JP2006074302A - Key telephone system and voice data communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a key telephone system capable of transmitting directly a voice packet between IP telephone machines located across a NAT router. <P>SOLUTION: A router 4 has a NAT function 41 and a port forward function 42. If one global IP address is assigned from an IP network 100, data destined to the prescribed port of the global IP are transferred to the assigned IP address in the LAN by the port forward function 42. The router 4 makes use of the port forward function 42, and the information of the port forward for each IP telephone 2, 3, 6, 7 is registered on the side of the key telephone device 1. In this way, the IP address converted by the router 4 is recognizable at the time of pass control on the side of the key telephone device 1. The pass control of each IP information telephone 2, 3, 6, 7 can be carried out with accurate information, and conversation pass control across the router 4 can be realized easily at low cost. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a key telephone system and a voice data communication method used therefor, and more particularly to a voice data communication method between IP telephones in a key telephone system that accommodates an IP (Internet Protocol) telephone.

  In recent years, IP telephones have become widespread along with broadband transmission paths. Along with this, a system that can accommodate an IP telephone has been proposed for a button telephone system that allows a small number of telephone lines to be used by a large number of telephones (see, for example, Patent Document 1).

  In addition, as an address resolution method when communication is performed via a NAT (Network Address Translation) router, a router that supports the u-PnP (universal-plug and play) protocol is used, and u-PnP or the like is transmitted from a network device. There is a method of making communication by referring to NAT conversion in the router or the like according to the protocol.

  On the other hand, in the case of direct communication between IP telephones, control data is communicated with a part that controls call control (in this case, a button telephone system), and voice data is directly communicated between IP telephones. .

JP 2003-283658 A

  In the above-described direct voice packet communication between IP telephones as described above, an IP address (a system that controls call control, in this case, a button telephone system) and RTP (Real-time Transport Protocol) packets are directly transmitted. The IP address (in this case, the partner IP telephone with which the call has been established) is different from the IP address for communication, and therefore, NAT conversion cannot be simply used when making a call over the router.

  Also, in the conventional voice packet communication, in order to establish a call path, the RTP packet is once terminated by a device that manages call control (in this case, a button telephone system), and the RTP packet is sent to the target IP phone. Add a forward function or switch to a router that supports a protocol that controls a special router such as uPnP, and the device that controls call control (in this case, the button telephone system) must also support the uPnP protocol. This will increase the cost of the system.

  Also, in an environment where security measures are taken at the router for IP network connection, the destination address of the control packet for controlling the IP telephone and the voice packet are different, so the router's NAT conversion function should be used. Voice communication becomes impossible.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a button telephone system capable of directly communicating voice packets between IP telephones straddling a NAT router and a voice data communication method used therefor, which solve the above problems.

  A button telephone system according to the present invention is a button telephone system that accommodates an IP (Internet Protocol) telephone set installed in a security environment for preventing unauthorized entry from the outside by a NAT (Network Address Translation) router. Means are provided for resolving addresses for direct communication of voice packets between an external IP telephone and an IP telephone in the NAT router.

  The voice data communication method according to the present invention is a voice data communication method used for a button telephone system that accommodates an IP (Internet Protocol) telephone set installed in a security environment for preventing unauthorized entry from the outside by a NAT (Network Address Translation) router. The button telephone system includes a step of resolving both addresses for direct communication of voice packets between the IP telephone outside the NAT router and the IP telephone inside the NAT router. .

  In other words, the button telephone system of the present invention makes the UDP (User Datagram Protocol) port number of an RTP (Real-time Transport Protocol) packet (voice packet) used for each IP (Internet Protocol) telephone unique within the button telephone system. When the IP telephone is registered with the button telephone system, the IP address and the RTP port number to be used are notified.

  In the key telephone system of the present invention, the port forward information set in the router and the global IP address information assigned to the router are also set in the key telephone system in advance, so that NAT (Network Address Translation) is established. When performing RTP (voice packet) communication with an IP phone at the end of the router, a call between IP phones in the same LAN (Local Area Network) as the key telephone system is performed according to the port forward information set in the router. In this case, communication is possible with the IP address obtained at the time of registration, and path control from the key telephone system side becomes possible. Furthermore, in the key telephone system of the present invention, the RTP port number to be used can be changed for each call by an instruction from the key telephone system.

  Therefore, in the key telephone system of the present invention, even in an inexpensive router that does not support u-PnP (universal-plug and play), the port forward function, which is a general function of the router, is used. Also in direct communication (Peer to Peer communication), it is possible to resolve the IP address of voice data.

  That is, in the button telephone system of the present invention, an RTP (voice packet) port number to be used for each IP telephone is uniquely specified, and the IP telephone set in the LAN is determined by the port forward function on the router for each port number. Direct call (Peer to Peer call) between IP phone in LAN and IP phone of WAN (beyond NAT router) by setting packet forward to IP address and port number Does not prepare a special router corresponding to the u-PnP protocol or the like, and terminates the voice packet in the button telephone system and forwards the packet to the target IP telephone without using a button for controlling the call. Data settings on the telephone system side and router settings Possible with pressure only.

  In this case, in the key telephone system of the present invention, the port forward information and the global IP address assigned to the router are stored in advance in the key telephone system. With this information, the button telephone system of the present invention enables voice path control with an IP address and RTP port number considering NAT conversion for an IP telephone outside the NAT router and an IP telephone in the LAN.

  In addition, in the key telephone system of the present invention, when a DHCP (Dynamic Host Configuration Protocol) server function is built in, the IP address of each IP telephone can be changed by the control of the key telephone system, and the RTP to be used Changing the port number also prevents eavesdropping at the fixed IP address / fixed port, so simple security can be achieved by periodically changing the IP address and RTP port number used by the IP phone under the control of the key telephone system. It can be used as a function.

  With the configuration and operation as described below, the present invention provides an effect that voice packets between IP telephones straddling a NAT router can be directly communicated.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a button telephone system according to an embodiment of the present invention. In FIG. 1, a button telephone system according to an embodiment of the present invention is a system that allows a small number of telephone lines to be used by a large number of telephones in order to efficiently use a telephone line, and an IP (Internet Protocol) telephone network. Can be connected to.

  The button telephone system according to an embodiment of the present invention includes a button telephone device 1, IP telephones 2 and 3, and a router 4 for connecting the system to an IP network 100 through a firewall 5. IP telephones 6 and 7 are connected to the IP network 100.

  The button telephone apparatus 1 has a LAN (Local Area Network) interface, a DHCP (Dynamic Host Configuration Protocol) server function 11, a built-in call control unit 12 for controlling call control, and a device management unit 13 for managing network devices. And a database 14 for storing parameters for specifying the behavior of call control for each of the IP telephones 2 and 3.

  The telephones 2, 3, and 6 are telephones having a LAN interface, and perform data communication of control signals and voice data using an IP layer protocol. The telephone 7 is an IP softphone installed in a PC (personal computer), and the function is the same as that of the IP telephone.

  The router 4 has a NAT (Network Address Translation) function 41 and a port forward function 42, and when one global IP address is assigned from the IP network 100, the port forward function 42 sends a global IP address to a specific port. Is transferred to a designated IP address in the LAN.

  FIG. 2 is a table showing an IP address, a port number of each network device of FIG. In FIG. 2, the local IP address of the key telephone apparatus 1 is “X”, and the port number of the control data (signal data) is “M”. Similarly, the local IP address of the IP telephone 2 is “Y”, the RTP (Real-time Transport Protocol) port number is “y”, the local IP address of the IP telephone 3 is “Z”, and the RTP port number Is “z”.

  The IP telephone 6 is located on the WAN (Wide Area Network) side, the global IP address is “A”, the RTP port number is “a”, and the IP telephone 7 (IP softphone) is the global IP address “B”, RTP The port number is “b”.

  Also, one global IP address “C” is assigned to the router 4, no local IP address is required, and there is no problem in setting the IP address “D” of the default gateway. The port forward setting for passing through the LAN is performed by setting the data of the port “M” to the IP address “X” (button telephone apparatus 1) and the data of the port “x” to the IP address “X” (button telephone apparatus 1). It is set so that data of port “y” is port-forwarded to IP address “Y” (IP telephone 2), and data of port “z” is port-forwarded to IP address “Z” (IP telephone 3).

  FIG. 3 is a sequence chart showing an operation of registering information in the database 14 in the key telephone apparatus 1 of FIG. In FIG. 3, information matching the port forward setting in the router 4 is registered in the database 14 in the key telephone apparatus 1 in advance.

  In the registration operation, each IP telephone 2, 3, 6, 7 designates registration from the LAN or connection from the WAN, and the button telephone apparatus 1 requests registration from each IP telephone 2, 3, 6, 7 (Registration request) and IP / MAC (Media Access Control) address information, when the registration (registration) of the IP telephones 2, 3, 6, and 7 is permitted, the received IP address is stored, and the registration request A resist ACK (ACKnowledgement) (device management registration permission) is returned, and “RTP port number to be used” is notified.

  FIG. 4 is a view showing a list of the database 14 set in the key telephone apparatus 1 of FIG. In FIG. 4, there are system base data and data for each of the IP telephones 2, 3, 6, and 7 as the list types in the database 14.

  The system base data includes a signal port number designation (M), a global IP address designation (C) of the router 4 and a default gateway setting (D).

  In addition, RTP port numbers used by the IP telephones 2, 3, 6, and 7 are set in the IP telephone base data. This RTP port number needs to be set uniquely for each of the IP telephones 2, 3, 6, and 7.

  That is, for the IP telephone base data, the RTP port number to be used (IP telephone 2 = y, IP telephone 3 = z, IP telephone 6 = a), telephone number designation (IP telephone 2 = 1000, IP telephone 3 = 2000, IP telephone 6 = 3000, IP telephone 7 = 4000,...).

  FIG. 5 is a diagram showing device management data in the key telephone apparatus 1 of FIG. In FIG. 5, the device management unit 13 in the key telephone apparatus 1 specifies the MAC address, IP address, and connection form designation received from the IP telephones 2, 3, 6, and 7 when registering the IP telephones 2, 3, 6, and 7. Information is managed in units of IP telephones 2, 3, 6, and 7.

  In FIG. 5, the MAC address (O), IP address (Y), and connection type designation (LAN) of the IP phone 2, and the MAC address (P), IP address (Z), and connection type designation (LAN) of the IP phone 3 Managed by the MAC address (Q), IP address (A), and connection type designation (WAN) of the IP phone 6, and the MAC address (R), IP address (B), and connection type designation (WAN) of the IP phone 7. Has been.

  FIG. 6 is a flowchart showing the operation of direct connection (Peer to Peer connection) between IP telephones according to one embodiment of the present invention. FIG. 6 shows an operation of determining the IP address and RTP port number of the connection partner when the voice paths of two IP phones are actually directly connected between the IP phones.

  The IP phone asks for the IP address and RTP port number to notify the connection according to whether the IP phone of the bus connection partner is in the LAN or the WAN side, and whether the own IP phone is in the LAN or the WAN side. Do.

  FIG. 7 is a sequence chart showing the operation of dynamically changing the RTP (voice packet) port number used in one embodiment of the present invention. FIG. 7 shows an operation of dynamically changing the RTP (voice packet) port number to be used.

  After changing the call path, the button telephone device 1 searches for an available RTP port when changing the RTP to be used, and instructs the IP telephones 2, 3, 6, and 7 to change the “used RTP port number”.

  The operation of the button telephone system according to the embodiment of the present invention will be described with reference to FIGS. First, the database 14 is set in the key telephone device 1 (see FIG. 4).

  The database 14 in the key telephone apparatus 1 has “C” as the global IP address (router 4), “M” as the port number for signaling, “D” as the default gateway setting, and each IP phone 2, 3, 6, 7 Set the RTP port number to be unique.

  Next, the port forward setting of the router 4 is performed (see FIG. 2). In this case, the router 4 needs to have port forward settings corresponding to the number of IP telephones connected in the LAN or scheduled to be connected.

  In the port forward setting of the router 4, the RTP port number used by each IP phone 2, 3, 6, 7 is forwarded to the same RTP port number as the IP address in the LAN of each IP phone 2, 3, 6, 7 Is specified. In this case, setting of the IP telephone on the WAN side is unnecessary.

  Next, control processing in the key telephone device 1 will be described. Each IP telephone 2, 3, 6, 7 stores the IP address (global IP address) of the button telephone 1 on the side of each IP telephone 2, 3, 6, 7 before connecting to the key telephone 1 (see FIG. 3 a1). Thereafter, each of the IP telephones 2, 3, 6, and 7 performs a registration (registration request) operation to the key telephone device 1 by a registration operation. In this case, it is designated by a registration operation whether the connection is within the LAN or from the WAN (b2 in FIG. 3).

  After executing the registration operation, each of the IP telephones 2, 3, 6, and 7 sends a registration request command [including its own IP address / own MAC address and connection form (LAN or WAN)] to the key telephone apparatus 1 ( B3) in FIG.

  When the button telephone apparatus 1 receives the registration request command, the device management is performed from the MAC address / IP address and the connection form (LAN or WAN) of the IP telephones 2, 3, 6 and 7 received when it is determined that the IP telephone can be registered. Create a table (see a4 and FIG. 5 in FIG. 3)

  After that, the button telephone apparatus 1 obtains the RTP port number used by the registered IP telephones 2, 3, 6 and 7 from a pre-registered database (see FIG. 4) (a5 in FIG. 3), and a registration ACK command (use To the IP telephones 2, 3, 6, and 7 that have registered (including the RTP port number) (a6 in FIG. 3).

When the IP telephones 2, 3, 6, and 7 receive the registration ACK command, they store the RTP port number to be used (a7 in FIG. 3).
Next, a procedure for obtaining the IP address and RTP port number of the partner IP telephone in order to transmit and receive an RTP packet for establishing a call between the IP telephones 2, 3, 6, and 7 will be described.

  First, the IP telephones 2, 3, 6, and 7 obtain the connection form (LAN or WAN) of the IP telephone of the path connection partner, and then obtain the connection form (LAN or WAN) of the own IP telephone, and a combination of the results The path control is executed by determining the following procedure.

  The IP telephones 2, 3, 6, and 7 are connected to the path connection partner IP telephone and the own IP telephone in the LAN (steps S1 and S2 in FIG. 6), or the path connection partner IP telephone and the own IP telephone When the connection form is WAN (steps S1 and S4 in FIG. 6), the IP address registered and managed in the device management table (see FIG. 5) and the RTP port number used in advance registered in the database 14 (FIG. 4). The path connection control is instructed (see step S3 in FIG. 6).

  In addition, the IP telephones 2, 3, 6, and 7 are connected in the LAN when the connection form of the IP telephone of the path connection partner is in the LAN and the connection form of the own IP telephone is WAN (steps S1 and S2 in FIG. 6) or When the connection mode of the IP phone is WAN and the connection mode of the own IP phone is within the LAN, the global IP address (router 4) (see FIG. 4) registered in the system data and the database 14 registered in advance are used. The path control is instructed by the RTP port number (see FIG. 4) (step S5 in FIG. 6).

  Specifically, in the case of calls within the same form (within a LAN or within a WAN), the IP address registered at the time of registration is used as shown in step S3 above.

  In the case of a call over LAN-WAN, as shown in step S5 above, the IP address converted by port forwarding to the IP telephones 2 and 3 in the LAN is transferred to the IP telephones 6 and 7 on the WAN side. The global IP address assigned to the router 4 is notified. For the RTP port number, a number registered in advance is used consistently.

  As described above, in this embodiment, it is possible to establish a call between IP telephones exceeding the NAT router by the address resolution method of the IP address and the RTP port number as described above.

  As a simple security function, when there is an RTP port number that can be used by the setting on the key telephone device 1 when the call path is disconnected, the used RTP port number of the database 14 is changed and the IP telephones 2, 3 are used. , 6, 7 are instructed to change the used RTP port number, and IP telephones 2, 3, 6, 7 that have received the instruction change the stored used RTP port number and are effective from the next path connection. (B1 to b4 in FIG. 7).

  As described above, in this embodiment, the RTP (voice packet) port number used for each of the IP telephones 2, 3, 6 and 7 is uniquely specified, and the port forward function 42 on the router 4 is used for each port number. The packet is set to be forwarded to the IP address and port number of a predetermined IP phone in the LAN.

  Therefore, in this embodiment, the port forward information and the global IP address assigned to the router 4 are stored in advance in the key telephone apparatus 1. With this information, the button telephone device 1 can control the voice path with the IP address and RTP port number in consideration of NAT conversion for the IP telephones 6 and 7 outside the NAT router and the IP telephones 2 and 3 in the LAN. It becomes.

  Therefore, in this embodiment, direct (Peer to Peer) voice calls between IP telephones 2 and 3 in the LAN and IP telephones 6 and 7 in the WAN (beyond the NAT router) are compatible with u-PnP protocol and the like. Data setting and router on the side of the button telephone device 1 that controls the call without preparing a special router and without terminating the voice packet once in the button telephone device 1 and forwarding the packet to the target IP telephone. It becomes possible only by adding the setting.

  In the present embodiment, when the DHCP server function 11 is built in the key telephone device 1, the IP addresses of the IP telephones 2, 3, 6, and 7 can be changed by the control of the key telephone device 1. Further, by changing the RTP port number to be used, it is possible to prevent eavesdropping at the fixed IP address / fixed port.

  Therefore, in this embodiment, the IP address used by the IP telephones 2, 3, 6 and 7 and the RTP port number are periodically changed under the control of the button telephone apparatus 1, so that the system of this embodiment can be used as a simple security function. Can be used.

It is a block diagram which shows the structure of the button telephone system by one Example of this invention. It is a figure which shows the table | surface of the port address setting example of the IP address of each network device of FIG. 1, a port number, and a router. It is a sequence chart which shows the information registration operation | movement to the database in the button telephone apparatus of FIG. It is a figure which shows the list | wrist of the database set to the button telephone apparatus of FIG. It is a figure which shows the device management data in the button telephone apparatus of FIG. 6 is a flowchart showing an operation of direct connection between IP telephones according to an embodiment of the present invention. It is a sequence chart which shows the operation | movement which changes the RTP port number used in one Example of this invention dynamically.

Explanation of symbols

1 Button telephone device 2, 3, 6, 7 IP telephone
4 routers
5 Firewall
11 DHCP server function
12 Call controller
13 Device Management Department
14 Database
41 NAT function
42 Port forward function
100 IP network

Claims (10)

  A button telephone system that accommodates an IP (Internet Protocol) telephone set installed in a security environment for preventing unauthorized entry from outside by a NAT (Network Address Translation) router, the IP telephone outside the NAT router and the NAT router A button telephone system comprising means for resolving both addresses for direct communication of voice packets with an IP telephone in the system.   The means for resolving the address specifies an RTP (Real-time Transport Protocol) port number to be used for each IP phone, and transfers the RTP port number to an expected IP phone using the port forwarding function of the NAT router. The button telephone system according to claim 1, wherein the button telephone system is flexible.   By registering the port forward setting information for resolving the address, the global IP address of the NAT router, and the RTP port number used for each IP telephone, the RTP ports inside and outside of the NAT router are centrally managed, 3. The key telephone system according to claim 2, wherein the button telephone system is associated with an IP address for voice path control.   It includes means for obtaining an address for path control by designating whether the IP telephone is inside or outside the NAT router at the time of registration of the IP telephone, and within the LAN (Local Area Network) in the NAT router and the above 4. The button telephone system according to claim 1, wherein an address resolution method is used in combination with a WAN (Wide Area Network) side outside the NAT router.   Including a means for notifying each of the IP telephones of the set RTP port number to be used, enabling the RTP port number to be used to be controlled according to an instruction from the host device side, and dynamically changing the RTP port number for each call The button telephone system according to any one of claims 2 to 4, characterized in that:   A voice data communication method used for a button telephone system that accommodates an IP (Internet Protocol) telephone set installed in a security environment for preventing unauthorized entry from the outside by a NAT (Network Address Translation) router, the button telephone system side And a method for resolving both addresses for direct communication of voice packets between the IP telephone outside the NAT router and the IP telephone inside the NAT router.   In the step of resolving the address, an RTP (Real-time Transport Protocol) port number to be used for each IP phone is designated, and the RTP port number is transferred to an expected IP phone using the port forwarding function of the NAT router. The voice data communication method according to claim 6, wherein the voice data communication method is flexible.   By registering the port forward setting information for resolving the address, the global IP address of the NAT router, and the RTP port number used for each IP telephone, the RTP ports inside and outside of the NAT router are centrally managed, 8. The voice data communication method according to claim 7, wherein the voice data communication method is associated with an IP address in voice path control.   The button telephone system includes a step of obtaining an address for path control by designating whether the IP telephone is inside or outside the NAT router at the time of registration of the IP telephone, and includes a LAN (in the NAT router ( 9. The voice data communication method according to claim 6, wherein an address resolution method based on a combination of a local area network (WAN) and a WAN (wide area network) side outside the NAT router is used. Including a means for notifying each of the IP telephones of the set RTP port number to be used, enabling the RTP port number to be used to be controlled according to an instruction from the host device side, and dynamically changing the RTP port number for each call The voice data communication method according to claim 7, wherein:

Images