Multimedia communications network

Multimedia communication network

Reference documents for related applications:

This application is related to Ahuja, Aravamudan, Ensor, Kut-hyar, Ramamuthy, Stuntebeck, and Weber applications [Ku-thyar 1-1-1-7]. The case was filed on the same day as this application. Filed in the Patent and Trademark Office.

The present invention relates to communication networks. More specifically, the present invention relates to multimedia communication networks that can be between two or more parties. Use a variety of media (for example, audio, video and data) to form an effective meeting.

The essential characteristics of face-to-face meetings can be simulated by a multimedia conference system. This conference system allows separate conference participants to use multimedia (such as audio, video, and data) to communicate with others at their work.

In the previous practice, this conference system consists of a set of complex and expensive computer workstations connected to each other with transmission equipment. Regardless of the communication between the workstations, these transmission equipment are only used as transmission machines. This decentralized structure is a serious problem, which restricts the system from becoming a universal, commercial, and feasible object. In the previous decentralized environment, each workstation has powerful multimedia data processing capabilities (including necessary branching and synchronization circuits), which is sufficient to provide conference participants with an effective meeting. This increases the cost of every customer who has the potential to use multimedia, who usually put multimedia outside of their interests and budget. In addition, the previous partial platform application can hardly become a long-term, flexible multimedia conference environment, because when the conference environment is used, at least one workstation must be turned on. It is very inconvenient for all participants to return to the meeting after they leave the meeting. It is also difficult to synchronize the different parts of the multimedia conference and give the participants in the dispersed environment appropriate sounds and images. In this situation, it is difficult to make multimedia connections between different communication devices. For example, two computers use different operating systems.

In addition to the above-mentioned decentralized structure, there are some centralized structures, which include more media bridges on the network than on local workstations. For example, the AT&T long-distance network includes some voice and video bridging capabilities, such as those included in the AT&T Alliance conference call service and AT&T Global Busine-ss Video Conferencing System Services. Although these services are useful long-distance communication services, this application has identified important areas that can be improved. This application found that it is difficult to achieve a flexible, long-term multimedia conference under the condition of a variable number of users and different media capabilities. Synchronous communication methods (such as telephone) and asynchronous communication methods (such as e-mail) are not easy to merge in previous multimedia communication systems. The previous multimedia communication system is also difficult to combine different communication devices used by different participants into an effective conference. It is difficult for participants with different multimedia communication capabilities to freely enter or leave a given multimedia conference. There is no convenient way to form an effective meeting among many potential users. For example, these users must use a complex network (such as a widespread local area network or a large area network, such as a telephone network). ) To connect together. For example, it is impossible to provide a multimedia communication service for long-distance communication transmission to the vast number of telephone consumers who use the current multimedia conference system.

The aforementioned problems can be solved by a multimedia communication network, which provides a shared multimedia working environment, the media of which can be accessed by one or more multimedia ports. In some periods, this multimedia communication network is composed of at least one conference room server on the network, and some ports that allow users to access the network are connected. This conference room server generates some special electronic circuit configurations on the network, which respond to commands issued by the user terminal connected to the media port. This electronic circuit configuration has pre-set characteristics created by network users, and has a pre-selected lifetime on the network, which meets the expectations of users who use this electronic circuit configuration to become an electronic multimedia conference . The electronic circuit configuration can be a data structure, which represents a controllable and sustainable virtual meeting room on the network. Meetings can be held in this conference room, which can accommodate any number of participants. They do not have to have the same communication capabilities in all media. These participants can join and leave the meeting held in the virtual meeting room. Even if all the attendees leave the meeting, the virtual meeting room remains in the network to be used by the same attendees or others to resume or continue the meeting later. The virtual meeting room can also be used by the same participants or others to make initial settings or continue other meetings. This virtual meeting room is an electronic analogy of a physical meeting place used to hold meetings.

Figure 1 is a multimedia network constructed using the present invention.

Figure 2 is a connection topology, including two multimedia workstations, which are connected through the middle part of the multimedia network in Figure 1.

Figures 3a-3d show virtual meeting rooms generated by the meeting room server in Figure 2.

Fig. 4 is a state diagram showing the operation of a meeting room server in Fig. 1 for a virtual meeting room on a network.

Fig. 5 is a state diagram showing the operation of a session manager in Fig. 2 for a virtual meeting room on a network.

Fig. 6 is a block diagram of a generalized media server. The server is related to a storage device. According to the present invention, the device helps to effectively maintain the characteristics of the virtual meeting room.

Detailed description:

Figure 1 shows a multimedia network that can selectively connect one or several devices so that data can be transmitted from one device to another. This device contains one or several multimedia workstations, for example, a pair of multimedia workstations (12, 14) in Figure 1. These multimedia workstations are connected to individual multimedia channels on the network (10), and can communicate with another workstation or other devices connected to the network through multifunctional media (for example, audio, video, and data). Other devices that can be internally connected to the network (10) in Figure 1, include cameras, video recorders (18), fax devices (20), telephones (22), and televisions. The telephone (22) can be a simple POTS telephone, ISDN telephone, cellular or other wireless telephone, or any other telex device (for example, personal communicator) in the sound range. Each device shown in Figure 1 is connected to the appropriate channel on the network.

The network (10) contains a number of servers, and this server uses a predetermined medium as a connection between the selected devices in Figure 1. The network (10) contains one or more meeting room servers 1, 2, ..., i, each of which is a repository of information related to the virtual meeting room on the network (10). The media server includes one or more data servers 1, 2, ..., j, one or more video servers 1, 2, ..., k, and one or more sound servers, 1, 2, ... ...,<img file="TW239248B_D0001.tif" />. The data server is respectively connected to the data input and output parts of the device in Figure 1. In the same way, the image server is respectively connected to the image output and input parts of the device in FIG. 1, and the sound server is selectively connected to the audio input and output parts of the device. The network (10) also contains one or more name servers 1, 2, ..., m. Each name server can store the addresses of devices connected to the network, and are used by the conference room server and media server The address of the network resource. This meeting room server can quickly respond to the information controlled by the name server to create a connection between the user and the virtual meeting room.

In the example of the present invention, the server in Figure 1 can be embedded in one or more UNIX systems in the form of software.^®On a workstation that is the benchmark (such as a workstation manufactured by Sun M-icrosystems). As described in more detail below, a controllable and stable virtual meeting room is created in the multimedia network (10) shown in Figure 1. It can provide flexible configuration multimedia conference effects in any desired direction between users on the network.

Figure 2 shows a graphical multimedia connection between workstations (12, 14) on a network (10). The workstation (12) contains a user interface (26), which may include a video interface on a computer. This interface can also include data input devices, such as keyboards, mice, pen-type input devices, and voice input devices. The user interface (26) is connected to the session manager (28). The session manager (28) mediates the operation of a group of media managers on the workstation. The session manager (28) is also a signal broker on the workstation, which sends signals to the network to generate or eliminate one or more virtual meeting rooms for workstation operators. The session manager (28) also sends a signal to the network to generate or eliminate some different conference configurations in the virtual conference room that the workstation operator can enter.

The workstation (12) also contains a group of media managers who are respectively related to some hardware devices and software programs that can produce output results on the media and receive input results from other conferences. The workstation (12) includes a data manager for receiving data generated by one or more application programs. The application programs on these workstations include a flat panel program, a word processing program, a drawing program, and other similar programs. The data manager (10) directs these data to other participants via the network, and this network connects to similar data managers on other multimedia workstations in the conference. The workstation (12) also includes an image manager (32) for receiving image signals generated by one or more imaging devices. The imaging devices on these workstations include cameras, video players, scanners, and other similar devices. The image manager (32) directs the image signal to other participants via the network (10) connected to the image manager of other multimedia workstations. Finally, the workstation (12) contains a voice manager, which is associated with one or more voice devices, such as phones, microphones, and other similar devices. In addition to sending signals from workstations (12) to other participants via the network (10), the multimedia manager (30, 32, 34) also receives signals from other participants, and sends messages to the workstations under the manager user. For example, managers (30, 32, 34) can display data and images on a TV or monitor, and make voice output by speakers. In other examples of the present invention, there can be other media managers on the workstation (12), such as a manager who controls the fax signals generated in the workstation (12) or received from the workstation (12).

The message between the session manager (28) and the data manager (30) is sent by the line (29); the message between the session manager (28) and the image manager (32) is sent by the line (31); the message is sent by the line (33) Send messages between the session manager (28) and the voice manager (34). Similarly, the workstation (14) contains a user interface (36) connected to the session manager (38). The workstation (14) also contains a data manager (40), a video manager, and a voice manager, which are respectively connected to the session manager by signal lines (39), (41), and 43). These workstations (12, 14) can be UNIX^®Computers or workstations, such as workstations manufactured by Sun Microsystem and other similar computers. The administrator and user interface may be software programs on the computer.

A user terminal (such as the workstation (12, 14) in Figure 2) is connected to the multimedia port of the network (10). The multimedia signal from the terminal connected to the multimedia port is received by the multimedia port. An example of a multimedia port The multimedia messages are also directed to individual terminals connected to the multimedia port. The details of how the message transmission of the workstations (12, 14) are connected to the multimedia port on the network are shown in Figure 2 and described below.

In a multimedia connection between the workstations (12) and (14), the session manager (28) of the workstation (12) is properly connected with the session manager of the workstation (14) via the network. Each multimedia workstation is associated with a conference room server as shown in Figure 1. In the example of Figure 2, the workstations (12, 14) are associated with the same conference room server (48), which may be the conference room server shown in Figure 1.

The connection setting between the workstations (12, 14) is that the workstation user first creates a fixed virtual meeting room under the meeting room server. The command is from the session manager (28 or 38) via the line (45 or 46). ) Is delivered to the server (48). This virtual meeting room is composed of a data structure in the meeting room server (48). The server represents the exact computer resources on the connection and sends messages between the workstations (12, 14). For example, those resources include some or all of the memory associated with the conference room server, computer files, database tables, and other memory or storage capacity. In the network (10), each meeting room server can create more than one meeting room. Each virtual meeting room is given a unique identification, which allows qualified users to enter the meeting room. The virtual meeting room may contain the identity of the server, which serves as an effective connection between the workstations (12, 14) of different media. In addition, the virtual meeting room also contains the identities of the participants in it. In the virtual meeting room, one or more meetings can be held, and each one is given a unique identification and stored in the virtual meeting room. Each virtual meeting room also contains a piece of information about the access rights of eligible participants, who are allowed to use this room. In some situations, it is advantageous for a virtual meeting room to contain information about the length of time it has been used on the Internet. For example, in a situation where the network is a telephone network, it is an advantage that the virtual meeting room contains the data of the original generation time and the time spent in order to actually hold the meeting. These materials are for customers who use pay phones to use virtual meeting rooms to hold meetings and store information about the meeting on the Internet.

Figures 3a-3d are illustrations of some virtual meeting rooms generated by the meeting room server (48) (Figure 2). In the example in Figure 3a, the conference room is composed of a designated area in the server memory. A unique virtual meeting room body is shown at location (49). The right to enter the virtual meeting room is stored at location (51). These access rights specify who is allowed to use this virtual meeting room. The reserved attributes are stored in location (53). The reserved attributes may include information about who reserved the virtual meeting room, the time the room was reserved, and the identity of the media server to be used. Users whose reservation attributes cannot be identified will not be able to use this room during the reservation period. The reserved conflicts can be resolved with some previously configured permutations. When there is no conflict, the virtual meeting room can be reserved more. A statement identifying the characteristics of the m media servers associated with the virtual meeting room (47) is stored at the location (55). As shown in Figure 3b, the statement (59) of each server consists of a designated location that uniquely identifies the server. Those server statements also contain connection information (61), for example, the network location of individual servers. This server statement also contains information about who has the right to access a particular server (63), and payment information about the usage level of each paying user of the server (65), which corresponds to the aforementioned reserved attributes of this server Reserved data (67), and service statement (69), which can define a particular type of voice, video or data device controlled by this server, for example, voice message, voice message service, NTSC video (compressed and uncompressed) , Bulletin board services, games, weather-news, and other similar devices.

This room (47) also contains expressions about meetings between a group of participants. Identify the use of the virtual meeting room to hold or store the presentations of such n meetings held in the location (71), access rights (73), payment information (75), and one or more participant presentations. As shown in Figure 3d, each participant's statement in Figure 3c contains a unique identifier (79), which has status information (81) about whether the participant is using the conference room, and indicates the transmission media that the participant can use A static media statement (83) indicating the dynamic media statement (85) of the transmission media that the participant is using, and a profile that contains information about the user's use of the Internet, for example, the participant only participates in part The time of the meeting, the resources used by the participants during the meeting, and whether and how the participants paid. The server (48) can contain a number of meeting rooms. Each conference room can contain any number of servers, any number of meetings, and any number of participants in each meeting. Each participant can communicate with one or more composite communication media, such as voice, video and data.

The virtual meeting room generated on the meeting room server has the characteristic of persistence, which means that the data structure defined by the virtual meeting room can remain in the network for a time predetermined by the network user. Even if no user is connected to the meeting room or the network, the virtual meeting room can still stay on the network. Furthermore, the time that the virtual meeting room remains on the network can be controlled by one or more users of the virtual meeting room. This reserved conference room is also an organization, which can record pre-selected events that occur during multimedia or other conferences. After one or more participants set the time in advance, these events are stored in the network, regardless of whether the participants are actually on the Internet or using the virtual meeting room. For example, when the multimedia network is a telephone network, all participants may be in a certain predicament. Information about the conference selected by the participant will be stored on the network, waiting for any participant to come back in the future. Enable. This storage capability allows the meeting to be suspended and then resumed at the same point as the suspension. Newly-arrived participants can also join an existing conference and can quickly know the previous process of this conference. Part or all of the data in the virtual meeting room can be cleared by some or all users selected in the virtual meeting room.

In a multimedia conference between workstations (12, 14), the conference room server (48) is connected to one of the data servers (50) on the network (10) through a two-way connection (52). The conference room server (48) is connected to one of the image servers (54) on the network (10) through a two-way connection (56). Similarly, the conference room server (48) is connected to one of the voice servers (58) on the network (10) through a two-way connection (60). The conference room server (48) is connected to one of the name servers (62) on the network (10) through a two-way connection (60).

The data server respectively receives the data output and data signal generated by the data manager (30, 40) on the workstation (12, 14) via the two-way connection (66, 68). The data output and data signals from each workstation (12, 14) are directed from the data server (50) to the data server of other workstations, so that the data generated by each workstation can be shared by users of the two workstations (12, 14) . This task is performed by the data server (50) receiving the data output and signals of the data manager (30) of the workstation (12) via the line (66) and directing it to the data manager (14) of the workstation (14) via the line (68) 40) Come to achieve. The data server (50) can also receive the data output and signal from the data manager (40) of the workstation (14) via the line (68), and direct the data output and signal to the data of the workstation (12) via the line (66) The input of the manager (30).

The image server (54) receives the image output and image signals from the workstation (12) of the image manager (32) via the dual connection (70), and receives the workstation from the image manager (42) via the dual connection (72) Video output and video signal. The image server (54) directs the images and signals received from the workstation (12) on the connection (70) to the workstation (14) via the connection (72). The image server (54) also directs the images and signals received from the workstation (14) on the connection (72) to the workstation (12) via the connection (70).

The voice server (58) receives the voice output and voice signals from the workstation (12) of the voice server (34) by the dual connection (74), and directs those voice output signals to the workstation (14) via the dual connection (76) ) In the voice manager (44). This voice server (58) also receives voice output and voice signals from the workstation (14) of the voice manager (44) by the connection (76), and directs those voice outputs and signals to the voice manager (34) by the connection (74) ).

Although the example of the present invention shown in FIG. 2 only deals with the connection between two multimedia workstations, the present invention is equally applicable to any number of participants. The data server (50), image server (54), and voice server (58) essentially act as a bridge circuit to connect the media output of individual participants and direct those selected outputs to the participants via appropriate communication paths By. The combination and reconciliation of the server used to form an effective media conference among many participants is controlled by the multimedia server (48), which uses the information stored in the virtual meeting room to control the conference between the participants Meeting. A meeting room interface (78) is connected to the meeting room server (48), so the server (48) must be provided with information generated by the network manager (or other similar ones). Information about meeting rooms in the network (10) can be obtained from the interface (78). The conference room server is connected to other conference room servers on the network (10) through the connection of the input/output ports of the server (48). This server (48) is used when participants use different conference rooms on the network. is needed.

Figure 4 is a state diagram showing in detail the actual operation of the conference room server in Figure 1. The same operation map can be applied to every virtual meeting room controlled by the server (48). In Fig. 4, with respect to a given virtual meeting room, each state owned by the server (48) is graphically represented in a flat ellipse structure. The transition between states is represented by an arrow marked with "E" plus a number. The self-loop is distinguished by "SL" plus a number. Table I lists all the state transitions in Figure 4. Table I lists the complete list of allowable transitions, called "edges", including the identification of the result of triggering the transition between the two states.

Before the server (48) opens a virtual meeting room, the server is in the local state (82). The server (48) receives a command from the session manager associated with the server (48) in the workstation to open an empty virtual meeting room. This meeting room is a configuration of memory space or other computer resources and becomes the open virtual meeting room The user and other users will enter the conference. The conference room server leaves the state (82) and enters the empty room state (84). Under the pre-determined media, an appropriate server is connected to this empty room to form an effective meeting. These servers are selected from the collection of servers on the network, as shown in Figure 1. When the server is connected to the virtual meeting room, the meeting room server (48) leaves the empty room state (84) and enters a waiting state (86). At this moment, the requested server has indeed been set to the virtual meeting room. For example, when a server that is requested to connect to the virtual meeting room is approved, the meeting room server enters the state (88), which indicates that there is at least one virtual meeting room Connect to a server. When the server (48) is in the state (88), additional servers can be added to the virtual meeting room under appropriate instructions from the session manager, as shown in the second waiting state (90) in FIG. 4.

In addition to opening an empty virtual meeting room and connecting pre-set network resources with the virtual meeting room, the actual meeting can be held in the virtual meeting room, so the participants are connected with other participants under the selected media. Two or more participants can share one or more voices, such as normal voice conversations, data, such as computer programs, and images, such as images captured by cameras that fall on the participants. At this point, the session manager sends a signal to the conference server to start a conference in the virtual meeting room. The server (48) leaves the state (88) and enters the state (90). In this state (90), the virtual meeting room contains the server and the meeting is being hosted. In the state (90), additional servers can be added, as shown in the state (92) in FIG. 4. When the server is in the state (90), any number of participants can enter or leave the conference, as shown in Figure 4 from the loop SL2. A conference can be suspended midway, regardless of whether all participants are in the conference or all of them leave the network (10), as shown in Figure 4, the transition from state (90) to state (94). Because the virtual meeting room has reserved features, the meeting room and its information are continuously stored in the network (10), which meets the needs of meeting room users. One or more users can resume the conference where the conference was suspended, such as the transition from state (94) to state (90).

In addition to the above-mentioned states and transitions, the meeting room server (48) can also enter the state (96) from the empty room state (84). In this empty room state (84), there is a virtual meeting room where there is a meeting without a server In the server (48). The server can be added as a representation of the waiting state (98), from which the state (98) can enter the state (90) to include a virtual meeting room connected to the server and the participants. Under the instruction of the session manager, the conference room server (48) can enter the terminal state (100) from any state in Figure 4, and in the terminal state, the virtual conference room and its contents will be completely uploaded from the network (10) eliminate.

Figure 5 is a state diagram showing the operation of a single virtual meeting room by a session manager on a multimedia network. The additional state diagram also shows the operations of the session manager on other virtual meeting rooms connected to the manager as shown in FIG. 5. Like Figure 4, the state diagram in Figure 5 is composed of state representations, and the session manager stays in each state along with the transition between states. Table II lists all allowed transitions, called "edges", including the identification of the result of triggering the transition between two states.

For the purpose of this statement, we assume that a user of one workstation (12) calls another workstation (14) to use. Before the workstation user issues an instruction to open the virtual meeting room on the network (10), the operation of the session manager starts from the local state (102). When the user of the workstation (12) wants to communicate with other people (for example, the user of the workstation (14)), he enters a user interface requesting to enter the workstation (12). This is the same as dialing the other party's conversation number as the initial setting for phone contact between the two parties when making a call. Users who want to connect to another workstation can select the media to be used for the meeting from the menu. Alternatively, the information that the media will be used is also stored between the two workstation users to automatically form an appropriate connection between the users. Once the initial user of the workstation (12) has specified another user that he wants to set up a connection, the session manager (28) enters the waiting state (104), during the state (104), the session manager (28) waits for the meeting The room server (48) opens an appropriate virtual meeting room on the network (10). When the session manager (28) notices that the virtual meeting room has been established, the session manager (29) enters the waiting state (106). At this time, the session manager waits for a meeting room server to complete the connection to the appropriate media server Instructions for the virtual meeting room. Regardless of whether the server is added to the virtual meeting room or not, the meeting room server (28) will organize the local resources on the workstation (12) to the appropriate interface of each server connected to the virtual meeting room. When all appropriate servers are connected to the virtual meeting room, the session manager enters the state (108). When the session manager is in the state (108), a transition from state (108) to state (112) and back again occurs, and additional servers can be added to the conference room. In the same way, there is a transition from state (108) to state (110) and then back, and the server can be removed from the conference room. Whenever the server is removed from the conference room, the session manager will also remove the corresponding partial resources from the conference.

When the session manager (28) is in the state (108), a meeting can be started in the virtual meeting room. When the session manager waits to start a meeting, the session manager (28) transitions from the state (108) to the state (114). Alternatively, the session manager can also reach the state (114) via the state (150), and the state (150) does not include the connection between the server and the conference room. When the session manager reaches the conference progress state (122), the server can also be added to the virtual meeting room opened via the state (150). This state (112) is similar to the aforementioned state (104).

To start a meeting in a virtual meeting room is to open some identifications for the meeting in the meeting room. After the meeting is opened in the virtual meeting room, the session manager (28) changes from the state (114) to the state (116). During the state (116), the session manager (28) asks the meeting room server for information about the workstation Information about the object the user wants to contact (for example, the location of the other party). After obtaining these messages, the session manager (28) changes from the state (116) to the state (118). During the state (118), it waits for information to be sent to and returned from the object to be contacted. When the received return message is that the called group is willing to have a meeting with the calling group, the session manager (28) will send a message to the conference room server (48), adding a called groups identity to the virtual meeting room. The session manager is in state (120) awaiting approval of this practice. After receiving the approval, the session manager changes from the state (120) to the conference proceeding state (112). During this state (120), the users of the two workstations communicate and communicate with the other party through the selected media.

The above statement is under the condition that the user of the workstation (12) first sets the connection with the user of the workstation (14). In the exchange situation, the user of the workstation (14) first sets up the connection with the user of the workstation (12), and the session manager changes from the state (102) to the state (124). In this state (124), the workstation (12) The user invites the user of the workstation (14) to participate in a multimedia conference. The session manager (28) waits for the user of the workstation (12) to accept the invitation in the state (124). When the user of the workstation (12) accepts the invitation, the session manager changes from the state (124) to the state (126). In this state (126), it waits for the workstation (12) to join the conference for approval. After that, the session The manager transitions from state (126) to state (122).

When the conference is in progress and the session manager is in the state (122), new participants can join the conference through the transition between the states (122, 123, 130, and 132) in FIG. 5. Participants can also exit the conference via the transition between the states (122, 13) in Figure 5. The server can be added via the transition between the states (122, 136) in Figure 5. The server can also exit through a transition between states (122, 138).

Any participant can put himself in the reservation and leave the meeting temporarily, and the session manager of the reservation enters the state (140). When the participant wants to return to the conference in the reserved place, the session manager (28) changes from the state (140) to the state (142), and if permission is obtained to return to the conference, the session manager (28) transitions to the state (122).

One or more participants (such as users of the workstation (12)) may all be placed on hold or even leave the network and the conference will be suspended. In any case, part or all of the virtual meeting room remains on the network, so the meeting can be resumed from where it was suspended. In addition, the storage function of the media server described below can allow those who return to the meeting after a pause to read part or all of the meeting process. When the meeting is suspended, the session manager (28) transitions from the state (122) to the state (144), and then to the state (146). When the conference is resumed, the session manager (28) transitions from the state (146) to the state (148), and then back to the state (122).

When the session manager (28) is in the local state (102), a user of the workstation (12) may also search and want to join the ongoing conference. The user will indicate the meeting he wants to join, and the session manager will change from the state (102) to the state (154). In fact, the Internet is questionable regarding participants sending invitations to users to join a meeting and joining an existing meeting. When this instruction occurs, the session manager (28) will transition from the state (154) to the state (124) and the operation of the session manager will continue as described above. In the case where the user of the workstation (12) has become a participant in an ongoing conference and the session manager (28) is in the state (122), a request from a non-participant from another workstation will cause the session manager ( 28) Transition from state (122) to state (156). If the user of the workstation (12) sends an invitation to the new entrant, the session manager (28) will change from the state (156) to the state (122).

As shown in Fig. 5, the session manager (28) can enter the terminal state (158) from any selected state (shown in Fig. 5). The terminal state (158) can be considered equivalent to the ground state (102).

FIG. 6 is a schematic diagram of the media server shown in FIG. 1. FIG. All media servers use this structure. The media server contains a media bridge (160), which is used to receive individual media output from each participant. The media bridge (160) combines the selected media output from the participant and points this combination back to the selected participant. The controller (162) controls the combination of the participant's output and the direction of these outputs back to the participant. In the case of a voice server, the media bridge can be any teleconference connection, which receives the voice output of each participant and can controllably direct the selected voice output to each participant. In the case of a data server, the media bridge can be any data bridge (such as a window bridge or an X window bridge), which receives the data output of the participants and directs the selected data output to each user. Similarly, in the case of a video server, any video bridge can be used as a media bridge (160) to receive video output from participants and direct the selected video output to each participant. The media bridge (160) can be connected to a storage device on the network, and this network can store information about different aspects of the virtual conference room meeting. For example, the storage device (164) can store video information related to the conference (such as video recording of the conference), and the media bridge at this time is a video bridge. It can also store information about computer programs for participants to use, for example, the status of executable programs. At this time, the media bridge is a data bridge. When the media bridge is a voice bridge, it can also store some or all of the recordings of the participants. The media bridge (160) can also be connected to a similar storage device (166) outside the network (10).

Appendix 1 is an example agreement on multimedia networks. Appendices 2 and 3 are computer codes, which represent the implementation examples of the aforementioned meeting room server and session manager. This program is written in the well-known C++ programming language. This program can run on UNIX^®Compile and execute on the workstation of S-un Microsystem of the operating system. The copyright patents of these computer programs are owned by American Telephone &amp; Telegraph Co., except for the reproduction of this patent document, copying of this program is prohibited.

<img file="TW239248B_D0002.tif" />

<img file="TW239248B_D0003.tif" />

<img file="TW239248B_D0004.tif" />

<img file="TW239248B_D0005.tif" />

<img file="TW239248B_D0006.tif" />

<img file="TW239248B_D0007.tif" />

<img file="TW239248B_D0008.tif" />

<img file="TW239248B_D0009.tif" />

<img file="TW239248B_D0010.tif" />

<img file="TW239248B_D0011.tif" />

<img file="TW239248B_D0012.tif" />

<img file="TW239248B_D0013.tif" />

<img file="TW239248B_D0014.tif" />

<img file="TW239248B_D0015.tif" />

<img file="TW239248B_D0016.tif" />

<img file="TW239248B_D0017.tif" />

<img file="TW239248B_D0018.tif" />

<img file="TW239248B_D0019.tif" />

<img file="TW239248B_D0020.tif" />

<img file="TW239248B_D0021.tif" />

<img file="TW239248B_D0022.tif" />

<img file="TW239248B_D0023.tif" />

<img file="TW239248B_D0024.tif" />

<img file="TW239248B_D0025.tif" />

<img file="TW239248B_D0026.tif" />

<img file="TW239248B_D0027.tif" />

<img file="TW239248B_D0028.tif" />

<img file="TW239248B_D0029.tif" />

<img file="TW239248B_D0030.tif" />

<img file="TW239248B_D0031.tif" />

<img file="TW239248B_D0032.tif" />

<img file="TW239248B_D0033.tif" />

<img file="TW239248B_D0034.tif" />

<img file="TW239248B_D0035.tif" />

<img file="TW239248B_D0036.tif" />

<img file="TW239248B_D0037.tif" />

<img file="TW239248B_D0038.tif" />

<img file="TW239248B_D0039.tif" />

<img file="TW239248B_D0040.tif" />

<img file="TW239248B_D0041.tif" />

<img file="TW239248B_D0042.tif" />

<img file="TW239248B_D0043.tif" />

<img file="TW239248B_D0044.tif" />

<img file="TW239248B_D0045.tif" />

<img file="TW239248B_D0046.tif" />

<img file="TW239248B_D0047.tif" />

<img file="TW239248B_D0048.tif" />

<img file="TW239248B_D0049.tif" />

<img file="TW239248B_D0050.tif" />

<img file="TW239248B_D0051.tif" />

<img file="TW239248B_D0052.tif" />

<img file="TW239248B_D0053.tif" />

<img file="TW239248B_D0054.tif" />

<img file="TW239248B_D0055.tif" />

<img file="TW239248B_D0056.tif" />

<img file="TW239248B_D0057.tif" />

<img file="TW239248B_D0058.tif" />

<img file="TW239248B_D0059.tif" />

<img file="TW239248B_D0060.tif" />

<img file="TW239248B_D0061.tif" />

<img file="TW239248B_D0062.tif" />

<img file="TW239248B_D0063.tif" />

<img file="TW239248B_D0064.tif" />

<img file="TW239248B_D0065.tif" />

<img file="TW239248B_D0066.tif" />

<img file="TW239248B_D0067.tif" />

<img file="TW239248B_D0068.tif" />

<img file="TW239248B_D0069.tif" />

<img file="TW239248B_D0070.tif" />

<img file="TW239248B_D0071.tif" />

<img file="TW239248B_D0072.tif" />

<img file="TW239248B_D0073.tif" />

<img file="TW239248B_D0074.tif" />

<img file="TW239248B_D0075.tif" />

<img file="TW239248B_D0076.tif" />

<img file="TW239248B_D0077.tif" />

<img file="TW239248B_D0078.tif" />

<img file="TW239248B_D0079.tif" />

<img file="TW239248B_D0080.tif" />

<img file="TW239248B_D0081.tif" />

<img file="TW239248B_D0082.tif" />

<img file="TW239248B_D0083.tif" />

<img file="TW239248B_D0084.tif" />

<img file="TW239248B_D0085.tif" />

<img file="TW239248B_D0086.tif" />

<img file="TW239248B_D0087.tif" />

<img file="TW239248B_D0088.tif" />

<img file="TW239248B_D0089.tif" />

<img file="TW239248B_D0090.tif" />

<img file="TW239248B_D0091.tif" />

<img file="TW239248B_D0092.tif" />

<img file="TW239248B_D0093.tif" />

<img file="TW239248B_D0094.tif" />

<img file="TW239248B_D0095.tif" />

<img file="TW239248B_D0096.tif" />

<img file="TW239248B_D0097.tif" />

<img file="TW239248B_D0098.tif" />

<img file="TW239248B_D0099.tif" />

<img file="TW239248B_D0100.tif" />

<img file="TW239248B_D0101.tif" />

<img file="TW239248B_D0102.tif" />

<img file="TW239248B_D0103.tif" />

<img file="TW239248B_D0104.tif" />

<img file="TW239248B_D0105.tif" />

<img file="TW239248B_D0106.tif" />

<img file="TW239248B_D0107.tif" />

<img file="TW239248B_D0108.tif" />

<img file="TW239248B_D0109.tif" />

<img file="TW239248B_D0110.tif" />

<img file="TW239248B_D0111.tif" />

<img file="TW239248B_D0112.tif" />

<img file="TW239248B_D0113.tif" />

<img file="TW239248B_D0114.tif" />

<img file="TW239248B_D0115.tif" />

<img file="TW239248B_D0116.tif" />

<img file="TW239248B_D0117.tif" />

<img file="TW239248B_D0118.tif" />

<img file="TW239248B_D0119.tif" />

<img file="TW239248B_D0120.tif" />

<img file="TW239248B_D0121.tif" />

<img file="TW239248B_D0122.tif" />

<img file="TW239248B_D0123.tif" />

<img file="TW239248B_D0124.tif" />

<img file="TW239248B_D0125.tif" />

<img file="TW239248B_D0126.tif" />

<img file="TW239248B_D0127.tif" />

<img file="TW239248B_D0128.tif" />

<img file="TW239248B_D0129.tif" />

<img file="TW239248B_D0130.tif" />

<img file="TW239248B_D0131.tif" />

<img file="TW239248B_D0132.tif" />

<img file="TW239248B_D0133.tif" />

<img file="TW239248B_D0134.tif" />

<img file="TW239248B_D0135.tif" />

<img file="TW239248B_D0136.tif" />

<img file="TW239248B_D0137.tif" />

<img file="TW239248B_D0138.tif" />

<img file="TW239248B_D0139.tif" />

<img file="TW239248B_D0140.tif" />

<img file="TW239248B_D0141.tif" />

<img file="TW239248B_D0142.tif" />

<img file="TW239248B_D0143.tif" />

<img file="TW239248B_D0144.tif" />

<img file="TW239248B_D0145.tif" />

<img file="TW239248B_D0146.tif" />

<img file="TW239248B_D0147.tif" />

<img file="TW239248B_D0148.tif" />

<img file="TW239248B_D0149.tif" />

<img file="TW239248B_D0150.tif" />

<img file="TW239248B_D0151.tif" />

<img file="TW239248B_D0152.tif" />

<img file="TW239248B_D0153.tif" />

<img file="TW239248B_D0154.tif" />

<img file="TW239248B_D0155.tif" />

<img file="TW239248B_D0156.tif" />

<img file="TW239248B_D0157.tif" />

<img file="TW239248B_D0158.tif" />

<img file="TW239248B_D0159.tif" />

<img file="TW239248B_D0160.tif" />

<img file="TW239248B_D0161.tif" />

<img file="TW239248B_D0162.tif" />

<img file="TW239248B_D0163.tif" />

<img file="TW239248B_D0164.tif" />

<img file="TW239248B_D0165.tif" />

<img file="TW239248B_D0166.tif" />

<img file="TW239248B_D0167.tif" />

<img file="TW239248B_D0168.tif" />

<img file="TW239248B_D0169.tif" />

<img file="TW239248B_D0170.tif" />

<img file="TW239248B_D0171.tif" />

<img file="TW239248B_D0172.tif" />

<img file="TW239248B_D0173.tif" />

<img file="TW239248B_D0174.tif" />

<img file="TW239248B_D0175.tif" />

<img file="TW239248B_D0176.tif" />

<img file="TW239248B_D0177.tif" />

<img file="TW239248B_D0178.tif" />

<img file="TW239248B_D0179.tif" />

<img file="TW239248B_D0180.tif" />

<img file="TW239248B_D0181.tif" />

<img file="TW239248B_D0182.tif" />

<img file="TW239248B_D0183.tif" />

<img file="TW239248B_D0184.tif" />

<img file="TW239248B_D0185.tif" />

<img file="TW239248B_D0186.tif" />

<img file="TW239248B_D0187.tif" />

<img file="TW239248B_D0188.tif" />

<img file="TW239248B_D0189.tif" />

<img file="TW239248B_D0190.tif" />

<img file="TW239248B_D0191.tif" />

<img file="TW239248B_D0192.tif" />

<img file="TW239248B_D0193.tif" />

<img file="TW239248B_D0194.tif" />

<img file="TW239248B_D0195.tif" />

<img file="TW239248B_D0196.tif" />

<img file="TW239248B_D0197.tif" />

<img file="TW239248B_D0198.tif" />

<img file="TW239248B_D0199.tif" />

<img file="TW239248B_D0200.tif" />

<img file="TW239248B_D0201.tif" />

<img file="TW239248B_D0202.tif" />

<img file="TW239248B_D0203.tif" />

<img file="TW239248B_D0204.tif" />

<img file="TW239248B_D0205.tif" />

<img file="TW239248B_D0206.tif" />

<img file="TW239248B_D0207.tif" />

<img file="TW239248B_D0208.tif" />

<img file="TW239248B_D0209.tif" />

<img file="TW239248B_D0210.tif" />

<img file="TW239248B_D0211.tif" />

<img file="TW239248B_D0212.tif" />

<img file="TW239248B_D0213.tif" />

<img file="TW239248B_D0214.tif" />

<img file="TW239248B_D0215.tif" />

<img file="TW239248B_D0216.tif" />

<img file="TW239248B_D0217.tif" />

<img file="TW239248B_D0218.tif" />

<img file="TW239248B_D0219.tif" />

<img file="TW239248B_D0220.tif" />

<img file="TW239248B_D0221.tif" />

<img file="TW239248B_D0222.tif" />

<img file="TW239248B_D0223.tif" />

<img file="TW239248B_D0224.tif" />

<img file="TW239248B_D0225.tif" />

<img file="TW239248B_D0226.tif" />

<img file="TW239248B_D0227.tif" />

<img file="TW239248B_D0228.tif" />

<img file="TW239248B_D0229.tif" />

<img file="TW239248B_D0230.tif" />

<img file="TW239248B_D0231.tif" />

<img file="TW239248B_D0232.tif" />

<img file="TW239248B_D0233.tif" />

<img file="TW239248B_D0234.tif" />

<img file="TW239248B_D0235.tif" />

<img file="TW239248B_D0236.tif" />

<img file="TW239248B_D0237.tif" />

<img file="TW239248B_D0238.tif" />

<img file="TW239248B_D0239.tif" />

<img file="TW239248B_D0240.tif" />

<img file="TW239248B_D0241.tif" />

<img file="TW239248B_D0242.tif" />

<img file="TW239248B_D0243.tif" />

<img file="TW239248B_D0244.tif" />

<img file="TW239248B_D0245.tif" />

<img file="TW239248B_D0246.tif" />

<img file="TW239248B_D0247.tif" />

<img file="TW239248B_D0248.tif" />

<img file="TW239248B_D0249.tif" />

<img file="TW239248B_D0250.tif" />

<img file="TW239248B_D0251.tif" />

<img file="TW239248B_D0252.tif" />

<img file="TW239248B_D0253.tif" />

<img file="TW239248B_D0254.tif" />

<img file="TW239248B_D0255.tif" />

<img file="TW239248B_D0256.tif" />

<img file="TW239248B_D0257.tif" />

<img file="TW239248B_D0258.tif" />

<img file="TW239248B_D0259.tif" />

<img file="TW239248B_D0260.tif" />

<img file="TW239248B_D0261.tif" />

<img file="TW239248B_D0262.tif" />

<img file="TW239248B_D0263.tif" />

<img file="TW239248B_D0264.tif" />

<img file="TW239248B_D0265.tif" />

<img file="TW239248B_D0266.tif" />

<img file="TW239248B_D0267.tif" />

<img file="TW239248B_D0268.tif" />

<img file="TW239248B_D0269.tif" />

<img file="TW239248B_D0270.tif" />

<img file="TW239248B_D0271.tif" />

<img file="TW239248B_D0272.tif" />

<img file="TW239248B_D0273.tif" />

<img file="TW239248B_D0274.tif" />

<img file="TW239248B_D0275.tif" />

<img file="TW239248B_D0276.tif" />

<img file="TW239248B_D0277.tif" />

<img file="TW239248B_D0278.tif" />

<img file="TW239248B_D0279.tif" />

<img file="TW239248B_D0280.tif" />

<img file="TW239248B_D0281.tif" />

<img file="TW239248B_D0282.tif" />

<img file="TW239248B_D0283.tif" />