Patent Publication Number: US-2005117599-A1

Title: Network telephone system, main apparatus for the same system and connection information update method using the same system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2003-400899, filed Nov. 28, 2003, the entire contents of which are incorporated herein by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a network telephone system such as Internet Protocol (IP) telephone system, which makes voice communications between telephone terminals via IP network. In addition, the present invention relates to a main apparatus for the foregoing network telephone system, and a connection information update method using the same system.  
      2. Description of the Related Art  
      In recent years, a network telephone system (IP telephone system) has come into wise use. According to the network telephone system, image and voice are bi-directionally received and transmitted as packet data in real time via packet network. In the IP telephone system, communications between extensions and sending/receiving of an outside call are made for each main apparatus connected to packet network. In addition, communications between extensions and sending/receiving of an outside call are made between main apparatuses via the packet network.  
      In the foregoing IP telephone system, an IP address of the main apparatus is previously registered for each main apparatus in order to make communications between extensions and sending/receiving of the outside call. When making communications, the sender main apparatus and the receiver main apparatus are connected via the packet network based on the registered IP address.  
      However, according to the IP telephone system, if there exist several roots from the sender main apparatus to the receiver main apparatus, IP addresses for these roots must be manually registered. As a result, setup and registration are very troublesome. Moreover, the setup and registration of each IP address of the main apparatus must be made once more from the beginning every when a change of numbering plan and a system change such as increase of the main apparatus are carried out. As a result, much time and labor are taken to the maintenance.  
      In order to solve the foregoing problem, the following system has been proposed (for example, JPN. PAT. APPLN. KOKAI Publication No. 2003-198724). According to the system, a server for collectively managing the IP address of each main apparatus is provided on the packet network. The sever queries the IP address with respect to each main apparatus every predetermined period, and if a change of the IP address is made, automatically updates the IP address.  
      However, the foregoing system has the problem described below. For example, if a fault occurs in the server, communications via packet network are not quite made until the fault is released. In addition, the packet network is occupied while the sever queries the IP address with respect to each main apparatus. This is a factor of giving an influence to voice packet transmission.  
     BRIEF SUMMARY OF THE INVENTION  
      Therefore, an object of the present invention is to provide a network telephone system, which can simply IP address setup and registration resulting from a system change using packet network in a short time, and reduce load to the packet network. In addition, another object of the present invention is to provide a main apparatus for the network telephone system, and to a connection information update method using the same system.  
      According to an aspect of the present invention, there is provided a network telephone system connected via a communication network between a plurality of main apparatuses including at least one telephone terminal, at least one of the main apparatuses communicating with other main apparatus via the communication network, the main apparatuses each comprising: a memory which stores connection information and identification information, the connection information includes information for making a connection to the other main apparatus and the identification information includes information for receiving a connection from the other main apparatus; a connecter which connects to the other main apparatus via the communication network based on the connection information on the memory, when the identification information on the memory is updated; a transmitter which transmits the updated identification information as the connection information to the other main apparatus; and an update circuit to update storage contents of the corresponding connection information on the memory, when receiving updated connection information from the other main apparatus.  
      According to another aspect of the present invention, there is provided a main apparatus used for a network telephone system connected via a communication network between a plurality of main apparatuses including at least one telephone terminal, at least one of the main apparatuses communicating with other main apparatus via the communication network, comprising: a memory which stores connection information and identification information, the connection information includes information for making a connection to the other main apparatus and the identification information includes information for receiving a connection from the other main apparatus; a connecter which connects to the other main apparatus via the communication network based on the connection information on the memory, when the identification information on the memory is updated; a transmitter which transmits the updated identification information as the connection information; and an update circuit to update storage contents of the corresponding connection information on the memory, when receiving updated connection information from the other main apparatus.  
      According to yet another aspect of the present invention, there is provided a method using a network telephone system connected via a communication network between a plurality of main apparatuses including at least one telephone terminal, at least one of the main apparatuses communicating with other main apparatus via the communication network, comprising: storing connection information for making a connection to the other main apparatus and identification information for receiving a connection from the other main apparatus in a memory in each main apparatus; connecting the other main apparatus via the communication network based on the connection information on the memory, when the identification information on the memory is updated; transmitting updated self-identification information as the connection information; and updating storage content of the corresponding connection information on the memory, when updated connection information is received from the other main apparatus.  
      Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
      The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.  
       FIG. 1  is a schematic view showing the configuration of a network telephone system according to a first embodiment of the present invention;  
       FIG. 2  is a block diagram showing the functional configuration of a main apparatus in the first embodiment;  
       FIG. 3  is a view showing storage contents of a storage section shown in  FIG. 2 ;  
       FIG. 4  is a view to explain the procedure of the transmitting/receiving operation when a connection is made between main apparatuses in the first embodiment;  
       FIG. 5  is a flowchart to explain the operation by a control section when the connection to another main apparatus is made in the first embodiment;  
       FIG. 6  is a flowchart to explain the operation by the control section when a changed IP address arrives from another main apparatus in the first embodiment;  
       FIG. 7  is a view to explain the procedure of the transmitting/receiving operation when connection is made between main apparatuses in a network telephone system according to a second embodiment of the present invention;  
       FIG. 8  is a block diagram to explain the operation of updating an IP address for each group in a network telephone system according to a third embodiment of the present invention; and  
       FIG. 9  is a view showing the storage content of a group management table. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Embodiments of the present invention will be described below with reference to the accompanying drawings.  
     First Embodiment  
       FIG. 1  is a schematic view showing the configuration of a network telephone system according to a first embodiment of the present invention.  
      The network telephone system has a Local Area Network (LAN)  1 . The LAN  1  is connected with several main apparatuses BT 1  to BTn (n is a natural number). The apparatuses BT 1  to BTn are connected with telephone terminals T 11  to T 1   i  (i is a natural number) to Tn 1  to Tnj (j is a natural number), respectively.  
      The apparatuses BT 1  to BTn each have the following function according to the present invention.  FIG. 2  is a block diagram showing the functional configuration. In this case, the main apparatus BT 1  will be explained below as the typical example.  
      The main apparatus BT 1  includes time switch (hereinafter, referred to as TSW)  11 , LAN interface (LAN I/F)  12 , extension interface (extension I/F)  13 , control section  14 , storage section  15 , voice gateway (voice GW)  16  and timer  17 . The foregoing TSW  11 , LAN I/F  12 , and extension I/F  13  are mutually connected via a PCM highway  18 . In addition, the foregoing TSW  11 , LAN I/F  12 , and extension I/F  13  are mutually connected via a data highway  19 .  
      The foregoing control section  14 , storage section  15 , voice GW  16  and timer  17  are connected via a CPU bus  20 . Incidentally, the TSW  11  is connected directly to the control section  14 .  
      The TSW  11  make a replacement of time slot on the PCM highway  18  based on the control by the control section  14 , and thereby, arbitrarily makes an exchange between LAN IF  12  and extension IF  13 .  
      The LAN IF  12  is connected with the LAN  1  as the need arises. The LAN IF  12  makes an interface operation relevant to the connected LAN  1 . The following operations are given as the interface operation. One is to convert voice packet given via the LAN  1  into a PCM signal, and another is to convert a PCM signal given via the TSW  11  into voice packet. Another is to monitor the state of the LAN, and another is to transmit various signals to networks connected via LAN. The LAN IF  12  further makes an exchange of various control informations relevant the foregoing interface operation with the control section  14  via the data highway  19  and the CPU bus  20 .  
      The extension IF  13  is connected with telephone terminals T 11  to T 1   j  as the need arises. The extension IF  13  makes an interface operation relevant to connected telephone terminals T 11  to T 1   j . The extension IF  13  further makes an exchange of various control informations relevant the foregoing interface operation with the control section  14  via the data highway  19  and the CPU bus  20 .  
      The control section  14  collectively controls the foregoing TSW  11 , LAN I/F  12 , and extension I/F  13  based on data stored in the storage section  15  to realize the operation as the main apparatus BT 1 .  
      The storage section  15  stores a table shown in  FIG. 3  prepared correspondingly to the main apparatuses BT 1  to BTn. The storage contents are known IP address, sub-IP address, priority of using self-IP address, priority of using IP address of another system, and information whether or not update information should be reflected.  
      The voice GW  16  makes connection and communication relevant to voice.  
      The timer  17  clocks current date and time.  
      The control section  14  of the first embodiment includes the following sections as a new function according to the present invention. One is a self-IP address access-message section  141  (hereinafter, referred to as access-message section  141 ). Another is an IP address acquire section  142  (hereinafter, referred to as acquire section  142 ). Another is a table update section  143  (hereinafter, referred to as update section  143 ).  
      If the self-IP address stored in the storage section  15  is added, changed or deleted, the access-message section  141  makes an access described below. The access-message section  141  makes access to other main apparatuses BT 2  to BTn based on their each IP address via the LAN  1 . Then, the access-message section  141  inserts the added, changed or deleted IP address into a control signal specified by QSIG protocol, for example, a facility information area determined by QSIG protocol, and thereafter, transmits it.  
      The acquire section  142  receives control signals sent from other main apparatuses BT 2  to BTn via the LAN  1 , and acquires each IP address inserted into the facility information area of the control signals.  
      When receiving the added, changed or deleted IP address from other main apparatuses BT 2  to BTn, the update section  143  adds, changes or deletes the corresponding IP address in the table stored in the storage section  15 .  
      The operation in the configuration described above will be explained below.  
       FIG. 4  is a view to explain the procedure of the transmitting/receiving operation when the connection from the main apparatus BT 1  to the main apparatus BT 2  is made.  FIG. 5  is a flowchart to explain the operation by the control section  14  of the main apparatus BT 1  when the connection to the main apparatus BT 2  is made.  
      A self-IP address of the table stored in the storage section  15  is updated (step ST 5   a ). In this case, the control section  14  of the main apparatus BT 1  makes an access to the main apparatus BT 2  using the highest priority IP address of the main apparatus BT 2  (step ST 5   b ). Thereafter, the control section  14  determines whether or not access is made within a preset time (step ST 5   c ). If the access is made within the preset time (Yes), the control section  14  inserts an update message and the updated self-IP address into a facility information area of a control signal, and transmits them to the main apparatus BT 2  (step ST 5   d ).  
      On the other hand, the foregoing time elapses; nevertheless, if access is not made (No), the control section  14  determines whether or not the next priority IP address is stored in the storage section  15  (step ST 5   e ). If the next priority IP address is stored in the storage section  15  (Yes), the control section  14  transfers to the step ST 5   b  to again make the connection to the main apparatus BT 2 . Then, the control section  14  repeats the procedures of steps ST 5   b  and ST 5   c  until the connection to the main apparatus BT 2  is made.  
      In step ST 5   e , if the next priority IP address is not stored in the storage section  15  (No), the control section stops the procedure, and thereafter, gives a message that no connection is made to the user of the main apparatus BT 1 .  
      Incidentally, the same procedure as described above is taken even if a new IP address is added or unnecessary IP address is deleted. The foregoing procedure is taken with respect to other main apparatuses BT 3  to BTn at different timing.  
       FIG. 6  is a flowchart to explain the operation by the control section  14  of the main apparatus BT 1  when a changed IP address arrives from the main apparatus BT 2 .  
      An updated IP address and a control signal including a message that update is made arrive from the main apparatus BT 2  (step ST 6   a ). In this case, the control section  14  extracts the IP address inserted into the facility information area of the control signal and the message that update is made. Thereafter, the control section  14  updates the corresponding IP address in the table stored in the storage section  15  based on the given message (step ST 6   b ).  
      Incidentally, the same procedure as described above is taken even if a newly added IP address or deleted IP address arrives. In addition, the same procedure is taken even if a message is given from other main apparatuses BT 3  to BTn.  
      According to the first embodiment, the storage section  15  of the main apparatus BT 1  previously registers the self-IP address and each IP address of other main apparatuses BT 2  to BTn. If the self-IP address is added, updated or deleted, the BT 1  transmits the added, updated or deleted self-IP address to other main apparatuses BT 2  to BTn.  
      Therefore, every when each IP address of other main apparatuses BT 2  to BTn is added, updated or deleted, the main apparatus BT 1  timely acquires the IP address, and automatically registers it in the storage section  15 . By doing so, it is possible to carry out IP address setup and registration resulting from a system change without spending much time and labor.  
      The user of the main apparatus BT 1  only registers each IP address of other main apparatuses BT 2  to BTn one time. Therefore, the operation required for the registration is largely simplified. In addition, there is no need of providing a server for collectively managing each IP address of main apparatuses BT 1  to BTn. Therefore, this serves to reduce a load to the LAN  1 ; as a result, the cost reduction is achieved in the entirety of the system.  
      According to the first embodiment, when making the connection to other main apparatuses BT 2  to BTn, the main apparatus BT 1  selects and uses several IP addresses previously stored in the storage section  15  in the order of high priority. Therefore, even if the high priority IP address is used in another main apparatus BT 3  or deleted, the main apparatus BT 1  uses the next high priority IP address to make the connection. By doing so, even if the connection request concentrates on the main apparatus BT 2  in the same time zone, relatively flexible measures against the concentration are taken.  
      According to the first embodiment, the main apparatus BT 1  gives a message of the updated IP address to other main apparatuses BT 2  to BTn using the facility information area of the already-existing control signal specified by QSIG protocol. Thus, there is no need of providing a dedicated signal line for giving a message of added, updated or deleted IP address. As a result, the configuration of the system is simplified.  
     Second Embodiment  
       FIG. 7  is a view to explain the procedure of the transmitting/receiving operation when the connection from the main apparatus BT 1  to the main apparatus BT 2  is made in a network telephone system according to a second embodiment of the present invention.  
      For example, when the main apparatus BT 1  boots, the control section  14  makes an access to the main apparatus BT 2  based on the IP address stored in the storage section  14 . Thereafter, the control section makes a query relevant to an added, updated or deleted IP address. In this case, the control section  14  inserts registered IP address and a query message into the facility information area of the control signal to be transmitted, and then, transmits them.  
      The main apparatus BT 2  analyzes the IP address included in the facility information area of the received control signal and the message. If there exists IP address other than the foregoing IP address, the main apparatus BT 2  gives a message that a new IP address exists to the main apparatus BT 1 .  
      Incidentally, the foregoing procedure may be taken according to the request from the user of the main apparatus BT 1  in addition to the boot thereof.  
      Thus, according to the second embodiment, the following effect is obtained. For example, the changed IP address is not received after given from other main apparatuses BT 2  to BTn in a time zone when the main apparatus BT 1  does not boot. In this case, address query is made with respect to these apparatuses BT 2  to BTn by the request of the user in the boot, and thereby, updated IP address is acquired.  
     Third Embodiment  
       FIG. 8  is a block diagram to explain the operation of updating an IP address for each group in a network telephone system according to a third embodiment of the present invention.  
      The LAN  1  is further connected with a gatekeeper GK. The gatekeeper GK includes a group management table, and has a group allocation control function relevant to main apparatuses BT 1  to BTn based on the group management table.  
      As seen from  FIG. 9 , the group management table stores data showing the corresponding relationship between several groups G 1 , G 2  and some main apparatuses belonging to these groups G 1 , G 2 . In this case, the main apparatuses BT 1  to BTn are divided into the groups G 1  and G 2 .  
      The operation of the system having the foregoing configuration will be described below.  
      For example, the IP address is updated in the main apparatus BT 1  shown in  FIG. 8 , and the updated IP address and a control signal including an update message are transmitted to the gatekeeper GK. The gatekeeper GK searches a group to which the main apparatus BT 1  belongs from the group management table to detect main apparatuses BT 2  and BT 3  belonging to the identical group. Based on the detection result, the gatekeeper transmits the control signal to the main apparatuses BT 2  and BT 3  so that they update the IP address of the main apparatus BT 1 .  
      According to the third embodiment, the gatekeeper GK is provided with the group management table showing the corresponding relationship between main apparatuses BT 1  to BTn and groups G 1 , G 2 . Thus, even if the update of IP address resulting from a system change is required, the update of IP address is concurrently controlled at the group unit.  
      For example, the number of the main apparatuses BT 1  to BTn increases resulting from a system expansion, and the LAN  1  is used in common to many main apparatuses BT 1  to BTn. Therefore, even if the environment described above is given, the update of IP address is concurrently controlled in the groups G 1  and G 2 . As a result, it is possible to update the IP address in a relatively short time, and thus, to reduce a load to the LAN  1  resulting from the change of IP address. This serves to effectively use the LAN  1  in accordance with the system scale.  
     Other Embodiments  
      The present invention is not limited to the foregoing embodiments. According to the first embodiment, if the updated IP address arrives from another main apparatus BT 2 , the corresponding IP address is automatically updated in the main apparatus BT 1 . The present invention is not limited to the first embodiment, and the following procedure may be taken if the updated IP address arrives from another main apparatus BT 2 . For example, a message that the IP address is updated is given to the user of the main apparatus BT 1 , and thereafter, the corresponding IP address is updated when the user inputs update instructions.  
      The update section  143  of the control section  14  may have two processing modes given below. One is a processing mode of automatically updating the corresponding IP address if updated IP address is received from another main apparatus. Another is a processing mode of automatically updating the corresponding IP address after the user inputs update instructions if updated IP address is received from another main apparatus. These modes may be selectively operated in accordance with the selection of the user. With the configuration, normally, the IP address is updated immediately every when the updated IP address is received. On the other hand, the IP address is updated in maintenance time only when the user determines that the update of the IP address is necessary. By doing so, the optimum update of IP address is carried out in accordance with various environments.  
      According to the third embodiment, the gatekeeper GK is provided with the group management table. However, if no gatekeeper GK is provided, at least one of the main apparatuses BT 1  to BTn may be provided with the gatekeeper GK.  
      Besides, various changes may be made within a range without diverging from the subject matter of the present invention. More specifically, various changes are possible in the configuration and kind of the system and the main apparatus, kind of telephone terminal, and updated IP address message and update control procedures.  
      Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as specified by the appended claims and their equivalents.