Enterprise Voice integrates voice with other messaging media, such that when an incoming call arrives at the server, the server maps the number to the user’s SIP-URI and then forks the call to all the client endpoints associated with that SIP-URI. This process requires that each user be associated with a primary phone number.

A primary phone number must be:

• Globally unique or, in the case of internal extensions, unique in the enterprise.
  
  
• Owned by and routable in the enterprise. Personal numbers should not be used.
  
  

Enterprise users can have two or more telephone numbers listed for them in Active Directory Domain Services (AD DS). All the telephone numbers associated with a particular user can be viewed or changed on the property sheet for that user in the Active Directory Users and Computers snap-in.

The Telephone number box on the General tab of the User Properties dialog box should contain the user’s main work number. This number will usually be designated as the user's Primary Phone Number.

Some users may have special requirements (for example, an executive who wants all incoming calls routed through an administrative assistant), but such exceptions should be limited only to those where the need is clear and critical.

After a primary number is chosen, it must be:

• Normalized to E.164 format, wherever possible.
  
  
• Copied to the Active Directory msRTCSIP-line attribute.
  
  

  Note:

  Coexisting with remote call control (RCC) RCC is the ability to use Office Communicator to monitor and control a desktop PBX phone. Control is routed through the server, which acts as a gateway to the PBX. RCC first became available with Live Communications Server 2005 with Service Pack 1 (SP1) and Communicator 1.0. Office Communications Server 2007 R2 and Office Communicator 2007 R2 together continue to provide RCC to users who are not enabled for Enterprise Voice. If you have enabled RCC in your organization, you know that RCC also uses the msRTCSIP-line attribute to designate the primary phone number for users. If your organization will have some users enabled for Enterprise Voice and others, perhaps most, still connected to a PBX, you may be concerned about whether Enterprise Voice and RCC can coexist.

There are three methods for populating the msRTCSIP-line attribute:

• Microsoft Identity Integration Server (recommended)
  
  
• The Users page in the Communications Server Control Panel
  
  

Where many phone numbers must be processed, a script is the obvious choice. Depending on how your organization represents telephone numbers in Active Directory Domain Services, the script may have to normalize primary phone numbers to E.164 format before copying them to the msRTCSIP-line attribute.

• If your organization maintains all telephone numbers in Active Directory Domain Services in a single format, and if that format is E.164, your script only needs to write each Primary Telephone Number to the msRTCSIP-line attribute.
  
  
• If your organization maintains all telephone numbers in Active Directory Domain Services in a single format, but that format is not E.164, your script should define an appropriate normalization rule to convert Primary Telephone Numbers from their existing format to E.164 before writing them to the msRTCSIP-line attribute.
  
  
• If your organization does not enforce a standard format for telephone numbers in Active Directory Domain Services, your script should define appropriate normalization rules to convert Primary Phone Numbers from their various formats to E.164 compliance before writing the Primary Telephone Numbers to the msRTCSIP-line attribute.
  
  

Your script will also have to insert the prefix Tel: before each primary number before writing it to the msRTCSIP-line attribute.

The expected format of the number specified in this attribute is:

• Tel:+14255550100;ext=50100.
  
  
• Tel:5550100 (for unique enterprise wide extensions)
  
  

  Important:
  The normalization performed by the Address Book Service (ABS) does not replace or otherwise eliminate the need to normalize each user's primary phone number in Active Directory Domain Services because ABS does not have access to Active Directory Domain Services and therefore cannot copy primary numbers to the msRTCSIP-line attribute.

Other than identifying which users are to be enabled, no special planning is required to complete this step.

Users who are enabled for Enterprise Voice will not be able to make calls to the PSTN without dial plans in place. A dial plan is a named set of normalization rules that translates phone numbers for a named location, individual user, or contact object into a single standard (E.164) format for purposes of phone authorization and call routing. Normalization rules define how phone numbers expressed in various formats are to be routed for each specified location, user, or contact object.

For information about preparing dial plans, see Dial Plans and Normalization Rules.

User class-of-service settings on a legacy PBX, such as the right to make long-distance or international calls from company phones, must be reconfigured as VoIP policies for users moved to Enterprise Voice. For details about planning and creating policies for Enterprise Voice, see Voice Policies.

Call routes specify how Communications Server 2010 handles outbound calls placed by Enterprise Voice users. When a user dials a number, the server, if necessary, normalizes the dial string to E.164 format and attempts to match it to a SIP URI. If the server is unable to make the match, it applies outgoing call routing logic based on the number. The final step in defining that logic is creating a separate named call route for each set of target phone numbers that are listed in each dial plan.

For details about planning call routes, see Voice Routes.

Users who formerly were hosted on a traditional PBX or on a SIP Trunk connection to an Internet Telephony Service Provider (ITSP) retain their phone numbers after the move. The only requirement is that after the move, the PBX or SIP Trunk must be reconfigured to route incoming calls for Enterprise Voice users to the media gateway or the Mediation Server that connects to the Communications Server 2010infrastructure. Contact your PBX vendor or ITSP for details about how to configure dual forking.

Moving users to Exchange Unified Messaging consists of the following tasks:

• Configure Exchange Unified Messaging and Communications Server to work together.
  
  
• Enable users for Exchange Unified Messaging call answering and Outlook Voice Access. This task is performed on the Exchange Unified Messaging server. For details, see the Exchange Server 2007 product documentation at http://go.microsoft.com/fwlink/?LinkID=139372.