KR20050103050A - Method and system for establishing a session of a called user equipment for session-based messaging with intermediate nodes in internet protocol multimedia subsystem - Google Patents

Abstract

The present invention relates to a method related to session establishment in a method for supporting session messages based on a 3GPP IMS or 3GPP2 IP Multimedia Subsystem / IP Multimedia Domain (MMD) system proposed to support a multicast service. In the method proposed in the present invention, an intermediate node is involved and proposes a session establishment method for a receiving terminal to invite a Message Session Relay Protocol (MSRP) session when the SBLP is not used. Accordingly, the present invention can use SIP for service control, and can provide a messaging service even when the calling terminal cannot maintain the session or when the receiving terminal wants to attract the session. Intermediate nodes, such as application servers, can also participate in session establishment, allowing sequentiality of services determined from user profiles stored in the HSS, enabling location update services, or ending sessions in pre-pay services. The same can be used for subsequent transactions.

Description

Method and System for Establishing A Session of A Called User Equipment For Session-Based Messaging With Intermediate Nodes In Internet Protocol Multimedia Subsystem in IP Multimedia Subsystem

IP Multimedia Core Network Subsystem (hereinafter referred to as " IMS ") of the present invention relates to a method for forming a session and a system thereof. Particularly, a session is hosted even at a destination terminal by using an intermediate node connected to the IMS. The present invention relates to a session forming method and a system of a called terminal using an intermediate node in an IMS for hosting.

In response to the rapid development of mobile communication and Internet technology and various demands of subscribers, the recent mobile communication service provides a high speed packet data service capable of transmitting a large amount of digital data as well as e-mail or still images to a mobile terminal as well as the existing voice call service. The mobile communication system is evolving from voice-based CS (packet switched) domain to packet-based packet switched (PS) domain.

Core networks (hereinafter referred to as "CNs") for providing multimedia services through the Internet are changing from conventional circuit-based CNs to packet-based CNs, and further evolving into IP-based CNs. A communication system that provides IP multimedia service (IM service) to subscribers through the IP-based CN is called IMS. In the 3GPP (Third Generation Partnership Project) / 3GPP2, various researches for smoothly providing ALL IP services through the IMS are performed. I'm going.

The IMS consists of a collection of signaling and bearers associated with the network elements and must have access to voice, video, message data and web-based technologies for wireless subscribers. In addition, since the IMS provides various types of packet data services based on an IP transport protocol, an IMS user can use a session based message to provide multimedia type content such as pictures, video clips, and sound clips. Interchangeable.

Important functional elements of the so-called IM CN subsystem for providing IM (IP Multimeida) services in the IMS include a call session control function (CSCF) that performs registration and multimedia call processing using the Session Initiation Protocol (SIP) and the existing. Home Subscriber Server (HSS) which integrates and manages mobility management and authentication of IM service users in the Home Location Register (HLR) of a mobile domain (legacy domain).

In addition, the SIP protocol is used in the IMS to provide connectivity with an existing Internet network and independence of an access network. The SIP is used as a signaling protocol for creating / modifying / terminating an IM service session, and its role is to exchange information for controlling a message session between subscribers who want to exchange messages. Since the SIP message transmitted through the SIP operates regardless of the User Datagram Protocol (UDP) and the Transmission Control Protocol (TCP), the SIP body is independent of the lower transmission protocol and uses a message body for negotiating session information using the Session Description Protocol (SDP). message body).

In the IMS, an MSRP (Message Session Relay Protocol) session, which is a protocol for transmitting a series of instant messages using the SDP, is operated for a session-based messaging service. One of the conventionally proposed methods related to the session-based messaging service includes an application server (hereinafter referred to as "AS"), a multimedia resource function controller (MRFC), or a multimedia resource function processor (MRFP) operating as an intermediate node. When a service-based local policy (SBLP) is excluded from the environment, the calling terminal forms a session-based message.

However, in the method in which the calling terminal forms a session-based message, there is a problem that a normal messaging service is not provided when the calling terminal lacks resources to host an MSRP session or when the called terminal wants to host an MSRP session.

It is an object of the present invention to provide a method and system for forming a session by hosting a session when a receiving terminal hosts a session-based messaging service in an IMS in which a service-based regional policy is excluded.

In the IP multimedia sub system for achieving the above object, the session establishment method of a called terminal using an intermediate node is a session establishment method of a mobile terminal in the IP multimedia subsystem, wherein a call session controller (CSCF) is connected to the first visitor network. Providing an access point of a called originating terminal, providing an access point of a called terminal connected to a second visitor network under the control of the call session controller, and controlling the first intermediate node and the called terminal under the control of the call session controller. Performing a TCP setup between the second intermediate node and the originating terminal under the control of the call session controller, and performing a TCP setup between the called terminal and the originating terminal through the first and second intermediate nodes. It characterized in that it comprises the process of forming an MSRP session.

The IP multimedia subsystem in which the terminating terminal establishes a session to achieve the above object is an IP multimedia subsystem that provides session-based messaging service. The IP multimedia subsystem communicates with a visitor network and uses a session initiation protocol (SIP) message to communicate with each communication node. A mobile terminal for transmitting and receiving a request / response message for the mobile terminal, a call session controller (CSCF) for providing a connection point for the mobile terminal to be connected to the IP multimedia subsystem and performing call processing for the mobile terminal, and the call And a middle node forming an MSRP session of the mobile terminal when a call request from a session controller is received.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

First, the basic concepts of the present invention and terms used in the description of the present invention will be described.

The present invention proposes a method for a destination terminal to host a session through an intermediate node of the IMS. To this end, in the present invention, a distributed server that can access CSCF or HSS transmits an invite message to an intermediate node to perform a call request, and the intermediate node that receives the invite message is a CSCF. Send a response message (eg, 100 trying messages). The invite message and the 100 trying message follow, for example, the format specified in the RFC.

In addition, the present invention is characterized in that an intermediate node (eg, AS, MRFC, MRFP) contributes to session establishment by interworking with CSCF, without using a service-based regional policy (SBLP) in establishing a session in a session-based messaging service. do.

The service-based regional policy (SBLP) is to guarantee the quality of service (QoS) of the bearer service in the IMS by determining the relationship between the SIP / SDP session level and the bearer level in the IMS. Set up a SIP session.

The intermediate nodes MRFC and MRFP are for performing bearer setup control between a mobile terminal (hereinafter referred to as "UE") and, for example, a gateway GPRS support node (GGSN) of a universal mobile telecommunications system (UMTS) network. .

The message required in the present invention is largely classified into three types. One is a SIP message, the other is a transport protocol message, and the other is an MSRP message. The session-based messaging described above uses the SIP message, which is delivered in a well known request / response manner.

1 is a network diagram showing the configuration of an IP multimedia subsystem (IMS) in which a session is formed using an intermediate node according to the present invention. In the present invention, the overall network configuration is logically based on the location of the network where the subscriber is located. It is divided into a divided CSCF, a UE communicating with the CSCF, and an AS, MRFC, and MRFP serving as the intermediate node.

In FIG. 1, it is assumed that ASs 15a and 15b are used as intermediate nodes. When the UEs 11a and 11b move from the home network to the external network, the UEs 11a and 11b, the intermediate nodes 15a, 15b, and 15c in the overall network configuration, respectively, In this configuration, the CSCFs 12a, 12b, 13a, 13b, and 14 are connected, and under these circumstances, the S-CSCFs 13a and 13b each receive the intermediate nodes 15a and 15b, so that MSRP sessions between the US 11a and 11b are performed. To form.

In this regard, the operation of the CSCFs is described as follows.

The CSCF is classified into Proxy-CSCF (hereinafter referred to as "P-CSCF"), Serving CSCF (hereinafter referred to as "S-CSCF"), and Interrogating CSCF (hereinafter referred to as "I-CSCF") according to its location and role. The functions of the CSCFs are as follows. Firstly, the P-CSCF is the first point at which the UE connects to the IM service network and exists in the same domain as the GGSN. The P-CSCF requests / responses a SIP message with the UE, delivers a SIP message delivered from the UE to the S-CSCF, and delivers a SIP message delivered from the S-CSCF to the UE.

The S-CSCF manages a session state of a UE, stores subscriber information of a UE delivered from an unshown HSS, performs subscriber authentication in association with an HSS, and sends a SIP message delivered from a P-CSCF to an I-CSCF. To pass. In the present invention, the S-CSCFs 13a and 13b perform an invite, that is, a call request for the ASs 15a and 15b which are intermediate nodes. The I-CSCF is the first point to connect to different home networks (operator networks), and the I-CSCF routes SIP messages received from other home networks to the S-CSCF.

Accordingly, the P-CSCF 12a of FIG. 1 is the Proxy-CSCF, and the UE 11a is first contacted when receiving the IMS service, and the S-CSCF 13a is located in the home network as the Serving-CSCF and thus the UE 11a. Handles the SIP session. Meanwhile, the I-CSCF 14 is an Interrogating-CSCF, which is located at the point of contact between other operator networks. In this configuration, the S-CSCF 13a serves the AS 15a, and the AS 15a records the record route for later transactions, for example for a pre-pay service. You will add your location to the.

Meanwhile, processes 101 to 133 illustrated by arrows in FIG. 1 sequentially show a process of performing a SIP session and an MSRP session according to the present invention. The invite process for the AS 15a is represented in steps 101 to 119, and a detailed description thereof will be described later. In addition, a specific service may be used to redirect the session in connection with updating a location. An example of this may be seen in the AS 15c. The part-time process of steps 131 to 133 represents this. In this case, the AS 15c does not participate in subsequent transactions. In addition, processes 121 through 125 in which a message path is set from the UE 11a to the UE 11b via the ASs 15a and 15b, which are intermediate nodes, indicate MSRP session establishment. In this case, the MSRP session for transmitting the actual message is established between the UEs 11a and 11b and the ASs 15a and 15b. The MSRP session is formed through the above-described SDP negotiation.

Hereinafter, a method of establishing a session of a called terminal using an intermediate node in an IP multimedia subsystem according to an embodiment of the present invention will be described with reference to FIGS. 2A to 2D.

2A to 2D illustrate a process in which a called terminal invites an MSRP session through an intermediate node while excluding a precondition or service based regional policy (SBLP) proposed by the present invention.

First, in step 201 and 202, UE # 1 transmits a SIP INVITE message to P-CSCF # 1, and P-CSCF # 1 transmits a response message 100 Trying to UE 11a. The SDP sent along with this SIP INVITE message sets the directionality of the MSRP to active. This is to attract MSRP session in UE # 2. In steps 203 to 204, the P-CSCF # 1 and the S-CSCF # 1 transmit and receive an INVITE message and a response message thereto, which is the same as the proxying method.

In steps 205 to 207, the S-CSCF # 1 transmits a SIP INVITE message to another CSCF or an intermediate node according to an initial filtering criterion. In this embodiment, transmission to AS # 1 is assumed. In this case, S-CSCF # 1 sends the INVITE message to AS # 1, and AS # 1 responds to it with S-CSCF # 1, which is the same as SIP Proxying.

In steps 208 to 211, AS # 1 generates a new SIP INVITE message and sends it to S-CSCF # 1, S-CSCF # 1 sends a response message to AS # 1, and S-CSCF # 1 and S-CSCF. # 2 sends and receives messages in the same way. In step 212, I-CSCF # 2 sends an inquiry to HSS not shown to find S-CSCF # 2. In steps 213 and 214, S-CSCF # 1 and S-CSCF # 2 respond to a SIP INVITE message and its response message. Send and receive

In step 215, S-CSCF # 2 transmits a SIP INVITE message to another CSCF or an intermediate node according to the initial filtering criteria. In this embodiment, transmission to AS # 2 is assumed. In this case, S-CSCF # 2 sends the INVITE message to AS # 2, and AS # 2 responds to it with S-CSCF # 2, which is the same as SIP Proxying.

In step 218 to 223, the AS # 2 generates a new SIP INVITE message and transmits it to S-CSCF # 2, which is sent to P-CSCF # 2 and UE # 2, and the response message for each is SIP Proxying. Is the same as In step 224, UE # 2 allocates an IP-CAN Bearer (IP-Connectivity Access Network bearer). The IP-CAN means a network providing IMS services to IMS subscribers.

  In step 225 to 227, the 200 OK message is transmitted and received between the corresponding UE. The included SDP answer sets the directionality of the MSRP to Passive, and sets the TCP port number and the URL for the MSRP session. This process enables TCP setup between UE # 2 and AS # 2. Accordingly, the UE # 2 and the AS # 2 perform a TCP set up process in step 228.

Thereafter, 200 OK messages are transmitted between the corresponding UEs in steps 229 to 232. In the included SDP answer, the directionality of the MSRP is set to Passive, and the TCP port number and the URL for the MSRP session are set. This process enables TCP setup between AS # 2 and AS # 1. In step 233, AS # 2 and AS # 1 perform a TCP set up process.

In step 234 to 236, 200 OK messages are transmitted between the corresponding UEs. In this case, the SDP response includes a directionality of the MSRP as Passive, and a TCP port number and a URL for the MSRP session are set. This process enables TCP setup between AS # 1 and UE # 1. In step 237, UE # 1 allocates the aforementioned IP-CAN Bearer using the received session URL, and in step 238, TCP setup between AS # 1 and UE # 1 is performed.

Thereafter, the VISIT and the 200 OK message for the MSRP session are transmitted between the UEs in steps 239 to 244, and the ACK message for the SIP message is transmitted between the UEs in steps 245 to 253. In steps 254 to 259, SEND messages and 200 OK messages related to actual data transmission of the MSRP are transmitted between corresponding UEs.

Hereinafter, a method of establishing a session of a called terminal using an intermediate node in an IP multimedia subsystem according to an embodiment of the present invention will be described with reference to FIGS. 3A to 3D.

3A-3D are flow diagrams illustrating an embodiment of another case where a terminating UE establishes an MSRP session for a proposal of a SIP session of an originating UE. In the present embodiment, it is assumed that intermediate nodes exist while excluding SBLP, and the originating UE transmits by setting the directionality as both directions, and the destination UE sets the directionality to passive to establish the MSRP session. It shows the case of hosting.

In step 301, UE # 1 allocates an IP CAN bearer for receiving an IMS service. In step 302, the UE # 1 sends a SIP INVITE message to the P-CSCF # 1. In the SDP transmitted along with the SIP INVITE message, the direction of the MSRP is set to both directions. In operation 303 to 305, an INVITE message and a response message are transmitted between the UE # 1, the P-CSCF # 1, and the S-CSCF # 1.

Thereafter, in step 306, S-CSCF # 1 transmits a SIP INVITE message to another CSCF or an AS server according to an initial filtering criterion. In this case, it is assumed that the data is transmitted to AS # 1. In step 307 and 308, S-CSCF # 1 transmits an INVITE message to AS # 1, and S-CSCF # 1 receives the response message from AS # 1. In step 309, a TCP setup process is performed between UE # 1 and AS # 1.

In step 310 to 313, AS # 1 generates a new SIP INVITE message and transmits it to S-CSCF # 1, and S-CSCF # 1 sends a response message to AS # 1, and S-CSCF # 1 and The SIP INVITE message and its response message are transmitted and received in the same manner between I-CSCF # 2.

In step 314, I-CSCF # 2 sends an inquiry message to an HSS not shown to find S-CSCF # 2. In steps 315 and 316, I-CSCF # 2 and S-CSCF # 2 respond to a SIP INVITE message and its response. Send and receive messages. In step 317, S-CSCF # 2 transmits a SIP INVITE message to another CSCF or an intermediate node according to the initial filtering criteria. In this embodiment, it is assumed that the transmission to AS # 2. In this case, in step 318 and 319, S-CSCF # 2 transmits an INVITE message to AS # 2, and AS # 2 responds to it by sending a message to S-CSCF # 2, which is the same as SIP proxying.

Thereafter, in step 320, AS # 2 and AS # 1 perform a TCP set up process. In operation 321 to 326, the SIP INVITE message and the response message are transmitted and received between the corresponding UEs. Thus, AS # 2 generates a new SIP INVITE message and sends it to S-CSCF # 2, which is in turn sent to UE # 2 via P-CSCF # 2. The trying response is the same as SIP Proxying.

UE # 2 allocates an IP-CAN Bearer for using the IMS service in step 327, and UE # 2, P-CSCF # 2 and S-CSCF # 2 sequentially transmit an OK message in steps 328 to 330. In this case, in the SDP answer included in the 200 OK message, the directionality of the MSRP is set to Passive, and the TCP port number and the URL for the MSRP session are set. Thereafter, in step 33Ob, the AS # 2 closes the existing open TCP port and then performs a TCP setup process with the UE # 2 and the new port in step 331.

In steps 332 to 335, the AS # 2, the S-CSCF # 2, the I-CSCF # 2, and the S-CSCF # 1 sequentially transmit 200 OK messages. In this case, in the SDP answer included in the 200 OK message, the directionality of the MSRP is set to Passive, and the TCP port number and the URL for the MSRP session are set. Subsequently, AS # 1 closes the existing open TCP port in step 335-b, and performs TCP setup with AS # 2 and the new port in step 336.

Thereafter, in steps 337 to 339, the AS # 1, S-CSCF # 1, and P-CSCF # 1 sequentially transmit 200 OK messages, and in this case, set the directionality of the MSRP to Passive in the SDP response included, and TCP The port number and URL for the MSRP session are set. In step 340, the UE # 1 closes the existing open TCP port, and in step 341, the UE # 1 performs a TCP set up process with the new port.

In operation 342 to 347, the VISIT message and the 200 OK message are transmitted between the corresponding UEs. In operation 348 to 356, an ACK message for the SIP message is transmitted and received between the UEs. In operation 357 to 362, SEND and 200 OK messages related to actual data transmission of the MSRP are transmitted between the corresponding UEs.

As described above, according to the present invention, when there is an intermediate node without using a precondition or a service-based regional policy, the called terminal may form an MSRP session in the IP multimedia subsystem.

In addition, according to the present invention, when providing a session-based messaging service provides a method for hosting a session in the destination terminal, not the originating terminal, so that the destination terminal hosts the session when the resources of the originating terminal is insufficient to host the session. You can do it.

In addition, according to the present invention, intermediate nodes, such as application servers, may be involved in session establishment to allow sequentiality of the service determined in the user profile stored in the HSS, enable the service to update the location, and prepay service (pre pay). service can be used for transactions such as session termination.

1 is a network diagram showing a configuration of an IP multimedia subsystem in which a session is formed using an intermediate node according to the present invention.

2A to 2D are flowcharts illustrating a method for establishing a session of a called terminal using an intermediate node in an IP multimedia subsystem according to an embodiment of the present invention.

3A to 3D are flowcharts illustrating a session establishment method of a terminating terminal using an intermediate node in an IP multimedia subsystem according to another embodiment of the present invention.

Claims (2)

In the session establishment method of the mobile terminal in the IP multimedia subsystem, Providing, by the call session controller (CSCF), an access point of an originating terminal connected to the first visitor network; Providing an access point of a called terminal connected to a second visitor network under the control of the call session controller; Performing a TCP setup between a first intermediate node and the called terminal under the control of the call session controller; Performing a TCP setup between a second intermediate node and the originating terminal under the control of the call session controller; And forming an MSRP session between the called terminal and the calling terminal through the first and second intermediate nodes. In the IP multimedia subsystem that provides session-based messaging services, A mobile terminal communicated to the visitor network and sending and receiving request / response messages for each communication node using a Session Initiation Protocol (SIP) message; A call session controller (CSCF) which provides an access point for the mobile terminal to be connected to the IP multimedia subsystem and performs call processing for the mobile terminal; And an intermediate node that forms an MSRP session of the mobile terminal when there is a call request from the call session controller.