Solve the mystery of VDI licensing

A VDI deployment is tricky enough without worrying about having the right VDI licensing. Stay one step ahead of the problems by knowing which license to use.

Finding the right VDI licenses to fit a deployment's needs does not have to be as complicated as Prince Charming finding the right foot to fit the glass slipper on.

Licensing in a virtual desktop deployment gets tricky because the traditional structure of desktop licensing no longer works. In the past, a user had one device he or she worked on. IT would get a license to cover that device, and everyone lived happily ever after.

In a VDI deployment, the virtual desktops are not limited to a specific device or user. If an organization wants multiple users to work with the same devices, IT must buy licenses per device. If an organization wants to have one employee who can work on multiple devices, IT must buy licenses per user.

Explore the ways VMware and Citrix handle licenses in their VDI products and uncover the tricks of licensing virtual desktops with Windows 10.

VDI licensing for VMware Horizon 7

VMware offers two types of VDI licenses for Horizon 7: per Named User (NU) and per Concurrent Connection (CCU). Horizon 7 offers several different editions, including Horizon for Linux, Horizon Standard, Horizon Advanced and Horizon Enterprise. Each edition comes with different features, capabilities and licensing options.

The per Named User licensing model is as straightforward as the name sounds. Each VDI license applies directly to a user, giving him or her access to a virtual desktop on any compatible device. The per-Named User licensing works well for organizations with dedicated employees who use virtual desktops for their jobs.

CCU licensing is similar to a per-device license. The license covers a single device that multiple employees use to access a virtual desktop. CCU licensing is best suited for organizations with numerous employees who share a single device, such as a hospital.

The licensing choice is ultimately up to the organization, except when it comes to Horizon Standard Edition. In this edition of Horizon, the only VDI licenses available are CCU licenses. On the plus side, the license applies to all the features within Horizon View Standard, such as the Blast Extreme protocol for graphics-intensive workloads.

Citrix is unique in that it does not allow IT to manually assign licenses to each user/device.

Horizon Advanced and Horizon Enterprise offer both options to organizations, as well as many more features that are covered under the license. Horizon Standard starts at $3,116 per Named User license. Horizon Advanced begins at $3,116 for a package of 10 Named User licenses or $4,979 for a package of 10 CCU licenses. VMware Horizon Enterprise Edition starts at $4,362 for a package of 10 named user licenses, or $7,169 for 10 CCU licenses.

VDI licensing for Citrix Virtual Apps and Desktops

Citrix has two general types of VDI licensing: product licensing and volume licensing. Volume licensing provides discounts and ease of use for larger organizations or public sector organizations, such as schools and governments. The commercial sector divides into two different types of licenses: an enterprise license agreement for 250 users and Easy licenses for five or more users on an as-needed basis.

Product licensing, which is for each specific Citrix product and the end-user licensing agreement, breaks down into user/device licensing and concurrent licensing. The user/device licensing covers one user for all devices he or she uses Citrix products on. This works well for most companies because employees can access their personal virtual desktops from any device.

Similarly, per device licensing licenses a specific device, without regard to the user who is using the device. The concurrent licensing is not tied to specific users or to specific devices. It allows for optimal license flexibility since any user can work from any device, so long as the concurrent license count is not exceeded.

Citrix is unique in that it does not allow IT to manually assign licenses to each user/device. Citrix uses a licensing server to assure licensing agreements match the type of license assigned to each user and endpoint device. If VDI licenses go unused for 90 days, the licensing server eventually reclaims a terminated user/device license for a new employee. This can get tricky for organizations with a fluctuating number of employees.

VDI licensing for Windows virtual desktops

Organizations that wish to run on-premises Windows virtual desktops must also make sure they have the correct desktop OS licensing. Licensing for Windows 10 Enterprise falls under Microsoft's Volume Licensing program, where organizations must make the decision between Microsoft Software Assurance (SA) and Windows Virtual Desktop Access (VDA). Microsoft only offers SA to certain types of Volume Licensing programs, making VDA a great alternative that offers similar SA benefits but is specifically focused on Windows 10 virtual desktop user access.

Windows 10 licensing also comes down to a per-device or per-user approach. Per user offers employees greater mobility and flexibility to create their own workplaces. Per device is the traditional Windows licensing approach but requires IT to license every single device users will work with. A perk to per-device licensing is that the virtual desktop can run Windows 10 Pro or earlier versions with VDI and is not tied to Windows 10 Enterprise.

VDA-based per-device licenses also give users Roaming Use Rights, meaning that the primary user of a device may access licensed desktops on nonlicensed devices (such as a user-owned device) -- with restrictions. Both per-user and per-device licensing grant users access to up to four instances of Windows 10 virtual desktops.

Both SA and VDA run per-user and per-device licensing, but there is a big difference between the two for per-user licenses. SA requires IT to license a user's primary device for Windows 10 and be the main user of the device. VDA does not have any such requirements, making it extremely appealing for multiple users. VDA licensing is also the only option for accessing a Windows virtual desktop from a thin client device, as VDA acts as the client access license for the virtual desktop.

Just as it is possible to host a Windows 10 virtual desktop on a Citrix or VMware platform, Microsoft offers a Windows Server-based VDI hosting product. Historically, licensing a Windows Server-based VDI platform was a complex undertaking due to the need to license the various individual components such as hypervisor, connection broker, etc. In March 2019, however, Microsoft greatly simplified the process by introducing two new single license models -- the Microsoft Virtual Desktop Infrastructure Standard Suite and the Microsoft Virtual Desktop Infrastructure Premium Suite.

Both suites are sold as a subscription and licensed on a per client device basis. Licensing for the VDI Standard Suite starts at $21 per client device, per year. Both the Standard and Premium suites support virtual machine-based virtual desktops. The VDI Premium Suite adds the ability to host session-based virtual desktops and virtualized applications.

With the release of Windows Virtual Desktop for Azure in March 2019, Microsoft also made it possible to host virtual desktops in the Azure cloud. As is usually the case, licensing works differently in the Azure cloud than it does on premises.

VDI licensing for Office 365

When an organization purchases a Microsoft 365 subscription, formerly Office 365, the subscription is licensed on a per-user basis. As such, each user receives product use rights for the Office applications (Word, Excel, PowerPoint, etc.). The license allows each user to install these applications -- which are often referred to as the Microsoft Office Professional Plus applications -- on up to five devices.

This licensing model is not well suited for VDI environments, because most VDI environments are non-persistent. In a non-persistent VDI environment, a collection of host servers maintains a collection of virtual desktops, each of which runs within a virtual machine.

When a user logs in, a connection broker assigns the user a virtual machine from the pool of available virtual desktops. When the user's session ends, that virtual desktop is reset to a pristine state and returned to the pool. This means that the user does not have ownership over any one specific virtual desktop. As such, Office 365 licensing models that tie application installation to the user simply do not work.

Organizations using the Microsoft Office Professional Plus applications in a non-persistent VDI environment must adopt the same licensing model that Microsoft uses for shared computers. In a shared computer model, Microsoft Office Professional Plus is licensed on a per device basis rather than being licensed to the individual user.

The advantage to using this application delivery model is that because non-persistent virtual desktops must be licensed on a per device basis, the Office applications that are installed on a virtual desktop do not count against the number of Office instances that a user is able to install -- assuming that the user has the necessary per-user license.