This  report is part of a larger series of Directions on Microsoft TeleBriefings and should be used in connection with the Directions on Microsoft Licensing Outlines.

A Virtual Desktop Infrastructure (VDI) allows a user's desktops and applications to run in a private virtual machine hosted on servers in a data center rather than locally on the user's PCs. Though technically complex and not inexpensive, VDI has sparked considerable interest because it allows users to access personalized desktops from any client; and can simplify provisioning, updating, and decommissioning of desktop environments.

Licensing a VDI using Microsoft technologies is complex because it involves multiple software layers, most licensed separately, and numerous licensing options and choices, each with their own set of advantages and drawbacks.

In this TeleBriefing, Research Chair Rob Horwitz explains the six different software layers customers need to license, their role in VDI, what licensing choices they have, and how to choose. Though the presentation will focus on licensing the Microsoft VDI technology stack, the presentation will be relevant to customers combining Microsoft technologies with offerings from VMWare and Citrix.

Defining Virtual Desktop Infrastructure (VDI)

• Client Architecture
• Desktop functions as terminal
• Datacenter Architecture
• Lots of parts / layers; most licensed separately

Overview of subscription-based licenses associated with VDI

• SA = Software Assurance
• VECD = Virtual Enterprise Centralized Desktop
• VDI Suites
• MDOP = Microsoft Desktop Optimization Pack (includes App-V)

The Six Software Layers You Have to License: An Overview

• Maps architecture to licensing layers

Layer 1: Hypervisor

• Role in VDI: Hosts the virtual machines (VMs) on a server
• Licensing choices: Windows Server 2008 R2 Standard / Enterprise; Hyper-V Server
• Considerations for choosing

Layer 2: Base Windows Server Services

• Role in VDI: Authentication, user settings, etc.
• Licensing choices: Windows Server 2008 Client Access License (CAL) per user or per device
• Considerations for choosing

Layer 3: Windows Client OSs

• Role in VDI: OSs that are running in the VMs
• Licensing choices: VECD or retail OS
• Considerations for choosing

Layer 4: Connection Broker and Gateway

• Role in VDI: Route users to their personal VM
• Licensing choices: VDI Suites or Remote Desktop Services (RDS) CAL
• Considerations for choosing

Layer 5: System Center (SC) Management Tools

• Role in VDI: Provision VMs, monitor servers, etc.
• Licensing choices: VDI Suites or licensing System Center on its own
• Considerations for choosing

Layer 6: App-V

• Role in VDI: Deploy applications into VMs
• Licensing choices: MDOP along or bundled in VDI Suite
• Considerations for choosing

VDI: Full Meal Scenario

• Licensing scenario illustrated, complete with prices