Corporate Background Four Thin Client Virtualization Models

Corporate Background

Four Thin Client Virtualization Models

Info-Tech sees increased interest in thin client deployments as the technology that supports the back end evolves with virtualization. With more options than ever before, understanding the technology is essential to choosing the right solution to suit enterprise needs.

Inside this report:

Info-Tech's products and services Introduction…………….……………………………………………………………...... 2 combine actionable insight and relevant advice with ready-to-use Choose Your Flavor...... …………………………..3 tools and templates that cover the full spectrum of IT concerns. Our practical approach is designed to Application Streaming...... …………………………..3 have a clear and measurable positive impact on your organization's bottom line. Application/OS Streaming...... …………………………..3

We serve over 21,000 clients at Virtual Desktop Infrastructure (VDI)...... …………………………..4 8,000 organizations around the world. Since 1998, we have focused on making the work of IT Application/OS Provisioning...... …………………………..4 professionals easier - and on helping them achieve greater Key Takeaways...... ……………………………………...... 4 personal and corporate success. Bottom Line....……………………………………………………………..…………....5 www.infotech.com

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Introduction

Virtualization technology is driving new interest in thin client implementations. There are four different ways in which virtualization works with thin client deployment:

1. Application Streaming 2. Application and Operating System Streaming 3. Virtual Desktop Infrastructure (VDI) 4. Application/OS Provisioning

As virtualization technology evolves, enterprises should explore the new options that are available and understand how the different choices interact with thin client deployment.

Choose Your Flavor

Streaming technology is represented by products such as Citrix Presentation Server (XenApp), Microsoft SoftGrid, and VMware Thinstall. It can be divided into two categories: application-only streaming and combined application/OS streaming..

Application Streaming

Applications are hosted on a separate server and are streamed to individual client terminals. Each time an end user logs on the applications are dynamically streamed to the terminal. With a streaming approach, latency is minimal since everything is running on the client terminal once it has been loaded from the server. Note that in this approach, the client terminal needs to host an operating system that can run the streamed application. Managing these distributed operating systems can increase complexity and cost of the thin client solution. There is little difference between this and managing OSes across distributed “fat client” PCs.

However, one of the goals of thin client deployment is moving all of the processing to the servers. For application-only streaming, there still has to be some processing power on the thin terminal to support a local operating system and application. In addition, the local OS must be managed separately from the applications; patches and other updates must be distributed to the individual machines.

Application/OS Streaming

In this case, both the applications and OS are hosted on a separate server and are streamed to the individual client terminals. When the clients are turned on, the terminal configurations will tell the server which applications/OS should stream to which terminal. As opposed to application-only streaming, all applications and OSes are maintained at a central location; any updates or patches are applied at the server end.

With combined streaming, the OS is streamed with the applications, so the terminal doesn’t have to support any local software. The preboot execution environment (PXE) is configured so that the OS and applications are streamed to the thin client or PC during

3 © 1998-2008 Info-Tech Research Group Four Thin Client Virtualization Models startup. However, the terminal still requires enough memory, processing, and video horsepower to run the streamed OS/Apps instance.

Virtual Desktop Infrastructure (VDI)

With the VDI model, all processing runs on the server side. Individual virtual machines are hosted on a server such as VMware’s ESX server. Users can access a full PC environment configured to their requirements by accessing the server via Remote Desktop Protocol (RDP). The advantage of VDI is that the user has access to a complete Windows desktop while all virtual machine instances can be managed on centralized infrastructure. The end user device can be a very simple, inexpensive thin client device. All user input is sent back to the remote virtual machine for processing and all graphic and screen images are transmitted to the user terminal over the network. Some latency issues may be experienced depending on the available bandwidth.

Application/OS Provisioning

It’s important to understand that the different types of virtualization outlined above are not mutually exclusive. Perhaps the most interesting of the four approaches has been pioneered by Citrix. It combines VDI with application and OS streaming to create a virtualization hybrid. While the applications are normally streamed to the server hosting the virtual instances, they can also be configured to stream to individual users and bypass the host server.

With Citrix XenDesktop, thin terminals have access to individually configured virtual machines (VMs); however, the applications and OSes are all maintained on a server that is separate from the server hosting the VMs. This application/OS server then provisions the VM server with the applications it requests. The provisioning server can also provide services directly to the client terminals, including regular “fat” desktops.

Key Takeaways

1. Understand the virtualization eco-system. Virtual PCs and application streaming are both gaining ground. In understanding how these work, it’s important to understand that

4 © 1998-2008 Info-Tech Research Group Four Thin Client Virtualization Models they’re not mutually exclusive. Application provisioning leverages both technologies to incorporate the ease of management of application streaming and the user friendliness of VDI.

2. Desktop virtualization not limited to thin clients. These technologies can be used with regular old fat clients as well. This allows for a heterogeneous environment where user groups can be defined by their level of access and still use the same back-end technology.

3. Infrastructure dictates deployment. With VDI deployments, bandwidth is a consideration. Enterprises that have spotty or limited connectivity will experience higher latency.

4. Vendors are hedging their bets. Although VDI has shown a slight edge over streaming technology, it’s not a runaway lead. Vendors are moving away from a single virtualization solution. With Citrix’s acquisition of XenSource and VMware’s acquisition of Thinstall, both vendors expanded their product set to include streaming technology.

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