KR20050116464A - Method for terminating session based messaging service in internet protocol multimedia sub-system - Google Patents

Abstract

The present invention discloses a method for releasing an MSRP session and a SIP session in a session based messaging service of an internet multimedia subsystem. A method of terminating a session-based messaging service performed through a message session relay protocol (MSRP) session formed through a session initiation protocol (SIP) session in an internet multimedia subsystem, includes two terminals performing the session-based messaging service. Sending a termination request message to one terminal to terminate the session-based messaging service by the other terminal, releasing the MSRP session related to the session-based messaging service, and the other terminal in response to the termination request message; Releasing the MSRP session related to the session-based messaging service, and transmitting a response message to the one terminal. When the session-based messaging service is formed via at least one intermediate node, the at least one intermediate node recognizes an end request message transmitted from the one terminal in the direction of the other terminal, and then the direction of the one terminal. Release the MSRP session associated with the session based messaging service prior to sending the response message.

Description

Termination method of session-based messaging service of Internet multimedia subsystem {METHOD FOR TERMINATING SESSION BASED MESSAGING SERVICE IN INTERNET PROTOCOL MULTIMEDIA SUB-SYSTEM}

The present invention relates to an internet multimedia subsystem, and more particularly to a method for releasing sessions for a session based messaging service of a multimedia subsystem based on the Internet Protocol.

3GPP (3rd Generation Partnership Project) Internet Protocol (IP) Multimedia Subsystem (IMS) or 3GPP2 Multimedia Domain (MMD) is introduced to provide IP-based packet communication services in 3G mobile communication networks. It became. As the Internet access through the mobile communication network is enabled as described above, researches for accessing various services available only on the Internet to the mobile communication system have been made.

On the other hand, with the spread of the Internet and the increased use of computers in everyday life, most Internet users use simpler and faster messaging than regular e-mails to communicate with their colleagues or buddy. I prefer to use the service. IP Multimedia Sub-system (IMS) provides a messaging service that allows users to exchange IP-based user messages with each other. Messaging services provided by the IP multimedia subsystem include instant messaging and session-based messaging services.

Instant messaging is a method of delivering a short user message or a short media message to a SIP message exchanged through a Session Initialization Protocol (SIP) session, which is typically used for initiating initial Internet communication. . Unlike instant messaging, user messages in session-based messaging are carried in MSRP messages over Message Session Relay Protocol (MSRP) sessions formed through SIP sessions. MSRP messages used in session-based messaging are relatively simpler than SIP messages, exchanged over SIP sessions, and delivered through SIP messages because they receive Congestion Control (Transfer Control Protocol). Larger message exchanges are possible compared to instant messaging.

Session-based messaging services are implemented with signaling in Session Initiation Protocol (SIP) sessions and data transmission over Message Session Relay Protocol (MSRP) sessions. 3GPP TS 23,228 defines that SIP sessions and MSRP sessions are formed with independent directions. In the case of a SIP session, the originating terminal initially establishes an SIP session and is formed by the receiving terminal answering it. In the case of an MSRP session, a terminal to determine a session is determined when the session is established. Accordingly, the session is formed when the originating terminal first proposes a SIP session and simultaneously invites an MSRP session (originating UE hosting). And, it may be classified as a case where the originating terminal proposes a SIP session and the receiving terminal invites an MSRP session.

After the exchange of messages between the originating terminal and the receiving terminal, the MSRP session is closed by closing the SIP session, thereby terminating the messaging service. In this case, resources related to TCP and other resources used by both terminals are returned. The conventional IP multimedia subsystem has a problem in that it does not provide a detailed operation of releasing MSRP and SIP sessions at both terminals. Therefore, there is a need for a method for releasing MSRP and SIP sessions using SIP and MSRP.

It is therefore an object of the present invention, devised to solve the problems of the prior art operating as described above, to provide a method for terminating a session based messaging service in an internet multimedia subsystem.

Another object of the present invention is to provide a method for both terminals performing a session-based messaging service in an internet multimedia subsystem to release an MSRP and SIP session.

An embodiment of the present invention, which was created to achieve the above object, is a session-based messaging service performed through a message session relay protocol (MSRP) session that is formed through a session initiation protocol (SIP) session in an Internet multimedia subsystem. In the end method of,

One of two terminals performing the session-based messaging service without intermediate nodes transmits an end request message for terminating the session-based messaging service to the other terminal and sends the MSRP session related to the session-based messaging service. To turn it off,

The other terminal releases the MSRP session related to the session-based messaging service in response to the termination request message, characterized in that it comprises the step of transmitting a response message to the one terminal.

Another embodiment of the present invention provides a method for terminating a session-based messaging service performed through a message session relay protocol (MSRP) session formed through a session initiation protocol (SIP) session in an internet multimedia subsystem.

One of the two terminals performing the session-based messaging service through at least one intermediate node transmits a termination request message for terminating the session-based messaging service to the other terminal through the at least one intermediate node, Releasing the MSRP session associated with the session based messaging service;

Releasing, by the other terminal, the MSRP session related to the session-based messaging service in response to the termination request message, and transmitting a response message to the one terminal through the at least one intermediate node;

And the at least one intermediate node releasing the MSRP session associated with the session based messaging service in response to the response message.

Another embodiment of the present invention provides a method of terminating a session-based messaging service performed through a message session relay protocol (MSRP) session formed through a session initiation protocol (SIP) session in an internet multimedia subsystem.

One of two terminals performing the session-based messaging service through at least one intermediate node sends a termination request message to the at least one intermediate node to terminate the session-based messaging service, and the session-based messaging. Releasing the MSRP session related to the service;

After the at least one intermediate node forwards the termination request message to a subsequent intermediate node or the other terminal, the MSRP session related to the session-based messaging service is released in response to the termination request message, and the intermediate node of the previous stage is released. Or transmitting a response message to the one terminal.

In response to the termination request message, the other terminal releases the MSRP session related to the session-based messaging service and transmits a response message to the at least one intermediate node.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the preferred embodiment of the present invention. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. 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 invention described below relates to a messaging service in an IP multimedia subsystem. As mentioned earlier, the IP multimedia subsystem supports instant messaging and session-based messaging services to enable users to exchange IP-based user services.

Figure 1 illustrates two messaging services provided by the IP multimedia subsystem, instant messaging and session-based messaging services.

Referring to FIG. 1A, user messages 101 in instant messaging are carried in SIP messages. The IP core network has a Call State Control Function (CSCF) 103 that manages procedures related to every call or session. All SIP messages are exchanged through the CSCF 103. Because instant messaging uses SIP messages directly, it does not form a separate MSRP session for sending MSRP messages, and therefore does not form a SIP session for establishing an MSRP session. Messages delivered between both terminals are regarded as independent messages irrelevant to each other and processed by the CSCF 103 regardless of their temporal order.

Referring to FIG. 1B, a session based messaging service is used for the exchange of consecutive user messages having the same characteristics. In this case, each user message is transmitted through MSRP message through TCP, not SIP message. Therefore, a SIP session is needed to create an MSRP session. Here, the SIP message is shown by the dotted line and the MSRP message is shown by the solid line.

For session-based messaging services, a SIP message 105 is first sent via CSCF 107 to create a session between both terminals. When a SIP session is created, an MSRP session is created through the SIP session. MSRP messages 109 containing the user message are then delivered over the TCP connection used in the MSRP session established via the SIP session. When the exchange of MSRP messages between both terminals is completed, the SIP message 111 for closing the SIP session is delivered, thereby ending the MSRP session and ending the messaging service.

Figure 2 illustrates the operation of sending a SIP message in the 3GPP IP multimedia subsystem.

Referring to FIG. 2, the terminals 10, 20 communicate with each other via IP multimedia subsystem networks 12, 16, 22, 26. The terminals 10 and 20 in their home networks 12 and 22 or in the visited networks 14 and 24 may exchange text or multimedia messages with each other using a messaging service. Home networks 12, 22 use Serving CSCF (S-CSCF) 14, 24 to carry SIP messages and manage sessions, while visiting networks 16, 28 are proxy CSCF ( Proxy CSCF: P-CSCF) (18, 30). The home networks 12, 22 communicate with each other by an Interrogating CSCF (I-CSCF) 26.

The P-CSCFs 18 and 30 are functional nodes that are first contacted by terminals when they are serviced by the IP multimedia subsystem and exist in the terminal's home network or external network. The S-CSCFs 14 and 24 actually exist in the home network of the terminal as a functional node that processes and manages the SIP session state of the terminal. I-CSCF 26 is used as a point of contact between different operator networks and is the first CSCF to pass when a SIP session is established between different operator networks.

All kinds of SIP request / response messages have Via headers as extension headers indicating the route of the message. For example, although only the address of UE # 1 exists in the Via header of the SIP message originating from UE # 1, the P-CSCF # in the Via header passes through P-CSCF # 1 and S-CSCF # 1. 1, the address of S-CSCF # 1 is added continuously. At each node, the SIP message is delivered to the highest address of the Via header.

In FIG. 2, the calling terminal UE # 1 and 10 and the receiving terminal UE # 2 and 20 located in the visited networks 16 and 28 respectively exchange SIP messages through the home networks 12 and 22. The operation to be described in detail.

In step 201, a SIP session is established between the CS # 1 10 and the UE # 2 20 via CSCFs 18, 14, 26, 24, and 30. In addition, in step 203, an MSRP session separate from the SIP session is formed to transmit messages, wherein media characteristics of the MSRP message to be delivered through the MSRP session are negotiated through the SIP session. SIP sessions are established through CSCFs 18, 14, 26, 24, and 30, whereas MSRP sessions are established by normal TCP connections.

The SIP message delivered by UE # 1 10 to establish a SIP session is delivered to P-CSCF # 1 18, which is the initial point of contact of the external network 16 on which UE # 1 10 is currently located. The P-CSCF # 1 18 finds the home network 23 of the UE # 1 10 and delivers the SIP message to the corresponding S-CSCF # 1 14 of the UE # 1 10. S-CSCF # 1 14 finds the home network 22 of UE # 2 20 to which UE # 1 10 wishes to establish a SIP session, and forwards the SIP message to the home network 22. do.

The SIP message delivered by the S-CSCF # 1 14 is first delivered to the I-CSCF # 2 26 of the home network 22. The I-CSCF # 2 26 delivers the SIP message to the S-CSCF # 2 24 corresponding to the UE # 2 20. S-CSCF # 2 24 finds the external network 28 where the UE # 2 20 that it provides services is now located and forwards the SIP message to the external network 28. Finally, a SIP message is transmitted to UE # 2 20 from P-CSCF # 2 30 of the external network 28.

SIP messages from UE # 2 20 to UE # 1 10 are delivered in the reverse order. By exchanging the above SIP messages, a SIP session is established between UE # 1 and UE # 2.

Figure 3 illustrates in more detail the relationship between a SIP session and an MSRP session in session-based messaging.

Referring to FIG. 3, the main role of SIP is to suspect, form, and finally terminate a media session defined in Session Description Protocol (SDP). In the SIP session negotiation process 301 for session-based messaging, SDP arguments are exchanged between two terminals to determine media and characteristics of a session to be used in a SIP session. The formed SIP session then maintains the determined media and session characteristics. Media and session characteristics may change through a session conversion process.

Simultaneously with the establishment of the SIP session, MSRP parameters are exchanged for use in exchanging MSRP messages in step 303. The arguments used here include the identifier of the SIP session, the addresses of both terminals, and the TCP port number used to exchange MSRP messages. If necessary, the host that reserves the TCP connection may reserve resources including the TCP port.

In step 305, an MSRP session corresponding to a SIP session is formed using the MSRP factors. In this case, a plurality of MSRP sessions may be formed for a single SIP session. The MSRP session between both terminals is established using the already exchanged address and TCP port number.

In step 307, an MSRP message is transmitted through the MSRP session. After the exchange of messages between the two terminals in step 309, the MSRP session is closed by closing the SIP session to terminate the messaging service. At this time, TCP and other resources used by both terminals are returned.

The present invention proposes a release operation and sequence of a SIP session and an MSRP session when providing a session-based messaging service in an IP multimedia subsystem. The following describes a session release operation in the session-based messaging service in two cases. The first case is a case in which a source terminal and a receiving terminal roam to a network other than the home network (that is, a visited network) to receive a service and use a single TCP connection without passing through an intermediate node. In the second case, an application server (AS), which acts as an intermediate node, participates in a session formation process between the calling terminal and the receiving terminal, and a TCP session for transmitting a message is formed through the intermediate node. The intermediate nodes participate in the establishment of an MSRP session, and serve as intermediate paths through which SIP and MSRP messages are delivered.

According to a preferred embodiment of the present invention, the SIP session and the MSRP session are released by the SIP BYE request message defined in RFC-3261.

When the UE, the intermediate node, and the CSCFs of the IP multimedia subsystem receive the SIP BYE request message, they send the SIP BYE request message to the CSCF, AS or UE, which is a SIP UA (User Agent) located at the top of the Via header indicating a delivery path. Then, the SIP session is terminated by removing the SIP session and the states related to the SIP transaction and the SIP dialog. When the AS or the UE receives the SIP BYE request message, the AS or the UE terminates the MSRP session by removing states related to the corresponding MSRP session and the TCP connection.

A detailed operation example of a session release method according to a preferred embodiment of the present invention will be described below. Detailed operations performed in each of the terminals and the intermediate node AS will be described with reference to FIGS. 7, 8, and 9.

4 is a flowchart illustrating a message flow when a single TCP connection is used without passing through an intermediate node in a situation where a calling terminal and a receiving terminal are serviced in a visited network according to a preferred embodiment of the present invention. This shows the arrival when one terminal UE # 1 receiving the IP multimedia subsystem service from the P-CSCF # 1 of the visited network requests the other terminal UE # 2 to terminate the MSRP service. The UE # 2 also leaves its home network and receives a service from the P-CSCF # 2 of the visited network.

Each home network, external network, P-CSCF, I-CSCF, and S-CSFC have been described with reference to FIG. 2. In the following description, an IP-Capable Access Network (IP-CAN) bearer is a transmission path of a radio access network used for transmitting a SIP message or an MSRP message. In the following, it is assumed that an IP-CAN bearer for transmitting a SIP message is already allocated, and only considers an assignment of an IP-CAN bearer used for transmitting an MSRP message of an MSRP session. Each IP-CAN bearer is assigned one per MSRP session.

In step 401, UE # 1 transmits an MSRP SEND message including user data to UE # 2. That is, UEs establish an MSRP session for a session-based messaging service, and then directly transmit the MSRP SEND message to the other party using a wire URL (Uniform Resource Locator) and TCP port number. User data to be transmitted is included in the MSRP SEND message. In step 403, UE # 2 transmits an MSRP 200 OK message in response to the MSRP SEND message received from UE # 1.

In step 405, UE # 1 sends a SIP BYE request message to terminate the session-based messaging service. After transmitting the SIP BYE request message, in step 407, UE # 1 removes the SIP session and MSRP session related states and the TCP related states.

In processes 409 to 415, the SIP BYE request message is delivered to UE # 2 via P-CSCF # 1, S-CSCF # 1, S-CSCF # 2, and P-CSCF # 2. Here, the CSCFs deliver the SIP BYE request message to the CSCF or UE # 2 located at the top of the Via header. In step 417, UE # 2 releases the SIP session and the MSRP session after receiving the SIP BYE request message from UE # 1. To do this, remove the MSRP session related states and TCP related states. If all the MSRP session related states are removed, UE # 2 sends a SIP 200 OK response message in step 419.

After the MSRP session is terminated, UE # 2 releases the IP-CAN bearer in step 421. If UE # 2 later wants to use the services of the IP multimedia subsystem, it may maintain an IP-CAN bearer. Otherwise, UE # 2 releases its IP-CAN bearer and disconnects from the network.

The SIP 200 OK response message transmitted by UE # 2 in processes 423 to 429 is delivered to UE # 1 along the reverse path of the processes 405 to 415. The SIP 200 OK response message informs UE # 1 that the MSRP session and the SIP session between UE # 1 and UE # 2 were successfully released.

Since the MSRP session is completely terminated in step 431, UE # 1 releases the IP-CAN bearer. If UE # 1 later wants to use the services of the IP multimedia subsystem, it may maintain an IP-CAN bearer. Otherwise, UE # 1 releases its IP-CAN bearer and disconnects from the network.

When the intermediate node participates in the session establishment, there are two ways to release the session between the originating terminal and the receiving terminal. One is to release the entire session at once, and the other is to release the TCP connection that makes up the session. The former method is shown in FIG. 5 and the latter method is shown in FIG. How the intermediate node releases the session is determined by the policy of the network operator managing the intermediate node.

FIG. 5 illustrates a first embodiment of releasing a session when intermediate nodes participate in MSRP session establishment between the originating terminal and the receiving terminal. When the intermediate nodes participate in the MSRP session establishment, the TCP connection between both terminals is divided into multiple TCP connections. In FIG. 5, UE # 1, which is one terminal and UE # 2, which is an opponent terminal, establishes a session through two intermediate nodes AS # 1 and AS # 2, and a TCP connection between UE # 1 and UE # 2 includes: 1) a first TCP connection between UE # 1 and AS # 1, 2) a second TCP connection between AS # 1 and AS # 2, and 3) a third TCP connection between AS # 2 and UE # 2. Divided. Therefore, the actual message transmitted from UE # 1 and UE # 2 is delivered to the other party through the intermediate nodes AS # 1 and AS # 2. The session release shown in FIG. 5 is a case in which the three TCP connections are released from the TCP connection of the UE # 2 side.

In step 501, UE # 1 sends an MSRP SEND message including user data. In other words, after the MSRP session is established for the session-based messaging service, UEs directly transmit the MSRP SEND message to the other party using the other party's session URL and TCP port number. User data to be transmitted is included in the MSRP SEND message. In processes 503 to 505, the MSRP SEND message is generated by a first TCP connection between UE # 1 and intermediate node AS # 1, a second TCP connection between AS # 1 and AS # 2 and between AS # 2 and UE # 2. Is sent over the third TCP connection. The intermediate nodes forward the MSRP SEND message to the next intermediate node or UE # 2.

In step 507, UE # 2 transmits an MSRP 200 OK message in response to the MSRP SEND message. In processes 509 to 511 the MSRP 200 OK message is delivered to UE # 1 over three TCP connections.

In step 513, UE # 1 generates a SIP BYE request message to terminate the session-based messaging service. After transmitting the SIP 200 OK response message, in step 515, UE # 1 removes the states related to the SIP session and the MSRP session and the TCP related states.

In steps 517 to 519, the SIP BYE request message is delivered to the intermediate node AS # 1 via P-CSCF # 1 and S-CSCF # 1, and in steps 520 to 523, AS # 1 is the SIP BYE request message. Is transmitted to AS # 2 again via S-CSCF # 2, and in steps 524 to 527, the SIP BYE request message is delivered to UE # 2 via P-CSCF # 2.

In step 529, UE # 2 releases the SIP session and the MSRP session in response to the SIP BYE request message. To do this, remove the MSRP session related states and TCP related states. When all MSRP session related states are removed, UE # 2 transmits a SIP 200 OK response message in step 531. After the end of the MSRP session, in step 533 UE # 2 releases the IP-CAN bearer. If UE # 2 later wants to use the services of the IP multimedia subsystem, it may maintain an IP-CAN bearer. Otherwise, UE # 2 releases its IP-CAN bearer and disconnects from the network.

In processes 535 to 536, the intermediate node AS # 2 releases the MSRP session according to the SIP 200 OK response message, and then transfers the SIP 200 OK response message to AS # 1 in step 539. In steps 541 to 542, the intermediate node AS # 1 releases the MSRP session according to the SIP 200 OK response message, and then sends a SIP 200 OK response message in step 545. In processes 547 to 549 the SIP 200 OK response message is delivered to UE # 1.

In step 551, UE # 1 determines that the MSRP session is completely terminated and releases the IP-CAN bearer. If UE # 1 later wants to use the services of the IP multimedia subsystem, it may maintain an IP-CAN bearer. Otherwise, UE # 1 releases its IP-CAN bearer and disconnects from the network.

6 illustrates a second embodiment of releasing a session when intermediate nodes participate in MSRP session establishment between the originating terminal and the called terminal. Here, the TCP connection composing the entire MSRP session is released sequentially from the UE # 1 side.

In step 601, UE # 1 sends an MSRP SEND message including user data. In other words, after the MSRP session is established for the session-based messaging service, UEs directly transmit the MSRP SEND message to the other party using the other party's session URL and TCP port number. User data to be transmitted is included in the MSRP SEND message. In processes 603 to 605, the MSRP SEND message is generated by a first TCP connection between UE # 1 and intermediate node AS # 1, a second TCP connection between AS # 1 and AS # 2 and between AS # 2 and UE # 2. Is sent over the third TCP connection. The intermediate nodes forward the MSRP SEND message to the next intermediate node or UE # 2. In step 607, UE # 2 transmits an MSRP 200 OK message in response to the MSRP SEND message. In steps 609 to 611 the MSRP 200 OK message is delivered to UE # 1 over three TCP connections.

In step 613, UE # 1 transmits a SIP BYE request message to terminate the session-based messaging service. After transmitting the SIP BYE request message, in step 615, UE # 1 removes the states related to the SIP session and the MSRP session and the TCP related states.

In processes 617 to 619, the SIP BYE request message is delivered to the intermediate node AS # 1 via P-CSCF # 1 and S-CSCF # 1. In steps 620 through 621, AS # 1 sends a SIP BYE request message in response to the SIP BYE request message, and then removes the MSRP session related states and TCP related states in step 623. When all states related to the session are removed, the AS # 1 sends a SIP 200 OK response message to the UE # 1 in step 625 to notify that the TCP connection between the UE # 1 and the AS # 1 has been released.

In steps 627 to 629, the SIP 200 OK response message is delivered to UE # 1 via S-CSCF # 1 and P-CSCF # 1. In step 631, UE # 1 releases the IP-CAN bearer in response to the SIP 200 OK response message. If UE # 1 later wants to use the services of the IP multimedia subsystem, it may maintain an IP-CAN bearer. Otherwise, UE # 1 releases its IP-CAN bearer and disconnects from the network.

In step 633, the SIP BYE request message arrives at AS # 2. AS # 2 delivers the SIP BYE request message to P-CSCF # 2 in processes 635 to 635 and removes MSRP session related states and TCP related states in step 637. Once all states associated with the session are removed, in steps 639 through 642, AS # 2 sends a SIP 200 OK response message to AS # 1, indicating that the TCP connection between AS # 1 and AS # 2 has been released.

In step 643, the SIP BYE request message from P-CSCF # 2 arrives at UE # 2. In step 645, UE # 2 removes SIP session and MSRP session related states and TCP related states in response to the SIP BYE request message. When all states related to the session are removed, UE # 2 sends a SIP 200 OK response message to AS # 2 in step 647 to inform that the TCP connection between AS # 2 and UE # 2 has been released. After transmitting the SIP 200 OK response message, UE # 2 releases its IP-CAN bearer in step 649. If UE # 2 later wants to use the services of the IP multimedia subsystem, it may maintain an IP-CAN bearer. Otherwise, UE # 2 releases its IP-CAN bearer and disconnects from the network.

In steps 651 to 652, the SIP 200 OK response message is delivered to the intermediate node AS # 2, and AS # 2 recognizes that the TCP connection between AS # 2 and UE # 2 has been released according to the SIP 200 OK response message. .

7 to 9 are flowcharts illustrating operations of terminals and intermediate nodes in the embodiments illustrated in FIGS. 5 and 6.

7 is a flowchart illustrating an operation when a terminal releases an MSRP session and terminates a session based messaging service of an IP multimedia subsystem according to a preferred embodiment of the present invention. Here, the operations performed by UE # 1 in the embodiments of FIG. 5 and FIG. 6 are illustrated.

In step 701, the UE decides to start the MSRP session release for the session-based messaging service, and in step 703, the UE sends a SIP BYE request message to inform the other terminal of the release of the MSRP session and terminates the messaging service.

In step 705, the terminal removes the states associated with the SIP session and the MSRP session. The states removed at this time are as follows.

SIP Session: Call Identifier (Call-ID), Call Sequence Number

-SIP dialog related: Dialog ID, Local / remote sequence number, Local / remote URI, Remote target

SIP transaction related: timers

MSRP session related: Session URL, Transaction Identifier (TR-ID), Continuity flag

TCP connection: TCP port number, TCP window size, TCP sequence number

{{CSeq, full name of TR-ID is required}}

In step 707, the terminal waits until it receives a SIP 200 OK response message.

If the SIP 200 OK response message is received in step 709, the terminal releases the IP-CAN bearer. When the IP-CAN bearer is released, the connection with the P-CSCF is broken and the connection with the IP multimedia subsystem is terminated. Accordingly, the session release process of the UE is terminated in step 711.

8 is a flowchart illustrating a session release operation performed at an intermediate node AS when a session is released by the terminal according to an exemplary embodiment of the present invention. Here, the operations performed by AS # 1 and AS # 2 in FIGS. 5 and 6 are shown.

In step 801, the AS waits to receive a SIP message. When the SIP BYE request message arrives in step 805, the AS in step 809 changes the Via header value of the SIP BYE request message as defined in RFC 3261, and requests the SIP BYE to the destination header address of the SIP BYE request message. Pass the message. The SIP BYE message is automatically forwarded to the SIP UA located next on the path of the SIP BYE request message.

After transmitting the SIP BYE request message, in step 811, the AS proceeds to step 813 or 821 according to the operator's policy.

In the case of collectively releasing the TCP connection as shown in FIG. 5, in step 813, the AS waits until a SIP 200 OK message for the SIP BYE request message is received. The SIP 200 OK message means that all TCP connections before the AS are successfully released. Thus, in step 815, the AS removes the states associated with the SIP session and the MSRP session.

If the states associated with the SIP session and the MSRP session are successfully removed, in step 817, the AS changes the Via header value of the SIP 200 OK message as specified in RFC 3261, and sets the SIP 200 to the first address of the Via header. Deliver the OK message. The first address of the Via header is the address of the SIP UA located just prior to the path of the SIP BYE request message.

On the other hand, when releasing the TCP connection step by step as shown in Figure 6, in step 821, the AS does not wait until the SIP 200 OK message is received, and removes the state associated with the SIP session and MSRP session. If the conditions associated with the SIP session and MSRP session are successfully removed, the AS in step 823 changes the Via header value of the SIP 200 OK message as specified in RFC 3261, and sets the SIP 200 to the first address of the Via header. Deliver the OK message.

After the SIP 200 OK message is delivered in step 817 or 823, the session release operation associated with the intermediate node AS is completed in step 819.

9 is a flowchart illustrating a session release operation performed at the opposite terminal when the session is released by one terminal according to an exemplary embodiment of the present invention. Here, the operation performed by UE # 2 in FIG. 5 and FIG. 6 is illustrated.

In step 901, the terminal waits to receive a SIP message. When the SIP BYE request message arrives in step 903, the UE removes states related to the SIP session and the MSRP session in step 905.

If the states related to the SIP session and the MSRP session are successfully removed, in step 907, the terminal transmits a SIP 200 OK message to the terminal that initially requested the session release as defined in RFC 3261.

After transmitting the SIP 200 OK response message, the UE releases the IP-CAN bearer in step 909. When the IP-CAN bearer is released, the connection with the P-CSCF is broken and the connection with the IP multimedia subsystem is terminated. Therefore, the session release operation of the terminal is terminated in step 911.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. In detail, in the present specification, the embodiments in the case where the terminals are located in the visited network have been described, but the present invention can be applied without significant modification even when at least one of the terminals is located in the home network. 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 operating 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 has the effect of providing a procedure of releasing an MSRP session when providing a session-based messaging service in an IP multimedia subsystem using SIP, so that the messaging service can be reliably terminated.

1 illustrates two messaging services provided in an IP multimedia subsystem, instant messaging and session-based messaging services.

2 illustrates a messaging service in an IP multimedia subsystem.

3 is a diagram illustrating the operation of SIP and MSRP.

4 is a message flow diagram when a single TCP connection is used without passing through an intermediate node in a situation where a calling terminal and a receiving terminal are serviced in a visited network according to a preferred embodiment of the present invention.

FIG. 5 is a message flow diagram illustrating a first embodiment of releasing a session when intermediate nodes participate in MSRP session establishment between an originating terminal and a receiving terminal. FIG.

6 is a message flow diagram illustrating a second embodiment of releasing a session when intermediate nodes participate in establishing an MSRP session between an originating terminal and a called terminal.

7 is a flowchart illustrating an operation when a terminal releases an MSRP session and terminates a session based messaging service of an IP multimedia subsystem according to a preferred embodiment of the present invention.

8 is a flowchart illustrating a session release operation performed in an intermediate node AS when a session is released by a terminal according to an exemplary embodiment of the present invention.

9 is a flowchart illustrating a session release operation performed at the opposite terminal when the session is released by one terminal according to a preferred embodiment of the present invention.

Claims (18)

A method of terminating a session-based messaging service performed through a message session relay protocol (MSRP) session formed through a session initiation protocol (SIP) session in an internet multimedia subsystem. One of two terminals performing the session-based messaging service without intermediate nodes transmits an end request message for terminating the session-based messaging service to the other terminal and sends the MSRP session related to the session-based messaging service. To turn it off, In response to the termination request message, the other terminal releases the MSRP session related to the session-based messaging service and transmits a response message to the one terminal. The method of claim 1, wherein the step of releasing the MSRP session, And removing TCP connection states and states related to the MSRP session. The method of claim 2, wherein the states related to the MSRP session include a session URL, a TR-ID, and a persistence flag, and the TCP connection states include a TCP port number, a TCP window size, and a TCP sequence number. The method. The method of claim 1, further comprising: releasing, by the other terminal, its own radio bearer related to the MSRP session after transmitting the response message to the one terminal; And receiving, by the one terminal, the response message and releasing its own radio bearer associated with the MSRP session. 2. The method of claim 1, further comprising the step of the one terminal and the other terminal maintaining radio bearers associated with the MSRP session for later use of the services of the Internet multimedia subsystem. The method of claim 1, wherein the one terminal and the other terminal are connected to a visited network to use the session-based messaging service. A method of terminating a session-based messaging service performed through a message session relay protocol (MSRP) session formed through a session initiation protocol (SIP) session in an internet multimedia subsystem. One of the two terminals performing the session-based messaging service through at least one intermediate node transmits a termination request message for terminating the session-based messaging service to the other terminal through the at least one intermediate node, Releasing the MSRP session associated with the session based messaging service; Releasing, by the other terminal, the MSRP session related to the session-based messaging service in response to the termination request message, and transmitting a response message to the one terminal through the at least one intermediate node; The at least one intermediate node releasing the MSRP session associated with the session based messaging service in response to the response message. The method of claim 7, wherein the step of releasing the MSRP session, And removing TCP connection states and states related to the MSRP session. 10. The method of claim 8, wherein the states related to the MSRP session include a session URL, a TR-ID, and a persistence flag, wherein the TCP connection states include a TCP port number, a TCP window size, and a TCP sequence number. The method. The method of claim 7, further comprising: releasing, by the other terminal, its own radio bearer associated with the MSRP session after transmitting the response message; And receiving, by the one terminal, the response message and releasing its own radio bearer associated with the MSRP session. 8. The method of claim 7, further comprising the step of the one terminal and the other terminal to maintain radio bearers associated with the MSRP session for later use of the services of the Internet multimedia subsystem. The method of claim 7, wherein the one terminal and the other terminal use the session-based messaging service in connection with a visited network. A method of terminating a session-based messaging service performed through a message session relay protocol (MSRP) session formed through a session initiation protocol (SIP) session in an internet multimedia subsystem. One of two terminals performing the session-based messaging service through at least one intermediate node sends a termination request message to the at least one intermediate node to terminate the session-based messaging service, and the session-based messaging. Releasing the MSRP session related to the service; After the at least one intermediate node forwards the termination request message to a subsequent intermediate node or the other terminal, the MSRP session related to the session-based messaging service is released in response to the termination request message, and the intermediate node of the previous stage is released. Or transmitting a response message to the one terminal. In response to the termination request message, the other terminal releasing the MSRP session related to the session-based messaging service, and transmitting a response message to the at least one intermediate node. The method of claim 13, wherein the step of releasing the MSRP session, And removing TCP connection states and states related to the MSRP session. 15. The method of claim 14, wherein the states related to the MSRP session include a session URL, a TR-ID, and a persistence flag, wherein the TCP connection states include a TCP port number, a TCP window size, and a TCP sequence number. The method. The method of claim 13, further comprising: releasing, by the other terminal, its own radio bearer associated with the MSRP session after transmitting the response message; And receiving, by the one terminal, the response message and releasing its own radio bearer associated with the MSRP session. 14. The method of claim 13, further comprising: maintaining, by the one terminal and the other terminal, radio bearers associated with the MSRP session for later use of the services of the Internet multimedia subsystem. The method of claim 13, wherein the one terminal and the other terminal use the session-based messaging service in connection with a visited network.