XenDesktop Planning Guide: User Bandwidth Requirements
Regardless of the flavor of virtual desktop being implemented (hosted shared, hosted VM-based VDI, local streamed, etc.), the network plays a critical role, especially for remote and branch office users. If the network bandwidth is not planned properly, users will most likely experience poor performance with their virtual desktop. When planning a virtual desktop solution, one must think about how the user’s workload will evolve. The design must be able to support future activities, not just today’s. As can be observed, the content users interact with is changing from textual-based to more multimedia-based. Any solution and methodology must be able to account for these changes in user behavior. Although there is no single answer to the question of how much bandwidth will a user need, this planning guide provides recommendations on how to estimate the user network requirements. This guide is used to provide bandwidth estimates during the planning and design phase. Actual results may vary during implementation due to user habits, bandwidth utilization, and infrastructure implementation. This methodology provides an average bandwidth estimate. Different activities will result in a burst of traffic (video and printing). It is assumed traffic bursts will be random between users throughout the workday. If all users have network bursts at the same time, performance will degrade as adequate bandwidth levels will not be available. The bandwidth estimates were obtained through the testing procedures identified in the CTX124457 – Performance Assessment and Bandwidth Analysis for Delivering XenDesktop to Branch Offices white paper. Additional modifications, as explained in CTX125060 - Best Practices for Optimizing HDX Technologies white paper, can be used to further reduce bandwidth consumption at the cost of the user experience.
As one would expect, the user experience can degrade as the latency increases and the bandwidth decreases. Proper network planning must be based on the type of work users are performing and the overall network topology. The bandwidth requirements of delivering a full Windows desktop will likely be higher than the bandwidth required for delivering few applications using a solution like XenApp because a full Windows desktop provides a richer experience along with more multimedia and graphical content and is idle less often than when a user is only accessing few applications. Estimating network requirements needs planning and following best practices because Citrix HDX technology tunes itself based on several factors including the servers, end points and the amount of network bandwidth available. For example, if less bandwidth is available then more compression is applied. Page 2
Also, to better determine user bandwidth requirements, the user’s activity must be assessed. Simply estimating bandwidth for Office-based applications will result in inadequate performance if users also print and access multimedia content. The percentage of time a user spends working with Office-based applications, browsing the Internet, accessing videos, and being idle will help in determining the overall bandwidth required.
By calculating the percentage of time a user is expected to be doing certain activities, a rough estimate can be determined for HDX bandwidth requirements, which is shown in the follow table: Parameter (medium workloads) Office-based Internet Printing Flash Video Standard WMV Video High Definition WMV Video Idle
43 kbps 85 kbps 555-593 kbps 174 kbps 464 kbps 1812 kbps Based on active applications
XenDesktop with Branch Repeater
31 kbps 38 kbps 155-180 kbps 128 kbps 148 kbps 206 kbps Based on active applications
Note: These are estimates. If a user watches a WMV HD video with a bit rate of 6.5 Mbps, that...