KR101473588B1 - Call processing system of ims, control method thereof, and recording medium for recording program for executing the control method - Google Patents

Abstract

The present invention relates to a call processing system in an IP multimedia subsystem (IMS) network, a control method thereof, and a recording medium for recording a program for executing the control method. According to the present invention, the method for controlling the call processing system in an IMS network including at least one proxy call session control function (P-CSCF) and at least one serving call session control function (S-CSCF) comprises the following steps of: receiving, by a P-CSCF, a call connection request signal from a terminal, extracting S-CSCF information from the received call connection request signal, and transmitting the call connection request signal to an S-CSCF corresponding to the extracted S-CSCF information; and performing, by the S-CSCF receiving the call connection request from the P-CSCF, a relevant terminal authentication process, and performing a call connection process.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a call processing system of an IMS network, a control method thereof, and a recording medium storing a program for executing the control method,

The present invention relates to a call processing system of an IMS network for enabling an origination call of a corresponding subscriber even in the event of a failure of a P-CSCF having subscriber information of a specific subscriber, a control method thereof, and a program for executing the control method .

IMS (IP Multimedia Subsystem) is a standard for providing multimedia services such as voice, audio, video and data based on Internet Protocol (IP).

The schematic configuration of the components of the IMS network is as shown in FIG. This IMS basically uses general-purpose Internet-based technology and standardized network functions. VoITE (Voice Over Long Term Evolution) service exists as a typical IMS service.

That is, the VoLTE service provides an HD voice call service between VoLTE terminals based on the IMS network.

When a VoLTE terminal accesses an IMS network for VoLTE origination call service, the first node to be connected is a Proxy-Call Session Control Function (P-CSCF), which has subscriber information of the VoLTE terminal in advance, Based on this, the corresponding outgoing call is routed to an appropriate Serving-Call Session Control Function (S-CSCF). The S-CSCF then handles the number translation and supplementary services to deliver outgoing calls to the destination network.

In order for the P-CSCF to have subscriber information of a specific VoLTE terminal, a location registration must be performed from the terminal in advance. The VoLTE terminal informs that it is ready to receive the service through periodic location registration, and the P-CSCF can store the subscriber information of the corresponding terminal in the location registration process.

However, when a P-CSCF node failure occurs, a VoLTE terminal performing location registration through the P-CSCF can not use the VoLTE originating service.

Fig. 2 is a control flowchart for explaining this conventional problem.

When the communication terminal transmits an invite message to a device for performing a kind of load balancing, that is, to the L4 switch, the L4 switch transmits the invite message to the L4 switch by using the information included in the invite signal or the stored information, 1 Invite signal to the P-CSCF (P-CSCF # 1).

In this embodiment, it is assumed that the first P-CSCF is configured to store information that identifies to which S-CSCF the communication terminal should be connected through the location registration process.

If a failure occurs in the first P-CSCF, the L4 switch detects a failure and determines a bypass P-CSCF. For example, if the second P-CSCF (P-CSCF # 2) If so, the L4 switch forwards the Invite signal to its second P-CSCF.

However, since the second P-CSCF receiving the Invite signal does not have the S-CSCF information corresponding to the corresponding communication terminal, it transmits the 404 error message to the communication terminal via the L4 switch.

That is, conventionally, when a failure occurs in the first P-CSCF registered in the location registration process, a normal call connection is not established, so that the communication terminal has to process a call connection failure or go through a new location registration process.

Published Patent No. 10-2006-0113284

SUMMARY OF THE INVENTION The present invention has been conceived to solve the above-mentioned conventional problems, and it is an object of the present invention to provide a P-CSCF for a subscriber, A call processing system of the network, a control method thereof, and a recording medium on which a program for executing the control method is recorded.

In order to achieve the above object, the present invention provides an IP Multimedia Subsystem (IMS) network including at least one Proxy Call Session Control Function (P-CSCF) and at least one Serving Call Session Control Function (S-CSCF) The P-CSCF, which has received the call connection request signal from the terminal of the at least one P-CSCF, extracts the S-CSCF information from the received call connection request signal and transmits the S-CSCF information corresponding to the extracted S- The S-CSCF forwards the call connection request signal to the S-CSCF, and upon receiving the call connection request signal from the P-CSCF among the at least one S-CSCF, performs the corresponding terminal authentication process .

In order to achieve the above object, there is provided an IMS (IP Multimedia Subsystem) including at least one Proxy Call Session Control Function (P-CSCF) and at least one Serving Call Session Control Function (S-CSCF) The control method of the call processing system of the network is characterized in that the P-CSCF, which has received the call connection request signal from the terminal, extracts the S-CSCF information from the received call connection request signal, and transmits the S-CSCF information corresponding to the extracted S- Transmitting a call connection request signal to the mobile terminal; The S-CSCF having received the call connection request signal from the P-CSCF performs a corresponding terminal authentication process and then performs call connection processing.

As described above, according to the present invention, even if a failure occurs in the P-CSCF in which the binding information of the communication terminal is registered in the IMS network, another P-CSCF that does not have the binding information transmits a call connection request The call connection request signal can be transmitted to the S-CSCF (i.e., including the binding information) by using the information included in the signal, thereby increasing the call connection success rate.

1 is a schematic configuration diagram of components of a conventional IMS network,
2 is a control flow diagram of a conventional IMS network element,
3 is a schematic configuration diagram of an entire communication system including a call processing system of an IMS network for explaining an embodiment of the present invention,
4 is a diagram illustrating a process in which a call processing system according to an embodiment of the present invention processes subscriber registration according to a request of a communication terminal,
FIG. 5 is an example of a result response message header transmitted by a communication terminal according to an embodiment of the present invention,
6 is a diagram illustrating a process in which a call processing system according to an embodiment of the present invention performs call processing according to a request of a communication terminal,
7 is a diagram illustrating an example of a call processing request message header transmitted from the communication terminal in FIG.

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

The overall communication system configuration including the call processing system of the IP Multimedia Subsystem (IMS) network 100 according to an embodiment of the present invention is as shown in FIG. In the following description of the present embodiment, unless otherwise stated, each component included in the call processing system of the IMS network can perform functions according to the standards defined by the 3rd Generation Partnership Project (3GPP) have.

1, the communication terminal 200 is a terminal capable of performing communication or data communication by connecting to an IMS network, and corresponds to, for example, a smart phone.

The call processing system includes a Proxy Call Session Control Function (P-CSCF) 110, a Serving Call Session Control Function (S-CSCF) 130, an Interrogating Call Session Control Function (I-CSCF) 140 (Home Subscriber Server).

Hereinafter, a plurality of P-CSCFs 110 and S-CSCFs 130 are provided among the components included in the call processing system.

First, the HSS 140 is a database for storing information required for service control, and is a system for managing subscriber information (location information, authentication information, service information, and the like).

The HSS 140 basically includes or is interoperable with an Authentication Center (AuC) function along with the functionality of a traditional Home Location Register (HLR).

That is, the HSS 140 is a device that performs subscriber mobility management, user authentication information generation, service profile management, account information management, HLR, authentication server, and interworking with an IP-based external service node.

On the other hand, CSCF (Call Session Control Function) is a system that performs SIP call control and session handling functions on an IP network, and provides various multimedia services.

The CSCF may be divided into P-CSCF 110 (Proxy), I-CSCF 120 (Interrogating), and S-CSCF 130 (Serving) according to its functions.

The functions of the P-CSCF 110, the I-CSCF 120, and the S-CSCF 130 will be briefly described below.

First, the P-CSCF 110 is a point where the communication terminal 200 first contacts when accessing the IMS network through access. In other words, it corresponds to the first point where a user (UE: User Equipment) accesses the IMS network. In 3GPP, the UE specifies a method of obtaining the address using the DHCP or the PDP Context for searching the P-CSCF 110 A detailed description thereof will be omitted.

In particular, P-CSCF 110 acts as a proxy or user agent as defined in IETF RFC 2543. CSCF 120 from the communication terminal 200 to the I-CSCF 120 of the home network of the communication terminal 200 and transmits a SIP message from the communication terminal 200 to the S- CSCF 130 to the S-CSCF.

The I-CSCF 120 acts as a point of contact for all calls coming in from the Visited Network to the Home Network, that is, for connecting to subscribers in the network, and as a point of contact with the other subscriber roaming in the network.

The I-CSCF 120 performs a role of forwarding a SIP Request to the S-CSCF 130 and generates billing information. The HSS 140 also determines the HSS 140 by querying the SLF in a network in which the plurality of HSSs 140 are operated. That is, when receiving the SIP REGISTER message, the HSS 140 is selected using the SLF, the address of the S-CSCF 130 is received from the HSS 140, and the S-CSCF 130, .

Lastly, the S-CSCF 130 performs not only all session state management functions of the IMS network but also a subscriber profile in cooperation with the HSS 140 to perform main functions for call processing. That is, the S-CSCF 130 is a subsystem for controlling a session of the UE (communication terminal 200), registers a subscriber in the HSS 140, downloads subscriber information, and stores and manages a service profile do.

Hereinafter, specific functions of the P-CSCF 110 and the S-CSCF 130 according to the present invention will be described.

As described above, there may be a plurality of P-CSCFs 110. The P-CSCFs 110 (hereinafter referred to as " first P-CSCFs 110 ") that have received location registration request signals from the communication terminals 200 among the plurality of P- CSCF 111) controls the S-CSCF 130 to transmit a location registration request signal to any one of the S-CSCFs 130 included in the call processing system of the IMS network, and transmits the location registration request signal to the S- CSCF 130, a location registration success message including the S-CSCF information is transmitted to the communication terminal 200.

At this time, the first P-CSCF 111 may not separately store the S-CSCF information included in the location registration success message. That is, although the first P-CSCF 111 may temporarily store the S-CSCF information for transmission to the communication terminal 200, the first P-CSCF 111 may temporarily store the S-CSCF information in accordance with the call connection request signal of the communication terminal 200, The purpose of selecting the CSCF 130 is not to store the S-CSCF information.

Of course, as another example, the first P-CSCF 111 may store the S-CSCF information for the purpose of selecting the S-CSCF 130. A more detailed description using this will be given later.

Here, the first P-CSCF 111 may control the location registration request signal to be transmitted to any one of the S-CSCFs 130 via the I-CSCF 120.

The P-CSCF 110 may receive a call connection request signal from the communication terminal 200. The P-CSCF 110 receives a call connection request signal from the communication terminal 200 CSCF 112 ') extracts the S-CSCF information from the received call connection request signal and transmits a call connection request signal to the S-CSCF 130 corresponding to the extracted S-CSCF information .

Here, the second P-CSCF 112 may be the same device as the first P-CSCF 111 described above, or may be another device, which will be described later in more detail.

As another example, when the S-CSCF information corresponding to the subscriber of the call connection request signal is stored, the second P-CSCF 112 that has received the call connection request signal from the communication terminal 200 stores the S- CSCF corresponding to the S-CSCF information, and only when the S-CSCF information corresponding to the subscriber of the corresponding call connection request signal is not stored, the S- CSCF information, and then transmit a call connection request signal to the S-CSCF corresponding to the extracted S-CSCF information.

The S-CSCF 130 (hereinafter, referred to as a first S-CSCF 131) that has received the location registration request signal among the plurality of S-CSCFs 130 communicates with the communication terminal 200 in cooperation with the HSS 140, CSCF 111 and transmits a location registration success message including its own information to the first P-CSCF 111 that has transmitted the location registration request signal.

At this time, the first CSCF may control the location registration success message including its own information to be transmitted to the first P-CSCF 111 via the I-CSCF 120. [

In addition, the first S-CSCF 131 receiving the call connection request signal from the second P-CSCF 112 can perform the call connection process after performing the authentication process of the corresponding communication terminal 200. For example, the first S-CSCF 131 registers information of the communication terminal 200 (e.g., telephone number of the communication terminal 200) through the location registration process and transmits the communication included in the call connection request signal The authentication processing can be performed by comparing the information of the terminal 200 with the information of the registered communication terminal 200. If the authentication is successful, the call connection processing can be performed.

CSCF 130 transmits a call connection request signal to the other party when the called party is connected to the other party, and sends a call connection request signal to the I-CSCF 120 when the called party is connected to the internal network. A connection request signal can be transmitted. Since the S-CSCF 130 performs the call connection process in this way, it is a known technology and will not be described in further detail.

Hereinafter, a control flow between each component of the call processing system and the communication terminal 200 according to an embodiment of the present invention will be described with reference to FIG.

When the communication terminal 200 transmits a registration signal to the L4 switch (step S1), the switch L4 is connected to any one of the plurality of P-CSCFs 110 (for example, the load of the P- (Step S3).

In this embodiment, the L4 switch transmits a registration signal to the first P-CSCF 111 as an example.

The first P-CSCF 111 that has received the registration signal of the communication terminal 200 transmits a registration signal to the I-CSCF 120 (step S5) and the I-CSCF 120 transmits the registration signal to the HSS 140 CSCF 130 to transmit the UAR signal and the UAA signal (steps S7 and S9) and to transmit the registration signal. In this embodiment, the first S-CSCF 131 is used as an example.

When the I-CSCF 120 transmits a registration signal to the first S-CSCF 131 (step S11), the first S-CSCF 131 processes subscriber registration (step S13). For example, the first S-CSCF 131 registers the number of the communication terminal 200 so that the user can perform the user authentication process when there is a call connection request from the corresponding communication terminal 200 in the future.

Meanwhile, the first S-CSCF 131 exchanges SAR signals and SAA signals with the HSS 140 (steps S15 and S17), updates the information related to subscriber registration, And may generate binding information that matches the subscriber by acquiring service related information.

4, the first S-CSCF 131 transmits its own information, that is, a subscriber registration success message including "<sip: scscf1.lgt.co.kr; lr> (I.e., a 200 OK message) to the first P-CSCF 111 via the I-CSCF 120 (steps S19 and S21).

An example of the entire subscriber registration success message is as shown in FIG.

Upon receiving the subscriber registration success message from the I-CSCF 120, the first P-CSCF 111 transmits a subscriber registration success message including the first S-CSCF 131 information to the communication terminal 200 (steps S23, S25).

The communication terminal 200 stores the first S-CSCF 131 information included in the Service-route header, that is, the address of the first S-CSCF 131, in the received subscriber registration success message (step S27).

As a result, the communication terminal 200 stores the information of the S-CSCF 130 that processed the subscriber registration.

Hereinafter, a process of transmitting a call connection request signal using the information of the S-CSCF 130 stored in the communication terminal 200 will be described with reference to FIG.

In the present embodiment, it is assumed that a failure has occurred in the first P-CSCF 111 that has processed the registration of the communication terminal 200.

The communication terminal 200 transmits a call connection request signal (i.e., an Invite signal) to the L4 switch, for example, to make a call with the other party (step S31). Here, the Invite signal transmitted from the communication terminal 200 to the L4 switch includes the first S-CSCF 131 information that has been previously stored.

That is, referring to FIG. 6, it can be seen that the first S-CSCF 131 information <sip: scscf1.lgt.co.kr> is included in the Route header. An example of the entire Invite signal transmitted from the communication terminal 200 to the L4 switch is as shown in FIG.

The L4 switch performing the load balancing function determines the detour (step S33), and the other P-CSCF 110 (hereinafter, referred to as the second P-CSCF 111) (Hereinafter referred to as &quot; calling party 112 &quot;) (step S35).

The Invite signal transmitted to the second P-CSCF 112 also includes the first S-CSCF 131 information.

Unlike the first P-CSCF 111, the second P-CSCF 112 does not have subscriber information because it is not involved in the registration process of the communication terminal 200. However, CSCF 131 to the first S-CSCF 131 to which the subscriber is registered by referring to the address of the first S-CSCF 131 (step S39).

That is, according to the conventional method, the information about the first S-CSCF 131 having the subscriber information through the registration process is not included in the Invite signal transmitted by the communication terminal 200, Since the first S-CSCF 112 does not have the first S-CSCF 131 information corresponding to the communication terminal 200, the call connection process fails.

However, even if the first S-CSCF 131 information corresponding to the communication terminal 200 is not stored in the second P-CSCF 112 as in the present embodiment, If the information of the first S-CSCF 131 is included, the second P-CSCF 112 transmits the first S-CSCF 131 information to the first S-CSCF 131 (Step S41).

Since the first S-CSCF 131 stores subscriber information as shown in FIG. 4, the first S-CSCF 131 may transmit an Invite signal after performing an authentication process (step S43).

The subsequent process, that is, the process of connecting the call between the communication terminal 200 and the counterpart terminal corresponds to a known technique, and therefore, a detailed description thereof will be omitted.

Accordingly, when a failure occurs in the first P-CSCF 111 that has been managing the first S-CSCF 131 information corresponding to the communication terminal 200 in the registration process and the second P-CSCF 112 is detoured The second P-CSCF 112 transmits an Invite signal to the first S-CSCF 131 using the first S-CSCF 131 address included in the Invite signal transmitted from the communication terminal 200 So that the success rate of call connection can be increased.

Needless to say, the process of performing each of the above-described embodiments can be performed by a program stored in a predetermined recording medium (for example, a computer readable medium).

The present invention is not limited to the above-described specific embodiments, and various modifications and changes may be made without departing from the gist of the present invention. It is to be understood that such variations and modifications are intended to be included in the scope of the appended claims.

100: IMS network 200: communication terminal
110: P-CSCF 120: I-CSCF
130: S-CSCF 140: HSS

Claims (11)

A control method of a call processing system of an IMS (IP Multimedia Subsystem) network including at least one Proxy Call Session Control Function (P-CSCF) and at least one Serving Call Session Control Function (S-CSCF)
(a) The P-CSCF receiving the call connection request signal from the terminal extracts the S-CSCF information from the received call connection request signal, and transmits a call connection request signal to the S-CSCF corresponding to the extracted S-CSCF information ;
(b) performing a call connection process after the S-CSCF, which has received the call connection request signal from the P-CSCF, performs a corresponding terminal authentication process, and performs call connection processing in the IMS network Way. The method according to claim 1,
Before the step (a)
(c) controlling the P-CSCF, which has received the location registration request signal from the terminal, to transmit a location registration request signal to any one of the S-CSCFs included in the call processing system of the IMS network;
(d) the S-CSCF receiving the location registration request signal processes the location registration of the terminal in association with the HSS (Home Subscriber Server);
(e) After the location registration process is normally performed, the S-CSCF that has processed the location registration of the terminal controls the location registration success message including its own information to be transmitted to the P-CSCF that transmitted the location registration request signal ;
(f) The P-CSCF, which has received the location registration success message, further transmits to the MS a location registration success message including the S-CSCF information to the MS. Method of controlling the system. 3. The method of claim 2,
In step (f), the P-CSCF receiving the location registration success message selects the S-CSCF information included in the location registration success message according to a call connection request signal of the terminal And not stored for use in the IMS network. 3. The method of claim 2,
In step (c), the P-CSCF receiving the location registration request signal controls the location registration request signal to be transmitted to any one of the S-CSCFs via an interrogating call session control function (I-CSCF)
In step (e), the S-CSCF, which has processed the location registration of the MS, transmits a location registration success message including its own information to the P-CSCF that has transmitted the location registration request signal via the I-CSCF And controlling the IMS network according to the control information. The method according to claim 1,
If the S-CSCF information corresponding to the subscriber of the corresponding call connection request signal is stored, the P-CSCF, which has received the call connection request signal from the terminal in step (a), stores the S- CSCF. When the S-CSCF information corresponding to the subscriber of the call connection request signal is not stored, the S-CSCF information is extracted from the received call connection request signal, and the extracted S- CSCF to the S-CSCF corresponding to the CSCF information. A computer-readable recording medium storing a program for executing the method according to any one of claims 1 to 5. 1. A call processing system of an IMS (IP Multimedia Subsystem) network including at least one Proxy Call Session Control Function (P-CSCF) and at least one Serving Call Session Control Function (S-CSCF)
The P-CSCF, which has received the call connection request signal from the terminal of the at least one P-CSCF, extracts the S-CSCF information from the received call connection request signal and transmits the S-CSCF information corresponding to the extracted S- Transmits a connection request signal,
Wherein the S-CSCF, which has received the call connection request signal from the P-CSCF among the at least one S-CSCF, performs a call connection process after performing the corresponding terminal authentication process. 8. The method of claim 7,
Further comprising a Home Subscriber Server (HSS)
The P-CSCF, receiving the location registration request signal from the terminal of the at least one P-CSCF, controls the location registration request signal to be transmitted to any one of the S-CSCFs included in the call processing system of the IMS network, Upon receipt of the location registration success message from the S-CSCF that transmitted the request signal, the S-CSCF transmits a location registration success message including the S-
The S-CSCF, which has received the location registration request signal from the at least one S-CSCF, processes the location registration of the terminal in association with the HSS, and transmits a location registration request signal To the P-CSCF to which the P-CSCF has been transmitted. 9. The method of claim 8,
Upon receiving the location registration success message, the P-CSCF stores the S-CSCF information included in the location registration success message for the purpose of selecting one of the S-CSCFs according to a call connection request signal of the terminal The IMS network comprising: 9. The method of claim 8,
Further comprising an I-CSCF (Interrogating Call Session Control Function)
Upon receiving the location registration request signal, the P-CSCF controls the location registration request signal to be transmitted to any one of the S-CSCFs via the I-CSCF,
Wherein the S-CSCF that has processed the location registration of the MS controls the location registration success message including its own information to be transmitted to the P-CSCF that transmitted the location registration request signal via the I-CSCF Call processing system in IMS network. 8. The method of claim 7,
When receiving the call connection request signal from the MS, the P-CSCF sends a call connection request to the S-CSCF corresponding to the stored S-CSCF information when S-CSCF information corresponding to the subscriber of the call connection request signal is stored When the S-CSCF information corresponding to the subscriber of the call connection request signal is not stored, the S-CSCF information is extracted from the received call connection request signal and the S-CSCF information corresponding to the extracted S- And transmits a call connection request signal to the S-CSCF.

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