On-Premise Web Conferencing

Multimedia Capabilities

Office Communications Server 2007 conferences provide a rich multimedia experience that include data collaboration, group IM, audio and video, and multiparty audio conferencing. For each media type there is a corresponding conferencing server, or MCU (multipoint control unit), that manages and coordinates use of that media type during the course of a meeting. Office Communications Server 2007 ships with four conferencing servers:

• IM Conferencing Server. Provides server-managed group IM.

• Web Conferencing Server. Enables multiparty data collaboration.

• A/V Conferencing Server. Enables audio and video conferencing.

• Telephony Conferencing Server. Enables audio conference integration with ACPs (audio conferencing providers).

The IM Conferencing Server and Telephony Conferencing Server always run as separate processes on the Standard Edition server or Enterprise Edition Front End Server. The Web Conferencing Server and A/V Conferencing Server can optionally be deployed on separate computers within an Enterprise pool.

Office Communications Server 2007 also supports multimedia conferencing with external users. This capability requires deploying the following media-specific edge servers in the corporate perimeter network:

• Access Edge Server. Validates and forwards SIP signaling traffic between internal and external users. Access Edge Server is the new name for what was known in Live Communications Server 2005 as the Access Proxy.

• Web Conferencing Edge Server. Enables data collaboration with external users.

• A/V Edge Server. Enables audio and video conferencing and A/V peer-to-peer communications with external users who are equipped with the Office Communicator 2007 client. Peer-to-peer communications traverse between the clients and do not go through the A/V Conferencing Server.

These edge servers can be installed on a single computer or on separate computers. For reasons of economy and simplicity, the recommended deployment for most organizations is to collocate the Web Conferencing Edge Server with the Access Edge Server but to install the A/V Edge Server, which requires greater bandwidth, on a separate computer. Group IM and data collaboration with external users also requires deploying an HTTP reverse proxy in the perimeter network.

The following sections discuss the four main types of multimedia conferencing:

• Group IM

• Data collaboration

• Audio/video

• Audio conferencing provider support

User Roles

Meeting participants fall into three groups:

• Organizer. The user who creates a meeting, whether impromptu or by scheduling. An organizer must be an authenticated enterprise user and have control over all end-user aspects of a meeting.

• Presenter. A user who is authorized to present information at a meeting, using whatever media is supported. A meeting organizer is by definition also a presenter and determines who else can be a presenter. An organizer can make this determination when a meeting is scheduled or while the meeting is under way.

• Attendee. A user who has been invited to attend a meeting but who is not authorized to act as a presenter.

A presenter can also promote an attendee to the role of presenter during the meeting.

User Types

Meeting participants can also be categorized according to their location and credentials. Administrators can use both of these characteristics to specify which users can have access to meetings. Users can be divided broadly into internal and external users:

• Internal users have Active Directory credentials within the enterprise and connect from locations inside the corporate firewall.

• External users are those who temporarily or permanently connect to an enterprise from locations outside the corporate firewall. They might have Active Directory credentials. Office Communications Server 2007 provides conferencing support for the following types of external users:

  • Remote users have a persistent Active Directory identity within the enterprise. They include employees who are working at home or on the road, and others, such as employees of trusted vendors, who have been granted enterprise credentials for their terms of service. Remote users can create and join conferences and act as presenters.

  • Federated users possess valid credentials with federated partners and are therefore treated as authenticated by Office Communications Server 2007. Federated users can join conferences and be promoted to presenters, but they cannot create conferences in enterprises with which they are federated.

  • Anonymous users do not have an Active Directory identity and are not federated with the enterprise.

Customer data shows that many conferences involve external users. Those same customers also want reassurance about the identity of external users before allowing those users to join a conference. As the following section describes, Office Communications Server 2007 limits meeting access to those user types that have been explicitly allowed and requires all user types to present appropriate credentials at the time of entering a meeting.

Meeting Security and Access

To help ensure the privacy and confidentiality of meetings, a number of security features have been integrated into on-premise conferencing. All messaging and media are encrypted, as in Live Communications Server 2005. Office Communications Server 2007 provides additional safeguards for on-premise conferencing:

• Role-based security and authorization for conference control

• Scheduling permitted only to users who have Active Directory credentials in the internal network and are enabled for Office Communications Server 2007

• Conference passwords and digest authentication required for anonymous users to join meetings

Administrators can configure their Office Communications Server 2007 multimedia conferencing infrastructure to support meetings that include only the following types of users:

• Internal users only. If you do not deploy edge servers, all participants have persistent Active Directory identities within the enterprise and can connect only from within your organizations firewall.

• Authenticated users only. All participants have Active Directory identities within the enterprise or within a federated enterprise, and they can connect from inside or outside your organizations firewall.

Meetings that are open only to authenticated users can be of one of two types:

• Open Authenticated. All enterprise users can join the meeting. They join as attendees unless they have been designated as presenters by the meeting organizer. Federated users can join the meeting as attendees if they are invited by the organizer. Federated users cannot join the meeting as a presenter, but they can be promoted to presenter during the meeting.

• Closed Authenticated. Only authenticated users who are on the meeting organizers presenter and attendee lists are allowed to attend a closed authenticated meeting. For example, a work group or business unit might designate its regularly scheduled meeting as closed authenticated.

• Anonymous Allowed. A meeting to which anonymous users can be invited. The meeting organizer must be authorized to invite anonymous users to create a meeting of this type. Enterprise users join as attendees unless they have been designated as presenters by the meeting organizer. Anonymous users join only as attendees, although they can be promoted to the presenter role by the meeting organizer after they have entered the meeting. To enter a meeting, anonymous users must present a conference key, which they receive in an e-mail meeting invitation, and they must pass digest authentication.

Meeting Creation

An Office Communications Server 2007 user can create a meeting in one of the following ways:

• By scheduling a Web conference or conference call from the Conferencing Add-in for Microsoft Outlook.

• By creating a multiparty IM or A/V conferencing session from the Office Communicator 2007 client.

• By using the Share Information Using Live Meeting option in the Office Communicator 2007 client.

• By creating an unscheduled meeting by using the Meet Now functionality of the Microsoft Office Live Meeting 2007 client.

• By scheduling a Web conference or audio conference by using the Web Scheduler tool. You can download the tool from the Microsoft Web site at https://r.office.microsoft.com/r/rlidOCS?clid=1033&p1=websched.

When a meeting is created, a record is created in the back-end meeting database. The record contains essential information about the meeting, such as conference ID, organizer SIP URI, predefined presenter list, predefined attendee list, and anonymous user access key. This information is used by the server to activate the meeting at run time and to control who is admitted to the meeting.

Meeting Activation

A meeting is activated when the first participant successfully joins the meeting. The first user who joins the meeting can be an enterprise user, a federated user, or an anonymous user. Users are allowed to join the meeting regardless of their presenter or attendee role.

When a meeting is activated, an instance of the meeting, called the Focus, is created on the Office Communications Server front-end server. The Focus performs the following functions:

• Authenticates and authorizes participants according to the organizers meeting policy, as assigned by the server administrator

• Maintains a list of participants in the meeting that includes the following:

  • Participants who are connected to the Focus

  • Participants who are connected to each conferencing server

• Maintains the state for each conferencing server

• Maintains the state of the meeting (such as locked/unlocked)

A meeting can be activated at any time from the time the meeting is created until the meeting expires.

Meeting Deactivation

A meeting is deactivated when the Focus instance of the meeting is removed from the Front End Servers. A meeting can be deactivated any time after it is activated in the following ways:

• The organizer or a presenter manually ends the meeting.

• An administrator disables the meeting organizer for Office Communications Server or deletes the meeting organizers user account from Active Directory.

• All participants leave the meeting.

• Twenty-four hours (the default) have passed since the last participant joined the meeting. For details about changing the default setting, see the Microsoft Office Communications Server 2007 Administration Guide.

• Ten minutes (the default) have passed without an authenticated enterprise user being in the meeting. For step-by-step instructions about changing the default setting, see the Microsoft Office Communications Server 2007 Administration Guide.

When a meeting is deactivated, all remaining attendees are disconnected, all transient state information is deleted from the server, and all resources that were allocated for the meeting from instant messaging, audio conferencing providers (ACP), A/V Conferencing Servers, or Web Conferencing Servers are released.

A deactivated meeting still exists in the back-end meeting database and can be reactivated at any time until the meeting expires as described in the following section.

Meeting Expiration

To save disk space, Office Communications Server does not store meetings and their content indefinitely. When you create a meeting, the meeting is given an expiry time. When a meeting expires, the meeting data record is deleted from the back-end meeting database and all content data associated with the meeting is deleted. After a meeting expires, no participants, including the organizer, can join the meeting.

By default, the expiry time is based on the criteria:

• For a one-time scheduled meeting, the expiry time is the scheduled end time plus 14 days.

• For a recurring scheduled meeting with an end date, the expiry time is the scheduled end time of the last meeting occurrence plus 14 days.

• For an ad hoc IM or A/V conference, the expiry time is 8 hours.

• For a recurring scheduled meeting without a specified end date, the expiry time is 6 months after the last meeting activation.

In Office Communications Server, meeting expiration is controlled by processes that run on the Front End Server and the Web Conferencing Server. The processes are automatic and are based on an expiry time that is received from clients when the meeting is created. The expiration process running on the Front End Server deletes the meeting data record from the back-end database after the expiry date if the conference is not currently active. The expiry time is communicated to each conferencing server that is involved when the conference is activated. After the expiry time plus a 14-day grace period, the Web Conferencing Server deletes all conference content data (including uploaded slides, whiteboard sessions, and shared notes) from the presentation file share. This expiry period setting is configurable. For more information, see the Microsoft Office Communications Server 2007 Administration Guide.