JP6767693B2 - Communication device and communication method - Google Patents

Description

The present disclosure relates to communication devices and communication methods.

Conventionally, a communication device that communicates according to MPTCP (MultiPath TCP (Transmission Control Protocol)) is known. As this communication device, it is known that in P2P (Peer to Peer) communication, a receiving peer can transmit a local IP address and an IP address associated with a VPN to the transmitting side. It is also known that when MPTCP technology is used, a peer can transmit all of its available IP addresses to other peers (see, for example, Patent Document 1).

Special Table 2013-521677

In a conventional communication device, when a local IP address is assigned to a part of a plurality of communication interfaces, it may be difficult to establish a subflow of MPTCP using the communication interface to which the local IP address is assigned. ..

This disclosure has been made in view of the above circumstances, and even if a local IP address is assigned to a part of a plurality of communication interfaces, the MPTCP subflow is performed using the communication interface to which the local IP address is assigned. Provide a communication device and a communication method that can be established with high accuracy.

The communication device of the present disclosure is a communication device that communicates with another communication device according to MPTCP, and uses a processor that controls communication and a local IP address that is converted into a global IP address by an address translation server. It includes a first communication interface that communicates by a communication method and a second communication interface that communicates by a second communication method using a global IP address. The first communication interface communicates the first control data for establishing the MPTCP session and subflow under the control of the processor. The second communication interface, under the control of the processor, communicates the second control data for adding the MPTCP subflow after the communication of the first control data. In the communication of the first control data, a packet for establishing an MPTCP session is transmitted, an approval packet from another communication device is received, and then a packet for notifying the IP address is transmitted. The packet for notifying the IP address contains the information of the global IP address assigned to the second communication interface .

The communication method of the present disclosure includes a first communication interface that communicates by a first communication method using a local IP address that is converted into a global IP address by an address conversion server, and a second communication method that uses a global IP address. It is a communication method in a communication device which includes a second communication interface for communicating with the other communication device and communicates with another communication device according to MPTCP , and is a first communication method for establishing an MPTCP session and a subflow by the first communication interface. The control data of the above is communicated, and after the communication of the first control data, the second control data for adding the subflow of MPTCP is communicated by the second communication interface, and in the communication of the first control data, After sending a packet for establishing an MPTCP session and receiving an approval packet from another communication device, a packet for notifying the IP address is sent, and a packet for notifying the IP address is the second. Contains information on the global IP address assigned to the communication interface of .

According to the present disclosure, even when a local IP address is assigned to a part of a plurality of communication interfaces, a subflow of MPTCP can be established with high accuracy by using the communication interface to which the local IP address is assigned.

Schematic diagram showing a configuration example of the communication system according to the first embodiment Block diagram showing a configuration example of a communication device Flowchart showing an operation example of a communication device Configuration diagram for explaining the communication system according to the first communication example Sequence diagram showing an operation example of the communication system according to the first communication example Configuration diagram for explaining the communication system according to the first communication example Sequence diagram showing an operation example of the communication system according to the first communication example Sequence diagram showing the operation of the communication system according to the comparative example Schematic diagram for explaining a communication system in another embodiment

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanations of already well-known matters and duplicate explanations for substantially the same configuration may be omitted. This is to avoid unnecessary redundancy of the following description and to facilitate the understanding of those skilled in the art. It should be noted that the accompanying drawings and the following description are provided for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

(Background to obtain one form of this disclosure)
In a communication device that communicates according to MPTCP, when a global IP address is assigned to all of a plurality of communication interfaces, the communication device can notify another communication device as a communication destination of the global IP address. Therefore, another communication device can take the lead in establishing a subflow of MPTCP with the communication device.

On the other hand, when the IP address of the communication device is a local IP address, the NAT (Network Address Translation) server installed between the communication device and the other communication device converts this local IP address into a global IP address. To. Then, the communication device transmits data to another communication device using the converted global IP address.

The communication device of Patent Document 1 transmits its own available IP address to another communication device, but when its own IP address is a local IP address, the global IP address corresponding to the local IP address is NATed. It does not have a function to query the server. Therefore, in the communication device, the IP address that can be notified becomes the local IP address, and the global IP address cannot be notified to other communication devices, and the other communication device changes from the notified local IP address to the global IP address. I can't recognize the information. Therefore, other communication devices cannot voluntarily establish an MPTCP subflow with the communication device, and the accuracy of establishing the MPTCP subflow may decrease.

(First Embodiment)
[Configuration, etc.]
FIG. 1 is a schematic diagram showing a configuration example of the communication system 10 according to the first embodiment. The communication system 10 has a plurality of communication devices 100 (100A, 100B, ...). The plurality of communication devices 100 are connected via the network NT. The communication device 100 includes, for example, a PC (Personal Computer), a smartphone, a mobile phone, a server, a base station device, a repeater, a camera, and a robot. The repeater includes, for example, an AP (Access Point), a gateway device, and the like. The robot is, for example, a security robot.

In the communication system 10, each communication device 100 uses MPTCP to perform data communication.

The network NT may include a wireless network or a wired network. Further, 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.

In the communication system 10, the plurality of communication devices 100 communicate data via the network NT in accordance with MPTCP by a predetermined communication method. The communication device 100 communicates voice data, image data, control data, and the like. The plurality of communication devices 100 can communicate by a plurality of communication methods.

The communication methods include, for example, wired LAN communication, wireless LAN communication, USB (Universal Serial Bus) communication, DECT (Digital Enhanced Cordless Telecommunication), LTE (Long Term Evolution), LTE-Advanced, Bluetooth communication, and millimeter-wave communication. Includes the method of (registered trademark) communication.

FIG. 2 is a block diagram showing a configuration example of the communication device 100. The communication device 100 includes a main SoC (System on a Chip) 110, an SDRAM 120, a flash memory 130, a display 140, a power controller 150, a plurality of communication interfaces 160, a battery 180, and a DC power connector 190.

The plurality of communication interfaces 160 may include, for example, two communication interfaces 160a, 160b, three communication interfaces 160a, 160b, 160c, or may include four or more communication interfaces.

The main SoC110 is an integrated circuit that integrates components that realize various functions on a semiconductor chip, and includes a CPU 111 (Central Processing Unit), a BCU (Bus Control Unit) 112, and a network controller 113.

The CPU 111 performs various processes and controls in cooperation with the SDRAM 120 and the flash memory 130. Specifically, the CPU 111 realizes each function of the communication device 100 by executing a program held in the SDRAM 120 or the flash memory 130. This program includes, for example, an OS (Operating System), middleware, and an application.

The BCU 112 cooperates with the SDRAM 120 and the flash memory 130 to control data transmission / reception of various buses in the communication device 100.

The network controller 113 is connected to a plurality of communication interfaces 160 and the network controller 113. The network controller 113 controls communication with the network NT connected via each communication interface 160. Further, the network controller 113 controls communication related to MPTCP in cooperation with the CPU 111.

The bus 115 is a route for each component including the CPU 111, the BCU 112, the network controller 113, and the display 140 to exchange data.

The bus 116 is a route for each component including the CPU 111, the BCU 112, the SDRAM 120, and the flash memory 130 to exchange data.

The SDRAM 120 is an example of a primary storage device that holds various types of data.

The flash memory 130 is an example of a secondary storage device that holds various data and programs. The flash memory 130 holds, for example, the identification information that identifies each communication interface 160 and the information of the IP address (global IP address or local IP address) assigned to each communication interface 160 in association with each other.

A memory or storage medium other than the SDRAM 120 and the flash memory 130 may be provided. For example, the communication device 100 may include various RAMs, various ROMs, HDDs (Hard Disk Drives), or SSDs (Solid State Drives).

The display 140 includes, for example, an LCD (Liquid Crystal Display) or an organic EL (Electro Luminescence) display, and displays various data.

The power controller 150 is connected to the battery 180 and the DC power connector 190 to control the power supply. For example, the power controller 150 selects either the power from the battery 180 or the power from the DC power connector 19 as the power supplied to the main SoC 110.

The communication interface 160a communicates data with another communication device according to the first communication method (for example, LTE communication) under the control of the network controller 113. For example, a global IP address is assigned to the communication interface 160a as an IP address. The interface corresponds to, for example, a port.

Under the control of the network controller 113, the communication interface 160b performs data communication with another communication device according to a second communication method (for example, wireless LAN communication) different from the first communication method. For example, a local IP address is assigned to the communication interface 160a as an IP address.

The communication interface 160c, under the control of the network controller 113, communicates data with other communication devices according to a third communication method different from the first communication method and the second communication method. For example, a local IP address is assigned to the communication interface 160a as an IP address.

The battery 180 includes a secondary battery such as a lithium ion battery, and supplies power to the main SoC 110 under the control of the power controller 150.

The DC power connector 190 can be connected to an external DC power supply and supplies power to the main SoC 110 under the control of the power controller 150. Further, the DC power connector 190 may supply electric power to the battery 180 and charge the battery 180 under the control of the power controller 150.

It is sufficient that at least one of the plurality of communication devices 100 included in the communication system 10 includes a plurality of communication interfaces 160 corresponding to the plurality of communication methods. That is, the communication system 10 may include a communication device 100 including a single communication interface 160.

[Operation, etc.]
Next, the operation of the communication system 10 will be described. The communication device 100 as its own device may be referred to as a communication device 100A. Further, the communication device 100 as the communication partner of the own device may be referred to as another communication device 100B.

FIG. 3 is a flowchart showing an operation example of the communication device 100.

First, the CPU 111 determines whether or not there is communication data (for example, voice data, image data, control data) to be transmitted to the other communication device 100B (S101). If the communication data does not exist, the process of S101 is repeated.

When there is communication data to be transmitted to the other communication device 100B, the CPU 111 inputs the information of each IP address (global IP address or local IP address) of the plurality of communication interfaces 160 of the communication device 100 as its own device. , Obtained from the flash memory 130 (S102).

The CPU 111 determines whether or not the local IP address exists in the acquired IP address information (S103).

When a local IP address exists in S103, the network controller 113 controls data for establishing an MPTCP session from the communication interface 160 (for example, the communication interface 160b) to which the local IP address is assigned via the NAT server 200. Is transmitted to another communication device 100B (S104). In this case, the local IP address assigned to the communication interface 160b is converted into a global IP address by the NAT server 200, and control data is transmitted to another communication device 100B using the global IP address.

When the session is established by S104, the network controller 113 starts communication of communication data via the communication interface 160b (S105).

The CPU 111 determines whether or not another local IP address exists in the acquired IP address information (S106).

When another local IP address exists in S106, the network controller 113 communicates a JOIN message between the communication interface 160 (for example, the communication interface 160c) to which the local IP address is assigned and the other communication device 100B. (S107).

In S107, a JOIN message may be transmitted from the communication interface 160c to which the local IP address of the communication device 100 is assigned to the other communication device 100B, or the JOIN message may be transmitted from the other communication device 100B to the communication interface 160c of the communication device 100. May be sent. Then, the process proceeds to S106 again.

When the JOIN message is normally communicated, a subflow of MPTCP is established between the communication device 100 and the other communication device 100B. The communication device 100 and the other communication device 100 can communicate with each other via an established MPTCP subflow.

On the other hand, when the local IP address does not exist in S103, it means that the addresses of all the communication interfaces 160 are global IP addresses. The network controller 113 transmits control data for establishing a session from the communication interface 160 (for example, the communication interface 160a) to which the global IP address is assigned (S108).

When the session is established by S108, the network controller 113 starts communication of communication data via the communication interface 160a (S109).

After the processing of S109 or when there is no other local IP address in S106, the network controller 113 determines whether or not there is another global IP address (S110).

When another global IP address exists in S110, the network controller 113 communicates a JOIN message between the communication interface 160 to which the global IP address is assigned and the other communication device 100B (S111).

In S111, a JOIN message may be transmitted from the communication interface 160 to which the global IP address of the communication device 100 is assigned to the other communication device 100B, or the global IP address of the communication device 100 is assigned from the other communication device 100B. A JOIN message may be sent to the communication interface 160. Then, the process proceeds to S110 again.

When there is no other global IP address in S110, it means that the information of the IP address related to each communication interface 160 has already been notified to the other communication device 100B. The CPU 111 determines whether or not to terminate the MPTCP session (S112).

For example, if the communication data to be transmitted to the other communication device 100B remains, the session establishment is continued, so that the CPU 111 determines that the session is not terminated. For example, when all the communication data to be transmitted to the other communication device 100B has been communicated, the CPU 111 determines that the session is terminated and terminates the established MPTCP session.

Next, specific MPTCP communication by the communication system 10 will be described. Here, a first communication example and a second communication example are shown.

[First communication example]
FIG. 4 is a configuration diagram for explaining the communication system 10 according to the first communication example. In the first communication example, the communication device 100A includes two communication interfaces 160 (for example, communication interface 160a and communication interface 160b), and the other communication device 100B includes one communication interface. A local IP address is assigned to the communication interface 160b of the communication device 100A, and a global IP address is assigned to the communication interface 160a of the communication device 100A. The communication device 100A and the other communication device 100B are connected via the Internet NT1.

A NAT server 200 is arranged between the communication device 100A and the Internet NT1. The NAT server 200 translates the local IP address and the global IP address used by the communication device 100A. Further, the NAT server 200 holds a translation table having information on the association between the global IP address and the local IP address in a memory (not shown).

In the communication device 100A, the CPU 111 determines whether the IP addresses assigned to the two communication interfaces 160 are global IP addresses or local IP addresses. If a local IP address exists among the two IP addresses, a session is established between the communication device 100A and the communication device 100B using the communication interface 160 to which the local IP address is assigned, and the first subflow is performed. Establish.

The communication device 100A communicates communication data using the first connected communication interface 160, and transmits or receives a JOIN message to another communication device 100A using the unconnected communication interface 160. If the JOIN to the session by the JOIN message is successful, a second subflow is added between the two communication interfaces 160 of the communication device 100A and the one communication interface 160 of the other communication device 100B. As a result, the communication device 100A and the other communication device 100B can simultaneously communicate communication data via the first subflow and the second subflow.

In a state where a session including a plurality of subflows is established, one of the two communication interfaces 160a and 160b of the communication device 100A, the communication interface 160a or 160b, and one communication interface 160 of the other communication device 100B Even if the subflow between them is disconnected, the other subflow can continue. This is because the other communication device 100B can recognize the global IP address related to the communication interface 160 of the communication device 100A related to the undisconnected subflow. The global IP address related to the communication interface 160 of the communication device 100A may be the global IP address assigned to the communication interface 160, or the global IP address corresponding to the local IP address assigned to the communication interface 160. You may. Therefore, the session related to the established MPTCP is continued by the remaining subflow.

FIG. 5 is a sequence diagram showing an operation example of the communication system 10 according to the first communication example. In FIG. 5, it is assumed that the communication interface 160a communicates using the global IP address and the communication interface 160b communicates using the local IP address.

In FIG. 5, the communication interface 160a of the communication device 100A is described as "interface 1", the communication interface 160b of the communication device 100A is described as "interface 2", and the communication interface 160 of the other communication device 100B is described as "other interface". It is described as.

In the communication system 10, when establishing the MPTCP session, first, the communication interface 160b of the communication device 100A transmits a SYN + MP_CAPABLE packet to the communication interface 160 of the other communication device 100B via the NAT server 200 (T101).

The SYN + MP_CAPABLE packet includes a synchronization packet (SYN) and a packet (MP_CAPABLE) for establishing an MPTCP session. In addition, "MP" means that it relates to MPTCP.

When the communication interface 160 of the communication device 100B receives the SYN + MP_CAPABLE packet, the communication interface 160 transmits the SYN + ACK + MP_CAPABLE packet to the communication interface 160b of the communication device 100A via NAT200 (T102).

The SYN + ACK + MP_CAPAVE packet includes a synchronization packet (SYN), an authorization packet (ACK), and a packet for establishing a session (MP_CAPABLE).

When the communication interface 160b of the communication device 100A receives the SYN + ACK + MP_CAPABLE packet, it transmits the ACK + MP_ADD_ADDRESS packet to the communication interface 160 of the other communication device 100B via the NAT server 200 (T103).

The ACK + MP_ADD_ADDRESS packet includes an authorization packet (ACK) and a packet for notifying an IP address (MP_ADD_ADDRESS). The MP_ADD_ADDRESS packet includes information on an IP address (global IP address) assigned to another communication interface 160 (here, communication interface 160a).

When the communication interface 160 of the communication device 100B receives the ACK + MP_ADD_ADDRESS packet, an MPTCP session is established between the communication device 100A and the communication device 100B. Then, the subflow SF11 is established between the communication interface 160b of the communication device 100A and the communication interface 160 of the other communication device 100B. The network controller 113 causes the flash memory 130 to hold the information of the global IP address of the communication interface 160a of the communication device 100A included in the packet of MP_ADD_ADDRESS.

The communication interface 160b of the communication device 100A and the communication interface 160 of the communication device 100B communicate communication data via the established subflow SF11. For example, the communication interface 160b of the communication device 100A transmits communication data (data) via the subflow SF11 (T104). The communication interface 160 of the other communication device 100B receives the communication data via the subflow SF11 and transmits the ACK data for the communication data via the subflow SF11 (T105).

The communication interface 160a of the communication device 100A transmits a SYN + MP_JOIN packet to the communication interface 160 of the other communication device 100B using the global address (T106). The SYN + MP_JOIN packet includes a synchronization packet (SYN) and a packet for adding a subflow (MP_JOIN).

When the communication interface 160 of the other communication device 100B receives the SYN + MP_JOIN packet, it transmits the SYN + ACK + MP_JOIN packet to the communication interface 160a of the communication device 100A using the global address (T107). The SYN + ACK + MP_JOIN packet includes a synchronization packet (SYN), an authorization packet (ACK), and a packet for adding a subflow (MP_JOIN).

When the communication interface 160a of the communication device 100A receives the SYN + ACK + MP_JOIN packet, the communication interface 160a transmits the ACK + MP_JOIN packet to the communication interface 160 of the other communication device 100B (T108). The ACK + MP_JOIN packet includes an approval packet (ACK) and a packet for adding a subflow (MP_JOIN).

When the communication interface 160 of the communication device 100B receives the ACK + MP_JOIN packet, the subflow SF12 is established between the communication interface 160a of the communication device 100A and the communication interface 160 of the other communication device 100B. Therefore, there are two subflows of the session established between the communication device 100A and the other communication device 100B, the subflows SF11 and SF12. The communication interface 160a of the communication device 100A and the communication interface 160 of the communication device 100B communicate communication data via the established subflow SF12.

For example, the communication interface 160a of the communication device 100A transmits communication data (data) via the subflow SF12 (T109). The communication interface 160 of the other communication device 100B receives the communication data via the subflow SF12 and transmits the ACK data for the communication data via the subflow SF12 (T110). Since the subflows SF11 and SF12 can coexist, the communication system 10 can communicate communication data using a plurality of subflows SF11 and SF12.

According to such a first communication example, in the communication system 10, the communication device 100A connects to the other communication device 100B from the communication interface 160b to which the local IP address is assigned. Subsequently, the communication device 100A newly establishes a session subflow SF12 between the communication interface 160a to which the global IP address is assigned and the communication interface 160 of the other communication device 100B. As a result, the communication device 100A can communicate communication data with the other communication device 100B by different communication methods using the plurality of communication interfaces 160.

Although the T106 illustrates that the SYN + MP_JOIN packet is transmitted from the communication device 100A to the other communication device 100B, it may be transmitted from the other communication device 100B to the communication device 100A. In this case, the communication interface 160 of the other communication device 100B may refer to the flash memory 130 and transmit a SYN + MP_JOIN packet to the global IP address of the communication interface 160a of the communication device 100A notified by the packet of ADD_ADRRESS. ..

When a SYN + MP_JOIN packet is transmitted from the communication device 100A to another communication device 100B as in T106, the other communication device 100B does not need to recognize the global IP address of the communication interface 160a of the communication device 100A in advance. , ADD_ADRRESS packet transmission may be omitted. That is, the communication of T103 may be omitted. Even in this case, if the communication device 100A responds with ACK data to the MP_CAPABLE packet from the other communication device 100B, the MPTCP session is established.

[Second communication example]
FIG. 6 is a configuration diagram for explaining the communication system 10 according to the second communication example. In the second communication example, the communication device 100A includes three communication interfaces 160 (for example, communication interfaces 160a, 160b, 160c), and the other communication device 100B includes one communication interface 160. Of the three communication interfaces 160a to 160c, the communication interfaces 160b and 160c are assigned local IP addresses, and the communication interfaces 160a are assigned global IP addresses. The communication device 100A and the other communication device 100B are connected via the Internet NT1.

A NAT server 200B is arranged between the communication device 100A and the Internet NT1 in the communication path used by the communication interface 160b. A NAT server 200C is arranged between the communication device 100A and the Internet NT1 in the communication path used by the communication interface 160c.

The NAT server 200B translates the global IP address and the local IP address used by the communication interface 160b of the communication device 100A. The NAT server 200C translates the global IP address and the local IP address used by the communication interface 160c of the communication device 100A. Further, the NAT servers 200B and 200C hold a translation table having information on the association between the global IP address and the local IP address in a memory (not shown).

In the communication device 100A, the CPU 111 determines whether the IP addresses assigned to the three communication interfaces 160a to 160c are global IP addresses or local IP addresses, respectively. If a local IP address exists among the three IP addresses, a session is established between the communication device 100A and the communication device 100B using the communication interface 160 to which the local IP address is assigned, and the first subflow is performed. Establish.

The communication device 100A communicates communication data using the first connected communication interface 160, and transmits or receives a JOIN message to another communication device 100A using the two unconnected communication interfaces 160. If the JOIN to the session by the JOIN message is successful, a second subflow and a third subflow are added between the three communication interfaces 160a to 160c of the communication device 100A and one communication interface 160 of the other communication device 100B. Will be done. As a result, the communication device 100A and the other communication device 100B can simultaneously communicate communication data via the first to third subflows. In the communication of the two JOIN messages, the communication of the JOIN message using the local IP address is carried out before the communication of the JOIN message using the global IP address.

In a state where a session including a plurality of subflows is established, communication between one of the three communication interfaces 160a to 160c of the communication device 100A, the communication interface 160a, 160b, or 160c, and one of the other communication devices 100B. Even if the subflow to and from the interface 160 is disconnected, the remaining two subflows can continue. This is because the other communication device 100B can recognize the global IP address related to the communication interface 160 of the communication device 100A related to the two undisconnected subflows. The global IP address related to the communication interface 160 of the communication device 100A may be the global IP address assigned to the communication interface 160, or may be the global IP address corresponding to the local IP address assigned to the communication interface 160. You may. Therefore, the session relating to the established MPTCP is continued.

FIG. 7 is a sequence diagram showing an operation example of the communication system 10 according to the second communication example. Here, it is assumed that the communication interface 160a communicates using the global IP address, and the communication interfaces 160b and 160c communicate using the local IP address.

In FIG. 7, the communication interface 160a of the communication device 100A is described as "interface 1", the communication interface 160b of the communication device 100A is described as "interface 2", and the communication interface 160c of the communication device 100A is described as "interface 3". The communication interface 160 of the other communication device 100B is described as "another interface". Further, the NAT server 200B is described as "NAT1", and the NAT server 200C is described as "NAT2".

In the communication system 10, when establishing the MPTCP session, first, the communication interface 160b of the communication device 100A transmits a SYN + MP_CAPABLE packet to the communication interface 160 of the other communication device 100B via the NAT server 200B (T201).

When the communication interface 160 of the communication device 100B receives the SYN + MP_CAPABLE packet, it transmits the SYN + ACK + MP_CAPABLE packet to the communication interface 160b of the communication device 100A via the NAT200B (T202).

When the communication interface 160b of the communication device 100A receives the SYN + ACK + MP_CAPABLE packet, it transmits the ACK + MP_ADD_ADDRESS packet to the communication interface 160 of the other communication device 100B via the NAT server 200B (T203).

The MP_ADD_ADDRESS packet contains, for example, information on a global IP address assigned to another communication interface (eg, communication interface 160a). The information of the local IPP address such as the IP address of the communication interface 160c does not have to be included in the packet of MP_ADD_ADDRESS.

When the communication interface 160 of the communication device 100B receives the ACK + MP_ADD_ADDRESS packet, a session is established between the communication device 100A and the communication device 100B. Then, the subflow SF21 is established between the communication interface 160b of the communication device 100A and the communication interface 160 of the other communication device 100B. The network controller 113 causes the flash memory 130 to hold the information of the global IP address of the communication interface 160a of the communication device 100A included in the packet of MP_ADD_ADDRESS.

The communication interface 160b of the communication device 100A and the communication interface 160 of the communication device 100B communicate communication data via the established subflow SF21. For example, the communication interface 160b of the communication device 100A transmits communication data (data) via the subflow SF21 (T204). The communication interface 160 of the other communication device 100B receives the communication data via the subflow SF21 and transmits the ACK data for the communication data via the subflow SF21 (T205).

The communication interface 160c of the communication device 100A transmits a SYN + MP_JOIN packet to the communication interface 160 of the other communication device 100B via the NAT server 200C (T206).

The communication interface 160 of the other communication device 100B receives the SYN + MP_JOIN packet, and transmits the SYN + ACK + MP_JOIN packet to the communication interface 160c of the communication device 100A via the NAT server 200C (T207).

When the communication interface 160c of the communication device 100A receives the SYN + ACK + MP_JOIN packet, it transmits the ACK + MP_JOIN packet to the communication interface 160 of the other communication device 100B via the NAT20C (T208).

When the communication interface 160 of the communication device 100B receives the ACK + MP_JOIN packet, the subflow SF22 is established between the communication interface 160c of the communication device 100A and the communication interface 160 of the other communication device 100B. The communication interface 160c of the communication device 100A and the communication interface 160 of the communication device 100B communicate communication data via the established subflow SF22.

For example, the communication interface 160c of the communication device 100A transmits communication data (data) via the subflow SF22 (T209). The communication interface 160 of the other communication device 100B receives the communication data via the subflow SF22 and transmits the ACK data for the communication data via the subflow SF22 (T210).

The communication interface 160a of the communication device 100A transmits a SYN + MP_JOIN packet to the communication interface 160 of the other communication device 100B using the global address (T211).

The communication interface 160 of the other communication device 100B receives the SYN + MP_JOIN packet and transmits the SYN + ACK + MP_JOIN packet to the communication interface 160a of the communication device 100A using the global address (T212).

When the communication interface 160a of the communication device 100A receives the SYN + ACK + MP_JOIN packet, it transmits the ACK + MP_JOIN packet to the communication interface 160 of the other communication device 100B (T213).

When the communication interface 160 of the communication device 100B receives the ACK + MP_JOIN packet, the subflow SF23 is established between the communication interface 160a of the communication device 100A and the communication interface 160 of the other communication device 100B. Therefore, there are three subflows of the session established between the communication device 100A and the other communication device 100B: subflows SF21, SF22, and SF23. The communication interface 160a of the communication device 100A and the communication interface 160 of the communication device 100B communicate communication data via the established subflow SF23.

For example, the communication interface 160a of the communication device 100A transmits communication data (data) via the subflow SF23 (T214). The communication interface 160 of the other communication device 100B receives the communication data via the subflow SF23 and transmits the ACK data for the communication data via the subflow SF23 (T215). Since the subflows SF21, SF22, and SF23 can coexist, the communication system 10 can communicate communication data using a plurality of subflows SF21, SF22, and SF23.

According to such a second communication example, in the communication system 10, the communication device 100A connects to the other communication device 100B from the communication interface 160b to which the local IP address is assigned. Subsequently, the communication device 100A newly establishes a session subflow between the communication interface 160c to which another local IP address is assigned and the communication interface 160 of the other communication device 100B. Subsequently, the communication device 100A newly establishes a session subflow between the communication interface 160a to which the global IP address is assigned and the communication interface 160 of the other communication device 100B. As a result, the communication device 100A can communicate communication data with the other communication device 100B by different communication methods using the plurality of communication interfaces 160.

Although the T211 illustrates that the SYN + MP_JOIN packet via the communication interface 160a is transmitted from the communication device 100A to the other communication device 100B, it may be transmitted from the other communication device 100B to the communication device 100A. In this case, the communication interface 160 of the other communication device 100B may refer to the flash memory 130 and transmit a SYN + MP_JOIN packet to the global IP address of the communication interface 160a of the communication device 100A notified by the packet of ADD_ADRRESS. ..

When a SYN + MP_JOIN packet is transmitted from the communication device 100A to another communication device 100B as in T211, the other communication device 100B does not need to recognize the global IP address of the communication interface 160a of the communication device 100A in advance. , ADD_ADRRESS packet transmission may be omitted. That is, the communication of T103 may be omitted. Even in this case, if the communication device 100A responds with ACK data to the MP_CAPABLE packet from the other communication device 100B, the MPTCP session is established.

On the other hand, in T206, the SYN + MP_JOIN packet via the communication interface 160c needs to be transmitted from the communication device 100A to another communication device 100B. This is because even if the local IP address of the communication interface 160c of the communication device 100A is notified by the packet of ADD_ADRRESS, the other communication device 100B cannot access the communication device using the local IP address.

In FIG. 7, the subflow SF22 using the communication interface 160c is established before the subflow SF23 using the communication interface 160a, but the order of establishing the subflows may be reversed. This is because the global IP address assigned to the communication interface 160a can be notified by the subflow SF21 using the communication interface 160b established first.

[Communication priority setting]
Next, the priority of communication in the case of MPTCP communication using a plurality of local IP addresses as in the second communication example will be described.

The communication priority by the communication device 100A here indicates the order in which each communication interface 160 transmits control data for establishing a session or subflow to another communication device 100B. The control data for establishing a session includes, for example, a SYN + MP_CAPABLE packet. The control data for establishing the subflow includes, for example, a SYN + MP_CAPABLE packet and a SYN + MP_JOIN packet.

The CPU 111 may set the communication priority, for example, based on the type of the communication interface 160. For example, in the case of communication using the communication interface 160 that does not use the global IP address, the communication priority is set higher in the order of wired LAN communication, wireless LAN communication, and cellular communication. The set communication priority information is held in the flash memory 130. Based on the communication priority information held in the flash memory 130, the CPU 111 transmits control data in order from the communication interface 160 having the highest communication priority.

The CPU 111 may determine the communication priority, for example, based on the bandwidth thickness of each subflow via each communication interface 160. The CPU 111 may set the communication priority in descending order of the bandwidth of each subflow. For example, the CPU 111 may have higher communication priorities in the order of wired LAN communication, wireless LAN communication, and cellular communication (for example, LTE communication).

The CPU 111 may estimate the band of each subflow by a known band estimation method. Further, the CPU 111 may transmit PING to acquire information on the delay time. The CPU 111 may set the communication priority higher as the delay time is shorter. Further, the CPU 111 may estimate the bandwidth of the subflow by using the bandwidth estimation packet.

The communication device 100A can speed up communication by communicating communication data using a communication interface 160 of a communication method corresponding to the communication priority based on the communication priority. Further, according to MPTCP, communication can be speeded up by increasing the amount of communication data in a subflow having a large band and decreasing the amount of communication data in a subflow having a narrow band. The CPU 111 may distribute the communication data to each subflow so that the order in which the communication data should arrive does not change. For example, the communication interface 160 may transmit image data requiring high speed in a subflow of a thick band and control data not requiring high speed in a subflow of a thin band under the control of the network controller 113.

In the above, the communication priority using the local IP address when there are multiple local IP addresses has been described, but the communication priority using the global IP address when there are multiple global IP addresses may be applied. Good. However, local communication is prioritized between communication using a communication interface using a local IP address (local communication) and communication using a communication interface using a global IP address (global communication).

It should be noted that any communication interface 160 may be randomly selected without setting the communication priority of the plurality of communication interfaces 160.

[Retransmission control]
Next, retransmission control in MPTCP communication will be described.

Suppose any subflow is disconnected after a session containing multiple subflows is established. For disconnection of the subflow, for example, deterioration of the radio wave condition of wireless LAN communication can be considered. When any subflow is disconnected, if communication data is communicated using this subflow, this communication data does not reach the other communication device 100B. The communication device 100 can recognize that the subflow is disconnected by not receiving the ACK data for the communication data within a predetermined time. In this case, the network controller 113 communicates communication data via the continuously established subflow instead of the disconnected subflow. Therefore, the communication device 100A can assist the communication via the disconnected subflow by using another subflow.

[Effects, etc.]
Since the communication device 100A does not have a function of querying the global IP address for the NAT server 200, the global IP address corresponding to the local IP address assigned to the communication interfaces 160b and 160c of the communication device 100A cannot be identified. Therefore, the communication device 100A cannot notify ADD_ADDRESS including the global IP address corresponding to the local IP address, and notifies ADD_ADDRESS including the local IP address. Therefore, the other communication device 100B acquires the information of the local IP addresses of the communication interfaces 160b and 160c of the communication device 100A. In the other communication device 100B, the transmission destination on the network NT cannot be specified by the local IP address, and the communication data cannot be transmitted.

FIG. 8 is a diagram showing a comparative example in which communication data cannot be communicated from such a communication device as another device to a communication device as its own device. In FIG. 8, the communication interface 1 using the global IP address of the own device starts the MPTCP session establishment by the packet of MP_CAPABLE, and notifies the local IP address of the communication interface 2 by the packet of MP_ADD_ADRESS. In this case, even if the other device accesses the own device using the notified local IP address by the packet of MP_JOIN and tries to add the subflow, the packet does not reach the own device and the communication is not established.

On the other hand, the communication device 100 of the present embodiment communicates with another communication device 100 according to MPTCP. The communication device 100 uses a processor that controls communication, a local IP address that is translated into a global IP address by the NAT server 200, a communication interface 160b that communicates by the first communication method, and a global IP address. It includes a communication interface 160a that communicates by the second communication method. The communication interface 160b communicates a SYN + MP_CAPABLE packet or a SYN + ACK + MP_CAPABLE packet for establishing an MPTCP session and subflow under the control of a processor. The communication interface 160a communicates the SYN + MP_JOIN packet and the SYN + ACK + MP_JOIN packet for adding the subflow of MPTCP after the communication of the MP_CAPABLE packet under the control of the processor.

The communication device 100 is a communication device 100A or a communication device 100B. The other communication device 100 is a communication device 100B or a communication device 100A. The NAT server 200 is an example of an address translation server. The SYN + MP_CAPABLE packet and the SYN + ACK + MP_CAPABLE packet are examples of the first control data. The SYN + MP_JOIN packet and the SYN + ACK + MP_JOIN packet are examples of the second control data. Processors include, for example, CPU 111 or network controller 113. The communication interface 160b is an example of the first communication interface. The communication interface 160a is an example of the second communication interface.

As a result, even if a local IP address is assigned to a part of the plurality of communication interfaces 160, the communication device 100 can perform a session between the communication interface 160 to which the local IP address is assigned and another communication device 100. Communicate (transmit or receive) control data for establishing a subflow. Therefore, the other communication device 100 can recognize the global IP address corresponding to the local IP address assigned to the communication interface 160b of the communication device 100.

Therefore, the communication system 10 can establish an MPTCP session between the communication device 100 and another communication device 100, and can establish a plurality of subflows. By establishing a plurality of subflows, the communication system 10 can speed up communication.

Further, in the communication system 10, even if one of the subflows is disconnected during the communication, the other subflows are maintained, so that the MPTCP session can be continued and the communication can be continued. For example, the communication device 100 can continue the subflow for performing LTE communication via the communication interface 160a even if the radio wave of the wireless LAN communication by the communication interface 160b becomes poor and the subflow via the communication interface 160b is disconnected.

Further, the communication device 100 may include a plurality of communication interfaces 160b and 160c that communicate using a local IP address. Of these communication interfaces 160, the communication interface 160c that does not communicate with the MP_CAPABLE packet may communicate with the SYN + MP_JOIN packet or the SYN + ACK + MP_JOIN packet for adding the MPTCP subflow after the MP_CAPABLE packet is communicated under the control of the processor. .. The SYN + MP_JOIN packet and the SYN + ACK + MP_JOIN packet here are examples of the third control data. The communication interface 160c is an example of a third communication interface.

When MPTCP communication is performed using a plurality of local IP addresses, it is difficult to notify the global IP address corresponding to the local IP address by control data (for example, SYN + MP_ADD_ADDRESS packet). On the other hand, the communication device 100 requests the other communication device 100 to add a subflow using the second and subsequent local IP addresses, so that the other communication device 100 can use the local IP address of the communication device 100. Can recognize the translated global IP address. Therefore, if the other subflow is disconnected, the connection and maintenance of the second and subsequent subflows using the local IP address are maintained, and the communication device 100 and the other communication device 100 can communicate using this subflow.

Further, the processor may determine the order of establishing MPTCP subflows based on the communication methods of the communication interfaces 160b and 160c. The communication interfaces 160b and 160c may communicate the SYN + MP_CAPABLE packet, the SYN + ACK + MP_CAPABLE packet, the SYN + MP_JOIN packet, and the SYN + ACK + MP_JOIN packet in the determined establishment order.

As a result, the communication device 100 can establish a subflow of MPTCP using a local IP address according to the characteristics of the communication method. For example, the communication device 100 can improve the stability of the communication connection and quickly realize the stable MPTCP communication by preferentially establishing the subflow using the wired communication. Further, the communication device 100 can reduce the traffic volume of communication using an external network (for example, the Internet NT1) by preferentially establishing a subflow using LAN communication, and can effectively utilize the network.

Further, the processor may determine the order of establishing MPTCP subflows based on the communication band used for communication by the communication interfaces 160b and 160c. The communication interfaces 160b and 160c may communicate the SYN + MP_CAPABLE packet, the SYN + ACK + MP_CAPABLE packet, the SYN + MP_JOIN packet, and the SYN + ACK + MP_JOIN packet in the determined establishment order.

As a result, the communication device 100 can establish a subflow capable of high-speed MPTCP communication using the local IP address. Therefore, the communication device 100 can secure a wide band capable of rapid communication, and can realize further speeding up of MPTCP communication.

Further, the communication interfaces 160a to 160c may retransmit the communication data via the other subflows when a part of the established subflows is disconnected.

As a result, the communication device 100 can retransmit the communication data to be sent by the disconnected subflow even when the subflow of either the local IP address or the MPTCP using the global IP address is disconnected. Therefore, the communication device 100 can improve the reliability of MPTCP communication.

Further, the communication interface 160b may transmit an MP_ADD_ADDRESS packet including information on the global IP address of the communication interface 160a. The MP_ADD_ADDRESS packet is an example of the fourth control data.

As a result, the other communication device 100 can recognize the information of the global IP address of the communication device 100. Therefore, a new subflow using the global IP address can be added from the other communication device 100 to the communication device 100. Can be established.

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

In the first embodiment, it is illustrated that the communication device 100A includes a plurality of communication interfaces 160 and the other communication device 100B includes one communication interface 160, but the other communication device 100B includes a plurality of communication interfaces 160. You may prepare.

FIG. 9 is a schematic diagram for explaining a communication system according to another embodiment. In FIG. 9, the communication device 100A includes m (m is an arbitrary number) communication interfaces 160, and the other communication device 100B includes n communication interfaces 160 (n is an arbitrary number). In this case, m × n subflows can be established.

Further, in FIG. 9, the other communication device 100B illustrates that the global IP address is used in all the communication interfaces 160, but a part of these communication interfaces 160 may use the local IP address. .. In this case, the NAT server 200 is arranged between the Internet NT1 and the other communication device 100B as in the communication device 100A side.

In the first embodiment, the NAT server 200 is used to translate the local IP address and the global IP address, but the address translation may be performed by another method. For example, instead of the NAT server 200, the address may be translated by using a NAPT (Network Addless Port Translation) server that adds port information in addition to the address information. By using a NAT server, one global IP address and a plurality of local IP addresses can be translated.

In the first embodiment, the communication system 10 may be a wireless communication system including a base station, or another system (for example, a content distribution system or a monitoring system). In the case of a wireless communication system, the communication device 100A is, for example, a mobile terminal, and the communication device 100B is, for example, a base station device. In the case of a content distribution system, the communication device 100A is, for example, a mobile terminal, and the communication device 100B is, for example, a content distribution server. In the case of a monitoring system, the communication device 100A is, for example, a camera device, and the communication device 100B is, for example, a monitoring PC.

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

In the first embodiment, the CPU 111 and the network controller 113 have been described as an example, but a processor other than the CPU 111 and the network controller 113 may be used. The processor may be physically configured in any way. Further, if a programmable processor is used, the processing content can be changed by changing the program, so that the degree of freedom in processor design can be increased. The processor may be composed of one semiconductor chip, or may be physically composed of a plurality of semiconductor chips. When it is composed of a plurality of semiconductor chips, each control of the first embodiment may be realized by a separate semiconductor chip. In this case, it can be considered that one processor is composed of those plurality of semiconductor chips. Further, the processor may be composed of 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.

In the first embodiment, the configuration of the communication device 100 is shown in FIG. 2, but each configuration may be realized by hardware or software.

In the present disclosure, even when a local IP address is assigned to a part of a plurality of communication interfaces, a communication device and a communication method capable of establishing a subflow of MPTCP with high accuracy by using the communication interface to which the local IP address is assigned, etc. It is useful for.

10 Communication system 100, 100A, 100B Communication device 110 Main SoC
111 CPU
112 BCU
113 Network controller 120 SDRAM
130 Flash memory 140 Display 150 Power controller 160, 160a, 160b, 160c Communication interface 180 Battery 190 DC power connector 200, 200B, 200C NAT server NT network NT1 Internet

Claims (7)

A communication device that communicates with other communication devices according to MPTCP.
The processor that controls communication and
A first communication interface that communicates by the first communication method using a local IP address that is converted into a global IP address by an address translation server.
A second communication interface that communicates by the second communication method using the global IP address,
With
The first communication interface communicates the first control data for establishing the session and subflow of the MPTCP under the control of the processor.
Under the control of the processor, the second communication interface communicates the second control data for adding the subflow of the MPTCP after the communication of the first control data .
In the communication of the first control data, a packet for establishing an MPTCP session is transmitted, an approval packet from the other communication device is received, and then a packet for notifying the IP address is transmitted.
The packet for notifying the IP address is a communication device including information on the global IP address assigned to the second communication interface . The communication device according to claim 1.
A plurality of the first communication interfaces are provided.
Among the first communication interfaces, the communication interface that does not communicate with the first control data is a third for adding the MPTCP subflow after the communication of the first control data under the control of the processor. A communication device that communicates control data. The communication device according to claim 2.
The processor determines the establishment order of the MPTCP subflows based on the communication method of each first communication interface.
Each first communication interface is a communication device that communicates the first control data or the third control data in the determined establishment order. The communication device according to claim 2.
The processor determines the establishment order of the MPTCP subflows based on the communication band used for communication by each first communication interface.
Each first communication interface is a communication device that communicates the first control data or the third control data in the determined establishment order. The communication device according to any one of claims 1 to 4.
The first communication interface or the second communication interface is a communication device that retransmits communication data via another subflow when a part of the established subflows is disconnected. The communication device according to claim 2.
The first communication interface is a communication device that transmits fourth control data including information on the global IP address of the second communication interface. A first communication interface that communicates by the first communication method using a local IP address that is converted into a global IP address by an address translation server, and a second communication that communicates by a second communication method using a global IP address. A communication method in a communication device having an interface and communicating with another communication device according to MPTCP.
By the first communication interface for communicating first control data for establishing a session and sub-flow of the MPTCP,
By the second communication interface, after the communication of the first control data, and communicates the second control data for adding subflow of the MPTCP,
In the communication of the first control data, a packet for establishing an MPTCP session is transmitted, an approval packet from the other communication device is received, and then a packet for notifying the IP address is transmitted.
A communication method in which a packet for notifying the IP address includes information on the global IP address assigned to the second communication interface .

Images