Method and system for group call using unicast and multicast

A method and a system for performing a group call using unicast and multicast are provided. A group call method performed by a first client device, may include: establishing a media session with a server providing a group call service based on a group call request from the first client device; transmitting, to the server through the media session, at least one first packet including a first source identifier of the first client device; providing a user interface at the first client device, that enables selecting at least one second client device from a plurality of second client devices that participate in a group call initiated by the first client device; and transmitting, from the first client device to the server, at least one second packet including a second source identifier of the selected at least one second client device as a destination of data included in the at least one second packet.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Korean Patent Application No. 10-2019-0099571, filed Aug. 14, 2019 in the Korean Intellectual Property Office (KIPO), the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

Apparatuses and methods consistent with example embodiments relate to providing a group call using unicast and multicast.

2. Description of Related Art

A conference call refers to a group call that allows a plurality of users to talk at the same time. For example, a group call service may be provided by a group telephone server that is configured to transfer audio data and media (e.g. as video) between group call participants. However, data transferred through the group call is transmitted to each of the group call participants in a corresponding instance of the group call. For example, in an instance of a group call participated in by five users including user 1, user 2, user 3, user 4, and user 5, data of audio/video of the user 1 is also transferred to each of the remaining users, that is, the user 2, the user 3, the user 4, and the user 5. That is, in the group call according to the related art, data is broadcasted at all times.

SUMMARY

Example embodiments provide a group call method and system that may transmit data in a form of unicast or multicast to selected participants among a plurality of participants in an instance of a group call during the progress of the corresponding instance.

According to an aspect of an example embodiment, there is provided a group call method performed by a first client device, the group call method including: establishing a media session with a server providing a group call service based on a group call request from the first client device; transmitting, to the server through the media session, at least one first packet including a first source identifier of the first client device; providing a user interface at the first client device, that enables selecting at least one second client device from a plurality of second client devices that participate in a group call initiated by the first client device; and transmitting, from the first client device to the server, at least one second packet including a second source identifier of the selected at least one second client device as a destination of data included in the at least one second packet.

The transmitting the at least one first packet may include transmitting the at least one first packet to each of the plurality of second client devices in a form of broadcast through the server. The transmitting the at least one second packet may include transmitting the at least one second packet to the selected at least one second client device in a form of unicast or multicast through the server.

The group call method may further include: generating the at least one second packet according to an extended transfer protocol of a real-time transport protocol (RTP) to include a field for recording at least one destination synchronization source (dSSRC) corresponding to the destination of the data included in the at least one second packet.

The at least one second packet generated according to the extended transfer protocol of the RTP may further include a field for counting a number of dSSRCs.

The group call method may further include: receiving, from the server, the second source identifier of the selected at least one second client device through the user interface; and adding the received second source identifier to the at least one second packet.

According to an aspect of another example embodiment, there is provided a group call method performed by a server, the method including: establishing a media session with a first client device based on a group call request from the first client device, to initiate a group call; receiving, from the first client device through the media session, at least one first packet including a first source identifier of the first client device; broadcasting the at least one first packet to each of a plurality of second client devices participating in the group call; receiving, from the first client device through the media session, at least one second packet including a second source identifier of at least one second client device selected from the plurality of second client device, as a destination of data included in the at least one second packet; and transferring data included in the at least one second packet to the at least one selected second client device in a form of unicast or multicast, based on the second identifier of the at least one selected second client device.

The at least one second packet may be generated at the first client device to include the second source identifier of the selected at least one second client device.

The at least one second packet may be generated at the first client device according to an extended transfer protocol of a real-time transport protocol (RTP) and transmitted. The at least one second packet generated according to the extended transfer protocol of the RTP may include a field for recording at least one destination synchronization source (dSSRC) corresponding to the destination of data included in the at least one second packet.

The at least one second packet transmitted according to the extended transfer protocol of the RTP may further include a field for counting a number of dSSRCs.

The group call method may further include: transmitting, to the first client device, the second source identifier of the selected at least one second client device in response to a request from the first client device for transmitting the data to the selected at least one second client device.

According to an aspect of another example embodiment, there is provided a non-transitory computer-readable record medium storing instructions that, when executed by a processor, cause the processor to perform the group call method.

According to an aspect of another example embodiment, there is provided a computer apparatus including: at least one memory configured to store computer-readable instructions; and at least one processor configured to execute the computer-readable instructions to: establish a media session among a first client device, a server providing a group call service, and a plurality of second client devices, based on a group call request from the first client device; receive, from the first client device through the media session, at least one first packet including a first source identifier of the first client device; broadcast the at least one first packet to each of the plurality of second client devices participating in a group call initiated by the first client device; receive, from the first client device through the media session, at least one second packet including, as a destination of data included in the at least one first packet, a second source identifier of at least one second client device selected from the plurality of second client devices; and transfer data included in the at least one second packet to the at least one selected second client device in a form of unicast or multicast, based on the second source identifier of the at least one selected second client device.

The at least one processor may be further configured to execute the computer-readable instructions to: identify the destination of the data included in the at least one second packet based on a type of the data and a user identifier included in the at least one second packet.

The at least one processor may be further configured to execute the computer-readable instructions to: identify an internet protocol address and a connection port of the at least one selected second client device, as the destination of the data included in the at least one second packet.

The type of the data may be a video data type or an audio data type. The at least one processor may be further configured to execute the computer-readable instructions to: identify an internet protocol address and a connection port of the at least one selected second client device, as the destination of the data included in the at least one second packet, based on whether the type of the data is the video data type or the audio data type.

The at least one processor may be further configured to execute the computer-readable instructions to: identify the destination of the data included in the at least one second packet based on the second source identifier included in the at least one second packet, and a look-up table indicating the destination associated with the second source identifier.

DETAILED DESCRIPTION

Software and/or data may be embodied permanently or temporarily in any type of machine, component, physical or virtual equipment, or computer record medium or device, capable of providing instructions or data to, or being interpreted by, a hardware device. The software also may be distributed over network coupled computer systems so that the software is stored and executed in a distributed fashion. In particular, for example, software and data may be stored by one or more computer readable record mediums, including the tangible or non-transitory computer-readable storage media discussed herein.

Hereinafter, example embodiments are described with reference to the accompanying drawings.

A group call system according to example embodiments may be implemented by at least one computer system, and a group call method according to example embodiments may be performed through at least one computer apparatus included in the group call system. Here, a computer program according to example embodiments may be installed and executed on the computer apparatus, and the computer apparatus may perform the group call method under control of the executed computer program. The computer program may be stored in a computer-readable storage medium to execute the group call method on a computer in conjunction with the computer apparatus.

FIG. 1illustrates an example of a network environment according to at least one example embodiment. Referring toFIG. 1, the network environment may include a plurality of electronic devices110,120,130, and140, a plurality of servers150and160, and a network170.FIG. 1is provided as an example only. A number of electronic devices or a number of servers is not limited thereto. Also, the network environment ofFIG. 1is provided to describe one example among environments applicable to the example embodiments. An environment applicable to the example embodiments is not limited to the network environment ofFIG. 1.

Each of the plurality of electronic devices110,120,130, and140may be a stationary terminal or a mobile terminal that is configured as a computer apparatus. For example, the plurality of electronic devices110,120,130, and140may be a smartphone, a mobile phone, a navigation device, a computer, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a tablet PC, and the like. For example, althoughFIG. 1illustrates a shape of a smartphone as an example of the electronic device110, the electronic device110used herein may refer to one of various types of physical computer apparatuses capable of communicating with other electronic devices120,130, and140, and/or the servers150and160over the network170in a wireless or wired communication manner.

The communication scheme is not limited and may include a near field wireless communication scheme between devices as well as a communication scheme using a communication network (e.g., a mobile communication network, wired Internet, wireless Internet, and a broadcasting network) includable in the network170. For example, the network170may include at least one of network topologies that include a personal area network (PAN), a local area network (LAN), a campus area network (CAN), a metropolitan area network (MAN), a wide area network (WAN), a broadband network (BBN), and Internet. Also, the network170may include at least one of network topologies that include a bus network, a star network, a ring network, a mesh network, a star-bus network, a tree or hierarchical network, and the like. However, they are provided as examples only.

Each of the servers150and160may be configured as a computer apparatus or a plurality of computer apparatuses that provides an instruction, a code, a file, content, a service, and the like through communication with the plurality of electronic devices110,120,130, and140over the network170. For example, the server150may be a system that provides a service (e.g., a group call service or an audio conferencing service, a messaging service, a mail service, a social network service, a map service, a translation service, a financial service, a payment service, a search service, and a content providing service) to the plurality of electronic devices110,120,130, and140connected over the network170.

FIG. 2is a block diagram illustrating an example of a computer apparatus according to at least one example embodiment. For example, each of the plurality of electronic devices110,120,130, and140or each of the plurality of servers150and160may be implemented using a computer apparatus200ofFIG. 2.

Referring toFIG. 2, the computer apparatus200may include a memory210, a processor220, a communication interface230, and an input/output (I/O) interface240. The memory210may include a permanent mass storage device, such as random access (RAM), read only memory (ROM), and a disc drive, as a non-transitory computer-readable storage medium. Here, the permanent mass storage device, such as ROM and disc drive, may be included in the computer apparatus200as a separate permanent storage device different from the memory210. Also, an operating system (OS) and at least one program code may be stored in the memory210. Such software components may be loaded from another non-transitory computer-readable storage medium to the memory210. The other non-transitory computer-readable storage medium may include a non-transitory computer-readable storage medium, for example, a floppy drive, a disk, a tape, a DVD/CD-ROM drive, a memory card, etc. According to other example embodiments, software components may be loaded to the memory210through the communication interface230, instead of, or in addition to, the non-transitory computer-readable storage medium. For example, the software components may be loaded to the memory210of the computer apparatus200based on a computer program installed by files received over the network170.

The processor220may be configured to process computer-readable instructions of a computer program by performing basic arithmetic operations, logic operations, and I/O operations. The computer-readable instructions may be provided from the memory210or the communication interface230to the processor220. For example, the processor220may be configured to execute received instructions in response to a program code stored in a storage device, such as the memory220.

The communication interface230may provide a function for communication between the computer apparatus200and another apparatus, for example, the aforementioned storage devices, over the network170. For example, the processor220of the computer apparatus200may transfer data, a file, a request or an instruction created based on the program code stored in the storage device, such as the memory220, to other apparatuses over the network170under control of the communication interface230. The computer apparatus200may receive a signal, an instruction, data, a file, a command, and the like from another apparatus through the communication interface230of the computer apparatus200. For example, a signal, an instruction, data, a command, and the like received through the communication interface230may be transferred to the processor220or the memory210, and content, a file, and the like may be stored in a storage medium, for example, the permanent storage device, further includable in the computer apparatus200.

The I/O interface240may be a device used for interface with an I/O apparatus250. For example, an input device may include a device, such as a microphone, a keyboard, and a mouse, and an output device may include a device, such as a display device and a speaker. As another example, the I/O interface240may be a device for interface with an apparatus in which an input function and an output function are integrated into a single function, such as a touchscreen. The I/O apparatus250may be configured as a single apparatus with the computer apparatus200.

According to other example embodiments, the computer apparatus200may include a number of components greater than or less than a number of components shown inFIG. 2. For example, the computer apparatus200may include at least a portion of the I/O apparatus250, or may further include other components, for example, a transceiver, a database (DB), and the like.

FIG. 3illustrates an example of a group call system according to at least one example embodiment. The group call system according to the example embodiment may include a server310configured to provide a group call service and client devices320for a plurality of participants. Here, unlike the existing art, communication between the server310and the client devices320may be performed through an extended transfer protocol capable of including destination information in a packet according to example embodiments. For example, a case in which a first client device321, a second client device322, and a third client device323among the client devices320participate in a single group call instance may be considered. In this case, each of the first client device321, the second client device322, and the third client device323that participate in the corresponding group call instance may designate a specific participant and may transmit a packet. For example, the first client device321may designate the third client device323and may transfer media data, such as audio or video, to the designated third client323.

That is, according to the example embodiment, a participant of a group call service may transmit data to all of participants of a corresponding group call instance and may also transmit data to a specific participant or a small group of specific participants.

FIGS. 4 to 6illustrate examples of a group call process according to at least one example embodiment.

FIG. 4illustrates an example in which a first user410, a second user420, and a third user430participate in a group call instance. Here, each of the first user410, the second user420, and the third user430may correspond to one of the client devices320ofFIG. 3. Here, the server310may manage a table that includes source identifier (Srcid) and connecting information for each of the first user410, the second user420, and the third user430as shown in a table440. The table400may be stored in the server310, a client device of the first user410, or a memory provided separated from the server and the client device of the first user410. The source identifier (Srcid) refers to a unique value for each group call and, generally, may be used to identify a user who transmits data to the server310, as a source of the data received at the server310. The source identifier may also indicate a type of the source (e.g., an audio data source, a video data source, a still image data source, a text data source), along with the user who transmits the data (e.g., user A or user B). In addition, according to some example embodiment, the source identifier may be used to identify, as a source of data, one of the client devices320which transmits the data to the server310in association with connecting information, that is, to identify destination information of the data. Although not illustrated, the source identifier (Srcid) and the connecting information may be managed as a single table with other information about the first user410, the second user420, and the third user430. The connecting information may include an Internet protocol (IP) address and a connection port of the client devices of the first user410, the second user420, and the third user430. In response to receiving, from a client device of each user, a request for initiating or participating in a group call with call related information, such as a type of media to be transmitted or received, the server310may manage a table, such as the table440, by allocating at least one source identifier based on call related information received from the client device. The server310may transmit, to the client device initiating or participating in the group call, the source identifier allocated to the corresponding client device. Also, if other users are participating in the group call, the server310may transmit source identifiers of at least a portion of the other users participating in the group call to the client device of the user participating in the group call. Also, the server310may transmit source identifiers of at least a portion of other users participating in the group call to the client device of the user participating in the group call in response to a request from the client device or based on determination of the server310, during the group call. For example, it is assumed that, during a group call between the first user410and the second user420using all of video and audio, the third user430participates in the group call between the first user410and the second user420using the third client device323equipped with only an audio device. In response to the server310receiving a request from the third user430for participating in the group call with call related information of the third user430, the server310may allocate a source identifier Src5 to the third user430and may store the source identifier Src5 in the table in association with connecting information ip3/port1 corresponding to the source identifier Src5. Here, the server310may transmit, to the third client device323of the third user430, source identifier information of the first user410and the second user420already participating in the group call with the source identifier Src5 allocated to the third user430. Also, the server310may notify the first user410and the second user420already participating in the group call that the source identifier of the third user430is Src5.

Here, referring toFIG. 4, it is assumed that, when the first user1410, the second user420, and the third user430are participating in the group call, the first user410transmits a packet P1 and a packet P2 to the server310without designating at least a portion of users. Here, each of the packets P1 and P2 may include a source identifier. For example, when the packet P1 includes audio data and the packet P2 includes video data, the packet P1 may include a source identifier Src1 of the first user410for audio and the packet P2 may include a source identifier Src2 of the first user410for video. In this case, the server310may be aware that the packet P1 includes audio data from the source identifier Src1 included in the packet P1, and may transfer the packet P1 to user devices of the second user420and the third user430having audio sources through ip2/port1 and ip3/port1 by referring to the table440. Also, the server310may be aware that the packet P2 includes video data from the source identifier Src2 included in the packet P2, and may transfer the packet P2 to the user device of the second user420having the video source through ip2/port2 by referring to the table440. Here, since a video source is not allocated to the third user430, the packet P2 is not transferred to the third user430.

FIG. 5illustrates an example of a process in which the first user410transfers audio and video of the first user410only to the second user420during a group call. In response to receiving a request from the first user410for transferring audio and video only to the second user420during the group call, the server310may include destination information in a packet transmitted from the first user410and transfer the packet, which differs from an example in which a destination is not specified. During the group call, the server310may receive a packet P3 including audio and a packet P4 including video data, and may also receive a request for transferring the audio and video only to the second user420. The request for transferring the audio and video only to the second user420may be included in each of the packet P3 and the packet P4, or may be transmitted from the first user410to the server310separately from the packet P3 and the packet P4. The packet P3 and the packet P4 may include a source identifier Src3 and a source identifier Src4, respectively, and in response thereto, the server310may identify the source identifier Src3 as a destination of the packet P3 that includes the audio of the first user410, and may identify the source identifier Src4 as a destination of the a packet P4 that includes the video of the first user410, based on a table510ofFIG. 5. The table510may be stored in a client device of the first user410, the server310, or a memory that is separately provided from the client device of the first user410and the server310. In another example, the packets P3 and P4 transmitted from the client device of the first user410may include a user identifier of the second user420, in addition to the audio and the video respectively included in the packets P3 and P4, but may not include the source identifier Src3 and the source identifier Src4. Upon receipt of the packet P3, the server310may determine the source identifier Src3 as a destination of the packet P3 (or as a destination of data included in the packet P3 received from the first user410) based on the user identifier (e.g., “User 2”) of the second user420and the type of the data (i.e., audio type) included in the packet 3, with reference to the table440and/or table510. Also, upon receipt of the packet P4, the server310may determine the source identifier Src4 as a destination of the packet P4 (or as a destination of data included in the packet P4 received from the first user410) based on the user identifier (e.g., “User 2”) of the second user420and the type of the data (i.e., video type) included in the packet 4, with reference to the table440and/or table510.

The server310may transfer the packet P3 to ip2/port1 of the second user420corresponding to the source identifier Src3 designated in the packet P3 and may transfer the packet P4 to ip2/port2 of the second user420corresponding to the source identifier Src4 designated in the packet P4, by referring to the table440ofFIG. 4. Such a source identifier may be designated in a packet from the first user410until the request for transferring audio or video of the first user410only to the second user420during the group call is released from the first user410.

FIG. 6illustrates an example of a process in which the first user410transfers only video of the first user410to the second user420and transfers only audio of the first user410to the third user430during a group call. In response to receiving a request from the first user410for transferring video of the first user410only to the second user420and audio of the first user410only to the third user430, the server310may include destination information in a packet transmitted from the first user410and transfer the packet, which differs from an example in which a destination is not specified. During the group call, the request for transferring video of the first user410only to the second user420and audio of the first user410only to the third user430may be received from the first user410. In response thereto, a source identifier Src4 may be designated as a destination of a packet P5 for the video of the first user410and a source identifier Src5 may be designated as a destination of a packet P6 for the audio of the first user410, based on source identifiers of other users obtained, for example, by referring to a table610ofFIG. 6. In this case, the server310may transfer the packet P5 to ip2/port2 of the second user420corresponding to the source identifier Src4 designated in the packet P5 and may transfer the packet P6 to ip3/port1 of the third user430corresponding to the source identifier Src5 designated in the packet P6, by referring to the table440ofFIG. 4.

As described above, an existing transfer protocol may be extended to designate destination information. Such existing transfer protocols transfer a packet to all of participants in a form of broadcast and thus, do not need to designate a destination. Accordingly, there is no field to include destination information. The example embodiment may extend the existing transfer protocol by adding a field for designating destination information using a reserved area in a header of a packet according to the existing transfer protocol.

Also, at least two users may be designated for a single packet. InFIG. 7, a case in which a fourth user710and a fifth user720as well as the first user410, the second user420, and the third user430further participate in a group call instance is considered.FIG. 7illustrates an example in which the first user410designates the second user420and the fifth user720and transfers audio data. In response to receiving a request from the first user410for transferring audio only to the second user420and the fifth user720, the server310may include destination information in a packet transmitted from the first user410and may transfer the packet, which differs from an example in which a destination is not specified. During the group call, a request for transferring audio only to the second user420and the fifth user720may be received from the first user410. In response thereto, source identifiers Src3 and Src8 may be designated as destination information in a packet P7 that includes audio of the first user410, based on source identifiers of other users received from the server310, for example, by referring to a table730ofFIG. 7. In this case, the server310may transfer the packet P7 to each of the second user420and the fifth user720through connecting information of the second user420corresponding to the source identifier Src3 and connecting information of the fifth user720corresponding to the source identifier Src8, which are designated in the packet P7.

InFIGS. 4-8, while the same names are given to the packets transmitted from the first user410to the server310(e.g., the packets P3 and 4 transmitted from the first user410to the server310inFIG. 5) and the packets transmitted from the server310to another user (e.g., the packets P3 and P4 transmitted from the server310to the second user420), the packets transmitted from the server310to the other user are not necessarily the same as the packets transmitted from the first user410to the server310because the server310may modify the packets received from the first user410or may generate new packets based on data or information included in the packets received from the first user410.

FIG. 8illustrates an example of an extended container format based on an extended transfer protocol according to at least one example embodiment.FIG. 8illustrates a container format800of an extended transfer protocol of a real-time transport protocol (RTP). Here, destination synchronization sources (dSSRCs) may be newly defined to manage destinations to correspond to synchronization sources (SSRCs) for managing sources in the extended transfer protocol of the RTP. Here, a first box810indicated with dotted lines may represent a field for recording dSSRCs (D-SSRCs) in an RTP packet header. Here, recording a dSSRC may represent recording an identifier of the dSSRC. Also, D-CNT for counting a number of dSSRCs to correspond to CC for counting a number of SSRCs may be newly defined. InFIG. 8, a second box820indicated with dotted lines may represent a field for counting a number of dSSRCs. In this case, a client may designate another client to which a packet is to be transferred by adding a dSSRC to the packet, and the server310may verify a destination to which the packet is to be transferred through the dSSRC included in the packet received from the client and may transmit the packet to the verified destination.

FIG. 9is a flowchart illustrating an example of a group call method of a client according to at least one example embodiment. The group call method ofFIG. 9may be performed by the computer apparatus200that implements a client configured to participate in a group call service. In this case, the processor220of the computer apparatus200may be configured to execute a control instruction according to a code of at least one program or a code of an OS included in the memory210. Here, the processor220may control the computer apparatus200to perform operations910to940included in the method ofFIG. 9in response to a control instruction provided from a code stored in the computer apparatus200.

Referring toFIG. 9, in operation910, the computer apparatus200may establish a media session with a server providing a group call service such that a first client participates in an instance of the group call service. The first client may be implemented by the computer apparatus200through a computer program installed and executed on the computer apparatus200for a group call. To participate in a specific instance for the group call, the computer apparatus200may establish the media session with the server.

In operation920, the computer apparatus200may transmit, to the server, at least one first packet including a source identifier of the first client to transfer data for the group call of the first client to second clients participating in the instance through the media session. Here, the first packet may refer to a packet of which a destination is not designated. For example, in the container format800ofFIG. 8, if D-CNT is zero in, a dSSRC is not included in a packet and the packet may be the first packet of which the destination is not designated. The at least one first packet may be transferred to each of the second clients participating in the instance in a form of broadcast through the server.

In operation930, the computer apparatus200may provide a user interface for receiving a selection on a portion of the second clients. The second clients participating in the instance may correspond to participants that participate in the instance of the group call. The user interface may include functions for selecting a portion of participants that participate in the instance of the group call service. Depending on example embodiments, a portion of the participants may be selected by grouping a portion of the participants participating in the instance into a single small group and selecting the small group.

In operation940, the computer apparatus200may transmit, to the server, at least one second packet including source identifiers of the selected portion of the second clients as destination information through the user interface. Here, the source identifier may be information previously received from the server and the second packet may refer to a packet of which a destination is designated. For example, in the container format800ofFIG. 8, if D-CNT is not zero in, it may represent a case in which a dSSRC is recorded and the recorded dSSRC may represent a destination of the packet. The at least one second packet may be transferred to the portion of the second clients corresponding to the destination information in a form of unicast or multicast through the server. If the computer apparatus200is unaware of source identifiers of the second clients, the computer apparatus200may receive, from the server, source identifiers of the second clients participating in the instance through communication with the server or the source identifiers of the selected portion of second clients through the user interface and may add the received source identifiers to the at least one second packet.

As described above, the at least one second packet may be generated according to an extended transfer protocol of an RTP and transmitted to the server. Here, the at least one second packet generated according to the extended transfer protocol of the RTP may include a field for recording at least one dSSRC corresponding to destination information. Also, the at least one second packet generated according to the extended transfer protocol of the RTP may further include a field for counting a number of dSSRCs.

FIG. 10is a flowchart illustrating an example of a group call method of a server according to at least one example embodiment. The group call method ofFIG. 10may be performed by the computer apparatus200that implements a server configured to provide a group call service. In this case, the processor220of the computer apparatus200may be configured to execute a control instruction according to a code of at least one program or a code of an OS included in the memory210. Here, the processor220may control the computer apparatus200to perform operations1010to1050included in the method ofFIG. 10in response to a control instruction provided from the computer apparatus200.

Referring toFIG. 10, in operation1010, the computer apparatus200may establish a media session with a first client such that the first client participates in an instance of a group call service. Here, the first client may be implemented by a terminal of a first participant through a computer program installed and executed on the terminal of the first participant for a group call. To participate in a specific instance for the group call, the server and the terminal of the first participant may establish the media session.

In operation1020, the computer apparatus200may receive, from the first client, at least one first packet including a source identifier of the first client through the media session. Here, the first packet may refer to a packet of which a destination is not designated. For example, in the container format800ofFIG. 8, if D-CNT is zero, a dSSRC is not included in a packet and the packet may be the first packet of which the destination is not designated.

In operation1030, the computer apparatus200may transfer the at least one first packet to each of second clients participating in the instance in a form of broadcast. That is, the first packet may be transferred to each of all the participants participating in the instance.

In operation1040, the computer apparatus200may receive, from the first client, at least one second packet including, as destination information, source identifiers of a portion of the second clients participating in the instance through the media session. The second packet may refer to a packet of which a destination is designated. For example, in the container format800ofFIG. 8, if D-CNT is not zero in, it may represent a case in which a dSSRC is recorded and the recorded dSSRC may represent a destination of the packet. If the first client is unaware of the source identifiers of the second clients, the first client may request the computer apparatus200for the source identifiers of the second clients. In this case, in response to the request from the first client, the computer apparatus200may transmit, to the first client, source identifiers of the second clients participating in the instance or source identifiers of a portion of second clients selected by the first client.

In operation1050, the computer apparatus200may transfer the at least one second packet to a second client corresponding to a source identifier included in the second packet in a form of unicast or multicast. Therefore, the second packet may be transferred to a portion of the second clients designated by the first client instead of being transmitted to all of the second clients that participate in the instance of the group call service.

Although the example embodiments are described based on examples in which a participant designates a destination, for example, a source identifier, a server may arbitrarily designate a destination of a specific packet depending on example embodiments. For example, if a specific participant desires to call audio or video during a group call, the server may designate a destination of a packet for corresponding audio or video as the corresponding specific participant such that the corresponding audio or video may be transferred to the specific participant.

According to some example embodiments, it is possible to transmit data in a form of unicast or multicast to a portion of participants participating in an instance of a group call during the progress of the corresponding instance.