Conferencing Servers, also known as MCUs (Multipoint Conferencing Units), are associated with a Standard Edition Server or Enterprise pool. They are software-based and collocated on a Standard Edition Server and front-end servers of an Enterprise pool in a consolidated configuration. They are installed on separate physical servers in the case of the Enterprise pool in an expanded configuration. The IM Conferencing Server and the Telephony Conferencing Server are the only exceptions. These server roles are always installed on the front-end servers, even in the Enterprise pool in the expanded configuration case.
Each of these server roles communicates directly with clients participating in a conferencing session via their own protocol, which is optimized for the media they support. These server roles also synchronize the state of the conference with a process called the focus that runs on the front-end server or Standard Edition Server. The protocol used to control the state of the conference session is called Centralized Conference Control Protocol (CCCP), also referred to as C3P. The focus sends state updates to the Conferencing Server using C3P, which the Conferencing Server listens for over an HTTPS channel.
Office Communications Server 2007 provides the following MCUs:
Each of these Conferencing Servers is described in more detail in the following sections. They share the same hardware and software requirements, which are detailed in Table 2-3.
Note
To get the most up-to-date information about Conferencing Servers, refer to http://www.microsoft.com/technet/prodtechnol/office/communicationsserver/evaluate/sysreqs/ocs-ee.mspx#EMD.
Table 2-3. Hardware and Software Requirements for Conferencing Servers
Component | Requirement |
|---|---|
Computer and processor | Dual processor, dual core with 3.0-GHz or faster processor |
Memory | 4 GB or more of RAM recommended |
Cache | 1 MB L2 per core recommended |
Hard disk | 2 SCSI hard drives with 18 GB of available hard disk space recommended |
Network | 1-GBit NIC recommended |
Operating system | Windows Server 2003 Standard Edition, Windows Server 2003 R2 Standard Edition, or higher |
Other | Active Directory directory service for Windows Server 2003 or Windows 2000 with Service Pack 3 required |
The IM Conferencing Server is automatically installed on every Standard Edition Server and every front-end server member of an Enterprise pool in both configurations (consolidated and expanded). It cannot be installed separately on a separate physical server. This service enables users to escalate a two-party IM session into a multiparty IM conference.
Escalating from a two-party IM session to a multiparty IM conference involves more than just adding new participants. New state information is involved in an IM conference, and this information must be synchronized across all the parties in an IM conference, such as tracking the roster (that is, a list of participants), determining which participants are conference leaders, displaying the participants' network of origin, as well as exposing a set of actions participants can perform (for example, mute, eject, promote, and so on).
The management of the conference session is controlled by the focus and is enforced by the IM Conferencing Server. The focus and the IM Conferencing Server communicate via the C3P protocol. Only port 5061 is required by the IM Conferencing Server.
If you use internal firewalls to compartmentalize your network, the IM Conferencing Server needs to have the same set of ports opened as the Standard Edition Server and Enterprise pool front-end server.
The Web Conferencing Server is responsible for multiplexing the Web conferencing data feed (for example, documents, application sharing, whiteboarding, and so on) from the leader to all participants in the session. Persistent Shared Object Model (PSOM) is the protocol used by the Web Conferencing Server to share documents and application content in real time to provide that collaborative experience. PSOM uses the port number 8057.
The Web Conferencing Server is collocated with the Standard Edition Server and every front-end server in an Enterprise pool in a consolidated configuration. It can also be installed on its separate physical server for higher scalability. Installing a Web Conferencing Server on its own physical server is supported only in an Enterprise pool in an expanded configuration.
Just like the IM Conferencing Server, the Web Conferencing Server hosts only Web conferences for organizers that are homed on the Standard Edition Server or Enterprise pool the Web Conferencing Server is a part of. Users homed on other Standard Edition Servers and Enterprise pools can join as participants to the Web conference, but they cannot schedule a meeting on a Web Conferencing Server that is not part of their home server. More details are covered in Chapter 5, "Conferencing Scenario."
Similar to the IM Conferencing Server and the Web Conferencing Server, the A/V Conferencing Server is an MCU for audio and video media. In the case of audio, the A/V Conferencing Server mixes the audio feeds from every participant before returning the mixed audio back to each participant. This is computationally intensive. Therefore, it is recommended that you allocate a high-end server for this purpose.
The A/V Conferencing Server uses the Real Time Audio (RTAudio) codecs for audio and Real Time Video (RTVideo) codecs for video. Both of these protocols are designed to optimize performance in high-latency, low-bandwidth networks such as the Internet. Two-way communications are peer-to-peer. Therefore, for voice calls (which make up the large majority of audio communications), the A/V Conferencing Server is not involved.
The Telephony Conferencing Server provides the functionality of joining and controlling an audio conference hosted on a Public Switched Telephone Network (PSTN) bridge from a service provider such as AT&T, Verizon, BT, Intercall, Premier, or another company. When users use the Microsoft Conferencing add-in for Microsoft Office Outlook to schedule a Live Meeting with audio or a conference call (as shown in Figure 2-9), at the time of the conference your desktop phone will be automatically set up to join the audio bridge hosted by your organization's carrier. The organizer will be able to control the audio from Communicator and perform activities such as muting everyone except the presenter, muting themselves, removing participants, and so on.
The Telephony Conferencing Server is installed automatically as part of the Standard Edition Server and also on the front-end server in an Enterprise pool. It cannot be installed separately as its own service running on a separate physical server.