The software requirements for deployment of the three server roles for Office Communications Server 2007 R2 for the deployment in this walkthrough are shown below:

• The 64-bit edition of Windows Server 2008 Standard, Enterprise or Datacenter
  
  
• Office Communications Server 2007 R2
  
  

The following operating system updates are prerequisites for deploying Office Communications Server 2007 R2:

• Microsoft Knowledge Base article 953582, "You may be unable to install a program that tries to register extensions under the IQueryForm registry entry in Windows Server 2008 or in Windows Vista," at http://go.microsoft.com/fwlink/?LinkId=131392 . This update must be installed before you install Office Communications Server 2007 R2 Administrative Tools in the following situations only:
  
  
  • On computers that are running the Windows Vista operating system, if you also install Remote Server Administration Tools (RSAT)
    
    
  • On computers running Windows Server 2008, if Active Directory Domain Services (AD DS) administrative tools are installed
    
    
• Microsoft Knowledge Base article 953990, “AV at mscorwks!SetAsyncResultProperties,” at http://go.microsoft.com/fwlink/?LinkId=131394 .
  
  
• Microsoft Knowledge Base article 967674, “Description of the update package for Communications Server 2007 R2, Unified Communications Managed API 2.0 Core Redist 64-bit: April 2009,” at http://go.microsoft.com/fwlink/?LinkId=157761 .
  
  
• Microsoft Knowledge Base article 967827, “Description of the update package for Communications Server 2007 R2, Core Components: April 2009,” at http://go.microsoft.com/fwlink/?LinkID=157762 .
  
  

The following components are also required. If you do not have them, Setup will automatically install them for you.

• Microsoft .NET Framework 3.5 (64-bit)
  
  
• Microsoft Visual C++ 2008 redistributable