Note: This article is based on RDS 2008 (R2) and might not apply to RDS 2012 (R2)
 
This is a landing page for articles about how to license Remote Desktop Services in WS08 R2. It contains links to articles on topics such as (but not limited to):
  • The RDS Licensing Model
  • Planning RDS Licensing
  • Configuring the license type on RD Session Host servers
  • Deploying the RD Licensing Server
  • Managing RDSCALs

The RDS Licensing Model

Planning RDS Licensing

Configuring the Licensing Model on RD Session Host servers

Deploying RD Licensing Servers

Step by Step guide on Deploying Remote Desktop Licensing

The goal of RD Licensing is to manage the Remote Desktop Services client access licenses (RDS CALs) that are required for each device or user to connect to an RD Session Host server. You use RD Licensing to install, issue, and track the availability of RDS CALs on a Remote Desktop license server. These steps explain deploying Remote Desktop Licensing in great detail.

Step 1: Setting Up the Contoso Domain
Step 2: Activating the Remote Desktop License Server
Step 3: Installing Remote Desktop Services Client Access Licenses (RDS CALs) on the Remote Desktop License Server
Step 4: Configuring the RD Session Host Server to Support RD Licensing
Step 5: Configuring the RD Connection Broker Server to Support RD Licensing
Step 6: Verifying RD Licensing Functionality
Appendix A: Rebuild the RD Licensing Database

Managing RDSCALs

Migrating CAL's  :  On a Windows Server 2008 R2 RD Licensing Server, you can migrate / move RD CAL's from one server to another server.  Full instructions at : http://technet.microsoft.com/en-us/library/dd851844.aspx

CAL requirements including VDA

Best article that indicates when VDA as well as RDS CAL is required (if running a Server SKU as a VM based VDI desktop) is here