JP4867803B2 - Network communication system - Google Patents

Description

  The present invention relates to a network communication system in which a plurality of terminals are connected to each other.

  Conventionally, various conference systems for performing conferences between remote locations have been disclosed. In such a conference system, various proposals have been made to ensure audio quality (see, for example, Patent Document 1 and Patent Document 2). The device of Patent Document 1 can ensure optimal call quality at any terminal by simultaneously distributing data corresponding to the processing capability on the receiving side to a plurality of terminals. In the device of Patent Document 2, the server device assigns the number of terminals to the audio data and distributes the audio data, thereby performing level adjustment according to the number of terminals on the receiving side and ensuring audio quality.

In addition, since the conference is performed at multiple points, the state of each device (the presence or absence of a speaker, the presence or absence of connection, etc.) becomes a problem. Thus, a technique is disclosed in which a participant can specify a speaker (see, for example, Patent Document 3). The device of Patent Document 3 distributes determination data for the presence / absence of speech as data different from audio data, and identifies a speaker.
JP 2005-277949 A JP 2003-23499 A Special table 2003-506906 gazette

  However, according to the devices of Patent Documents 1 and 2, the state of each device cannot be detected. On the other hand, according to the configuration of Patent Document 3, traffic different from voice data is generated, so that the network load increases. As a result, real-time communication is hindered.

  Therefore, an object of the present invention is to provide a network communication system that can specify the state of each device in real time without increasing the network load.

  The network communication system according to the present invention is a network communication system including a plurality of terminals connected via a network, and the terminals store identification information of other terminals and information indicating the states of the other terminals. A storage unit, a detection unit for detecting the state of the terminal of itself, identification information of the terminal of itself, information indicating the state of the terminal of the terminal, and identification information of other terminals stored in the storage unit, and A communication unit that transmits information indicating the state of another terminal as extended information included in a predetermined protocol, and when the communication unit receives the extended information from another device, the communication unit stores its own terminal based on the extended information. When updating the information stored in the communication unit and transmitting the extended information including the information of the terminal itself to the other terminal that transmitted the extended information to the communication unit, the identification information of the other terminal is transmitted. And characterized by comprising a control unit configured to send without including the information indicating the state of the other terminal.

  In this configuration, each terminal records information indicating the state of another device in a memory. Each device includes information indicating the status of the device itself and information indicating the status of the other device recorded in the memory in extension information (RTP extension header) included in a predetermined protocol (for example, RTP (Real-time Transport Protocol)). Send as. On the receiving side, the recorded contents of the memory are updated based on the received extended information. Also, information indicating the status of the terminal is not transmitted to the terminal that has transmitted the extended information. That is, information indicating the state of the transmission destination device is not included in the extension header. As a result, all terminals in the system can record the status of other devices, and information indicating the status of other devices is described in the extension header included in the RTP packet. There is no increase.

  Further, according to the present invention, the terminal is an audio conference terminal including a sound collection unit and a sound emission unit, and the communication unit includes the sound collected by the sound collection unit in the predetermined protocol. And the detection unit detects the level of the sound collected by the sound collection unit, and displays information indicating whether the level is equal to or higher than a predetermined threshold, the state of the terminal of the terminal itself. It is included in the information to show.

  In this configuration, each terminal includes a sound collection unit and a sound emission unit. Each terminal detects the level of collected sound and detects whether the level is equal to or higher than a predetermined threshold. If it is equal to or greater than a predetermined threshold, it can be determined that there is a speaker, and information indicating that it is equal to or greater than the threshold is included in the information indicating the state of the device to detect the presence or absence of a speaker at each terminal. it can.

  Furthermore, the present invention is characterized in that the control unit is set in the communication unit so as to transmit the extended information including control information for controlling other terminals.

  In this configuration, the extended information is transmitted including information for controlling other devices. For example, the volume control of another device is performed.

  Furthermore, the present invention is characterized in that the plurality of terminals are connected in a hierarchy, and the detection unit includes the hierarchical level of the terminal in the information indicating the state of the terminal.

  In this configuration, the terminals are connected in a hierarchy (cascade connection). Information indicating the hierarchical level is transmitted and received between the terminals as the state of the own device. By transmitting and receiving information indicating the hierarchical level, it is possible to quickly detect a malfunction (such as a loop or a hierarchical limit over) in the network.

In addition, according to the present invention, the control unit stores the information when there is information on a terminal that is not included in the received extended information among information on other terminals stored in the storage unit of the terminal. The terminal information is deleted from the section .

  According to the present invention, the state of each device can be specified in real time without increasing the network load.

  A network communication system according to an embodiment of the present invention will be described.

  FIG. 1 is a block diagram showing a configuration of a network communication system. The voice communication system includes a conference server 10, conference terminals 11A to 11D, and a PC 12A connected via a network 200 that is the Internet. The conference terminals 11A to 11D are installed in conference rooms 101A to 101D, which are different places. The PC 12A is installed in the conference room 101A. The conference server 10 may be installed in any conference room, or may be installed in another location. Each device is actually connected by encrypted communication such as VPN via a router.

  FIG. 2 is a block diagram showing the configuration of the conference terminal 11A. The conference terminals 11A to 11D all have the same configuration and function. Therefore, in FIG. 2, the configuration of the conference terminal 11A is shown as a representative.

  The conference terminal 11A includes a control unit 111, a network I / F 112, a sound emission mixer 113, a sound detection unit 114, a transmission mixer 115, a memory 116, a speaker SP, and a microphone MIC. In this embodiment, an A / D converter, a D / A converter, a power amplifier, and the like are omitted, and all audio signals transmitted through the apparatus are digital audio signals.

  The control unit 111 comprehensively controls the conference terminal 11A. In addition, the network I / F 112 is controlled to transmit the sound collected by the own apparatus to the network using a predetermined protocol. In this embodiment, RTP is used as a protocol for data transmitted and received between conference terminals.

  FIG. 3 is a diagram illustrating a configuration example of a transmission packet according to RTP. As shown in the left column of the figure, the RTP transmission packet includes an RTP standard header, an RTP extension header, and audio data. The RTP standard header is a header conforming to general-purpose RTP, and information indicating whether or not an extension header is included in the packet, a time stamp, and the like are described in the RTP standard header.

  The RTP extension header is a unique extension header used in the network communication system of the present embodiment. As shown in the right column of the figure, the RTP extension header includes various data such as a header identifier, a data length, the number of connections, a version, a site identifier, and site additional information.

  The header identifier is used to identify the RTP extension header. The data length represents the data length of the RTP extension header. The number of connections indicates the number of terminals connected to the own device. In the present embodiment, each conference terminal is connected to one or a plurality of conference terminals by mesh connection or cascade connection (see FIG. 5). In the example shown in FIG. 1, each conference terminal is connected to three terminals and performs three-channel communication. The version indicates the version of the RTP extension header.

  The base identifier is used to identify base additional information included thereafter. The base additional information indicates information such as the level of sound collected at each base (conference room) and the state of the device. The control unit 111 of the conference terminal 11A records the state of the conference terminal at each site in the memory 116 based on this site additional information. Details will be described later.

  In order to generate the above RTP extension header, the control unit 111 acquires the level of collected sound detected by the sound detection unit 114 and acquires a threshold determination result.

  The voice detection unit 114 is set with a threshold value for determining the voice level when the speaker speaks, and determines whether or not the level of the collected voice input is equal to or higher than the threshold value. If the level of the collected voice is equal to or higher than the threshold, the voice detection unit 114 outputs a threshold determination result indicating that a speaker is present to the control unit 111. The control unit 111 includes the level of the collected voice detected by the voice detection unit 114 and the threshold determination result in the base additional information and transmits the base additional information to another device via the network I / F 112.

  Here, the network I / F 112 generates an RTP packet from the audio signal input from the transmission mixer 115 and the threshold determination result according to the control of the control unit 111. In the case of cascade connection (see FIG. 5B), the transmission mixer 115 receives an audio signal input from the microphone MIC and an RTP from each site (conference terminals 11B to 11D) input from the network I / F 112. The audio signal included in the packet is mixed and output to the network I / F 112. A separate RTP packet is transmitted to each conference terminal.

  The transmission mixer 115 selects an audio signal to be mixed under the control of the control unit 111. For example, when transmitting an RTP packet to the conference terminal 11B in a cascade connection, the control unit 111 collects the audio signal included in the RTP packet received from the conference terminal 11C and the conference terminal 11D and the sound from the own device. The transmission mixer 115 is set so as to mix the collected sound signal of the microphone MIC. Then, the network I / F 112 generates an RTP packet and transmits it to the conference terminal 11B.

  FIG. 4 is a conceptual diagram showing an aspect of audio signal transmission / reception. As shown in the figure, the control unit 111 of the conference terminal 11A transmits a separate RTP packet to each conference terminal. That is, the conference terminal 11B collects the audio signal s13 contained in the RTP packet received from the conference terminal 11C by the transmission mixer 115, the audio signal s14 contained in the RTP packet received from the conference terminal 11D, and the own device. The microphone MIC collected sound signal s11 is mixed to generate audio data, and further information on the extension header included in the RTP packet received from the conference terminal 11C and the extension header included in the RTP packet received from the conference terminal 11D An extension header is generated on the basis of the above information and the information of its own device, and is transmitted as an RTP packet. Similarly, the conference terminal 11C generates audio data by mixing the audio signal s12 of the conference terminal 11B, the audio signal s14 of the conference terminal 11D, and the collected sound signal s11 of the own device, and outputs the audio data from the conference terminal 11B. The extension header is generated based on the extension header information, the extension header information from the conference terminal 11D, and the information of the own apparatus, and transmitted as an RTP packet. In addition, the conference terminal 11D generates audio data by mixing the audio signal s12 of the conference terminal 11B, the audio signal s13 of the conference terminal 11C, and the collected sound signal s11 of the own device, and outputs the audio data from the conference terminal 11B. An extension header is generated based on the extension header information, the extension header information from the conference terminal 11C, and the information of the own device, and is transmitted as an RTP packet.

  The sound emission mixer 113 of the conference terminal 11A mixes the audio signal included in the RTP packets received from the other conference terminals 11B to 11D and outputs the audio signal to the speaker SP. The speaker SP is based on the input audio signal. Release sound. In the example of FIG. 4, the audio signals s12, s13, and s14 included in the RTP packets received from the other conference terminals 11B to 11D are mixed and emitted. When a plurality of speakers are provided, it is possible to emit the sound of each site from each speaker without mixing.

  Each conference terminal performs transmission / reception of the RTP packet as described above, thereby realizing an audio conference.

  Next, the connection mode of the conference terminals 11A to 11D will be described. FIG. 5A is a diagram showing a mode in which conference terminals 11A to 11D are mesh-connected, and FIG. 5B is a mode in which conference terminals 11E to 11J having the same configuration as the conference terminals 11A to 11D are cascade-connected. FIG. 1 shows only the configuration in which the conference terminals 11A to 11D are connected, but FIG. 5B shows the configuration in which the conference terminals 11E to 11J are connected for convenience of explanation.

  In the mesh connection shown in FIG. 2A, the conference terminals are connected to each other and transmit / receive RTP packets. In the mesh connection shown in FIG. 4A, four connections are shown. Of course, the number of connections may be smaller than this, or the number of connections may be larger if more than one can be connected due to the specifications of the device. .

  In the cascade connection shown in FIG. 5B, each conference terminal is connected to three or less terminals and transmits and receives RTP packets. Note that the number of connections may be further increased when a plurality of terminals can be connected due to the specifications of the apparatus. In addition, in the cascade connection of FIG. 5B, six connections of the conference terminals 11E to 11J are shown as a whole system, but it is needless to say that the number may be smaller or larger than this number. In the cascade connection, the connection is hierarchical. For example, in the example of FIG. 5B, when the conference terminal 11F is considered as the center, and the conference terminal 11H is the upper layer, the conference terminal 11E and the conference terminal 11G are the lower layer. The conference terminal 11I and the conference terminal 11J are lower layers of the conference terminal 11H. Hierarchy management is performed by the number of communication hops described later.

  FIG. 6 is a diagram showing a transmission / reception mode of the extension header information included in the RTP packet. First, FIG. 6A shows a transmission / reception mode of extension header information in mesh connection. Actually, RTP packets are transmitted and received between the conference terminals, but FIG. 4A shows an example in which the conference terminal 11A receives the RTP packets for convenience of explanation.

  The conference terminal 11A receives the RTP packet from each conference terminal. The RTP packet received from the conference terminal 11B includes information on the conference terminal 11C and the conference terminal 11D as information on other terminals, in addition to information on the conference terminal 11B (level of collected sound and threshold determination result). . The RTP packet received from the conference terminal 11C includes information on the conference terminal 11B and the conference terminal 11D as information on other terminals, in addition to information on the conference terminal 11C (level of collected sound and threshold determination result). ing. Similarly, the RTP packet received from the conference terminal 11D includes information on the conference terminal 11B and the conference terminal 11C as information on other terminals, in addition to information on the conference terminal 11D (level of collected sound and threshold determination result). It is. Each conference terminal records the state of the conference terminal at each site in the memory 116 in order to transmit information of other terminals, and transmits an RTP packet in accordance with the record in the memory 116.

  FIG. 7 is information indicating the state of the conference terminal at each site recorded in the memory 116. Up, Left, and Right in the upper column of the figure indicate relative positions on the array, and each indicates identification information (node link information) of a terminal connected to the own apparatus. Note that in this embodiment, node links are managed separately for Up, Left, and Right in order to perform three-channel communication. However, when performing multi-channel communication, additional node link information is added. do it.

  The node identification information is identification information of the own device. The node identification information may be any value as long as it is a value unique to each terminal. For example, a MAC address can be used. Since the node identification information is transmitted as the base identifier shown in FIG. 3 from the other apparatus, the node identification information of the other apparatus is used as the node link information. For example, in the example shown in FIG. 6A, the conference terminal 11A records the node identification information of the conference terminal 11C as Up, the node identification information of the conference terminal 11B as Right, and the node of the conference terminal 11D as Left. Record identification information. In the example of FIG. 6B, a larger number of terminals are connected as a whole system. However, since the number connected to each terminal is three or less, the number recorded as node link information is as described above. Similarly, there are three. A specific example of the node link information when the connection shown in FIG. 6B is performed will be described with reference to FIG. FIG. 10 is a diagram illustrating a specific example of node link information in cascade connection. Here, the conference terminal 11F is considered as a center. In the figure, for convenience of explanation, the configuration number of the conference terminal is attached to the node identification information, but of course, the MAC address or the like is actually used.

  First, since the conference terminal 11H is connected to the upper side of the conference terminal 11F, 1 indicating the information of the conference terminal 11H described in the next lower element is described in the Up of the node link information. Similarly, Left indicates 4 indicating information of the conference terminal 11E described in the lower four elements, and Right indicates 5 indicating information of the conference terminal 11G described in the five lower elements. Describe. In addition, since the conference terminal 11I and the conference terminal 11J are connected to the lower side of the conference terminal 11H, in the node link information of the conference terminal 11H, -1 indicating the information of the conference terminal 11F is described in Up, and Left 1 indicates 1 indicating the information of the conference terminal 11I described in the next lower element, and 2 indicates 2 indicating the information of the conference terminal 11J described in the next lower element. In the conference terminals 11I, 11J, 11E, and 11G, since there is no terminal connected to the lower side, only Up is described in the node link information.

  Next, the status of each terminal is recorded in the node meta information. As shown in FIG. 7, for example, the state of each terminal includes a threshold determination result, a background noise level, a device state, the number of communication hops, and a CDB (Command Descriptor Block). The threshold determination result is information indicating the presence / absence of a speaker as described above. The background noise level is information indicating the level of an audio signal when no speaker is present. The device status is information indicating, for example, whether the terminal is muted or the microphone is malfunctioning. The communication hop number is information indicating in which hierarchy the terminal exists. Referring to the example shown in FIG. 10, the number of communication hops of the conference terminal 11 </ b> F is 0 because it is the own device. Since the conference terminal 11H is one level higher, the number of communication hops is 1, and since the conference terminal 11E and the conference terminal 11G are one level lower, the number of communication hops is 1. Further, since the conference terminal 11I and the conference terminal 11J are one level lower than the conference terminal 11H, the number of communication hops is two. In the mesh connection, since the terminals are connected to each other, it is not necessary to manage the number of communication hops. The CDB is command information for controlling another device. For example, when performing volume control of another device, the CDB is transmitted as volume control information including the CDB in the RTP packet. On the receiving side, the control unit 111 records this CDB in the memory 116 and performs volume control. Note that the volume control includes control of the level of the audio signal to be transmitted and control of the level of the received audio signal. That is, the levels of the transmission audio signal and the reception audio signal can be controlled separately.

  When the control unit 111 receives an RTP packet from each conference terminal, the control unit 111 updates the recorded contents of the memory 116 shown in FIG. For example, when node identification information that exists in the RTP extension header information but is not recorded in the memory 116 is received, the base additional information related to the node identification information is recorded in the node meta information. On the other hand, if it is recorded in the node meta information of the memory 116 but the node identification information of the terminal is not included in the RTP extension header information, the connection of the terminal is deleted from the system as it is disconnected from the system.

  Here, for example, when the connection between the conference terminal 11B and the conference terminal 11C is interrupted, the extended header information received from the conference terminal 11B does not include the information on the conference terminal 11C. Further, the extension header information received from the conference terminal 11C does not include information on the conference terminal 11B. However, the extended header information received from the conference terminal 11D includes information on the conference terminal 11B and the conference terminal 11C. Therefore, the conference terminal 11A can detect that the connection between the conference terminal 11B and the conference terminal 11C is disconnected by comparing the extension header information received from each conference terminal.

  Similar updating is performed in the cascade connection. FIG. 6B is a diagram showing a transmission / reception mode of extension header information in cascade connection. Each conference terminal transmits its own information to the connected terminal. For example, the conference terminal 11E transmits information on its own device to the conference terminal 11F. The information on the conference terminal 11E is transmitted from the conference terminal 11F to the conference terminals 11G to 11H on the lower layer in order. In addition, the conference terminal 11F transmits information on the own device to the conference terminal 11E, the conference terminal 11G, and the conference terminal 11H. Here, in addition to the information on the conference terminal 11G and the conference terminal 11H, the conference terminal 11F receives the information on the conference terminal 11I and the conference terminal 11J connected to the lower layer of the conference terminal 11H. All the information of the conference terminal 11F to the conference terminal 11J is transmitted. Therefore, even in the cascade connection, each conference terminal receives information on all conference terminals connected in the system. In addition, since the control part 111 of each conference terminal does not send back the information received from the terminal, information does not loop.

  Here, when a problem occurs in the cascade connection and, for example, the conference terminals 11J and 11E are connected, the information on the conference terminal 11J is transmitted from the conference terminal 11J to the conference terminal 11E. That is, the conference terminal 11E receives the same terminal information from a plurality of terminals. Therefore, each conference terminal can detect that a loop has occurred by comparing a plurality of received extension header information.

  Further, according to the network communication system according to the embodiment of the present invention, by recording the information shown in FIG. 7 and FIG. 10 in each terminal, when a next meeting is performed between terminals once participating in the meeting, The connection procedure can be simplified. In each terminal, the terminal participating in the conference and the connection mode are recorded. For example, in the example of FIG. 5A, conference terminals 11A to 11D participate and information indicating mesh connection is recorded. In the example of FIG. 5B, the conference terminals 11E to 11J participate and record information indicating the cascade connection and the connection destinations (the conference terminals 11E, 11H, and 11G in the conference terminal 11F). Keep it. Thus, when the user starts the conference next, when the user performs the conference participation operation at any of the terminals (for example, the conference terminal 11F), each terminal (the conference terminals 11E, 11H, And 11G), and the connection destination (conference terminal 11H) is further connected to other terminals (conference terminals 11I and 11J). As a result, connections with all terminals can be easily established. In each terminal, the above information may be recorded as information easy to understand for the user as a call history, an address book, or the like. When recording as an address book, for example, a name such as “branch liaison meeting” may be added and recorded.

  Next, the function and configuration of the conference server 10 in FIG. 1 will be described. FIG. 8 is a block diagram showing the configuration of the conference server 10. As shown in the figure, the conference server 10 includes a communication control unit 150, a schedule control unit 151, a speaker information management unit 152, a network I / F 153, and a display unit 154.

  The communication control unit 150 communicates with the conference terminals 11A to 11D via the network I / F 153. Specifically, the communication control unit 150 has an address management function and a proxy server function, and controls establishment and cancellation of a communication network between the conference terminals 11A to 11D. Further, the communication control unit 150 detects the presence of the speaker from the threshold determination result of each conference terminal and records it as presence information in the speaker information management unit 152.

  The schedule control unit 151 has a timer function, stores a schedule of conferences and the like input in advance, and notifies the communication control unit 150 to perform communication network establishment control when the conference start timing is detected. In addition, when the conference end timing is detected, the communication control unit 150 is notified to perform communication network release control. In addition, the schedule control unit 151 gives time information to the speaker information management unit 152.

  The speaker information management unit 152 acquires the presence information of each conference terminal 11A to 11D via the communication control unit 150, associates the presence information with time information from the schedule control unit 151, and stores the presence status data in time series. Generate. At this time, the presence information and the conference terminal are associated with each other. The generated presence status data is given to the display unit 154 and stored, and if requested from the PC 12A or the like via the communication control unit 150, the presence status data is transmitted to the request source.

  The display unit 154 is composed of a liquid crystal panel or the like, and performs a graphical display so that changes in the speaker can be visually acquired based on time information given from the speaker information management unit 152 and presence status data. Thereby, the person in the position where the conference server 10 is installed can easily and visually confirm the situation of the speaker.

  Actually, each conference terminal holds the IP address of the conference server 10, and each conference terminal manages presence information by transmitting SIP REGISTER to the conference server 10.

  Next, in FIG. 1, a PC 12A is a so-called general-purpose personal computer and includes a network I / F, a display unit, and the like. The PC 12A is installed at the same base as the conference terminal 11A, and is operated by a user (for example, a conference manager) of the conference terminal 11A while performing a conference.

  The PC 12A receives presence information from the conference server 10 and displays it on its display unit. FIG. 9 is a diagram illustrating transmission / reception of presence information in a network communication system. As shown in the figure, the PC 12A receives presence information from the conference server 10 using, for example, the HTTP protocol. By receiving the presence information, it is possible to visually recognize which sites are participating in the conference and the participation status of each site.

  In addition, the PC 12A makes a SYSLOG transmission request to any conference terminal in the system. In the example of the figure, a request is made to the conference terminal 11A installed at the same base. The PC 12A and the conference terminal 11A communicate via the network 200, but may of course communicate via a LAN. In practice, a SYSLOG transmission request is notified using telnet or the like.

  Upon receiving the SYSLOG transmission request, the conference terminal 11A periodically transmits the contents recorded in the memory 116 to the PC 12A as SYSLOG. In addition, when the memory 116 is updated, the SYSLOG may be transmitted immediately. The PC 12A displays the contents of the received SYSLOG on the display unit. Thereby, the state of each base in the system can be easily determined.

  In addition, the PC 12A periodically transmits a ping to the conference terminal 11A. This ping is used as information on whether or not the PC 12A is hung up in the conference terminal 11A. In other words, the conference terminal 11A includes a timer inside and resets the timer every time a ping is received. When the timer has timed out, the transmission of SYSLOG is stopped since the transmission of ping is interrupted. This prevents a situation where SYSLOG continues to be sent. Note that the transmission of the ping is not an essential configuration in the present invention. In addition, it is not limited to ping as long as it can confirm whether or not the PC 12A is hung up.

  The PC 12A transmits a SYSLOG transmission stop request to the conference terminal 11A when the management of each terminal is stopped, such as at the end of the conference. Thereby, the conference terminal 11A stops the transmission of SYSLOG. If the conference terminal 11A is disconnected from the system during the conference, the PC 12A may make a SYSLOG transmission request to the other conference terminals.

  The functions of the PC 12A are realized by software (application).

  The configurations of the PC 12A and the conference server 10 are not essential in the present invention. If the conference terminal itself has a display unit such as an LCD, presence information and terminal status can be displayed on the conference terminal.

  If the conference terminal can detect the speaker position, speaker position information and the like may be transmitted and received. When directivity can be controlled on the sound emission side, control is performed so that sound is emitted from a specific direction (sound is emitted from the speaker position) by transmitting and receiving speaker position information. be able to.

It is a block diagram which shows the structure of a network communication system. It is a block diagram which shows the structure of 11 A of conference terminals. It is a figure which shows the structural example of the transmission packet which concerns on RTP. It is the conceptual diagram which showed the aspect of transmission / reception of an audio | voice signal. It is a figure which shows the connection aspect of a conference terminal. It is a figure which shows the transmission / reception aspect of the information of the extension header contained in a RTP packet. This is information indicating the state of the conference terminal at each site recorded in the memory 116. 2 is a block diagram illustrating a configuration of a conference server 10. FIG. It is a figure which shows transmission / reception of presence information in a network communication system. It is a figure which shows the specific example of the node link information in cascade connection.

Explanation of symbols

10-conference servers 11A to 11D-conference terminal 12A-PC

Claims (5)

A network communication system comprising a plurality of terminals connected via a network,
The terminal includes a storage unit that stores identification information of another terminal and information indicating the state of the other terminal;
A detection unit for detecting the state of its own terminal;
The predetermined protocol includes identification information of the terminal itself, information indicating the state of the terminal itself, identification information of the other terminal stored in the storage unit, and information indicating the state of the other terminal. A communication unit that transmits as extended information;
When the communication unit receives extended information from another device, updates the information stored in the storage unit of its own terminal based on the extended information,
When transmitting the extended information including the information of the own terminal to the other terminal that has transmitted the extended information to the communication unit, the identification information of the other terminal and the information indicating the state of the other terminal are included. A control unit configured to transmit without
A network communication system comprising: The terminal is an audio conference terminal including a sound collection unit and a sound emission unit,
The communication unit transmits the voice collected by the sound collection unit as voice data included in the predetermined protocol,
The detection unit detects a level of sound collected by the sound collection unit, and includes information indicating whether the level is equal to or higher than a predetermined threshold in information indicating a state of the terminal of the terminal. The network communication system described in 1.   3. The network communication system according to claim 1, wherein the control unit sets the communication unit to transmit the extended information including control information for controlling another terminal. 4. The plurality of terminals are connected in a hierarchy,
The network communication system according to claim 1, 2, or 3, wherein the detection unit includes a hierarchical level of its own terminal in information indicating a state of the own terminal. The control unit deletes the information on the terminal from the storage unit when there is information on the terminal that is not included in the received extension information among the information on other terminals stored in the storage unit of its own terminal. the network communication system according to any one of claims 1 to 4.

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