JP3874641B2 - Relay device, its control program, and communication method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a relay device that performs call control and RTP (Real-time Transport Protocol) control, a control program thereof, and a communication method.
[0002]
[Prior art]
The HTC of the TTC standard. As shown in FIG. 4, in a relay device compliant with the H.323 standard, when an on-hook signal is received from a telephone connected to this relay device during RTP communication, a release complete message is sent to the relay device of the communication destination. Send. When receiving the release complete message, the relay device of the communication destination outputs a busy tone signal to a telephone connected to the release complete message.
[0003]
[Problems to be solved by the invention]
However, in the prior art, when a failure such as power-off of the relay device or network device on the communication destination side occurs during call connection, as described above, there is no communication unless it is disconnected by on-hook operation by the caller. Therefore, there is a problem that the state where the call is held out continues.
[0004]
The present invention pays attention to such a conventional problem, and avoids holding up a call even if a failure such as a power-off of a relay device or a network device on the communication destination side occurs during call connection. It is an object of the present invention to provide a relay device that can perform communication, a control program thereof, and a communication method.
[0005]
[Means for Solving the Problems]
The relay device for achieving the object is
In a relay device that performs call control and RTP (Real-time Transport Protocol) control,
A reception status detecting means for detecting whether or not an RTP packet is not received for a predetermined time or more during communication by the RTP control;
When the reception status detection means detects that the RTP packet has not been received for the predetermined time or more, a communication disconnection processing means for executing a communication disconnection process with the counterpart device ;
Silence compression processing detecting means for examining a message based on the call control protocol when communicating with the counterpart device and detecting whether or not the communication based on the RTP control has been silence-compressed. ,
Even if the communication disconnection processing unit detects that the RTP packet has not been received for the predetermined time or longer by the reception status detection unit, the silence compression processing detection unit detects the silence compression processing. When it is detected that the communication is performed, the communication disconnection process with the counterpart device is not executed .
[0006]
Here, in the communication disconnection process by the relay device, a busy tone signal may be output to the communication source side, or a release complete message may be output to the communication destination side.
[0007]
Further, the predetermined time may be a time exceeding a maximum multiplex processing time of the RTP packet. Further, a multiprocessing time recognizing means for recognizing a multiprocessing time of the RTP packet in the communication at the start of communication by the RTP control, and the predetermined multi-processing time recognized by the multiprocessing time recognizing means. Judgment time setting means for setting the time may be provided.
[0009]
Here, each of the above relay devices may be incorporated in the telephone.
[0010]
In addition, the control program of the relay device for achieving the above-mentioned object is
In a control program for a relay device that performs call control and RTP (Real-time Transport Protocol) control,
A silence compression processing detection step of examining a message according to the call control protocol when communicating with the counterpart device and detecting whether or not the communication by the RTP control has been subjected to silence compression processing;
A reception state detecting step of detecting whether or not an RTP packet has not been received for a predetermined time or more during communication by the RTP control;
It is a case where it is detected in the reception status detection step that the RTP packet has not been received for the predetermined time or longer, and communication by the RTP control is performed in the silence compression processing detection step. Communication disconnection processing step for executing communication disconnection processing when it is detected that it has not been subjected to,
Is executed by an arithmetic processing unit .
[0011]
In addition, a communication method for achieving the above object is as follows:
In a communication method for performing call control and RTP (Real-time Transport Protocol) control,
A silence compression processing detection step of examining a message according to the call control protocol when communicating with the counterpart device and detecting whether or not the communication by the RTP control has been subjected to silence compression processing;
A reception state detecting step of detecting whether or not an RTP packet has not been received for a predetermined time or more during communication by the RTP control;
It is a case where it is detected in the reception status detection step that the RTP packet has not been received for the predetermined time or longer, and communication by the RTP control is performed in the silence compression processing detection step. Communication disconnection processing step for executing communication disconnection processing when it is detected that it has not been subjected to,
It is characterized by having.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a communication system according to the present invention will be described with reference to the drawings.
[0013]
As shown in FIGS. 1 and 2, the communication system according to the present embodiment includes a relay device 10 connected to the LAN line 2 and a telephone 1 connected to the relay device 10.
[0014]
The relay apparatus 10 includes an FXS interface 12 and an Ethernet (registered trademark of Xerox Corporation) interface 11. The FXS interface 12 is equipped with a VoIP (Voice over Internet Protocol) gateway, to which the telephone 1 is connected. The Ethernet interface 11 is connected to the LAN line 2 described above. At the end of the LAN line 2, the relay device 10 and the telephone 1 on the communication destination side are connected via a network device or the like. The network device may basically be a router, and a WAN (wide area network) may be connected to the end of the router. In this embodiment, it is assumed that the HUB 3 is connected for the sake of simplicity of explanation.
[0015]
As shown in FIG. 2, the relay device 10 includes the Ethernet interface 11 connected to the LAN line 2 on the communication destination side, the FXS interface 12 connected to the telephone 1 on the communication source side, A reception buffer 13 for temporarily storing received data input to the Ethernet interface 11, a data memory 14 for storing various control programs, various data, and the like, and a CPU 15 that operates according to a program stored in the data memory 14. And a DSP (Digital Signal Processor) 16 that performs digital signal processing such as decoding processing of received data. In FIG. 2, the flow of received data is indicated by thick solid arrows.
[0016]
The control program 14a stored in the data memory 14 is a TTC standard H.264 standard. H.323, which is a call control protocol compliant with the H.323 standard. 255Q931 and the capability information exchange protocol H.264. 245, RTP, a self-cutting program that is a characteristic part of the present invention, and the like are installed. In addition, the control program for the gatekeeper and the terminal is H.264. A 225RAS may be mounted and a gatekeeper may be provided. Also, the DSP 16 has a G.G. 729 is mounted.
[0017]
The configuration information setting data 14b stored in the data memory 14 includes a LAN line IP address, a subnet mask, a no-communication timeout time (determination time) described later, and the like.
[0018]
In the present embodiment, the reception status detection unit includes a data memory 14 in which a no-communication timeout period and a control program are stored, and a CPU 15 that executes the control program. The communication disconnection processing unit, the data memory 14, the CPU 15, and a DSP 16 that outputs a busy tone signal in response to an instruction from the CPU 15 are provided.
[0019]
Next, H. which is a call control protocol. The sequence at the time of outgoing connection by 255Q931 will be described with reference to FIG. In the figure, the left side indicates the calling side, and the right side indicates the receiving side.
[0020]
When the calling side relay device receives a dial from the calling side telephone, the IP address corresponding to the dial is checked, and a setup message is transmitted to the called side relay device in which this IP address is set.
[0021]
Upon receiving the setup message, the receiving side relay device outputs a call signal to the receiving side telephone and transmits an alert message to the calling side relay device. When the alerting message is received, the originating relay device outputs a call waiting signal to the originating telephone. Thereafter, when the receiving-side relay device receives an off-hook signal from the receiving-side telephone, it transmits a connect message to the calling-side relay device. As a result, the media channel is opened, RTP communication between the relay devices is established, and a telephone call between the telephones becomes possible. Here, the media channel is opened by reception of the connect message, but may be performed by reception of the alert message. In addition, when receiving the setup message, the relay device on the called side may transmit a call proceeding message before transmitting the alert message.
[0022]
Next, H.I. The sequence at the time of cutting | disconnection by 255Q931 is demonstrated using FIG.
[0023]
As explained in the prior art, during RTP communication, for example, when the originating relay device receives an on-hook signal from the telephone, a release complete message is transmitted to the terminating relay device. When receiving the release complete message, the relay device on the called side outputs a busy tone signal to the telephone connected thereto. After that, when an on-hook signal is received from the incoming side telephone set, a release complete message is returned to the outgoing side relay device.
[0024]
Next, the reception processing of the voice data after the call connection is completed will be described with reference to FIG.
[0025]
When the Ethernet interface 11 receives the audio data, the audio data is sequentially stored in the reception packet data buffer 13a of the reception buffer 13. This audio data is data read as Ethernet frames as layer 2 data, but is analyzed up to the IP (Internet Protocol), UDP (User Datagram Protocol), and RTP packet layers by the CPU executing the control program. The Here, UDP is used for voice data, and voice communication is realized by RTP. When analyzing the RTP packet from the voice data, the CPU 15 stores the RTP packet in the fluctuation absorbing buffer 13b. The fluctuation absorbing buffer 13b is a FIFO buffer that temporarily accumulates and reproduces a specified amount of RTP packets, and is used to absorb fluctuations from the network. The RPT packets temporarily stored in the fluctuation absorbing buffer 13b are taken into the DSP 16 at regular intervals (10 ms). The 729 codec is decoded and reproduced as analog voice through the FXS interface 12 so that the telephone 1 can hear the voice.
[0026]
Next, the operation of the CPU 15 by the self-sustaining cutting program will be described according to the flowchart shown in FIG.
[0027]
First, the CPU 15 checks whether or not the setup message including capability information or the like includes presence information of the voice compression process. The presence / absence flag of the audio compression process is set to 1 (step 1). Next, when it is confirmed that RTP communication has been started (step 2), the no-communication timer is reset to 0 and then time measurement is started (step 3), and it is checked whether an RTP packet has been received (step 3). 4). If the RTP packet has been received, the no-communication timer is reset again (step 5), the RTP packet reception process by the control program described above is executed (step 6), and the process returns to step 4.
[0028]
If it is determined in step 4 that no RTP packet has been received, it is determined whether or not the time measured by the no-communication timer is equal to or longer than the no-communication timeout time (determination time) stored in the data memory 14. (Step 7) If the no-communication timeout period is exceeded, the presence / absence of no-voice compression processing is checked with a flag (Step 8). This flag is 0, that is, no-voice compression processing is performed on the received data. If it is determined that the network device or the like has failed, disconnection processing is executed and a busy tone signal is output from the DSP 16 to the telephone set 1 (step 9). When the caller hears a busy tone from the telephone set 1, the caller recognizes that the communication has been disconnected, and puts the handset in an on-hook state. As described above with reference to FIG. 4, when receiving the on-hook signal from the telephone set 1, the relay device 10 transmits a release complete message to the relay device 10 on the communication counterpart side. In this disconnection process, a busy tone signal may be output to the telephone set 1 and a lease complete message may be transmitted to the communication partner side relay apparatus without waiting for an on-hook signal from the telephone set.
[0029]
If it is determined in step 8 that the no-voice compression processing presence / absence flag is 1, that is, the voice data is subjected to voice compression processing, this no-communication continues in the no-voice state, and the no-voice compression As a result of performing the processing, it is determined that the failure is not due to a failure of the network device or the like, and the disconnection processing is not performed, and the process proceeds to Step 10.
[0030]
If it is determined in step 7 that the time measured by the no-communication timer is not equal to or longer than the no-communication timeout period, and if it is determined in step 8 that the no-voice compression processing presence / absence flag is 1, call connection It is determined whether or not the call is in progress (step 10). If the call is being connected, the process returns to step 4;
[0031]
As described above, in the present embodiment, even when a relay device 10 or a network device on the communication destination side has a failure such as a power-off, the reception status of the RTP packet is monitored during the call connection, When the RTP packet cannot be received, the disconnection is performed autonomously, so that the call can be avoided.
[0032]
By the way, in this embodiment, the no-communication timeout period is determined based on the maximum time of RTP packet reception intervals. This maximum time is related to how many RTP packets are multiplexed in an IP packet. The RTP packet is 10 ms voice data, and G. When the RTP packet is multiplexed with the IP packet with the 729 codec, as shown in FIG. 6, the time obtained by multiplying the number of multiplexing by 10 ms is the multiprocessing time. At present, the maximum multiplexing number is 20, so the maximum multiplexing time is 200 ms.
[0033]
In the present embodiment, the no-communication timeout time is set to 5 s or more in consideration of the maximum multiplexing time 200 ms and fluctuations in the network.
[0034]
Here, the no-communication timeout period is a fixed value, but may be determined according to the RTP packet multiplex processing time. In this case, it is preferable to look at the header of the RTP packet, recognize the multiplex number or multiplex processing time from this header, and determine the no-communication timeout time according to a rule predetermined for this multiplex processing time. As a rule for determining the non-communication timeout time, for example, when the multiprocessing time is 100 ms or less, the non-communication time-out time is 4 s, and when the multi-processing time exceeds 100 ms, the non-communication time-out time is 6 s. It is possible to set it.
[0035]
In the above embodiment, the telephone 1 is directly connected to the relay device 10, but the telephone 1 may be connected via a PBX (Private Branch Exchange), a public network, or the like. In these cases, the disconnection process in step 9 described above merely performs a disconnection process with the PBX or the public network, and does not output a busy tone signal from the relay apparatus to the telephone set. This is because the PBX or the public network side outputs a busy tone signal to the telephone when the disconnection process with the PBX or the public network is performed.
[0036]
In the above embodiment, the telephone 1 and the relay apparatus 10 are separate bodies. However, as a telephone capable of RTP communication, the above relay apparatus may be incorporated in the telephone.
[0037]
【The invention's effect】
According to the present invention, even when a relay device or network device on the communication destination side has a failure such as power-off, the RTP packet reception status is monitored during call connection, and the RTP packet cannot be received for a certain time or more. In such a case, since the disconnection process is executed autonomously, it is possible to avoid holding the call.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a configuration of a communication system in an embodiment according to the present invention.
FIG. 2 is a circuit block diagram of a relay device according to an embodiment of the present invention.
3 is a call control protocol H.264. It is explanatory drawing which shows the sequence at the time of the outgoing connection by 255Q931.
4 is a call control protocol H.264. It is explanatory drawing which shows the sequence at the time of the cutting | disconnection by 255Q931.
FIG. 5 is a flowchart showing the operation of the CPU by the self-sustained cutting program according to the embodiment of the present invention.
FIG. 6 is an explanatory diagram showing the relationship between the number of multiplexed RTP packets and the multiplexing processing time.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Telephone, 2 ... LAN line, 3 ... HUB, 10 ... Relay device, 11 ... Ethernet interface, 12 ... FXS interface, 13 ... Reception buffer, 14 ... Data memory, 15 ... CPU, 16 ... DSP.

Claims (4)

In a relay device that performs call control and RTP (Real-time Transport Protocol) control,
A reception status detecting means for detecting whether or not an RTP packet is not received for a predetermined time or more during communication by the RTP control;
When the reception status detection means detects that the RTP packet has not been received for the predetermined time or more, a communication disconnection processing means for executing a communication disconnection process with the counterpart device ;
Silence compression processing detecting means for examining a message based on the call control protocol when communicating with the counterpart device and detecting whether or not the communication based on the RTP control has been silence-compressed. ,
Even if the communication disconnection processing unit detects that the RTP packet has not been received for the predetermined time or longer by the reception status detection unit, the silence compression processing detection unit detects the silence compression processing. When it is detected that has been applied, the communication disconnection process with the counterpart device is not executed.
A relay device characterized by that. A telephone set comprising the relay device according to claim 1 incorporated therein. In a control program for a relay device that performs call control and RTP (Real-time Transport Protocol) control,
A silence compression processing detection step of examining a message according to the call control protocol when communicating with the counterpart device and detecting whether or not the communication by the RTP control has been subjected to silence compression processing;
A reception state detecting step of detecting whether or not an RTP packet has not been received for a predetermined time or more during communication by the RTP control;
It is a case where it is detected in the reception status detection step that the RTP packet has not been received for the predetermined time or longer, and communication by the RTP control is performed in the silence compression processing detection step. Communication disconnection processing step for executing communication disconnection processing when it is detected that it has not been subjected to,
A control program for a relay device, which causes an arithmetic processing device to execute the above. In a communication method for performing call control and RTP (Real-time Transport Protocol) control,
A silence compression processing detection step of examining a message according to the call control protocol when communicating with the counterpart device and detecting whether or not the communication by the RTP control has been subjected to silence compression processing;
A reception state detecting step of detecting whether or not an RTP packet has not been received for a predetermined time or more during communication by the RTP control;
It is a case where it is detected in the reception status detection step that the RTP packet has not been received for the predetermined time or longer, and communication by the RTP control is performed in the silence compression processing detection step. Communication disconnection processing step for executing communication disconnection processing when it is detected that it has not been subjected to,
A communication method characterized by comprising:

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