Lesson 3: Online Conferencing

Microsoft Exchange 2000 Conferencing Server is Microsoft's most powerful real-time collaboration platform. It is a separate product that enables you to manage and coordinate virtual meetings and online conferences. Exchange 2000 Conferencing Server is fully compliant with the T.120 recommendation of the International Telecommunications Union (ITU) and supports IP multicast audio and video streams. Clients, such as Microsoft NetMeeting, can use the T.120 protocol to join a data conference. A client for videoconferences is available in the form of an ActiveX control.

This lesson introduces Exchange 2000 Conferencing Server. It covers the basics of data and video conferencing and explains the advantages of client/server in contrast to peer-to-peer conferencing. You can also read about the most important components of Exchange 2000 Conferencing Server and the scheduling of online meetings with Microsoft Outlook 2000.


At the end of this lesson, you will be able to:

  • Describe the advantages of Exchange 2000 Conferencing Server for online data and video conferencing.
  • Explain how online conferences are scheduled using Outlook 2000.

Estimated time to complete this lesson: 45 minutes


Data and Video Conferencing Overview

Data conferencing allows participants in virtual meetings to share applications, transfer files, exchange information on a whiteboard, collaborate through a shared clipboard, and communicate via text-based chat. Audio and video conferencing, on the other hand, provide participants with the capability to send and receive audio and video streams based on IP multicasting, which is an extension to IP for efficient group communication.

Online conferencing technologies offer the following characteristic features:

  • Application Sharing. Users can share programs running on their computers with other participants without any special knowledge of the application capabilities. Only the person who wants to share a program must have the application installed. Participants do not require a local copy of the software to view the information or see how the content is edited or scrolled.
  • Audio and Video Conferencing. Participants in a conference can send and receive audio and video streams.
  • Chat. Participants in a conference can exchange text-based messages to share common ideas or meeting notes with other participants. Chat may be the basis for communication in the absence of audio support.
  • File Transfer. Participants in a conference can send files to one or all other participants based on the T.127 standard. Recipients can accept or decline the file transfer.
  • Shared Clipboard. Participants in a conference can exchange information by means of a shared clipboard, which allows cut, copy, and paste operations between separate computers.
  • Whiteboard. Participants in a conference can simultaneously use a whiteboard to work with graphic information.

Peer-To-Peer Versus Client/Server Conferencing

Microsoft NetMeeting 3.01 or later is a typical client application for data conferencing. NetMeeting includes a multipoint control unit (MCU), which interconnects conference participants and distributes conference data. However, each client connection to an MCU in a peer-to-peer conference requires NetMeeting to send a separate copy of the data. Hence, if you want to send data to N users, your client must send data through N connections (see Figure 25.10). This can represent a significant drain on the network bandwidth. Slow dial-up connections may not even be suitable for hosts of one-to-many type peer-to-peer conferences. If the link to the computer of the meeting organizer is disconnected, the entire conference is terminated. Furthermore, NetMeeting does not provide a scheduling facility. Without central management of online conferences, it is difficult to join a conference or invite others.

To overcome the limitations and disadvantages of peer-to-peer conferencing, Exchange 2000 Conferencing Server can be used to establish an MCU on a central server. In this client/server conferencing scenario, clients connect to the central server to send and receive data over a single connection, while the server keeps all clients synchronized. Because the conference is now hosted on the server, the meeting organizer can leave the conference without terminating the online meeting.

Server-based MCUs can be placed at the ends of wide area network (WAN) links to minimize the bandwidth consumption on slow connections. Participants can connect to the MCU closest to their physical locations on the network, while the MCUs send single instances of data across the WAN links (see Figure 25.10). Exchange 2000 Conferencing Server automatically directs clients to their closest servers.

click to view at full size

Figure 25.10 Peer-to-peer versus client/server conferencing

NOTE


Exchange 2000 Conferencing Server supports the full set of T.120 conferencing facilities and allows you to establish a client/server data conferencing environment. In addition, Exchange 2000 Conferencing Server supports audio and video conferencing based on IP multicasts.

Architecture of Exchange 2000 Conferencing Server

Exchange 2000 Conferencing Server provides three key components to overcome the limitations inherent to peer-to-peer conferencing. They are the Conference Management Service, the Data Conference Service, and the Video Conferencing Service (see Figure 25.11). Additional conference technology providers may be available from independent software vendors.

click to view at full size

Figure 25.11 The architecture of Exchange 2000 Conferencing Server

Conference Management Service

The Conference Management Service manages conferencing providers and resources. This component contains a resource reservation agent, which provides users with the ability to schedule online meetings based on conference resource accounts with Outlook 2000. The Conference Management Service keeps track of and controls access to online conferences.

The Conference Management Service is responsible for the following tasks:

  • Monitoring of conference resources. The Conference Management Service maintains a synchronized meeting definition within a conference calendar mailbox and keeps track of new meetings, changes to existing conferences, and cancellations.
  • Controlling of conferencing providers. The Conference Management Service allows providers (such as the Data Conference Service) to host online meetings according to conference schedules and other properties.
  • Redirecting of clients. The Conference Management Service redirects clients that want to join an online conference to the server that is hosting the meeting.

Conference Calendar Mailbox

Conferences are started, managed, and closed by the server, but they are scheduled within Outlook 2000. You can do this by creating a meeting request and inviting a conference resource (in addition to meeting participants), as explained later in this lesson. If the conference request is accepted, the Conference Management Service stores the conference details, such as security level and conference participants, in the conference calendar mailbox and updates the conference resource mailbox's free/busy information. Additional information, such as a description of multicast videoconferences for the Video Conferencing Service, may also be associated with online conferences. Before you can schedule an online conference, you need to assign a conference calendar mailbox to the Conference Management Service.

NOTE


To create the conference calendar mailbox, create and mailbox-enable the desired account in Active Directory Users and Computers. After that, use Exchange System Manager to assign the conference calendar mailbox to the Conference Management Service object.

Data Conference Service

The Data Conference Service gives T.120-compliant clients, such as NetMeeting 3.01, the capability to share applications, clipboards, whiteboards, and chat services in a client/server environment, as explained earlier in this lesson. The MCU unit of the Data Conference Service handles the T.120 communication. The MCU depends on Microsoft Certificate Services for private conferences that use X.509 certificates for authentication and encryption of the conference data. Without a certificate, private conferences are not supported. The MCU automatically retrieves a machine certificate from Certificate Services. Public conferences, on the other hand, are available to any participant who has access to the URL. All public conferences are listed on a general conferencing Web page with a URL in the form of http://<Server Name>/Conferencing/LIST.ASP (such as, http://BLUESKY-SRV1.bluesky-inc-10.com/Conferencing/LIST.ASP/). Conferences are public by default.

H.323 Video Conference Bridge

The MCU of the Data Conference Service also contains an H.323 video conference bridge that allows H.323-compliant client programs that are unable to participate directly in IP multicast conferences, such as NetMeeting, to participate in videoconferences through an H.323 unicast session.

Video Conferencing Service

The Video Conferencing Service supports one-to-many audio and video streams based on Telephony Application Programming Interface (TAPI) version 3.0. Based on multicast groups, data is transferred to all participants via the Real-Time Protocol (RTP) over TCP/IP. Based on RTP, each participant's client receives all other participants' audio and video streams. The data is then mixed locally on the client computer to give the impression of an online conference.

As mentioned, the Video Conferencing Service client is an ActiveX control. This control is automatically downloaded to the client computer via Conferencing Access Pages when a participant joins a videoconference for the first time. The Conferencing Access Pages form the Web site of your conferencing server. To support the ActiveX control, you need to run Windows 2000 on the client computer.

IP Multicasting

The Video Conferencing Service relies on IP multicasting to send audio and video streams to all participants simultaneously. This eliminates the need to transfer the same information multiple times (one time for each participant) over the network. With IP multicasting, only one copy of the information is sent to a group IP address that reaches all participants. IP multicasting results in a greatly reduced load on the network and the sending server. You can read more about IP multicasting in the Windows 2000 Server product documentation.

NOTE


IP multicasting requires a multicast-enabled network. IP routers must be multicast-aware.

Multicast Address Dynamic Client Allocation Protocol

To carry out the multicast communication, the Video Conferencing Service provider must obtain an available Multicast Address Dynamic Client Allocation Protocol (MADCAP) address during the start of the conference. Otherwise, data cannot be sent to the participants, and clients will not be able to join the videoconference. Consequently, you need to configure a MADCAP server to provide the address allocation services for IP multicast videoconferences.

The MADCAP service is installed as part of the Dynamic Host Configuration Protocol (DHCP) service in Microsoft Windows 2000 Server. However, MADCAP and DHCP are independent of each other. For more information regarding MADCAP servers, see the Windows 2000 Server product documentation.

Installing Exchange 2000 Conferencing Server

It is not necessary to install Exchange 2000 Conferencing Server on a server running Exchange 2000 Server. However, Active Directory and Exchange 2000 Server must be deployed in the Windows 2000 domain to successfully complete the setup process. Exchange 2000 Conferencing Server requires Windows 2000 Server and IIS 5.0 on the local server. In addition, your network must be IP multicast-enabled and must provide MADCAP services if you want to support videoconferences. For private conferences, make sure Windows 2000 Certificate Services have been configured in your organization.

The following minimum hardware is recommended:

  • 400-MHz Intel Pentium processor (or higher)
  • 256 MB of RAM
  • 50 MB of available disk space

NOTE


To install Exchange 2000 Conferencing Server, you need to be logged on as a user with Exchange Full Administrator permissions in the administrative group where you plan to add the conferencing server. Administrative permissions are also required for the Windows 2000 domain. Ideally, you are working with the privileges of an Enterprise Admin.

Installing Individual Conferencing Components

To install a complete version of Exchange 2000 Conferencing Server, launch the Setup program from the installation CD, click Next on the Welcome wizard screen, accept the License Agreement, and enter your 25-digit CD key on the Product Identification wizard screen. On the Setup Type wizard screen, click Complete. When you click Next, you will be prompted for the administrative group of the conferencing server (if there is more than one administrative group in your organization). To begin the actual installation, on the Ready To Install The Program wizard screen, click Install.

On the Setup Type wizard screen, you also have the choice to select the Custom option to display the Custom Setup wizard screen, where four components are available. Most important, you should make sure that the Conference Management Service is selected because this component represents the core service of the conferencing server. The Data Conference Service and Video Conferencing Service will be installed as part of the Conference Management Service. It is likewise a good idea to install the Conferencing Manager, which is a Microsoft Management Console (MMC)_based utility for managing and configuring conferencing services. This snap-in can be used stand-alone or as part of Exchange System Manager. Other significant elements are the Conference Access Pages, which participants use to join online conferences; the T.120 MCU/H.323 conference bridge, which provides the server-based MCU for T.120-based clients; and a bridge for H.323 clients to participate in audio and videoconferences.

NOTE


Following the installation of the conferencing server, you need to create the conference calendar mailbox and conference resources in Active Directory Users and Computers to allow your users to schedule online conferences with Outlook 2000. Detailed information about the configuration of conferencing resources is available in the Exchange Conferencing Server online documentation.

Scheduling Online Conferences

After the conferencing environment has been prepared, you can use Outlook 2000 to schedule data and videoconferences. Online meeting requests do not differ much from ordinary meeting requests. You only need to make sure that a conference resource is invited as a resource in addition to desired meeting attendees, and you need to select the This Is An Online Meeting Using check box, and then select Microsoft Exchange Conferencing.

To enable the creation of online meeting requests, you need to add the following Registry key to your workstation running Outlook 2000:

 HKEY_CURRENT_USER       \Software         \Microsoft           \Office             \9.0               \Outlook                 \ExchangeConferencing 

Joining Online Conferences

You can easily join an online conference from Outlook 2000. Right-click on the desired meeting appointment in your calendar, and then select Join Conference. (Meetings are placed in your calendar automatically when you accept the corresponding requests from the meeting organizers.) A Join Conference button is also available in the Reminder dialog box for online meetings.

If you open an online meeting appointment, you can find the complete conference URL in the Location box. You can copy this URL and paste it into your Web browser to connect to the conference. This will be required if you are not working with Outlook 2000. Your Web browser will connect to the conferencing server and then request participation in the meeting. If you are allowed to join the meeting, a Web page is returned to the browser to add you to the meeting. If you are attempting to join an online meeting that has not started, your browser will display the time and date of the conference.

NOTE


To join a data conference, a T.120 conferencing program, such as Microsoft NetMeeting 3.01, must be installed on the local computer.



MCSE Training Kit Exam 70-224(c) Microsoft Exchange 2000 Server Implementation and Administration
MCSE Training Kit Exam 70-224(c) Microsoft Exchange 2000 Server Implementation and Administration
ISBN: N/A
EAN: N/A
Year: 2001
Pages: 186

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net