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

• Lync 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 Edge Servers with Access Edge service, A/V Edge service, Web Conferencing Edge service, and a reverse proxy.
  
  
• One or more users have been created and enabled for Lync Server.
  
  
• Microsoft Exchange Server 2007 Service Pack 1 (SP1) or latest service pack, or Microsoft Exchange Server 2010 is required for integrating Exchange Unified Messaging (UM) with Lync 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:

  Lync Server supports E.164 numbers and 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 Lync 2010 is deployed.
  
  
• Managed key infrastructure (MKI) 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 for Active Directory Domain Services (AD DS). For Active Directory Domain Services (AD DS) preparation procedures, see Preparing Active Directory Domain Services for Lync Server 2010 in the Deployment documentation.
    
    
  • 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 PSTN gateways are available for deployment. (If the connection is by means of a SIP trunk, a PSTN 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 Lync Server and any device connected to Lync Server may not work properly.

Voice communications with Lync 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 Lync 2010 or an Microsoft Lync 2010 Phone Edition device), we recommend that you maintain a backup option for users to call emergency services (for example, 911 or 999) in case of a power failure, network connectivity degradation, telephone service outage, or other issue that may inhibit operation of Lync Server, Lync 2010, 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.

The use of a multiline telephone system (MLTS) may be subject to U.Sstate or federal laws or the laws of other countries that require the MLTS to provide a caller’s telephone number, extension, and/or physical location to applicable emergency services when a caller is placed to emergency services (for example, when dialing an emergency access number such as 911 or 999). In this release, Microsoft Lync 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 Lync Server 2010, Microsoft Lync 2010, and Microsoft Lync 2010 Phone Edition devices.