User Layer
The top layer of the design methodology is the user layer, which is defined for each unique user group.
The user layer appropriately sets the overall direction for each user group’s virtualized environment. This layer incorporates the assessment criteria for business priorities and user group requirements in order to define effective strategies for endpoints and Citrix Receiver. These design decisions impact the flexibility and functionality for each user group.
Endpoint Selection
There are a variety of endpoints devices available, all with differing capabilities, including:
• Tablet based on Android or iOS
• Laptop
• Desktop PC
• Thin client
• Smartphone
The user’s primary endpoint device must align with the overall business drivers as well as each user’s role and associated requirements. In many circumstances, multiple endpoints may be suitable, each offering differing capabilities.
Decision: Endpoint Ownership
and managed. However, more and more organizations are now introducing bring your own device (BYOD) programs to improve employee satisfaction, reduce costs and to simplify device management. Even if BYOD is a business priority, it does not mean that every user should be allowed to use a personal device in the corporate environment.
Certain user requirements, which were identified during the user segmentation, can greatly impact the suitability of personal devices:
• Security – Users requiring a high-level of security might not be able to bring a personal device into the secured environment for risk of data theft.
• Mobility – Users operating in a disconnected mode might not be able to use a personal device, as the local VM FlexCast model associated with this type of requirement can have specific hardware requirements, or special maintenance requirements. Additionally, the local operating system may be destroyed when the local VM FlexCast option is utilized.
• Criticality – Users with a high criticality rating might require redundant endpoints in the event of failure. This would require the user to have an alternative means for connecting in the event their personal device fails, likely making these users poor candidates for a BYOD program.
• FlexCast model – A personal device should not be recommended for user groups utilizing a client-hosted FlexCast model like streamed VHD, local VM or Remote PC. These FlexCast models typically require a specific hardware configuration or installation that will restrict device selection.
The diagram shown below provides guidance on when user owned devices could be used.
Decision: Endpoint Lifecycle
Organizations may choose to repurpose devices in order to extend refresh cycles or to provide overflow capacity for contract workers. Endpoints now offer more capabilities allowing them to have longer useful lifespans. In many cases, these hardware capabilities vastly outstrip the needs of a typical user. When coupled with the ability to virtualize application and desktop workloads, this provides new options to administrators such as repurposing existing workstations. These options go well beyond the simple threeyear PC refresh cycle. However, the benefits of repurposing or reallocating a workstation should be balanced against the following considerations.
• Minimum standards – While cost factors of repurposing existing workstations may be compelling, certain minimum standards should be met to guarantee a good user experience. At a minimum, it is recommended that repurposed workstations have a 1GHz processor, 1GB of RAM, 16GB of free disk space and a GPU that is capable of supporting HDX features.
• Business drivers – Priorities underpin the success of any major project. Those organizations that have prioritized reducing capital expenditure by means of prolonging the hardware refresh cycle can benefit from repurposing hardware. Conversely, if an organization’s business drivers include reducing power consumption as part of an overall green initiative, purchasing newer endpoints may be beneficial in order to take advantage of the latest generation of power management capabilities available in the most modern devices.
• Workload – The type of work and FlexCast model for an end user can determine whether they are a good candidate for a repurposed endpoint, or may be better served with a new device. If the work performed by the individual involves locally installed applications, the individual may be best served by a new endpoint that offers the most powerful and recently updated processor and graphics architecture. However, if a user is largely performing tasks associated with virtualized applications that do not involve the latest multimedia capabilities such as webcams, VoIP and media redirection, then a repurposed workstation should be a viable alternative.
Decision: Endpoint Form Factor
The capabilities of endpoints have grown along with efficiencies offered in thin client form factors. Even mid-range thin clients now have graphics capabilities that allow utilization of HDX features such as multi-monitor support while offering management and power efficiency benefits. This expansion of capabilities has given IT administrators more options and flexibility than ever before.
Most organizations will likely deploy a mixture of fully featured clients as well as thin clients. It is important to focus on multiple user group attributed in order to best determine the type of endpoint that should be deployed:
Decision: Thin Client Selection
Thin client vendors now offer a range of operating system choices, including Windows Thin PC (based on Windows 7), embedded versions of Windows (XP, Windows 7 and Windows 8), Linux
variants, as well as limited functionality clients that boot directly into a virtual desktop and offer a zero operating system footprint. The following factors should be considered during the selection of a thin-client device:
• User workload – Windows Thin PC or limited functionality solutions such as Dell Wyse Zero clients should be tailored to true task workers or knowledge workers with limited needs. More
capable thin devices such as Windows Embedded solutions can be provided to users that require
• In-house expertise – Many organizations have management toolsets already in place to handle thin client infrastructure such as retailers that may have kiosks. In-house expertise with a thin client management infrastructure can determine the selection of thin client platform. It is recommended that existing in-house expertise is leveraged, so long as the platform is capable of supporting a virtual desktop infrastructure implementation, as outlined on the Citrix Ready site.
• Licensing cost – There are licensing considerations for most platforms. Windows thin PC and embedded versions incur immediate license costs related to Microsoft licensing, whereas a custom Linux solution may not. However, these costs must be closely balanced against additional add-on licensing that may be required for Linux devices, which are built into Windows. For example, various media codecs may require additional license expenditure in a Linux thin client context. For more information, please refer to the Microsoft Partner Site.
Experience from the Field
Large systems integrator – A large systems integrator recommended that a customer deploy a single type of low-end, limited capability endpoint for all users. Upon deployment to production, users immediately complained that they received a poor user experience when viewing multimedia content over the WAN. At great cost, the systems integrator and customer re-assessed the environment and chose to deploy endpoints that supported HDX MediaStream. The mistake caused a schism between systems integrator and the customer, resulting in lost time, capital and the end of a business relationship that was fostered over many years. It is critical that the endpoints assigned to each user group can support their requirements.
