All Citrix products utilize a common licensing service. This service can run on a dedicated system or it can be hosted on a system that performs other roles. In small environments, licensing might be installed on the first controller using the default installation options. In mid-sized to large enterprise environments, it is recommended that you have a dedicated license server.
All Citrix products will check with the license server on startup and user login to ensure the product is properly licensed and there are enough user licenses available. A single license server can support up to 10,000 continuous connections.
The Citrix products for use in our environment, such as XenApp and Provisioning Server, store a replica of the licensing information, including the number and type of licenses. If a server loses its connection to the license server, the product enters a grace period and uses its local record of the licenses...