KR100899440B1 - Method for providing VoIP service in private network and terminal unit thereof - Google Patents

Abstract

The present invention relates to a method for providing VoIP service in a network using a private address, and a terminal device for implementing the same.

According to the present invention, the originating terminal transmits a session initiation request message by including a first private address allocated from its own private network and a public address mapped to the first private address in a source address.

The called terminal uses the second private address included in the source address of the received session initiation request message and the private network to which the sender who sent the session initiation request message belongs to the private network to which the second private address is mapped. Check if the same. The called terminal transmits the session start response message including the first private address when the calling / called network is the same, and transmits the session start response message including the first public address if it is not the same.

As such, since a session is initiated by identifying whether a network is self or other between the originating / receiving terminals, unnecessary application layer address translation and hairpin operation of the network address translator, which are conventionally performed even in the same network, can be prevented.

 Private network, other network, own network, VoIP service

Description

Method for providing VoIP service in a network using a private address, and a terminal device for implementing the same {Method for providing VoIP service in private network and terminal unit}

1 is a block diagram of a system for providing VoIP service in a network using a private address according to the prior art.

2 is a block diagram of a system for providing VoIP service in a network using a private address according to an embodiment of the present invention.

3 is a flowchart of a method for providing VoIP service in a network using a private address according to an embodiment of the present invention.

4 is a block diagram showing the configuration of a terminal apparatus for providing VoIP service in a network using a private address according to an embodiment of the present invention.

The present invention relates to a method for providing VoIP service in a network using a private address, and a terminal device for implementing the same. More specifically, in a private network using Network Address Translation (hereinafter, referred to as “NAT”), a VoIP service is provided using an Application Layer Gateway (hereinafter, referred to as “ALG”). It relates to a method and a terminal device for implementing the same.

Voice over Internet Protocol (VoIP) is an Internet telephony technology that delivers voice information using the Internet Protocol (hereinafter referred to as "IP"). In VoIP, Session Initiation Protocol (SIP), Media Gateway Control Protocol (MGCF), and H.323 protocol are defined. SIP is a simple, text-based application layer control protocol that allows one or more participants to create / modify / end sessions together.

Most network operators use NAT because of the lack of global IP addresses and the security of their networks. NAT is a technology that converts a private IP address or a port number of Transmission Control Protocol (TCP) / UDP (User Datagram Protocol) into a public IP address or port, respectively, to enable interworking between heterogeneous networks. do.

However, NAT can analyze only Layer 3 (Source IP) and Layer 4 (Source Port) headers of the Open System Interconnection (OSI) model, and does not analyze address information in the Session Description Protocol (SDP).

As described above, since the NAT translation area is limited to the IP layer, a situation in which interworking between heterogeneous networks is impossible when using the SIP protocol for recording address information for actual media transmission in the SDP occurs. This situation is called the problem of “NAT-Traversal”.

ALG technology is the proposed solution to this "NAT-Traversal" problem. ALG technology enables application layer address translation of OSI to enable communication using the SIP protocol between private and public networks.

1 is a block diagram of a system for providing VoIP service in a network using a private address according to the prior art.

According to FIG. 1, the calling terminal 10 and the called terminal 20 are terminals connected to the private network 30, respectively, and the calling terminal 10 checks whether the called terminal 20 belongs to the same network. none. Therefore, the calling terminal 10 assumes that the network to which the called terminal 20 belongs is another network and performs the ALG operation.

That is, the originating terminal 10 receives the information on the public address to be assigned by the network address translator 40 with respect to the private address of the originating terminal 100 from the stun server 50. Stern protocol is a "client-server" protocol based on STUN (Simple Traversal of User Datagram Protocol) through Network Address Translators (NATs).

The calling terminal 10 requests the called terminal 20 to start a session using the public address provided from the stun server 50 as a host address. The called terminal 20 transmits a response to the session start request using the destination address as the public address of the calling terminal 10.

At this time, the network address translator 40 performs routing to a network (not shown) outside the private network since the destination address of the session start response received from the called terminal 20 is a public address. However, since the originating terminal 10 requesting the session initiation exists in the private network, the originating terminal 10 does not receive the session initiation response and the session initiation procedure fails. The failure of the session initiation procedure as described above is called hairpin operation.

Conventionally, when the originating terminal 10 fails to start a session, the calling terminal 10 switches to a turn method and performs session initiation again.

Therefore, a call delay occurs during the failure of the session initiation procedure, the switching to the turn method, and the resumption of session initiation. In addition, using the turn method despite being in the same network is inefficient compared to performing direct transmission / reception between terminals.

Therefore, a technical problem to be achieved by the present invention is to provide a VoIP service in a network using a private address for performing ALG translation after checking whether the originating and terminating terminals exist in the same network, and a terminal apparatus implementing the same. To provide.

VoIP service providing method according to a feature of the present invention in order to achieve the above problems,
A method of providing a VoIP service by a called terminal in a network environment in which a public network using a public address and a private network using each private address interwork through respective network address translators, the first private address assigned to a calling terminal And receiving, from the originating terminal, a session initiation request that includes a first public address mapped to the first private address. The calling terminal and the called terminal are located in the same network by comparing the first private address and the first public address with a second private address assigned by the called terminal and a second public address mapped to the second private address. Checking whether it is; If the same, sending a session start response including the second private address to the calling terminal; And if not the same, transmitting a session start response including the second public address to the calling terminal, wherein the calling terminal includes the second private address in the session start response received from the called terminal. The first private address is used to initiate communication with the called terminal, and when the session initiation response received from the called terminal includes the second public address, the called terminal using the first public address It is characterized in that the communication with the start.

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Terminal device according to a feature of the invention,
A terminal device providing VoIP service in a network environment in which a public network using a public address and a private network using each private address interwork with each network address translator, the first private address allocated from a private network to which the private network belongs And an origination processor for transmitting a session initiation request including a first public address mapped to the first private address to a called party. And a private network to which the private network to which the session initiation request originator belongs is identical to the private network to which the session initiation request originator belongs by using a second private address of the session initiation request originator included in the received session initiation request and a second public address mapped to the second private address. And a call processing unit for transmitting a session start response including the first private address to the session start request sender including the first public address if not the same, and transmitting the session start response including the first public address to the sender. The origination processing unit, when the session initiation response received from the called party includes the private address of the called party, initiates communication with the called party using the first private address and sends the session initiation response received from the called party to the called party. If a public address is included, use the first public address to communicate with the called party. A characterized in that it discloses.

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DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise. In addition, "… part" described in the specification, Module ”means a unit for processing at least one function or operation, which may be implemented as hardware or software or a combination of hardware and software.

Now, a method for providing a VoIP service in a network using a private address according to an embodiment of the present invention and a terminal apparatus implementing the same will be described in detail with reference to the accompanying drawings.

2 is a block diagram of a system for providing VoIP service in a network using a private address according to an embodiment of the present invention.

According to FIG. 2, the VoIP service providing system includes originating / receiving terminals 100 ′ and 100 ″, a private network 200, an application layer gateway server 300, a network address translator 400, and a stun server 500. .

The originating / receiving terminal 100 ', 100 ”may provide a SIP-based VoIP service as a packet-based wired / wireless terminal.

The private network 200 is a network using a private address, and the private network 200 to which the calling terminal 100 'and the called terminal 100 "are connected may be the same or different.

The application layer gateway server 300 is a server that analyzes and converts address information of the application layer of the OSI model that the network address translator 400 does not recognize.

The application layer gateway server 300 is located in the private network 200 and assigned a private address and a static public address. In this case, the application layer gateway server 300 may be the same private network 200 as the originating / receiving terminal 100 ′, 100 ″, or may be different.

The application layer gateway server 300 performs a server function corresponding to the "SIP-client" mounted on the originating and terminating terminals 100 'and 100 ".

The network address translator 400 is a device in which NAT (Network Address Translation) technology is implemented and is located at the boundary of the private network 200 to convert a private address included in a header of a packet into a public address.

The stun server 500 is a server in which a STUN (Simple Traversal of User Datagram Protocol (UDP) through Network Address Translators (NATs)) protocol is implemented. Performs the server function corresponding to “Client”.

Stern server 500 is located outside the network address translator 400 is assigned a public address.

Stern server 500 is a "stern-client" located at the bottom of the network address translator 400 for the existence of the network address translator 400, the type of network address translation and the public address to be assigned by the network address translator 400 Make sure you understand the information.

3 is a flowchart of a method for providing VoIP service in a network using a private address according to an embodiment of the present invention.

According to FIG. 3, each of the calling terminal (100 ′ in FIG. 2) and the called terminal (100 ′ in FIG. 2) has a stun server (500 in FIG. 2), a stun binding request message (STUN), and a stun binding response. Send / receive a message (STUN: Binding Response Message) (S101, S103, S115, S117).

Each of the calling terminal 100 ′ and the called terminal 100 ″ obtains a network address translation type and a mapping address 1 or 2 through stun operations S101, S103, S115, and S117 (S105, S107, S119, and S121). ).

Here, the network address translation type includes a symmetric type and a non-symmetric type. In the symmetric type, the mapping value generated for a specific destination address cannot be used to connect to another destination address. In the asymmetric type, the mapping value generated for one destination address can be used to connect with another destination address.

When the network address translation type is a symmetric type, communication is performed between the originating and terminating terminals 100 'and 100' by packet transmission using a turn (TRA) protocol. The communication process using the turn protocol is omitted because it is not directly related to the embodiment of the present invention.

In addition, the mapping addresses (MA) 1 and 2 are public addresses assigned by the network address translator (400 in FIG. 2) to host addresses (HA) of the originating / receiving terminals 100 'and 100 ”. Means.

Each of the calling terminal 100 ′ and the called terminal 100 ″ checks a connection state with the application layer gateway server 300 (S109 and S123). The connection confirmation is performed by checking connectivity with the application layer gateway server 300 by using each host address assigned in the private network 200 to which it belongs and the mapping address 1 or 2 received in steps S107 and S121. As the inspection method, a method such as ping may be used. Status checks can be made by maintaining a connection using the Transmission Control Protocol (TCP) protocol or through periodic updates using the User Datagram Protocol (UDP).

At this time, each of the calling terminal 100 'and the called terminal 100' may determine whether the application layer gateway server 300 is the same network or another network through the connection state checks S109 and S123.

When the connection with the application layer gateway server 300 is confirmed, each of the calling terminal 100 ′ and the called terminal 100 ″ requests SIP registration (S111, S125) and a response (200) using a register message (Register). OK) is received (S113, S127). In step S111, step S113, step S125, and step S127, each of the calling terminal 100 ′ and the called terminal 100 ″ registers its location information with the application layer gateway server 300.

At this time, the address information of the application layer gateway server 300 is a private address or a public address is used depending on whether the network or other network identified in step S109 and step S123.

In step S105 and step S119, the session connection is made between the calling / calling terminals 100 'and 100 "having confirmed that the network address translation type is an asymmetric type using the mapping addresses 1 and 2 obtained in steps S107 and S121.

First, the originating terminal 100 'transmits an invite message (INVITE) describing the host address, which is a private address allocated from the private network 200 to which the source address belongs, and the mapping address 1 obtained in step S107, to send a session invitation. Request (S129). That is, the host address and the mapping address 1 may be included in the m / c line of the INVITE indicating the source address for media reception.

The application layer gateway server 300 transmits the invite message received in step S129 to the destination terminal 100 ″ (S131).

The called terminal 100 ″ transmits a 180 ringing message to the application layer gateway server 300 (S133), and the application layer gateway server 300 transmits the received 180 ringing message to the calling terminal 100 ′ (S135). .

The called terminal 100 ″ compares the host address and the mapping address 1 of the calling terminal 100 ′ with its host address and the mapping address 2 and determines whether the calling terminal 100 ′ belongs to the same network (S137). ).

As a result, in the case of the same network, the called terminal 100 ″ responds to the session invitation by transmitting a 200 OK message describing its host address in the source address (S139).

The application layer gateway server 300 transmits the 200 OK message received from the called terminal 100 ″ to the calling terminal 100 ′ (S141).

In addition, when the determination result is not the same network, the called terminal 100 ″ responds to the session invitation by transmitting a 200 OK message describing its mapping address 2 to the source address (S143).

In this case, the host address or the mapping address 2 of the called terminal may be recorded in the m / c line indicating the source address for media reception in the 200 OK message.

The application layer gateway server 300 transmits the 200 OK message received from the called terminal 100 ″ to the calling terminal 100 ′ (S145).

Afterwards, real-time media communication between originating / receiving terminals 100 'and 100 "using a host address when belonging to the same private network according to the same network and using mapping addresses 1 and 2 when belonging to different private networks. RTP, Real Time Protocol.

4 is a block diagram showing the configuration of a terminal apparatus for providing VoIP service in a network using a private address according to an embodiment of the present invention. A block diagram showing the configuration of the present invention.

According to FIG. 4, the terminal device 100 includes an address processor 120, a connection processor 140, a session processor 160, and a controller 180.

The address processor 120 performs a "stern-client" function corresponding to the stun server 500 of FIG. 2. That is, the STNC performs communication with the STUN server 500 using the STUN message according to the STUN protocol protocol, requests the network address translation type and the mapping address (1, 2), and receives them.

The access processing unit 140 checks the connection state using the application layer gateway server (300 of FIG. 2) and the mapping address (1, 2) obtained through the host address and the address processing unit 120 allocated from the network to which it belongs. do.

The session processor 160 performs a “SIP client” function corresponding to the application layer gateway server 300. That is, the session is connected with the application layer gateway server 300 by using a Session Initiation Protocol (SIP) message.

The session processing unit 160 includes a registration processing unit 162, an origination processing unit 164, and an incoming processing unit 166 according to detailed functions.

The registration processor 162 performs session access protocol registration for logging in to the application layer gateway server 300.

The call processing unit 164 performs SIP call processing (User Agent Client, UAC) to initialize the SIP request.

The originating processor 164 generates a session initiation request (INVITE) message in which the first host address, which is a private address allocated from the private network to which it belongs, and the mapping address 1 received by the address processor 120, are included in the source address. The session initiation request (INVITE) message is transmitted to the called party through the application layer gateway server 300.

The originating processor 164 receives a session start response (200 OK) message describing the second host address or mapping address 2 allocated in the private network to which the called party belongs according to whether the called party determines the same network.

The originating processor 164 uses the first host address when the source address of the session start response (200 OK) message received from the called party is the second host address, and uses the mapping address 1 when the source address is the mapping address 2. SIP-based real-time media communication with the called party.

The incoming processing unit 166 performs SIP incoming processing (User Agent Server, UAS) that receives a SIP request and returns a response thereto.

The incoming processing unit 166 checks the source address of the session initiation request (INVITE) message received from the calling party through the application layer gateway server 300 to determine whether the same network as the calling party. In this case, the determination is performed by comparing the second host address and mapping address 2 allocated in the private network to which the calling party is included in the source address of the session initiation request (INVITE) message with the first host address and mapping address 1 allocated in the private network to which the originating party belongs. do.

The destination processing unit 166 according to the determination result of the same network, the session initiation response (200 OK) message having the first host address as the source network and its mapping address 1 as the source address if it is not the same network as the calling party. It generates and transmits to the calling party through the application layer gateway server (300).

The incoming processing unit 166 performs real-time media communication based on the session access protocol using the first host address or the mapping address 1 according to the address included in the source address of the transmitted session start response (200 OK) message. .

The controller 180 is connected to the address processor 120, the connection processor 140, and the session processor 160 to control their operations.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

As described above, according to the embodiment of the present invention, since the session is initiated by identifying whether or not the self network or the other network is between the originating and terminating terminals, it is possible to prevent unnecessary application layer address translation, which is conventionally performed even in the same network.

In addition, the problem of call delay caused by resuming session initiation using a turn protocol due to the failure of media reception due to the conventional hairpin operation is not possible.

Claims (11)

In a method in which a called terminal provides VoIP service in a network environment in which a public network using a public address and a private network using each private address interwork with each network address translator, Receiving a session initiation request from the originating terminal, the session initiation request including a first private address assigned to the originating terminal and a first public address mapped to the first private address; The calling terminal and the called terminal are located in the same network by comparing the first private address and the first public address with a second private address assigned by the called terminal and a second public address mapped to the second private address. Checking whether it is; If the same, sending a session start response including the second private address to the calling terminal; If not the same, transmitting a session start response including the second public address to the calling terminal, The originating terminal initiates communication with the called terminal using the first private address when the session initiation response received from the called terminal includes the second private address, and the session start response received from the called terminal. If the second public address is included in the VoIP service providing method characterized in that to communicate with the called terminal using the first public address. The method of claim 1, After transmitting the session start response including the second public address to the calling terminal, If the calling terminal and the called terminal are the same according to whether or not the same network, the second private address is used, and if not the same using the second public address, the called terminal is based on the session access protocol based on the calling terminal To perform real-time media communications of VoIP service providing method comprising more. The method according to claim 1 or 2, The called terminal, The originating terminal is logged in to an application layer gateway server performing address translation of the logged in application layer, and receives a message for the session initiation request from the originating terminal by performing a proxy function of the application layer gateway server and responding to the session initiation. VoIP service providing method for transmitting a message for the calling terminal. The method according to claim 1 or 2, The called terminal, VoIP that the calling terminal receives the first public address obtained through communication with a public address information providing server connected to the network address translator and obtains the second public address through communication with the public address information providing server How we deliver the service. The method according to claim 1 or 2, The receiving step, When the calling terminal checks the type of the network address translator from the public address information providing server connected to the network address translator, the first private address and the first public address are included in the address for media reception in the case of the asymmetric type. VoIP service providing method for receiving the session start request message. In a terminal device providing a VoIP service in a network environment where a public network using a public address and a private network using each private address interwork with each network address translator, An originating processor for transmitting a session start request including a first private address allocated from a private network to which the network belongs and a first public address mapped to the first private address; And Whether the private network to which the session initiation request sender belongs and the private network to which the session initiation request originator belongs is identical are identified using the second private address of the session initiation request sender included in the received session initiation request and a second public address mapped to the second private address. A call processing unit for determining, if it is the same, transmitting a session start response including the first private address, and if it is not the same, sending a session start response including the first public address to the session start request sender; The origination processing unit, when the session initiation response received from the called party includes the private address of the called party, initiates communication with the called party using the first private address and sends the session initiation response received from the called party to the called party. If the public address is included, the terminal device, characterized in that for communicating with the called party using the first public address. The method of claim 6, An application layer gateway server that performs the proxy function of the session access protocol that delivers the message requesting session initiation and the message responding to the session initiation request, where the application layer gateway server is the server that performs the address translation of the application layer. Connection processing unit for managing connection status Terminal device further comprising. The method of claim 7, wherein An address processing unit for communicating with a public address information providing server connected to the network address translator for obtaining the first private address and the first public address; Terminal device further comprising. The method of claim 8, The outgoing processing unit, When the type of the network address translator is confirmed from the public address information providing server through the address processing unit, in case of an asymmetric type, a session initiation request including the first private address and the first public address as a source address for media reception; Terminal device for transmitting a message. The method according to any one of claims 6 to 9, The outgoing processing unit, If the source address of the called party included in the session start response received from the called party is a private address, the first private address is used; if the called party is a public address, the session access protocol is based on the session access protocol with the called party. Terminal for performing real-time media communication of the. The method according to any one of claims 6 to 9, The incoming processing unit, The first private address is used if the private network to which the session initiation request sender belongs is identical to the private network to which the session initiation request sender belongs. Terminal device for performing protocol-based real-time media communication.

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