KR101074208B1 - System for providing call service based SIP supporting NAT/firewall device and method thereof - Google Patents

Abstract

The present invention relates to a technology for providing a SIP-based communication service by applying a device having a proxy function of SIP signaling and media to customers using the existing NAT / firewall equipment.

To this end, the present invention is the first process of registering the IP address and port number of the SIP terminal using the private IP address and the port number is changed to the soft switch; When the SIP signal message for the called party is transmitted from the SIP terminal (calling SIP terminal), the originating proxy changes and registers the IP address and port number of the calling SIP terminal registered in the SIP message, and sends the call. A second step of transmitting, to the soft switch, a SIP signal message in which the IP address and the port number of the SIP terminal of the second side are registered; And a third process of the soft switch transmitting the SIP signal message to the called party and establishing a media connection for providing a SIP call service between the SIP terminal and the called SIP terminal.

Description

System and providing call service based SIP supporting NAT / firewall device and method supporting NAT / Firewall equipment

1 is a diagram illustrating a network configuration to which a SIP-based communication service providing method for supporting NAT / firewall equipment according to an embodiment of the present invention is applied.

2 is a signal flow diagram illustrating a SIP terminal registration procedure applied to a method for providing a SIP-based communication service supporting NAT / firewall equipment according to an embodiment of the present invention.

3 is a signal flow diagram illustrating a SIP-based communication service providing method for supporting NAT / firewall equipment according to an embodiment of the present invention.

The present invention relates to a SIP-based communication service providing system and method for supporting NAT / firewall equipment, and more specifically, SIP by applying equipment having a proxy function of SIP signaling and media to customers using existing NAT / firewall equipment. The present invention relates to a technology for providing a base communication service.

Subscribers are using NAT / firewall equipment due to lack of public IP or security.

On the other hand, the firewall is to protect the network from access by unauthorized sources and to block traffic using information of source address, destination address and traffic type. Only allow entry. However, SIP-based call services are intended to receive calls from unspecified multiple terminals, which receive media from the dynamically assigned ports of unspecified counterpart SIP terminals, which can induce traffic ingress to specific IPs and ports. Contrary to the policy of disallowing or permitting firewalls, it is difficult for most operators to expect to change the firewall's filtering policy for SIP-based call services.

And, due to lack of public IP, a lot of private IPs are used by using NAT (Network Address Translation) equipment. In order to send and receive call signals for calls from SIP terminals connected to these NAT equipments, private IP is added to SIP-based call signal messages. By setting the port number and to create a media flow that can transmit and receive the actual audio and video data. If the IPs exchanged with each other are private IPs, data is sent by setting a destination address for media transmission as a private IP, but the data set as a private IP cannot be routed in the public network. For reference, NAT is a terminal installed in the subscriber station, receives the traffic having a public IP, performs a function of changing the IP address of the received traffic to transmit to the SIP terminal having a private IP.

This problem is called NAT / Traversal problem, and the IETF standardization body proposes some solutions. The method proposed by the standardization organization is to upgrade or replace existing NAT / Firewall equipment, and to install a client program for a solution in an existing SIP terminal.

However, this method is inconvenient for customers because of the additional costs incurred by upgrading or replacing existing NAT / Firewall equipment, inefficient efficiency for existing NAT / Firewall equipment, and the need to load client programs on existing SIP terminals. There is a problem that causes.

In this case, the user of the SIP terminal should be actively loaded with the client program, but if the client program is not mounted on the SIP terminal due to the user's inadequate operation or lack of publicity, the SIP terminal user still cannot use the SIP-based call service. do.

The present invention, which was created to solve the above problems, aims to provide a SIP-based communication service by applying equipment having a proxy function of SIP signaling and media to customers using existing NAT / firewall equipment.

SIP-based communication service providing system for supporting NAT / firewall equipment according to the present invention for realizing the above object, SIP terminals using a SIP voice call service using a private IP address and port number; A proxy for changing the private IP address and the port number of the SIP terminal into a public IP address when receiving a registration signal message for a voice call from the SIP terminal; And a soft switch for processing a SIP signal message so that a voice call connection between the SIP terminal registered with the public IP address and a port number is established via the proxy.
In addition, the SIP-based communication service providing method for supporting NAT / firewall equipment to achieve the above object, the soft switch by changing the IP address of the SIP terminal using the private IP address and port number to its own IP address First course to register for; When the originating proxy among the proxies receives the SIP signaling message for the called voice call from the calling SIP terminal among the SIP terminals, the IP address of the calling SIP terminal is changed to the own IP address in the SIP signaling message. Registering and transmitting the SIP signal message to the soft switch; A third step of the soft switch querying the called party proxy IP information corresponding to the telephone number of the called SIP terminal stored in the SIP signal message and transmitting the SIP signal message to the called party proxy; And a fourth process of checking the private IP address of the called SIP terminal stored in advance by the called party proxy and transmitting the SIP signal message for the voice call to the identified private IP address.

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

1 is a diagram illustrating a network configuration to which a SIP-based communication service providing method supporting NAT / firewall equipment according to an embodiment of the present invention is applied.

In Fig. 1, reference numeral 101 denotes an outgoing SIP terminal for calling the incoming SIP terminal 111 based on the SIP, and 102 registers the outgoing SIP terminal 101 with the soft switch 103, from the outgoing SIP terminal 101. It is the originating proxy that enables the transmitted traffic to be delivered to the destination SIP terminal 111 with a specific private IP and port number.

Reference numeral 111 is an incoming SIP terminal called by the originating SIP terminal 101 based on the SIP, and 112 is a traffic transmitted from the originating SIP terminal 101 by registering the terminating SIP terminal 111 with the soft switch 103. Is a called-side proxy for delivering to the called SIP terminal 111.

Reference numeral 103 generates a subscriber profile for the originating SIP terminal 101 in association with the originating proxy 102, registers the originating SIP terminal 101, and works with the called side proxy 102 for the destination SIP terminal 101. A soft switch that registers the called SIP terminal 101 by creating a subscriber profile for the call and transmits the traffic transmitted from the calling SIP terminal 101 to the called party proxy 112 using the subscriber profile. to be.

Hereinafter, a SIP terminal registration process applied to a SIP-based communication service providing method supporting NAT / firewall equipment according to an embodiment of the present invention will be described in detail with reference to the signal flow diagram shown in FIG. 2.

When the originating SIP terminal 101 sets the IP information (192.168.1.2) of the originating SIP terminal in the SDP-based REGISTER signal message to register the terminal and transmits it to the originating proxy 102 (S2), the originating proxy ( 102, after changing the IP (192.168.1.2) of the outgoing SIP terminal 101 set in the received SDP-based REGISTER signal message to its IP (147.6.6.1) (S4), the IP address is changed to the REGISTER signal message Is transmitted to the soft switch 103 (S6). Here, the proxy IP (147.6.6.1) is a public IP that can be routed in NAT.                     

The soft switch 103 receives the REGISTER signal message changed to the proxy IP, generates a subscriber profile with information such as a phone number, subscriber ID, and proxy IP included in the REGISTER signal message (S8), indicating normal registration completion. The 200 OK signal message is transmitted to the calling party's proxy 102 (S10).

The originating proxy 102 receiving the 200 OK signal message generates the terminal connection information with the phone number and the terminal IP information (S12), and transmits the 200 OK signal message to the calling SIP terminal 101 (S14).

Through the series of procedures described above, the originating SIP terminal 101 is registered with the soft switch 103 with the IP address of the originating proxy 102.

Although the procedure for registering the soft switch 103 of the originating SIP terminal 101 has been described with reference to FIG. 2, the destination IP terminal 101 also performs the same procedure as described above in S2 to S20, and the soft switch 103 is called. By registering with the IP address of the side proxy 112, the subscriber profile is created in the soft switch 103.

Through the above procedure, the SIP terminals 101 and 1111 registered in the soft switch 103 using the IP addresses of the proxies 102 and 112 may receive a SIP-based communication service.

Next, a SIP-based communication service providing method supporting NAT / firewall equipment according to an embodiment of the present invention will be described in detail with reference to the signal flow diagram shown in FIG. 3.

When the originating SIP terminal 101 to use the SIP-based communication service transmits the SDP based INVITE signal message set to its private IP (192.168.1.2) address and port number 2424 to the originating proxy 102 ( S30), the originating proxy 102 changes the terminal IP information and the port number to its public IP (147.6.60.1) and the port number 4242 in the received INVITE message (S32) to the soft switch 103. Transmit (S34).

Accordingly, the soft switch 103 searches the subscriber profile by the called party number set in the INVITE signal message, checks the IP address of the called party proxy 102 (S36), and receives the INVITE signal message from the called party proxy 102. Send to. Here, since the IP address and the port number of the called party's proxy 102 are registered in the subscriber profile corresponding to the called party's phone number, the soft switch 103 is the called party's phone number. The IP address of 102 can be checked.

Subsequently, the called party proxy 112 searches for the terminal connection information generated during the registration process, checks the private IP address of the called SIP terminal, and then delivers the INVITE signal message to the confirmed private IP address (S40). At this time, since the source IP address included in the INVITE signal message is changed to the public IP address of the source proxy 102, the IP address of the originating SIP terminal 111 passes through a firewall allowing only traffic transmitted from a specific IP address. It can pass traffic and traverse NAT, which can only route traffic from public IP addresses. For this reason, SIP-based communication services can be provided to SIP terminal customers using firewalls or NAT equipment.

Meanwhile, when the called SIP terminal 111 is hooked off, the called SIP terminal 111 sets the private IP address (192.168.1.5) and the port number 2626 of the called terminal to the SDP based 200. It registers the OK signal message and transmits it to the called party's proxy 112 (S42).                     

The destination proxy 112 changes the private IP address and port number of the terminal registered in the SDP based 200 OK signal message to its public IP address (147.6.62.2) and port number 6242 (S44). The 200 OK signal message with the changed address and port number is transmitted to the soft switch 103 (S46).

Accordingly, the soft switch 103 transmits a 200 OK signal message to the calling proxy 102 to notify that the call is established to the calling proxy 102 (S48), and the calling proxy 102 also sends the calling SIP terminal to the calling SIP terminal. The SDP based 200 OK signal is transmitted to notify that the call is established (S50).

As a result, a media connection is established between the calling SIP terminal 101 and the calling proxy 102, and a media connection is established between the calling proxy 102 and the called proxy 112, and the called proxy 112 and the called party are connected. Media connection between the SIP terminal 111 is established, it is possible to provide a SIP-based call service between the originating SIP terminal 101 and the destination SIP terminal 111.

In the present invention, since the calling SIP terminal 101 and the called SIP terminal 111 communicate using the IP addresses and port numbers of the calling proxy 102 and the called proxy 112, respectively, it is necessary to use a firewall or NAT. It is possible to provide SIP-based call service regardless.

As described above, according to the SIP-based communication service providing system and method for supporting NAT / firewall equipment according to an embodiment of the present invention, the subscriber using the existing NAT or firewall equipment additional upgrade due to the replacement of the existing equipment SIP-based call service can be provided at no cost.

In addition, according to the present invention, since the service provider can expand the application target of the SIP-based call service, it is possible to continuously provide new additional services based on the revenue generation and the basic call service, which is expected to generate new revenue. It can be effective.

On the other hand, the present invention is not limited to the above-described embodiment, but can be modified and modified within the scope not departing from the gist of the present invention, such modifications and changes should be regarded as belonging to the following claims. will be.

Claims (12)

SIP terminals using a SIP voice call service using a private IP address and a port number; A proxy for changing the private IP address and the port number of the SIP terminal into a public IP address and receiving the registration signal message for the voice call from the SIP terminal; SIP-based communication supporting NAT / firewall equipment, characterized in that it comprises a soft switch for processing a SIP signal message so that the voice call connection between the SIP terminal registered by the public IP address and the port number is set via the proxy. Service delivery system. The method of claim 1, wherein the proxy is It is installed between the SIP terminal and the soft switch, generates connection information of the SIP terminal, changes the IP address and port number registered in the SIP signal message generated from the SIP terminal, and transmits to the soft switch, SIP-based communication service providing system for supporting NAT / firewall equipment, characterized in that for transmitting the SIP signal message transmitted from the soft switch to the corresponding SIP terminal. 3. The proxy of claim 2 wherein the proxy is SIP-based communication service providing system for supporting NAT / firewall equipment, characterized in that for changing the IP address and port number registered in the SIP signal message transmitted from the SIP terminal to its public IP address and port number. The method of claim 3, wherein the public IP address and the port number SIP-based communication service providing system for supporting NAT / firewall equipment, characterized in that the target allowed to the firewall used by the SIP terminal. The soft switch according to any one of claims 1 to 3, wherein Based on the SIP signaling message (REGISTER) transmitted from the proxy to support the NAT / firewall equipment, characterized in that the subscriber profile that registers the IP address and port number of the SIP terminal as the public IP address and port number of the proxy SIP-based communication service providing system. A first step of the proxy changing the IP address of the SIP terminal using the private IP address and the port number to its own IP address and registering it in the soft switch; When the originating proxy among the proxies receives the SIP signaling message for the called voice call from the calling SIP terminal among the SIP terminals, the IP address of the calling SIP terminal is changed to the own IP address in the SIP signaling message. Registering and transmitting the SIP signal message to the soft switch; A third step of the soft switch querying the called party proxy IP information corresponding to the telephone number of the called SIP terminal stored in the SIP signal message and transmitting the SIP signal message to the called party proxy; A fourth process of confirming the private IP address of the called SIP terminal stored in advance by the called party proxy and transmitting the SIP signal message for a voice call to the confirmed private IP address; SIP-based communication service providing method for supporting NAT / firewall equipment, characterized in that it comprises a. The method of claim 6, wherein the first process is A step 1-1 of the SIP terminal transmitting a REGISTER message registered with a private IP address and a port number to the proxy; A first step 1-2 in which the proxy changes and registers the private IP address and port number registered in the REGISTER message to its public IP address and port number; A first to third step of transmitting a register message of the changed registered IP address and a port number to the soft switch; Generating a subscriber profile for the SIP terminal by using the soft switch, the public IP address and the port number, and then transmitting a 200 OK message to the SIP terminal; Steps 1-5 of transmitting the 200 OK message to the proxy; The proxy generates a connection information for the SIP terminal, and the SIP-based communication service providing method for supporting NAT / firewall equipment, characterized in that it comprises a step 1-6 of transmitting the 200 OK message to the SIP terminal. . The method of claim 6, wherein SIP-based communication service providing method for supporting the NAT / firewall equipment, characterized in that the IP address and port number of the SIP terminal is registered and changed to the public IP address and port number of the proxy. 8. The method according to claim 6 or 7, The third process is The soft switch queries the called party's subscriber profile, and transmits the SIP signaling message to the inquired public IP address and port number; The fourth process, Step 4-1 of receiving, by the called party proxy of the public IP address and the port number, receiving the SIP signal message and inquiring about SIP terminal connection information; A step 4-2 of transmitting the SIP signal message to a called SIP terminal having a private IP address and a port number based on the inquiry result; Step 4-3 in which a 200 OK message transmitted from the called SIP terminal is sent to the soft switch via the called proxy; Step 4-4 of the soft switch transmitting the 200 OK message to the originating proxy; And And a 4-5 process of the originating proxy inquiring the connection information and transmitting the 200 OK message to the calling SIP terminal. 10. The method of claim 9, wherein The called proxy may change a private IP address and a port number of the called SIP terminal into a public IP address and a port number, and transmit a 200 OK message in which the IP address and the port number are changed to the soft switch. SIP-based communication service providing method that supports / firewall equipment. 11. The method according to any one of claims 7 to 10, wherein the public IP address and port number are SIP-based communication service providing method for supporting a NAT / firewall equipment, characterized in that the allowed object is specified in the firewall used by the SIP terminal. 10. The method of claim 9, wherein the media connection is SIP-based supporting NAT / Firewall equipment, characterized in that configured between the calling SIP terminal and the calling proxy time, the calling proxy and the called proxy time, and between the called proxy and the called SIP terminal. How to provide communication service.

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