Abstract:
A video teleconferencing system and method for providing reservationless conferencing is disclosed. The method involves creating a conference profile identifying selected connection parameters; allocating a dial-in number; notifying participants of the dial-in number; detecting a call from a requesting participant; determining if sufficient resources for the participant are available; and connecting the requesting participant into the reservationless conference. Additionally, the video teleconferencing method allows the conference time to be automatically extended. This is done using timers and reallocating available resources when the original end of conference time arrives. The method also enables the conference to automatically terminate after all conference participants leave the conference.

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 10/954,934, filed Sep. 30, 2004, now U.S. Pat. No. 7,310,320, which is a divisional application of U.S. patent application Ser. No. 09/790,577, filed Feb. 22, 2001, now U.S. Pat. No. 7,085,243, which claims priority to provisional application No. 60/186,002, filed Mar. 1, 2000. Each of U.S. patent application Ser. No. 10/954,934, U.S. patent application Ser. No. 09/790,577, U.S. Pat. No. 7,085,243, and provisional application No. 60/186,002 are incorporated herein by reference in their entirety and priority to each of these applications is hereby claimed. 
    
    
     TECHNICAL FIELD 
     This invention relates to the field of audio and video conferencing and, more particularly, relates to automating the process of coordinating and setting up audio and video conferences. 
     BACKGROUND 
     Traditionally, customers wishing to use a multi-point video conferencing service must reserve their conferences in advance. The customer must provide several parameters to complete such a reservation, including the number and types of terminals, line-speed, type of audio algorithm, start-time, end-time, video algorithm, type of network, along with other pertinent parameters. Providing these parameters presents a problem to both conference participants and service providers due to the fact that acquiring this information is difficult and providing this information makes the process of setting up or initiating a conference tedious and inconvenient. In addition, the customer must provide this information well in advance of the actual conference to reserve time and resources, and to allow adequate time to process the information and incorporate it into the conference setup. 
     Companies that provide video conferencing services typically use reservation-based systems to manage the service. Using such a service, a client contacts the service provider prior to the start of the conference to book or reserve the conference and any necessary facilities or resources. When making the reservation, the customer must provide the service operator with parameters, such as the number and types of terminals, line-speed, type of audio algorithm, start-time, end-time and other parameters. In response, the service operator must input these parameters into the reservations system. 
       FIG. 1  is a block diagram illustrating a typical system architecture of an audio/video conferencing system. Using a system as illustrated in  FIG. 1 , a service provider sets up an audio and/or video conference for a customer by completing the following tasks: 
     (1) A customer administrator  120  contacts, using a telephone, facsimile, e-mail or other means  2  a service provider operator  112 . 
     (2) The service provider operator  112  receives conference parameters from the customer administrator  120  and loads them into the reservation system via an operator console  116 . 
     (3) The service provider operator  112  notifies the customer administrator  120  with a confirmation of the reserved conference details (for example: the ISDN number(s) that will be used to connect to the conference). 
     (4) The customer administrator  120  provides the details of the conference, such as start-time and the number to call, to the participants or terminals  114  that will participate in the conference. 
     (5) The video conference is started on the service provider&#39;s MCU  110  at the reserved time and lasts for the pre-defined duration. During this time the conference terminals  114  can be connected to the conference. 
     (6) When the duration set for the conference is over, the conference is terminated and the terminals  114  are disconnected. 
     For each customer that attempts to set up a conference call, each step in the process must be repeated. 
     These prior art techniques for reserving and initiating conferences are disadvantageous for several reasons. One reason is that the prior art techniques require a cumbersome reservation procedure. Also, if the actual duration of the conference is longer than the reserved time, the conference may terminate in the middle of a discussion. If the actual duration of the conference is shorter than the reserved time, the customer will end up paying for the unused time. Thus, there is a need in the art for a system and method to schedule and reserve audio and/or video conferences that allows more flexibility in the length of the conference. 
     Another disadvantage in the prior art techniques is that they do not allow any flexibility in the start-time of the conference and/or the number of participants in the conference. In today&#39;s complex world, conferences are often times canceled at the last minute. Using the reservation techniques in the prior art, this lack of flexibility can be quite costly. Thus, there is a need in the art for a system and method to schedule and reserve audio and/or video conferences that allows more flexibility in the start time of the conference and the number of participants. 
     Yet another disadvantage of the prior art techniques is that they require extensive overhead to set up a conference. For instance, an operator is required on the service provider side and a conference administrator is required on the customer side. This overhead escalates the cost associated with providing audio and/or video conferencing services. Thus, there is a need in the art for a system and a method to schedule and reserve audio and/or video conferences that limits the amount of required overhead. 
     Therefore, it is clear that there is a need in the art for a system and a method for providing reservationless audio and/or video conferences. 
     SUMMARY 
     The present invention solves the above-described problems by providing a system and method for providing reservationless conferences. In general, the present invention removes the need for reservations. Instead, customers are able to initiate their own conferences at their convenience, without the need for pre-booking or operator intervention. 
     The present invention advantageously limits or eliminates the need for a human operator. Using the present invention, a moderator can initiate the conference without contacting an operator. Instead, the moderator simply initiates the conference by dialing a dial-in conference number. In addition, the present invention eliminates the need to identify the conference start-time, the conference duration and the number of needed resources, such as the number of participants, prior to reserving the conference. Another aspect of the present invention is an auto rate detector. The auto rate detector enables the connection of terminals to a conference without any prior knowledge about the terminal capabilities, such as the type of terminal, the terminal bit rate, or the like. Advantageously, this aspect of the present invention reduces overhead required in setting up a conference. Yet another aspect of the present invention is an auto termination and auto extend feature. The auto termination feature advantageously allows a conference to be disconnected without requiring user intervention. The auto extension feature of the present invention advantageously allows conferences in indefinite duration to be reserved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating a typical system architecture of an audio and/or video conferencing system of the present invention. 
         FIG. 2  is a flow diagram illustrating the steps performed in an exemplary embodiment of creating a reservationless conference. 
         FIG. 3  is a block diagram illustrating an exemplary embodiment of the present invention. 
         FIG. 4  is a flow diagram illustrating the operation of performing the auto terminate aspect of the present invention. 
         FIG. 5  is a flow diagram illustrating the auto extension aspect of the present invention. 
         FIG. 6  is a screen image of an exemplary embodiment of a user interface showing conference profile settings. 
     
    
    
     DETAILED DESCRIPTION 
     Turning now to the figures in which like numeral represent like elements throughout the several views, several exemplary embodiments of the present invention are described. 
     A first exemplary embodiment of the present invention is a limited operator system. In this embodiment, the system assigns a dial-in number to a customer, a dial-in number can be a telephone number, an IP address or the like. The customer, and conference co-participants, use this dial-in number whenever they want to have a conference. When a participant uses his or her terminal to dial this number, the system will automatically initiate the conference. In addition, for each terminal that dials this number, the system will automatically connect the terminal into the conference. When all participants disconnect, the conference is terminated. Using this embodiment of the present invention, the participants can initiate the conference at anytime by simply by dialing the conference number. Thus, this embodiment of the present invention only requires a one-time contact with an operator in order to acquire the dial-in number. This one-time can be performed at anytime without connection to a certain conference. 
       FIG. 1 . is a block diagram illustrating a typical system architecture of an audio and/or video conferencing system. The limited operator exemplary embodiment of the reservationless system of the present invention is similar to that in  FIG. 1 , with the crucial difference that after the dial-in number has been assigned, the operator  112  is no longer required. The limited operator embodiment includes a multi-point control unit (“MCU”)  110  and an operator console  116 . The MCU is a conference controlling entity that typically is a piece of equipment located in a node of the network or in a terminal which receives several channels from access ports and, according to certain criteria, processes audiovisual signals and distributes them to the connected channels. Examples of MCU&#39;s include the MGC-100 which is available from Polycom, Inc., the assignee of the present invention. Additional information about the MGC-100 can be found at the website of www.polycom.com. The MCU  110  and the operator console  116  are typically located at a service provider site, although this is not mandatory. Each participant in a conference utilizes a terminal  114 . A terminal is an endpoint on a network, capable of providing real-time, two-way audio and/or visual communication with other terminals or an MCU. The information communicated between the terminals and/or the MCU includes control signals, indicators, audio, moving color video pictures and/or data. A terminal may provide speech only, speech and data, speech and video, or speech, data and video. A more thorough definition of a terminal can be found in the International Telecommunication Union (“ITU”) standards H.320, H.321 and H.323. The ITU is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing recommendations on them with a view to standardizing telecommunications on a worldwide basis. Additional information regarding the ITU can be found at the website address of www.itu.int. 
     The customer administrator  120  can exert control over each of the terminals  114  through an administrator/terminal interface  108 . Each terminal  114  interfaces to the MCU  110  over a conference interface  106 . The MCU  110  includes a memory storage element  118  and communicates with the operator console  116  over the operator console to MCU interface  104 . Optionally, the MCU  110  may interface to an optional server  122  having an additional storage element  124 . 
       FIG. 2  is a flow diagram illustrating the steps involved in an exemplary embodiment of creating a reservationless conference. The customer initiating or organizing the conference is referred to as a moderator. Initially, the moderator creates a conference profile  270 . To accomplish this, the moderator communicates with the operator and defines the parameters of the conference, such as the maximum bit-rate, whether or not transcoding is to be used, the video layout, or similar information. The moderator is not required to provide the conference start-time, duration, or the number of participants in the conference. Once the operator enters the conference profile into the system, a conference profile form is sent via the operator console  116  to the MCU  110  over an operator console to an MCU interface  104 . 
     Next a dial-in number is allocated for the conference  272 . Upon receiving the conference profile form, the MCU  110  assigns a dial-in number for the conference. The MCU  110  is configured to have a range of dial-in numbers, and the dial-in numbers are allocated to conference profiles using an assignment algorithm. The assignment algorithm can be in a variety of forms and the present invention is not limited to any particular algorithm. In an exemplary embodiment, the assignment algorithm may be a first come first served algorithm. As an example of using the first come first served algorithm, if the range of numbers held by the MCU  110  is 1000 to 5000, then the first conference profile will get the number 1000, the second will get 1001, etc. After assigning a dial-in number, the MCU  110  notifies the operator  112  that the dial-in number has been assigned. The MCU  110  provides this notice through the operator console  116  via the operator console to the MCU interface  114 . 
     After receiving the dial-in number from the operator console  116 , the operator  112  notifies the moderator or any participant in the conference of the conference dial-in number  274 . The moderator distributes the conference dial-in number  276  to the other participants of the conference using a variety of techniques including, but not limited to, placing a telephone call, or sending notice in the mail, e-mail, or facsimile. 
     Once a conference profile has been created, the moderator can delete the conference profile at any time by contacting the operator  112  to delete the conference. The operator  112 , upon receiving such notice, will delete the conference profile via the operator console  116 . After deleting a conference profile, or in conjunction therewith, the operator console  116  notifies the MCU  110 . In response to receiving such notice, the MCU  110  removes the conference profile record from its internal storage  118 , allowing for the dial-in number to be reallocated to new conference profiles. In an alternate embodiment, the moderator may be given access to the operator console to delete the profile without the interaction with the operator  112 . 
     When the moderator, or any participant, wishes to start the conference  278 , he/she dials the dial-in number from a terminal  114 . Upon receiving the call, the MCU  110  searches for a conference profile match. A conference profile match is found if a conference profile has the same dial-in number that was called. To identify a match, the MCU  110  searches its internal storage  118  for a conference profile match. If such a match is found, the MCU  110  starts the conference immediately. The start-time of the conference is the current time and the conference will last for a pre-defined time duration T. The value of T is part of the MCU  110  conference profile. 
     If a conference profile match is not found, the MCU  110  may optionally connect to an external or optional server  122 . The optional server  122  includes a processing unit with a storage device  124  connected to the MCU  110  via a network connection or some other communication path  126 . The MCU  110  provides the dial-in number to the optional server  122 . The optional server  122  searches its internal storage  124  for a conference profile with the same dial-in number. If such a conference profile is found, the optional server  122  orders the MCU  110  to start the conference immediately. Again, the start-time of the conference is the current time, and the duration of the conference is a pre-defined time duration T as previously defined. 
     If a match is not found, the MCU  110  may reject the call, display an audiovisual message to the calling terminal and/or transfer the call to a service provider operator. The remaining steps of this embodiment of the invention are described below following a description of an alternate embodiment of the present invention. The following steps,  279  to  288 , are described after the description of  FIG. 3 . 
       FIG. 3  is a block diagram illustrating a second exemplary embodiment of the present invention. The second exemplary embodiment of the present invention is an operator independent system. In this embodiment of the present invention, the need for the operator is totally eliminated. The reservationless system in this embodiment includes, but is not limited to, an MCU  110 , a web server  346 , and a web browser  340 . One possible configuration for the web server  346  is a Microsoft NT server running IIS4. The web browser  340  may include a variety of commercially available browsers, such as the Microsoft Internet Explorer, or a proprietary browser. The web browser  340  connects to an intranet or Internet  348  over a first connection  352 . The web server  346  is connected to the intranet or Internet  348  over a second connection  354 . Thus, the web browser  340  can connect to the web server  346  via the intranet or Internet  348 . 
     The web browser can actually be any communication program that can interface to the web server over a networked connection. Thus, the present invention is not limited to a web browser, or any particular web browser. In general, the functions of the web browser can be performed by a variety of communication programs including terminal emulators, FTP programs, SMTP programs or the like. 
     The MCU  110  and the web server  346  are typically located at the service provider site; however, this is not mandatory. Typically, the MCU  110  and the web server  346  communicate over a network communication connection  356 . The network communication connection  356  may be an intranet, the Internet, a local area network, or any other communication connection capable of interfacing the web server  346  to the MCU  110 . The web browser  340  is typically located at the customer site. A customer administrator  120  using a web browser  340  connects to a website hosted by the web server  346 . The customer administrator  120  can create conference profiles, and optionally initiate conferences and monitor conferences via this connection to the website. The web server  346  may include additional server capabilities or may interface to another server to provide conferencing control. The web server  346  provides a dial-in number for each conference profile. When a terminal  114  dials the dial-in number, the MCU  110  automatically initiates a conference. The MCU  110  also automatically connects each terminal  114  that dials this dial-in number. When all participants disconnect, the MCU  110  terminates the conference. This conference can be initiated anytime at the will of the participants simply by dialing the dial-in number as long as resources are available. 
     Referring again to  FIG. 2 , the initial steps required in this embodiment of the present invention will be described. Similar to the first embodiment, the customer that initiates the conference, the customer administrator  120 , will be referred to as the moderator. 
     Initially, the moderator  120  creates a conference profile  270 . To accomplish this, the moderator  120  connects to the web service and logs onto the web server  346  (for example: by providing a user name and a password). The moderator  120  is presented with a conference profile form for defining the conference parameters. The conference parameters may include the maximum bit-rate, whether or not transcoding is to be used, the video layout, whether the conference is a dial-in or a dial-out conference (in a dial-in conference the participant calls the dial-in number, in a dial-out conference the MCU calls the participants), or the like. Optionally, these parameters can have default values so the moderator  120  does not have to provide them. The moderator  120  is not required to enter the conference start-time, duration, or the number of participants in the conference. 
     Once the conference profile is completed, or as information is provided by the moderator  120 , the conference profile form, and/or information, is sent via the web browser  340  to the web server  346 . Next, a conference dial-in number is allocated  272 . The web server  346  then allocates a dial-in number for the conference  272 . The web server  346  is configured to have a range of dial-in numbers, and it allocates them to conference profiles using an assignment algorithm similar to that described in the first embodiment. After assigning a dial-in number, the web server  346  notifies the moderator  120  with the allocated dial-in number  274  through the web browser  340 . In addition, the web server  346  may optionally notify the MCU  310 , or other conference participants with the new conference profile parameters and its dial-in number. 
     The web server  346  provides the dial-in number to the moderator  120 , or optionally any participant in the conference  276 . The moderator  120  can distribute the conference dial-in number to the other participants or terminals  314  of the conference using a telephone, regular mail, e-mail, facsimile, or other similar means. 
     Once a conference profile has been created, the moderator  120  can delete the conference profile by contacting the web server  346  using the web browser  340 . The web browser  340  will show the moderator  120  a list of existing conference profiles and the moderator  120  may select to delete one or multiple of these conference profiles. When a conference profile is deleted, the web browser  340  notifies the web server  346 . In response to receiving this notice, the web server  46  removes the conference profile record from its internal storage  362 . The web server  346  may optionally notify the MCU  110  that the conference profile has been deleted. The MCU  110  may then proceed to delete the conference profile from it&#39;s internal memory  360 . The dial-in number previously assigned can then be allocated to new conference profiles. 
     In a dial-out conference, when the moderator  120  wishes to start the conference, he connects to the web server  346  using the web browser  340 . The moderator  120  is presented with an option to start the conference identified in the conference profile. When the moderator  120  selects to start the conference, the command is sent to the web server  346 . The web server  346  then sends a message to the MCU  110  to start the conference immediately. In a dial-in conference, the moderator or any other participant may start the conference by dialing the dial-in number. The start-time of the conference is the current time and the duration of the conference will be a pre-defined time T. The actual value of T is part of the conference profile. 
     Once the conference is started on the MCU  110 , the participants may join the conference by calling the dial-in number from their terminals  114 . 
     The remaining steps illustrated in  FIG. 2  are common to both the above-described first and second embodiments of the present invention. For each terminal  114  that a participant uses to request entrance into the conference  279 , the requesting terminal  114  simply initiates a call to the dial-in number  280 . As each terminal  114  joins the conference, the MCU  110  uses an auto-detection procedure  282  to identify the connecting terminals  114  and their parameters. The auto-detection procedure  282  ensures that all terminals  114  connect to the conference successfully. More specifically, the goal of the auto-detection procedure  282  is to determine the connection rate for the requesting terminal  114 , and the type of terminal that is making the request. Initially, the MCU  110  receives, with the connection message from the terminal  114 , information about the type of the call that the terminal  114  is initiating. In an exemplary embodiment, this step can be performed in accordance with the Q.931 standard, which is known to those skilled in the art. If the call type is VOICE (for example: a PSTN phone device), the MCU  110  decides that the terminal  114  is a voice only terminal, which uses a single channel. The MCU  110  continues the connection procedure for a voice terminal. The exact steps required for this process are known to those skilled in the art and are more thoroughly describe in the ITU standards H.242 and H.221. 
     If the call type is not VOICE, the MCU  110  attempts to connect to the terminal  114  in a technique known as Bandwidth On Demand Interoperability Group (“BONDING”). BONDING is a method of aggregating communication channels. This is a technique of aggregating B channels at the bit level. B channels are basic user channels that do not carry signaling information. If the BONDING connection succeeds, the terminal  114  requests a connection rate using the BONDING protocol. The MCU  110  adopts this rate as the terminal connection line rate and continues with the connection procedure for a BONDING terminal. However, if the BONDING negotiation fails (e.g., a time out has occurred because there was no valid response from the terminal), the MCU  110  reverts to H.221 negotiation mode and tries to exchange capabilities with the terminal following the procedure described in the ITU standards H.242 and H.221. 
     If the H.221 capabilities exchange succeeds, the terminal  114  notifies the MCU  110  of its highest connection rate capabilities. The MCU  110  selects the terminal communication rate as the minimum of the terminal maximum rate (known by the terminal capabilities) or the conference maximum rate (the conference maximum rate is part of the conference profile). 
     Once the line rate and the terminal type are identified using the auto detection procedure  282 , the MCU  110  determines if there are enough available resources for the terminal  114 . The MCU  110  keeps a record of the total number of currently available resources and their types. For example, a resource type can be an audio codec, a video codec, or the like. A codec is a device used to decode or encode data and the various types and operations of a codec are known to those skilled in the art. The MCU  110  checks if the number of free (unused) resources is higher than or the same as the number of resources needed for the terminal  114  to connect to the conference  284 . If sufficient resources are available, the terminal  114  is connected to the conference  288 . The number of resources required by the terminal  114  are then deducted from the total number of available resources maintained and monitored by the MCU  110 . However, if the MCU  110  determines that insufficient resources are available for the terminal  114 , the terminal  114  is disconnected  286  from the MCU  110 . 
     Conference Control and Monitoring 
     Another aspect of the present invention is to provide a method to control and monitor a video conference. During the conference, participants with access to a web browser  340  can be connected to the web server  346  to monitor and, optionally, control the conference though the web browser  340 . The conference status (e.g., the number of connected parties, state of the video mute for each party, state of the audio mute for each party) is automatically updated and displayed on the browser screen. Participants can perform actions on the conference terminals  114  such as, connecting or disconnecting parties, activating or deactivating video or audio mute, requesting to extend the conference time, terminating the conference, or the like. 
     Conference Termination 
       FIG. 4  is a flow diagram illustrating the operation of performing the auto terminate aspect of the present invention. The auto termination algorithm is used to terminate a conference when it is no longer active (i.e., no terminals are connected). This process can be performed without prior knowledge of the conference duration. Advantageously, the auto termination process prevents inactive conferences from taking up resources that could be used by other conferences. 
     Each conference established through the use of the present invention includes two configurable time periods. One time period (“T 1  or before-first-join”) is the time limit for joining the conference. If no terminals connect to the conference within the T 1  time period from starting the conference, the conference is automatically terminated. Another time period (“T 2  or after-last-quit”) is the time limit for holding the conference after the last participant has left the conference. If a party connects to the conference within the T 2  time period, the termination count-down is stopped. In operation, the MCU  110  starts or accepts a conference initiation  400 . The MCU activates the auto terminate feature only after at least one participant fully connects to the conference. Once a terminal is connected, the MCU  110  then sets a first timer (“Timer A”) to the value of the T 1  time period  402 . Once the auto terminate feature is active, the MCU activates the count-down timers A and B when it detects that there are no active participants, either connecting, partially connected or fully connected, in the conference. If Timer A expires  408  prior to another terminal being connected  404 , the MCU will terminate the conference  410 . If another terminal is connected prior to Timer A expiring, the MCU will stop the Timer A count-down  406 . Once all of the terminals are disconnected from the conference  412   414 , the MCU will set a second timer (“Timer B”) to the T 2  time period and initiate the count-down of the Timer B. If Timer B expires prior to a terminal connecting to the conference  404 , then the conference will be terminated. Otherwise, the count-down of Timer B will be halted  406  and the conference will continue. 
     If time periods T 1  or T 2  are zero, the auto terminate feature will not be active. In this state, the web browser  340 , an operator, or an H.243 chair control terminal can be used to terminate the conference. 
     Although the auto terminate feature is described as being included in the reservationless conferencing system, those skilled in the art will appreciate that this aspect of the present invention may also be used in reservation-based conferencing systems. In either system, because the MCU&#39;s  110  resources are limited, a conference may have to be terminated to facilitate beginning a new reserved conference. 
     Auto Extension of Conference 
       FIG. 5  is a flow diagram illustrating the auto extension aspect of the present invention. Conferences initiated with embodiments of the present invention do not require a duration or a termination time. Instead, a pre-defined, MCU configured duration is used as a default duration. However, to prevent terminating a conference prior to it&#39;s natural ending, an auto extension algorithm may be incorporated into embodiments of the present invention. The auto extension algorithm extends a reservationless conference as long as resources are available, and optionally provides an audio tone warning to participants before the conference is terminated. 
     The system assigns three time intervals to each conference: 
     T 3 —minimum conference time; 
     T 4 —audio tone warning time prior to end of conference; and 
     T 5 —conference extend interval. 
     Preferably, T 4  is less than or equal to T 3  and/or T 5 . Upon initiation of a conference  530 , the MCU  110  determines if sufficient resources are available for the conference to be active for a T 3  time period  546 . If sufficient resources are not available, the MCU  110  will abort the initiation of the conference  548 . If sufficient resources are available, the MCU  110  will set a first timer (“Timer A”) to time period T 3 , set a second timer (“Timer B”) to a time period determined by the difference of T 3  and T 4 , and start both Timer A and Timer B  532 . If Timer A times out  534 , the MCU  110  will terminate the conference  536 . If Timer B times out, the MCU will determine if sufficient resources are available for the conference to be extended for a time period of T 5   540 . If sufficient resources are available, the MCU  110  will extend the conference duration by a time period of T 5  by (a) stopping Timer A and Timer B, (b) setting Timer A to time period T 5 , setting Timer B to a time period determined by the difference of T 5  and T 4 , and (c) starting Timer A and Timer B  542 . This allows the conference to continue, or to be automatically extended by the time period of T 5 . If sufficient resources are not available, the MCU  110  will play an audio tone  544  to notify the participants that the conference may be terminating soon. If the MCU  110  detects that sufficient resources are available prior to the expiration of Timer B, then the conference can be extended by a time period of T 5  by (a) stopping Timer A and Timer B, (b) setting Timer A to time period T 5 , setting Timer B to a time period determined by the difference of T 5  and T 4 , and (c) starting Timer A and Timer B  542 . 
       FIG. 6  is a screen image of an exemplary embodiment of a user interface showing conference profile settings. In an exemplary embodiment of the present invention, a user interface  605  is provided for the user to specify a conference profile. Those skilled in the art will appreciate that alternate user interfaces may be used to allow the user to specify the conference profile. 
     The present invention has been described in relation to particular embodiments which are intended in all respects to be illustrative rather than restrictive. Those skilled in the art will understand that the principles of the present invention may be applied to, and embodied in, various program modules for execution on differing types of computers and/or equipment, operating in differing types of networks, regardless of the application. 
     Alternate embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is described by the appended claims and supported by the foregoing description.