JP2011103623A - Communication control apparatus, communication control method and communication control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication control apparatus, communication control method and communication control program capable of preventing origination information, which is to be transmitted from a calling source to a called destination, from being transmitted/received while being looped. <P>SOLUTION: The communication control apparatus 20 includes: a history addition means 21 for adding origination history information indicating contents of origination information to the origination information when transmitting the origination information from a communication terminal device 31 of a calling source to a communication terminal device 32 of a called destination; and a comparison means 22 for comparing contents indicated by the origination information with contents indicated by the origination history information added to the origination information when the origination information is transmitted to the communication terminal device 31 of the calling source, and discarding the origination information when the compared contents are coincident. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication control device, a communication control method, and a communication control program.

  A private branch exchange that accommodates ISDN (Integrated Services Digital Network) public lines has a function to automatically transfer to a telephone having an arbitrary telephone number when an incoming call is received from an extension telephone that controls the connection. ing. However, if the extension telephone's dial-in number is set to the extension telephone's automatic transfer destination by mistake, and there is an incoming call to that extension telephone, the private branch exchange will automatically transfer the ISDN public line via the ISDN public line. The call is sent to the ISDN public network, but the call arrives again at the extension telephone that is the automatic transfer destination. Then, the private branch exchange transmits again to the ISDN public network through the ISDN public line by automatic transfer. As a result, outgoing and incoming calls are looped on the ISDN public line.

  In other words, there is a problem that outgoing information transmitted from the caller to the callee is looped and sent and received due to the call, which temporarily places a heavy load on the private branch exchange. In addition, since the ISDN public line is temporarily blocked, there is a problem that the telephone service is delayed.

  In Patent Document 1, the source station number and the trunk line number added to the call setting information are registered in the switching center through which the call setting information passes, and loop prevention is performed based on the registered information. A technique capable of supporting a large-scale network without increasing the amount of data is disclosed. However, since the technique disclosed in Patent Document 1 needs to register information in the exchange for each call setting information, for example, a large number of unspecified call setting information is transmitted, such as a public network and a public line. In a network, the amount of information that needs to be registered with an exchange is enormous, which is not realistic.

  Further, in Patent Document 2, when the transmission source of a packet received from the second network is the first network, the transfer of the packet to the first network is stopped to prevent the occurrence of an infinite loop. Techniques to do this are disclosed. However, in Patent Document 2, transmission information transmission / reception is performed in a loop by adding transmission history information indicating the content of transmission information to transmission information transmitted from a transmission source to a destination. It does not disclose a specific technique for preventing the problem.

Japanese Patent Laid-Open No. 04-253451 Japanese Patent Laid-Open No. 2008-124813

  As described in the background art, there is a problem that transmission / reception of transmission information transmitted from a transmission source to a reception destination may be performed in a loop.

  In order to solve the above-described problems, an object of the present invention is to provide a communication control device and a communication that can prevent a transmission / reception of transmission information transmitted from a transmission source to a reception destination from being performed in a loop. A control method and a communication control program are provided.

  The communication control device according to the first aspect of the present invention, when the transmission information is transmitted from the communication terminal device of the transmission source to the communication terminal device of the reception destination, the transmission history information indicating the content of the transmission information. The history adding means for adding to the transmission information, the content indicated by the transmission information when the transmission information is transmitted to the communication terminal device of the transmission source, and the transmission history information added to the transmission information are And comparing means for discarding the transmission information when the compared contents match.

  In the communication control method according to the second aspect of the present invention, when the transmission information is transmitted from the communication terminal device of the transmission source to the communication terminal device of the reception destination, the transmission history information indicating the content of the transmission information is displayed. The step of adding to the transmission information, the content indicated by the transmission information when the transmission information is transmitted to the communication terminal device of the transmission source, and the content indicated by the transmission history information added to the transmission information And a step of discarding the transmission information when the compared contents match.

  The communication control program according to the third aspect of the present invention, when the transmission information is transmitted from the communication terminal device of the transmission source to the communication terminal device of the reception destination, the transmission history information indicating the content of the transmission information. The step of adding to the transmission information, the content indicated by the transmission information when the transmission information is transmitted to the communication terminal device of the transmission source, and the content indicated by the transmission history information added to the transmission information And a step of discarding the transmission information when the compared contents coincide with each other.

  According to each aspect of the present invention described above, a communication control device, a communication control method, and a communication control program that can prevent transmission / reception of transmission information transmitted from a transmission source to a reception destination in a loop. Can be provided.

It is a figure which shows the structure of the communication control apparatus concerning Embodiment 1 of this invention, and its peripheral device. It is a figure which shows the structure of the private branch exchange and its peripheral device concerning Embodiment 2 of this invention. It is a figure which shows the information contained in the SETUP message of an ISDN protocol. It is a figure which shows an example of the user user information of the SETUP message concerning Embodiment 2 of this invention. It is a flowchart which shows the loop control process of the private branch exchange concerning Embodiment 2 of this invention.

Embodiment 1 of the present invention.
A communication control apparatus according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram illustrating the configuration of the communication control apparatus according to the first embodiment of the present invention.

  The communication control device 20 includes a history addition unit 21 and a comparison unit 22. Further, the communication control device 20 is connected to communication terminal devices 31 and 32. Here, a case where transmission is performed from the communication terminal device 31 to the communication terminal device 32 is illustrated. The communication terminal device 31 and the communication terminal device 32 may be the same communication terminal device.

The history adding means 21 adds the transmission history information indicating the content of the transmission information to the transmission information when the transmission information is transmitted from the communication terminal device 31 of the transmission source to the communication terminal device 32 of the reception destination.
The comparison unit 22 compares and compares the content indicated by the transmission information with the content indicated by the transmission history information added to the transmission information when the transmission information is transmitted to the communication terminal device 31 that is the transmission source. If the contents match, the outgoing information is discarded.

Subsequently, processing of the communication control apparatus according to the first embodiment of the present invention will be described.
When transmission is made from the communication terminal device 31 to the communication terminal device 32, transmission information is transmitted from the communication terminal device 31 to the communication terminal device 32.
When the transmission information is transmitted from the communication terminal device 31 to the communication terminal device 32, the history addition means 21 adds the transmission history information indicating the content of the transmission information to the transmission information.
The comparison unit 22 adds the content indicated by the transmission information and the transmission information when the transmission information transmitted from the communication terminal device 31 to the communication terminal device 32 is transmitted to the communication terminal device 31. The content indicated by the transmission history information is compared. If the compared content matches, the transmission information is discarded.

Embodiment 2 of the present invention.
With reference to FIG. 2, the configuration of the private branch exchange and the peripheral devices according to the second embodiment of the present invention will be described. FIG. 2 is a diagram showing the configuration of the private branch exchange and the peripheral devices according to the second embodiment of the present invention.

  The private branch exchange 1 includes a SW (switch) control module 2, a CPU (Central Processing Unit) 3, and a memory 4. The private branch exchange 1 is connected to an extension telephone 5. The private branch exchange 1 is connected to the ISDN public network 8 through the trunk 6 through the ISDN public line 7.

The private branch exchange 1 controls the connection between the extension telephone 5 and the ISDN public network 8 and the information transmitted and received between the extension telephone 5 and the ISDN public network 8. The private branch exchange 1 has a function of automatically transferring an incoming call to the extension telephone 5 to a telephone number of an arbitrary transfer destination.
The SW control module 2 controls the connection between the extension telephone 5 and the ISDN public network 8.
The CPU 3 controls the SW control module 2. The CPU 3 controls information transmitted to and received from the ISDN public network 8. For example, generation of a SETUP message to be described later, addition of outgoing call history information, determination in loop restriction processing, and the like are performed.
The memory 4 is a storage device that stores information necessary for the operation of the CPU 3. The memory 4 may be a storage device such as a hard disk or an optical disk other than the memory.

  The extension telephone 5 is a communication terminal device to which an arbitrary dial-in telephone number is assigned in advance. The communication terminal device may be a facsimile, a PC (Personal Computer), or the like other than the extension telephone. In the second embodiment, a case where “123456” is assigned as a dial-in number and “3000” is assigned as an extension number will be described as an example.

The trunk 6 is a device that functions as an interface in the ISDN public line 7.
The ISDN public line 7 is PRI (Primary Rate Interface), and a telephone line for 23 lines can be used. In the second embodiment, a case where the access code specifying the ISDN public line 7 is “0” will be described as an example. For example, when a call is made from the extension telephone 5 to the telephone number “789123” via the ISDN public line 7, the dial number is “0 + 789123”.

  Next, user / user information according to the second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a diagram showing information included in the SETUP message of the ISDN protocol defined in JT-Q931. FIG. 4 is a diagram showing an example of user / user information of the SETUP message according to the second embodiment of the present invention.

  As shown in FIG. 3, in the ISDN protocol, user / user information is defined as an area in which arbitrary information can be set in a SETUP message that is information for setting a call. User / user information is information that is transparently transferred from a caller to a callee. The SETUP message corresponds to transmission information.

  The user / user information is used to add call history information indicating the contents of the SETUP message transmitted by the private branch exchange 1 as a history. Specifically, as shown in FIG. 4, when making a call to the ISDN public line 7, the private telephone exchange 1 includes a loop restriction information identifier, a private telephone exchange identification code, a user / user information of a SETUP message to be transmitted, Call history information including caller ID information and dial number information is set. Among the user / user information shown in FIG. 4, the loop restriction information identifier, the private branch exchange identification code, the caller ID information, and the dial number information are newly defined information.

The loop restriction information identifier is information for identifying whether or not to restrict the loop.
The private branch exchange identification code is information for identifying the private branch exchange. The private branch exchange identification code is stored in advance in the memory 4 of the private branch exchange 1, for example, and can be set by referring to it.
The caller number information is set to the same telephone number set as the calling number of the SETUP message.
The dial number information is a destination telephone number. The dial number information is set including the access code when it is necessary to specify the access code of the ISDN public line 7 at the time of outgoing call. The dial number information becomes a transfer destination telephone number at the time of automatic transfer.

  Next, processing of the private branch exchange 1 according to the second exemplary embodiment of the present invention will be described with reference to FIG. FIG. 5 is a flowchart showing loop restriction processing of the private branch exchange 1 according to the second exemplary embodiment of the present invention.

  When a call is made from an external telephone to the dial-in number “123456” of the extension telephone 5 via the ISDN public network 8, the private branch exchange 1 detects an incoming call to the extension telephone 5. Specifically, the private branch exchange 1 receives a SETUP message transmitted from an external telephone. Here, in the private branch exchange 1, it is assumed that automatic transfer of incoming calls to the dial-in number “123456” of the extension telephone 5 is enabled. In addition, it is assumed that the dial-in number “0 + 123456” of the extension telephone 5 via the ISDN public line 7 is registered as the transfer destination telephone number.

  In this case, the private branch exchange 1 transfers the registered transfer destination telephone number “0 + 123456”. The private branch exchange 1 makes a call to the extension telephone 5 via the ISDN public line 7 designated by the access code “0” by automatic transfer. Specifically, since the transfer is made from the extension telephone 5 to the extension telephone 5, the private branch exchange 1 generates a SETUP message in which the calling number is set to “1234567” and the called number is set to “1234567”.

  At this time, as shown in FIG. 4, the private branch exchange 1 sets a loop restriction information identifier, a private branch exchange identification code, caller ID information, and dial number information in the user / user information of the SETUP message. Then, the private branch exchange 1 transmits a SETUP message to the ISDN public line 7. That is, a SETUP message, which is transmission information, is transmitted from the extension telephone 5 serving as a communication terminal apparatus of a transmission source to the extension telephone 5 serving as a communication terminal apparatus of a reception destination.

Here, the private branch exchange 1 sets a character string “LoopPrevention” indicating that the loop is restricted in the loop restriction information identifier. In this way, only SETUP messages that need to be restricted can be specified to restrict the loop. Note that the information is not limited to this as long as the information indicates whether or not the loop is restricted.
Further, the private branch exchange 1 sets “abiko station” as information for identifying the private branch exchange 1 in the private branch exchange identification code. That is, here, it is assumed that the memory 4 of the private branch exchange 1 stores “Abiko Station” as the private branch exchange identification code. Although the character string of the name of the exchange station where the private branch exchange 1 is installed is set, any information can be used as long as the private branch exchange 1 can be identified.

Also, the private branch exchange 1 sets the telephone number set as the calling number of the SETUP message in the caller number information.
Further, the private branch exchange 1 sets the dial-in number “01234567” of the extension telephone 5 including the access code of the ISDN public line 7 in the dial number information.

  Thereafter, since the dial-in number “1234567” of the extension telephone 5 is set as the calling number of the SETUP message, the SETUP message is transmitted to the private branch exchange 1 again via the ISDN public network 8. That is, the private branch exchange 1 again detects an incoming call to the extension telephone 5.

  At this time, the private branch exchange 1 performs a loop restriction process shown in FIG. 4 in order to prevent the SETUP message from being transmitted and received in a loop. Hereinafter, the loop restriction process shown in FIG. 4 will be described.

  Upon receipt of the SETUP message, the private branch exchange 1 determines whether user / user information is included in the received SETUP message (S10). Whether there is user / user information is determined by, for example, whether a user / user information identifier is stored as an information element identifier. Here, since the user / user information is set as described above, it is determined that there is user / user information in the SETUP message (S10: YES).

  On the other hand, if it is determined that the user / user information is not set (S10: NO), the private branch exchange 1 performs automatic transfer when automatic transfer is enabled. If automatic transfer is not enabled, incoming calls to the extension telephone 5 are permitted.

  If it is determined that there is user / user information, the private branch exchange 1 determines whether the loop restriction information identifier of the user / user information indicates that the loop is restricted (S11). Here, as described above, since “LoopPrevention” indicating that the loop is restricted is set in the loop restriction information identifier, it is determined that the loop restriction information identifier indicates that the loop is restricted (S11: YES). .

  On the other hand, when it is determined that the loop restriction information identifier does not indicate that the loop is restricted (S11: NO), the received SETUP message does not need to restrict the loop. Therefore, the private branch exchange 1 permits automatic transfer or incoming call as described above.

  If the private branch exchange 1 determines that the loop restriction information identifier indicates that the loop is restricted, the private branch exchange identification code of the user / user information and the private branch exchange identification code stored in the private branch exchange 1 are stored. A comparison is made to determine whether or not they match (S12). Here, as described above, the private telephone exchange identification code stored in the memory 4 of the private telephone exchange 1 is set in the user / user information. Therefore, the private branch exchange 1 determines that the private branch exchange identification codes match (S12: YES).

  On the other hand, when it is determined that the private branch exchange identification codes do not match (S12: NO), the user / user information added to the received SETUP message is not set by the private branch exchange 1. That is, it is not a SETUP message transmitted from the private branch exchange 1 and looped back again. Therefore, the private branch exchange 1 permits automatic transfer or incoming call as described above.

  If the private branch exchange 1 determines that the private branch exchange identification codes do not match, the contents of the calling number included in the SETUP message and the contents of the caller ID information included in the user / user information are compared and matched. It is determined whether or not (S13). Here, as described above, since “123456” is set as the calling number of the SETUP message and “123456” is set as the calling number of the user / user information, the contents match (S13: YES). .

  On the other hand, if the contents of the calling party number and the contents of the caller ID information do not match (S13: NO), the received SETUP message is not the transmitted SETUP message itself, so as described above, automatic transfer or incoming is permitted. To do.

  If the private branch exchange 1 determines that the content of the calling number and the content of the caller ID information match, it compares the content of the called number included in the SETUP message with the content of the dial number information of the user / user information. It is determined whether or not they match (S14). As described above, “123456” is set as the called number of the SETUP message, and “0123456” is set as the dial number information of the user / user information.

  Here, generally, when the automatic transfer is enabled for the incoming call to the extension telephone 5, the private branch exchange 1 has the dial-in number “123456” of the extension telephone 5 and the transfer destination telephone number “0123456”. Is stored in the memory 4, and a SETUP message is generated using the information to perform a transfer process. Further, the private branch exchange 1 stores information in which the dial-in number “123456” of the extension telephone 5 is associated with the extension number “3000” of the extension telephone 5 in the memory 4, and automatic transfer is enabled. If it is not, the incoming call for the dial-in number “123456” can be recognized as an incoming call for the extension telephone 5 with the extension number “3000”.

  The private branch exchange 1 refers to this information and expands “123456” as the called party number of the SETUP message. Specifically, as described above, since automatic transfer of incoming calls to the extension telephone 5 is enabled, the called number “123456” indicates the transfer destination telephone number “0123456” associated therewith. Recognize that Therefore, the called party number “123456” of the SETUP message indicates “0123456”, and the dial number information of the user / user information is “0123456”, so the contents match (S14: YES).

  In that case, it can be understood from the determination results in steps S11 to S14 that the same SETUP message as that transmitted once is received, and that the SETUP message transmitted by itself is returned. It can also be seen that if a SETUP message with that content is transmitted, it will return again. For this reason, the private branch exchange 1 discards the received SETUP message and does not transmit it to the transfer destination telephone number “0123456”. Thereby, it is possible to prevent the SETUP message transmitted from the private branch exchange 1 from being transmitted and received in a loop on the ISDN public line 7.

  On the other hand, if the content of the called number does not match the content of the dial number information (S14: NO), the received SETUP message is not the transmitted SETUP message itself, and thus automatic transfer or incoming is permitted as described above.

  As described above, according to the present embodiment, when the transmission information is transmitted from the communication terminal device of the transmission source to the communication terminal device of the reception destination, the transmission history information indicating the content of the transmission information is displayed. I try to add it. In addition, when the transmitted transmission information is transmitted to the communication terminal device of the transmission source, the content indicated by the transmission information is compared with the content indicated by the transmission history information added to the transmission information. When the compared contents match, the transmission information is discarded. As a result, it is possible to prevent the transmission information that returns upon transmission from being transmitted again, and to prevent transmission / reception of the transmission information from being performed in a loop.

  Further, according to the second embodiment, when comparing the content indicated by the transmission information with the content indicated by the transmission history information added to the transmission information, the communication terminal device of the transmission source included in the caller information And the telephone number of the destination communication terminal device are included in the outgoing call history information for comparison. That is, it is possible to prevent looping transmission / reception of transmission information transmitted from the same transmission source communication terminal apparatus to the same destination communication terminal apparatus. In this way, if the destination is updated by the time the outgoing information once sent back, it will not loop even if the outgoing information is sent again, without discarding the outgoing information. Be able to send.

  For example, specifically, in the second embodiment described above, the telephone number of the transfer destination in the automatic transfer is the extension telephone 5 after the private telephone exchange 1 transmits the SETUP message and receives the SETUP message again. If the telephone number is changed to a telephone number other than that which can be received, the contents of the called number do not match the contents of the dialed number in step S14. Therefore, automatic transfer is performed to the newly set telephone, and the incoming call can be made by the telephone. In addition, when a similar case other than the one exemplified here appears, the incoming call can be made similarly.

Other embodiments of the invention.
The embodiment described above can also be applied to FMC (Fixed Mobile Convergence), which is a service that can use a mobile phone as an extension. Here, in the FMC service, as described in the background art, when outgoing calls are made from an extension telephone to a mobile phone whose contract has been canceled via a private branch exchange, the outgoing information transmitted from the caller to the callee is There are cases where data is transmitted and received in a loop.

  More specifically, in the configuration shown in FIG. 1, the contracted mobile phone in the reception area of the access point connected to the ISDN public network 8 from the extension telephone 5 via the private telephone exchange 1 (see FIG. When the call is sent to the mobile phone, the ISDN public network 8 returns the call back to the caller. That is, the private branch exchange 1 receives the SETUP message transmitted to the mobile phone again. However, the private branch exchange 1 transmits the received SETUP message to the ISDN public network 8 again because the called party number of the received SETUP message indicates the telephone number of the mobile phone. As a result, in the private branch exchange 1, the SETUP message transmitted from the caller extension telephone 5 to the callee mobile phone is transmitted and received in a loop. Even in such a case, a loop can be prevented by the processing in the above-described embodiment.

  For example, when the extension telephone number of the mobile phone is “7000” and the extension telephone number of the extension telephone 5 is “3000”, the outgoing number of the SETUP message is “3000” and the incoming number of the SETUP message is “7000”. “3000” is set in the caller ID information of the call history information, and “7000” is set in the dial number information of the call history information. Therefore, in the loop regulation process, the contents of the calling number and the contents of the caller ID information are matched, and the contents of the called number and the dialed number information are matched, so that the SETUP message is discarded and a loop can be prevented. .

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. For example, the present invention may be applied to a VoIP (Voice over Internet Protocol) server system instead of a private branch exchange using an ISDN public line. That is, the present invention may be applied to a case where the SIP protocol used in VoIP is used as a protocol for performing call control in addition to the ISDN protocol. For example, adding loop history information to an INVITE message for setting a call in the SIP protocol performs a loop restriction process.

Further, the present invention may be applied to a Dp channel common line using the ISDN protocol or a dedicated line such as QSIG.
Further, the outgoing time information indicating the time of outgoing call is further set in the outgoing call history information, the time when the SETUP message is received is compared with the time indicated by the outgoing time information, and the time difference is less than the predetermined time. In some cases, the loop restriction process may not be performed, and the loop restriction process may be performed when the time difference is equal to or longer than a predetermined time.

  The communication control apparatus and private branch exchange according to the present invention described above supply a storage medium storing a program for realizing the functions of the above-described embodiments to the apparatus, and a CPU (Central Processing Unit), MPU included in the apparatus (Micro Processing Unit) can be configured by executing this program.

  In addition, this program can be stored in various types of storage media and can be transmitted via a communication medium. Here, examples of the storage medium include a flexible disk, a hard disk, a magnetic disk, a magneto-optical disk, a CD-ROM (Compact Disc Read Only Memory), a DVD (Digital Versatile Disc), and a BD (Blu-ray (registered trademark) Disc. ), ROM (Read Only Memory) cartridge, RAM (Random Access Memory) with battery backup, memory cartridge, flash memory cartridge, and nonvolatile RAM cartridge. The communication medium includes a wired communication medium such as a telephone line and a wireless communication medium such as a microwave line. Moreover, the above-mentioned program can also be transmitted via the Internet.

  In addition, by executing a program that implements the functions of the above-described embodiment, not only the functions of the above-described embodiment are realized, but also an OS ( The case where the functions of the above-described embodiment are realized in cooperation with the Operating System) or application software is also included in the embodiment of the invention.

  Further, when the functions of the above-described embodiment are realized by performing all or part of the processing of the program by a function expansion board inserted into the computer or a function expansion unit connected to the computer, the present invention may be implemented. It is included in the form.

1 Private branch exchange 2 SW control module 3 CPU
4 memory 5 extension telephone 6 trunk 7 ISDN public line 8 ISDN public network 20 communication control unit 21 history addition unit 22 comparison unit 31 and 32 communication terminal unit

Claims (10)

A history adding means for adding transmission history information indicating the content of the transmission information to the transmission information when transmission information is transmitted from the communication terminal device of the transmission source to the communication terminal device of the reception destination;
When the transmission information is transmitted to the communication terminal device of the transmission source, the content indicated by the transmission information is compared with the content indicated by the transmission history information added to the transmission information. A communication control unit comprising: a comparing unit that discards the transmission information when the two match. The transmission information includes a telephone number of the communication terminal device of the transmission source and a telephone number of the communication terminal device of the reception destination,
The communication control device according to claim 1, wherein the comparison means includes a telephone number of the caller communication terminal device and a telephone number of the callee communication terminal device. The communication control device further comprises storage means for storing device specifying information for identifying the communication control device,
The outgoing call history information includes device identification information of a communication control device to which the outgoing call history information is added,
The communication control according to claim 1 or 2, wherein the comparison unit performs the comparison when the device identification information stored in the storage unit of the own device matches the device identification information included in the transmission history information. apparatus.   The communication control device according to any one of claims 1 to 3, wherein the communication control device is included in a telephone exchange that controls connection of the communication terminal device that is the transmission source. The telephone exchange is a private branch exchange;
The communication control device according to claim 4, wherein the communication terminal device as the caller is an extension telephone.   The communication control apparatus according to claim 1, wherein the communication terminal apparatus is a communication terminal apparatus in FMC (Fixed Mobile Convergence).   The communication control device according to any one of claims 1 to 6, wherein the transmission information is information for performing call setting from the communication terminal device of the transmission source to the communication terminal device of the reception destination. The outgoing information is a SETUP message in ISDN (Integrated Services Digital Network) protocol,
The communication control apparatus according to claim 7, wherein the outgoing call history information is added as user / user information included in the SETUP message. A step of adding transmission history information indicating the content of the transmission information to the transmission information when the transmission information is transmitted from the communication terminal device of the transmission source to the communication terminal device of the reception destination;
A step of comparing the content indicated by the transmission information with the content indicated by the transmission history information added to the transmission information when the transmission information is transmitted to the communication terminal device of the transmission source;
And a step of discarding the transmission information when the compared contents match. A step of adding transmission history information indicating the content of the transmission information to the transmission information when the transmission information is transmitted from the communication terminal device of the transmission source to the communication terminal device of the reception destination;
A step of comparing the content indicated by the transmission information with the content indicated by the transmission history information added to the transmission information when the transmission information is transmitted to the communication terminal device of the transmission source;
A communication control program for causing a computer to execute the step of discarding the transmission information when the compared contents match.

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