KR100872240B1 - System and method for providing session initiation protocol-based communication service - Google Patents

Abstract

Disclosed is a SIP-based communication service providing system and method thereof. According to an embodiment, regardless of the network structure to which the user terminal belongs, an application of one user terminal may establish a TCP session connection by obtaining IP and port information of the counterpart user terminal through a gateway server. According to the above embodiment, the SIP-supported application mounted on each user terminal consisting of a client terminal and a server terminal uses an gateway server that performs SIP message relay between each application, so that the environment in which the user terminal is placed is an open or closed network. Regardless of recognition, stable TCP session connection can be performed, it can be established at low cost, and TCP session connection can be established with a minimum exchange of signaling information.

Description

SIP-based communication service providing system and method thereof {SYSTEM AND METHOD FOR PROVIDING SESSION INITIATION PROTOCOL-BASED COMMUNICATION SERVICE}

1 is a schematic diagram schematically showing a SIP-based communication service providing system according to an embodiment;

2 is a signal flow diagram illustrating a signal flow when a counterpart user terminal exists in an open network regardless of a network structure of one user terminal through a SIP-based communication service providing system according to an embodiment;

3 is a signal flow diagram illustrating a signal flow when a counterpart user terminal exists in a closed network regardless of a network structure of one user terminal through a SIP-based communication service providing system according to an embodiment;

4 is a signal flow diagram illustrating a signal flow when one user terminal and a counterpart user terminal exist in a closed network through a SIP-based communication service providing system according to an embodiment.

* Description of the symbols for the main parts of the drawings *

2: gateway server 4: register server,

6: proxy server 8: relay server,

10: user terminal A 16: user terminal B

The present invention relates to a SIP-based communication service providing system and method thereof, and more particularly, to allow an application layer of a user terminal to easily establish a TCP session connection through a gateway server without considering the network structure to which the user terminal belongs. The present invention relates to a SIP-based communication service providing system and a method thereof.

In general, the network structure can be largely divided into a closed network and an open network based on the IP allocation method. An open network is a public IP, and all local IPs are public IPs, and there is no restriction in performing communication services with other external shared IPs. A closed network is a network structure with network address translation (NAT) or firewall equipment. In such a closed network, a large number of private IPs use a small amount of public IPs to form a network with the outside. Therefore, a procedure such as IP address translation is required for communication with a closed network. This problem is referred to as a NAT / traversal problem. Here, NAT refers to a network address translator installed at a subscriber end to receive traffic having a public IP, converting the IP address of the received traffic into a private IP of a terminal in the corresponding network, and transmitting the traffic to the corresponding terminal. . A firewall is designed to protect the network from access by unauthorized sources and to ensure that traffic coming from the public network using information of source address, destination address, and traffic type is generated from a trusted device. Allow entry.

Recently, the SIP protocol (Session Initiation Protocol), which has excellent scalability and flexibility in place of H.323 as a protocol for session connection, is widely used. The SIP protocol exists on the UDP / TCP / IP layer. A client / server protocol based on a response method, which allows a session to be started by inviting a communication counterpart. When the communication between the two user terminals is made by the SIP protocol, the application developer needs to consistently implement which of the two user terminals functions as a client and which functions as a server.

Recently, private IP through NAT / firewall equipment is widely used due to lack of public IP and security problems. In the case of a SIP-based communication service for a user terminal connected to such a NAT / firewall equipment, access from such a user terminal to the outside is freely allowed, while there are many restrictions on incoming access from the outside to such a user terminal. This entails cumbersome procedures. In particular, if one or both user terminals belong to a closed network, many complicated procedures are involved in maintaining the consistency of the client / server model between them, exchanging session connection signaling information, exchanging session port information, and so on. Unlike the SIP-based communication, there is a problem that a large cost and time must be consumed in providing a communication service.

Therefore, regardless of whether the user terminal belongs to an open network or otherwise belongs to a closed network with a firewall or a network address translator (NAT) installed, the SIP protocol-based method is simplified by the application layer. There is a need for a technique that enables the formation of a communication session.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described prior art, and regardless of a network structure such as an open network or a closed network, connection information, for example, an IP address and a port, for a terminal to be accessed by an application through a gateway server. It is an object of the present invention to provide a SIP-based communication service providing system and method for easily obtaining a number and the like and establishing a TCP session.

According to an embodiment of the present invention, there is provided a SIP-based communication service providing system including a SIP-based user terminal and a gateway server supporting an application layer and a presentation layer protocol. The gateway server includes a register server that registers the SIP address and URI address of the user terminal, a proxy server that forms a communication session between the user terminals by referring to the register list of the register server, and a closed network environment for both user terminals involved in the communication. If belonging to, includes a relay server that performs a session relay (Session Relay).

According to another embodiment of the present invention, a SIP device by a gateway server that performs session relay or signaling relay for TCP session connection between SIP-based first and second users supporting an application layer and a presentation layer protocol. A half communication service providing method is provided. According to this method, the gateway server receives the INVITE message transmitted from the application layer of the first user terminal and the URI information of the second user terminal, and in advance by the URI information of the second user terminal transmitted from the first user terminal. Retrieve the URI of the registered second user terminal. Then, the INVITE information, the information about the network environment to which the first and second user terminals belong, and the IP and port information of the gateway server are transmitted to the second user terminal. If both network environments to which the first and second user terminals belong are closed network environments, signaling relay is performed between the first and second user terminals connected to the gateway through a TCP session relay in the gateway server, respectively.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram showing a SIP-based communication service providing system according to an embodiment.

As shown, the SIP-based communication service providing system 100 is a server side of the SIP-based gateway server (hereinafter referred to as a gateway server) 2, the user terminal 10 and the user who wants to attempt a mutual session connection It consists of each client side of the terminal 16. The user terminals 10 and 16 each have a protocol of the SIP protocol for transmitting and receiving the necessary information at the application layer through signal encoding / decoding and encryption with the OSI 7 layer, in particular, the application layers 12 and 18 that cover the detailed functions of the user's application. And a representation layer 14, 20. The gateway server 2 uses a presentation layer (not shown) that performs the same role as the SIP presentation layers 14 and 20 in the user terminals 10 and 16, and uses the information processed in the presentation layer. Register server 4, which receives registrations for IP addresses of the application layers 12, 18, proxy server 6 for proxying signaling between application layers 12, 18, and session relaying between applications in a Double NAT environment ( And a relay server 8 that performs a session relay.

In the SIP-based communication service providing system 100, regardless of whether the structure of the network to which each user terminal 10, 16 belongs is open or closed, each application layer 12, 18 through the gateway server (2). It establishes a communication session by obtaining information such as IP address and port number for connection. In particular, according to the SIP-based communication service providing system 100, even if either or both of the user terminal (10, 16) of both sides in the environment belonging to the closed network, the client / server according to such network environment from the standpoint of the application layer It is possible to reduce the developer burden by allowing development to be performed on the premise that the user terminal of the requesting session connection functions as a client without considering the model configuration.

Looking at each component inside the gateway server 2, the register server 4 registers information about the application layers 12, 18 of each user terminal 10, 16, and the proxy server 6 receives SIP. It relays signal transmission. For example, when the gateway server 2 receives the INVITE signal for the user terminal 16 from the user terminal 10, the proxy server 6 refers to the registration list of the register server 4 to thereby the user terminal 16. It is checked whether the application layer 18 is registered, and through this, it is possible to check whether the IP address of the user terminal 16 and the communication network to which the user terminal 16 belongs are a closed network. Then, the proxy server 6 transmits the INVITE signal to the user terminal 16 using the corresponding IP address, at which time the IP address of the gateway server 2 and the port number used are transmitted together. In addition, the proxy server 6 may perform a function of transferring information from the user terminal 16 to the user terminal 10, thereby enabling a communication session to be established between both terminals. The relay server 8 of the gateway server 2 may relay information between applications by performing a session relay function between each user terminal when both user terminals 10 and 16 belong to the closed network.

The register server 4 and the proxy server 6 determine whether both user terminals 10 and 16 participating in the communication session belong to the open network environment or the closed network environment, respectively, Determine whether to establish a session under arbitration or to establish a direct session between the two. Therefore, since this determination is made automatically in accordance with the registration matters in the register server 4, it is not necessary for the user to provide an instruction regarding the network environment of the terminal whenever a communication connection is desired.

Hereinafter, with reference to the accompanying drawings will be described in detail the operation of the SIP-based communication service providing system according to an embodiment of the present invention.

2 illustrates a signal flow when a counterpart user terminal B exists in an open network regardless of a network structure of a user terminal A requesting to establish a session through a SIP-based communication service providing system according to an embodiment of the present invention. Signal flow chart. In Figure 2, UCC_A represents the interface layer (i.e., application layer) of user terminal A and PTC DLL_A is the SIP protocol layer (i.e., presentation layer) for UCC_A, UCC_B is the interface layer of user terminal B and PTC DLL_B Is the SIP protocol layer for UCC_B.

In detail, the UCC_A 22 first establishes a TCP session with the UCC_B 28, and through this function call, a parameter required for the PTC_DLL_A 24 of the UCC_A 22 through a function call to send and receive an IM message. Pass 202. That is, the UCC_A 22 configured in the window-based application layer of the user terminal A transmits port allocation information for the TCP session to the SIP-based PTC_DLL_A 24 of the lower presentation layer.

Then, PTC_DLL_A 24, which is the lower layer of UCC_A 22, mounts URI information (e.g., UCC_B_KEY @ GW_IP) on the counterpart user terminal in the SIP INVITE method to open a TCP session for sending and receiving a requested IM message. The gateway server 2 transmits to the gateway server 2 (204). The INVITE message transmitted from the PTC_DLL_A 24 of the user terminal A to the gateway server 2 includes IP address and port information to be opened for the IM session of the user terminal A, and server daemon port information. . In addition, the INVITE message carries URI information of the counterpart user terminal B and is transmitted. The inclusion of the server daemon port information in the INVITE message sent from the PTC_DLL_A 24 to the gateway server 2 does not know at this point whether the PTC_DLL_A 24 of user terminal A needs to run the server daemon for the TCP connection. Because. The gateway server 2 receiving the INVITE message from the PTC_DLL_A 24 searches whether the UCC_B 28 requested by the UCC_A 22 is registered in the data structure (hereinafter reg_list) of the register server 4 configured therein. If it is registered, find the URI of UCC_B 28 and add the IP address and relay port information of the gateway server 2 to the SIP INVITE message, and send it to PTC_DLL_B 26 of UCC_B 28. (206). At this time, the INVITE message transmitted to the PTC_DLL_B 26 of the UCC_B 28 includes the server daemon port information of the UCC_A 22.

The gateway server 2 can recognize in which network environment the UCC_A 22 and the UCC_B 28 are located (ie, open or closed) through the registration list (reg_list) of the internal register server 4. Will be. For example, if address translation information associated with a public IP of a UCC_B 28 to receive an INVITE signal and a private IP is registered in the register server 4, the gateway server 2 may use the UCC_B 28. You will notice that) is in the NAT environment.

As shown in FIG. 2, when both UCC_A 22 and UCC_B 28 are in an open network rather than in a NAT environment. The gateway server 2 uses the UCC_B 28 to inform that the SIP INVITE message (IP address and port information of the UCC_A, Server Demon Port) and both user terminals 22 and 28 belong to an open network (eg, SDP (A). : Open type, B: open type), and performs a relay of signaling without preparing a TCP relay session through the relay server 8 therein.

When a SIP INVITE message sent through the gateway server 2 is sent to the PTC_DLL_B 26, the PTC_DLL_B 26 immediately rings 180 through the gateway server 2 to the PTC_DLL_A 24 of the UCC_A 22. ) Transmits a response signal (208), and transmits the SIP INVITE message to the UCC_B (210). At this time, the 180 ringing message includes the IP address and port information of the UCC_B (28).

The UCC_B 28 may know that the terminals 22 and 28 of both users exist in the open network through the SDP information transmitted together with the SIP INVITE message. Therefore, it will be appreciated that there is no need to run a separate client daemon to connect a TCP connection to the server daemon of UCC_A 22.

In addition, the PTC_DLL_A 24 of the UCC_A 22 transmits a PRACK (PRE-ACK) signal, which is a temporary response signal to the 180 ringing message, to the PTC_DLL_B 26 of the UCC_B 28 through the gateway server 2 ( 212) The PTC_DLL_B 26 of the UCC_B 28 sends a 200 OK message, which is a response message to the PRACK signal, to the PTC_DLL_A 24 of the UCC_A 22 (214). In this state, when the UCC_B 28 accepts the IM request, the PTC_DLL_B 26 of the UCC_B 28 sends a 200 OK message for the INVITE message to the PTC_DLL_A 24 via the gateway server 2 (216). ). UCC_B 28 then prepares a TCP server socket for the IM.

PTC_DLL_A 24 of user terminal A transmits the IP address and Listening port information of UCC_B 28 to UCC_A 22 (218), and sends an ACK message to PTC_DLL_B 26 via gateway server 2. (220). UCC_A 22 then makes a TCP connection to the IP address and TCP Listening port of UCC_B 28. Through this, a TCP session for IM transmission and reception between the UCC_A 22 and the UCC_B 28 is opened. At this time, the UCC_A 22 requesting the session establishment acts as a client of the TCP session, and the UCC_B 28 receiving the session request acts as a server of the TCP session.

3 illustrates a signal flow when a user terminal A requesting to establish a session exists in an open network and a counterpart user terminal B exists in a closed network through a SIP-based communication service providing system according to an embodiment of the present invention. Signal flow chart.

First, the UCC_A 22 establishes a TCP session with the UCC_B 28 and transmits necessary parameters to the PTC_DLL_A 24 of the UCC_A 22 through a function call in order to send and receive an IM message through the UCC_B 28 (302). ). That is, the UCC_A 22 configured in the window-based application layer of the user terminal A transmits port allocation information for the TCP session to the SIP-based PTC_DLL_A 24 of the lower presentation layer.

Then, PTC_DLL_A 24, which is the lower layer of UCC_A 22, loads the URI information (e.g., UCC_B_KEY @ GW_IP) of the counterpart user terminal in the SIP INVITE method to open a TCP session for transmitting and receiving the requested IM message. Send to server 2 (304). The INVITE message sent from the PTC_DLL_A 24 of the user terminal A to the gateway server 2 includes the IP address and port information to be opened for the IM session of the user terminal A, and a server daemon port for the UCC_A 22. ) Information is included. In addition, the URI information of the user terminal B as the counterpart is mounted on the INVITE message and transmitted. The inclusion of the server daemon port information in the INVITE message sent from the PTC_DLL_A 24 to the gateway server 2 does not know at this point whether the PTC_DLL_A 24 of user terminal A will run the server daemon for the TCP connection. Because.

The gateway server 2 receiving the INVITE message from the PTC_DLL_A 24 searches whether the UCC_B 28 requested by the UCC_A 22 is registered in the data structure (hereinafter reg_list) of the register server 4 configured therein. If it is registered, it finds the URI of UCC_B 28 and adds its own IP and relay port information to the SIP INVITE message and sends it to PTC_DLL_B 26 of UCC_B 28. (306). At this time, the INVITE message transmitted to the PTC_DLL_B 26 of the UCC_B 28 includes the server daemon port of the UCC_A 22.

At this time, the gateway server 2 may recognize in which network environment (open or closed) the UCC_A 22 and the UCC_B 28 are located through the registration list reg_list of the internal register server 4. It becomes possible. As shown in FIG. 3, if UCC_A 22 is placed in an open network that is not in a NAT environment and UCC_B 28 is placed in a closed network of a NAT environment, the gateway server 2 may SIP to UCC_B 28. Sends information about the configuration of both networks with INVITE message, e.g. SDP (A: Open, B: Closed), and only relays signaling without preparing a TCP relay session through the relay server 8 therein. Perform.

When the SIP INVITE message sent through the gateway server 2 is sent to the PTC_DLL_B 26, the PTC_DLL_B 26 immediately sends a 180 ringing response signal via the gateway server 2 to the PTC_DLL_A of the UCC_A 22. In step 308, the UE transmits the SIP INVITE message to the UCC_B 28, in step 310. At this time, the 180 ringing message includes the IP address and port information of the UCC_B (28).

The UCC_B 28 may recognize that the user terminal A, which is the other party, exists in the open network and its terminal exists in the closed network through the SDP information transmitted together with the SIP INVITE message. As such, if the user terminal B receiving the request is placed in a closed network, the external connection from the user terminal B is free while the incoming connection from the outside to the user terminal B is restricted. Accordingly, in this case, the TCP connection is a user who simply functions as a client and receives a request when the user terminals A and B are both present in the open network as shown in FIG. Unlike terminal B functioning as a server so that client TCP client 30 of user terminal A and client TCP server 40 of user terminal B are directly connected, the server daemon 32 of user terminal A is executed to execute a client session ( Client TCP client 30) to operate in conjunction with the IN client daemon 42 and OUT client daemon 44 of user terminal B to execute a server session (client TCP server 40) of user terminal B By connecting and operating. That is, the client TCP server 40 of the user terminal B is connected to the IN client daemon 42 and the IN client daemon 42 is again connected to the OUT client daemon 44. In addition, the OUT client daemon 44 of the user terminal B connects with the server daemon 32 of the user terminal A to form a TCP connection. The server daemon 32 of the user terminal A operates in connection with the client TCP client 30. In short, from the standpoint of UCC_A 22 of user terminal A, it can be seen that the UE itself acts as a client in establishing a TCP session and that the other user terminal B acts as a server, but internally with the server daemon 32 of user terminal A. Communication connections may be made through the respective client daemons 42 and 44 of the user terminal B.

Accordingly, in FIG. 3, the UCC_B 28 that recognizes that the user terminal A, which is the counterpart, exists in the open network and that the user terminal exists in the closed network through SDP information, prepares the client daemons for the TCP session connection. Let's do it.

The PTC_DLL_A 24 of the UCC_A 22 transmits a PRACK (PRE-ACK) signal, which is a temporary response signal to the 180 ringing message, to the PTC_DLL_B 26 of the UCC_B 28 via the gateway server 2 (312). . The PTC_DLL_B 26 of the UCC_B 28 then executes the client daemons 42 and 44 and uses the server daemon port information of the UCC_A 22 contained in the INVITE message to the server daemon 32 of the UCC_A 22. Establish a TCP connection (314). At this time, the client TCP server 40 of the UCC_B 28 makes a TCP connection only to the server daemon 32 of the UCC_A 22 via the IN client daemon 42 and the OUT client daemon 44, and still the UCC_A 22 TCP session connection with the client TCP client 30 is not established.

The PTC_DLL_B 26 of the UCC_B 28 transmits a 200 OK message, which is a response message to the PRACK signal, to the PTC_DLL_A 24 of the UCC_A 22 via the gateway server 2 (316). PTC_DLL_A 24 of user terminal A transmits information necessary for establishing a TCP session to UCC_A 22 (318). The client TCP client 30 of the UCC_A 22 is then connected to the server daemon 32. Since the client TCP server 40 of the UCC_B 28 is already connected with the server daemon 32 of the UCC_A 22, the client TCP server 30 of the UCC_A 22 and the client TCP server of the UCC_B 28 are consequently. A TCP connection of 40 is made. Through this, a TCP session for IM transmission and reception between the UCC_A 22 and the UCC_B 28 is formed.

In the above-described process, the gateway server 2 does not perform relaying of the relay server 8, but only opens ports to relay signaling, and the TCP connection is directly performed between the UCC_A 22 and the UCC_B 28. do.

4 is a signal flow diagram illustrating a signal flow when a user terminal A and a counterpart user terminal B requesting to establish a session exist in a closed network through a SIP-based communication service providing system according to an embodiment of the present invention. In general, the user terminal belonging to the closed network does not directly open a TCP session, but through a TCP session relay by a gateway according to the following procedure.

First, the UCC_A 22 establishes a TCP session with the UCC_B 28 and sends a parameter to the PTC_DLL_A 24 of the UCC_A 22 through a function call in order to send and receive IM messages through the function call. Pass 402. Then, PTC_DLL_A 24, which is the lower layer of UCC_A 22, mounts the URI information (e.g., UCC_B_KEY @ GW_IP) of the counterpart user terminal in the SIP INVITE method to open a TCP session for transmitting and receiving the requested IM message. And transmits to server 2 (404). The INVITE message transmitted from the PTC_DLL_A 24 of the user terminal A to the gateway server 2 includes IP address and port information to be opened for the IM session of the user terminal A and server daemon port information for the UCC_A 22. . Further, the URI information of the counterpart user terminal B is mounted on the INVITE message and transmitted. At this time, the server daemon port information is included in the INVITE message transmitted from the PTC_DLL_A 24 to the gateway server 2 whether the PTC_DLL_A 24 of the user terminal A should execute the server daemon for the TCP connection at this time. Because I do not know.

The gateway server 2 receiving the INVITE message from the PTC_DLL_A 24 searches whether the UCC_B 28 requested by the UCC_A 22 is registered in the data structure (hereinafter reg_list) of the register server 4 configured therein. If it is registered, find the URI of UCC_B 28 and add the IP address and relay port information of the gateway server 2 to the SIP INVITE message, and send it to PTC_DLL_B 26 of UCC_B 28. (406).

The gateway server 2 can recognize in which network environment (open or closed) the UCC_A 22 and the UCC_B 28 are located through the registration list reg_list of the internal register server 4. . As shown in FIG. 4, even when both the UCC_A 22 and the UCC_B 28 are placed in a closed network in a NAT environment, the gateway server 2 may transmit the UCC_B 28 to both sides of the network together with the SIP INVITE message. Information about the configuration of, for example, SDP (A: closed, B: closed) information is transmitted, and the Listening port is opened through the relay server 8 therein to prepare a TCP relay session.

When the SIP INVITE message sent through the gateway server 2 is sent to the PTC_DLL_B 26, the PTC_DLL_B 26 immediately sends a 180 ringing response signal via the gateway server 2 to the PTC_DLL_A of the UCC_A 22. In step 408, the UE transmits the SIP INVITE message to the UCC_B 28 in step 410. The 180 ringing message includes the IP address and port information of the UCC_B 28. The gateway server 2 forwards the corresponding 180 ringing message and the SDP message (SDP (A: closed, B: closed)) to the PTC_DLL_A 24 of the UCC_A 22. Thus, PTC_DLL_A 24 of the UCC_A 22 recognizes that when an accept signal for the INVITE signal is applied, it must directly connect to the relay port of the gateway server 2.

The UCC_B 28 may recognize that the user terminal A, which is the other party, exists in the closed network and its user terminal B also exists in the closed network through the SDP information transmitted together with the SIP INVITE message. As such, if user terminals A and B are present in a closed network, external connections from such user terminals A and B are free, while incoming connections to these user terminals A and B from outside are subject to constraints. Accordingly, in this case, the TCP connection is a user who simply functions as a client and receives a request when the user terminals A and B are both present in the open network as shown in FIG. Unlike terminal B functioning as a server so that client TCP client 30 of user terminal A and client TCP server 40 of user terminal B are directly connected, IN client daemon 42 and OUT client daemon ( 44) by connecting to the server session of the user terminal B (client TCP server 40) to operate. Client TCP server 40 of user terminal B is connected to IN client daemon 42 and IN client daemon 42 is again connected to OUT client daemon 44. The OUT client daemon 44 of user terminal B also establishes a TCP connection to the relay server 8 of the gateway server 2. In the case of user terminal A, the client TCP client 30 is externally connected as a client as the original, but such connection is made to the relay server 8 of the gateway server 2. In short, from the standpoint of UCC_A 22 of user terminal A, it can be seen that the UE itself acts as a client in establishing a TCP session and that the other user terminal B acts as a server, but internally the relay server 8 of the gateway server 2 The communication connection of both user terminals can be made by the relay.

Therefore, in FIG. 4, the UCC_A 22 and the UCC_B 28, which are aware that both user terminals exist in the closed network by the SDP message, respectively, are configured by the relay server 8 configured in the gateway server 2. Connect to the listening port.

Specifically, the PTC_DLL_A 24 of the UCC_A 22 transmits a PRACK (PRE-ACK) signal, which is a temporary response signal for the 180 ringing message, to the PTC_DLL_B 26 of the UCC_B 28 via the gateway server 2. (412). The PTC_DLL_B 26 of the UCC_B 28 then executes the client daemons 42 and 44 to connect to the IP address and port opened by the relay server 8 of the gateway server 2 included in the INVITE message. (414).

The PTC_DLL_B 26 of the UCC_B 28 transmits a 200 OK message, which is a response message to the PRACK signal, to the PTC_DLL_A 24 of the UCC_A 22 via the relay server 8 of the gateway server 2 (416). . The PTC_DLL_A 24 of the user terminal A transmits information necessary for establishing a TCP session to the UCC_A 22 (420). Then, the client TCP client 30 of the UCC_A 22 makes a TCP connection to the relay server 8 of the gateway server 2 by using the IP address and listening port number of the relay server 8. Through this, a TCP session for transmitting and receiving IM messages is established between the UCC_A 22 and the UCC_B 28 through the relay of the relay server 8.

As a result, a TCP session is opened between the UCC_A 22 and the relay server 8, and the relay server 8 and the UCC_B 28, and the relay server 8 of the gateway server 2 moves IM data in either direction. When a message is entered, it acts as a relay to the other side.

According to the present invention, a user who wants to establish a TCP session is already provided by the proxy server 6 and the register server 4 of the gateway server 2 without having to provide information about their network environment at the request of the session establishment. It is determined whether or not the communication connection is to be made through the relay server 8 through the registered information, which can help in establishing a stable session. In particular, when a direct session between peer-to-peer is possible, unnecessary load is prevented from being concentrated on the relay server 8, thereby enabling efficient operation of the server.

On the other hand, according to another embodiment of the present invention, when each application layer 12, 18 is registered in the register server 4, the user can set up all communication connections to be made via the relay server 8 . In such a case, all communication connections initiated by the application layer are made via the relay server 8. According to this embodiment, in case of a connection failure that may occur when attempting a direct connection, for example, when a direct connection is blocked by the firewall setting of the personal PC, it is possible to receive a stable service.

While the invention and its various functional components have been described in particular embodiments, the invention may be implemented in hardware, software, firmware, middleware, or a combination thereof, and the system, subsystem, components or sub-configurations thereof. It should be understood that they can be used as elements. If implemented in software, the elements of the invention are instructions / code segments for performing the necessary tasks. The program or code segments may be stored in a machine readable medium, such as a processor readable medium, a computer program product, or via a transmission medium or communication link by a computer data signal embodied in a carrier wave or a signal modulated by a carrier. Can be sent. Machine readable media or processor readable media may include any medium that can store or transmit information in a form readable and executable by a machine (eg, processor, computer, etc.).

Although the above embodiments have been described with reference to the embodiments shown in the drawings for clarity, this is merely exemplary, and various modifications and equivalent other embodiments are possible to those skilled in the art. I will understand. Therefore, the technical protection scope of the present invention will be defined by the appended claims.

According to the embodiments described herein, the application layer of the user terminal to establish a TCP session by the SIP-based communication service, regardless of whether the network environment to which the user terminal and the counterpart user terminal belongs is open or closed. In other words, it is possible to achieve stable session formation while recognizing itself as acting as a client and acting as a server. In addition, this configuration has the advantage of allowing greater flexibility for application developers.

Claims (9)

A register server for registering a SIP address and a URI address of a SIP-based user terminal, the user terminal supporting an application layer and a presentation layer protocol; A proxy server for establishing a communication session between user terminals with reference to the registration list of the register server; And Gateway server consisting of relay server that performs session relay when both user terminals involved in communication belong to closed network environment SIP-based communication service providing system comprising a. The method of claim 1, The URI information registered in the register server is the SIP-based communication service providing system, characterized in that the IP address and port number of the user terminal. The method of claim 1, When the user terminal generates an INVITE message, the SIP-based communication service providing system, characterized in that for transmitting the IP address and port number, server daemon port number information of the user terminal to the gateway server. The method of claim 1, The gateway server determines whether to open a listening port for session relay of the relay server or to perform TCP session relay for each user terminal based on information of both user terminals involved in the communication. SIP-based communication service providing system characterized in that. The method of claim 1, If the user terminal belonging to the closed network environment receives the INVITE message, the user terminal executes the client daemon to attempt to connect for the TCP session connection, characterized in that the SIP-based communication service providing system. A method for providing a SIP-based communication service by a gateway server for performing session relay or signaling relay for a TCP session connection between SIP-based first and second users supporting an application layer and a presentation layer protocol, Receiving an INVITE message transmitted from an application layer of the first user terminal and URI information of a second user terminal, Retrieving the URI of the second user terminal registered in advance by the URI information of the second user terminal transmitted from the first user terminal, Transmitting the INVITE information, information about a network environment to which the first and second user terminals belong, and IP and port information of the gateway server to the second user terminal, and If the network environment to which the first and second user terminals belong is a closed network environment, signaling relay between the first and second user terminals connected to the gateway through a TCP session relay in the gateway server, respectively. Steps to perform SIP-based communication service providing method comprising a. The method of claim 6, The INVITE message transmitted from the application layer of the first user terminal includes the IP and port information allocated by the first user terminal for the TCP session connection. The method of claim 6, The TCP session relay in the gateway is performed through a session relay server, and a TCP session connection is formed between the first and second user terminals by connecting the first and second user terminals to the session relay server, respectively. SIP based communication service providing method. A computer readable storage medium storing computer executable instructions for performing the method of any one of claims 6 to 8.

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