KR100535241B1 - Call/session redirecting method using session initiation protocol when the called party is no answer - Google Patents

Abstract

The present invention discloses a SIP protocol-based non-response call switching method for switching a call to another preset terminal when there is no response for a predetermined time. In the conventional call system, all communication between each system component must use the standard VOIP protocol for call control. Therefore, various programs for providing additional services such as call setup function and call transfer service of the standard VOIP protocol are provided to the user terminal. The program size is increased because it must be embedded, and of course, the complicated call processing process, which is a disadvantage of the standard VOIP protocol, increases the time required for call setup and additional service, resulting in a waste of network resources. The present invention can further improve the network environment because the service for automatically switching to a third destination terminal which is automatically set when no response is performed by simple SIP message exchange.

Description

CALL / SESSION REDIRECTING METHOD USING SESSION INITIATION PROTOCOL WHEN THE CALLED PARTY IS NO ANSWER}

The present invention relates to a non-answer call transfer method based on the Session Initiation Protocol (SIP), and more particularly, a call terminal is not connected to a call for a predetermined time using a SIP protocol message. In this case, the present invention relates to a SIP protocol-based non-response call switching method for providing a service for switching a call to a third predetermined terminal.

With the development of computer technology and the general use of the Internet due to the emergence of the powerful application of the web (WWW), the use of the Internet communication network which is cheaper to call is increasing.

Internet communication network converts the analog voice signal into a predetermined voice data packet and transmits it to the counterpart through the Internet established for data exchange between computers, converts the voice data transmitted from the counterpart into an analog voice signal and outputs it to the user. In order to enable voice communication, the Internet communication network uses a PC-to-pc method in which all users who make a call use a PC, and a user uses a PC according to the type of a terminal used by the user. However, other users can be divided into a PC-to-phone method using a regular phone and a phone-to-phone method using both phones.

Both of these methods are methods in which one user or both users use a telephone connected to an existing telephone network.

In the conventional call system, all communication between each system component must use the standard VOIP protocol for call control. Therefore, various programs for providing additional services such as call setup function and call transfer service of the standard VOIP protocol are provided to the user terminal. Since the size of the program is increased, the complicated call processing process, which is a disadvantage of the standard VOIP protocol, increases the time required for call setup and additional service, resulting in a waste of network resources.

Accordingly, the present invention was created to solve the above problems, and the present invention provides a network environment because the service for automatically switching to a third preset terminal preset by the called terminal when no response is performed only by exchanging SIP messages. The purpose of the present invention is to provide a call switching method when no response based on SIP protocol can be further improved.

According to the first aspect of the present invention for achieving the above object, a SIP protocol-based non-response call switching method includes:

After registering in the SIP network through the called terminal and activating the call transfer service when there is no response, after setting the third called terminal information, if there is no response from the called terminal for a predetermined time, the call is transferred to the third called terminal set by the called terminal. In the SIP protocol-based non-response call switching method,

a) sending, by the calling terminal, a session start request message according to the SIP protocol to the calling call processing server and the called call processing server in order to make a call connection to the called terminal;

b) After the step a) is executed, a service triggering procedure based on the service profile is performed through the incoming call processing server receiving the session start request message, and the session start request message to execute the service is transmitted to the application server. Sending a session start request message for a call connection to the called terminal;

c) detecting, via the incoming call processing server, a SIP protocol message indicating that the ring is provided from the called terminal by step b) and transmitting the SIP protocol message to the application server and the calling terminal, respectively;

d) starting a timer of an application server that has received a SIP protocol message indicating that it is ringing by step c);

e) checking whether a response message for accepting a call connection has been received through the application server while the timer of step d) is running, and if not, sending a session start request message between the application server and the incoming call processing server; Terminating a session start request message for a call connection between the called terminal and the called call processing server through a cancellation and session start request message transmission ending procedure;

f) through the originating call processing server, a SIP protocol message indicating that the session start request message for the call connection between the called terminal and the called call processing server is terminated and the call is output from the application server through step e); Transmitting to a terminal; And

g) transmitting the session start request message from the incoming call processing server to the third called terminal through the third incoming call processing server according to the location information of the third called terminal provided through the second location server after executing step f). It is characterized by consisting of a step of making a call.

Preferably, in the SIP protocol-based non-answer call switching method according to the first aspect of the present invention, the transmission cancellation procedure of the session start request message between the application server and the incoming call processing server of step e),

e-1) transmitting, by the incoming call processing server, a SIP protocol message (CANCEL) to stop transmitting the session start request message provided to the called terminal to the called call processing server; And

e-2) receiving a response message (200 OK) for receiving a SIP protocol message (CANCEL) provided from the incoming call processing server (205) of step e-1);

e-3) SIP protocol message (CANCEL) to stop transmission of the session start request message provided from the incoming call processing server to the called terminal through the incoming call processing server receiving the SIP protocol message to cancel the transmission of the session start request message. Transmitting to the called terminal;

e-4) receiving the response message (200 OK) in response to the reception of the SIP protocol message (CANCEL) provided to the called terminal in e-2), and transmitting it to an application server,

The session start request message transmission end procedure between the application server and the incoming call processing server may be performed by:

e-5) A SIP protocol message (487 REQUEST TERMINATED) indicating that the request for the session start request message (INVITE) has been terminated by the SIP protocol message (CANCEL) received through step e-4) to the incoming call processing server. Transmitting;

e-6) transmitting an acknowledgment message (ACK) to the called terminal to the SIP protocol message (487 REQUEST TERMINATED) provided from the incoming call processing server (205) through step e-5);

e-7) transmitting to the application server that a SIP protocol message (487 REQUEST TERMINATED) received through step e-6) has been reached; And

e-8) characterized in that it comprises the step of transmitting a response message (ACK) for the SIP protocol message (487 REQUEST TERMINATED) transmitted through the e-7) to the incoming call processing server.

In the SIP protocol-based non-response call switching method according to the first aspect of the present invention, step g) includes:

After the execution of step f), when the third destination terminal is to be routed through the circuit-switching network by analyzing the information of the third destination terminal through the incoming call processing server, the calling terminal and the public telephone network are connected by connecting a call channel through a gateway. The feature of the call connection between the third terminating terminal of the scheme.

Also, preferably, in the SIP protocol-based non-answering call switching method according to the first aspect of the present invention, the step f) includes a call connection between the called terminal and the called call processing server through step e). Terminating a session start request message for transmitting a SIP protocol message indicating an address change output from the application server to an originating terminal through an incoming call processing server and an outgoing call processing server;

The step g) is characterized in that it is provided to transmit to the user whether to redial the call according to the third destination terminal information to be forwarded included in the SIP protocol message informing the address change in step f),

Here, in step g), when the third destination terminal is a SIP UAL, it is provided to generate and transmit a session start request message confirming the address of the third destination terminal from the originating terminal, the third destination terminal In the case of the UAL of the public telephone network, the circuit switched mobile telephone function of the calling terminal is automatically driven to set up a call to the third called terminal. When the third called terminal is an HTTP URL, the Internet browser of the calling terminal is automatically set. Drive to set up a session requesting an incoming call to the third destination terminal address, and when the third destination terminal is an e-mail address, an e-mail program of the calling terminal is provided to drive.

In addition, the SIP protocol-based non-response call switching method according to the second aspect of the present invention,

h) sending, by the calling terminal, a session start request message according to the SIP protocol to the called terminal through the calling call processing server and the called call processing server in order to make a call connection to the called terminal;

i) transmitting a SIP protocol message indicating that the ring is provided from the called terminal to the called call processing server and the calling terminal after executing step h);

j) A service triggering procedure based on a service profile is performed through the incoming call processing server that receives the SIP protocol message indicating that the ring is in progress through step i), and a session start request message to execute the service is sent to the application server. Starting a timer after being sent;

k) checking whether a response message for accepting a call connection is received from the called terminal while the timer is operated by step j), and canceling the transmission of the session start request message between the called call processing server and the called terminal if not received. Executing a session start request message transmission end procedure;

l) after the execution of step k), after the session start request message for executing the call transfer service through the incoming call processing server is transmitted to the application server, the SIP protocol message indicating that the call is output from the application server is recalled. Transmitting to the calling terminal through an incoming call processing server and the outgoing call processing server, and transmitting a session start request message for call transfer to the incoming call processing server; And

m) after the execution of step l), according to the location information of the third destination terminal provided through the second location server, a session start request message from the destination call processing server to the third destination terminal through the third destination call processing server; It is characterized by consisting of the step of transmitting a call.

According to the present invention, a separate application server that performs a call transfer service according to the SIP protocol is installed, and in advance, when an incoming terminal is unresponsive for a predetermined time by exchanging a simple SIP message between an originating terminal, an incoming call processing server, and an application server. By switching the call to the set third destination terminal, the network environment can be further improved.

Hereinafter, the present invention will be described in more detail with reference to the following examples.

1 is a diagram showing the configuration of a SIP protocol-based non-response call switching apparatus to which the present invention is applied. As shown in FIG. 1, the SIP protocol-based call switching apparatus according to the present invention provides information on a caller and a called terminal. The originating terminal 201 for transmitting, the first location server 202 for providing the location information of the called terminal, and the originating call processing server 203 connected to the originating terminal 201 and the first location server 202; Include.

The call switching device includes an incoming call processing server 205 connected to the outgoing call processing server 203 through an IP network, a called terminal 207 connected to the incoming call processing server 205, and the originating terminal. The second location server 210 providing the location information of the application server 209 and the third destination terminal 213 requesting call transfer when there is no response of the called terminal for the predetermined time when the call is sent. The receiver further includes a terminating call processing server 211 and a third terminating terminal 213 connected to the third terminating terminal, the third terminating terminal 213.

And, if the call transfer to the third destination terminal 213 is used as a public telephone network (PSTN / PLMN) is provided to be written through the gateway (MGCF) 251.

In the SIP protocol-based non-answer call switching device to which the present invention configured as described above is applied, unlike the existing call switching service, the call switching function of the user terminal is based on the SIP protocol-based outgoing call processing server 203 and SIP. The protocol-based incoming call processing server 205, the application server 209, and the third incoming call processing server 211 are processed.

Here, SIP is a text-based protocol, and can be divided into a request and a response message. The request message includes an INVITE that starts a session, an ACK that is a confirmation message for a response, a BYE that ends a session, a CANCEL that cancels a search and rings a ring, a register that registers an address in a server, and other options. The response message is identified by three digits, and the representative message is 180 RING indicating that the destination terminal is ringing, 200 OK indicating that the other party accepts the call connection, and 486 BUSY indicating that the other party is busy. , 302 MOVE to indicate that the other party's address has changed, 403 FORBIDDEN to indicate that the sender is denied, 487 REQUEST TERMINATED to indicate that the request has been terminated, and 181 CALL FORWARDED to indicate that the request has been transferred. Since the definition is set by an operator or an individual, it can be changed. First Embodiment: When a call is transferred to a third destination terminal through an IP network using an application server having a timer.

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2 is a flowchart illustrating a call switching process when no response based on a SIP protocol according to an embodiment of the present invention.

In FIG. 2, a request for starting a section including information required for call connection, that is, a telephone number (called terminal information) of a called terminal to be called according to the SIP protocol and its network information (ie called terminal information). The message INVITE is output from the calling terminal 201 via step 301.

The outgoing call processing server 203 that has received the session start request message INVITE outputted through the step 301 is the outgoing call processing server 203 from the first location server 202 to the called terminal 207. Proceed to step 303 receiving the location information of the step 305, the step 305 is a session start request message according to the SIP protocol according to the location information of the called terminal 207 (INVITE ) Is transmitted to the incoming call processing server 205 through the IP network.

The incoming call processing server 205 receiving the session start request message (INVITE) provided from the outgoing call processing server 203 through the step 305 proceeds to step 307, and the step 307. Analyzes the session start request message (INVITE) received through step 305 to check whether the called terminal 205 is subscribed to the call transfer service and, if subscribed, triggers a service based on the contents of the call transfer service profile. The procedure is performed to send a session start request message to the application server 209 to execute the service.

The service triggering procedure is executed based on initial Filter Criteria information in the service profile, where initial Filter Criteria information refers to all mechanisms corresponding to a service triggering criterion previously defined in connection with service provision of a subscriber.

After execution of the step 307, the incoming call processing server 205 proceeds to step 309, where step 309 sends a session start request message (INVITE) according to the SIP protocol to the called terminal 207. do.

Meanwhile, the receiving terminal 207 receiving the session start request message (INVITE) through the step 309 generates a ring signal and then rings the SIP protocol message 180 ring indicating that the ring is in progress. The process proceeds to the step 311 of transmitting to the call processing server 205 and proceeds to step 313, where step 313 is a SIP of the incoming call processing server 205 provided from the called terminal 207. A protocol message 180 RING is provided to the application server 209.

When the execution of step 313 is completed, the process proceeds to step 315, where step 315 sends a SIP protocol message 180 RING of the incoming call processing server 205 to the outgoing call processing server 203. It provides to the calling terminal 201 through.

The application server 209 which has received the SIP protocol message 180 RING through the step 315 receives a SIP protocol message 180 RING, and then, after receiving the SIP protocol message 180 RING, the application server 209 receives a predetermined time by the operation of the timer operated by the step 307. It checks if the elapsed time and executes step 317 of executing logic for providing a call transfer service when a predetermined time elapses.

Here, the call transfer service logic is implemented in a language such as a call processing language (CPL), and means code including service subscriber information, a subscription service type, an operation mode of an application server, a service application condition, and an application result. .

In response to the execution of the call transfer logic, the application server 209 proceeds to step 319 to stop transmission of the session start request message INVITE that was provided from the incoming call processing server 205 to the called terminal 207. The SIP protocol message CANCEL is transmitted to the incoming call processing server 205, and a response message 200 OK for receiving the SIP protocol message CANCEL provided from the incoming call processing server 205 is received.

In addition, the incoming call processing server 205 receiving the SIP protocol message (CANCEL) SIP protocol to stop the transmission of the session start request message (INVITE) provided from the incoming call processing server 205 to the destination terminal 207. Transmitting the message CANCEL to the called terminal 207, receiving a response message 200 OK for receiving the SIP protocol message CANCEL provided to the called terminal 207, and transmitting it to the application server 209 ( Proceed to 321).

On the other hand, after the execution of the step 321 proceeds to step 323, step 323 is a request of the session start request message (INVITE) by the SIP protocol message (CANCEL) received through the step 321 Send a SIP protocol message (487 REQUEST TERMINATED) indicating that it has been terminated to the incoming call processing server 205, and respond to the SIP protocol message (487 REQUEST TERMINATED) provided from the incoming call processing server 205 (ACK). Is transmitted to the called terminal 207.

When the reception of the SIP protocol message 487 REQUEST TERMINATED is completed through the step 323, the process proceeds to the step 325, and the step 325 indicates that the SIP protocol message 487 REQUEST TERMINATED has been received. And sends a response message (ACK) provided from the application server 209 to the incoming call processing server 205.

On the other hand, the application server 209 that receives the SIP protocol message (487 REQUEST TERMINATED) has been received proceeds to step 327, the step 327 is a SIP protocol message (181 CALL FORWARDED) to switch the call Is transmitted to the incoming call processing server 205.

The incoming call processing server 205 receiving the SIP protocol message 181 CALL FORWARDED transmits the message to the calling terminal 201 through the outgoing call processing server 203 (step 329) (step 331).

Meanwhile, a session start request message (INVITE) according to the SIP protocol of the application server 209 is sent to the incoming call processing server 205 in order to request a call setup from the third destination terminal set from the application server 209. The incoming call processing server 205 is sent (step 333) and receives this session start request message (INVITE).

The step 335 is a message for requesting the start of a session for call setup according to the location information of the third terminating terminal 210 of the second location server 210 received through the step 334 (INVITE). ) Is transmitted to the third incoming call processing server 211, and the third incoming call processing server 211 which has received this message (INVITE) proceeds to step 337 to release this session start request message (INVITE). It is provided to the called terminal 213 of three.

Here, the procedure of steps 319 to 331 and the procedure of steps 331 to 337 are independent processes, and thus may be simultaneously executed.

In addition, a voice channel is opened by opening a call channel between the calling terminal 201 and the third called terminal 213 by exchanging SIP protocol messages indicating normal ring generation and call call connection. When the call is transferred to the third destination terminal using the public telephone network

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3 is a flowchart illustrating a call switching process when no response based on a SIP protocol according to another embodiment of the present invention.

In Fig. 3, the same parts as those in Fig. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

Referring to FIG. 3, the processes from steps 301 to 331 are the same as those of FIG. 2.

When the call is to be written through the circuit switched network by analyzing the information of the third destination terminal of the session start request message provided from the application server 209 through the step 331, the interworking function of the IP network and the circuit switched network in the network is performed. In step 351, a session start request message (INVTIE) is transmitted to a media gateway control function (MGCF).

The gateway 251 receiving the session start request message through the step 351 proceeds to step 353 and converts the SIP protocol message of the IP network (packet network) to an SS7 protocol such as an ISUP of the circuit network. The converted ISUP protocol message IAM is then routed to the third destination terminal 213 through the public telephone network PSTN 253 (step 355). Third embodiment: When a call is transferred to a third destination terminal having an e-MAIL address

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4 is a flowchart illustrating a call switching process when no response based on a SIP protocol according to another embodiment of the present invention.

In Fig. 4, the same parts as those in Fig. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

Referring to FIG. 4, the processes from steps 301 to 325 are the same as those of FIG. 2.

The application server 209 receiving the response message 200 OK for the SIP protocol message 487 REQUEST TERMINATED indicating that the transmission of the session start request message is terminated through the step 325 proceeds to step 361, and the step ( 361 sends a SIP protocol message 302 MOVED TEMPORARILY indicating the change of address to the incoming call processing server 205.

The incoming call processing server 205 receiving the SIP protocol message 302 MOVED TEMPORARILY indicating the change of address through the step 361 receives a confirmation message 200 OK for the SIP protocol message 302 MOVED TEMPORARILY indicating the change of the address. Send to application server 209 (step 363).

The incoming call processing server 205 receiving the SIP protocol message 302 MOVED TEMPORARILY indicating the change of address through the step 361 sends the SIP protocol message 302 MOVED TEMPORARILY indicating the change of the address to the originating call processing server 203. ACK to the calling terminal 201 (step 365) (step 367), and the acknowledgment message (ACK) for the SIP protocol message 302 MOVED TEMPORARILY indicating address change sent via these steps 363 and 365. Are respectively transmitted (step 369) (step 371).

In step 367, the originating terminal 201 receiving the SIP protocol message 302 MOVED TEMPORARILY indicating the change of address is automatically redialed according to the information of the third called terminal to be transferred (step 373).

In this case, when the third called terminal is a SIP Uniform Resource Locator (URL URL), a session start request message for confirming an address of the third called terminal is generated and transmitted from a calling terminal, and the third called terminal is a URL of a public telephone network. Is set, the call is set to the third destination terminal by driving the circuit switched mobile telephone function of the calling terminal.

In addition, when the third destination terminal 213 is an HTTP URL (Internet home page), the Internet browser in the calling terminal 201 is automatically driven to redial the call, and the call is made when the third destination terminal is e-MAIL. The e-MAIL program in the terminal 201 is driven to transmit the call to the user. If the user requests a redial, the call is redialed. Fourth Embodiment: When a call is transferred to a third called terminal through an IP network by using an incoming call processing server and an application server having a timer.

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5 is a flowchart illustrating a call switching process when no response is based on the SIP protocol according to another embodiment of the present invention.

In FIG. 5, a request message for requesting to start a section including information required for call connection, that is, a telephone number (destination address) of a called terminal to be called according to the SIP protocol and its network information (that is, calling terminal information). INVITE is output from the calling terminal 201 through step 401.

The outgoing call processing server 203 that has received the session start request message INVITE outputted through the step 401, the outgoing call processing server 203 receives the incoming terminal 207 from the first location server 202. After the process proceeds to step 403 where the location information is received, the process proceeds to step 405, in which step 405 is a session start request message according to the SIP protocol according to the location information of the called terminal 207 (INVITE). ) Is transmitted to the incoming call processing server 205 through the IP network.

The incoming call processing server 205 receiving the session start request message (INVITE) provided from the outgoing call processing server 203 through the step 405 proceeds to step 407 and the step 407. Analyzes the session start request message INVITE received through step 405 and transmits the session start request message INVITE to the called terminal 207.

The receiving terminal 207 receiving the session start request message (INVITE) through the step 407 generates a ring signal and then sends a SIP protocol message (180 RING) indicating that the ring is in progress. 205 and steps 409, 411, and 413 for transmitting to the calling terminal 201 through the outgoing call processing server 203 in step 415.

Meanwhile, the incoming call processing server 205 receiving the SIP protocol message 180 RING indicating that the ring is in the ring through step 409 checks whether the called terminal 205 has subscribed to the call transfer service. In case of subscription, a service triggering procedure based on the service profile content is performed to start the timer (step 415).

Here, when the response message 200 OK for accepting the call connection is not received while the timer is running, the timer of the incoming call processing server 205 is terminated (step 417).

Thereafter, the incoming call processing server 205 transmits a SIP protocol message CANCEL to stop the transmission of the session start request message INVITE, which has been provided to the called terminal 207, to the incoming call processing server 205. Receive a response message 200 OK for receipt of the SIP protocol message CANCEL provided from the call processing server 205 (step 419).

On the other hand, after the execution of the step 419 proceeds to step 421, the step 421 is a request of the session start request message (INVITE) by the SIP protocol message (CANCEL) received through the step 321 Sends a SIP protocol message (487 REQUEST TERMINATED) indicating that the call is terminated to the incoming call processing server 205, and responds to the SIP protocol message (487 REQUEST TERMINATED) provided from the incoming call processing server 205 (ACK). ) Is transmitted to the called terminal 207.

After execution of step 421, the incoming call processing server 205 proceeds to step 423, where step 423 is a session start request message (INVITE) according to the SIP protocol for executing call transfer service logic. Is transmitted to the called terminal 207.

In this case, since the procedure of steps 419 and 421 and the procedure after step 423 are independent processes, they may be executed in parallel.

Upon receiving the session start request message for executing the call transfer logic, the application server 209 proceeds to step 425 to execute logic for call transfer.

The application server 209 then proceeds to step 427, where step 427 processes the incoming call processing server 205 and the outgoing call with a SIP protocol message 181 CALL FORWARDED to switch the call. Sending to the calling terminal 201 via the server 203 (step 426) (427) (429).

Meanwhile, a session start request message (INVITE) according to the SIP protocol of the application server 209 is sent to the incoming call processing server 205 in order to request a call setup from the third destination terminal set from the application server 209. The incoming call processing server 205 which has been sent (step 431) and has received this session start request message (INVITE) proceeds to step 433.

In step 433, the location information of the third terminating receiver 210 of the second location server 210 is provided. The incoming call processing server 205 receiving the location information of the third called terminal transmits a message (INVITE) requesting the start of a session for call establishment to the third incoming call processing server 211 (step 435). In response to the message INVITE, the third incoming call processing server 211 proceeds to step 437 and provides the session start request message INVITE to the third called terminal 213.

In addition, a call channel is opened between the calling terminal 201 and the third called terminal 213 by a SIP protocol message indicating a ring occurrence and a call call connection.

As described above, the SIP protocol-based non-answer call transfer method according to the present invention, by installing a separate application server performing a call transfer service according to the SIP protocol between the calling terminal, the incoming call processing server, and the application server When the called terminal is unresponsive for a predetermined time by exchanging a simple SIP message, the call environment is switched to a third preset called terminal, thereby further improving the network environment.

While the invention has been shown and described with respect to specific preferred embodiments thereof, the invention is not limited to the embodiments described above, and is commonly used in the art to which the invention pertains without departing from the spirit of the invention as claimed in the claims. Anyone with knowledge will be able to make various variations.

1 is a diagram showing the configuration of a call switching device when the non-response based on the SIP protocol to which the present invention is applied.

2 is a flowchart illustrating a call switching process when no response based on the SIP protocol according to the first embodiment of the present invention.

3 is a flowchart illustrating a call switching process when an unresponsive SIP protocol is based on a second embodiment of the present invention.

4 is a flowchart illustrating a call switching process when no response based on a SIP protocol according to a third embodiment of the present invention.

5 is a flowchart illustrating a call switching process when no response is based on the SIP protocol according to the fourth embodiment of the present invention.

<Explanation of symbols for main parts of drawing>

201: calling terminal 202: first location server

203: outgoing call processing server 205: incoming call processing server

207: terminating terminal 209: application server

210: second location server 211: third incoming call processing server

213: third destination terminal 251: gateway (MGCF)

253 public telephone network (PSTN / PLMN)

Claims (15)

After registering in the SIP network through the called terminal and activating the call transfer service when there is no response, after setting the third called terminal information, if there is no response from the called terminal for a predetermined time, the call is transferred to the third called terminal set by the called terminal. In the SIP protocol-based non-response call switching method, a) sending, by the calling terminal, a session start request message according to the SIP protocol to the calling call processing server and the called call processing server in order to make a call connection to the called terminal; b) After the step a) is executed, a service triggering procedure based on the service profile is performed through the incoming call processing server receiving the session start request message, and the session start request message to execute the service is transmitted to the application server. Sending a session start request message for a call connection to the called terminal; c) detecting, via the incoming call processing server, a SIP protocol message indicating that the ring is provided from the called terminal by step b) and transmitting the SIP protocol message to the application server and the calling terminal, respectively; d) starting a timer of an application server that has received a SIP protocol message indicating that it is ringing by step c); e) checking whether a response message for accepting a call connection has been received through the application server while the timer of step d) is running, and if not, sending a session start request message between the application server and the incoming call processing server; Terminating a session start request message for a call connection between the called terminal and the called call processing server through a cancellation and session start request message transmission ending procedure; f) through the originating call processing server, a SIP protocol message indicating that the session start request message for the call connection between the called terminal and the called call processing server is terminated and the call is output from the application server through step e); Transmitting to a terminal; And g) transmitting the session start request message from the incoming call processing server to the third called terminal through the third incoming call processing server according to the location information of the third called terminal provided through the second location server after executing step f). SIP protocol-based non-answering call switching method comprising the steps of connecting to the call. The transmission canceling procedure of the session start request message between the application server and the incoming call processing server of the step e), e-1) transmitting, by the incoming call processing server, a SIP protocol message (CANCEL) to stop transmitting the session start request message provided to the called terminal to the called call processing server; e-2) receiving a response message (200 OK) for receiving a SIP protocol message (CANCEL) provided from the incoming call processing server (205) of step e-1); e-3) SIP protocol message (CANCEL) to stop transmission of the session start request message provided from the incoming call processing server to the called terminal through the incoming call processing server receiving the SIP protocol message to cancel the transmission of the session start request message. Transmitting to the called terminal; And e-4) receiving the response message (200 OK) in response to the reception of the SIP protocol message (CANCEL) provided to the called terminal in e-2), and transmitting it to an application server, The session start request message transmission end procedure between the application server and the incoming call processing server may be performed by: e-5) A SIP protocol message (487 REQUEST TERMINATED) indicating that the request for the session start request message (INVITE) has been terminated by the SIP protocol message (CANCEL) received through step e-4) to the incoming call processing server. Transmitting; e-6) transmitting an acknowledgment message (ACK) to the called terminal to the SIP protocol message (487 REQUEST TERMINATED) provided from the incoming call processing server (205) through step e-5); e-7) transmitting to the application server that a SIP protocol message (487 REQUEST TERMINATED) received through step e-6) has been reached; And e-8) when the SIP protocol-based non-response comprises transmitting a response message (ACK) for the SIP protocol message (487 REQUEST TERMINATED) transmitted through the e-7) to the incoming call processing server. Call transfer method. The method of claim 1, wherein g), After the execution of step f), when the third destination terminal is to be routed through the circuit-switching network by analyzing the information of the third destination terminal through the incoming call processing server, the calling terminal and the public telephone network are connected by connecting a call channel through a gateway. SIP protocol-based non-answering call switching method characterized in that the call connection between the third destination terminal of the scheme. The SIP protocol according to claim 1, wherein the step f) comprises ending a session start request message for a call connection between the called terminal and the called call processing server through step e) to notify the address change output from the application server. Send the message to the calling terminal through the incoming call processing server and the outgoing call processing server, The step g), the step (f) is a SIP protocol characterized in that it is provided to send to the user whether to re-send the call in accordance with the information of the third destination terminal to be forwarded included in the SIP protocol message informing the address change Based call forwarding. The method of claim 4, wherein in the step g), when the third called terminal is a SIP UAL, it is provided to generate and transmit a session start request message confirming an address of the third called terminal from an originating terminal. SIP protocol-based non-response call transfer. The method of claim 4, wherein g) When the third destination terminal is a UAL of the public telephone network, the call switching method based on the SIP protocol based on the SIP protocol, characterized in that the circuit switching mobile telephone function of the calling terminal is automatically driven to establish a call to the third destination terminal. . The method of claim 4, wherein g) is When the third called terminal is an HTTP URL, the SIP protocol-based non-answer call switching method is provided to automatically set up a session requesting an incoming call to the third called terminal address by automatically driving the Internet browser of the calling terminal. . The method of claim 4, wherein g) is And when the third called terminal is an e-mail address, an e-mail program of the calling terminal is driven to connect with a call to the third called terminal. After registering in the SIP network through the called terminal and activating the call transfer service when there is no response, after setting the third called terminal information, if there is no response from the called terminal for a predetermined time, the call is transferred to the third called terminal set by the called terminal. In the SIP protocol-based non-response call switching method, h) sending, by the calling terminal, a session start request message according to the SIP protocol to the called terminal through the calling call processing server and the called call processing server in order to make a call connection to the called terminal; i) transmitting a SIP protocol message indicating that the ring is provided from the called terminal to the called call processing server and the calling terminal after executing step h); j) A service triggering procedure based on a service profile is performed through the incoming call processing server that receives the SIP protocol message indicating that the ring is in progress through step i), and a session start request message to execute the service is sent to the application server. Starting a timer after being sent; k) checking whether a response message for accepting a call connection is received from the called terminal while the timer is operated by step j), and canceling the transmission of the session start request message between the called call processing server and the called terminal if not received. Executing a session start request message transmission end procedure; l) after the execution of step k), after the session start request message for executing the call transfer service through the incoming call processing server is transmitted to the application server, the SIP protocol message indicating that the call is output from the application server is recalled. Transmitting to the calling terminal through an incoming call processing server and the outgoing call processing server, and transmitting a session start request message for call transfer to the incoming call processing server; And m) after the execution of step l), according to the location information of the third destination terminal provided through the second location server, a session start request message from the destination call processing server to the third destination terminal through the third destination call processing server; Call transfer method based on the SIP protocol, characterized in that consisting of the step of transmitting a call. The method of claim 9, wherein step l) After execution of step k), if the third destination terminal should be routed through the circuit-switching network by analyzing the information of the third destination terminal through the incoming call processing server, the call terminal and the public telephone network are connected by connecting a call channel through a gateway. SIP protocol-based non-answering call switching method characterized in that the call connection between the third destination terminal of the scheme. The SIP protocol of claim 9, wherein the step l) terminates the session start request message for the call connection between the called terminal and the called call processing server through step k) to notify the address change output from the application server. Send the message to the calling terminal through the incoming call processing server and the outgoing call processing server, The m) step, the call transfer method when no response based on the SIP protocol, characterized in that it is provided to redial the call according to the information of the third destination terminal to be forwarded included in the SIP protocol message informing the address change in step l) . 12. The method of claim 11, wherein in step m), when the third destination terminal is a SIP UAL, it is provided to generate and transmit a session start request message for confirming an address of the third destination terminal from an originating terminal. SIP protocol-based non-response call transfer method. The method of claim 11, wherein step m) When the third destination terminal is a UAL of the public telephone network, the call switching method based on the SIP protocol based on the SIP protocol, characterized in that the circuit switching mobile telephone function of the calling terminal is automatically driven to establish a call to the third destination terminal. . The method of claim 11, wherein m), In case the third called terminal is an HTTP URL, the SIP protocol-based non-response call switching is provided to automatically set up a session requesting an incoming call to the third called terminal address by automatically driving the Internet browser of the calling terminal. Way. The method of claim 11, wherein m), And when the third called terminal is an e-mail address, an e-mail program of the calling terminal is driven to connect to a call other than the third called terminal.