruction.

When the subflow information (in this case, the transmission destination information related to the application) included in the application is updated in S56 or S61, the application control unit 151B communicates AMQP data using the updated subflow information. That is, as in S42 of FIG. 6, when the server 100B transmits AMQP data (for example, Port Open request), the application control unit 151B causes the IP addresses “YY” and “Y′Y ′” of the updated subflow information. To the portable terminal 100A via the subflow sf22. Thereby, server 100B can receive AMQP data in portable terminal 100A. Therefore, the server 100B can receive ACK data for AMQP data from the mobile terminal 100A, and can suppress communication of AMQP data from being stopped.

As described above, when AMQP is executed according to MPTCP, the communication apparatus 100 can update the subflow information of the application by referring to the API 152. The communication device 100 can suppress the occurrence of an error due to the reception failure at the transmission destination by performing communication using the updated subflow information, and the communication efficiency can be improved. Moreover, since the communication apparatus 100 can communicate using a plurality of subflows by MPTCP, communication can be speeded up if communication is possible in each subflow.

[Effects]
As described above, in the communication system 10, when the first subflow of MPTCP disappears, the application can grasp that the address to be used by the application has transitioned by referring to the API. Therefore, for example, disconnection of any subflow due to abnormality detection due to mismatch between a control port and an address port that may occur in FTP or AMQP can be excluded so as not to be treated as an abnormality on the application side. Therefore, the communication system 10 can suppress the disconnection of the MPTCP session and continue the communication.

In addition, in the case of an application using a callback function such as AMQP, it is possible to suppress the occurrence of a malfunction due to the disappearance of the call destination of the callback function specified when the MPTCP session and the subflow are established after the disappearance of the first subflow of MPTCP. . Specifically, MPTCP notifies the application of the disappearance of the first subflow to the application via the API when the first subflow disappears. As a result, the communication system 10 can reconcile the MPTCP session and the subflow, match the control port and the address port before the callback function is called, and suppress the occurrence of a malfunction.

Thus, the communication device 100 according to the present embodiment communicates with other communication devices 100 according to MPTCP. The communication apparatus 100 includes an application control unit 151 that controls applications, an MPTCP control unit 153 that controls at least two subflows of MPTCP, and at least two TCP communication units 154 that communicate data via subflows using IP addresses. , 155, and an API 152 that holds information of a subflow including an IP address used for the subflow. When the subflow is changed, the API 152 holds information on the changed subflow. The application control unit 151 refers to the changed subflow information.

The communication device 100 is, for example, a mobile terminal 100A or a server 100B. Another communication device 100 is a server 100B or a portable terminal 100A. The TCP communication units 154 and 155 are examples of communication units. The MPTCP control unit 153 is an example of a communication control unit. The API 152 is an example of an information holding unit.

Thus, the communication apparatus 100 can recognize the changed (for example, added or deleted) subflow information by the application control unit 151 referring to the MPTCP subflow information via the API 152. Therefore, the IP address of the communication source or communication destination can be recognized using the changed subflow information, and communication errors in the execution of the application can be suppressed. Further, since the communication device 100 can perform communication according to MPTCP, it can speed up communication.

Further, the application control unit 151 may update the subflow information included in the application with reference to the changed subflow information held by the API 152.

Thereby, the communication apparatus 100 can change the subflow information related to the application in accordance with the change of the subflow information of MPTCP. Therefore, the communication apparatus 100 can communicate according to MPTCP according to the surrounding communication environment and the radio wave situation where the communication apparatus 100 is placed.

Further, the TCP communication unit 154 or 155 may receive the transfer request. When the IP address of the transfer request source is different from the IP address related to the subflow information of the application, the application control unit 151 may exclude the IP address of the transfer request source from the security check target.

Thereby, when communication by some TCP communication units is disconnected, the communication device 100 can exclude the IP address related to the TCP communication unit from the security check target of the application. In this case, the communication apparatus 100 can continue communication through the subflow using the IP address that has received the transfer request. Therefore, the communication device 100 as the receiving side can suppress the occurrence of an error related to the application and can improve the communication efficiency.

In addition, when the application control unit 151 transmits the first data to the other communication apparatus 100 and does not receive the second data for the first data from the other communication apparatus 100, the application control unit 151 The data transmission destination may be changed to any one of the plurality of IP addresses related to the subflow information held by the API 152 except for the IP address related to the subflow that has not received the second data. The first data is, for example, a port open request. The second data is an ACK in response to the port open request.

Thus, the communication apparatus 100 can transmit data related to the application using a subflow other than the subflow that failed in data communication among the plurality of established subflows with reference to the API 152. Therefore, it is possible to prevent the data communication related to the application from being stopped, and to improve the communication efficiency of MPTCP.

Further, the application control unit 151 may execute an FTP application. Accordingly, the communication device 100 can suppress the occurrence of the error message “Bad IP Connecting” related to FTP even when some subflows are disconnected, improve the continuity of communication related to MPTCP, and improve communication efficiency. Can be improved.

Further, the application control unit 151 may execute an AMQP application. Thereby, the communication apparatus 100 can transmit the AMQP data stored in the queue to other communication apparatuses 100 using other subflows even when some of the subflows are disconnected. Therefore, the communication apparatus 100 can improve the continuity of communication related to MPTCP, and can improve the communication efficiency.

Also, the API 152 may be located between the application control unit 151 and the MPTCP control unit 153 in the OSI reference model hierarchy.

Thereby, the application control unit 151 and the MPTCP control unit 153 cannot directly refer to each other's data, but can refer to the data via the API 152. Therefore, one of the application control unit 151 and the MPTCP control unit 153 can perform application control and communication control in consideration of the other data of the application control unit 151 and the MPTCP control unit 153.

(Other embodiments)
As described above, the first embodiment has been described as an example of the technique in the present disclosure. However, the technology in the present disclosure is not limited to this, and can also be applied to embodiments in which changes, replacements, additions, omissions, and the like are performed.

In the first embodiment, it is exemplified that the communication device 100 includes the API 152, but other functions may be provided instead of the API 152. For example, as shown in FIG. 8, in the communication apparatus 100, the application control unit 151α (151αA, 151αB) may have a function of monitoring information related to MPTCP (MPTCP information monitoring function). That is, subflow information related to MPTCP included in the API 152 may be mounted on the application side, and the application control unit 151 may refer to information related to MPTCP state management (subflow information and the like). In this case, as compared with the case where the communication apparatus 100 includes the API 152, it is sufficient to deal with the application side, so that the processing load can be reduced.

In the first embodiment, the communication system 10 may be a system other than a data communication system that implements FTP or a robot control system that implements AMQP. For example, the communication system 10 may be a content distribution system or a monitoring system.

In the first embodiment, it is exemplified that the communication device 100 can communicate according to two communication methods, but communication may be possible according to two or more communication methods.

In the first embodiment, the CPU 101 has been described as an example, but a processor other than the CPU 101 may be used. The processor may be physically configured in any manner. Further, if a programmable processor is used, the processing contents can be changed by changing the program, so that the degree of freedom in designing the processor can be increased. The processor may be composed of one semiconductor chip or physically composed of a plurality of semiconductor chips. When configured by a plurality of semiconductor chips, each control of the first embodiment may be realized by separate semiconductor chips. In this case, it can be considered that a plurality of semiconductor chips constitute one processor. Further, the processor may be configured by a member (capacitor or the like) having a function different from that of the semiconductor chip. Further, one semiconductor chip may be configured so as to realize the functions of the processor and other functions.

This disclosure is useful for a communication apparatus, a communication method, and the like that allow an application to recognize changed TCP subflow information and suppress communication errors during execution of the application.

DESCRIPTION OF SYMBOLS 10 Communication system 100 Communication apparatus 100A Portable terminal 100B Server 101, 101A, 101B CPU
102, 102A, 102B Memory 103, 103A, 103B Communication control I / F
104, 104A, 104B Communication I / F
105, 105A, 105B Communication control I / F
106, 106A, 106B Communication I / F
151, 151A, 151B, 151α, 151αA, 151αB Application control unit 152, 152A, 152B API
153, 153A, 153B MPTCP control unit 154, 154A, 154B TCP communication unit 155, 155A, 155B TCP communication unit NT network

Claims (8)

A communication device that communicates with other communication devices according to MPTCP,
An application control unit for controlling the application;
A communication control unit for controlling at least two subflows of the MPTCP;
At least two communication units for communicating data via the subflow using an IP address;
An information holding unit for holding information on the subflow including an IP address used for the subflow;
With
When the subflow is changed, the information holding unit holds information on the changed subflow,
The application control unit refers to information on the changed subflow. The communication device according to claim 1,
The communication control device, wherein the application control unit refers to information on the changed subflow held by the information holding unit and updates information on the subflow held by the application. The communication device according to claim 1 or 2,
The communication unit receives a transfer request,
The application control unit excludes the IP address of the transmission source of the transfer request from the security check target when the IP address of the transmission source of the transfer request is different from the IP address related to the information of the subflow possessed by the application. Communication device. The communication device according to claim 2,
When the application control unit transmits the first data to the other communication device and does not receive the second data for the first data from the other communication device, the first application related to the application The data transmission destination is changed to any IP address excluding the IP address related to the subflow in which the second data is not received among the IP addresses related to the subflow information held by the information holding unit, Communication device. The communication device according to claim 3,
The application control unit is a communication device that executes an application of FTP (File Transfer Protocol). The communication device according to claim 4,
The application control unit is a communication device that executes an application of AMQP (Advanced Message Queuing Protocol). The communication device according to any one of claims 1 to 6,
The communication apparatus, wherein the information holding unit is an API (Application Programming Interface) located between the application control unit and the communication control unit in a hierarchy of an OSI reference model. A communication method for communicating according to MPTCP,
Controlling at least two subflows of the MPTCP using an IP address;
Holding the information of the subflow including the IP address used for the subflow in an information holding unit;
Communicate data via the subflow,
When the subflow is changed, the information holding unit stores information on the changed subflow,
A communication method in which an application control unit that controls an application refers to information on the changed subflow.

Images