JP5207320B2 - Communication path control device, communication path control method, and communication path control program - Google Patents

Description

  Some embodiments according to the present invention relate to a technique for controlling a communication path of a communication packet.

  Conventionally, in communication control when a plurality of communication paths exist with a communication partner, a communication confirmation packet such as ping is transmitted for each communication path to monitor the state of the communication path, and according to the presence or absence of a ping response A communication path that allows communication was selected. An example of monitoring a communication path using such a ping packet is described in Patent Document 1.

JP 2005-33658 A

  However, in the method described in Patent Document 1, it is necessary to transmit a communication confirmation packet regardless of whether communication is disabled or a communication failure occurs. ) Has occurred. Also, communication devices existing in the middle of a communication path are often set to discard packets for communication confirmation by ping or the like from the viewpoint of ensuring security. In this case, even if the communication path is actually communicable, it may be determined that communication is impossible and the communication path may not be set (established), and the accuracy of setting the communication path is low.

  Some aspects of the present invention have been made in view of the above problems, and provide a communication path control device, a communication path control method, and a communication path control program capable of setting a communication path with high accuracy. Is one of the purposes.

A communication path control device according to the present invention is a communication path control device that controls a communication path of a communication packet, and a communication monitoring unit that determines whether or not the communication packet can be communicated via one network interface; When the communication monitoring unit determines that communication is impossible , a communication confirmation packet is created based on a copy of the communication packet in the communication packet recording unit, and the communication confirmation packet is sent to the destination of the communication packet as described above . a communication confirmation unit for transmitting via the network interface, when the communication path through the other network interface described above is judged to be communication, setting the other network interface described above with the communication path of the aforementioned communication packet and a communication path setting unit, the communication monitoring unit, receiving the response information to the communication confirmation packet When determines that can communicate the communication path through the other network interface described above.

A communication path control method according to the present invention is a communication path control method for controlling a communication path of a communication packet, the communication monitoring step for determining whether or not the communication packet can be communicated via one network interface; When the communication monitoring step determines that communication is impossible , a communication confirmation packet is created based on a copy of the communication packet in the communication packet recording unit, and the communication confirmation packet is sent to the destination of the communication packet as described above . a communication confirmation step of transmitting via the network interface, when the communication path through the other network interface described above is judged to be communication, setting the other network interface described above with the communication path of the aforementioned communication packet and a communication path setting step, response to the communication confirmation packet Upon receiving the information, it determines that can communicate the communication path through the other network interface described above.

A communication path control program according to the present invention is a communication path control program for controlling a communication path of a communication packet, and includes a communication monitoring step for determining whether or not the communication packet can be communicated through one network interface; When the communication monitoring step determines that communication is impossible , a communication confirmation packet is created based on a copy of the communication packet in the communication packet recording unit, and the communication confirmation packet is sent to the destination of the communication packet as described above . a communication confirmation step of transmitting via the network interface, when the communication path through the other network interface described above is judged to be communication, setting the other network interface described above with the communication path of the aforementioned communication packet and a communication path setting step, the communication confirmation packet Upon receiving the response information in response to judges that can communicate the communication path through the other network interface described above.

  According to the present invention, when a communication packet cannot be communicated via one network interface (when communication is impossible), another network interface can be set as a communication path of the communication packet with high accuracy.

It is a block diagram explaining the network in one Embodiment of this invention. It is a block diagram explaining an example of the routing table shown in FIG. It is a flowchart explaining the operation | movement when transmitting a communication packet. It is a flowchart explaining the communication confirmation packet transmission process shown in FIG. It is a block diagram explaining an example of the packet for communication confirmation. It is a flowchart explaining the operation | movement when a packet is received.

  Embodiments of the present invention will be described below. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic. Therefore, specific dimensions and the like should be determined in light of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings. In the following description, the upper side of the drawing is referred to as “upper”, the lower side as “lower”, the left side as “left”, and the right side as “right”.

  1 to 6 show an example of the present invention. FIG. 1 is a block diagram illustrating a network according to an embodiment of the present invention. As illustrated in FIG. 1, the terminal 10 includes network interfaces 21 and 22, a communication path control unit 30, and an application program 40 that is executed by a CPU (labor saving in the figure). The communication path control unit 30 in the present embodiment corresponds to an example of a communication path control apparatus according to the present invention.

  The network interfaces 21 and 22 are respectively connected to the router R1 or the router R2 installed outside the terminal 10, and are connected to the network N1 or the network N2 via (route) the router R1 or the router R2. Or it is for each communicating with a terminal (illustration omitted). In FIG. 1, the terminal 10 includes the two network interfaces 21 and 22. However, the present invention is not limited to this, and the terminal 10 may include three or more network interfaces.

  In the following description, packet communication using IP (Internet Protocol) will be described unless otherwise specified. The communication path control unit 30 is for controlling a communication path of an IP packet (hereinafter simply referred to as a packet). The communication path control unit 30 includes a routing table 31 stored in a storage unit such as a memory, a communication packet storage unit 32, a communication monitoring unit 33, a communication confirmation unit 34, and a communication path setting unit 35.

  FIG. 2 is a configuration diagram illustrating an example of the routing table illustrated in FIG. The routing table 31 is used for storing (registering) information about a communication path in order to determine which communication path is used to transmit a packet destined for a predetermined IP address (hereinafter simply referred to as an address). It is. Each entry (each row or each record) in the routing table 31 is registered in advance by, for example, an administrator. The routing table 31 is read by the application program 40 and the communication confirmation unit 34 and written by the communication path setting unit 35. As shown in FIG. 2, the routing table 31 includes an address field 311 and a communication path field 312.

  The address column 311 stores information related to the destination address of the packet, for example, the destination address itself. As shown in FIG. 2, for example, “AD1” and “AD2” are stored in the address field 311. The communication path column 312 stores information related to the network interface corresponding to the destination address stored in the address column 311, for example, an information ID that can uniquely identify the network interfaces 21 and 22.

  In the present embodiment, as shown in FIG. 2, “IF1” in the communication path column 312 is entered for the entry whose address column 311 is “AD1”, and “IF1” is entered in the communication path column 312 for the entry whose address column 311 is “AD2”. As shown in FIG. 1, the network interface 21 is assigned “IF1” as an ID, and the network interface 21 is assigned “IF2” as an ID. Note that the routing table 31 in the present embodiment corresponds to an example of a “communication path storage unit” of the communication path control apparatus according to the present invention.

  The communication packet storage unit 32 is for storing information related to a packet (hereinafter referred to as a communication packet) transmitted in response to a request from the application program 40. In the present embodiment, the communication packet storage unit 32 stores a copy (duplication) of a communication packet as information regarding the communication packet. In the communication packet storage unit 32, the copy is read or written by the monitoring unit 33. Since the copy need only be stored for a certain period of time, the communication packet storage unit 32 may be configured to temporarily store, for example, a buffer memory.

  The communication monitoring unit 33 is for determining whether or not communication is possible by monitoring packet communication via the network interfaces 21 and 22, that is, transmission and reception. A communication packet transmitted in response to a request from the application program 40 and a packet received via the network interfaces 21 and 22 are input to the communication monitoring unit 33, and a control signal and predetermined data are transmitted to the communication confirmation unit 34 and a communication path setting unit. And 35.

  The communication confirmation unit 34 creates a communication confirmation packet A, which will be described later, and transmits the communication confirmation packet A via the network interfaces 21 and 22. Whether the communication path that has transmitted the communication confirmation packet A is communicable It is for confirmation. A packet is input to the communication confirmation unit 34 together with a control signal from the communication monitoring unit 33, and the communication confirmation unit 34 creates a communication confirmation packet A based on the input packet. Further, the communication confirmation unit 34 outputs the created communication confirmation packet A to the network interface 21 or the network interface 22.

  The communication path setting unit 35 is for setting a communication path through which communication packets can be communicated. The communication confirmation unit 34 receives the packet and the ID of the network interfaces 21 and 22 together with the control signal from the communication monitoring unit 33, and sets the communication path based on the input packet and the IDs of the network interfaces 21 and 22.

  Next, the operation of the communication path control unit 30 will be described with reference to FIGS. 3 to 6.

  FIG. 3 is a flowchart for explaining the operation when a communication packet is transmitted. When a communication packet is transmitted in response to a request from the application program 40 (S101), the communication monitoring unit 33 to which the communication packet is input from the application program 40 reads a copy of the communication packet stored in the communication packet storage unit 32, It is determined whether or not the input communication packet is the same as the copy stored in the communication packet storage unit 32 (S102). The determination criterion of “same” may be determined to be the same when a part of communication packets, for example, header portions are compared with each other and are the same, or may be determined to be the same when all are the same. Good.

  If the result of determination in S102 is not the same as the copy stored in the communication packet storage unit 32, the communication monitoring unit 33 creates a copy of the input communication packet (S103), and the copy is stored in the communication packet storage unit 32. Write and store (S104).

  On the other hand, if the result of the determination in S102 is the same as the copy stored in the communication packet storage unit 32, the input communication packet has been previously copied by the processing of S103 and S104 described above, and the communication packet storage unit It is considered that the communication packet stored in 32 is retransmitted. Therefore, the communication monitoring unit 33 detects retransmission of the communication packet (S105). Thereby, the communication monitoring unit 33 can determine whether or not communication is possible based on retransmission of the communication packet.

  Next, the communication monitoring unit 33 determines that the communication packet cannot be communicated (communication is impossible) over the communication path via the network interface registered in the routing table 31 (S106). As a result, when the application program 40 transmits the same communication packet again without receiving response information (normal response) or error information (abnormal response) for the communication packet for a predetermined time or more, the communication monitoring unit 33 determines that communication is impossible. The communication confirmation unit 34 and the communication path setting unit 35 can set a new communication path capable of communicating communication packets.

  Next, the communication monitoring unit 33 outputs the communication packet input from the application program 40 together with the control signal to the communication confirmation unit 34, and the communication confirmation unit 34 executes a communication confirmation packet transmission process S200 described later.

  FIG. 4 is a flowchart for explaining the communication confirmation packet transmission process shown in FIG. When a communication packet is input from the communication monitoring unit 33, the communication confirmation unit 34 creates a communication confirmation packet A based on the input communication packet (S201).

  FIG. 5 is a configuration diagram illustrating an example of a communication confirmation packet. As shown in FIG. 5, the communication confirmation packet A includes a header part A1 and a data part A2. The header part A1 includes a source address, a destination (destination) address, etc., and the communication confirmation part 34 copies the header part of the input communication packet and modifies a part as it is or as necessary. Then, the data is stored in the header part A1, and predetermined data is stored in the data part A2. Thereby, a communication confirmation packet A of a pseudo communication packet that is closer to the actual communication packet transmitted by the application program 40 than a packet by the conventional ping is created.

  The header part A1 includes at least the destination address of the input communication packet. As a result, it is possible to confirm whether communication is possible with the same destination as the communication packet. The predetermined data stored in the data part A2 is preferably data different from the data in the data part of the input communication packet. Thereby, the data part of a communication packet can be concealed to a communication device, for example, a router, that passes (relays) for communication confirmation.

  Next, as shown in FIG. 4, the communication confirmation unit 34 searches the address column 311 of the routing table 31 by using the destination address of the input communication packet, that is, the destination address of the communication confirmation packet A as a key. The communication path column 312 corresponding to the destination address is read, and a network interface having an ID different from the read network interface ID is selected (S202). Next, the communication confirmation unit 34 outputs the communication confirmation packet A created in the process of S201 to the network interface selected in the process of S202, and transmits the communication confirmation packet A via the network interface (S202). . For example, when the destination address of the communication confirmation packet A is “AD1”, the network interface 21 (IF1) corresponds when the routing table 31 shown in FIG. 2 is searched. Therefore, the communication confirmation unit 34 uses the network interface 21 (IF1). The communication confirmation packet A is transmitted via a network interface 22 (IF2) different from the above.

  When there are three or more N (N ≧ 3) network interfaces, for example, the communication confirmation unit 34 stores the ID of the network interface selected in the process of S202 in the buffer memory, and again for communication confirmation. When transmitting the packet A, in the process of S202, the communication confirmation unit 34 has a network interface ID that is different from the network interface ID read from the routing table 31 and the network interface ID stored in the buffer memory. May be selected. In this case, IDs of up to (N−2) network interfaces are stored in the buffer memory.

  FIG. 6 is a flowchart for explaining the operation when receiving a packet. When a packet is received via the network interface 21 or the network interface 22 (S301), the communication monitoring unit 33 to which the packet is input determines whether the received packet is an error packet related to the communication packet (S302). The determination criterion of “error packet” is determined to be an error packet when, for example, the received packet includes various types of defined error information such as including ICMP (Internet Control Message Protocol) UNREACH.

  The error packet related to the communication packet includes an error packet for the communication packet and an error packet for the communication confirmation packet A created based on the communication packet.

  If the received packet is an error packet related to the communication packet as a result of the determination in S302, the communication monitoring unit 33 determines that the communication packet cannot be communicated (communication impossible) on the communication path via the network interface that has received the packet ( S303). Thereby, when not receiving response information (normal response) but error information (abnormal response) for the communication packet or communication confirmation packet A, the communication monitoring unit 33 can determine that communication is impossible, The confirmation unit 34 and the communication path setting unit 35 can set a new communication path through which communication packets can be communicated.

  Next, the communication monitoring unit 33 outputs the error packet input together with the control signal to the communication confirmation unit 34, and the communication confirmation unit 34 executes the communication confirmation packet transmission process S200 shown in FIG. 4 as described above. . Note that the communication confirmation unit 34 creates the communication confirmation packet A based on the input error packet instead of the communication packet in the process of S201.

  On the other hand, if the received packet is not an error packet as a result of the determination in S302, the communication monitoring unit 33 determines whether the received packet is response information (normal response) for the communication confirmation packet A (S304). For example, when the received packet is a response information for the communication confirmation packet A, the response information is determined to be response information when the packet is an ACK packet (ACKnowledge) for the communication confirmation packet A.

  As a result of the determination in S304, when the received packet is response information for the communication confirmation packet A, the communication packet including the destination address of the communication confirmation packet A is communicated through the communication path via the network interface selected in the process of S202. It is thought that it can (communication is possible). In the above example, it is considered that a communication packet including the destination address “AD1” of the communication confirmation packet A can be communicated via the network interface 22 (IF2). Therefore, the communication monitoring unit 33 determines that the communication path can be set (S305). Thus, when the response information for the communication confirmation packet A is received, the network interface that has transmitted the communication confirmation packet A can be set as a communication path.

  Next, the communication monitoring unit 33 outputs the packet received together with the control signal and the ID of the network interface that has received the packet to the communication path setting unit 35. The communication path setting unit 35 registers the source address of the input packet, that is, the destination address of the communication packet and the network interface ID in the routing table 31 (S306). As a result, a new network interface can be set as a communication path through which communication packets can be communicated.

  On the other hand, if the received packet is not a response to the communication confirmation packet A as a result of the determination in S304, the received packet is neither an error packet related to the communication packet nor response information (normal response) to the communication confirmation packet A. This is considered response information (normal response) to the communication packet. Therefore, the communication monitoring unit 33 determines that the response is a response to the communication packet (S307), and ends the process without doing anything.

  In the present embodiment, the communication path control unit 30 is built in the terminal 10, but the present invention is not limited to this. For example, the communication path control unit 30 is separate from the terminal 10 as a communication path control device. Also good.

  As described above, according to the communication path control unit 30 in the present embodiment, the communication monitoring unit 33 determines whether communication packets can be communicated via the network interface registered in the routing table 31. Thus, instead of receiving information on whether communication is possible (not passive), it is possible to determine whether communication is possible for the communication path via the network interface registered in the routing table 31 (active). ). Further, when receiving response information for the communication confirmation packet A, the communication path setting unit 34 sets the network interface that has transmitted the communication confirmation packet A as a communication path. Thus, when a communication packet cannot be communicated on a communication path via one network interface (when communication is not possible), another network interface can be set as a communication path of the communication packet with high accuracy. Furthermore, when the communication monitoring unit 33 determines that communication is not possible, the communication confirmation unit 34 creates and transmits the communication confirmation packet A, so it is necessary to periodically transmit the communication confirmation packet as in the past. Absent.

  In addition, according to the communication path control unit 30 in the present embodiment, the communication management unit 33 cannot communicate a communication packet with respect to the communication path via the network interface registered in the routing table 31 when detecting the retransmission of the communication packet. Is determined. As a result, when the application program 40 transmits the same communication packet again without receiving response information (normal response) or error information (abnormal response) for the communication packet for a predetermined time or more, the communication monitoring unit 33 determines that communication is impossible. The communication confirmation unit 34 and the communication path setting unit 35 can set a new communication path capable of communicating communication packets.

  In particular, when transmitting a communication packet, the communication monitoring unit 33 detects retransmission of the communication packet based on the communication packet and a copy stored in the communication packet storage unit 32. Thereby, the communication monitoring unit 33 can determine whether or not communication is possible for the communication path via the network interface registered in the routing table 31 based on the retransmission of the communication packet.

  Further, according to the communication path control unit 30 in the present embodiment, when receiving the error information regarding the communication packet, the communication monitoring unit 33 determines that the communication path via the network interface that has received the error information is incapable of communication. Thereby, when not receiving response information (normal response) but error information (abnormal response) for the communication packet or communication confirmation packet A, the communication monitoring unit 33 can determine that communication is impossible, The confirmation unit 34 and the communication path setting unit 35 can set a new communication path through which communication packets can be communicated.

  Further, according to the communication path control unit 30 in the present embodiment, the communication confirmation unit 34 stores data different from the data part of the communication packet in the data part A2. Thereby, the data part of a communication packet can be concealed to a communication device, for example, a router, that passes (relays) for communication confirmation. Further, it is possible to create a communication confirmation packet A of a pseudo communication packet that is closer to an actual communication packet transmitted by the application program 40 than a packet by a conventional ping, and a communication path compared to a packet by a conventional ping In a communication device or the like existing in the middle of the communication, the possibility that the communication confirmation packet A is discarded becomes low, and it is possible to confirm whether communication is possible with high accuracy.

  Further, according to the communication path control unit 30 in the present embodiment, the communication path setting unit 35 stores information regarding the destination address of the communication packet as information regarding the communication path and information regarding the network interface corresponding to the destination address. 31 is registered and stored. As a result, a new network interface can be set as a communication path through which communication packets can be communicated.

  Note that the configurations of the above-described embodiments may be combined or a part of the components may be replaced. The configuration of the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the scope of the present invention.

  Part or all of the above-described embodiments can be described as in the following supplementary notes, but is not limited thereto.

  (Supplementary note 1) A communication path control device for controlling a communication path of a communication packet, wherein the communication monitoring section determines whether or not the communication packet can be communicated via one network interface, and communicates with the communication monitoring section. A communication confirmation unit configured to create a communication confirmation packet whose destination is the destination address of the communication packet when it is determined to be impossible, and to transmit the communication confirmation packet via another network interface; A communication path control apparatus comprising: a communication path setting unit that sets the other network interface as a communication path of the communication packet when response information for the packet is received.

(Supplementary note 2) The communication path control device according to supplementary note 1, wherein the communication monitoring unit determines that communication is impossible for a communication path via the one network interface when detecting retransmission of the communication packet. .

  (Additional remark 3) The said communication monitoring part has a communication packet memory | storage part which memorize | stores the information regarding one said communication packet, When transmitting the said other communication packet, this other communication packet and the said communication packet memory | storage part The communication path control device according to appendix 2, wherein retransmission of the one communication packet is detected based on the information stored in the information.

  (Additional remark 4) When the said communication monitoring part receives the error information regarding the said communication packet, it determines with the communication path | route via said one network interface being incommunicable. The communication path control device described.

  (Supplementary note 5) The communication path control device according to any one of supplementary notes 1 to 4, wherein the communication confirmation packet includes data different from a data part of the communication packet.

  (Additional remark 6) The said communication path setting part has a communication path memory | storage part which memorize | stores the information regarding the destination address of the said communication packet as the information regarding a communication path, and the information regarding the said network interface corresponding to this destination address, The communication path control device according to any one of appendices 1 to 5.

  (Supplementary note 7) A communication path control method for controlling a communication path of a communication packet, the communication monitoring step for determining whether or not the communication packet can be communicated via one network interface, and the communication monitoring step being impossible. A communication confirmation step of creating a communication confirmation packet destined to the destination address of the communication packet and transmitting the communication confirmation packet via another network interface when the communication confirmation packet is determined, and the communication confirmation packet And a communication path setting step of setting the other network interface as a communication path of the communication packet when response information to the communication packet is received.

(Appendix 8) A communication path control program for controlling a communication path of a communication packet,
A communication monitoring step for determining whether or not the communication packet can be communicated via a single network interface; and a communication confirmation destination addressed to the destination address of the communication packet when the communication monitoring step determines that communication is impossible A communication confirmation step of creating a packet and transmitting the communication confirmation packet via another network interface; and when receiving response information to the communication confirmation packet, the other network as a communication path of the communication packet A communication path control program comprising: a communication path setting step for setting an interface.

  21, 22 ... Network interface, 30 ... Communication path control unit, 31 ... Routing table, 32 ... Communication packet storage unit, 33 ... Communication monitoring unit, 34 ... Communication confirmation unit, 35 ... Communication path setting unit, A ... For communication confirmation packet

Claims (8)

A communication path control device for controlling a communication path of a communication packet,
A communication monitoring unit that determines whether or not the communication packet can be communicated via a network interface;
When the communication monitoring unit determines that communication is impossible , a communication confirmation packet is created based on a copy of the communication packet in the communication packet recording unit , and the communication confirmation packet is used as a destination of the communication packet to another network. A communication confirmation unit for transmitting via an interface;
A communication path setting unit that sets the other network interface as a communication path of the communication packet when it is determined that a communication path via the other network interface is communicable ,
The communication monitoring unit is characterized in that, when receiving response information for the communication confirmation packet, the communication monitoring unit determines that communication is possible for a communication path via the other network interface . The communication path control device according to claim 1, wherein the communication monitoring unit determines that communication is not possible for a communication path via the one network interface when detecting retransmission of the communication packet. The communication monitoring unit
A communication packet storage unit for storing information related to the one communication packet;
3. When transmitting another communication packet, retransmission of the one communication packet is detected based on the other communication packet and information stored in the communication packet storage unit. The communication path control device according to 1. The said communication monitoring part determines with the communication path | route via said one network interface being incommunicable, when the error information regarding the said communication packet is received. Communication path control device. The communication path control device according to any one of claims 1 to 4, wherein the communication confirmation packet includes data different from a data part of the communication packet. The communication path setting unit includes a communication path storage unit that stores information about a destination address of the communication packet and information about the network interface corresponding to the destination address as information about the communication path. The communication path control device according to any one of claims 1 to 5. A communication path control method for controlling a communication path of a communication packet,
A communication monitoring step for determining whether or not the communication packet can be communicated via a network interface;
When it is determined by the communication monitoring step that communication is impossible , a communication confirmation packet is created based on a copy of the communication packet in the communication packet recording unit , and the communication confirmation packet is set as the destination of the communication packet to another network interface. A communication confirmation step for transmitting via
A communication path setting step of setting the other network interface as a communication path of the communication packet when it is determined that a communication path via the other network interface is communicable ,
A communication path control method , comprising: determining that communication is possible for a communication path via the other network interface when response information for the communication confirmation packet is received . A communication path control program for controlling a communication path of a communication packet,
A communication monitoring step for determining whether or not the communication packet can be communicated via a network interface;
When it is determined by the communication monitoring step that communication is impossible , a communication confirmation packet is created based on a copy of the communication packet in the communication packet recording unit , and the communication confirmation packet is set as the destination of the communication packet to another network interface. A communication confirmation step for transmitting via
A communication path setting step of setting the other network interface as a communication path of the communication packet when it is determined that a communication path via the other network interface is communicable ,
A communication path control program for determining that communication is possible for a communication path via the other network interface when response information for the communication confirmation packet is received .

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