For an optimum experience when deploying Enterprise Voice, make sure that your IT infrastructure, network, and systems meet the following prerequisites:

• Communications Server 2010 Standard Edition or Enterprise Edition is installed and operational on your network.
  
  
• All edge servers are deployed and operational in your perimeter network, including Access Edge Server, Audio/Video Conferencing Edge Server, Web Conferencing Edge Server, and a reverse proxy.
  
  
• One or more users have been created and enabled for Communications Server.
  
  
• Microsoft Exchange Server 2007 Service Pack 1 (SP1) or Microsoft Exchange Server 2010 is required for integrating Exchange Unified Messaging (UM) with Communications Server and to provide rich notifications and call log information to client endpoints.
  
  
• A unique primary phone number has been designated, normalized, and copied to the msRTCSIP-line attribute for each user who is to be enabled for Enterprise Voice.
  
  

  Note:

  Communications Server supports E.164 numbers as well as non-Direct Inward Dialing (DID) numbers. Non-DID numbers can be represented in the format <E.164>;ext=<extension> or as a string of digits, with the requirement that the private extension is unique across the enterprise. For example, a private number of 1001 can be represented as +1425550100;ext=1001, or as 1001. When represented as 1001, the expectation is that this private number is unique across the enterprise.

• Administrators deploying Enterprise Voice should be members of the RTCUniversalServerAdmins group.
  
  
• At a minimum, Office Communicator 2007 is successfully deployed. To use features new to this release, Microsoft Communicator "14" is deployed.
  
  
• MKI (Managed Key Infrastructure) is deployed and configured, using either a Microsoft or a third-party certification authority (CA) infrastructure.
  
  
• Each computer on which you install Mediation Server must be:
  
  
  • A member server of a domain, and prepared forActive Directory Domain Services. For Active Directory Domain Services preparation procedures, see Preparing Active Directory Domain Services for Communications Server 2010.
    
    
  • Running one of the following operating systems:
    
    
    • The 64-bit edition of the Windows Server 2008 Standard operating system
      
      
    • The 64-bit edition of the Windows Server 2008 Enterprise operating system
      
      
• If the connection to the PSTN or PBX is by means of a Time Division Multiplexing (TDM) connection, one or more media gateways are available for deployment. (If the connection is by means of a SIP trunk, a media gateway is not required.)
  
  

If there is an outage, disruption, or other degradation of the power, network, or telephone services at your location, the voice, instant messaging, presence, and other features of Communications Server and any device connected to Communications Server may not work properly.

Voice communications with Communications Server depend upon the availability of the server software and the proper functioning of the voice clients or the hardware phone devices connecting to the server software.

For those locations where you install a voice client (for example, a PC running Communicator "14" or an Microsoft Communicator “14” Phone Edition device), it is recommended that you maintain a backup option for users to call emergency services (for example, 911, 999, and so on) in case of a power failure, network connectivity degradation, telephone service outage, or other problem that may inhibit operation of Communications Server, Communicator "14", or the Phone Edition devices. Such alternative options could include a telephone connected to a standard public switched telephone network (PSTN) line or a cell phone.

Please note that the use of a multi-line telephone system (MLTS) may be subject to U.S. (that is, state and/or federal) and foreign MLTS laws that require the MLTS to provide a callers telephone number, extension, and/or physical location to applicable emergency services when a caller makes a call to emergency services (for example, when dialing an emergency access number such as 911 or 999).In this release, Microsoft Communications Server 2010 can be configured to provide a caller’s physical location to an emergency services provider, as described in Emergency Services (E9-1-1). Compliance with MLTS laws is the sole responsibility of the purchaser of Microsoft Communications Server 2010, Microsoft Communicator "14", and Microsoft Communicator “14” Phone Editiondevices.