KR100757535B1 - Multimedia service method and system for division of application - Google Patents

Abstract

A multimedia service method capable of dividing applications and a device are provided to insert an application delimiter into a session setup request message for setting an SIP(Session Initiation Protocol) session, thereby dividing various kinds of services(applications) having different characteristics by using one CODEC(Coder Decoder). The first user agent selects a reception target(210). The first user agent determines an application type for communicating with the reception target(220). The first user agent transmits a generated invite message to a network server to demand session setup(230). The first user agent receives a response message to analyze the message, and conducts session connection according to the analyzed results(240). The first user agent confirms whether the set session is terminated(250). If so, the first user agent completes the session.

Description

MULTIMEDIA SERVICE METHOD AND SYSTEM FOR DIVISION OF APPLICATION

1 is a block diagram showing the structure of a general communication system for a multimedia service for applying the present invention;

2 is a block diagram schematically illustrating the structure of a multimedia service system (IMS) according to an embodiment of the present invention;

3 is a message configuration diagram showing an example of a session establishment request message (INVITE) format in the multimedia service system (IMS) standard for applying the present invention;

4 is a flowchart illustrating the operation of a first user agent according to an embodiment of the present invention;

5 is a flowchart illustrating a user registration and session establishment process in a multimedia service system according to an embodiment of the present invention;

6 is a flow diagram illustrating operation of a second user agent in accordance with an embodiment of the present invention.

The present invention relates to a multimedia service, and more particularly, to a message format configuration for identifying an application when performing an IP-based multimedia service, and a multimedia service method and apparatus using the same.

Recently, communication system is based on broadband wireless Internet service technology such as WCDMA and WiBro and IP, and is a next generation communication system that can provide various multimedia services away from voice-oriented services. Development is active.

However, the service development method in the existing circuit network or circuit network is difficult to develop a new service. Due to the nature of the line service, it was difficult to switch freely and switch freely, and for multimedia including various media, many restrictions were placed on the development and change of new applications such as allocating multiple lines at the same time or introducing a new multiplexing technique in the terminal. The development and operation cost a lot.

However, as next-generation networks evolve to provide multimedia services ranging from text to video such as voice e-mail over IP, there is a need for technology to implement various multimedia services and new services according to wired / wireless integration easily and cost effectively. Was done.

Accordingly, an IP multimedia subsystem (hereinafter referred to as IMS) based on a packet mobile network, which is part of a mobile communication network, is being developed.

The IMS is an open architecture that enables IP multimedia services in mobile, wired, and converged environments. It is based on Session Initiation Protocol (SIP) signaling and creates applications regardless of network or platform type. Can control and change, and can implement multimedia communication such as video or large data. In order to perform a multimedia service in such an IMS, a session for a multimedia service is connected using the SIP. In this case, a codec used for a service is defined using a Session Description Protocol (SDP) in an INVITE message.

However, since the conventional IMS defines only a codec, it is compulsory to provide one type of service for one codec configuration in a network or a terminal, so it is difficult to distinguish between various types of services having the same codec configuration. There is a problem. Accordingly, the conventional IMS has a ambiguity in providing a service through the UI of the terminal or the configuration of the intermediate server for generating the charging data, causing the difficulty of implementation.

Accordingly, an object of the present invention is to provide a multimedia service method and apparatus capable of classifying service types in a call connection in an IP multimedia subsystem (IMS).

Another object of the present invention is to provide an apparatus capable of classifying an application constituting a session establishment request message (INVITE) format for a SIP session connection configured by adding a separator for classifying application types.

Another object of the present invention is to provide a multimedia service method and apparatus capable of classifying an application by adding information for classifying an application to a session establishment request message (INVITE) for connecting a SIP session in a multimedia service.

The method for achieving the above object of the present invention, when the caller attempts to connect to the destination by selecting the called party, distinguishing the application when the service is executed in the session establishment request message for setting information to be used for the session Inserting an application identifier for the application; checking the location of the called party through the network server; transmitting the generated session establishment request message; and identifying the application identifier in the generated session establishment request message; It characterized in that it comprises a process of separating and executing.

The apparatus for achieving the above object of the present invention comprises a session establishment request message including a separator for distinguishing application types and information for session establishment in a multimedia service, and using the session establishment request message configured as a session. Sets; The session establishment request message includes a message start line and a header, and adds an application identifier for distinguishing the type of application when the sender and the caller connects the session to a request resource line (URI: Uniform Resource Identifier) of the request start line. A session initiation protocol (SIP) and a session description protocol (SDP) including detailed information on the multimedia service as a body area.

In addition, the apparatus may configure a session establishment request message including a delimiter for distinguishing application types and information for session establishment in a multimedia service, and establish a session using the configured session establishment request message; The session establishment request message includes a message start line and a header, and an application identifier for classifying an application type when a sender and a receiver connect a session in front of a content-type in a header area using a predetermined extension header. The Session Initiation Protocol (SIP), which is added, and a body area, includes detailed information on the multimedia service, and comprises a Session Description Protocol (SDP).

In addition, the apparatus may configure a session establishment request message including a delimiter for distinguishing application types and information for session establishment in a multimedia service, and establish a session using the configured session establishment request message; The session establishment request message includes a session initiation protocol (SIP) including a message start line and a header, and a body area, detailed information about the multimedia service, and uses a predetermined field when connecting a caller and a called party to a session. And a session description protocol (SDP) which adds an application identifier for classifying an application type. The application identifier is expressed by using the predetermined session information transmission or session attribute field. Is characterized in that it is inserted before the connection information field or the time field during which the session is active.

On the other hand, another apparatus for achieving the object of the present invention, a message generating unit for inserting the application delimiter for distinguishing the application type in a predetermined area of the session establishment request message during the session connection, and the network server via the Internet network The session setup request is determined by determining whether a session can be established with the called party according to a response from the network server, a transmitter / receiver which transmits a session setup request message, a storage which stores information included in the session setup request message, and a response from the network server. At least one user terminal comprising a control unit for controlling, receiving a session establishment request message through the network server in the case of the called party, checks the application identifier in the session establishment request message, and executes the service separately Is made of.

Another apparatus for achieving the objects of the present invention, the transmission / reception unit for transmitting and receiving a message for the session connection in conjunction with at least one user terminal via the Internet network, and the application in a predetermined area received from the calling user terminal A controller configured to analyze a session establishment request message including an application delimiter for distinguishing types, and determine whether the session can be established according to the analyzed result, and information about the at least one user terminal and information related to session establishment It includes a storage unit for storing, and if the session can be set, the network server for identifying the actual address of the called party and delivers the session establishment request message to the identified address.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals have the same reference numerals as much as possible even if displayed on different drawings. 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.

1 is a block diagram showing the structure of a general communication system for a multimedia service for applying the present invention.

In general, a communication system includes a wireless access network for mobile communication including a base station 20 performing wireless communication with a plurality of terminals 10 or a wired / wireless internet access network including a high speed wired / wireless internet terminal, a PC, and the like. Serving GPRS Support Node (SGSN) 30 for connecting a network 40, a network server 50 including a server such as user registration / change management, authentication, billing, and various applications. It consists of a service server (IMS server) 60 to manage. Here, a location registration server (not shown) that manages location information of the user may be included. It can be applied to such a general communication system to implement a system for a multimedia service. For example, if the system is a WCDMA system, the circuit switched area may be divided into a CS (Circuit Switched) Domain, a PS (Packet Switched) Domain, and a BC (BroadCast) Domain, and the IMS system includes elements constituting the PS Domain. Only interlocked. In addition, a gateway may be configured between the IP network and the WCDMA network.

Hereinafter, the multimedia service system according to the embodiments of the present invention will be described with an example of an Internet protocol multimedia subsystem (hereinafter referred to as IMS). First, a multimedia service system for providing a multimedia service will be described. A brief network structure will be described with reference to the accompanying drawings, and a concept for a multimedia service using a session initiation protocol (hereinafter referred to as SIP) in IMS will be described with reference to the accompanying drawings.

2 is a block diagram schematically showing the structure of an multimedia service system (IMS) according to an embodiment of the present invention.

IMS includes many functions and various implementation methods, but IMS can be classified into session control, gateway, and application functions. Here, the session control function is composed of servers that enable SIP services, and includes a call session control function (CSCF: Home Subscriber Server). Here, for the call session control function, a user terminal is registered and the SIP signaling is routed to an appropriate server. HSS is a database for managing subscriber information. User registration / change management, authentication, authorization, location, session routing, billing, etc. And store user information about it.

Referring to FIG. 2, the IMS 100 performs a multimedia service by communicating with a user 110 through a real time transmission protocol (RTP) through an IP network. Servers for enabling SIP services such as session connections are needed for such RTP communication, and a server for registering user information is required.

Accordingly, the IMS 100 includes a network server 120 including servers for performing the call session control function, and a location server (HSS) 130 for storing the user information. These servers 120 and 130 Are connected to the IP network and connect with users 110 via SIP. In other words, the IMS 100 is divided into user agents (UA # 1, UA # 2) 110a and 110b and servers 120 and 130 corresponding to user terminals, and the user agent (UA # 1). , UA # 2 (110a, 110b) is divided into a user agent client (UAC: User Agent Client) (111a, 111b) and a user agent server (UAS: User Agent Server) (112a, 112b). The UACs 111a and 111b send a request to the other party to join the session, and the UAS 112a and 112b returns an appropriate response message to the SIP request message.

On the other hand, the user terminals (UA # 1, UA # 2) (110a, 110b) is a transmitter / receiver (not shown) for transmitting the session establishment request message to a network server through the Internet network, the session establishment request It may be classified into a functional configuration such as a storage unit (not shown) that stores information included in a message, a message generation unit (not shown), and the user terminals UA # 1 and UA # 2 ( 110a and 110b may include other components for applying an embodiment of the present invention, such as a controller that performs overall control for session establishment.

The message generator generates a message for requesting session establishment (INVITE) and a message for establishing another session by inserting an application identifier for distinguishing application types in a predetermined area when a session is connected.

The network server 120 transmits / receives a message for connection to a session in connection with at least one user terminal through an internet network (not shown), and information and session for the at least one user terminal. It may be classified into a functional configuration such as a storage unit (not shown) and a controller (not shown) that stores information related to a setting, and may include other components for applying an embodiment of the present invention. have. Herein, the controller analyzes a session establishment request message in which an application separator is inserted into a predetermined region received from a calling user terminal, and determines whether the session can be established based on the analyzed result. Notifies the calling user terminal and performs overall control for session establishment.

In addition, the network server 120 may correspond to the network server 50 of FIG. 1, and may include a proxy server configured to forward SIP messages between a calling user and a called user. It may be divided into a redirect server that receives the session setup request message (INVITE) of the calling user and delivers information on the called user to the calling party. In addition, a location server and a registration server that store location information of the user may be included. However, it should be noted that in the IMS 100 according to the embodiments of the present invention, the location server is shown separately from the network server 120.

In order to perform multimedia service in IMS using SIP protocol, SIP session connection must be established. This SIP session is initiated by sending an INVITE message to the counterpart, i.e., the counterpart user agent. Within such INVITE message, the codec to be used for the session to be connected with the other party is defined to negotiate or specify the codec to be used when the service is executed. Next, an example of a session establishment request message (hereinafter referred to as INVITE) according to the IMS standard will be described with reference to FIG. 3.

3 is a message configuration diagram illustrating an example of a session establishment request message (INVITE) in the multimedia service system (IMS) standard for applying the present invention.

The INVITE may be divided into a SIP region 310 and an SDP region 320 as shown in FIG. 3.

Referring to FIG. 3, the SIP area 310 in the INVITE is divided into a SIP start line and a header part. The first item of the SIP start line is a SIP method, the next item is a request URI, and the last item is a SIP version. Indicates. In this case, the SIP method is 'INVITE', the request URI is 'sip: user2_public1@home2.net', for example, and the SIP version is 2.0. The next header part indicates the number of vias and the maximum forwards (for example, 70), and indicates user information, routing information, and the like in subsequent fields.

Subsequent SDP area 320 is the body of the SIP message here, INVITE, representing the description of the session. The description of this session may be divided into a single session description, at least one time, and a media description. The fields according to the present invention are well known to those skilled in the art, and a detailed description thereof will be omitted, and only the fields according to the embodiments of the present invention will be described.

The c field corresponding to the single session description indicates the IP address (IP6 5555 :: aaa :: bbb :: ccc :: ddd), and the m field corresponding to the media description indicates the media information (video 3400 RTP / AVP 98 99). ), Audio (audip 3456 RTP / AVP 97 96). Here, the c field is used as connection information.

Next, a method for distinguishing an application by newly generating an INVITE message according to an embodiment of the present invention is described in the above-described INVITE message according to the IMS standard, and a multimedia service is performed by establishing a session based on the generated INVITE message. The process of doing this will be described in detail with reference to the accompanying drawings. First, a method of using the SIP URI of the generated INVITE message to generate a new INVITE message and distinguishing an application according to the first embodiment of the present invention will be described.

As shown in FIG. 3, the UIA (Uniform Resource Identifier, hereinafter referred to as URI) expressed in the second item of the INVITE SIP start line is a representation of a user and is configured as 'sip: user ID @ server name'. In this case, the 'server name' indicates a domain address, and a larger area is displayed as going backwards.

Therefore, in the first embodiment of the present invention, such a SIP URI may be implemented as 'server name' = 'application type.service domain'. According to this implementation, for example, the request URI (sip :) including the SIP receiver URL in the second entry of the SIP start line in the INVITE message of FIG. It can represent: user2_public1@VTO.home2.net. If the WIPI is used, for example, sip: may be represented by adding an application ID (a8cd0100) after the WIPI. That is, it can be expressed as sip: user2_public1@WIPIa8cd0100.home2.net.

As described above, in the first embodiment of the present invention, a method for distinguishing applications by adding a delimiter for distinguishing the application type to the SIP URI in the INVITE, that is, expressing the 'server type' as 'application type. Service domain' In the second embodiment of the present invention, a method of distinguishing applications by inserting a separator for distinguishing application types into a SIP header will be described.

According to the second embodiment of the present invention, the first user agent which is the originating user inserts a delimiter for distinguishing application types into the SIP header of the SIP 210 shown in FIG. Here, SIP can use a user header similar to HTTP, and user header is an extension-header so that it does not overlap with an existing header. Accordingly, the first user agent uses 'm _...' or 'X _...'. For example, when using 'X _...', the application is expressed as 'X-Appl-type'. Insert a header. As shown in Table 1, it is preferable to add such an application classification header to the front of the content represented in FIG. 1, whereby the sender's user agent is set to 'X-Appl-type: VT; version = 0' and You will create a new INVITE with a separator to distinguish the same application type.

… Contact: X-Appl-type: VT; version = 0 Content-Type: application / sdp…

Meanwhile, while the second embodiment of the present invention described above has described a method for distinguishing applications by inserting into a SIP header, in the third embodiment of the present invention, a session description protocol (hereinafter, referred to as SDP) corresponding to a SIP body in INVITE is described. The method for classifying applications by adding a delimiter for classifying application types in the description will be described.

According to the third embodiment of the present invention, the first user agent, which is the originating user, sends an 'i =' field or a session attribute for transmitting session information in the SDP area 220 shown in FIG. By adding the type of application to be distinguished using the 'a =' field that transmits, the sender's user agent generates a new session establishment request message (INVITE). As shown in <Table 2> and <Table 3>, the 'i =' field is preceded by the connection information field ('c ='), and the 'a =' field is a time field ('t =') at which the session is activated. ) Before the.

… s =-i = appl-type: VT 0 c = IN IP6 5555 :: aaa: bbb: ccc: ddd…

… c = IN IP6 5555 :: aaa: bbb: ccc: ddd a = appl-type: VT 0 t = 0 0...

The delimiter for classifying the application type may include, for example, VT: video call, voice-call: voice call, WIPI: WIPI application, Video-Chat: video chat, and the like. In addition, the video phone represented by the VT may express the basic quality as 0 and the high quality as 1, and the WIPI application may express a WIPI application ID to be used or data to be delivered.

The newly generated INVITE message according to the embodiments of the present invention as described above can distinguish various kinds of applications in the multimedia service. Next, a process for a multimedia service using the newly generated INVITE message and a process of connecting a session for performing such a multimedia service communication will be described in detail with reference to the accompanying drawings.

4 is a flowchart illustrating the operation of a first user agent according to embodiments of the present invention.

Referring to FIG. 4, in step 210, the first user agent 110a serving as the originator selects a call destination. In operation 220, the first user agent 110a determines a method of communicating with the called party. That is, a new INVITE for generating applications is generated by applying at least one of the embodiments of the present invention. That is, the application (media) type is inserted into the SIP URI, the SIP header or the SDP in the INVITE.

In operation 230, the first user agent 110a transmits the generated INVITE to the network server 120 to request session establishment. Accordingly, the network server 120 checks the location information on the requesting SIP URI and transmits INVITE to the second user agent 110b, which is a call destination according to the confirmed location information, and receives a response. Send a response message. In operation 240, the first user agent 110a receives and analyzes the response message and then connects to the session according to the analysis result. If the analysis result is a redirection, the session is reset. If the session content is different from the transmitted content, the session is reset by rejecting the session or changing the session content.

In operation 250, the first user agent 110a checks whether the established session is terminated. As a result, when the session release request of the first user or a message about the session release is received from the second user agent, the session is terminated.

On the other hand, in step 250, if there is no session release request, in step 260, the first user agent 110a performs a multimedia service through real-time transmission protocol (RTP) communication according to the set session.

In this process, the registration request, session establishment and resetting processes such as steps 220 to 250 will be described in detail.

5 is a flowchart illustrating a session establishment process in a multimedia service system according to embodiments of the present invention, and FIG. 6 is a flowchart illustrating a session reset process in a multimedia service system according to embodiments of the present invention.

Referring to FIG. 2, the network server 120 receives the REGISTER request including the SIP URI from the first user agent 110a, and thus the first and second user agents 110a and 110b. Can act as a register server to track location. When the network server 120 receives the session connection request from the first user agent 110a through INVITE, the network server 120 determines whether the session can be established according to a call processing policy and responds.

Referring to FIG. 5, the first user agent 110a performs a session connection with the second user agent 110b to perform a multimedia service. Accordingly, in operation 311, the first user agent 110a performs a session connection. Transmits the newly created session establishment request message (INVITE) to the network server 120.

Then, according to an embodiment, the network server 120 may include a SIP URI (sip :) or a SIP header (X-Appl-type: VT; version = 0) or an SDP field (i = appl-type :) included in the INVITE message. In VT 0, a = appl-type: VT 0), check the delimiter to distinguish the application type, and check the user information through the SIP start line and header information. In operation 312, the network server 120 requests user location information registered in advance by the second user agent 110b to identify the location of the second user, and receives the user location information requested in step 313. In step 314, the network server 120 transmits the received INVITE to the second user agent 110b according to the location information of the second user. Then, the second user agent 110b receives a SIP URI (sip :) or SIP header (X-Appl-type: VT; version = 0) or an SDP field (i = appl-type: VT 0, a) in the received INVITE. = appl-type: VT 0) confirms that the application identifier is a video telephony service (VT) and executes it to classify applications for services on IMS and make mutual calls with audio and media expressed in SIP text. While performing a video telephony service, a video / audio transmission service similar to a PTT can be performed with the same codec configuration.

Thereafter, when the network server 120 receives the success confirmation message 200 OK from the second user agent 110b in step 315, the network server 120 receives the success confirmation message 200 OK received in step 316. To pass). Accordingly, in steps 317 and 318, the first user agent 110a transmits a response message (ACK) to the second user agent through the network server 120. At this time, the network server 120 checks the session establishment request message (INVITE) and enforces the charging policy for the divided applications. For example, if another video / audio transmission service in the PTT format is available together with the video call service using the same codec, the video call service should be time charged for the entire time of the call. Only charge for time, video should be time charged, voice should be packet charged.

Therefore, the network server 120 may distinguish the application (service) type by analyzing the received INVITE to clearly distinguish how the session is charged and which application should be operated in the user terminal. In addition, the network server 120 may check and process whether the user is divided into services and subscribed / unsubscribed, that is, whether the service is available.

If there is a change of information of the second user (inconsistency due to location movement, non-subscription of the service, etc.), the first user agent 110a transmits the INVITE to the network server 120 in step 311. The network server 120 receives a response message notifying the failure of the session establishment. Accordingly, the first user agent 110a checks the fraud response message and requests a session establishment again from the network server 120 when a session reset is required. Accordingly, when the first user agent 110a knows the address of the network server 120 or the call destination again, the first user agent 110a directly transmits INVITE to the call destination.

Next, an operation of the second user agent, which is a call destination after being connected through such session setup, will be described with reference to the accompanying drawings.

6 is a flowchart illustrating the operation of a second user agent in accordance with embodiments of the present invention.

Referring to FIG. 6, in operation 510, the second user agent 110b, which is a call destination, receives an incoming call notification message after a session connection with the first user agent 110b is made. Then, in step 520, the second user agent 110b checks the current terminal situation according to the bandwidth and the type of the call to check whether the call is possible. As a result, when the call processing is impossible due to a poor terminal situation, the operation is terminated. Otherwise, in operation 530, the second user agent 110b determines the type of the call, that is, the service (application) type, and in step 540. Run a service (application). Such service types include WIPI applications, video telephony, voice telephony, video PTT, and video chat.

Then, in step 550, the user is informed that the incoming call is received through vibration, sound, and announcement.

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. 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 the equivalents of the claims.

As described above, the present invention can distinguish various kinds of services (applications) having different characteristics by using one codec by inserting an application separator in a session establishment request message (INVITE) for establishing a SIP session. The conventional IMS has an effect that can be easily implemented because it can overcome the ambiguity in the configuration of the intermediate server for determining the generation of billing data and whether or not the call connection or providing the service through the UI of the terminal.

Claims (17)

When the caller selects a called party and attempts to connect to the called party, the request resource ID of the Session Initiation Protocol (SIP) in the session establishment request message (INVITE) that sets information to be used for the session. Inserting an application delimiter for distinguishing an application when the service is executed into any one of a header area and a body area; and inserting an application delimiter using a predetermined extension area into the header area and a predetermined area into the body area. Insert application separators using fields-and, Checking the location of the called party through the network server and transmitting the generated session establishment request message; And identifying the application identifiers in the generated session establishment request message to separate and execute the applications. The method of claim 1, The application delimiter is expressed using the predetermined extension header, and the header of the expressed application delimiter is inserted into the front of the content (Content-Type). The method of claim 1, The application identifier is expressed using the predetermined session information transmission or session attribute field, and the expressed application identifier field is inserted in front of the connection information field or the time field in which the session is activated. . Configuring a session establishment request message including a separator for distinguishing application types and information for session establishment in a multimedia service, and establishing a session using the configured session establishment request message; The session establishment request message is The Session Initiation Protocol (SIP) includes a request identifier (UIP) and an application identifier added in front of the content-type of the header area to distinguish the types of applications when the sender and the receiver connect the session. Multimedia service device capable of distinguishing applications, characterized in that. The method of claim 4, wherein And an application identifier in front of a content-type of the header area using a predetermined extension header. Configuring a session establishment request message including a separator for distinguishing application types and information for session establishment in a multimedia service, and establishing a session using the configured session establishment request message; The session establishment request message is A body region, including session information protocol (SDP) including detailed information on the multimedia service and adding an application identifier for classifying an application type by using a predetermined field when connecting a caller and a called party. Multimedia service device capable of distinguishing applications. The method of claim 6, The application identifier is expressed using the predetermined session information transmission or session attribute field, and the expressed application identifier field is inserted in front of the connection information field or the time field in which the session is activated. . Message generation unit for inserting the application identifier for distinguishing the application identifier in any one of the Session Initiation Protocol (SIP) request Uniform Resource Identifier (URI), the header area and the body area in the session establishment request message- Of these, an application separator is inserted into the header area using a predetermined extended area, and an application separator is inserted into the body area using a predetermined field. A transmission / reception unit for transmitting the session establishment request message to a network server through the internet network; A storage unit which stores information included in the session establishment request message; And a controller for controlling session establishment by determining whether to establish a session with a called party according to a response from the network server. In the case of the called party, the session establishment request message is received through the network server, the application identifier in the session establishment request message is identified, and the services are distinguished and executed. Service device. The method of claim 8, And the application identifier is expressed in the predetermined extension header, and the header of the expressed application identifier is inserted in front of a content type. The method of claim 8, And the message generator inserts an application identifier into a body region of a session initiation protocol (SIP) in the session establishment request message (INVITE) using a predetermined field. delete delete delete delete delete delete delete

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