JP2011147159A - Telephone system and telephone terminal for the telephone system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily detect presence/absence of any type of terminal or master unit while attaining reduction of communication network load. <P>SOLUTION: According to embodiments, a telephone terminal connected through a communication network to a master unit, which performs communication between a plurality of telephone terminals registered in a terminal management table, is targeted and includes a timer, a transmission means and a detection means. The timer starts counting a predetermined time in timing to transmit a connection confirmation signal for confirming presence/absence of a connection with the master unit. After the lapse of the predetermined time, set for each terminal, as a time from transmission counted by the timer, the transmission means transmits the connection confirmation signal to the master unit. If a response signal to the transmission of the connection confirmation signal is redirected from the master unit, the detection means detects the presence of the master unit. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  Embodiments of the present invention relate to a telephone system that performs voice communication between telephone terminals via an IP network, such as an IP (Internet Protocol) telephone system, and a telephone terminal of the telephone system.

  2. Description of the Related Art In recent years, network telephone systems (IP telephone systems) that transmit and receive images and sounds as packet data in both directions via a packet network have begun to spread. In this IP telephone system, SIP (Session Initiation Protocol) is widely used as the protocol.

  In this type of system, the address of a terminal (hereinafter referred to as a SIP terminal) connected to the packet network is registered in advance in the main unit on the packet network, and the above registration is performed when a call is made between SIP terminals. The main device authenticates the SIP terminal based on the received address.

  By the way, even if a packet network failure occurs between the main device and the SIP terminal, a call is generated from the main device side or the SIP terminal side, or a re-registration request is periodically made before the registration valid period The connection state between the main device and the SIP terminal is not known. Normally, if a digital telephone or standard telephone connected to the main unit, or an IP terminal having a keep alive function, the main unit side can determine the connection status, so if there is an incoming call to that terminal, the service can be deployed. Is possible.

  However, in the case of a SIP terminal, the presence / absence status cannot be determined on the main device side. Therefore, in recent years, a method has been proposed in which a “Session Timer” related to Keep Alive is implemented in a SIP terminal according to the SIP terminal standard (for example, Patent Document 1).

Special table 2003-502945 gazette

  In the above method, the problem is solved by transmitting a re-INVITE or UPDATE message for the Session Timer between the SIP terminal and the main device. However, many SIP timers and main devices do not have the Session Timer installed. . Further, if these messages are transmitted to a large number of SIP terminals and main devices, the load on the packet network will increase.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a telephone system capable of reducing the load on a communication network and easily detecting the presence / absence of any type of terminal or main apparatus, and a telephone terminal of this telephone system. There is.

  According to the embodiment, the telephone terminal targets a telephone terminal connected via a communication network to a main apparatus that performs communication between a plurality of telephone terminals registered in the terminal management table, and includes a timer, a transmission unit, And detecting means. The timer measures a predetermined time from the transmission timing of a connection confirmation signal for confirming whether or not there is a connection with the main device. The transmission means transmits a connection confirmation signal to the main apparatus when a predetermined time set for each terminal has elapsed since the time of transmission counted by the timer. The detection means detects that the main device exists when a response signal to the connection confirmation signal is returned from the main device.

1 is a schematic configuration diagram showing a network telephone system according to a first embodiment. It is a block diagram which shows the function structure of the main apparatus in the 1st Embodiment. FIG. 3 is a diagram illustrating an example of storage contents of a system management table illustrated in FIG. 2. It is a figure which shows an example of the memory content of the terminal management table shown in FIG. FIG. 3 is a diagram showing an example of stored contents of a keep-alive counter maximum value shown in FIG. 2. FIG. 6 is a transmission sequence diagram of an OPTIONS message in the first embodiment. 4 is a flowchart showing a processing procedure of a main apparatus when an OPTIONS message is transmitted in the first embodiment. It is a non-response sequence diagram of the OPTIONS message in the first embodiment. 7 is a flowchart showing a processing procedure of the main apparatus when a response to the retransmitted OPTIONS message is returned in the first embodiment. 6 is a flowchart showing a processing procedure of the main apparatus when a response to a retransmitted OPTIONS message is not returned in the first embodiment. It is a block diagram which shows the function structure of a SIP terminal as 2nd Embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram showing a network telephone system according to the first embodiment.
This system has an IP network 1. A plurality of SIP terminals T1 to Ti (i is a natural number) and T21 to T2j (j is a natural number) using SIP are connected to the IP network 1. In addition, a main device BT and a gateway GW are connected to the IP network 1. The main apparatus BT has a function of assigning IP addresses to the SIP terminals T11 to T1i, T21 to T2j and a call control function to the SIP terminals T11 to T1i and T21 to T2j, and further each of the SIP terminals T11 to T1i, T21 to T21. It has a management function for the IP address assigned to T2j.

  The gateway GW connects the IP network 1 and the public network NW, and has a communication protocol and signal format conversion function between the IP network 1 and the public network NW.

FIG. 2 is a block diagram showing a functional configuration of the main apparatus BT according to the present invention.
The main apparatus BT includes a gateway interface (I / F) unit 11, an IP network interface (I / F) unit 12, a voice processing unit 13, a call control unit 14, a SIP control unit 15, and a storage unit 16. It has. The gateway interface unit 11, the IP network interface unit 12, the voice processing unit 13, the call control unit 14, the SIP control unit 15, and the storage unit 16 are connected to each other via a data highway 17.
The gateway interface unit 11, the IP network interface unit 12, and the voice processing unit 13 are connected to each other via the PCM highway 18.

  A gateway GW is connected to the gateway interface unit 11 as necessary. The gateway interface unit 11 performs interface processing between the connected gateway GW and the PCM highway 18. The gateway interface unit 11 exchanges various control information related to the interface processing with the call control unit 14 via the data highway 17.

  The IP network 1 is connected to the IP network interface unit 12 as necessary. The IP network interface unit 12 performs interface processing between the connected IP network 1 and the PCM highway 18. The IP network interface unit 12 exchanges various control information related to the interface processing with the call control unit 14 via the data highway 17.

The voice processing unit 13 has a function of converting voice packets received from the IP network 1 into voice signals that can be handled by the gateway GW and transmitting the voice signals to the gateway GW.
The call control unit 14 includes a CPU, a ROM, a RAM, and the like, and controls each unit of the main apparatus BT by software processing.

  The SIP control unit 15 executes a part of control processing executed by the call control unit 14, that is, control processing related to the SIP terminals T11 to T1i and T21 to T2j. The SIP control unit 15 is connected to a keep alive timer 19g.

  The storage unit 16 stores routing information necessary for connection control of the call control unit 14, and further stores a system management table 161, a terminal management table 162, and a keep-alive counter maximum value 163. Among these, the system management table 161 stores, for example, as shown in FIG. 3, a keep alive activation flag, a keep alive activation counter, and keep alive timer management information.

  For example, as shown in FIG. 4, the terminal management table 162 includes terminal registration information, terminal timer management information, a terminal call state, a terminal keep alive counter, and a terminal keep for each of the SIP terminals T11 to T1i and T21 to T2j. The alive state is stored.

  The keep-alive counter maximum value 163 stores data as shown in FIG. 5, for example.

On the other hand, the SIP control unit 15 includes an OPTIONS communication unit 151 and a presence / absence determination unit 152.
The OPTIONS communication unit 151 transmits a capability inquiry message (OPTIONS message) as a keep alive message at a transmission time interval set in the timer 19 at different transmission timings stored in the terminal management table 162 at the SIP terminal T11 on the IP network 1. To T1i, T21 to T2j, and response messages (200 OK) from the SIP terminals T11 to T1i and T21 to T2j for the OPTIONS message are received. An error message other than 200 OK may be used, and any response is required.

  The presence / absence determination unit 152 monitors whether the 200 OK message is returned from the SIP terminals T11 to T1i and T21 to T2j in response to the transmission of the OPTIONS message, so that the SIP terminals T11 to T1i and T21 to T2j It determines whether or not it exists, and notifies the call control unit 14 of the determination result. Further, after the OPTIONS message is transmitted, when the 200 OK message is not returned and the timer 19 counts the maximum value of the keep alive counter, the OPTIONS communication unit does not send back the OPTIONS message to the SIP terminal T12 again. 151 is instructed.

Next, the processing operation in the above configuration will be described.
For example, as shown in FIG. 6, when the main apparatus BT receives a registration request “REGISTER” message from the SIP terminal T11, for example, it registers and sets necessary registration information TR in the terminal management table 162, and sends a response “200 OK” to the SIP terminal T11. Return to

  In addition, the SIP control unit 15 of the main apparatus BT notifies the call control unit 14 of the terminal presence as “terminal presence”. At this time, the presence / absence is determined based on the keep-alive timer activation flag SF stored in the system management table 161, and when it is not activated, the timer 19 is activated according to the keep-alive timer management information ST. At this time, necessary timer management information is registered and set in the terminal management table 162 in association with the SIP terminal T11. If the timer 19 has already been started, it continues.

  Next, the SIP control unit 15 acquires the system keep alive counter SC from the system management table 161 and sets it in the terminal keep alive counter TC of the SIP terminal T 11 in the terminal management table 162. Since the keep alive counter TC sets the system keep alive counter SC that is sequentially updated, the timing at which the keep alive counter TC becomes the same value as the maximum value of the keep alive counter (TCMAX) is different for each terminal. Thereby, the timing for transmitting the OPTIONS message differs for each terminal and is distributed.

  When the timer 19 times out, the SIP control unit 15 executes the processing procedure shown in FIG. First, the SIP control unit 15 determines whether or not the SIP terminal T11 has been registered (step ST7a). If it has been registered, the SIP control unit 15 subsequently determines whether or not to wait for an OPTIONS response (step ST7b). ).

  Here, when waiting for OPTIONS transmission, the SIP control unit 15 determines whether or not the call state TS of the SIP terminal T11 is empty (step ST7c), and if it is empty, the terminal keep counter TC is kept. It is determined whether or not the alive counter maximum value TCMAX is exceeded (step ST7d).

  Here, when the terminal keep counter TC is the same as the keep alive counter maximum value TCMAX, the SIP control unit 15 transmits an OPTIONS message to the SIP terminal T11 (step ST7e), and the terminal keep alive counter in the terminal management table 162 is received. The TC is reset, and the terminal keep alive state TKS is updated to “OPTIONS response wait” (step ST7f).

  On the other hand, if the terminal keep counter TC does not exceed the keep alive counter maximum value TCMAX in step ST7d, the SIP control unit 15 determines the terminal keep alive counter TC in the terminal management table 162 and the system keep in the system management table 161. The alive counter SC is updated (+1) (step ST7g). In step ST7h, when the system keep alive counter SC becomes the same as the keep alive counter maximum value TCMAX, the system keep alive counter SC is reset (step ST7i).

  If the SIP terminal T11 waits for an OPTIONS response in step ST7b or if the SIP terminal T11 is busy in step ST7c, the SIP control unit 15 proceeds to the process in step ST7g.

  Thereafter, if no response is returned from the SIP terminal T11, the SIP control unit 15 sets the terminal timer management information TT in the terminal management table 162 according to the SIP protocol as shown in FIG. 8, and retransmits the OPTIONS message. I do. This retransmission process follows the SIP standard protocol.

  In FIG. 9, when the SIP control unit 15 returns any response (normal, error) of the OPTIONS message from the SIP terminal T11 (step ST9a), the SIP control unit 15 determines that “terminal exists”, and then continues. Then, it is determined whether or not the terminal keep alive state TKS in the terminal management table 162 is “waiting for OPTION response” (step ST9b).

  Here, when it is “waiting for OPTION response” (Yes), the SIP control unit 15 updates the terminal keep alive state TKS in the terminal management table 162 to “waiting for OPTIONS transmission” (step ST9c). On the other hand, when it is “waiting for OPTION transmission” (No), the SIP control unit 15 notifies the SIP terminal T11 of an error message (step ST9d).

  Further, during the retransmission process, the SIP control unit 15 executes the processing procedure shown in FIG. 10 and determines whether or not the final timeout has occurred each time the timer 19 times out (step ST10b). Here, when there is no response from the SIP terminal T11 and the final timeout occurs (Yes), the SIP control unit 15 deletes the terminal registration information TR corresponding to the SIP terminal T11 in the terminal management table 162, and the call control unit 14 Is notified of the terminal absence (step ST10c).

  On the other hand, if the final timeout has not been reached (No), the SIP control unit 15 transmits an OPTIONS message to the SIP terminal T11 to update the terminal keep alive state TKS in the terminal management table 162 to “wait for OPTIONS response”. The retransmission timer is set and the retransmission counter is updated (step ST10d).

  As described above, in the first embodiment, the main device BT transmits the OPTIONS message defined by the SIP protocol to the SIP terminals T11 to T1i and T21 to T2j at different timings for each terminal. By receiving the responses from T1i and T21 to T2j, detection processing for the presence / absence of SIP terminals T11 to T1i and T21 to T2j having no Session Timer is executed.

  Therefore, without occupying the IP network 1 for the transmission of the OPTIONS message, and without the response signals from the SIP terminals T11 to T1i and T21 to T2j being concentrated in the same time zone, any type of SIP terminals T11 to T1i can be obtained. , T21 to T2j can be detected efficiently.

  In the first embodiment, when a response signal to the transmission of the OPTIONS message is not returned from the corresponding SIP terminal T11, the OPTIONS message is transmitted again to the SIP terminal T11 after the predetermined time is counted by the timer 19. Therefore, even if the response signal to the OPTIONS message cannot be returned on the SIP terminal T11 side due to a temporary failure, the presence of the SIP terminal T11 can be detected by the main device BT. Can increase the sex.

  In the first embodiment, when the main device BT resends the OPTIONS message and the timer 19 reaches the final timeout, if the response is not returned from the corresponding SIP terminal T12, the SIP terminal T12 is immediately It can be determined that it does not exist.

  Furthermore, in the first embodiment, since the SIP control unit 15 of the main apparatus BT transmits the OPTIONS message only to, for example, the SIP terminals T11 and T14 to T1i determined to be free, the IP network 1 can be prevented, and the load on the IP network 1 can be further reduced.

(Second Embodiment)
FIG. 11 is a block diagram showing a functional configuration of the plurality of SIP terminals T11 to T1i and T21 to T2j as the second embodiment. Here, the SIP terminal T11 will be described as a representative.
The SIP terminal T11 includes an IP network interface (I / F) unit 21, a voice packet processing unit 22, a voice input / output interface (I / F) unit 23, a control unit 24, an operation panel 25, and a storage unit 26. And a display unit 27.

  The IP network interface unit 21 performs an interface operation related to the IP network 1. In other words, the IP network interface unit 21 extracts voice packets and control data from transmission packets sent from the IP network 1, and provides the voice packets to the voice packet processing unit 22 and the control data to the control unit 24. The IP network interface unit 21 transmits the voice packet given from the voice packet processing unit 22 and the data given from the control unit 24 to the IP network 1.

  The voice packet processing unit 22 converts the voice packet given from the IP network interface unit 21 into an analog received voice signal and gives it to the voice input / output interface unit 23. The voice packet processing unit 22 converts the transmission voice signal input from the voice input / output interface unit 23 into a voice packet that can be handled by the IP network 1, and provides the voice packet to the IP network interface unit 21.

  A microphone 28 and a speaker 29 are connected to the voice input / output interface unit 23. The voice input / output interface unit 23 inputs the transmission voice signal input from the microphone 28 to the voice packet processing unit 22, and outputs the received voice signal output from the voice packet processing unit 22 from the speaker 29.

  The control unit 24 controls each unit of the SIP terminal T11 and performs communication processing with the IP network 1 by software processing.

  The operation panel 25 has a key switch and accepts various instruction inputs to the control unit 24 by the user. The display unit 27 includes an LCD or the like, and performs various types of information notification to the user.

  The storage unit 26 stores the system management table, main device management table, and maximum keep-alive counter value described in the first embodiment.

  Incidentally, the control unit 24 includes an OPTIONS communication unit 241 and a presence / absence determination unit 242. The OPTIONS communication unit 241 transmits an OPTIONS message as a keep alive message to the main device BT on the IP network 1 at a transmission time interval set in the timer 30, and a response message (200 OK) from the main device BT to this OPTIONS message. Is to be received. Note that the transmission timing of the OPTIONS message differs between the SIP terminals T11 to T1i and T21 to T2j.

  The presence / absence determination unit 242 determines whether or not the main device BT exists by monitoring whether or not a 200 OK message is returned from the main device BT in response to the transmission of the OPTIONS message. Further, after the OPTIONS message is transmitted, when the response message is not returned from the main apparatus BT and the timer 30 counts the maximum keep alive counter value, the OPTIONS communication unit 241 is configured to transmit the OPTIONS message again to the main apparatus BT. To instruct. Further, when the timer 30 times out a predetermined timeout, the presence / absence determination unit 242 determines that the main device BT does not exist, and displays the determination result on the display unit 27.

  As described above, in the second embodiment, in each of the SIP terminals T11 to T1i and T21 to T2j, the presence / absence determination process of the main device BT based on the OPTIONS message is different for each terminal. Therefore, the main device BT and each of the SIP terminals T11 to T1i and T21 to T2j cooperate with each other without causing only the main device BT to perform the presence / absence determination processing. Thus, the reliability in detecting the presence / absence of the main device BT and SIP terminals T11 to T1i and T21 to T2j connected to the IP network 1 can be further improved. Moreover, the main apparatus BT and each SIP terminal T11-T1i, T21-T2j cooperate, and the said determination process can reduce the processing load of the main apparatus BT.

(Other embodiments)
The present invention is not limited to the above embodiments. For example, in each of the above-described embodiments, the example in which the OPTIONS message is used to determine the presence / absence of the SIP terminal or the main apparatus has been described. However, the present invention is not limited to this. For example, a re-INVIE or UPDATE message for Session Timer may be used.

  In addition, the configuration and type of the system, the configuration and type of the main device, the configuration and type of the SIP terminal, the transmission / reception procedure of the OPTIONS message, the presence / absence determination processing procedure, etc. It can be implemented with deformation.

  DESCRIPTION OF SYMBOLS 1 ... IP network, 11 ... Gateway interface part, 12 ... IP network interface part, 13 ... Voice processing part, 14 ... Call control part, 15 ... SIP control part, 16 ... Memory | storage part, 17 ... Data highway, 18 ... PCM highway , 19, 30 ... timer, 151, 241 ... OPTIONS communication unit, 152, 242 ... existence / non-existence determination unit, 161 ... system management table, 162 ... terminal management table, 163 ... maximum keep-alive counter, 21 ... IP network Interface unit, 22 ... Voice packet processing unit, 23 ... Voice input / output interface unit, 24 ... Control unit, 25 ... Operation panel, 26 ... Storage unit, 27 ... Display unit, 28 ... Microphone, 29 ... Speaker, BT ... Main device , T11 to T1i, T21 to T2j ... SIP terminals, GW ... gateway, NW ... public network.

Claims (6)

A telephone terminal connected via a communication network to a main apparatus that performs communication between a plurality of telephone terminals registered in the terminal management table,
A timer for measuring a predetermined time from the transmission timing of a connection confirmation signal for confirming the presence or absence of connection with the main device;
Transmitting means for transmitting the connection confirmation signal to the main device when a predetermined time set for each terminal has elapsed since the time of transmission counted by the timer;
A telephone terminal of a telephone system comprising detection means for detecting the presence of the main device when a response signal to the connection confirmation signal is returned from the main device.   The telephone according to claim 1, wherein the detection means causes the transmission means to send the connection confirmation signal to the main device again after a predetermined time is counted by the timer when a response signal to the connection confirmation signal is not returned. System phone terminal.   3. The detection unit according to claim 2, wherein when the response signal is not returned from the main unit within a predetermined time from the retransmission timing of the connection confirmation signal, the detection unit detects that the main unit does not exist. Telephone terminal of the telephone system. A telephone comprising a plurality of telephone terminals connected to a communication network, and a main apparatus for connecting the plurality of telephone terminals via the communication network and communicating between the plurality of telephone terminals registered in the terminal management table A system,
A timer that is provided in the telephone terminal and counts a predetermined time from the transmission timing of a connection confirmation signal for confirming the presence or absence of connection with the main device;
Transmitting means for transmitting the connection confirmation signal to the main apparatus when a predetermined time set for each terminal has elapsed since the transmission time provided in the telephone terminal and counted by the timer;
A telephone system, comprising: a detecting unit provided in the telephone terminal and detecting that the main apparatus is present when a response signal to the connection confirmation signal is returned from the main apparatus.   The detection means causes the transmission means to send the connection confirmation signal to the main apparatus again after a predetermined time is counted by the timer when a response signal to the connection confirmation signal is not returned from the main apparatus. 4. The telephone system according to 4.   6. The detection unit according to claim 5, wherein when the response signal is not returned from the main unit within a predetermined time from the retransmission timing of the connection confirmation signal, the detection unit detects that the main unit does not exist. Phone system.

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