JP3875123B2 - IP telephone communication system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an IP telephone communication system that transmits and receives audio signals using an Internet protocol network (IP network), and in particular, multiplexes clock signals required in an IP telephone communication system and switches the clock signals. For automated systems.
[0002]
[Prior art]
In recent years, telephone communication has been carried out using an IP network, and not only can IP telephone devices communicate with each other via an IP network, but also an existing telephone and an existing telephone line (office line). There is known an IP telephone communication system capable of telephone communication with an IP telephone apparatus.
[0003]
FIG. 7 is a block diagram showing a configuration of a conventional IP telephone communication system.
In FIG. 7, 2 is an IP network, 7 is a first IP telephone apparatus, 8 is a second IP telephone apparatus, and 9 is an IP switching apparatus. First IP telephone device 7, second IP telephone device 8, and IP exchange device 9 are all connected to IP network 2. The IP exchange device 9 is also connected to the existing station line 6 to enable telephone communication between the existing telephone 5 and the first IP telephone apparatus 7 or the second IP telephone apparatus 8. The IP network 2 includes various IP-compatible switches, repeater hubs, routers, and the like.
[0004]
In the IP telephone communication system, voice signals are transmitted and received via the IP network 2 in packet units. Also, since each packet has a source address and a destination address in the header, for example, even when only one IP line is connected, packets from a plurality of IP telephone apparatuses 7, 8 etc. Multiplex communication is possible by dividing and transmitting / receiving. However, in order to transmit and receive packets handled by a plurality of IP telephone apparatuses 7 and 8 without error, it is necessary to synchronize the clocks of the IP telephone apparatuses 7 and 8 and the like. One type of clock packet C1, C2 is supplied from the exchange device 9 to each of the IP telephone devices 7, 8, etc.
[0005]
In FIG. 7, the clock signal used between the IP exchange device 9 and the first IP telephone device 7 is C1 so that it can be classified for each communication destination, and is used between the IP exchange device 9 and the second IP telephone device 8. The clock signal to be transmitted is C2, but the clock packet C1 and the clock packet C2 are clock packets having the same clock timing but different only in the transmission destination address. That is, the clock packet C1 and the clock packet C2 are packets that are broadcast by IP multicast, for example.
[0006]
In the IP exchange device 9, for example, an IP network interface 91 that converts a voice signal from the existing telephone 5 into a packet signal that can be transmitted by the IP network 2 or performs reverse conversion, and the IP network interface. 91 is connected to the control bus 91 to control the transmission of the clock packet C1 and the clock packet C2, control the transmission and reception of other voice signal packets, and further control the overall operation in the IP switching device 9. 15 is provided.
[0007]
The IP network interface 91 further includes a clock packet generation unit 911 that generates clock packets C1 and C2 for each transmission destination, and an IP network interface that serves as a transmission source address stored in the header of each of the clock packets C1 and C2. It has an address storage unit 912 that accommodates 91 addresses.
[0008]
Within the first IP telephone device 7, a communication control unit 71 that receives a clock packet C 1 and transmits / receives a packet such as an audio signal, a clock detection unit 73 that detects a clock signal from the received clock packet C 1, and a communication control unit 71. And a control unit 72 that controls the operation of the clock detection unit 73.
[0009]
In the second IP telephone apparatus 8, similarly to the first IP telephone apparatus 7, the communication control unit 81 that receives the clock packet C 2 and transmits / receives the packet of the audio signal and the clock signal from the received clock packet C 2 are detected. A clock detection unit 83 and a control unit 82 that controls the operation of the communication control unit 81 and the clock detection unit 83 are provided.
[0010]
When the first IP telephone apparatus 7 receives the clock packet C1 and the clock detection unit 73 detects the clock signal, the first IP telephone apparatus 7 transmits the subsequent audio signal packet in synchronization with the clock signal. Similarly, when the second IP telephone apparatus 8 receives the clock packet C2 and detects the clock signal by the clock detector 83, it transmits the subsequent audio signal packet in synchronization with the clock signal.
[0011]
Then, since the packet transmitted from the first IP telephone device 7 and the packet transmitted from the second IP telephone device 8 are transmitted in synchronization with the clock signal at the same timing, the packet is lost during transmission through the IP network 2. Situations and the like are reduced, and deterioration of communication quality can be prevented.
[0012]
[Problems to be solved by the invention]
However, since the IP network 2 is connected to many communication devices and computers in addition to the first IP telephone device 7, the second IP telephone device 8, or the IP switching device 9, the IP telephone communication system. Thus, the entire bandwidth of the IP network 2 cannot be occupied and used. Therefore, no matter how much the synchronization between the devices constituting the IP telephone communication system is improved, for example, a packet being transmitted may be lost due to a packet transmitted from another device. Further, there is a case where the packet is lost due to a malfunction of the IP network 2 itself, or a packet is lost due to a malfunction of the IP network interface 91 in the IP exchange apparatus 9.
[0013]
In the conventional IP telephone communication system shown in FIG. 7, there is one clock packet generation unit 911, and the first IP telephone apparatus is transmitted by the clock packet C1 or the clock packet C2 transmitted from the one clock packet generation unit 911. 7 or the second IP telephone device 8 was synchronized. Therefore, for example, if the clock packet C1 or the clock packet C2 is lost due to the above-described problem, the first IP telephone device 7 or the second IP telephone device 8 cannot synchronize the voice signal packet, and the communication quality In the worst case, communication was impossible.
[0014]
The present invention has been made to solve the conventional problems as described above, and an object thereof is to provide an IP telephone communication system in which communication quality is hardly deteriorated even when a clock packet is lost.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, an IP telephone communication system according to the present invention described in claim 1 includes an IP switching apparatus connected to a circuit network (IP network) in which communication is performed using the Internet protocol (IP), and an IP An IP telephone communication system comprising a plurality of IP telephone apparatuses connected to a network, wherein the IP switching apparatus can generate a clock packet including a unique address and send it individually to the IP network for each unique address. A plurality of IP network interfaces are provided, the first priority order clock packet and the second priority order clock packet are transmitted from at least two IP network interfaces, and the IP telephone apparatus receives the first priority order from the received packet. A first priority order clock detection unit for detecting a clock signal; and a second priority order clock signal for detecting a second priority order clock signal from the received packet. The forward clock detection unit, the time until the next clock signal is received for the first priority clock signal, and the time until the next clock signal is received for the second priority clock signal are individually set. The IP switching device indicates that the clock signal has been disconnected when the time until the reception of the next clock signal in the first priority order or the second priority order exceeds a predetermined time by the reception timer to be measured and the reception timer. And a clock disconnection notification unit for notifying to each other.
[0016]
According to a second aspect of the present invention, in the IP telephone communication system according to the first aspect, when the IP switching apparatus is notified from the IP telephone apparatus that the clock signal of the first priority order has been disconnected, The second priority clock signal is changed to the first priority clock signal, the second priority clock signal is transmitted from the newly set IP network interface, and is changed to the IP telephone apparatus. It is characterized by notifying the unique address of the IP network interface and the unique address of the newly set IP network interface.
[0017]
According to a third aspect of the present invention, in the IP telephone communication system according to the first aspect, when the IP switching apparatus is notified by the IP telephone apparatus that the second priority clock signal has been cut off, A clock signal in the second priority order is transmitted from the set IP network interface, and a unique address of the newly set IP network interface is notified to the IP telephone apparatus.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on illustrated embodiments.
FIG. 1 is a block diagram showing a configuration of an IP telephone communication system according to an embodiment of the present invention.
In FIG. 1, parts having the same functions as those in the conventional IP telephone communication system shown in FIG.
[0019]
The IP telephone communication system of FIG. 1 includes at least one IP switching apparatus 1 connected to an IP network 2 and a plurality of IP telephone apparatuses (a first IP telephone apparatus 3 and a second IP telephone apparatus connected to the IP network 2). 4,... It is assumed that IP exchange apparatus 1, first IP telephone apparatus 3, and second IP telephone apparatus 4 all support IP multicast.
[0020]
The IP exchange apparatus 1 includes a plurality of IP network interfaces (first IP network interface 11 to fourth IP network interface 14), and each is connected to the control unit 15 via a control bus.
[0021]
The basic internal configuration of each IP network interface in the IP exchange apparatus 1 of the present embodiment is the same. For example, in addition to the configuration for transmitting and receiving basic communication packets as the IP network interface, for example, the first IP network interface 11 Includes a clock packet generation unit 111 that generates and transmits a clock signal necessary for the IP telephone apparatus to synchronize, an address storage unit 112 that stores an address of the first IP network interface 11, and a clock packet generation unit. A main / sub setting unit 113 is provided for setting whether the clock signal generated at 111 and sent to the IP network 2 is a main clock signal or a sub clock signal for the target IP telephone apparatus.
[0022]
Each of the clock packet generators 111, 121, 131, and 141 generates a clock packet including a unique address stored in each of the address storage units 112, 122, 132, and 142, and Each unique address can be sent separately to the IP network.
[0023]
As shown in FIG. 1, when there are two types of clock signals, ie, primary and secondary (first priority clock signal and second priority clock signal), the control unit 15 of the IP switching apparatus 1 uses the first IP network interface. Two IP network interfaces are selected from the 11th to 4th IP network interfaces 14, a clock packet of a main clock signal is transmitted from one IP network interface, and a clock packet of a sub clock signal is transmitted from the other IP network interface. Is sent out. Similarly, when there are three types of clock signals, the control unit 15 selects three IP network interfaces and sets the first to third priorities for the clock packet output of each interface. good.
[0024]
The basic internal configuration of each IP telephone apparatus according to the present embodiment is the same. As the IP telephone apparatus, basic communication packets are transmitted to and received from the IP network 2, and communication packets and voice signals are converted. On the other hand, in addition to the communication control unit 31 and the control unit 32 configured to input and output audio signals, a main clock detection unit 33, a sub clock detection unit 34, a reception timer 35, and a clock loss notification unit 36 are provided. ing.
[0025]
For example, in the first IP telephone device 3, the main clock detection unit 33 detects a clock signal (main clock signal) in the first priority order from the received packet. The sub clock detection unit 34 detects a clock signal (sub clock signal) in the second priority order from the received clock packet.
[0026]
The reception timer 35 individually measures the time until the next clock signal is received for the first priority clock signal and the time until the next clock signal is received for the second priority clock signal. The clock interruption notifying unit 36 detects that the reception timer 35 has exceeded the predetermined time for receiving the next clock signal for each clock signal in the first priority order or the second priority order. In this case, the IP switching device is notified that the clock signal in which the time excess has been detected is cut off (cannot be received).
[0027]
The second IP telephone device 4 also includes a main clock detection unit 43, a sub clock detection unit 44, a reception timer 45, and a clock disconnection notification unit 46, which have the same functions as the first IP telephone device 3.
[0028]
Next, the operation of this embodiment will be described.
FIG. 2 is a diagram showing how a normal clock signal is transmitted in the IP telephone communication system of FIG.
[0029]
FIG. 2 shows a case where the first IP telephone device 3 and the second IP telephone device 4 are communicatively connected via the IP network 2 and the IP switching device 1. The communication connection between the first IP telephone device 3 and the second IP telephone device 4 is established (the line is connected). In the IP exchange device 1, the control unit 15 assigns the first IP network interface 11 for the main clock signal, The network interface 12 is assigned for the secondary clock signal.
[0030]
The first IP network interface 11 generates a clock packet including the address of the first IP network interface 11, sends it to the first IP telephone device 3 as a clock packet MC 1, and sends a clock to the second IP telephone device 4. It is sent out as packet MC2. For example, broadcast transmission may be performed by IP multicast.
[0031]
The second IP network interface 12 generates a clock packet including the address of the second IP network interface 12 and sends it to the first IP telephone device 3 as a clock packet SC1. It is sent out as a packet SC2.
[0032]
In the first IP telephone apparatus 3, when the clock packet MC1 and the clock packet SC1 are received by the communication control unit 31, the main clock detection unit 33 detects the main clock signal from the clock packet MC1, and the sub clock detection unit 34 detects the clock packet. A sub clock signal is detected from SC1.
[0033]
In the first IP telephone apparatus 3, while both the main clock signal and the sub clock signal are detected, all packets received by the main clock signal are synchronized, and the sub clock signal is rejected. In this case, the clock loss notification unit 36 does not operate.
[0034]
The reception timer 35 individually measures the time from reception of one clock signal to reception of the next clock signal for each of the main clock and the sub clock. Then, when reception of the next clock signal is confirmed, time measurement from the reception of the signal is newly started again.
[0035]
FIG. 3 is a diagram showing a signal from the first IP telephone apparatus 3 when the main clock signal is disconnected in the IP telephone communication system of FIG.
In FIG. 3, the main clock detection unit 33 of the first IP telephone device 3 does not detect the main clock signal, and the sub clock detection unit 34 detects the sub clock signal. In this case, the control unit 32 of the first IP telephone device 3 confirms that the main clock signal is not detected for a predetermined time or longer by the reception timer 35 and determines that it is a packet arrival error. 1 of the second IP network interface 12 is notified by the event packet EV1 that the main clock has been turned off.
[0036]
FIG. 3 shows the case where the event packet EV1 from the first IP telephone apparatus 3 notifies the IP switching apparatus 1 that the main clock has been cut off. However, the event packet from the second IP telephone apparatus 4 It is also conceivable to notify the IP switching device 1 that the clock has been cut off. In that case, the event packet EV1 of FIG. 3 is changed so as to be output from the second IP telephone apparatus 4, and each configuration in the first IP telephone apparatus 3 described above is changed to each configuration in the second IP telephone apparatus 4. Should be read as
[0037]
FIG. 4 is a diagram showing a signal from IP switching apparatus 1 when the main clock signal is disconnected in the IP telephone communication system of FIG.
In the IP exchange apparatus 1, when the event packet EV 1 indicating that the main clock has been turned off is received by the second IP network interface 12, the control unit 15 sends the main clock of the sub clock signal to the second IP network interface 12. Signaling instructions (order) are output.
[0038]
The second IP network interface 12 instructs the first IP telephone device 3 to regard the clock signal (clock packet) transmitted from the second IP network interface 12 as a main clock signal (order OD1), and the second IP telephone device 4 Is also instructed (order OD2) to regard the clock signal (clock packet) transmitted from the second IP network interface 12 as the main clock signal.
[0039]
For example, when the first IP telephone apparatus 3 and the second IP telephone apparatus 4 receive a clock packet including the address of the second IP network interface 12 as a transmission source address, the OD1 and OD2 are the main clock signals included in the packets. This is an instruction for determining a clock signal.
[0040]
The control unit 15 of the IP exchange apparatus 1 also outputs an instruction (order) to the third IP network interface 13 so as to newly generate and send a packet of the sub clock signal.
[0041]
The third IP network interface 13 instructs the first IP telephone device 3 to regard the clock signal (clock packet) transmitted from the own IP network interface (third IP network interface) 13 as a sub clock signal (order OD3). The second IP telephone apparatus 4 is also instructed (order OD4) to regard the clock signal (clock packet) transmitted from the own IP network interface (third IP network interface) 13 as a sub-clock signal.
[0042]
For example, when the first IP telephone apparatus 3 and the second IP telephone apparatus 4 receive a clock packet that includes the address of the third IP network interface 13 as a transmission source address, the OD3 and OD4 are subclocked from the clock signal included in the packet. This is an instruction for determining a clock signal.
[0043]
Thereafter, a clock packet is generated from the third IP network interface 13 by including the address of the second IP network interface 12, and is sent to the first IP telephone device 3 as a clock packet SC1, and to the second IP telephone device 4. It is sent out as a clock packet SC2.
[0044]
FIG. 5 is a diagram showing a signal from the first IP telephone apparatus 3 when the sub clock signal is disconnected in the IP telephone communication system of FIG.
In FIG. 5, the sub clock detection unit 34 of the first IP telephone apparatus 3 does not detect the sub clock signal, and the main clock detection unit 33 detects the main clock signal. In this case, the control unit 32 of the first IP telephone apparatus 3 confirms that the sub-clock signal is not detected for a predetermined time or longer by the reception timer 35 and determines that it is a packet arrival error. 1 of the first IP network interface 11 is notified by the event packet EV2 that the sub clock has been turned off.
[0045]
FIG. 5 shows the case where the event packet EV2 from the first IP telephone apparatus 3 notifies the IP switching apparatus 1 that the sub clock has been cut off. However, the event packet from the second IP telephone apparatus 4 It is also conceivable to notify the IP switching device 1 that the clock has been cut off. In that case, the event packet EV2 of FIG. 5 is changed so as to be output from the second IP telephone apparatus 4, and each configuration in the first IP telephone apparatus 3 described above is changed to each configuration in the second IP telephone apparatus 4. Should be read as
[0046]
FIG. 6 is a diagram showing a signal from IP switching apparatus 1 when the sub clock signal is disconnected in the IP telephone communication system of FIG.
In the IP exchange device 1, when the first IP network interface 11 receives the event packet EV2 indicating that the sub clock has been turned off, the control unit 15 particularly instructs the first IP network interface 11 (order). Is not output.
[0047]
However, the control unit 15 of the IP exchange apparatus 1 outputs an instruction (order) to the third IP network interface 13 to newly generate and send a packet of the sub clock signal.
[0048]
The third IP network interface 13 instructs the first IP telephone apparatus 3 to regard the clock signal (clock packet) transmitted from the own IP network interface (third IP network interface) 13 as a sub clock signal (order OD5). The second IP telephone apparatus 4 is also instructed (order OD6) to regard the clock signal (clock packet) transmitted from its own IP network interface (third IP network interface) 13 as a sub-clock signal.
[0049]
These OD5 and OD6 are the same as OD3 and OD4 in FIG. 4, for example, when the first IP telephone apparatus 3 and the second IP telephone apparatus 4 receive a clock packet including the address of the third IP network interface 13 as a source address. This is an instruction for determining that the clock signal included in the packet is the sub-clock signal.
[0050]
As described above, in the IP exchange device 1 according to the present embodiment, the clock packet is transmitted from both the first IP network interface 11 and the second IP network interface 12 to be duplicated, and one of the clock packets that causes inconvenience in communication connection is generated. Even if it does not reach, the other clock packet capable of communication connection arrives, so that the supply of the clock signal is not interrupted.
[0051]
Even when switching the supply of the clock packet from one to the other where the communication connection is inconvenient, the other communication connection can be switched while it is connected, so the supply of the clock packet is not changed even during the switching. There is no interruption and communication quality is not degraded.
[0052]
Further, in the present embodiment, the case where there is one IP switching device 1 has been described. However, the present invention is not limited to this, for example, when a plurality of IP switching devices are connected to the IP network 2. One of the IP switching devices may be operated as in the above-described embodiment, or a plurality of IP switching devices may be operated in a linked manner to operate as in the above-described embodiment. .
[0053]
Further, in the IP telephone apparatus according to the present embodiment, the case where a normal call is performed between two IP telephone apparatuses has been described. However, a case where a telephone conversation is performed in a conference format between three or more IP telephone apparatuses is also possible. This can be dealt with by adding an IP network interface in the IP exchange apparatus 1.
[0054]
Further, when communication connection is established between the IP telephone device 3 or 4 and the existing telephone 5, the present invention is implemented by implementing the above-described embodiment only for the IP telephone device 3 or 4. Can do.
[0055]
In the IP telephone apparatus according to the present embodiment, each clock packet transmitted to the IP network includes only an address. However, for example, a clock priority signal may be further included. The clock priority signal is, for example, when the clock signal is of two types, main and sub, whether the clock signal indicated by the clock packet is the main clock signal for the target IP telephone device, Or it is a signal which shows whether it is a subclock signal.
[0056]
When there are three types of clock signals, for example, the first priority order clock signal, the second priority order clock signal, and the third priority order clock signal are signals indicating the priority order. A packet including the first priority clock signal is a clock signal of the first priority order, a packet including the second priority order clock signal is a clock signal of the second priority order, and a packet including the third priority order clock signal is The clock signal becomes the third priority order.
[0057]
【The invention's effect】
As described above, according to the present invention, in the IP switching device, one of the first IP packet interface and the second IP network interface transmits the clock packet to be duplicated, and one of the clock packets has a problem in communication connection. Therefore, the other clock packet that can be communicably connected can be reached, so that the supply of the clock signal is not interrupted and the clock signal can be supplied stably.
[0058]
Further, according to the present invention, when switching the supply of clock packets, the communication connection can be switched while being connected, so that it is possible to eliminate the deterioration of communication quality due to the interruption of the supply of clock packets during the switching.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an IP telephone communication system according to an embodiment of the present invention.
FIG. 2 is a diagram showing how a normal clock signal is transmitted in the IP telephone communication system of FIG. 1;
FIG. 3 is a diagram showing a signal from the first IP telephone apparatus when the main clock signal is disconnected in the IP telephone communication system of FIG. 2;
4 is a diagram showing a signal from an IP switching device when a main clock signal is disconnected in the IP telephone communication system of FIG. 2; FIG.
5 is a diagram showing a signal from the first IP telephone apparatus when a sub-clock signal is cut off in the IP telephone communication system of FIG. 2. FIG.
6 is a diagram showing a signal from the IP switching apparatus when the sub clock signal is cut off in the IP telephone communication system of FIG. 2. FIG.
FIG. 7 is a block diagram showing a configuration of a conventional IP telephone communication system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 IP (Internet protocol) switching apparatus, 2 IP network, 3 1st IP telephone apparatus, 4 2nd IP telephone apparatus, 5 Existing telephone, 6 Existing station line, 11 1st IP network interface, 12 2nd IP network interface, 13 3rd IP network Interface, 14 fourth IP network interface, 15 control unit, 31, 41 communication control unit, 32, 42 control unit, 33, 43 main clock detection unit, 34, 44 sub clock detection unit, 35, 45 reception timer, 36, 46 Clock loss detection unit, 111, 121, 131, 141 Clock packet generation unit, 112, 122, 132, 142 Address storage unit, 113, 123, 133, 143 Main / sub setting unit, C1, C2 clock packet, MC1 to MC4 main Clock packet (including main clock signal), SC ~ SC4 Sub-clock packet (including sub-clock signal), ODS1 to ODS2 Instruction for control inside IP switching device (order), OD1 to OD4 IP switching device to IP telephone device (order), EV1 to EV2 IP phone Event notification from the device to the IP switching device.

Claims (3)

An IP telephone communication system comprising an IP switching apparatus connected to a line network (IP network) in which communication is performed using an Internet protocol (IP), and a plurality of IP telephone apparatuses connected to the IP network,
The IP exchange device
A plurality of IP network interfaces that can generate a clock packet including a unique address and send it to the IP network separately for each unique address,
Sending out a first priority clock packet and a second priority clock packet from at least two IP network interfaces;
The IP telephone device
A first priority clock detection unit for detecting a first priority clock signal from the received packet;
A second priority clock detection unit for detecting a second priority clock signal from the received packet;
A reception timer for individually measuring the time until the next clock signal is received for the first priority clock signal and the time until the next clock signal is received for the second priority clock signal;
Clock that notifies the IP switching device that the clock signal has been cut off when the time until the reception of the next clock signal in the first priority order or the second priority order exceeds a predetermined time by the reception timer. An IP telephone communication system comprising a disconnection notification unit. The IP exchange device
When it is notified from the IP telephone device that the first priority clock signal has been cut off,
The previous second priority clock signal is changed to the first priority clock signal,
Send a clock signal of the second priority order from the newly set IP network interface,
2. The IP telephone communication system according to claim 1, wherein the IP telephone device is notified of the changed unique address of the IP network interface and the newly set unique address of the IP network interface. The IP exchange device
When notified from the IP telephone apparatus that the second priority clock signal has been cut off,
Send a clock signal of the second priority order from the newly set IP network interface,
2. The IP telephone communication system according to claim 1, wherein a unique address of a newly set IP network interface is notified to the IP telephone apparatus.

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