Your product uses one of the following types of licenses (some products allow you to choose more than one type). It is important that you are aware of which types of licenses your company has purchased and how they are consumed. This ensures that you do not run out of licenses. The license types are:

User/Device licenses

With XenDesktop 5 Service Pack 1 or later, the license server can assign licenses to a user or a device and monitor license consumption. When assigned to a user, the license allows access from an unlimited number of devices. When assigned to a device, the license allows access from the device by an unlimited number of users.

A licensed device requires a unique device ID and is authorized for use by any individuals to access instances of XenDesktop. Use this type of license for shared devices, such as classroom, hospital, or clinical workstations.

A licensed user requires a unique user ID, such as an Active Directory entry. When assigned to a user, the license allows the user to connect to their desktops and applications with multiple devices, such as desktop computer, laptop, netbook, smartphone, or thin client. A licensed user can connect to multiple instances of XenDesktop concurrently.

The license server determines how to minimize license consumption based on the users and devices connected. The license server optimizes every 5 seconds until there are 5000 uses on distinct pairs (user/device) checked out. At 5000 uses optimization occurs every 5 minutes, which might delay status information until the next optimization.

Examples of uses on pairs:

Optimization occurs every 5 seconds for 1-4999 uses and every 5 minutes for 5000 or more uses.

5000 users * 1 device each = 5000

5000 devices * 1 user each = 5000

2500 users * 2 devices each = 5000

When users or devices connect to an application or desktop, they consume a license for the 90 day license assignment period. The assignment period begins when a connection is made, is renewed to the full 90 days during the life of the connection, and expires (allowing reassignment) 90 days after the last connection terminates. If you have to manually end a license assignment before the 90 day period elapses (for example, an employee consuming a User license leaves the company), use the udadmin command line tool.

Concurrent user licenses

This type of license is not tied to a specific user. When a user launches a product, the product requests the license and it is checked out to the specific computer or device that the user is using. When the user logs off from the session, the license is checked back in and is available for another user. Using this logic, keep the following scenarios in mind:

• Multiple sessions at different computers use multiple licenses. Each time a user launches a Citrix session from a different computer or device, a license is checked out until the user closes the session at that computer or device (at which point the license is checked back in). For example, if a user launches a session from one computer and then launches another from another computer (before closing the session on the first), two licenses are checked out.
• Because, license servers do not communicate with each other, if you are running multiple license servers you may consume more than one license (for example, with load balancing). If you are using load balancing, Citrix recommends that the product servers point to the same license server.
• Different editions consume different licenses. If a user connects to an application published on a computer running Advanced edition and then uses the same client to connect to an application published on a computer running Enterprise edition, two licenses are consumed.
• RDP connections consume a license (RDP connections to a console do not consume a license).

Concurrent system licenses

This type of license is similar to a concurrent user license; however, it is tied to a system, not a specific computer or device that the user is using.

When a user boots a computer or device and a system is launched (for example, an operating system or a virtual machine instance), a license is requested and checked out to the computer or device. The license remains in a checked out state until the system is no longer running (the computer or device is powered off or the virtual machine instance is stopped). Unlike a concurrent user license, the concurrent system license is not affected by a user logging on or off from a session; it is tied to the system’s power state (on or off).

Licenses are purchased on a per system basis; one license per running system is required.

Using this logic, keep the following scenarios in mind:

• Multiple systems running on a computer or device require one license for each system. For example, if a user is running two virtual machine instances on one computer, two concurrent system licenses are used.
• If a user is running one or more systems and logs off from a session, licenses are not released. The concurrent system license (or licenses) remains in a checked out state until the user powers off the computer or device (thereby closing the system connection to the computer or device) or stops the virtual machine instance.

Named user licenses

When a product requests a license, it is checked out to the user until a preconfigured period of time expires. This type of check-out is not tied to a computer or device; once the license is checked out, the user can run multiple sessions on different computers without checking out more licenses.