JP4044082B2 - Selection device, conversion device, selection method, conversion method, computer program - Google Patents

Description

  The present invention relates to a selection device, a conversion device, a selection method, a conversion method, and a computer program in a server for establishing a real-time communication connection such as an IP phone.

  When real-time communication is performed via a distributed network such as the Internet, the calling terminal may not know the media processing method adopted by the called terminal. For example, in a so-called IP phone that performs voice communication using the TCP / IP protocol on the Internet, call setting and disconnection are defined by a protocol such as SIP (Session Initiation Protocol). However, a media processing method (codec method) such as an audio encoding method or a compression method is not particularly defined in SIP or the like. Therefore, there is a possibility that different media processing methods are adopted between the calling terminal and the called terminal.

  Therefore, the calling terminal notifies the callee terminal of a candidate list of media processing methods that can be used by the calling terminal via a session control server that performs session control. A procedure for determining a media processing method used for communication by selecting a method and returning it to the calling terminal via the server (for example, a proxy server in SIP) is adopted. In addition, the called terminal selects a plurality of methods instead of one method from the notified media processing method candidates, and notifies the calling terminal of the selection results via the server. A procedure is also adopted in which a media processing method to be used is selected from a plurality of received media processing methods and returned to the called terminal.

On the other hand, in a network configuration in which a plurality of call setting protocols are mixed, the session control server converts the candidate list of available media processing methods notified from the calling terminal into a description format of the protocol of the called terminal and arrives. Notify the call terminal. When the media processing method used by the called terminal is selected from the media processing method candidate list and returned to the session control server, the session control server converts the selected contents into the protocol description format of the calling terminal. A procedure is employed in which the calling terminal is notified and the media processing method to be used in the session is determined. Such a session control server (gateway) is disclosed in, for example, an open patent publication (Japanese Patent Laid-Open No. 2001-358778: Patent Document 1).
JP 2001-358778 A

  However, when the processing capability of the terminal device of the called terminal is low, it takes time to analyze the received candidate list of the media processing method, and from the session start request of the calling terminal to the establishment of the call (until the start of media transmission / reception) There is a problem that time becomes long. In particular, in a network with a large delay, the time delay from the session start request to the start of media transmission / reception becomes so large that it cannot be ignored by repeating the procedure for determining the media processing method between terminals.

  In addition, in a session control server in a network configuration in which a plurality of protocols coexist, if the server is realized by a device with low processing capability, it takes time to analyze the media processing method, and media transmission / reception starts from a session start request. There is a problem that the time until is increased.

  The present invention was made to solve such a problem, and by simplifying the procedure for determining the media processing method, a server device capable of reducing the time from the session start request to the start of transmission / reception of media, It is an object to provide a connection method and a computer program.

  In order to achieve the above-described object, the selection device according to the first aspect of the present invention notifies the callee terminal of a plurality of codec method candidates that the caller terminal can use at the time of call setting, A selection apparatus in a communication system for selecting a codec method to be used at the time of communication by a terminal based on a notification, and storing the codec method to be used at the time of communication as a codec method to be used for communication between a calling terminal and a called terminal Means for receiving a call setting request from the calling terminal to the called terminal, transmitting means for transmitting the call setting request to the called terminal, and a codec method to be selected for the call setting request from the called terminal. And a transfer unit that receives the response including the response and transmits the response to the calling terminal, and the storage unit stores the correspondence between the calling terminal and the called terminal included in the call setting request. Case The transmission means deletes a candidate other than the codec scheme indicated by the stored correspondence among the codec scheme candidates included in the call setting request, and when the correspondence is not stored, The codec method included in the answer received by the transfer unit is stored in the storage unit as the codec method used for communication between the calling terminal and the called terminal.

  The conversion apparatus according to the second aspect of the present invention notifies a call setting request of a codec method candidate that can be used by the calling terminal at the time of call setting to a called terminal having a media processing method different from that of the calling terminal. In the communication system in which the called terminal selects a codec method to be used at the time of communication based on the notification, a conversion device that converts a call setting request according to the media processing method, the codec method being used at the time of communication, A storage means for storing the media processing method together with a codec method used for communication between the calling terminal and the called terminal; a receiving means for receiving a call setting request from the calling terminal to the called terminal; and a call setting request Transmitting means for transmitting to the called terminal, and transfer means for receiving a response including a codec method to be selected for the call setting request from the called terminal and transmitting the answer to the calling terminal, When the memory means stores the correspondence of the codec system between the calling terminal and the called terminal included in the call setting request, the transmitting means transmits the call setting request based on the media conversion system stored together with the correspondence. The transfer means converts the received response based on the media conversion method stored together with the correspondence and transmits it. On the other hand, if the correspondence is not stored, the reply is received by the transfer means. The codec system included in the codec system used for communication between the calling terminal and the called terminal is further stored in the storage means together with the media conversion system obtained when setting the call between the calling terminal and the called terminal. It is characterized by memorizing.

  According to a third selection method of the present invention, a caller terminal notifies a plurality of codec method candidates that the caller terminal can use at the time of call setting to the caller terminal, and the callee terminal uses it during communication based on the notification. A codec method selection method in a communication system for selecting a codec method to be used, the step of storing the codec method used at the time of communication in a storage means as a codec method used for communication between a calling terminal and a called terminal; Receiving a call setting request from the calling terminal to the called terminal; transmitting a call setting request to the called terminal; receiving a reply including a codec method to be selected for the call setting request from the called terminal; A step of transferring the answer to the calling terminal, and the step of transmitting stores the correspondence of the codec scheme between the calling terminal and the called terminal included in the call setting request in the storage means. If the codec method candidate included in the call setting request is deleted, a candidate other than the stored codec method indicated by the correspondence is deleted, transmitted, and stored. If not, the codec method included in the response received in the transferring step is stored as a codec method used for communication between the calling terminal and the called terminal.

  In the conversion method according to the fourth aspect of the invention, a codec method candidate that can be used by a calling terminal at the time of call setting is notified as a call setting request to a called terminal having a media processing method different from that of the calling terminal. In the communication system for selecting a codec method to be used at the time of communication based on the notification by the called terminal, a conversion method for converting a call setting request according to the media processing method, the codec method to be used at the time of communication and its Storing a media processing method in a storage unit together with a codec method used for communication between the calling terminal and the called terminal, receiving a call setting request from the calling terminal to the called terminal, and a call setting request Transmitting a response to the call terminal, receiving a response including a codec method to be selected for the call setup request, and transferring the response to the call terminal. If the codec scheme correspondence between the calling terminal and the called terminal included in the call setting request is stored in the storage means, the transmitting step stores the call setting request together with the correspondence. The step of converting, transmitting and transferring based on the conversion method converts and transfers the received answer based on the media conversion method stored together with the correspondence, while storing the correspondence if the correspondence is not stored. In the step of transferring, the codec method included in the response received in the forwarding step is a codec method used for communication between the calling terminal and the called terminal, and at the time of call setting between the calling terminal and the called terminal. It is characterized in that it is stored in a storage means together with the media conversion method obtained in the above.

  A computer program according to a fifth aspect of the present invention notifies a calling terminal of a plurality of codec method candidates that the calling terminal can use at the time of call setting, and the called terminal uses during communication based on the notification. A selection device in a communication system for selecting a codec method, a storage means for storing a codec method used at the time of communication as a codec method used for communication between a calling terminal and a called terminal, and a calling terminal to a called terminal Receiving means for receiving a call setting request to the receiving terminal, transmitting means for transmitting the call setting request to the called terminal, and receiving a reply including a codec method to be selected for the call setting request from the called terminal, Transfer means for transmitting to the calling terminal, and when the storage means stores the correspondence of the codec system between the calling terminal and the called terminal included in the call setting request, the transmitting means Of the codec method candidates included in the fixed request, candidates other than the codec method indicated by the stored correspondence are deleted and transmitted. On the other hand, if the correspondence is not stored, the response received by the transfer means The computer is caused to function as a selection device characterized in that the codec method included in is stored in storage means as a codec method used for communication between the calling terminal and the called terminal.

  The computer program according to the sixth invention notifies a call setting request of a codec method candidate that can be used by the calling terminal at the time of call setting to a called terminal having a media processing method different from that of the calling terminal. In a communication system for selecting a codec method to be used at the time of communication based on the notification by the called terminal, a conversion device that converts a call setting request according to the media processing method, and a codec method to be used at the time of communication A storage means for storing the media processing method together with a codec method used for communication between the calling terminal and the called terminal, a receiving means for receiving a call setting request from the calling terminal to the called terminal, and a call setting request. A transmitting means for transmitting to the called terminal, and a transfer unit for receiving a response including a codec method to be selected for the call setting request from the called terminal and transmitting the response to the calling terminal. And the storage means stores the codec system correspondence between the calling terminal and the called terminal included in the call setting request, the transmission means stores the call setting request together with the correspondence. Based on the conversion method, the data is converted and transmitted, and the transfer means converts the received answer based on the media conversion method stored together with the correspondence and transmits it. On the other hand, if the correspondence is not stored, the forwarding means Is the codec method used for communication between the calling terminal and the called terminal, and the media conversion method obtained when setting the call between the calling terminal and the called terminal. In addition, the computer is made to function as a conversion device characterized by being stored in a storage means.

  According to the present invention, it is possible to simplify the procedure for determining the media processing method and reduce the time from the session start request to the start of media transmission / reception.

  In a real-time communication in a distributed network, the present invention manages a media control method by a server (proxy server) responsible for call control and a gateway connecting networks of different call control protocols, thereby determining a media processing method. Is simplified.

Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the overall configuration of a network to which the present invention is applied.
As shown in FIG. 1, the network N includes a server 1 that performs call setting for real-time communication, and a gateway 2 that connects the virtual first network 5 and the second network 7 using different protocols for call setting procedures. The terminal 3 (3a to 3c) through which the user performs real-time communication and the telephone 4 connected to the terminal 3a are provided. The server 1 is connected to a location server 6 that manages information indicating the location of the terminal 3 performing real-time communication on the network, such as an address.

  The server 1 is a session control server that performs call settings for real-time communication in the first network 5, and is a proxy server constructed by a network-compatible OS such as Linux (registered trademark), for example. The server 1 has a function of receiving a call request from the terminal 3a, for example, and setting a route and a call to the called terminal 3b and the terminal 3c. Further, the media processing method selected by the called terminal 3b according to the media processing method candidate list notified from the calling terminal 3a is associated with the calling terminal 3a and the called terminal 3b. And a function as a selection device for selecting a media processing method suitable for a calling / incoming terminal in a later call setting procedure. Here, the media processing method is a processing method (codec method) for processing data such as audio and images, and corresponds to, for example, an encoding processing method or a compression processing method. As a media processing system used for telephones and the like, ITU-T standard of voice codec, G.I. 711, G.711. 726, G. 729 method is known.

  The gateway 2 is a session control server that performs protocol conversion between the first network 5 and the second network 7, and is a network server constructed by a network-compatible OS such as Linux (registered trademark), for example. When the call setup procedure in the first network 5 and the call setup procedure in the second network 7 are performed in accordance with different protocols, the gateway 2 performs a protocol conversion of the calling procedure to convert the call. It has a function as a device. With this function, a call can be set between the terminal 3a or terminal 3b belonging to the first network 5 and the terminal device 3c belonging to the second network 7. Protocols that include call setup procedures include SIP and H.264. There is a H.323 system. The SIP system is an application layer control protocol of the OSI reference model proposed by the Internet Engineering Task Force (IETF), which is an Internet standardization organization. H. The H.323 system is a protocol group that defines data communication in real-time communication recommended by ITU-T. As with the server 1, the gateway 2 uses the media processing method selected by the called terminal 3c based on the media processing method candidate list notified from the calling terminal 3a as the calling terminal 3a and It also has a function of storing in association with the terminal 3c on the called side and assisting the setting procedure of the media processing method in the subsequent call setting procedure.

  The terminal 3 (3a to 3c) is a terminal device connected to the IP network, such as a personal computer. The terminal 3 has a function as a communication terminal that performs real-time communication. The terminal 4 may be connected to the outside like the terminal 3a shown in FIG. 1, or the terminals 3b and 3c shown in FIG. In this way, the telephone housing may be provided with a terminal device function. The terminal 3 has a function of performing data transmission / reception via the first network 5 and the second network 7 by performing encoding processing and compression processing on data such as voice and images in real time.

  The first network 5 and the second network 7 are distributed networks such as the Internet and a TCP / IP network. The first network 5 and the second network 7 shown in FIG. 1 constitute logically different networks due to differences in protocols. Therefore, both may be physically connected directly.

  The location server 6 is a server device that stores location information of the terminals 3 in the first network 5 and the second network 7. The location server 6 has a function of notifying location information on the network of the terminal 3 in response to a request from the server 1.

  As described above, in the network N according to this embodiment, the server 1 and the gateway 2 perform media processing returned by the called terminals 3b and 3c in response to the media processing method candidate list transmitted from the calling terminal 3a. The system is stored in association with the calling terminal 3a and the called terminals 3b and 3c, and assists the setting procedure of the media processing method in the subsequent call setting procedure, so that the called terminal and the gateway itself in the media processing method setting procedure The burden can be reduced.

Next, the functional configuration of the server according to this embodiment will be described in detail with reference to FIG. FIG. 2 is a diagram illustrating a functional configuration of the server 1. In the following description, a terminal that makes a call will be described as a terminal 3a shown in FIG. 1, and a terminal that similarly receives a call will be described as a terminal 3b.
As shown in FIG. 2, the server 1 according to this embodiment includes a first receiving unit 101, a first encoding scheme selecting unit 102, a first transmitting unit 103, a second receiving unit 104, and a second receiving unit 101. It has an encoding method selection unit 105, a second transmission unit 106, a terminal type storage unit 107, and an encoding method storage unit 108. The first receiving unit 101 and the second receiving unit 104, the first encoding method selecting unit 102 and the second encoding method selecting unit 105, and the first transmitting unit 103 and the second transmitting unit 106 are: Each corresponds to data transmission from the calling side to the called side, and from the called side to the calling side, and has the same internal configuration.

  The first receiving unit 101 and the second receiving unit 104 are receiving means connected to the first network 5. The first receiving unit 101 and the second receiving unit 104 have a function of receiving signals from the calling terminal 3a and the called terminal 3b, respectively.

  The first encoding method selection unit 102 and the second encoding method selection unit 105 are selection means for selecting a media processing method. The first encoding method selection unit 102 and the second encoding method selection unit 105 refer to the terminal type storage unit 107 and the encoding method storage unit 108, and are media processing methods sent from the calling terminal 3a. From the candidate list, the media processing method corresponding to the called terminal 3b is selected and the candidate list is corrected. When the combination of the calling terminal and the called terminal is new, the first encoding method selection unit 102 and the second encoding method selection unit 105 determine the media processing method selected by the called terminal. The terminal type storage unit 107 and the encoding method storage unit 108 also have a function of storing them in correspondence with the type of calling terminal and the type of called terminal, respectively.

  The first transmission unit 103 and the second transmission unit 106 are transmission units connected to the first network 5. The first transmission unit 103 and the second transmission unit 106 transmit the media processing method selected by the first encoding method selection unit 102 and the second encoding method selection unit 105 to the called terminal, or It has a function to send a reply to the calling terminal.

  The terminal type storage unit 107 is a memory unit that associates a calling terminal and a called terminal and stores the types, and the encoding method storage unit 108 is a calling terminal stored in the terminal type storage unit 107. And a memory means for storing each type of the called terminal and the media processing method selected by the called terminal in association with each other. Note that “terminal type” or “terminal type” refers to a classification of terminals that can select the same media processing method. In other words, even if the terminal is from a different manufacturer, it can be “same type” as long as it can take the same type of media processing method. “Different types”. When the called terminal 3b selects a method to be adopted from the media processing method candidate list issued by the calling terminal 3a, the terminal type storage unit 107 corresponds to the types of the calling terminal 3a and the called terminal 3b. The encoding method storage unit 108 has a function of storing the media processing method selected in association with the terminal type stored in the terminal type storage unit 107.

  Next, the operation of the server 1 according to this embodiment will be described with reference to FIGS. FIG. 3 is a flowchart showing the operations of the calling terminal 3a, the server 1, and the called terminal 3b in parallel in this embodiment. FIG. 4 is a diagram showing an example of a media processing method candidate list transmitted from the calling terminal 3a.

  When the terminal 3a makes a call, the terminal 3a transmits a connection request (INVITE request) to the terminal 3b to the server 1 (step S101, hereinafter referred to as “S101”). At this time, the terminal 3a adds a media processing method candidate list that it can handle to the connection request signal and transmits it. Here, as shown in FIG. 711, G.711. 726 and G.726. The description will be made assuming that the three audio codecs of the 729 system are candidates for the media processing system transmitted by the terminal 3a.

  The first receiving unit 101 receives the connection request signal from the terminal 3 a and the media processing scheme candidate list and passes them to the first encoding scheme selection unit 102. The first encoding scheme selection unit 102 refers to the terminal type storage unit 107 and confirms whether or not there is a past connection between the type of the terminal 3a and the type of the terminal 3b. When both terminals have not connected in the past, the first encoding method selection unit 102 passes the connection request signal and the media processing method candidate list received from the terminal 3 a to the first transmission unit 103 as they are. The first transmission unit 103 confirms the location of the terminal 3b by the location server 6, and transmits the received connection request signal and media processing method candidate list to the terminal 3b which is the called terminal (S102).

  The terminal 3b that has received the connection request signal selects the media processing method that it adopts from the media processing method candidate list shown in FIG. 4A (S103). Here, the terminal 3b uses the G.D. Assume that the 726 method is selected.

  When the media processing method is selected, the terminal 3b sends a connection OK response to the server 1 and G. 726 method is answered (S104).

  The second reception unit 104 receives the answer from the terminal 3 b and passes it to the second encoding method selection unit 105. The second encoding scheme selection unit 105 selects the types of the calling terminal 3a and the called terminal 3b and the selected G.D. 726 methods are associated with each other and stored in the terminal type storage unit 107 and the encoding method storage unit 108, respectively (S105).

  When the media processing method selected by the terminal 3b is stored, the second encoding method selection unit 105 passes the connection OK response returned by the terminal 3b and the selected media processing method to the second transmission unit 106. The second transmission unit 106 transmits the received connection OK response and the selected media processing method to the terminal 3a (S106).

  When the connection OK response and the selected media processing method are received, the terminal 3a receives the G. The 726 method is set as the voice codec method, and communication with the terminal 3b is started (S107). When the communication is completed, the connection is released (S108).

  Thereafter, when a terminal of the same type as the terminal 3a (hereinafter referred to as the terminal 3a) issues a connection request to a terminal of the same type as the terminal 3b (hereinafter referred to as the terminal 3b), the terminal 3a, as in step S101, The media processing method candidate list shown in FIG. 4A is added to the connection request signal and transmitted (S109).

  The first receiving unit 101 receives the connection request and the candidate list from the terminal 3 a and passes them to the first encoding scheme selection unit 102. The first encoding scheme selection unit 102 refers to the terminal type storage unit 107 and confirms whether or not there is a past connection between the type of the terminal 3a and the type of the terminal 3b. Since the terminal type storage unit 107 stores the connection record between the terminal 3a and the terminal 3b, the first encoding method selection unit 102 uses the media processing method (used for communication between the terminal 3a and the terminal 3b ( The media processing method selected by the called terminal 3b is read from the encoding method storage unit 108 (S110). Here, the G. stored in step S105. The 726 method is read out.

  When the media processing method is read from the encoding method storage unit 108, the first encoding method selection unit 102 reads the code from the media processing method candidate list transmitted by the terminal 3a as shown in FIG. A method other than the media processing method read out from the data storage method storage unit 108 is deleted (deletion process). FIG. 4B shows a G. format read from the encoding method storage unit 108 from the candidate list of the terminal 3a. A state in which a method other than the 726 method is deleted is shown. When the deletion process is performed, the first encoding scheme selection unit 102 passes the connection request signal received from the terminal 3a and the media processing scheme candidate list subjected to the deletion process to the first transmission unit 103. . The first transmission unit 103 confirms the location of the terminal 3b by the location server 6, and transmits the received connection request signal and the candidate list of the media processing method that has been deleted to the terminal 3b that is the called terminal (S111). .

  The terminal 3b that has received the connection request signal selects the media processing method adopted by itself from the media processing method candidate list (S112). Here, in the media processing method candidate list, the G.G. Only the 726 method is included. Therefore, the terminal 3b uses the G.D. The 726 method is selected as it is.

  When the media processing method is selected, the terminal 3b sends a connection OK response to the server 1 and G. The 726 method is answered (S113).

  The second reception unit 104 receives the answer from the terminal 3 b and passes it to the second encoding method selection unit 105. The second encoding scheme selection unit 105 selects the types of the calling terminal 3a and the called terminal 3b and the selected G.D. 726 methods are associated with each other and stored in the terminal type storage unit 107 and the encoding method storage unit 108, respectively. Here, since the media processing method selected by the terminal 3b is the same as the method already stored in the encoding method storage unit 108, the second encoding method selection unit 105 simply confirms the contents (S114). . When the terminal 3b responds with a different media processing method, the newly replied media processing method is stored as the latest media processing method.

  The second encoding method selection unit 105 passes the connection OK response returned by the terminal 3 b and the selected media processing method to the second transmission unit 106. The second transmission unit 106 transmits the received connection OK response and the selected media processing method to the terminal 3a (S115).

  When the connection OK response and the selected media processing method are received, the terminal 3a receives the G. The 726 method is set as the voice codec method, and communication with the terminal 3b is started (S116). When the communication is completed, the connection is released (S117).

  In the above description, the terminal 3b selects only one media processing method from the media processing method candidate list, but the present invention is not limited to this. That is, the called terminal 3b may select a plurality of media processing methods from the candidate list. In this case, the calling terminal 3a selects one media processing method from among the plurality of media processing methods selected by the terminal 3b, and the first encoding method selection unit 102 selects the one media processing method. The system is stored in the encoding system storage unit 108.

  Further, until one media processing method is determined between the calling terminal 3a and the called terminal 3b, the calling terminal 3a and the called terminal 3b repeatedly select and answer the media processing method from the candidate list. Also good. In this case, if either the first encoding method selection unit 102 or the second encoding method selection unit 105 stores the media processing method finally narrowed down to one in the encoding method storage unit 108. Good.

  As described above, the server 1 according to this embodiment stores the caller terminal type, the callee terminal type, and the media processing method selected by the callee terminal so as to correspond to each other, and A method other than the media processing method selected in the past is deleted from the media processing method candidate list in the connection request. Once information on the terminal type and the selected media processing method is stored in the server 1, the called terminal receives a presentation with only the media processing method selected in the past as candidates. Therefore, since the processing amount of the media processing method selection of the called terminal can be reduced, the time delay from connection request to connection establishment can be minimized even when the processing capacity of the called terminal is relatively low. In particular, since a terminal does not require a special configuration, it can be easily applied to a network including existing terminals.

  Even if a plurality of exchanges are required for determining the media processing method between the calling terminal and the called terminal, the finally narrowed media processing method is stored in the encoding method storage unit 108. Then, since the stored media processing method is a method that can be accepted by either terminal, a plurality of exchanges are not required in the subsequent call setting. Therefore, the time delay from connection request to connection establishment can be minimized.

  Furthermore, since the server 1 according to this embodiment stores a media processing method such as a data compression method corresponding to the combination of the calling terminal and the called terminal, the server 1 stores the call when the combination is called. It is possible to force the called media processing method to the calling terminal and the called terminal. That is, the data compression rate can be controlled by selecting the media processing method, and the bandwidth of the communication line between the calling terminal and the called terminal can be controlled.

  Next, the gateway according to the second embodiment of the present invention will be described in detail with reference to FIG. FIG. 5 is a diagram illustrating a functional configuration of the gateway 2. In the following description, a terminal that makes a call will be described as a terminal 3a shown in FIG. 1, and a terminal that makes a call will be described as a terminal 3c. The gateway 2 according to this embodiment is similar to the first network 5 that employs the SIP method as a calling method, The second network 7 adopting the H.323 system has a function that enables mutual call setting.

  As shown in FIG. 5, the gateway 2 according to this embodiment includes a SIP receiving unit 201, a SIP encoding method selecting unit 202, a SIP → H. H.323 converter 203, and H.323. 323 transmission unit 204 is provided. Similarly, this gateway 2 is an H.264 network responsible for communication from the called terminal 3c to the calling terminal 3a. H.323 receiver 205, H.323. H.323 encoding method selection unit 206, H.323. 323 → SIP converter 207 and SIP transmitter 208. Further, the gateway 2 includes a SIP encoding method storage unit 212, SIP → H. H.323 conversion storage unit 211, H.323. H.323 encoding method storage unit 210, H.323. 323 → SIP conversion storage unit 209 and terminal type storage unit 213.

  The SIP receiving unit 201 is a receiving unit that receives a signal from the terminal 3a that performs call processing by the SIP method. The H.323 reception unit 205 is connected to the H.323 receiver. It is a receiving means for receiving a signal from the terminal 3c that performs call processing by the H.323 system. SIP receiving unit 201 and H.264 The H.323 receiving unit 205 is connected to the first network 5 and the second network 7 that constitute logically different networks, but may exist on the same physical network.

  When the SIP terminal 3a is the calling terminal, the SIP encoding method selection unit 202 selects H.264 from the media processing method candidate list issued by the terminal 3a. This is a selection means for selecting a media processing method suitable for the 323-type incoming call terminal 3c. H. The H.323 encoding method selection unit 206 is an H.323 encoding method. When the H.323 terminal 3c is a calling terminal, it is a selection means for selecting a media processing method suitable for the SIP called terminal 3a from a candidate list of media processing methods issued by the terminal 3c. SIP encoding scheme selection unit 202 and H.264 The H.323 encoding method selection unit 206 includes the SIP encoding method storage unit 212 and the H.323 encoding method. With reference to the H.323 encoding method storage unit 210, the media processing method corresponding to the called terminal is selected from the media processing method candidate list sent from the calling terminal, and the candidate list is corrected.

  SIP → H. The H.323 conversion unit 203 converts the connection request and media processing method described in the SIP method to H.323. This is protocol conversion means for converting to the H.323 system. H. The H.323 → SIP conversion unit 207 is an H.323. This is protocol conversion means for converting a connection request or media processing system described in the H.323 system to the SIP system. SIP → H. H.323 converter 203 and H.323 converter. The H.323 → SIP conversion unit 207 converts the descriptions of the converted media processing methods into SIP → H. H.323 conversion storage unit 211 and H.323 conversion storage unit 211. 323 → SIP conversion storage unit 209 also has a function of storing.

  H. The H.323 transmission unit 204 is connected to the H.323 transmission unit. The SIP transmission unit 208 is a transmission unit that transmits a signal to the terminal 3a that performs call processing by the SIP method. H. The H.323 transmission unit 204 and the SIP transmission unit 208 are connected to the second network 7 and the first network 5 that constitute logically different networks, respectively, but may exist on the same physical network. Good.

  The terminal type storage unit 213 is a memory unit that associates a calling terminal and a called terminal and stores the types, and corresponds to the terminal type storage unit 107 in the first embodiment. In addition, the SIP encoding method storage unit 212 and the H.264 standard. The H.323 encoding method storage unit 210 is a memory unit that stores the types of the calling terminal and the called terminal stored in the terminal type storage unit 213 in association with the media processing method selected by the called terminal. Yes, corresponding to the encoding method storage unit 108 in the first embodiment. Furthermore, SIP → H. H.323 conversion storage unit 211 and H.323 conversion storage unit 211. The H.323 → SIP conversion storage unit 209 stores the SIP → H. H.323 converter 203 and H.323 converter. 323 is a memory means for storing a description of the media processing method converted by the SIP conversion unit 207.

  Next, the operation of the gateway 2 according to this embodiment will be described with reference to FIGS. 5 and 6. FIG. 6 is a flowchart showing the operations of the calling terminal 3a, the gateway 2, and the called terminal 3c in parallel in this embodiment.

  When the terminal 3a makes a call, the terminal 3a transmits a connection request (INVITE request) to the terminal 3c to the gateway 2 (S201). At this time, the terminal 3a adds a media processing method candidate list that it can handle to the connection request signal and transmits it. Here, as in the first embodiment, G.I. 711, G.711. 726 and G.726. The description will be made assuming that the three audio codecs of the 729 system are candidates for the media processing system transmitted by the terminal 3a.

  The SIP receiving unit 201 receives the connection request signal from the terminal 3 a and the media conversion method candidate list, and passes them to the SIP encoding method selection unit 202. The SIP encoding method selection unit 202 refers to the terminal type storage unit 213 and confirms whether or not there is a past connection between the type of the terminal 3a and the type of the terminal 3c. When both terminals have not connected in the past, the SIP encoding method selection unit 202 uses the connection request signal and the media processing method candidate list received from the terminal 3a as they are. It is passed to the H.323 conversion unit 203. SIP → H. The H.323 conversion unit 203 converts the received connection request signal and candidate list into the H.323 format. H.323 H.323. Convert to H.225 procedure To the H.323 transmission unit 204. H. The H.323 transmission unit 204 confirms the location of the terminal 3c by the location server 6, and transmits the received connection request signal and candidate list to the terminal 3c that is the called terminal (S202).

  The terminal 3c that has received the connection request signal and the candidate list selects the media processing method that it adopts from the media processing method candidate list (S203). Here, the terminal 3c uses G.P. Assume that the 711 method is selected. The terminal 3c selects a media processing method by the first connect procedure.

  When the media processing method is selected, the terminal 3c sends a connection OK response to the gateway 2 and selects G.G as the selected media processing method. 711 method is answered (S204).

  H. The H.323 reception unit 205 receives the answer from the terminal 3c, It is passed to the H.323 encoding method selection unit 206. H. The H.323 encoding method selection unit 206 stores the types of the calling terminal 3a and the called terminal 3c in association with each other in the terminal type storage unit 213. When the types of the terminals 3a and 3c are stored, H.264 is stored. The H.323 encoding method selection unit 206 sets the response of connection OK returned by the terminal 3c and the selected media processing method to H.323. 323 to SIP conversion unit 207. H. The H.323 → SIP conversion unit 207 converts the received data into the SDP format which is the description of the SIP system (S205).

  Once the data has been converted, The H.323 → SIP conversion unit 207 associates the type of the calling terminal and the called terminal with the description of the procedure of the calling terminal of the media processing method and the procedure of the called terminal, respectively. 323 → Stores in the SIP conversion storage unit 209. Then, the converted connection OK response and the selected media processing method are transferred to the IP transmission unit 208. The SIP transmitting unit 208 transmits the converted connection OK response and the selected media processing method to the terminal 3a (S206). H. When the converted media processing method description is stored in the 323 → SIP conversion storage unit 209, the content is transferred to the SIP encoding method storage unit 212.

  Upon receipt of the converted connection OK reply and the selected media processing method, the terminal 3a receives the G. The 711 method is set as the voice codec method, and communication with the terminal 3c is started (S207). At this time, the gateway 2 converts the protocol of the call setup procedure signal as necessary (S208). When the communication is completed, the connection is released (S209).

  Thereafter, when a terminal of the same type as the terminal 3a (hereinafter referred to as the terminal 3a) issues a connection request to a terminal of the same type as the terminal 3c (hereinafter referred to as the terminal 3c), the terminal 3a, as in step S201, The media processing method candidate list is added to the connection request signal and transmitted (S210).

  The SIP receiving unit 201 receives the connection request signal from the terminal 3 a and the media processing method candidate list and passes them to the SIP encoding method selecting unit 202. The SIP encoding method selection unit 202 refers to the terminal type storage unit 213 and confirms whether or not there is a past connection between the type of the terminal 3a and the type of the terminal 3c. Since the terminal type storage unit 213 stores the connection record between the terminal 3a and the terminal 3c, the SIP encoding method selection unit 202 uses the media processing method (incoming call) used in the communication between the terminal 3a and the terminal 3c. The media processing method selected by the terminal 3c) is read from the SIP encoding method storage unit 212 (S211). Here, in step S206, H.264 is recorded. 323 → G.G transferred from the SIP conversion storage unit 209. 711 method is read out.

  When the media processing method is read from the SIP encoding method storage unit 212, the SIP encoding method selection unit 202 reads the media read from the SIP encoding method storage unit 212 from the media processing method candidate list transmitted by the terminal 3a. Delete methods other than the processing method (deletion processing). When the deletion process is performed, the SIP encoding method selection unit 202 converts the connection request signal received from the terminal 3a and the candidate list of the media processing method subjected to the deletion process to SIP → H. It is passed to the H.323 conversion unit 203. SIP → H. The H.323 conversion unit 203 is connected to the H.323 via the SIP encoding method storage unit 212. 323 → SIP conversion storage unit 209 is referred to, and the transferred data is converted to H.323. H.323 system is converted to H.323 format. To the H.323 transmission unit 204. H. The H.323 transmission unit 204 confirms the location of the terminal 3c by the location server 6, and transmits the received connection request signal and the deleted media processing method candidate list to the terminal 3c that is the called terminal (S212).

  The terminal 3c that has received the connection request signal and the media processing method candidate list selects the media processing method it adopts from the candidate list (S213). Here, in the media processing method candidate list, the G.G. data previously selected by the terminal 3c and finally stored in the SIP encoding method storage unit 212 are stored. Only the 711 system is included. Therefore, the terminal 3c uses the G.D. The 711 method is selected as it is.

  When the media processing method is selected, the terminal 3c returns a connection OK response to the gateway 2 and uses the selected G.G. 711 method is answered (S214).

  H. The H.323 reception unit 205 receives the answer from the terminal 3c, It is passed to the H.323 encoding method selection unit 206. H. The H.323 encoding method selection unit 206 stores the types of the calling terminal 3 a and the called terminal 3 c in association with each other in the terminal type storage unit 107. Here, the combination of the terminal 3a and the terminal 3c is already stored. The H.323 encoding method selection unit 206 simply confirms the contents, sets the reply of connection OK and the selected media processing method to H.323. 323 to SIP conversion unit 207. H. The H.323 → SIP conversion unit 207 converts the received data into a SIP description (S215).

  Once the data has been converted, The H.323 → SIP conversion unit 207 converts the description of the converted SIP media processing method to H.323. 323 → Stores in the SIP conversion storage unit 209. Here, H. Since the description of the media processing method selected in the past is stored in the H.323 → SIP conversion storage unit 209, H.323. The H.323 → SIP conversion unit 207 simply confirms the contents. When the terminal 3c responds with a different media processing method, a description of the newly replied media processing method is stored as the latest media processing method. H. The H.323 → SIP conversion unit 207 passes the connection OK response returned by the terminal 3c and the selected media processing method to the SIP transmission unit 208. The SIP transmission unit 208 transmits the received connection OK response and the selected media processing method to the terminal 3a (S216).

  When the connection OK response and the selected media processing method are received, the terminal 3a receives the G. The 711 method is set as the voice codec method, and communication with the terminal 3c is started (S217). At this time, the gateway 2 converts the protocol of the call setup procedure signal as necessary (S208). When the communication is completed, the connection is released (S219).

  In the above description, the terminal 3c selects only one media processing method from the media processing method candidate list, but the present invention is not limited to this. That is, the called terminal 3c may select a plurality of media processing methods from the candidate list. In this case, the calling terminal 3a selects one media processing method from the plurality of media processing methods selected by the terminal 3c, and SIP → H. The H.323 conversion unit 203 changes the media processing method narrowed down to one to SIP → H. Stored in the H.323 conversion storage unit 211.

  Further, until one media processing method is determined between the calling terminal 3a and the called terminal 3c, the calling terminal 3a and the called terminal 3c repeatedly select and answer the media processing method from the candidate list. Also good. In this case, SIP → H. H.323 converter 203 or H.323. Any one of the H.323 → SIP conversion unit 207 selects the media processing method finally narrowed down to SIP → H. H.323 conversion storage unit 211 or H.323. What is necessary is just to memorize | store in 323-> SIP conversion memory | storage part 209.

  As described above, the gateway 2 according to this embodiment stores the caller terminal type and the callee terminal type, and also the media processing method selected by the callee terminal corresponding to the terminal type. In the connection request between the same kind of terminals, a method other than the media processing method selected in the past is deleted from the media processing method candidate list. Then, once information on the terminal type and the selected media processing method is stored in the gateway 2, the called terminal receives presentation with only the media processing method selected in the past as candidates. Therefore, since the processing amount of the media processing method selection of the called terminal can be reduced, the time delay from connection request to connection establishment can be minimized even when the processing capacity of the called terminal is relatively low. In particular, since a terminal does not require a special configuration, it can be easily applied to a network including existing terminals.

  Further, even when a plurality of exchanges are required for determining the media processing method between the calling terminal and the called terminal, when the finally narrowed media processing method is stored, the stored media Since the processing method is acceptable to both terminals, a plurality of exchanges are not necessary thereafter. Therefore, the time delay from connection request to connection establishment can be minimized.

  Furthermore, the gateway 2 according to this embodiment stores a media processing method such as a data compression method corresponding to the combination of the calling terminal and the called terminal, so that it is stored when a call of the combination is made. It is possible to force the called media processing method to the calling terminal and the called terminal. That is, the data compression rate can be controlled by selecting the media processing method, and the bandwidth of the communication line between the calling terminal and the called terminal can be controlled.

  In addition, since the gateway 2 according to this embodiment stores a description of a media processing method such as a data compression method corresponding to a combination of a calling terminal and a called terminal, the stored description is stored in a later call setting. Protocol conversion can be performed simply by reading. That is, even when the processing capability of the gateway 2 itself is not high, the time delay from the connection request to the connection establishment can be minimized.

  The present invention can be applied to telecommunications business, telecommunications equipment manufacturing industry, and the like.

It is a figure which shows the whole network structure to which this invention is applied. It is a figure which shows the function structure of the server which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the server which concerns on this embodiment. It is a figure which shows the example of the candidate list of the media processing system in this embodiment. It is a figure which shows the function structure of the gateway which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the gateway which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Server, 2 ... Gateway, 3 ... Terminal, 4 ... Telephone, 5 ... 1st network, 6 ... Location server, 7 ... 2nd network,
DESCRIPTION OF SYMBOLS 101 ... 1st receiving part, 102 ... 1st encoding system selection part, 103 ... 1st transmission part, 104 ... 2nd receiving part, 105 ... 2nd encoding system selection part, 106 ... 2nd Transmitting unit 107 ... terminal type storage unit 108 ... encoding method storage unit,
201... SIP receiving unit, 202... SIP encoding method selection unit, 203... SIP to H.323 conversion unit, 204. 323 transmitter, 205. 323 reception unit, 206. 323 encoding method selection unit, 207. 323 → SIP conversion unit, 208... SIP transmission unit, 209. 323 → SIP conversion storage unit, 210. 323 encoding method storage unit 211... SIP → H. 323 conversion storage unit, 212... SIP encoding method storage unit, 213... Terminal type storage unit.

Claims (6)

Selection in a communication system in which a calling terminal notifies a plurality of codec method candidates that the calling terminal can use at the time of call setup to the called terminal, and the called terminal selects a codec method to be used during communication based on the notification A device,
Storage means for storing a codec method used at the time of communication as a codec method used for communication between the calling terminal and the called terminal;
Receiving means for receiving a call setup request from the calling terminal to the called terminal;
Transmitting means for transmitting the call setting request to the called terminal;
Receiving a response including a codec method to be selected for the call setup request from the called terminal, and comprising a transfer means for transmitting the response to the calling terminal.
When the storage means stores the correspondence of the codec method between the calling terminal and the called terminal included in the call setting request, the transmitting means includes the codec method candidates included in the call setting request. , Delete the candidate other than the codec method indicated by the stored correspondence, and transmit,
On the other hand, if the correspondence is not stored, the codec method included in the response received by the transfer unit is stored in the storage unit as the codec method used for communication between the calling terminal and the called terminal. A selection device characterized by: When a call is set up, the calling terminal notifies a call setting request of a codec method candidate that can be used by the calling terminal to a called terminal having a media processing method different from that of the calling terminal. In a communication system that selects a codec method to be used at the time of communication based on the media processing method, the conversion device converts the call setting request according to the media processing method,
Storage means for storing the codec method used during the communication and the media processing method together with the codec method used for communication between the calling terminal and the called terminal;
Receiving means for receiving a call setup request from the calling terminal to the called terminal;
Transmitting means for transmitting the call setting request to the called terminal;
Receiving a response including a codec method to be selected for the call setup request from the called terminal, and comprising a transfer means for transmitting the response to the calling terminal.
When the storage unit stores the correspondence of the codec system between the calling terminal and the called terminal included in the call setting request,
The transmission means converts the call setting request based on the media conversion method stored together with the correspondence and transmits the call setting request, and the transfer means converts the received answer based on the media conversion method stored together with the correspondence. Send
On the other hand, if the correspondence is not stored, the codec method included in the response received by the transfer means is the codec method used for communication between the calling terminal and the called terminal, and further, the calling A conversion apparatus, characterized in that the storage means stores the media conversion method obtained at the time of call setting between a call terminal and the called terminal. Codec in a communication system in which a calling terminal notifies a plurality of codec method candidates that the calling terminal can use at the time of call setting to the called terminal, and the called terminal selects a codec method to be used during communication based on the notification A method of selecting a method,
Storing the codec method used at the time of communication in a storage means as a codec method used for communication between the calling terminal and the called terminal;
Receiving a call setup request from the calling terminal to the called terminal;
Transmitting the call setup request to the called terminal;
Receiving a response including a codec scheme to be selected for the call setup request from the called terminal and transferring the response to the calling terminal.
In the transmitting step, when the storage means stores the correspondence of the codec schemes of the calling terminal and the called terminal included in the call setting request, the codec scheme candidates included in the call setting request Among these, the candidate other than the codec method indicated by the stored correspondence is deleted and transmitted,
In the storing step, when the correspondence is not stored, the codec method included in the answer received in the transferring step is stored as a codec method used for communication between the calling terminal and the called terminal. A selection method characterized by: When a call is set up, the calling terminal notifies a call setting request of a codec method candidate that can be used by the calling terminal to a called terminal having a media processing method different from that of the calling terminal. In a communication system for selecting a codec method to be used based on communication, a conversion method for converting the call setting request according to the media processing method,
Storing the codec method used in the communication and the media processing method in a storage unit together with the codec method used for communication between the calling terminal and the called terminal;
Receiving a call setup request from the calling terminal to the called terminal;
Transmitting the call setup request to the called terminal;
Receiving an answer including a codec scheme to be selected for the call setup request from the called terminal, and transferring the answer to the calling terminal;
Have
When the storage means stores the correspondence of the codec method between the calling terminal and the called terminal included in the call setting request,
The transmitting step converts the call setup request based on the media conversion method stored with the correspondence and transmits the request, and the forwarding step is based on the media conversion method stored with the response. Convert and transfer
On the other hand, if the correspondence is not stored, the storing step uses the codec method included in the answer received in the transferring step for communication between the calling terminal and the called terminal. A conversion method further comprising: storing in the storage unit together with a media conversion method obtained when setting a call between the calling terminal and the called terminal. Selection in a communication system in which a calling terminal notifies a plurality of codec method candidates that the calling terminal can use at the time of call setup to the called terminal, and the called terminal selects a codec method to be used during communication based on the notification A device,
Storage means for storing a codec method used at the time of communication as a codec method used for communication between the calling terminal and the called terminal;
Receiving means for receiving a call setup request from the calling terminal to the called terminal;
Transmitting means for transmitting the call setting request to the called terminal;
Receiving a response including a codec method to be selected for the call setup request from the called terminal, and comprising a transfer means for transmitting the response to the calling terminal.
When the storage means stores the correspondence of the codec method between the calling terminal and the called terminal included in the call setting request, the transmitting means includes the codec method candidates included in the call setting request. , Delete the candidate other than the codec method indicated by the stored correspondence, and transmit,
On the other hand, if the correspondence is not stored, the codec method included in the response received by the transfer unit is stored in the storage unit as the codec method used for communication between the calling terminal and the called terminal. A computer program for causing a computer to function as a selection device. When a call is set up, the calling terminal notifies a call setting request of a codec method candidate that can be used by the calling terminal to a called terminal having a media processing method different from that of the calling terminal. In a communication system that selects a codec method to be used at the time of communication based on the media processing method, the conversion device converts the call setting request according to the media processing method,
Storage means for storing the codec method used during the communication and the media processing method together with the codec method used for communication between the calling terminal and the called terminal;
Receiving means for receiving a call setup request from the calling terminal to the called terminal;
Transmitting means for transmitting the call setting request to the called terminal;
Receiving a response including a codec method to be selected for the call setup request from the called terminal, and comprising a transfer means for transmitting the response to the calling terminal.
When the storage unit stores the correspondence of the codec system between the calling terminal and the called terminal included in the call setting request,
The transmission means converts the call setting request based on the media conversion method stored together with the correspondence and transmits the call setting request, and the transfer means converts the received answer based on the media conversion method stored together with the correspondence. Send
On the other hand, if the correspondence is not stored, the codec method included in the response received by the transfer means is the codec method used for communication between the calling terminal and the called terminal, and further, the calling A computer program for causing a computer to function as a conversion device, which is stored in the storage unit together with a media conversion method obtained at the time of call setting between a call terminal and the called terminal.

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