KR20100019265A - System and method for video telephony chatting in different networks - Google Patents

Abstract

The present invention relates to a video chat system and a method for interworking in a heterogeneous video communication network, and in order to perform a video chat between a 3G-324M terminal and a SIP terminal in which a session is established, when the 3G-324M terminal requests a video chat, the converter 3G. When the chat capability of the -324M terminal is stored and the chat capability of the 3G-324M terminal is requested from the SIP terminal, the chat capability of the stored 3G-324M terminal is transmitted to the SIP terminal, and the SIP terminal requests a video chat. The present invention provides a video chat system and method for interworking in a heterogeneous video communication network for transmitting a chat function to a 3G-324M terminal after receiving a request for transmission of a chat capability to a SIP terminal. According to the present invention, it is possible to quickly exchange the video chat capability between the SIP terminal and the 3G-324M terminal through the converter, it is possible to perform text-based message transfer between the SIP terminal and the 3G-324M terminal.

Description

System and method for video telephony chatting in different networks

The present invention relates to a video communication system and method, and more particularly, to a video chat system and method interworking in a heterogeneous video communication network that performs video chat by interworking video protocol terminals based on different protocols.

Wireless mobile communication technology has developed into GSM, GPRS, and WCDMA networks standardized at the 3rd Generation Partnership Projects (3GPP) International Standardization Conference, and IS-95A, IS95-B, CDMA 2000 1x and CDMA 1x-EVDO networks have been developed. Among these wireless mobile communication technologies, in the case of the IMT-2000 network, the synchronous IMT-2000 is called CDMA 2000 1x-EVDO, and the asynchronous IMT-2000 is called WCDMA.

Here, for video telephony service, WCDMA network is provided based on wired circuit network, and part of ITU-T H.324 protocol standard is changed to 3GPP standardization organization for wireless circuit network and standardized to 3G-324M protocol standard. On the other hand, in the CDMA 2000 1x-EVDO network, the ITU-T H.323 protocol standard used in the wired packet network is used for the wireless packet network without a separate standard in the wireless network.

On the other hand, SIP (Session Initiation Protocol) based provides a video call service that integrates a synchronous network and an asynchronous network. Web phones are in the spotlight as the next generation technology because they provide a video call service using an existing packet data network and are inexpensive and can create new services in combination with computer technology.

However, since video communication networks are implemented as different protocol based sub-networks by different operators, subscribers who subscribe to video call service provided based on one sub-network can try to make video calls to subscribers to other sub-networks. In this case, there has been a problem of implementing interworking between networks based on different protocols.

Therefore, recently, interworking technology has been developed between heterogeneous video communication networks which perform video calls between terminals belonging to heterogeneous video communication networks and perform video telephony chatting (VTC) for exchanging text-based messages during video calls.

Accordingly, a first object of the present invention is to provide an image chat system and method interoperating in a heterogeneous communication network that performs text-based message transfer between a SIP terminal and a 3G-324M terminal.

A second object of the present invention is to provide a video chat system and method interworking in a heterogeneous communication network capable of quickly exchanging video chat capability between a SIP terminal and a 3G-324M terminal.

In order to achieve the above object, the present invention provides a video chat system interoperating in a heterogeneous video communication network comprising a 3G-324M terminal, a SIP terminal and a converter. The 3G-324M terminal establishes a session based on the WCDMA network. The SIP terminal establishes a session based on the SIP network. The translator relays the connection between the 3G-324M terminal and the SIP terminal in which a session is established based on an IMS network. In particular, the converter comprises a receiver, a storage, a transmitter and a controller. The receiving unit receives an image chat request message requesting a video chat with the SIP terminal from the 3G-324M terminal. The storage unit stores the chat capability of the 3G-324M terminal included in the video chat request message. The transmitter converts the image chat request message into a first option message and transmits the image chat request message to the SIP terminal. When the control unit receives a second option message requesting the chatting capability of the 3G-324M terminal from the SIP terminal through the receiving unit, the controller transmits the chatting capability of the stored 3G-324M terminal as a second response message through the transmission unit. Send to the SIP terminal.

In addition, the converter may include a receiver, a transmitter, and a controller. The receiving unit receives a first option message for requesting a chatting capability of the 3G-324M terminal for video chatting with the 3G-324M terminal from the SIP terminal. The transmission unit transmits a second option message to the SIP terminal requesting transmission of the chat capability of the SIP terminal. The controller receives the chat capability of the SIP terminal through the receiver through a first response message to the second option message from the SIP terminal, and includes a chat capability of the SIP terminal. Send a message to the 3G-324M terminal.

Meanwhile, the present invention also provides a video chat method between a 3G-324M terminal and a SIP terminal in which a converter and a session are established. First, the converter receives an image chat request message requesting an image chat with the SIP terminal from the 3G-324M terminal. Next, the converter stores the chat capability of the 3G-324M terminal included in the video chat request message. Next, the converter converts the image chat request message into a first option message and transmits the message to the SIP terminal. The converter then receives a second option message from the SIP terminal requesting the chat capability of the 3G-324M terminal. And the converter transmits the chat capability of the stored 3G-324M terminal to the SIP terminal through a second response message.

Meanwhile, the present invention also provides a video chat method between a 3G-324M terminal and a SIP terminal in which a converter and a session are established. First, the converter receives a first option message requesting a chat capability of the 3G-324M terminal for video chatting with the 3G-324M terminal from the SIP terminal. Next, the converter transmits a second option message to the SIP terminal requesting transmission of the chat capability of the SIP terminal. The converter then receives the chat capability of the SIP terminal from the SIP terminal via a first response message to the second option message. The converter performs a process of transmitting an image chat request message of the SIP terminal including the chat capability of the SIP terminal to the 3G-324M terminal.

According to the present invention, it is possible to perform video chat for text-based message transmission between a heterogeneous communication network, for example, a SIP terminal based on a SIP network (wired internet network) and a 3G-324M terminal based on a WCDMA network (wireless internet network). It has the effect of making it work.

In addition, when the 3G-324M terminal requests a video chat, the converter stores the chat capability of the 3G-324M terminal and then sends the chat capability of the stored 3G-324M terminal to the SIP terminal when the 3G-324M terminal requests the transmission of the chat capability. When the SIP terminal requests a video chat, the converter requests and transmits a chat capability to the SIP terminal, and then sends a video chat request message to the 3G-324M terminal to the 3G-324M terminal. After exchanging the video chat capability between the terminal and the 3G-324M terminal quickly, there is an effect that the image chat can be performed through the exchange.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Video chat system

As shown in FIGS. 1 and 2, the video chat system 100 according to the present embodiment includes a 3G-324M terminal 10, a SIP terminal 70, a 3G-324M terminal 10, and a SIP terminal 70. It is configured to include a video communication network 20 for connecting.

Each of the 3G-324M terminal 10 and the SIP terminal 70 includes a communication unit, a camera module, a voice processing unit, and a display unit for performing a video call, and an input unit for user's key input and video chat, respectively. It has a microprocessor capable of controlling the element.

The video communication network 20 includes a WCDMA network 30, an SIP network 60, an IMS (IP Multimedia Subsystem) network 50 connecting the WCDMA network 30 and the SIP network 60.

The WCDMA network 30 is a mobile communication network (wireless internet network) based on 3G-324M, and provides a video communication service of the 3G-324M terminal 10. The WCDMA network 30 includes a home location register (HLR) 33, a mobile switching center 31 (Mobile Switching Center (MSC)), and a gateway switch 35 (Cellular Gateway Switch (CGS)). do. The home location register 33 uses the information of subscribers subscribed to the video communication service to database the routing information for the video call call connection between the called terminals. The gateway exchange 35 performs routing between networks by using routing information, and in particular, relays a signal between the mobile communication switching center 31 and the converter 50 of the IMS network 40.

The SIP network 60 is a wired communication network (wired internet network) based on SIP, and provides a video communication service of the SIP terminal 70. The SIP network 60 allows the SIP terminal 70 to be assigned a simple IP address or mobile IP address, access SIP based on the received IP address, and perform SIP registration, and SIP information registered by the SIP terminal 70. It includes a multimedia session control system (MSS) for storing the. The MSS 61 uses the subscriber information of the video call service implemented on the basis of SIP-based home and other sub-networks to database the routing information for the video call call connection between the originating and receiving terminals, and according to the routing information. Execute interworking between them. In addition, the SIP network 60 may further include an application server (AS; Application Server) belonging to the SIP server, the location server, the IMS network 40, a proxy server, a redirect server, and the like. have.

In addition, the IMS network 40 relays the connection between the heterogeneous WCDMA network 30 and the SIP network 60 to connect the 3G-324M terminal 10 and the SIP terminal 70 in which a session is established. The IMS network 40 is constructed based on SIP, and includes a converter 50 (Inter-working Media Gateway (IMG)) that performs protocol change between the WCDMA network 30 and the SIP network 60. The IMS network 40 may further include an MMS, an AS and a multimedia resource controller (MRC) belonging to the SIP network 60.

In particular, the converter 50 of the IMS network 40 includes a receiver 51, a storage 53, a transmitter 55, and a controller 57. The receiving unit 51 receives a message from the 3G-324M terminal 10 and the SIP terminal 70. The transmitter 53 transmits a message by converting each protocol into the 3G-324M terminal 10 and the SIP terminal 70. In addition, the control unit 57 performs the overall control operation of the converter 50, and controls the performance of the image chat between the 3G-324M terminal 10 and the SIP terminal 70. In particular, the controller 57 controls the exchange of chat capability for performing video chat between the 3G-324M terminal 10 and the SIP terminal 70.

Here, the chat capability is expressed as Session Description Protocol (SDP), and includes the number of supported versions and supported versions. For example, the chat capability may be expressed in the form of [number of supported versions] [_] [supported versions]. Where [number of supported versions] specifies the number of chat capabilities that he supports, up to five can be specified. [Supported version] is set as the number of supported versions, and [_] is used to distinguish between each version.

Meanwhile, in the present embodiment, the SDP discloses an example of only chatting ability, but may also be set by expressing voice or video capability.

In particular, the converter 50 performs a chat capability exchange in a different manner depending on which of the 3G-324M terminal 10 and the SIP terminal 70 in which the session is established first request a video chat. At this time, the message exchange between the converter 50 and the 3G-324M terminal 10 is performed by the video chat request message (VTC) and the video chat acceptance message (VTC_ACK), and each message is a chat capability of one or the other terminal. It includes. The exchange of the option message between the converter 50 and the SIP terminal 70 is performed by OPTIONS, and the exchange of the response message is performed with 200 OK.

When the 3G-324M terminal 10 requests a video chat, the converter 50 performs a chat capability exchange as follows.

The receiver 51 includes a video chat request message (VTC) for requesting a video chat with the SIP terminal 70 from the 3G-324M terminal 10. At this time, the video chat request message (VTC) includes the chat capability of the 3G-324M terminal (10).

The storage unit 53 extracts and stores the chat capability of the 3G-324M terminal 10 included in the received video chat request message VTC under the control of the controller 57.

The transmission unit 55 converts the received image chat request message VTC into a first option message OPTIONS and transmits the converted video chat request message VTC to the SIP terminal 70. In this case, the first option message OPTIONS does not include the chat capability of the 3G-324M terminal 10.

When the control unit 57 receives the second option message OPTIONS requesting the chat capability of the 3G-324M terminal 10 from the SIP terminal 70 through the receiving unit 51, the stored 3G-324M terminal 10 is stored. The chat capability of the second response message (200 OK) is transmitted to the SIP terminal 70 through the transmission unit 55.

In addition, when the control unit 57 receives the first response message 200 OK including the chatting capability of the SIP terminal 70 to the first option message OPTIONS through the receiving unit 51 from the SIP terminal 70, The video chat acceptance message (VTC_ACK) including the chat capability of the SIP terminal 70 is transmitted to the 3G-324M terminal 10 through the transmitter 55. In this case, one supported version is displayed in the image chat acceptance message (VTC_ACK). The SIP terminal 70 transmits a video chat acceptance message (VTC_ACK) to the 3G-324M terminal 10 as the latest version of the supported version of the chat capability of the received 3G-324M terminal 10.

As described above, the 3G-324M terminal 10 and the SIP terminal 70 confirm the chat capability of the counterpart, respectively, and perform a video chat through the converter 50.

Next, when requesting a video chat from the SIP terminal 70, the converter 50 performs a chat capability exchange as follows.

The receiving unit 51 first receives a first option message OPTIONS requesting a chat capability of the 3G-324M terminal 10 for video chatting with the 3G-324M terminal 10 from the SIP terminal 70.

The control unit 57 transmits the second option message OPTIONS for requesting the chat capability of the SIP terminal 70 required for the preparation of the video chat request message VTC to be transmitted to the 3G-324M terminal 10. It transmits to the SIP terminal 70 through. The controller 57 receives the chat capability of the SIP terminal 70 from the SIP terminal 70 through the first response message 200 OK to the receiver 51.

The controller 57 transmits the video chat request message VTC requested by the SIP terminal 70 including the chat capability of the SIP terminal 70 to the 3G-324M terminal 10.

When the control unit 57 receives the video chat acceptance message (VTC_ACK) including the chat capability of the 3G-324M terminal 10 from the 3G-324M terminal 10 through the receiving unit 51, the 3G-324M terminal 10 ) Chat capability of the second transmission to the SIP terminal 70 through the transmission unit 55 in a second response message (200 OK). In this case, one supported version is displayed in the image chat acceptance message (VTC_ACK). The 3G-324M terminal 10 transmits the video chat acceptance message VTC_ACK to the SIP terminal 70 through the converter 50 as the latest version of the supported version of the chat capability of the received SIP terminal 70.

As described above, the 3G-324M terminal 10 and the SIP terminal 70 respectively check the chat capability of the other party, and then perform a video chat through the converter 50.

Video chat method

An image chat method in the image chat system 100 according to the present embodiment will be described with reference to FIGS. 3 and 4 as follows. 3 is a first flowchart illustrating a video chat method when the 3G-324M terminal 10 requests a video chat during a video call between the 3G-324M terminal 10 and the SIP terminal 70. FIG. 4 is a second flowchart illustrating a video chat method when the SIP terminal 70 requests a video chat during a video call between the 3G-324M terminal 10 and the SIP terminal 70.

Referring to FIG. 3, a video chat method in the case where a 3G-324M terminal 10 requests a video chat is as follows.

First, a session is established between the 3G-324M terminal 10 and the converter 50 in step S101, and after a session is established between the SIP terminal 70 and the converter 50 in step S103, the 3G-324M terminal ( If the user of 10) requests a video chat with the user of the SIP terminal 70, the converter 50 requests the video chat with the SIP terminal 70 from the 3G-324M terminal 10 in step S105. Receive a request message (VTC). In this case, the user of the 3G-324M terminal 10 may request an image chat through key selection of the input unit.

Next, in step S107, the converter 50 stores the chat capability of the 3G-324M terminal 10 included in the received video chat request message VTC, and removes the video chat request message VTC received in step S109. 1 is converted into an option message (OPTIONS) and transmitted to the SIP terminal 70. At this time, the first option message (OPTIONS) is a message requesting the transmission of the chat capability of the SIP terminal 70, and does not include the chat capability of the 3G-324M terminal 10.

Next, in step S111, the converter 50 receives the first response message 200 OK corresponding to the first option message OPTIONS from the SIP terminal 70. The first response message 200 OK includes the chat capability of the SIP terminal 70. That is, when the user of the SIP terminal 70 accepts the video chat request of the 3G-324M terminal 10 through key selection, the SIP terminal 70 transmits the first response message 200 OK to the converter 50. do.

Next, in step S113, the converter 50 transmits an image chat acceptance message (VTC_ACK) to the 3G-324M terminal 10. The video chat acceptance message (VTC_ACK) includes the chat capability of the SIP terminal 70. The 3G-324M terminal 10 displays the video chat acceptance message (VTC_ACK) on the screen for the user to confirm.

Next, the converter 50 receives a second option message OPTIONS requesting transmission of the chat capability of the 3G-324M terminal 10 from the SIP terminal 70 in step S115.

Next, in step S117, the converter 50 transmits the chat capability of the stored 3G-324M terminal 10 to the SIP terminal 70 as a second response message 200 OK. That is, the converter 50 does not transmit the second option message OPTIONS to the 3G-324M terminal 10, but directly transmits the second response message OPTIONS to the SIP terminal 70, thereby allowing the SIP terminal ( 70) and the video chat capability between the 3G-324M terminal 10 can be quickly exchanged.

As described above, after the 3G-324M terminal 10 and the SIP terminal 70 confirm the chat capability of the counterpart, the converter 50 performs a video chat between the 3G-324M terminal 10 and the SIP terminal 70 in step S119. Relay to perform.

Referring to FIG. 4, the video chat method in the case where the SIP terminal 70 requests a video chat is as follows.

First, a session is established between the 3G-324M terminal 10 and the converter 50 in step S201, and after a session is established between the SIP terminal 70 and the converter 50 in step S103, the SIP terminal 70 is established. When the user of the 3G-324M terminal 10 requests a video chat with the user of the user, in step S205, the converter 50 requests a video chat with the 3G-324M terminal 10 from the SIP terminal 70. Receive OPTIONS.

In this case, the user of the SIP terminal 70 may request an image chat through key selection of the input unit. The SIP terminal 70 requests the chat capability of the 3G-324M terminal 10 through the first option message (OPTIONS). However, the first option message OPTIONS does not include the chat capability of the SIP terminal 70.

Next, in step S207, the converter 50 transmits the second option message OPTIONS to the SIP terminal 70 to request transmission of the chat capability of the SIP terminal 70. That is, the converter 50 receives the video chat request of the SIP terminal 70 through the first option message OPTIONS, but the SIP required for the creation of the video chat request message VTC to be transmitted to the 3G-324M terminal 10. There is no chat capability information of the terminal 70. Therefore, the converter 50 directly transmits the second option message OPTIONS requesting the transmission of the chat capability of the SIP terminal 70 to the SIP terminal 70.

Next, the converter 50 receives the first response message 200 OK including the chat capability of the SIP terminal 70 from the SIP terminal 70 in step S209. Subsequently, in step S211, the converter 50 transmits a video chat request message (VTC) including the chat capability of the SIP terminal 70 to the 3G-324M terminal 10.

Next, in step S213, the converter 50 receives the image chat acceptance message VTC_ACR from the 3G-324M terminal 10. That is, when the user of the 3G-324M terminal 10 accepts the video chat request of the SIP terminal 70 through key selection, the 3G-324M terminal 10 sends a video chat acceptance message (VTC_ACK) to the converter 50. send. At this time, the video chat acceptance message (VTC_ACK) includes the chat capability of the 3G-324M terminal 10.

Next, in step S215, the converter 50 transmits the chat capability of the received 3G-324M terminal 10 to the SIP terminal 70 as a second response message 200 OK. In this case, the second response message 200 OK is a response message to the first option message OPTIONS.

As described above, after the 3G-324M terminal 10 and the SIP terminal 70 confirm the chat capability of the counterpart, the converter 50 performs a video chat between the 3G-324M terminal 10 and the SIP terminal 70 in step S217. Relay to perform.

On the other hand, the embodiments disclosed in the specification and drawings are merely presented specific examples to aid understanding, and are not intended to limit the scope of the present invention. It is apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

The present invention relates to a heterogeneous video communication network in which a user of a SIP terminal and a 3G-324M terminal using a heterogeneous video communication network, a SIP network, and a WCDMA network, respectively, can exchange messages based on a user's request during a video call. Provided are an image chat system and method. According to the present invention, it is possible to perform video chatting after quickly exchanging video chatting capability between a SIP terminal and a 3G-324M terminal through a converter, so that even a user who uses a SIP network and a WCDMA network may perform video chatting smoothly. Can be done.

1 is a schematic diagram showing an image chat system interworking in a heterogeneous video communication network according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of the converter of FIG. 1.

3 is a first flowchart illustrating an image chat method interworking in a heterogeneous video communication network according to an exemplary embodiment of the present invention.

4 is a second flowchart illustrating an image chat method interworking in a heterogeneous video communication network according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

10: 3G-324M terminal 20: video communication network

30: WCDMA network 40: IMS network

50: converter 60: SIP network

70: SIP terminal 100: video chat system

Claims (10)

A 3G-324M terminal establishing a session based on the WCDMA network; A SIP terminal for establishing a session based on the SIP network; And a converter for relaying a connection between the 3G-324M terminal and the SIP terminal, on which a session is established based on an IMS network. The converter, A receiving unit for receiving an image chat request message requesting an image chat with the SIP terminal from the 3G-324M terminal; A storage unit for storing a chat capability of the 3G-324M terminal included in the video chat request message; A transmission unit converting the image chat request message into a first option message and transmitting the first chat message to the SIP terminal; When the second option message requesting the chat capability of the 3G-324M terminal is received from the SIP terminal through the receiver, the chat capability of the stored 3G-324M terminal is transmitted to the SIP terminal through the transmission unit as a second response message. And a control unit for transmitting the video chatting system interworking in a heterogeneous video communication network. The method of claim 1, wherein the control unit, When the first response message including the chat capability of the SIP terminal with respect to the first option message is received from the SIP terminal through the receiver, an image chat acceptance message including the chat capability of the SIP terminal is transmitted through the transmitter. An image chat system interworking in a heterogeneous video communication network, characterized in that the transmission to the 3G-324M terminal. A 3G-324M terminal establishing a session based on the WCDMA network; A SIP terminal for establishing a session based on the SIP network; And a converter for relaying a connection between the 3G-324M terminal and the SIP terminal, on which a session is established based on an IMS network. The converter, A receiving unit for receiving a first option message requesting a chat capability of the 3G-324M terminal from the SIP terminal for video chatting with the 3G-324M terminal; A transmission unit for transmitting a second option message for requesting transmission of chat capability of the SIP terminal to the SIP terminal; When receiving the chat capability of the SIP terminal through the first response message to the second option message from the SIP terminal through the receiving unit, the video chat request message of the SIP terminal including the chat capability of the SIP terminal; Control unit for transmitting to the 3G-324M terminal; Video chat system interlocked in a heterogeneous video communication network comprising a. The method of claim 3, wherein the control unit, Upon receiving the video chat acceptance message including the chat capability of the 3G-324M terminal from the 3G-324M terminal through the receiving unit, the chat capability of the 3G-324M terminal as the second response message to the first option message. An image chat system interworking in a heterogeneous video communication network, characterized in that for transmitting to the SIP terminal through the transmission unit. The method according to any one of claims 1 to 4, The chat capability is expressed in SDP (Session Description Protocol), the video chat system interworking in heterogeneous video communication network, characterized in that it comprises a number of supported versions and supported versions. The method of claim 5, The video chat acceptance message interworked in a heterogeneous video communication network, characterized in that the transmission of the latest version of the supported version of the chat capability received. As a video chat method between the 3G-324M terminal and the SIP terminal in which a converter and a session are established, Receiving, by the converter, an image chat request message requesting a video chat with the SIP terminal from the 3G-324M terminal; The converter is configured to store a chat capability of the 3G-324M terminal included in the video chat request message; Converting the video chat request message into a first option message and transmitting the first chat message to the SIP terminal; Receiving, by the converter, a second option message requesting a chatting capability of the 3G-324M terminal from the SIP terminal; And the converter transmits the chat capability of the stored 3G-324M terminal to the SIP terminal through a second response message. 8. The method of claim 7, wherein the storage is performed between the storing process and the receiving process. The converter receiving a first response message from the SIP terminal, the first response message including a chat capability of the SIP terminal with respect to the first option message; The converter further comprises the step of transmitting the video chat acceptance message including the chat capability of the SIP terminal to the 3G-324M terminal; video chat method interworking in heterogeneous video communication network, characterized in that it further comprises. As a video chat method between 3G-324M terminal and SIP terminal that has established a session with a converter, Receiving, by the converter, a first option message requesting a chatting capability of the 3G-324M terminal for video chatting with the 3G-324M terminal from the SIP terminal; The converter transmitting a second option message to the SIP terminal requesting transmission of the chat capability of the SIP terminal; Receiving, by the converter, a chat capability of the SIP terminal from the SIP terminal through a first response message to the second option message; The converter comprises the step of transmitting a video chat request message of the SIP terminal including the chat capability of the SIP terminal to the 3G-324M terminal; video chat interworking in heterogeneous video communication network comprising a. The method of claim 9, wherein the image chat request message is performed after the process of transmitting the video chat request message to the 3G-324M terminal. The converter receiving from the 3G-324M terminal an image chat acceptance message including the chat capability of the 3G-324M terminal; The converter further comprises the step of transmitting the chat capability of the 3G-324M terminal to the SIP terminal via a second response message to the first option message; Video chat method interworking in a heterogeneous video communication network further comprising. .

Images