JP2006333080A - Mobile communication terminal, and method and program for communication path selection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication terminal having a plurality of communication paths connectable to a specified host, which is capable of automatically selecting a network path. <P>SOLUTION: The mobile communication terminal according to the present invention is provided with a function of determining a communication path in response to a DNS query of an application program. This function is embodied by providing a name solving means of returning a dummy address as an identifier for correspondence between a communication interface and a real address to the application program, a host name/interface conversion table for conversion between a host name and an interface, an interface determining means of selecting a communication interface when data are transmitted, and a dummy address/real address/interface correspondence table for solving the real address and communication interface from the dummy address. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a portable communication terminal, a communication route selection method, and a communication route selection program, and in particular, a portable communication capable of automatically selecting a network route in a portable communication terminal that can use a plurality of types of communication routes. The present invention relates to a terminal, a communication route selection method, and a network route selection program.

  In recent years, mobile communication terminals that have a plurality of communication interfaces such as a mobile phone network and a wireless LAN and can be used simultaneously have been realized. In addition, mobile communication terminals have a function of accessing a private network using a VPN or the like, and the means for connecting to the network is becoming more sophisticated / complex.

  In such a mobile communication terminal having a plurality of communication interfaces, the user wants to automatically select and connect the communication interface most suitable for the service to be used.

  As a technique related to automatic selection of a communication interface, a communication path selection method for a mobile communication terminal having a plurality of communication paths disclosed in Technical Document 1 is known. The composite terminal device for wireless communication of Patent Document 1 is a mobile communication terminal that receives traffic information transmitted from a plurality of different wireless communication networks and automatically selects a communication interface with low traffic based on the received traffic information. is there.

  This technology merely selects a plurality of communication interfaces automatically according to traffic, and cannot preferentially connect to any one of the plurality of communication interfaces according to service contents.

  In addition, when a mobile communication terminal transmits a packet in a situation where it is simultaneously connected to both of a plurality of communication interfaces, the transmission communication interface is determined only by the routing table. If not described, the default communication interface is selected. However, when one or both communication interfaces are operated in a private network space, the default communication interface may not reach the network to be used correctly.

  Even if the target network can be simultaneously reached from a plurality of communication interfaces, a network using only a routing table cannot automatically select a network with good response performance.

  A communication path selection system in which a plurality of networks are formed between a host and a terminal, and a network in which a failure has occurred is bypassed to connect the terminal to the host has been proposed as Patent Document 2. It is merely an option to select a network that can be connected from among a plurality of networks, and, like the above, it is preferentially connected to any one of a plurality of communication interfaces according to the service contents. It is not possible.

JP 2000-209644 A JP 2003-348134 A

  The problem with this type of prior art is that when a terminal connects to a network to which a service is provided (hereinafter, this network is referred to as a service network), there are a plurality of available communications, and the terminal is appropriately selected from these. When it is necessary to perform communication by selecting a communication path, there is no means for determining a communication path from a service to be used. The reason is that in the conventional method, the selection of the communication path is not determined from the service, but is fixed by the application to be used or determined only by the user operation.

  In addition, although a plurality of communication paths can be used at the same time, there is a problem that there is no means for automatically selecting a reachable communication path when there is only one communication path that can reach the host where the service is deployed. is there. The reason is that in the conventional method, the communication route to be used is fixedly set by a routing table or the like, and there is no means for confirming the reachability to the host and selecting a reachable one.

  In addition, when there are a plurality of communication paths that can reach the host where the service is deployed, there is a problem that there is no means for automatically selecting the communication path with the best conditions. This is because the conventional method does not have means for measuring the characteristics of the communication path to be used and selecting the best condition.

  Therefore, an object of the present invention is to improve the disadvantages of the prior art and automatically determine a communication path associated with a connection destination host name when a terminal having a plurality of communication paths connects to a service network. It is to provide means.

  In addition, when a terminal uses multiple communication paths at the same time, a means for automatically selecting a reachable one from among them, or when a terminal uses multiple communication paths at the same time, It is also a part of the object to provide a means for automatically selecting the one with good response performance from the above.

  The portable communication terminal, the communication route selection method, and the communication route selection program of the present invention achieve the above object by providing a function for determining a communication route according to a DNS query from an application program.

  In order to realize this function, in particular, name resolution means for returning a dummy address to an application program as an identifier for associating a communication interface as a communication path with a real address of a connection destination host, and a packet from the dummy address at the time of packet transmission And a means for determining a communication path for transmitting.

  Since a dummy address is used as an identifier for associating the communication interface that is the communication path with the real address of the connection destination host, the application program sets the correspondence between the communication interface and the real address of the connection destination host as a normal address. It can be handled in the same way as (IP address). For this reason, it is possible to accurately select the communication path (communication interface) corresponding to the connection destination host name without making any special modification to the application program.

  Specifically, the means for determining the communication path includes a storage means (host name / communication interface conversion table) for storing the connection destination host name and the communication path in association with each other, and an actual result obtained by the DNS query at the time of name resolution. A storage means (dummy address / communication interface correspondence database) for storing the communication path obtained from the address and the connection destination host name in association with the dummy address, and the real address and communication path from the dummy address given from the application program at the time of connection And determining means (interface determining means).

  Furthermore, a means (optimum interface search means) for determining a communication path with good communication performance by determining connection reachability to the connection destination at the time of a data transmission request and measuring communication performance to the connection destination is provided. Thus, a communication path (communication interface) that can reach the service network and has good response performance can be automatically selected.

  The portable communication terminal, the communication route selection method, and the communication route selection program of the present invention store the related information between the service and the communication route in the portable communication terminal so that the portable communication terminal having a plurality of communication routes can use the service. As the communication path is established by automatically selecting an appropriate communication path according to the request, it is possible to reduce the number of user operations when connecting the mobile communication terminal to the network. Improves.

  In addition, a dummy address having the same format as a normal IP address is used as an identifier for associating the communication interface that is the communication path and the real address of the connection destination host. By returning, the conventional API can be used as it is. For this reason, it is possible to realize automatic selection of a communication path according to a service use request without taking the cost and trouble of modifying a conventional application.

  Next, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  A mobile communication terminal according to an embodiment to which the present invention is applied will be described with reference to FIG. A detailed description of the internal configuration of the mobile communication terminal 1 is shown in FIG.

  The mobile communication terminal 1 includes an application program 101, a transmission processing unit 102, a name resolution unit 103, a host name / communication interface conversion table 104, an interface determination unit 105, a dummy address / communication interface correspondence database 106, a routing It comprises a table 107, communication interfaces 108 and 109 which are substantial communication paths, DNS query means 110, and an interface / DNS server correspondence table 111.

  Among these, the transmission processing unit 102, the name resolution unit 103, the interface determination unit 105, and the DNS query unit 110 are configured with a microprocessor mounted on the mobile communication terminal 1 as a function realizing unit, and a host name / communication interface conversion table. 104, the dummy address / communication interface correspondence database 106, the routing table 107, and the interface / DNS server correspondence table 111 are provided in a non-volatile storage unit of the mobile communication terminal 1.

  The application program 101 is an application program built in the mobile communication terminal 1 and performs various processes using information and services provided from an external http server or the like.

  The transmission processing unit 102 receives a data transmission request or a service connection request from the application program 101 and performs packet transmission processing.

  The name resolution unit 103 performs processing for obtaining a connection destination IP address based on a name such as a connection destination host name. The name resolution unit 103 according to the present embodiment includes the normal address of the connection destination host obtained by the DNS query at the time of the first name resolution in addition to the normal process of acquiring the connection destination IP address based on the connection destination host name. At that time, the communication interfaces 108 and 109 selected as communication paths are associated with each other, and in the subsequent name resolution, a format similar to a normal IP address is used as an identifier for uniquely identifying the association. A function of returning the dummy address to the application program 101 is provided.

  The host name / communication interface conversion table 104 is a storage unit that stores the connection destination host name and the communication interfaces 108 and 109 serving as communication paths in association with each other. The communication interface 108 is based on the connection destination host name or the domain name. , 109 is referred to. Based on the host name / communication interface conversion table 104, the mobile communication terminal 1 can determine the communication interface 108 or 109 used for packet transmission from the connection destination host name passed in the name resolution. An example of the host name / communication interface conversion table 104 is shown in FIG.

  The interface determination unit 105 is a unit that determines a real address and a communication path of a connection destination based on a dummy address given from an application program when a connection request to a service or transmission data is transmitted. The interface 108 or 109 is selected.

  The dummy address / communication interface correspondence database 106 is a means for storing a combination of the real address of the connection destination obtained by the DNS query at the time of name resolution and the communication interface 108 or 109 in association with the dummy address. The interface determining means 105 can determine the communication interface 108 or 109 to be used with the real address of the connection destination by referring to the dummy address / communication interface correspondence database 106 based on the dummy address given from the application program. . An example of the dummy address / communication interface correspondence database 106 is shown in FIG.

  That is, the means for determining a communication path for transmitting a packet based on a dummy address at the time of packet transmission specifically comprises an interface determining means 105 and a dummy address / communication interface correspondence database 106.

  The routing table 107 is a known means for determining the communication interface 108 or 109 to be a communication path to be used from the connection destination host name. As in the prior art, the connection destination address and the communication interface 108 or 109 associations are performed.

  The communication interface 108 is a communication interface for transmitting packets using a communication path such as a wireless LAN, and the communication interface 109 is a communication interface for transmitting packets using a communication path such as a cellular phone network. It is.

  The DNS query means 110 is a well-known means for inquiring a connection destination address using a DNS server on the network.

  The interface / DNS server correspondence table 111 is a storage unit that stores a communication path and a DNS server address to be used in a pair, and associates the communication interface 108 or 109 with the DNS server address, and performs a DNS query unit 110. Refers to this interface / DNS server correspondence table 111 and sends a DNS query to a DNS server on the network. An example of the interface / DNS server correspondence table 111 is shown in FIG.

  Next, the overall operation of the present embodiment will be described in detail with reference to FIGS. 1, 2, 3, 4, 5, 6, and 7.

  Before describing the operation, an example of a network will be described first with reference to FIG.

  Here, as an example, two networks, a wireless LAN spot 201 where a service is deployed by a wireless LAN, and a cellular phone network 202 where a service for cellular phones such as WCDMA is deployed are shown.

  An access point 203 is installed in the wireless LAN spot 201 and is connected via the communication path 205 from the mobile communication terminal 1 that uses the service. A mobile phone base station 204 is installed in the mobile phone network 202 and is connected from the mobile communication terminal 1 via the communication path 206.

  In the wireless LAN spot 201, an http server 207 for WEB service and a DNS server 208 for DNS service are deployed. In the mobile phone network 202, an http server 209 for WEB service and a DNS server 210 for DNS service are deployed. Has been.

  When the application program 101 is requested to use a service by a user operation or the like, the application program 101 connects to and communicates with a service on the network. In the present embodiment, as an example, a procedure when the mobile communication terminal 1 communicates with the http server 207 connected to the wireless LAN spot 201 will be described. The same procedure is used when communication is performed using another communication path such as a service on the cellular phone network 202.

  When the application program 101 communicates with the http server 207, it is necessary to resolve the address from the name of the http server 207. Here, a case where an IP address is resolved from a connection destination host name (for example, www.example.com) will be described as an example (FIG. 6).

  The application program 101 receives www.example.com as an input, calls an API (for example, gethostbyname ()) constituting the name resolution unit 103, and requests address resolution (step a 1).

  The name resolution means 103 searches the host name / communication interface conversion table 104 using www.example.com given as an input as a key. When the contents of the host name / communication interface conversion table 104 are as shown in FIG. 3, the host name / communication interface conversion table 104 returns the communication interface 108 to the name resolution means 103 as a search result (step a2). As a result, a communication interface serving as a communication path to be used is specified.

  The name resolution unit 103 calls the DNS query unit 110 with the communication interface 108 and the host name www.example.com as inputs. The DNS query unit 110 searches the interface / DNS server correspondence table 111 using the name of the communication interface 108 which is the determined communication path as a key. When the contents of the interface / DNS server correspondence table 111 are as shown in FIG. 5, the interface / DNS server correspondence table 111 is stored in the wireless LAN spot 201 in correspondence with the communication interface 108 which is the communication path determined in step a2. An IP address 192.168.1.1 of a certain DNS server 208 is returned to the DNS query means 110 as a DNS server used for address inquiry. The DNS query unit 110 performs a DNS query of www.example.com to the DNS server 192.168.1.1 using the determined communication interface 108, and obtains the IP address 192.168.1.20 of the http server 207 from the DNS server 208. (Hereinafter, this address is called a real address to distinguish it from a dummy address) (step a3).

  Next, the name resolution means 103 determines one arbitrary address that is not registered in the dummy address / communication interface correspondence database 106 from the address space of class E (240.0.0.0 to 255.255.255.255), and uses this as a dummy. Address (step a4).

  This dummy address is used as an “identifier” corresponding to the set of the communication interface obtained in step a2 and the real IP address obtained in step a3.

  Using the dummy address as a key, the name resolution means 103 registers the communication interface 108 obtained in step a2 and the real address 192.168.1.20 given in step a3 in the dummy address / communication interface correspondence database 106 ( Step a5).

  Next, the name resolution unit 103 returns the dummy address obtained in step a4, for example, 240.0.0.1 to the application program 101 as a result of name resolution (step a6).

  On the other hand, the application program 101 calls the transmission processing unit 102 with the dummy address 240.0.0.1 as an input when connecting to the service (step b1 in FIG. 7).

  The transmission processing unit 102 searches the dummy address / communication interface correspondence database 106 using the dummy address 240.0.0.1 given as an input as a key (step b2).

  When the contents of the dummy address / communication interface correspondence database 106 are as shown in FIG. 4, the dummy address / communication interface correspondence database 106 returns 192.168.1.20 and the communication interface 108 to the transmission processing unit 102 (step b3).

  Then, the transmission processing unit 102 issues a connection request to the interface determination unit 105 using the real address 192.168.1.20 and the communication interface 108 as arguments, and the interface determination unit 105 sets the connection destination IP address to 192.168.1.20 as a communication interface. An instruction is sent to 108 to transmit a connection packet (step b5).

  When the IP address given in step b1 is not registered in the dummy address / communication interface correspondence database 106, that is, when the real address is given from the application program 101, the transmission processing unit 102 Similarly, the communication interface is determined by searching the routing table 107 (step b4).

  As described above, by storing the relationship between the service and the communication path in the mobile communication terminal 1, the communication path is automatically selected by selecting the communication path according to the service use request from the plurality of communication paths. As a result, the user's operation when connecting the mobile communication terminal 1 to the network is reduced. As a result, the convenience of the mobile communication terminal 1 is improved.

  Next, a configuration example in the case where an optimum interface searching unit, which is a unit for determining connection reachability and communication performance at the time of data transmission, is provided will be described with reference to FIG.

  In FIG. 8, the name resolution means 103, host name / communication interface conversion table 104, dummy address / communication interface correspondence database 106, routing table 107, DNS query means 110, and interface / DNS server correspondence table 111 already described are omitted. Only the transmission processing unit 102, the interface determining unit 105, the optimum interface searching unit 112, and the communication interfaces 108 and 109 that are directly related to the determination of the reachability to the connection destination and the communication performance are shown.

  The optimum interface searching means 112 is for searching for an interface with good response performance when a data transmission request from the application program 101 is generated.

  In this embodiment, the socket information passed to the transmission processing unit 102 when the application program 101 opens a data transmission connection includes the same source IP address, source port number, destination IP address, destination In addition to the data field for storing the port number, a data field for designating a communication interface serving as a communication path is added (see FIG. 9).

  Next, the overall operation will be described in detail with reference to FIGS.

  When requested to use a service by a user operation or the like, the application program 101 performs connection and communication with a service on the network. In the present embodiment, as an example, a procedure when the mobile communication terminal 1 communicates with the http server 207 connected to the wireless LAN spot 201 will be described. The same procedure is used when communication is performed using another communication path such as a service on the cellular phone network 202.

  The application program 101 calls the transmission processing unit 102 with a socket constituting connection information as an input, and requests data transmission. Assume that the socket specified here has already been set in advance (for example, address 192.168.1.20 and port number) (step c1).

  The transmission processing unit 102 determines whether or not there is any description in the data field for designating the communication interface in this socket (step c2), and if there is no description, calls the optimum interface searching means 112. The process proceeds to step c3, and if the designation of the communication interface is described, the process proceeds to step c7 in order to start data transmission using this communication interface.

  If there is no description in the data field for designating the communication interface in the socket and the determination result in step c2 is false, the optimum interface searching means 112 determines that all the available communication interfaces (interfaces 108 and 109). Send a connection request using. The connection request in this case is a SYN packet (request signal for confirming port opening) addressed to the transmission destination address. After sending the connection request, the optimum interface searching unit 112 waits for an ACK packet (transmission permission signal) response from the connection destination (step c3).

  Then, the optimum interface searching unit 112 receives an ACK packet from any communication interface (step c4). The communication interface that receives the ACK packet first is the optimal communication interface.

  Also, the connection request is interrupted for communication interfaces other than the communication interface that first received the ACK packet. Specifically, the connection is forcibly interrupted by transmitting a FIN packet (connection end signal) to a communication interface other than the communication interface that first receives ACK (step c5).

  As described above, since the communication interface that first receives the ACK packet is the communication interface that is optimal in connection reachability and communication performance, the optimum interface searching unit 112 designates an identifier representing this communication interface as the communication interface of the socket. This is described in the data field (see FIG. 9) (step c6).

  The interface determination unit 105 starts data transmission using the communication interface described in the socket (step c7).

  The case where the TCP protocol is used has been described above. However, when the UDP protocol is used instead of the TCP protocol, the processing shown in FIG. 11 is applied.

  Since the processing of step d1, step d2, and step d6 is the same as the processing of step c1, step c2, and step c7 described above, only the processing of step d3 to step d5 that differs depending on the protocol to be used is specifically described. explain.

  In the embodiment shown in FIG. 11, when there is no description in the data field for designating the communication interface in the socket and the determination result in step d2 is false, the optimum interface searching means 112 has all the available interfaces. A connection request is issued using the communication interfaces (interfaces 108 and 109). However, the connection request in this case is a ping signal addressed to the transmission destination address (request signal for confirming the presence / absence of the node). After sending the connection request, the optimum interface searching unit 112 waits for a response of the ping signal from the connection destination (step d3).

  Then, the optimum interface searching unit 112 receives a ping signal from any communication interface (step d4). Since the communication interface that has received the ping signal is the optimal communication interface in connection reachability and communication performance, the optimum interface searching means 112 uses the identifier of this communication interface as a data field for designating the communication interface of the socket (see FIG. 9). (Step d5).

  As described above, since a communication path with good connection reachability and communication performance can be checked before the communication is executed, it is possible to select the most efficient communication interface and start communication.

  The mobile communication terminal, the communication path selection method, and the communication path selection program according to the present invention can be applied to a mobile communication terminal having a plurality of communication interfaces (communication paths).

It is the functional block diagram which showed the internal structure of the mobile communication terminal of one Embodiment to which this invention is applied. It is the conceptual diagram shown about the example of the network which the portable communication terminal of the embodiment connects. It is the conceptual diagram which showed an example of the host name and communication interface conversion table used in the embodiment. It is the conceptual diagram which showed an example of the database corresponding to a dummy address and communication interface used in the embodiment. 3 is a conceptual diagram showing an example of an interface / DNS server correspondence table used in the embodiment. FIG. It is the flowchart shown about the outline | summary of the process at the time of an application performing name resolution. It is the flowchart shown about the outline of the process at the time of an application performing a transmission process. It is the functional block diagram which showed the internal structure of the portable communication terminal which provided the optimal interface search means. It is the conceptual diagram shown above the socket which an application program passes to a transmission process part in the case of transmission of data. It is the flowchart shown about the outline of the processing operation of the optimal interface search means corresponding to TCP. It is the flowchart shown about the outline of the processing operation of the optimal interface search means corresponding to UDP.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile communication terminal 101 Application program 102 Transmission processing part 103 Name resolution means 104 Host name / communication interface conversion table 105 Interface determination means 106 Dummy address / communication interface correspondence database 107 Routing table 108, 109 Communication interface (communication route)
110 DNS query means 111 Interface / DNS server correspondence table 112 Optimal interface search means 201 Wireless LAN spot 202 Mobile phone network 203 Access point 204 Mobile phone base station 205, 206 Communication path 207 http server 208 DNS server 209 http server 210 DNS server

Claims (19)

A mobile communication terminal that can use multiple types of communication paths,
A function that returns a dummy address having the same format as an address that associates a pair of a connection destination host name and a communication path with a connection destination host name as an input, and a function that acquires a connection destination address based on the connection destination host name; A name resolution means with
A portable communication terminal comprising means for determining a communication path for transmitting a packet from the dummy address during packet transmission.   2. The mobile communication terminal according to claim 1, further comprising storage means for storing the connection destination host name and communication path in association with each other, and means for determining a communication path to be used from the connection destination host name.   The portable communication terminal according to claim 1 or 2, wherein the communication path is determined by an application designating a dummy address of a connection destination host.   Storage means that stores the real address obtained by DNS query at the time of name resolution and the communication path obtained from the connection destination host name in association with the dummy address, and determines the real address and communication path from the dummy address given at the time of connection 4. The portable communication terminal according to claim 1, further comprising means for performing the operation.   3. A storage means for storing a pair of a communication path and a DNS server address to be used, and a means for determining a DNS server address to be used from the determined communication path. Or the portable communication terminal of Claim 3.   4. The portable communication terminal according to claim 1, further comprising means for determining a reachable communication path by determining connection reachability to a connection destination when a data transmission request is made.   4. The portable communication terminal according to claim 1, further comprising means for determining a communication path having good communication performance by measuring communication performance to a connection destination when a data transmission request is made.   A communication path selection method, wherein a connection destination host name and a communication path are associated with each other and stored in a mobile communication terminal, and a communication path to be used is determined based on the connection destination host name.   The communication path selection method according to claim 8, wherein the communication path is determined by an application designating a dummy address of a connection destination host.   The real address obtained by the DNS query at the time of name resolution and the communication route obtained from the connected host name are stored in correspondence with the dummy address, and the real address and the communication route are determined from the dummy address given at the time of connection. The communication path selection method according to claim 8 or 9, wherein the communication path is selected.   11. The communication path selection method according to claim 8, wherein a communication path and a DNS server to be used are stored in pairs, and a DNS server to be used is determined from the determined communication path. .   The communication path selection method according to claim 8, 9, or 10, wherein a reachable communication path is determined by determining connection reachability to a connection destination when a data transmission request is made.   11. The communication path selection method according to claim 8, wherein a communication path with good communication performance is determined by measuring communication performance to a connection destination at the time of data transmission request.   A communication path selection characterized by causing a microprocessor of a mobile communication terminal to execute a process of storing a connection destination host name and a communication path in association with each other and a process of determining a communication path to be used based on the connection destination host name program.   15. The communication path selection program according to claim 14, wherein a communication path to be used is determined by a connection destination host name given from application software.   Processing to store the real address obtained from the DNS query at the time of name resolution and the communication path obtained from the connection destination host name in association with the dummy address, and determine the real address and the communication path from the dummy address given at the time of connection 16. The communication path selection program according to claim 14 or 15, wherein the process is executed.   16. The process of storing a communication path and a DNS server to be used in pairs and the process of determining a DNS server to be used from the determined communication path are executed. The communication route selection program described.   17. The communication path selection according to claim 14, 15 or 16, wherein a process for determining a reachable communication path by executing a connection reachability to a connection destination at the time of a data transmission request is executed. program.   17. The communication path selection according to claim 14, 15 or 16, wherein a process for determining a communication path having a good communication performance is executed by measuring a communication performance to a connection destination when a data transmission request is made. program.

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