KR101015742B1 - A method for selecting a serving call session control function according to a function of a terminal in an IP-based multimedia subsystem - Google Patents

Abstract

The present invention relates to a method for selecting an S-CSCF by an I-CSCF in an IP-based multimedia subsystem network, comprising: receiving host information and performance information of the S-CSCF by an operator command; A process of configuring a management database including a process, a process of configuring a performance DB for establishing a relationship between serving performance and the S-CSCF by using the management database, and the management DB using performance information of a terminal requiring registration; And selecting the S-CSCF supporting the performance of the terminal by searching the performance DB, wherein the I-CSCF configures S-CSCF information for selecting the S-CSCF and determines a relationship according to serving performance. By setting the S-CSCF based on the above information, there is an advantage that can be effectively used when implementing the IMS network.

IMS, I-CSCF, S-CSCF, HSS, SAA, SAR

Description

A method for selecting a serving call session control function according to the function of a terminal in an IP-based multimedia subsystem network             

1 illustrates the components and interfaces of an IM CN subsystem in an ALL IP core network architecture.

2 is a diagram illustrating a procedure for selecting an S-CSCF in an I-CSCF according to a preferred embodiment of the present invention.

3 is a flowchart illustrating a database configuration procedure of S-CSCF information according to a preferred embodiment of the present invention.

4A-4B are flow diagrams illustrating a flow for selecting an S-CSCF in an I-CSCF in accordance with a preferred embodiment of the present invention.

The present invention relates to an IP-based subsystem (hereinafter referred to as "IMS") network. In particular, an interrogating-call session control function (hereinafter referred to as "I-CSCF") is provided. The present invention relates to a method of selecting a serving-call session control function (hereinafter, referred to as 'S-CSCF').

Recently, with the rapid development of mobile communication and the Internet, it is required to realize various multimedia services of high quality for mobile subscribers. The development of the Internet multimedia service required a change from the existing circuit-based next generation core network (hereinafter referred to as 'CN') to the packet-based CN, and further, the IP-based ( Evolving to IP-based CN form. Currently, 3GPP (3Generation Partnership Project) standardizes all IP-based network reference models to provide IM (IP-based Multimedia) services.

The IM service refers to a service capable of simultaneously providing various types of packet-based services based on an IP transport protocol to a mobile subscriber at a lower level. Of course, you can use non-real-time services such as file transfer, e-mail, and short messages at the same time, or use new services such as videophones, instant messaging, emergency calls, etc. ), Local service, presence service, etc. are available.

1 is a diagram illustrating components and interfaces of an IMS network in an ALL IP core network structure.

Referring to FIG. 1, an IM service domain is a call session control function (hereinafter referred to as a 'CSCF') that is responsible for registration and multimedia call processing using a SIP (Session Initiation Protocol) protocol. 140, 150), and a home subscriber server incorporating functions for mobility management and authentication of an IP multimedia user in a home location register (HLR) function of a legacy mobile network (hereinafter, referred to as HLR). Home Subscriber Server, hereinafter referred to as 'HSS'. Let's take a closer look at the signaling protocol and session procedures between CSCF and HSS, which are important factors for IM service, and related functional elements.

Since the CSCFs 120, 140, and 150 perform different functions depending on the network in which the subscriber is located, the Proxy-CSCF (P-CSCF) 120 and the Interrogating CSCF (I-CSCF) are based on their location and role. 140 may be logically divided into a Serving CSCF (S-CSCF) 150.

The P-CSCF 120 is the first point of contact of the user equipment (hereinafter referred to as 'UE') 110 to the IM multimedia network 100 and is present in the same domain as the Gateway GPRS Support Node (GGSN). do. The P-CSCF 120 transfers the SIP registration request message received from the UE to the I-CSCF 140 with reference to the home domain of the UE, and the S-CSCF received the SIP message received from the UE through a registration procedure. The address is transmitted to the S-CSCF 150 using the address. In addition, the UE 110 functions to request or respond to a SIP message.

I-CSCF 140 is the first point of access to the home network of the UE (110) may exist several in one network domain. The I-CSCF 140 receives the address of the S-CSCF that performs SIP registration of the UE 110 from the HSS 130 and then selects the S-CSCF 150 that is in charge of the actual registration or receives it from another network. One SIP message is routed to the S-CSCF 150.

The S-CSCF 150 registers the session control server of the UE 110 with the HSS 130, downloads and stores subscriber information of the UE 110, and manages the session state of the registered UE 110. It provides information related to (tone, announcement). Obtain the address of the I-CSCF of the home domain of the destination UE through the dialed number of the UE 110 or the SIP URL, and perform authentication with the authentication information received from the HSS 130 at the time of registration of the UE 110. . It can also perform the function of P-CSCF.

Since the I-CSCF does not describe a method for selecting an S-CSCF in the conventional IMS network as described above, there is no specific method for the I-CSCF to select one of several S-CSCFs when implementing the IMS network. There was a problem.

Accordingly, an object of the present invention, which was created to solve the problems of the prior art operating as described above, is to provide an information construction method necessary for the I-CSCF to select an S-CSCF that satisfies the serving capability of the UE. To provide.

Another object of the present invention is to provide an operation method for selecting an S-CSCF that simultaneously satisfies the essential performance and the selective performance of the UE.

In order to achieve the above object, an embodiment of the present invention provides a method for selecting an S-CSCF by an I-CSCF in an IMS network. Receiving an input, configuring a management database including the input information, configuring a performance DB for establishing a relationship between serving performance and the S-CSCF using the management database, and registering And searching for the management DB and the performance DB by using the capability information of the terminal, selecting the S-CSCF supporting the capability of the terminal.

Hereinafter, the operating principle of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily flow the gist of the present invention, the detailed description thereof will be omitted. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

The present invention described below will specifically describe a preferred embodiment of the present invention with respect to the selection method of S-CSCF in the IMS network.

First, a method of configuring information of the S-CSCF in the I-CSCF system will be described. The IMS network includes several types of CSCFs, and when the UE connects to the service, it connects to the I-CSCF via the P-CSCF and selects one of the plurality of S-CSCFs to perform subscriber information and control services. In the I-CSCF, host information (realm and IP address) and performance information of the S-CSCF are input by an operator command. Table 1 below shows an example of host information and performance information of the S-CSCF.

As shown in Table 1, there are two S-CSCFs, SCSCF1.SEC.COM and SCSCF2.SEC.COM, connected to the I-CSCF, and each S-CSCF information includes, for example, an IP address and a service type. Or location information. The I-CSCF uses the S-CSCF information input as shown in Table 1 to configure two types of databases (Database, hereinafter referred to as 'DB').

Table 2 below shows a DB (hereinafter referred to as 'S-CSCF management DB') for managing serving performance supported by S-CSCF.

In Table 2, the index value is automatically assigned when the I-CSCF system stores the S-CSCF information, the host name of the S-CSCF is described for each index, and the IP address is described as necessary. Is possible. And a bit array indicating the supportable performance of each S-CSCF.

After configuring the management DB of Table 2, a DB (hereinafter, referred to as an 'S-CSCF performance DB') representing a relationship between serving performance and S-CSCF is configured as shown in Table 3 below.

As shown in Table 3, the index value of the S-CSCF is managed in bit form. This is to perform an AND operation when searching for S-CSCFs satisfying a plurality of performances. The bits of the S-CSCF List Value are S-CSCF 0,1,2,3... Corresponds to. For example, performance value 1 supports only S-CSCF 1, so the S-CSCF list value of performance 1 becomes 2 ('0010'), and performance value 2 supports S-CSCF 1,2. S-CSCF list value 0 ('0000') of performance value 2 means that there is no delayable S-CSCF. The S-CSCF list value is 6 ('0110').

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

2 is a diagram illustrating a procedure for selecting an S-CSCF in an I-CSCF according to a preferred embodiment of the present invention.

The UE, not shown, connects to the P-CSCF and transmits a register message to the I-CSCF 301 through the P-CSCF in step 310. The register message includes a Call-ID Header value assigned by the UE. In step 320, the I-CSCF 301 transmits a User Authorization Request (hereinafter, referred to as a 'UAR') message to the HSS 302. The UAR message includes a message such as a feasibility study result or a performance list of the UE. After checking the UAR message, the HSS 302 transmits a User Authorization Answer (hereinafter referred to as “UAA”) message to the I-CSCF 301 in step 330. The I-CSCF 301 Searches for the "S-CSCF management DB" and the performance DB "using the mandatory capability and optional capability of the UE delivered in the UAA message as keys.

Here, the operation referring to (Table 3) showing the S-CSCF performance DB is shown.

If the essential performance of the UE is the performance value "2,4" and the selective performance is the performance value "3", the S-CSCF list values satisfying the performance values 2 and 4 in the performance DB of Table 3 are each. Each is "6" and "4". The S-CSCF list values satisfying the performance values 2 and 4 are ANDed ("6 & 4 = 4") to obtain the S-CSCF list value 4. Also, the S-CSCF list value that satisfies the selection performance value 3 is "4".

Thus, an S-CSCF list value that satisfies the required performance and the selection performance simultaneously is obtained by performing an AND operation ("4 & 4 = 4") on the S-CSCF list values. In other words,

The S-CSCF list value that satisfies both the required performance and the selection performance becomes "4" and this value corresponds to S-CSCF 2. Accordingly, the I-CSCF obtains a host name or an IP address, which is S-CSCF information corresponding to S-CSCF 2, from the S-CSCF management DB.

In addition, when there are several S-CSCFs satisfying the essential performance and the selection performance at the same time, a method of selecting an S-CSCF is shown in Table 4 below.

As shown in Table 4, when there are four S-CSCFs that satisfy the required performance and the optional performance, the value of the Call-ID Header assigned by the UE delivered to the SIP message (for example, the header value is 10). S-CSCF 2 corresponding to 2, the remaining value divided by 4, the S-CSCF number is selected. This is to distribute the load of S-CSCFs as much as possible.

After the S-CSCF is selected as described above, the registration message is transmitted to the selected S-CSCF 303 in step 340 to proceed with the S-CSCF registration procedure.

3 is a flowchart illustrating a database configuration procedure of S-CSCF information according to a preferred embodiment of the present invention.

In step 305, the I-CSCF receives host information and performance information of the S-CSCF as an operator command. If the host name of the S-CSCF already exists in the S-CSCF management DB in step 310, the operator command fails in step 315, and if the host name does not exist, proceed to step 320 to the S-CSCF. , Assigns an unassigned index. If there is no index allocated in step 325, the operator command fails in step 315.

Check whether the S-CSCF capability information already exists in the capability DB, and if it does not exist in step 330, generate a list value of the corresponding performance value to include the allocated S-CSCF index in step 335, and in step 330 If the performance information already exists, the list value is updated to the corresponding performance value to include the allocated S-CSCF index value in step 340. In step 345, when there is a plurality of performance information of the S-CSCF, it is determined whether all the performance information is applied to the performance DB. If not all, the process returns to step 330. If all the performance information is applied to the performance DB, in step 350, the host information of the S-CSCF is written in the management DB of the S-CSCF. And outputs the configuration results of the management DBs.

4A-4B are flow diagrams illustrating a flow for selecting an S-CSCF in an I-CSCF according to a preferred embodiment of the present invention.

4A to 4B are flow charts for selecting an S-CSCF having I-CSCF that satisfies the performance of a plurality of S-CSCFs.

In step 401, a registration message is received from the UE and the HSS is requested for performance information of the UE. In step 403, the I-CSCF receives the performance information of the UE from the HSS. If the required performance of the UE does not exist in the performance information in step 405, the I-CSCF fails the operator command in step 419, and the required of the UE. If the performance exists, in step 407, S-CSCF list values of the performance DB corresponding to the performance value of the required performance are obtained. If the number of list values is one in step 409, the list value is set to a man_scscf (mandatory S-CSCF) value in step 413. If the value of the list is two or more, in operation 411, the list values are ANDed to calculate a man-scscf value. If the man-scscf value is 0 in step 415, the I-CSCF fails the operator command in step 419. If the man-scscf value is not 0, the I-CSCF checks whether there is more essential performance in step 417. If there is more performance required, return to 407. If the required performance no longer exists, the I-CSCF checks whether the selective performance exists in the performance information in step 421. If there is no selection capability, in step 423 an appropriate S-CSCF is selected from the S-CSCF capability DB using the msn-scscf value. However, if the selection capability exists, the flow proceeds to step 451 of FIG. 4B.

In step 451, an S-CSCF list value of a performance DB corresponding to the performance value of the selection capability is obtained. If the number of list values is one in step 453, the list value is set as an opt_scscf (selected S-CSCF) value in step 457. If there are two or more values in the list, in operation 455, the list values are logically calculated to calculate an opt-scscf value. If the opt-scscf value is 0 in step 459, the I-CSCF fails the operator command in step 461. If the opt-scscf value is not 0, the I-CSCF checks whether there is more selection capability in step 463. If there is more selection capability, return to 451. If there is no more selection capability, in step 465, the I-CSCF calculates a result_scscf value through an AND operation of man_scscf and opt_scscf. If the result_scscf value is 0, an appropriate S-CSCF is selected using the man_scscf value in step 471. If the result_scscf value is not 0, the control proceeds to step 469 to select an appropriate S-CSCF using the result_scscf value. .

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various modifications within the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

In the present invention that operates as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

The present invention can be effectively used in the implementation of an IMS network by selecting the S-CSCF based on the information by setting the relationship according to the S-CSCF information and serving performance for the I-CSCF to select the S-CSCF in the IMS network. There is an advantage to that.

Claims (5)

10. A method for an outgoing call session control function (I-CSCF) to select a serving call session control function (S-CSCF) in an IP-based multimedia subsystem (IMS) network. Receiving host information and performance information of the S-CSCF using an operator command; Configuring a management database (DB) including host information and performance information of the input S-CSCF; Configuring a performance DB for establishing a relationship between serving performance and the S-CSCF using the management DB; The method of selecting a serving call session control unit comprising: searching for the management DB and the performance DB using the capability information of the terminal requiring registration, and selecting the S-CSCF supporting the capability of the terminal. . The method of claim 1, wherein the performance DB, The method of claim 1, wherein index values of S-CSCF combinations supporting the corresponding capabilities for each of the plurality of capabilities are managed in the form of a bit array. The method of claim 1, wherein the selecting of the S-CSCF comprises: Determining a first S-CSCF combination supporting essential performance included in the performance information of the terminal; Selecting one S-CSCF from the first S-CSCF combination when there is no selection capability included in the capability information of the terminal; If the selectivity is present, determining a second S-CSCF combination that supports the selectivity; And selecting one S-CSCF included in both of the first S-CSCF combination and the second S-CSCF combination. The method of claim 3, wherein when the selectivity is not present, If there are two or more S-CSCFs included in the first S-CSCF combination, the call ID value transmitted from the terminal is divided by the number of S-CSCFs included in the first S-CSCF combination. A method for selecting a serving call session control unit, characterized in that selecting an S-CSCF having an index. The method according to claim 3, wherein if there are two or more S-CSCFs included in both the first S-CSCF combination and the second S-CSCF combination, the call ID value transmitted from the terminal is transferred to the first S-CSCF combination. And selecting an S-CSCF having an index corresponding to the remaining value divided by the number of S-CSCFs included.

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