How It Works Server-based model. The client is merely a display and input device. All computation is done centrally on the server, and all data is stored in a data center. Nothing is executed or persistent on the client. Users connect remotely to a shared session on a server operating system. Best Suited For Environments where a critical business application is needed by users across a broad spectrum of the user base, and application compatibility and operating system support may be a challenge. IT can provide the application as a service without needing testing to ensure compatibility across all platforms and operating systems. Examples: enterprise customer relationship management, finance, and human resources applications. Endpoint Considerations This delivery model can be used both with thin clients and intelligent clients. Thin clients are most appropriate when users don’t need to be mobile; when no user personalization is needed or it can easily be removed by reimaging; and when applications being accessed are not computing- or graphics-intensive. Intelligent clients are necessary when the user needs to use applications outside of the terminal services session. Terminal services sessions are not meant to host desktop applications since they run server operating systems.
Before making the thin or intelligent client decision, take into account what type of applications and content users will require not just today, but also two to three years into the future. Benefits Security: The operating system, applications, and data never leave the data center. Manageability: Applications and data are centralized for simpler administration, application management, validation and support, and more reliable backup; user adds, moves, and changes are simple. Costs: There is a lower cost of incremental software deployment. Access: Users can access applications from any network-connected client. Disaster recovery and business continuity: Users can shift to another client or site. Limitations Performance: Performance degrades as the number of users per server increases; there can be graphics bottlenecks; the model requires a continuous stream of low-latency bandwidth to maintain display, keyboard, and mouse responsiveness. Software compatibility: Not all software or specialized peripherals are compatible or suited to this approach. Mobility: This model requires a persistent network connection with adequate bandwidth.
Costs: New deployments are expensive, including space, servers, software, and networking. Disaster recovery and business continuity: If server function is lost, processing must shift to a redundant server or data center; loss of network function renders clients inoperable. User satisfaction: This approach does not provide a PC-like experience in performance, customization, flexibility, and mobility.
Virtual Hosted Desktops
How It Works Server-based model. The virtual hosted desktops (VHD) model, sometimes called virtual desktop infrastructure (VDI), is similar to terminal services in that all computation and storage is centralized. But with VHD, users have their own complete virtual machine and customized desktop, including the operating system, applications, and settings. To improve the user experience, most VDI protocols have the ability to offload some computing tasks to the client. Best Suited For Environments where users have an entire desktop image that needs to be accessed from multiple locations—and the operating system, applications, and workload of that image are stable and predictable. (Requirements need to be well understood to prevent overloading servers.) Example: You need to deliver desktop images to remote, international software developers who work with data and IP that absolutely cannot leave the country of origin.
Intel IT Center Planning Guide | Desktop Virtualization