KR100422375B1 - Method and system for establishing connections between terminals connected to network environments having different IP-addressing schemes - Google Patents

Abstract

A method and system are provided for establishing a connection between a first terminal connected to a router in a first network environment and a second terminal in a second network environment. In one embodiment, a connection is established from a first terminal to a server that is outside of the first network environment. The first terminal then sends a packet to the server via the router. The server then determines the IP address and port number used by the router to send the packet to the server. This IP address and port number are then sent to the second terminal to establish a connection to the first terminal.

Description

Methods and system for establishing connections between terminals connected to network environments having different IP addressing schemes having different IP-addressing schemes

The present invention relates to connection establishment between terminals, and more particularly, to connection establishment between terminals connected to a network environment having different Internet protocol (IP) addressing schemes.

In general, routers are used to connect network environments that use different IP-addressing schemes. For example, a virtual private network (VPN) router can be used to connect the terminal behind the router to the Internet. Terminals behind the router are assigned virtual-IP addresses rather than standard-IP addresses such as those assigned by InterNIC. Thus, when a terminal behind the router sends a packet to a terminal outside the VPN router, the virtual-IP address of the terminal behind the router is replaced by the real-IP address of the VPN router.

One problem with using a router is that terminals outside the router cannot initiate connections with terminals behind the router. For example, in the above VPN-network environment, the terminal behind the VPN router has only the virtual-IP address. Thus, a terminal outside the VPN router cannot initiate a connection with a terminal behind the VPN router.

The present invention relates to a method and system for establishing a connection between a first terminal in a first network environment and a second terminal in a second network environment. According to one aspect of the present invention, the first network environment and the second network environment use different Internet Protocol (IP) addressing schemes. Thus, the first terminal is connected to the router. In one embodiment, a connection is established from a first terminal to a server outside of the first network environment. The first terminal then sends a packet to the server via the router. The server then determines the IP address and port number used by the router to send the packet to the server. This IP address and port number are then sent to the second terminal to establish a connection to the first terminal.

1 is a block diagram of one embodiment of the present invention;

2 is a block diagram of another embodiment of the present invention;

3 is a block diagram of another embodiment of the present invention;

4 is a block diagram of another embodiment of the present invention;

5 is a flowchart.

Explanation of symbols for main parts of the drawings

100: IP telephone system 102,104: terminal

106: computer network 108: gatekeeper

110: gateway 110 112: telephone unit

114: MCU 116: interface program

118: microphone 120: speaker

122: CODEC 202,402: Router

302: firewall 406: first network environment

408: second network environment

The following description to help understand the present invention refers to a number of specific configurations, parameters, and the like. However, it will be understood that such descriptions are not intended to limit the scope of the present invention but to provide a description of more typical embodiments.

In one exemplary embodiment of the present invention, referring to FIG. 1, IP telephone system 100 includes terminals 102 and 104 connected to computer network 106. In this embodiment, terminals 102 and 104 are configured to perform IP-based telephony over computer network 106. In particular, the terminals 102 and 104 are configured to transmit and receive data via the computer network 106 in accordance with the H.323 standard established by the International Telecommunication Union (ITU), as described in more detail below.

The H.323 standard is provided for audio, video and data communications, but part of this standard relates to audio communications, which are primarily used for IP-based telephony. In particular, in accordance with the H.323 standard, terminals 102 and 104 are configured to support H.245 to overcome channel usage and characteristics. Terminals 102 and 104 are also configured to support Q.931 for calling and setting up signals.

Each terminal 102, 104 in this embodiment includes a microphone 118 and a speaker 120, respectively, configured to capture and reproduce audio signals. The microphone 118 and the speaker 120 may be manufactured integrally with the terminals 102 and 104. They may be fabricated with accessories that are selectively connected to terminals 102 and 104.

Each terminal 102, 104 also includes a coder / decoder (CODEC) 122 configured to convert analog signals into digital signals and vice versa. In this embodiment, the CODEC 122 is also configured to help signal compression according to the G.729 standard. However, any H.323 compliant signal compression routine can be used, such as G.711, G.723, or the like.

Each terminal 102, 104 further includes an interface program 116. In this embodiment, the interface program 116 includes a system control routine to perform communication in accordance with the H.323 standard, including H.245 and Q.931. The interface program 116 is configured to support the RTP / RTCP and Registration / Admission / Status (RAS) protocols. As described in greater detail, the interface program 116 may also include various additional routines for conducting telephony over the computer network 106.

In one embodiment, the interface program 116 may run like a computer software program written using the C programming language. However, it can be appreciated that the interface program 116 can be executed using any conventional programming language. For example, the interface program 116 can be executed using JAVA or PERL programming language. These programming languages have the advantage that they can operate independently of the operating system of the terminal on which their programs are executed.

In this embodiment, the interface program 116 can be downloaded from the web site and installed in the terminal 102 (104). However, the interface program 116 can be installed on the terminals 102 and 104 using any conventional method. For example, the interface program 16 may be distributed on any conventional storage medium, such as diskettes, compact discs, and the like.

Terminals 102 and 104 may include personal computers, such as desk-top computers, laptop-top computers, workstations, and the like. However, terminals 102 and 104 may include any device configured to communicate with computer network 106, such as a teleconferencing system, a personal digital assistance (PDA), Internet device, or the like. In addition, the terminals 102 and 104 need not all be the same type of device. For example, terminal unit 102 may be a workstation that runs a Unix operating system. The terminal unit 104 may be an Intel-based computer running a Microsoft Windows operating system manufactured by Microsoft Corporation of Redmond Washington. In addition, although terminals 102 and 104 have been described, IP telephony system 100 may include multiple terminals 102 and 104.

The IP telephony system 100 in this embodiment may also include a gatekeeper 108, a gateway 110, and a multipoint control unit (MCU) 114. As described in more detail below, these additional components of IP telephony system 100 are configured to perform IP-based telephony in accordance with the H.323 standard.

In particular, gatekeeper 108 may be configured to provide call control services to terminals 102 and 104. Gatekeeper 108 may be configured to translate aliases of a local area network (LAN) into an IP or IXP address. Gatekeeper 108 may also be configured to provide bandwidth management and to route calls.

Gateway 110 may be configured to provide switching between different kinds of terminals. For example, the gateway 110 may be connected to a telephone unit 112 that is connected to a public switched telephone network (PSTN). Thus, the gateway 110 may switch between the IP-based computer network 106 and the switch circuit-based PSTN. Gateway 110 may also perform call setup and clearing on both LAN and PSTN.

MCU 114 may be configured to support conferences between three or more terminals. Thus, MCU 114 may be configured to coordinate H.245 negotiation between terminals to determine general compatibility.

According to one aspect of the invention, the interface program 116 registers the terminals 102 and 104 when the terminals 102 and 104 are connected to the computer network 106. In particular, in the present embodiment, when the terminal 102 is connected to the computer network 106, the interface program 116 installed in the terminal 102 transmits a gatekeeper 108 to the gatekeeper 108 by sending a GQ (Gatekepper Request) to the gatekeeper 108. Register at). In response, the gatekeeper 108 sends a Gatekeeper Confirm (GCF) message to the terminal 102. Terminal 102 then sends a Registration Request (RPQ) message to gatekeeper 108. In response, the gatekeeper 108 sends a Registration Confirm (RCF) message to the terminal 102. In this embodiment all these messages (eg GRQ, GCF, RPQ and RCF messages) are sent using User Datagram Protocol (UDP). In the same way, the interface program 116 installed in the terminal 104 registers with the gatekeeper 108.

In this embodiment, the IP addresses of terminals 102 and 104 are registered with gatekeeper 108. In addition, additional data may be registered with the gatekeeper 108. For example, in a variant embodiment, a unique Personal Communication Number (PCN) is assigned to each terminal connected to IP telephony system 100.

Assume that terminals 102 and 104 register with gatekeeper 108 in the manner described, for example, terminal 102 wants to call terminal 104. The following description provides an example of establishing a connection between terminals 102 and 104 using the H.323 standard for a call from terminal 102 to terminal 104.

In this embodiment, the terminal 102 first sends an ARQ (Admission Request) message to the gatekeeper 108 requesting the IP address of the terminal 104. In response, the gatekeeper 108 sends an Admission Confirm (ACF) message to the terminal 104 which sends the IP address for the terminal 104. Terminal 102 then establishes a signal channel with terminal 104 using the H.225 standard. Terminal 102 then sends a call setup H.225 / Q.931 setup message. In response, terminal 104 sends a Ringing message H.225 / Q.931 setup message to terminal 102. The terminal 104 then sends a connection message H.225 / Q.931 setup message to the terminal 102. Terminal 102 then establishes a Transmission Control Protocol (TCP) connection with terminal 104 by establishing a signal channel using H.245. Terminal 102 then sends a terminal compatibility request message to terminal 104 using H.245. In response, terminal 104 sends a terminal compatibility acknowledgment (ACK). Terminal 102 then sends a master slave decision message to terminal 104 using H.245. In response, terminal 104 sends a master slave decision acknowledgment (ACK) using H.245. In this embodiment, ARQ and ACF messages are transmitted using UDP and the remaining messages are transmitted using TCP.

In the above example, assume that terminals 102 and 104 have real IP addresses, each IP address being unique. If computer network 106 includes the Internet, a real IP address is assigned by the InterNIC, and the real IP address is unique to each terminal connected to the Internet.

However, in some applications of the present invention, terminal 102 and / or terminal 104 may have a virtual IP address. In particular, in another embodiment of the present invention, referring to FIG. 2, the terminal 102 may be connected to the computer network 106 through a virtual private network (VPN) router 202. As such, terminal 102 is assigned a virtual IP address rather than a real IP address. Thus, when terminal 102 transmits data to computer network 102, the data includes the real IP address of VPN router 202 rather than the virtual IP address of terminal 102. This can be a problem in conducting IP-based telephony between terminals 102 and 104.

To more clearly illustrate the above problem, for example, terminal 102 has a virtual IP address of 10.10.10.20 and VPN router 202 has a virtual IP address of 10.10.10.1 and a real IP address of 210.119.58.40. Suppose we have As mentioned above, when terminal 102 sends a packet to, for example, gatekeeper 108 or terminal 104, the IP address associated with the packet is determined by the VPN router 202 rather than the address of terminal 102. Real IP address (eg, 201.119.58.40). Thus, gatekeeper 108 and terminal 104 do not know the IP address of terminal 102. Moreover, terminal 102 does not know the real IP address of VPN router 202 used to transmit the packet. This may interfere with the transmission of audio packets according to the H.323 standard to perform IP-based telephony.

As a result, in one embodiment of the present invention, terminal 102 and gatekeeper 108 are configured to perform IP-based telephony using the H.323 standard even if terminal 102 is behind a VPN router 202. It is composed. In particular, the interface program 116 installed in the terminal 102 is configured to send packets to the gatekeeper 108. When this packet is received, gatekeeper 108 is configured to check it to determine the port number and IP address used to send the packet. The gatekeeper 108 then loads this information into another packet and sends it to the port number and IP address used to send the received packet. This subsequent packet is relayed to the terminal 102 by the VPN router 202. After this packet is received, the interface program 116 installed in the terminal 102 is configured to inspect it and obtain the port number and IP address used to send the original packet to the gatekeeper 108. With this information, terminal 102 can communicate using the H.323 standard with any terminal 104 or any terminal connected to computer network 106 to perform an IP-based telephony call.

To more clearly illustrate this aspect of the invention, terminal 102 has a virtual IP address of 10.10.10.20. And VPN router 202 has a virtual address of 10.10.10.1 and a real IP address of 210.119.58.40. Assume that Also assume that gatekeeper 108 has a real IP address of 211.104.18.60.

In this embodiment terminal 102 sends the packet to gatekeeper 108 via VPN router 202. In particular, a port is formed at the virtual IP address (eg, 10.10.10.20) of terminal 102 to transmit the packet (assuming that port is port number 1720). A port is also formed at the virtual router's virtual IP address (e.g., 10.10.10.1) to receive packets from terminal 102 (assuming this port is port number 2500). A port is also formed at the real IP address of the VPN router 202 (eg, 210.119.58.40) to send this packet to the gatekeeper 102 (assuming this port is port number 3000). To receive this packet, a port is also formed at the real IP address of the gatekeeper 108 (eg, 211.104.18.60) (assuming this port is port number 1720).

After receiving the packet, gatekeeper 108 examines the packet and determines if it was received via port number 3000 of IP address 210.119.58.40 (eg, VPN router 202). Gatekeeper 108 then locates this information in another packet and sends the packet to port number 3000 at IP address 210.119.58.40. Thus, this subsequent packet is received by VPN router 202 and routed to terminal 102 over port number 2500 at IP address 10.10.10.1. This packet is then received at port number 1720 at IP address 10.10.10.20. The interface program 116 of terminal 102 then examines this packet to obtain the port number and IP address used to send the original packet to the gatekeeper 108. Once this information is obtained, the terminal 102 can make an IP-based telephone call with the terminal 104 using the H.323 standard. Using the process described above, the terminal 102 may also be connected to the gateway 110 to perform an IP-based telephone call with the telephone unit 112 connected to the PSTN.

In another application of the present invention, referring to FIG. 3, terminal 102 may be connected to computer network 106 through firewall 302. Typically firewall 302 is a router configured to perform packet filtering. In this respect, the firewall 302 presents a similar problem as the VPN router 202 (FIG. 2) described above. In particular, the firewall 302 can function like a VPN router in that it has a virtual IP address and a real IP address. In such a case, when a terminal 102 assigned a virtual IP address rather than a real IP address transmits the packet to the computer network 106, the packet includes the real IP address of the firewall 302 rather than the terminal 102. As a result, IP-based telephony can be performed through the firewall 302 using the same process described above for the VPN router 202 (FIG. 2).

However, in some firewalls, one port is formed for sending packets and the other port is formed for receiving packets. If this is the case, then the process described above for VPN router 202 may not be used for firewall 302. However, according to another aspect of the present invention, the interface program may be configured to use the SOCKS protocol to enable IP-based telephony through the firewall when the firewall 302 supports the SOCKS protocol.

As mentioned above, for example, assume that terminal 102 wants to call terminal 104. Also assume that terminal 102 has a virtual IP address of 10.10.10.20 and firewall 302 has a virtual IP address of 10.10.10.1 and a real IP address of 210.119.58.40. When terminal 102 sends a packet to firewall 302, a port (assuming port number 1720) is formed at the terminal's virtual IP address (e.g., 10.10.10.20) to send the packet. In addition, a port (assuming port number 2500) is established at the virtual IP address (e.g., 10.10.10.1) of the firewall 302 to receive the packet. A port (assuming port number 3000) is also established at the real IP address of the firewall 302 (eg, 201.119.58.40). According to the SOCKS protocol, this port and IP address are transmitted to the terminal 102 by the firewall 302. Thus, terminal 102 may register this information with gatekeeper 108 and perform an IP-based telephony call with terminal 104 using the H.323 standard. Moreover, terminal 102 may also conduct IP-based telephony with telephony unit 112 connected to PSTN via gateway 110.

In the above description, it is assumed that the call was made from terminal 102, which is the rear end of firewall 302, to terminal 104, which is outside of firewall 302. However, the following description assumes that a call is made from terminal 104 to terminal 102.

In this embodiment terminal 102 forms a TCP / IP connection with gatekeeper 108 through firewall 302 using the SOCKS protocol process described above. In addition, this TCP / IP connection between the terminal 102 and the gatekeeper 108 is maintained continuously. Terminal 104 also forms a TCP / IP connection with gatekeeper 108, and this connection is persistent.

If terminal 104 wishes terminal 102 to call, then interface program 116 installed on terminal 104 to gatekeeper 108 using a TCP / IP connection between terminal 104 and gatekeeper 108. The terminal 104 indicates that it wants to connect with the terminal 102. When this message is received, using the TCP / IP connection established between the gatekeeper 108 and the terminal 102, the gatekeeper 108 wants the terminal 102 to connect to the terminal 102. Notify Gatekeeper 108 also sends the IP address of terminal 104 to terminal 102. The interface program 116 installed on the terminal 102 then notifies the firewall 302 to wait for an ongoing connection from the terminal 104 using the SOCKS bind function. In response, firewall 302 creates a port for connection with terminal 104 and sends the port number and IP address to terminal 102. The interface program 116 installed on the terminal 102 using the TCP / IP connection between the terminal 102 and the gatekeeper 108 may use the port 102 and the IP address received from the gatekeeper 108. Tells gatekeeper 108 to connect to. In response, gatekeeper 108 tells terminal 104 to connect to firewall 302 using the port and IP address received from terminal 102. Terminal 104 then establishes this connection to firewall 302. Firewall 302 proves to terminal 104 that the IP address and other information of terminal 102 before the connection is granted is true. When the connection between the firewall 302 and the terminal 104 is established, the firewall 302 sends a notification to the terminal 102. After receiving this notification, terminal 102 uses this connection between firewall 302 and terminal 104 to perform an IP-based telephone call.

In another embodiment of the present invention, interface program 116 and gatekeeper 108 may be configured to receive calls from telephone units connected to the PSTN. For example, assume that telephone unit 112 connected to the PSTN wants to call unit 102. The telephone unit 112 is also connected to a gateway 110 configured for switching between the IP-based computer network 106 and the PSTN.

In an embodiment of the present invention, the gateway 110 registers with the gatekeeper 108. In particular, the gateway 110 transmits a register request (RRQ) message to the gatekeeper 108. In response, the gatekeeper 110 transmits a Request Confirm (RCF) message to the gateway 110. As part of the RRQ message, the gateway 110 sends its IP address.

In addition, the terminal 102 registers with the gatekeeper 108 as described above. In particular, terminal 102 also sends a Register Request (RRQ) message to gatekeeper 108. In response, the gatekeeper 110 transmits a Request Confirm (RCF) message to the terminal 102. The terminal 102 may transmit its IP address and port number to the gatekeeper 108 through the firewall 303 using the predetermined process described above.

The gateway 110 sends an ARQ (Admission Request) to the gatekeeper 108 when the telephone unit 112 starts a call. In response, gatekeeper 108 sends an ARQ message to terminal 102 using the port number and IP address of terminal 102 previously registered. When the ARQ message is received, the interface program 116 installed in the terminal 102 binds the port to the firewall 302 and transmits the bound port information to the gatekeeper 108. In response, the gatekeeper 108 transmits a Registration Confirm (RCF) message to the terminal 102 and an ACF (Admission Confirm) message to the gateway 110. Gatekeeper 108 also transmits the port number and IP address of terminal 102 registered to gatekeeper 108 to gateway 110. As a result, the terminal 10 and the gateway 110 have IP addresses required to perform IP-based telephony using the H.323 standard.

In a typical embodiment of the present invention, the computer network 106 is the Internet. However, computer network 106 may include any network that combines private, public or private and public computer networks that operate using IP-based protocols. In addition, the above-described IP protocol may include IPv4, IPv6, and the like.

Thus far, the present invention has been described for performing an IP-based telephone call through a computer network. However, the present invention can also be used for various modifications of IP-based telephony.

In particular, referring to FIG. 2, a method and system related to an exemplary embodiment of the present invention for conducting IP-based telephony with a terminal 102 connected to a VPN router 202 is described. In this exemplary embodiment, terminal 102 is assigned a virtual IP address. Thus, when terminal 102 sends a packet, VPN router 202 (FIG. 2) replaces the virtual IP address of terminal 102 with the real IP address of VPN router 202 (FIG. 2). The interface program 116 installed on the terminal 102 to perform IP-based telephony with the terminal 102 may be configured to send packets to the gatekeeper 108 via the router 202. When the gatekeeper 108 receives this packet, the gatekeeper 108 determines the port number and IP address used by the router 202 to transmit the packet from the terminal 102.

As described above, the method and system outlined above have been described with regard to IP-based telephony, but the method and system can be used for a number of applications. The following description will describe a more general application for communication between two terminals in two different network environments using two different IP addressing schemes.

Referring to FIG. 4, the gatekeeper 108 may be configured to perform communication between terminals 102 and 104 according to the H.323 standard without performing a gatekeeper function. Thus, gatekeeper 108 will be referred to as server 108 in the following description. The gatekeeper (server) may be composed of a plurality of terminals, computers, processors, and the like.

According to one exemplary embodiment of the present invention, terminal 102 may be connected to server 108 via router 402. In this embodiment, the router 402 may be configured to translate the IP address used in the first network environment 406 into another IP address used in the second network environment 408. Accordingly, the router 402 may be configured as a virtual private network (VPN) router, a network address translation (NAT) router, or the like. In addition, the router 402 may be configured as part of a firewall.

As shown in FIG. 4, the terminal 102 and the router 402 reside in the network environment 406 while the server 108 is outside of the network environment 406. In particular, in this embodiment server 108 and terminal 104 reside within network environment 408. However, network environment 406 and network environment 408 may include a VPN environment, a NAT environment, a network behind the firewall, and the like. Moreover, server 108 may reside in a third network environment that is separate from network environment 406 and 408.

As noted above, the network environment 406 may use a different IP addressing scheme than the network environment 408. In addition, as described above, the router 402 may be configured to switch between different IP addressing schemes used within the network environment 406 and 408. Thus, if terminal 102 wishes to communicate with terminal 104, router 402 converts the IP addressing scheme used in network environment 406 to the IP addressing scheme used in network environment 408. However, terminal 104 cannot initiate communication with terminal 102 that does not have the IP address of terminal 102 in network environment 406.

Thus, the method and system related to the implementation of an IP-based telephony between terminals 102 and 104 may be used to permit terminal 104 to initiate communication with terminal 102. For clarity and convenience only terminals 102 and 104 are described next and shown in FIG. 4. However, the present invention may be used to effect communication between multiple terminals 102 and 104.

Referring to FIG. 4, in this embodiment, the terminal 102 may be configured to establish an initial connection with the server 108 (block 502 of FIG. 5). As noted above, terminal 102 may include an interface program 116 configured to establish a connection with server 108. This initial connection can be established when the interface program 116 is first mounted and driven in the terminal 102. In one embodiment this initial connection may be established using the TCP / IP protocol. One of the advantages of using the TCP / IP protocol is that the connection between terminal 102 and server 108 is maintained. In particular, the router 402 in this embodiment opens a port for connecting the terminal 102 to the server 108. Router 402 keeps this port open if TCP / IP protocol is used. However, if the UDP protocol is used, the router closes this port in a short time, for example within a few minutes. Thus, in another embodiment, if the UDP protocol is used to establish an initial connection between the terminal 102 and the server 108, the interface program 116 may repeatedly send packets to the server 108 to maintain this connection. Can be configured. In particular, the interface program 116 may be configured to repeatedly send packets to the server 108 before the router 402 closes open ports to establish an initial connection between the terminal 102 and the server 108. Can be. For example, the interface program 116 may be configured to send a packet to the server 108 every minute. The interface program 116 may be configured to transmit packets within some convenient time, such as every few seconds, every few minutes, and the like. In addition, server 108 may send a packet to maintain a connection between terminal 102 and server 108.

Once the connection between the terminal 102 and the server 108 is established, the interface program 116 within the terminal 102 may be configured to send packets to the server 108 via the router 402 (block 504 of FIG. 5). have. In particular, terminal 102 sends a packet to server 108 via router 402. When the router 402 sends a packet from the terminal 102 to the server 108 it switches from the IP addressing scheme used in the network environment 406 to the IP addressing scheme used in the network environment 408. Router 402 also assigns a port for transmitting packets from terminal 102 to server 108.

Thus, when this packet is received, server 108 checks it to determine the IP address and port number used by router 402 to send this packet from terminal 102 (block 506 in FIG. 5). Can be configured. Server 108 may include any conventional software and / or hardware for determining the IP address and port number used by router 402.

After this IP address and port number have been determined, server 108 may send this information to terminal 104 (block 508 of FIG. 5). Using the IP address and port number transmitted by the server 108, the terminal 104 may establish a connection with the terminal 102 behind the router (block 510 of FIG. 5). In this method, a terminal 104 in a network environment 408 having one IP addressing scheme may establish a communication with a terminal 102 in a network environment 406 having another IP addressing scheme.

The server 108 may also be configured to store the IP address and port number used by the router 402 to send packets from the terminal 102. Thus, if terminal 104 wishes to communicate with terminal 102, terminal 104 may send a request to server 108 and transmit an IP address and port number associated with terminal 102.

In particular, in one embodiment of the present invention, a unique identification code may be assigned to a user of the terminal 102 (104). When the interface program 116 is connected to the server 108, the interface program 116 may transmit a unique identification code associated with the user of the terminal 102 to the server 108. Server 108 may then store this identification code with the IP address and port number associated with terminal 102. Thus, if a user of terminal 104 wishes to communicate with a user of terminal 102, an identification code associated with the user of terminal 102 may be included in the request sent from terminal 104 to server 108. Aliases may be associated with an identification code assigned to a user of terminals 102 (104). In addition, an identification code may be assigned to terminals 102 and 104 rather than to a user. See US Patent Application Serial No. 09 / 557,746, "METHOD AND APPARATUS FOR CONDUCTING COMPUTER TELEPHONY," filed April 24, 2000, for a more detailed description of such identification code systems.

As noted above, in one embodiment of the present invention, server 108 may be configured to send an IP address and port number associated with terminal 102 to terminal 104 upon receiving a request from terminal 104. In this embodiment, the router 402 may be configured to maintain the open state of the port used to send packets from the terminal 102 to the server 108, such as when using the TCP / IP protocol. However, in some applications router 402 may be configured to immediately close this port after sending a packet from terminal 102 to server 108, such as when using the UDP protocol. For example, if router 402 is part of a firewall, the port used to send packets from terminal 102 to server 108 may be closed within minutes. In such an application, terminal 104 preferably establishes a connection with terminal 102 using the address and port number received from server 108 before the port is closed.

In particular, in one embodiment of the invention, the terminals 102 and 104 may be configured to establish an initial connection with the server 108. In particular, as described above, the terminals 102 and 104 may include an interface program 116 configured to connect the terminals 102 and 104 to the server 108. This initial connection can be established when the interface program 116 is first mounted or driven in the terminal 102 (104). In this embodiment this initial connection is established using the TCP / IP protocol. As noted above, in other embodiments such an initial connection may be established using the UDP protocol.

In this embodiment, if terminal 104 wishes to initiate communication with terminal 102, interface program 116 of terminal 104 may be configured to send a request to server 108. When terminal 104 sends this request to server 108, a port is opened at terminal 104 and server 108. When server 108 receives this request, server 108 may be configured to determine the address and port number of terminal 104 used to send this request. Server 108 may be configured to store this address and port number.

After receiving the request from terminal 104, server 108 may be configured to send the request to interface program 116 of terminal 102. In this embodiment, server 108 may send this request to terminal 102 via an initial connection established with terminal 102.

In response to this request of the server 108, the interface program 116 of the terminal 102 may be configured to send a packet to the server 108 via the router 402. When terminal 102 sends this packet, router 402 opens a port to send the packet to server 108.

When the server 108 receives this packet, the server may be configured to determine the address and port number of the router 402 used to transmit the packet. The server 108 then sends this address and port number to the terminal 104, in particular to the interface program 116 within the terminal 104. The server 108 may send this information to the terminal 104 through the initial connection established with the terminal 104.

Using the IP address and the port number received from the server 108, the terminal 104 may establish a connection with the terminal 102 behind the router 402. In this method, the terminal 104 in the network environment 408 with one IP addressing scheme may establish a connection with the terminal 102 in the network environment 406 with another IP addressing scheme.

In this embodiment server 108 may be configured to store an IP address and a port number associated with terminal 102. In addition, the above-described identification code scheme can be used in this embodiment.

Although the present invention has been described with respect to specific embodiments shown in the accompanying drawings, various modifications may be made without departing from the spirit and scope of the invention. Accordingly, the present invention should not be reduced as limited to the specific forms shown in the drawings and description above.

As described above, the present invention can communicate by establishing a connection between a terminal in a network environment having one IP addressing scheme and a terminal in a network environment having another IP addressing scheme.

Claims (35)

A first network environment in which a first terminal is connected to a router; In a method for establishing a connection between second terminals in a second network environment: Establishing a connection with a first terminal in the first network environment; Receiving a packet from a first terminal through the router; Determining an IP address and a port number used by the router to transmit the packet; And transmitting the determined IP address and port number to the second terminal so that the connection setting from the second terminal to the first terminal is made. The method of claim 1 wherein the method is: Storing the IP address and port number; Receiving a request from a second terminal to connect to the first terminal; And Transmitting the stored IP address and port number to the second terminal. 3. The method of claim 2, wherein the first terminal, the second terminal, and the server communicate using Transmission Control Protocol / Internet Protocol (TCP / IP). The method of claim 1 wherein the method is: Establishing a connection with the second terminal; Receiving a request from the connected second terminal; And Sending a request to the first terminal; The request is transmitted using a connection from a first terminal to the server, and a packet transmitted from the first terminal to the server is transmitted according to the request transmitted from the server to the first terminal. The method of claim 4 wherein the method is: Storing the IP address and the port number. 5. The method of claim 4, wherein the first terminal, the second terminal, and the server communicate using a User Datagram Protocol (UDP) protocol. 2. The method of claim 1, wherein the connection established from the first terminal to the server is established using a TCP / IP protocol. 2. The method of claim 1, wherein the connection established from the first terminal to the server is established using User Datagram Protocol (UDP). 9. The method of claim 8, further comprising repeatedly receiving a packet from a first terminal. The method of claim 1, wherein the first network environment is a virtual private network (VPN) environment. The method of claim 1, wherein the first network environment is a network address translation (NAT) environment. The method of claim 1 wherein the first network environment is a firewall environment. A first terminal in a first network environment having a first IP addressing scheme coupled to a router configured for switching between the first and second Internet Protocol (IP) addressing schemes, and a second IP addressing scheme; A method of establishing a connection between a first terminal and a second terminal executable on a server in a second network environment having: Establishing an initial connection with the first terminal; Receiving a request from the second terminal; Sending a request to the first terminal according to the request sent from the second terminal using an initial connection established with the first terminal; Receiving a packet from a first terminal through a router according to the request; Determining an IP address and a port number used by a router to receive the packet; And transmitting the determined IP address and a port number to the second terminal to establish a connection from the second terminal to the first terminal. 14. The method of claim 13, further comprising storing the determined IP address and port number. 14. The method of claim 13, wherein a request from a second terminal is sent from an interface program installed in the second terminal, and a request to the first terminal is sent to an interface program installed in the first terminal. . The method of claim 13, further comprising establishing an initial connection with the second terminal, wherein an IP address and a port number transmitted to the second terminal are transmitted using an initial connection between the second terminal and the server. How to feature. 17. The method of claim 16, wherein the initial connection established between the first terminal and the second terminal and the server is established using a Transmission Control Protocol / Internet Protocol (TCP / IP) protocol. 18. The method of claim 17, wherein the request sent from the second terminal to the server, the request sent from the server to the first terminal, and the packet sent from the first terminal to the server use a User Datagram Protocol (UDP) protocol. And characterized in that the transmission is carried out. The method of claim 13, wherein the initial connection established between the first terminal and the server is established using a TCP / IP protocol. The method of claim 13, wherein the initial connection established between the first terminal and the server is established using a UDP protocol. 21. The method of claim 20, further comprising repeatedly transmitting a packet from the first terminal to the server. The method of claim 13, wherein the first network environment is a virtual private network (VPN) environment. 15. The method of claim 13, wherein the first network environment is a network address translation (NAT) environment. 14. The method of claim 13, wherein the first network environment is a firewall environment. Connection between the first terminal in the first network environment and the second terminal in the second network environment using an Internet Protocol (IP) addressing scheme different from the first network environment and the second network environment is connected to the router. On a system configured to set up: A server existing outside of the first network environment; A first interface program installed in a first terminal, the first interface program configured to establish a connection with the server and send a packet to the server via a router, the server configured to send a packet to the server Determine an IP address and a port number to be used by; A second interface program installed in a second terminal, wherein the server is configured to transmit an IP address and a port number to the second interface program, wherein the second interface program uses the IP address and port number received from the server; And establish a connection with the first interface program. 27. The system of claim 25, wherein the server is configured to store an IP address and a port number. 27. The method of claim 26, wherein the second interface program is configured to send a request to the server to connect to the first interface program, wherein the server is an IP address and a port number stored in the second interface program according to the request. The system, characterized in that configured to transmit. 26. The method of claim 25, wherein the second interface program is configured to establish a connection with the server and send a request to the server using the connection established with the server, the server to the request of the first interface program. And according to the request of the server, the second interface program is configured to send the packet to the server according to the request of the server. 29. The system of claim 28, wherein said server is configured to store an IP address and a port number. 27. The system of claim 25, wherein the first interface program is configured to establish a connection with the server using a Transmission Control Protocol / Internet Protocol (TCP / IP) protocol. 27. The system of claim 25, wherein the first interface program is configured to establish a connection with the server using a User Datagram Protocol (UDP) protocol. 32. The system of claim 31, wherein the first interface program is configured to repeatedly transmit a packet to the server to maintain a connection with the server. 27. The system of claim 25, wherein the router is configured as a virtual private router (VPN) router. 27. The system of claim 25, wherein the router is configured as a network address translation (NAT) router. 27. The system of claim 25, wherein the router is configured as part of a firewall.