JP4576796B2 - Call control method in VoIP communication apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a call control method in a VoIP communication apparatus that performs voice communication in a VoIP (Voice over Internet Protocol) network, and relates to a call control method in a VoIP communication apparatus suitable for application to, for example, a gateway apparatus and a terminal apparatus. Is.
[0002]
[Prior art]
In recent years, research and development of a VoIP (Voice over Internet Protocol) system that performs voice communication using IP packets has been promoted, and a telephone voice call can be performed using the Internet. The Internet Engineering Task Force (IETF) of the Internet Society (ISOC) conducts standardization processing related to the Internet, discusses standardization proposals related to the Internet, etc. (RFC: Request for Comments) is created.
[0003]
RFCs are also issued for non-standard procedures. As information related to VoIP, for example, RFC-2705 describes Media Gateway Control Protocol (MGCP) Version 1.0.
[0004]
In a VoIP network system in which a VoIP communication device based on this MGCP is connected to an IP network, for example, a call agent (Call Agent) that handles translation and routing of telephone numbers and IP addresses, and line control and voice packetization and A voice communication service is provided by a gateway that handles non-packetization.
[0005]
The call agent manages voice encoding capability in gateways in the IP network, manages correspondence between telephone numbers and IP (Internet Protocol) addresses, and controls communication between gateways. The call agent generates commands for connection, call establishment, change, and disconnection, and notifies the gateway.
[0006]
Referring to FIG. 5, there is shown an operation procedure at the time of call connection when voice communication is performed by such a VoIP device using MGCP. The VoIP device 54 in which the gateway 50 and the telephone terminal 52 are accommodated performs an operation related to call control in accordance with an instruction from the call agent 56 connected via the IP network.
[0007]
Specifically, when detecting the off-hook operation of the telephone terminal 52, the gateway 50 notifies the event to the call agent 56 with an NTFY message, and the call agent 56 returns a response Ack to the message to the gateway 50. Thereafter, the call agent 56 instructs the gateway 50 to send a dial tone and receive a destination telephone number by using an RQNT / CRCX command. The gateway 50 returns a response Ack to the command to the call agent 56, and the gateway 50 sends a dial tone to the telephone terminal 52 accommodated in accordance with the instruction from the call agent 56, and sends it from the telephone terminal 52. Start receiving the destination telephone number.
[0008]
[Non-Patent Document 1]
Arango, et al., The Internet Engineering Task Force: Request For Comments: 2705; Category: Informational.
[Non-Patent Document 2]
Jonathan Davidson / James Peters, edited by Kazesha, supervised by Cisco Systems, "VoIP Basic Guide", first edition, SOFTBANK PUBLISHING CORPORATION, January 18, 2001, p.302 -312.
[0009]
[Problems to be solved by the invention]
However, if any failure occurs in the IP network, message communication between the VoIP device 54 and the call agent 56 cannot be performed. For example, when a failure occurs in the call agent 56, the NTFY message that should be received by the call agent 56 when the telephone terminal 52 goes off-hook is not received, and the RQNT / CRCX command is sent from the call agent 56 to the VoIP device 54. If no message is sent, a dial tone is not generated, and the handset of the telephone terminal 52 on the caller side that has performed the off-hook operation is silent. At the time of the failure on the call agent 56 side, the caller immediately after the off-hook operation has a useless concern that the telephone terminal 52 may have failed.
[0010]
In addition, if the RQNT / CRCX command is delayed and the dial tone transmission to the phone terminal 52 is delayed, the caller who performed the off-hook operation inputs the callee number to the phone terminal 52 until the dial tone is heard. There was a problem that a sense of incongruity occurred.
[0011]
The present invention eliminates such disadvantages of the prior art, avoids silence during off-hook when making a call even if a failure occurs in the call agent, IP network, etc. Another object of the present invention is to provide a call control method in a VoIP communication apparatus that can be operated without a sense of incongruity and has a good feeling of operation.
[0012]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a call control method in a VoIP communication apparatus that performs communication in accordance with the media gateway control protocol. This method detects an off-hook of a telephone terminal and detects the off-hook. Then, a message indicating off-hook is notified to the call agent, and even if a command from the call agent is not notified, a dial tone is autonomously sent to the telephone terminal in response to detection of the off-hook, and the telephone terminal Reception of a destination telephone number is started, and when a command from a call agent is received, the destination telephone number is notified to the call agent according to the command.
[0013]
In this case, even if a response from the call agent cannot be detected within a predetermined time, a dial tone is sent to the telephone terminal in response to the detection of off-hook, and reception of the destination telephone number from the telephone terminal is started. Good. Further, when a response from the call agent is not detected within a predetermined time, a communication interruption may be detected and a tone corresponding to the communication interruption may be transmitted to the telephone terminal.
[0014]
Even when a command from the call agent is not detected within a predetermined time, it is preferable to transmit a dial tone and receive a destination telephone number. When a command from the call agent is not detected within a predetermined time, a communication interruption may be detected and a tone corresponding to the communication interruption may be transmitted to the telephone terminal.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a call control method in a VoIP communication apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
[0016]
Referring to FIG. 2, an outline of a VoIP system 16 in which a call agent 12 and a plurality of VoIP (Voice over Internet Protocol) devices 14 are connected to an IP network 10 is illustrated. The VoIP device 14 of this embodiment includes a gateway 20 connected to the IP network 10 and a telephone terminal 22 accommodated in the gateway 20, and when the telephone terminal 22 goes off-hook, the media gateway control protocol (MGCP) : Call connection control is performed according to an instruction from the call agent 12 according to the Media Gateway Control Protocol.
[0017]
Specifically, FIG. 1 shows an operation procedure in a normal time when no failure or network congestion occurs in the IP network 10 and the call agent 12. When the gateway 20 detects that the telephone terminal 22 is off-hook, an event occurs. The gateway 20 sends an NTFY message to the call agent 12, and generates a dial tone spontaneously triggered by the off-hook detection. The telephone number is sent to the telephone terminal 22 and reception of the destination number from the telephone terminal 22 is started. At the same time, the gateway 20 starts a monitoring timer for monitoring responses and commands. In other words, the gateway 20 at this point does not require the reception of the response Ack and the RQNT / CRCX command, and automatically dials the dial tone before receiving the response and the notification from the call agent 12 using the off-hook detection as a trigger. Send to terminal 22. In the monitoring timer, two time limits are set, ie, a response monitoring time for monitoring the response Ack and a command monitoring time for monitoring command reception, and each time-out is monitored. The command monitoring time is set to a time during which it is possible to detect that a network failure has occurred. For example, the command monitoring time is set to several seconds to several tens of seconds.
[0018]
Next, the call agent 12 in which no failure has occurred sends a response Ack to the NTFY message to the gateway 20, and then sends a RQNT / CRCX command to the gateway 20. The gateway 20 can recognize that the NTFY message has arrived at the call agent 12 by receiving the response Ack.
[0019]
In addition, when the RQNT / CRCX command from the call agent 12 is received by the gateway 20 in the state where the destination number is not input to the telephone terminal 22, the dial tone is transmitted to the telephone terminal 22 according to the command. In this embodiment, the dial tone is continuously transmitted to the telephone terminal 22.
[0020]
In the example shown in the figure, the response Ack is received within the response monitoring setting time of the monitoring timer, and the RQNT / CRCX command is notified to the gateway 20 within the monitoring time command monitoring setting time. The call agent is notified to the gateway 20 of a transmission instruction (S: dl) and a reception destination telephone number reception instruction (r: D / 0-9 # * T).
[0021]
When the caller starts dial input, the gateway 20 stops sending the dial tone and stores the callee number. If the RQNT / CRCX command is notified to the gateway 20 during this dial input, reception of the destination telephone number has started, so no new dial tone is sent and reception of the destination telephone number continues. At the same time, a command response Ack is returned to the call agent 12. When input of the destination number is completed, the destination telephone number including the numbers entered before and after receiving the command from the call agent 12 is sent to the call agent 12 instructed to receive the destination telephone number. Can do.
[0022]
Referring to FIG. 3, this figure shows a state where the call agent 12 does not receive the NTFY message sent from the gateway 20 due to some failure in the call agent 12 or network congestion. . In this case, since a response Ack for the NTFY message is not generated and sent to the gateway 20, a response waiting timeout occurs when the response monitoring time elapses. A dial tone is autonomously sent to the telephone terminal 22 after the off-hook is detected from the gateway 20 to the telephone terminal 22, but when the monitoring timer times out, the gateway 20 sends a busy tone (BUSY to the telephone terminal 22). ) Or Rioder Tone (REORDER) and sending it to notify the caller of the failure on the IP network 10 side. When the input of the destination number is started and the number input is being accepted, the gateway 20 that has detected the time-out transmits a busy tone (BUSY) or a rioder tone (REORDER) to the telephone terminal 22.
[0023]
In the example shown in FIG. 4, the response Ack to the NTFY message is notified from the call agent 12 to the gateway 20, but after that some trouble or congestion occurs in the IP network or the call agent 12, the RQNT / CRCX command is received within a certain time. Is not notified to the gateway 20. For this reason, when the command monitoring time (for example, 20 seconds) elapses in the gateway 20, a command waiting timeout occurs. In this case, the gateway 20 recognizes the interruption of communication with the call agent 12 by detecting this timeout, and sends a busy tone (BUSY) or a rioder tone (REORDER) to the telephone terminal 22 to transmit the occurrence of a failure on the IP network side. The person in charge. Similarly to the example shown in FIG. 3, the gateway 20 that has detected a timeout sends a busy tone (BUSY) or a rioder tone (REORDER) to the telephone terminal 22 even when there is no sound while the destination number is being input.
[0024]
As described above, the VoIP device 14 connected to the IP network 10 basically has a function of performing a call control operation according to the media gateway control protocol (MGCP). Even if a failure occurs on the IP network side, etc., and the response and command from the call agent 12 cannot be detected by the VoIP device 14, a dial tone is sent to the calling operator side, and the destination telephone Since the reception of the number is started, it is possible to prevent anxiety about failure of the VoIP device 14 such as a telephone terminal when off-hooking when making a call, and it is possible to operate without a sense of incongruity and to improve the operational feeling. Further, even when a packet delay occurs on the network side, the operability is improved because the destination number can be input without waiting for a command from the call agent.
[0025]
【The invention's effect】
As described above, according to the present invention, when a call control operation is performed according to the Media Gateway Control Protocol (MGCP), a failure or congestion occurs in the call agent or the IP network, and a response and a command from the call agent are received. Even if it cannot be detected, a dial tone can be sent to the call operator and reception of the callee telephone number can be started. Therefore, it is possible to avoid silence during off-hook when making a phone call, prevent anxiety about a VoIP communication device such as a telephone terminal, and operate without a sense of incongruity. Even if a packet delay occurs on the network side, the operability is improved because the caller ID can be input without waiting for a command from the call agent.
[Brief description of the drawings]
FIG. 1 is a diagram showing a normal operation procedure of a VoIP system to which the present invention is applied.
FIG. 2 is a block diagram showing a configuration example of a VoIP system to which the present invention is applied.
FIG. 3 is a diagram illustrating an operation example when a failure occurs in the VoIP system.
FIG. 4 is a diagram illustrating an operation example when a failure occurs in the VoIP system.
FIG. 5 is a diagram showing a conventional example of a call connection procedure using a media gateway control protocol (MGCP).
[Explanation of symbols]
12 Call agent
14 Voice over Internet Protocol (VoIP) equipment
20 gateway
22 Telephone terminal

Claims (4)

In a call control method in a VoIP (Voice over Internet Protocol) communication apparatus including a gateway connected to at least an IP (Internet Protocol) network, the method includes:
Detecting off-hook of the phone terminal at the gateway ,
When the off-hook is detected, an off-hook detection message indicating the off-hook is notified to the call agent connected to the IP network , and the RQNT / CRCX command in the media gateway control protocol is not notified from the call agent. However, in response to the detection of the off-hook, a dial tone is autonomously transmitted to the telephone terminal,
Start receiving the destination telephone number from the telephone terminal,
If the response to the off-hook detection message from the call agent or the RQNT / CRCX command from the call agent is not detected within a predetermined time, a communication interruption is detected and a tone corresponding to the communication interruption is sent to the telephone terminal. A call control method in a VoIP communication device, characterized by being transmitted. The method of claim 1, wherein the method comprises:
When RQNT / CRCX command from the call agent is received, the called number and notifies the call agent in accordance with the RQNT / CRCX command,
When a response to the off-hook detection message or the RQNT / CRCX command from the call agent is not detected within a predetermined time, a communication interruption is detected and a tone corresponding to the communication interruption is transmitted to the telephone terminal. Call control method in VoIP communication equipment. In a VoIP (Voice over Internet Protocol) communication device including a gateway connected to at least an IP (Internet Protocol) network, the device includes:
Means for detecting off-hook of a telephone terminal at the gateway;
When the off-hook is detected, an off-hook detection message indicating the off-hook is notified to the call agent connected to the IP network, and the RQNT / CRCX command in the media gateway control protocol is not notified from the call agent. And means for autonomously sending a dial tone to the telephone terminal in response to the detection of the off-hook,
Means for starting reception of a destination telephone number from the telephone terminal;
If the response to the off-hook detection message from the call agent or the RQNT / CRCX command from the call agent is not detected within a predetermined time, a communication interruption is detected and a tone corresponding to the communication interruption is sent to the telephone terminal. A VoIP communication apparatus comprising: means for sending out. 4. The device of claim 3, wherein the device is
When RQNT / CRCX command from the call agent is received, and means for notifying a called number to the call agent in accordance with the RQNT / CRCX command,
Means for detecting a communication interruption if the response to the off-hook detection message or the RQNT / CRCX command is not detected within a predetermined time, and sending a tone corresponding to the communication interruption to the telephone terminal. VoIP communication equipment.

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