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Multipoint H.323 videoconference calls of three or more participants must use a multipoint control unit. The Cisco IP/VC 3510 MCU manages the call flow-control and processes and distributes the audio, video, and data streams to the videoconference participants.
The MCU allows any LAN terminal with H.323 dialing capabilities to initiate or join a multipoint videoconference call. WAN terminals can initiate and join videoconference calls through an H.323 gateway.
This chapter describes how to initiate and join videoconference calls the MCU manages. The topics include:
To place a multipoint videoconference call, you must use an MCU service prefix in the dial string. The service prefix is associated with an MCU service that predefines the parameters the MCU will use to create the call. The service includes video bandwidth information and the number of participants the call is allowed to have. The service can also allow the call to have continuous presence and T.120 data-sharing support. In environments that have two or more Cisco IP/VC 3510 MCUs, the MCUs can cascade to allow the videoconference to have more participants than a single MCU can manage. MCU videoconferences can also be monitored using a Web browser. This section provides brief discussions about video bandwidth, number of participants, continuous presence, T.120 data sharing, cascading, and Web monitoring.
The MCU service defines the video bandwidth that the MCU is to use for processing the video streams it sends to the videoconference participants. Every participant is sent the same stream. If the bandwidth the MCU uses to process the stream (for example 384 kbps) exceeds the capacity of a given terminal (for example 128 kbps), the terminal will display poor quality video. Usually, the MCU negotiates with the participating terminals or endpoints and determines an acceptable bandwidth before processing the streams. The negotiation ensures that all terminals display the same video quality. However, the MCU allocates resources for calls based on the service parameter settings. This directly affects the ability of the MCU to place calls and the ability of other terminals to be invited to or join the videoconference. We recommend that you use a service that uses the bandwidth of the least capable participating terminal in your call to ensure that uniform quality and to best use MCU resources.
The service specifies the number of participants the MCU allocates for the call. This number is used whether or not the specified number of participants actually participates in the call. The number has a direct impact on the resources the MCU has available for calls, including the call you are initiating. We recommend that you use a service that specifies the number of participants you anticipate participating in the videoconference.
Continuous presence is a service that displays up to four of the videoconference participants on each LAN terminal monitor simultaneously. The MCU distributes a video stream with four quadrants. The call initiator and the first two participants to be invited to or to join the call appear in three of the quadrants. The fourth quadrant displays the last participant to be awarded the floor from among the remaining conference participants.
T.120 data sharing is a process that allows terminals to share information in applications in real time. The MCU provides data-sharing support for Microsoft NetMeeting and compatible applications. (Ask your MCU administrator for information about other data sharing applications that are supported.)
Data sharing is activated for participants who have data-sharing capability through an MCU Web page opened using Internet Explorer. The Web page lists the videoconference participants with active data-sharing capability and allows anyone to enable data-sharing for the participant.
T.120 data sharing is not supported across the cascaded link in cascaded videoconferences, nor is it supported over Cisco proxy links. However, participants connected to the same MCU can participate in data sharing.
Cascading is a technique in which one Cisco IP/VC 3510 MCU videoconference joins the videoconference of another Cisco IP/VC 3510 MCU as a participant. In this way, the two videoconferences are joined to make one larger videoconference. The joining MCU serves as a conduit through which information passes between one videoconference and the other.
To ensure that the participants in both videoconferences perceive quality data, both videoconferences must be initiated with similar parameters. We recommend that you use the service that specifies the bandwidth of the least capable terminal to initiate the videoconferences of all MCUs that will participate in the cascaded conference.
Cascaded conferences should be planned carefully. MCUs must not be mutually invited, because doing so causes a loopback between the two MCUs.
When more than two MCUs are participating in a cascaded conference, we recommend that all MCUs join the same conference in a starlike topology. Otherwise, terminals connected to the cascaded conference through another conference can cause delays in the reception and transmission of the audio and video streams.
MCU videoconferences can be monitored and managed using a Web browser. You can use Internet Explorer or Netscape Communicator to access the MCU and the conference password (the service prefix and conference ID) to access the Web page for the conference. Anyone can access the conference. The Web page lists information about the conference participants and allows you to invite participants, disconnect participants, and lock the camera on one participant. The disconnect and camera lock functions can be exercised only by the user who is granted chair control. Chair control is not automatically assigned but can be decided on by the participants.
Any user can initiate a videoconference call. To initiate a videoconference call for three or more participants, you must include an MCU service prefix in the dial string. The service prefix identifies the service the MCU specifies for the call. The service parameters include the number of call participants, the video bit rate, the frame rate, video format, and the picture format. The service can also specify T.120 support and continuous presence, which displays up to four videoconference participants simultaneously.
This section describes and provides examples of how to initiate videoconference calls from the LAN and the WAN. It also describes initiating calls to use continuous presence.
Table 6-1 through Table 6-4 provide the call parameters that are used in the examples. Table 6-1 provides information about the terminals that are used in the sample calls. Table 6-2 lists the MCU service prefixes and call parameters of the services that do not support continuous presence. Table 6-3 lists the MCU service prefixes and call parameters of the services that do support continuous presence. Table 6-4 lists the gateway service prefixes and call parameters.
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Note The services provided in your videoconference environment are unique to your environment. Contact your system administrator for information regarding the service prefixes and service parameters used in your environment. |
Before you dial an MCU videoconference call, we recommend that you review the parameters your call will most likely use. Ask your videoconference administrator for a list of the service prefixes you can dial. Where possible, inquire of the parties you regularly call for information about the video bit rate and frame rate supported by the endpoints they use.
| Endpoints | Video Bit Rate | Frame Rate | Picture Format | E.164 Address or Phone Number |
|---|---|---|---|---|
T1 | 512 kbps | 30 fps | 3846 | |
T2 | 128 kbps | 7.5 fps | CIF or QCIF | 3891 |
T3 | 384 kbps | 15 fps | CIF or QCIF | 3802 |
T4 | 384 kbps | 15 fps | CIF or QCIF | 3833 |
WT1 | 256 kbps | 15 fps | CIF or QCIF | 555-1212 |
WT2 | 320 kbps | 15 fps | CIF or QCIF | 000-1234 |
Outside line access code |
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| 9 |
Gateway |
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| 000-1111 |
| 1Common Intermediate Format. 2Quarter Common Intermediate Format. |
| MCU Service Prefix | Video Bit Rate | Frame Rate | Number of Participants | Picture Format | T.120 |
|---|---|---|---|---|---|
54 | 128 kbps | 7.5 fps | 4 | CIF | No |
56 | 320 kbps | 15 fps | 4 | CIF | Yes |
58 | 704 kbps | 30 fps | 3 | CIF | Yes |
| MCU Service Prefix | Video Bit Rate In | Video Bit Rate Out | Frame Rate | Number of Participants | Picture Format | T.120 | Continuous Presence Role |
|---|---|---|---|---|---|---|---|
55 | 32 kbps | 128 kbps | 7.5 fps | 4 | QCIF | No | Master |
57 | 80 kbps | 320 kbps | 15 fps | 4 | QCIF |
| Slave |
59 | 176 kbps | 704 kbps | 30 fps | 3 | QCIF | Yes | Master |
| Gateway Prefix | Call Type | Maximum Bit Rate | Restricted Mode |
|---|---|---|---|
63 | H.320 | 64 kbps | No |
64 | H.320 | 256 kbps | Yes |
65 | Video | 384 kbps | No |
To initiate a videoconference call from a LAN terminal and specify the LAN terminals you want to participate in the call, perform the following steps:
We recommend that you choose a service that has a bandwidth capacity that the least capable of the target recipients can use successfully. We also recommend that you choose an MCU service with a number-of-participants value that is close to the number of terminals that you expect to participate in the call.
Step 2 Create a conference ID for the call.
The number you create must be unique at the time the call is placed.
Step 3 Dial the following:
MCU service prefix, conference ID, ** (MCU invite code), E.164 address of the first LAN target, **, E.164 address of the second LAN target recipient
LAN terminal T1 initiates a videoconference call that includes terminals T2 and T3. Terminal T2 has the lowest bandwidth capability. To ensure that all of the conference participants receive quality video, the T1 user chooses MCU service prefix 54. The conference ID the T1 user creates is 1234. To initiate the call, the T1 user dials the following: 541234**3891**3802
To initiate a videoconference call from a LAN terminal and specify the LAN and WAN terminals you want to participate in the call, perform the following steps:
Step 2 Choose the appropriate MCU service prefix.
We recommend that you choose a service that has a bandwidth capacity that the least capable of the target recipients can use successfully. Include the gateway service parameters in your consideration. We also recommend that you choose an MCU service with a number-of-participants value that is close to the number of terminals that you expect to participate in the call.
Step 3 Create a conference ID for the call.
The number you create must be unique at the time the call is placed.
Step 4 Dial the following:
MCU service prefix, conference ID, ** (MCU invite code), E.164 address of the first LAN target, **, E.164 address of the second LAN target recipient, **, gateway service prefix, telephone access code, telephone number of WAN target recipient
LAN terminal T1 initiates a videoconference call that includes LAN terminals T3 and T4 and WAN terminal WT1. The video bit rate for WT1 is 256 kbps. The appropriate gateway service prefix to use for this terminal is 64. The appropriate MCU service to use for videoconference is service prefix 54. The conference ID the T1 user creates is 1342. To initiate the call, the T1 user dials the following: 541342**3891**3802**3833**6495551212
To initiate a videoconference call from a WAN terminal and to specify the LAN terminals you want to participate in the call, perform the following steps:
We recommend that you choose a service that has a bandwidth capacity that the least capable of the target recipients can use successfully. We also recommend that you choose an MCU service with a number-of-participants value that is close to the number of terminals that you expect to participate in the call.
Step 2 Create a conference ID for the call.
The number you create must be unique at the time the call is placed.
Step 3 Dial the gateway telephone number to connect to the LAN. The gateway interactive voice response (IVR) operator answers the call.
Step 4 At the IVR prompt, dial the following:
MCU service prefix, conference ID, ** (MCU invite code), E.164 address of first LAN terminal, **, E.164 address of second LAN terminal
WAN terminal WT1 initiates a videoconference call that includes LAN terminals T1, T3, and T4. WT1 has the lowest bandwidth capacity. The appropriate MCU service to use for videoconference is service prefix 54. The conference ID the T1 user creates is 1423. To initiate the call, the WT1 user dials the gateway telephone number: 000-1111 The IVR operator answers the call and prompts the user to enter the number of the party the user wants to be directed to. The WT1 user enters the following: 541423**3846**3802**3833
Users can initiate a videoconference without inviting participants. Participants must dial in to join the call. This section describes how to initiate a videoconference without inviting participants and how participants can join the call.
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Note Participant terminals that do not support the bandwidth capacity specified by the MCU service can experience degradation in video quality. |
To initiate a videoconference call from a LAN terminal, perform the following steps:
We recommend that you choose a service that has a bandwidth capacity that the least capable of the target recipients can use successfully. We also recommend that you choose an MCU service with a number-of-participants value that is close to the number of terminals that you expect to participate in the call.
Step 2 Create a conference ID for the call.
The number you create must be unique at the time the call is placed.
Step 3 Provide the participants with the following information:
Step 4 Dial the following:
MCU service prefix, conference ID
The LAN terminal T1 user initiates the videoconference call. The user chooses the MCU service prefix 56. The conference ID the user creates is 9876. To initiate the call, the T1 user dials the following: 569876
To initiate a videoconference call from a WAN terminal, perform the following steps:
We recommend that you choose a service that has a bandwidth capacity the least capable of the target recipients can use successfully. We also recommend that you choose an MCU service with a number-of-participants value that is close to the number of terminals that you expect to participate in the call.
Step 2 Create a conference ID for the call.
The number you create must be unique at the time the call is placed.
Step 3 Provide the participants with the following information:
Step 4 Dial the gateway telephone number that you use to access the LAN. The IVR operator answers.
Step 5 At the IVR operator prompt, enter the following:
MCU service prefix, conference ID
The WAN terminal WT1 user initiates the videoconference call. The user choose the MCU service prefix 54. The conference ID the user creates is 9768. To initiate the call, the WT1 user dials the gateway telephone number: 000-1111 The IVR operator answers the call and prompts the user to enter the number of the party the user wants to be directed to. The user enters the following: 549768
To join a videoconference from a LAN terminal, perform the following steps:
Step 2 Dial the number as follows:
Videoconference ID
The LAN terminal T3 user wants to join a videoconference call. The user obtains the videoconference ID, 569876, from the videoconference initiator. To join the conference, the T3 user dials the videoconference ID: 569876
To join a videoconference from a WAN terminal, perform the following steps:
Step 2 Dial the gateway telephone number that you use to connect to the LAN. The IVR operator answers.
Step 3 At the IVR operator request, enter the following:
Videoconference ID
The WAN terminal WT1 user wants to join a videoconference call. The user obtains the videoconference ID,549768 from the videoconference initiator. The user dials the gateway telephone number: 000-1111 The IVR operator answers the call and prompts the user to enter the number of the party the user wants to be directed to. The user enters the videoconference ID:
549768
Continuous presence is a feature that allows up to four video conference participants to be visible simultaneously on each participating LAN monitor. To accomplish this, the MCU takes information it receives from the participating terminals and creates a single videoconference stream. The resultant stream is distributed to the participants. This stream projects four quadrants on the recipient monitor, each displaying the image of a participant: the current speaker and the previous three speakers.
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Note Continuous presence is not supported for WAN terminals. In calls where continuous presence is used, WAN terminals receive the image of the current speaker only. |
To use the continuous presence feature, you must select an MCU service that has the continuous presence parameter enabled. See your system administrator for a listing of services in which the MCU supports continuous presence.
The LAN T1 user wants to initiate a videoconference call that uses continuous presence and invite T3. For the call, the user selects MCU service prefix 57, which supports continuous presence calls, and creates the conference ID 5467. To initiate the call, user dials the following: 575467**3802
You can use the Cisco IP/VC 3510 MCU Web page to manage an MCU videoconference. The Web page can be accessed using Microsoft Internet Explorer 3.0 or later and Netscape Navigator. The Web page allows you to:
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Note The MCU provides native data-sharing support for Microsoft NetMeeting applications only. You must open a Web page using Microsoft Internet Explorer to display and use the faculties that provide the native data-sharing support. For information about external T.120 support, see the August 2000 or later Release Notes for Cisco IP/VC 3500 Series Product Family. |
To launch the MCU videoconference Web page for a videoconference call, perform the following steps:
Step 2 In the Location field, enter the MCU IP address or domain name and press Enter.
Ask your videoconferencing administrator for the IP address or domain name. The Cisco IPVC-3510-MCU Web page appears. (See Figure 6-1.)
Step 3 Enter the videoconference ID.
Ask the call initiator for the videoconference ID (the MCU service prefix and the conference ID).
Step 4 Click OK. The page displaying the conference participants appears.
The page displaying the conference participants provides information about the terminals that have joined the conference and lets users perform videoconference call management functions. (See Figure 6-2.)
Participant information includes the following:
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Note The participant listed first is the videoconference initiator. The videoconference ends when the initiator disconnects or is disconnected from the conference. |
The function buttons include the following:
Any Web page user can invite a new participant to the videoconference. The participant can be a LAN terminal, a WAN terminal, or another MCU videoconference.
To invite a new participant using the MCU videoconference Web page, perform the following steps:
Step 2 In the field, enter the number required to contact the participant you want to invite as follows:
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Note You can invite multiple participants at one time. To invite multiple participants at one time, insert ** between the dialing numbers. You can have up to 200 characters in the invite field. |
Step 3 Click OK to confirm. The MCU places the call.
Step 4 To ensure that the call connects, click Refresh.
If the call is successful, the invited party appears as a participant on the Web page. The invite code ** appears next to the name of the participants that have been invited to the conference.
The following samples describe how to invite different types of terminals to join a videoconference call. Example 6-9 shows how to use the Web page to invite a LAN terminal. Example 6-10 shows how to use the Web page to invite a LAN terminal. Example 6-11 shows how to use the Web page to invite an MCU videoconference to cascade conferences. Example 6-12 shows how to invite multiple participants at one time.
A Web user connected to the MCU videoconference 541234 wants to invite T4 to participate in the conference. To invite T4, the Web user enters the E.164 address for T4 in the Enter the number of party to invite field. The user enters 3833 and clicks OK.
A Web user connected to the MCU videoconference 541234 wants to invite WT1 to participate in the conference. To invite T1, the Web user enters the appropriate gateway prefix, the access code to get an outside line, and the WT1 telephone number. The user enters 6395551212 and clicks OK.
A Web user connected to the MCU videoconference 541234 wants to cascade MCU videoconference 544321. To invite MCU videoconference 544321, the Web user enters the joining MCU videoconference ID. The user enters 544321 and clicks OK.
A Web user connected to the MCU videoconference 562341 wants to invite LAN terminals T3 and T4 and WAN terminal WT2. To invite the terminals, the user enters the T3 E.164 address; **; the T4 E.164 address; **; and the appropriate gateway service prefix, the access code to get an outside line, and the WT2 telephone number. The user enters 3802**3833**6590001234 and clicks OK.
Chair Control is not automatically assigned. Any Web page user can access
Chair Control and perform the functions. Only one user at a time can claim chair control. The first user to claim the Chair Control manages the function until relinquishing the function.
Chair Control is granted exclusively for the current MCU videoconference. In cascaded conferences, Chair Control can only be used to manage functions of the local videoconference. It cannot be used to manage functions of the joining MCU videoconference or of the joined MCU videoconference. To use Chair Control to manage participants in a cascaded conference, a Web page must be opened for each conference that is to be managed, and Chair Control claimed for each one.
To claim Chair Control, click Chair Control.
The status bar displays the following message unless chair control is granted to another user:
Chair control granted
The Chair Control button is replaced with the Chair Release button. (See Figure 6-4.)
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Note If you are participating in the conference from the PC on which you have accessed the MCU videoconference Web page, your participant entry appears in bold. |
If you close your browser without releasing Chair Control, the MCU automatically releases it after 3 minutes. Once released, Chair Control is once again available upon request.
The status bar displays the following message when chair control is requested, but is already granted:
Chairman not granted
Chair Control allows the Web page user to disconnect conference participants. When the disconnected participant is a cascaded MCU, the disconnected MCU continues its conference. As a result, the combined conference becomes two independent conferences.
To disconnect a participant, perform the following steps:
Step 2 Click Disconnect. A confirmation message appears at the bottom of the left frame.
Step 3 Click OK to confirm. The selected participant is disconnected from the conference and the page is updated.
Chair Control allows you to lock the conference video broadcast on one participant. All other participants view the participant that the video is locked on. The participant on whom the video broadcast is locked sees the last participant to speak.
To lock the conference on one participant, click the radio button of the participant you want to lock the conference video on. Click Lock/Unlock. The participant conference information for the participant appears in a different color.
To unlock the participant, click the radio button of the locked participant and click Lock/Unlock.
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Note If you try to lock the video broadcast on a participant that does not have a video camera or video capturing capabilities, locking does not take place and the following message is displayed in the status bar: This participant does not send any video. |
To lock the video broadcast on a single participant in a cascaded conference on one participant, perform the following steps:
Step 2 Click Lock/Unlock. The participant conference information for the MCU participant appears in a different color.
Step 3 For each cascaded videoconference, click the radio button of the participating MCU.
Step 4 Click Lock/Unlock. The participant conference information for the MCU participant appears in a different color. All of the participants in the MCU videoconference will see the locked participant.
The MCU videoconference Web page allows the Web page user to activate data sharing for conference participants that display data-sharing capability. The data-sharing faculty appears only on the Web page when the following conditions apply:
If all of the conditions apply, the Data Sharing button appears on the left side of the Web page and Microsoft NetMeeting or the data-share application name appear in the Type field for the participant in the Participants in Conference list. Any Web user can enable participants with data-sharing capability to participate in data collaboration. All participants with the same application can share the data.
To enable participants with data-sharing capability to access the shared data, perform the following steps:
Step 2 Click Data Share. The data-sharing board opens on the terminal of the selected participant.
Step 3 Repeat Step 1 and Step 2 for each participant that you want to have access to the shared data.
Posted: Wed Sep 20 09:15:02 PDT 2000
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