Robert Wilkinson - IT Consultancy for Citrix | Microsoft | VMWare | End User Computing

XenApp or RDS

Why XenApp and not Microsoft Windows Remote Desktop Services?

Remote Desktop Services is the very foundation of session based computing technology that Citrix XenApp builds upon. Without RDS, XenApp would not work. So the quickest answer to the question is: XenApp is more of a feature rich enterprise grade extension to RDS which is essential in so many ways for large organisations to be agile, secure, efficient and ahead of the technology curve.

Citrix XenApp Platinum Features not available with Microsoft RDS:

  • Speed and security (ICA/HDX Protocol) – The Citrix ICA Protocol has proven track record in out performing the RDP protocol in speed and security.
  • Pre-launch– With the pre-launch feature, a “blank” session can be created when the user logs  on or to a certain point in time (when the user is already logged in).
    This pre-launch session shortens the start time of the first application.
  • Citrix HDX – outperforms Microsot RemoteFX adaptive graphics by a mile.
  • Save on storage costs – Citrix Provisioning Server (XenApp Platinum) – Provisioning Services allow you to stream standardized images of Citrix XenApp servers to virtual or physical servers. Using a SAN can save a considerable amount of disk space when one image can serve multiple instances. e.g. Conventional clones would mean C: drive @ 70GB x 100 Servers = 7TB versus only one C drive at 70GB for all 100 servers. Why apply security updates and patches to 100 servers individually when you only have to patch one gold disk image?
  • Better monitoring – Director (Edgesight) – Advanced Monitoring (XenApp Platinum).
  • More secure and integrated remote access – Netscaler gateway (Additional purchase)
  • Citrix Single Sign on – An agent which is running on the Citrix XenApp servers in user mode, transmits user names and passwords into login screens.

Citrix HDX

Citrix HDX is designed for WAN connections and has many different configuration options although typical use cases are as follows:
  •  Client-side rendering – The screen contents will be disassembled and assembled on the client side. Flash content can be transferred directly to the client and rendered there.
  • Server-side rendering
  • HDX Realtime engine – Is unified communications application aware – HDX Realtime engine embedded agent in Reciever is able to redirect Skype(Lync) audio video to the mobile device or local computer where internet is local creating shortest hop aware instance of audio/video
HDX Features
  • Windows Server 2012 and Windows 8 support — Deliver a high-definition user experience on Windows 8 virtual desktops and physical machines. HDX 3D Pro has also been upgraded to support Windows 8.
  • Desktop Composition Redirection — Extend the Aero Redirection feature introduced in XenDesktop 5.5 to provide users with a more fluid Windows 7 Aero or Windows 8 desktop experience by leveraging the graphics processing unit (GPU) or integrated graphics processor (IGP) on supported Windows user devices for local DirectX graphics rendering. This feature delivers rich multimedia applications to user devices, while maintaining high scalability on the server.
  • Windows Media client-side content fetching — Enable a user device to stream multimedia files directly from the source provider on the Internet or intranet to improve network utilization and server scalability.
  • Multicast support — Reduce bandwidth consumption when streaming live video to branch offices. Multicast support enables a single Windows Media source transmission to support multiple users.
  • Real-time multimedia transcoding — Enable audio and video streaming to mobile devices, improving the way that Windows Media content is delivered. Host-based transcoding provides a seamless user experience, even in extreme network conditions. To improve server scalability, if the Virtual Delivery Agent (VDA) has a supported graphics processing unit (GPU) for hardware acceleration, transcoding is done in the GPU.
  • User Datagram Protocol (UDP) audio for Server OS machines — Extend support for audio delivery over UDP/RTP to Server OS machines. This feature delivers superior audio quality for real-time applications like video conferencing and streaming media, even in environments when there is packet loss or congestion.
  • Webcam video compression — Reduce bandwidth consumption to improve performance when using supported video conferencing applications.
  • HDX 3D Pro — Deliver applications with graphics processing units (GPUs) for hardware acceleration to the desktop. This includes 3D professional graphics applications based on OpenGL and DirectX.
  • Server-rendered Rich Graphics and Video — Deliver rich graphics (including Windows 8 or Windows Aero) to virtual desktop users on any client, platform, and bandwidth condition by rendering the content on the server. When users have the latest Citrix Receiver, they will also notice improved performance for server-rendered video.
  • Improved Flash Redirection — Determine when to redirect Adobe Flash content to the user device for local rendering based on the user’s network type and environment. Flash Redirection helps reduce server and network load, resulting in greater scalability while ensuring a high-definition user experience.

Microsoft RemoteFX

RemoteFX divides the screen content into text, graphics and video and transcodes the content, for example videos in H.264. On the client the content is composed again.
Disadvantages of RemoteFX:
With the use of hypervisors, virtualization of the GPU can not be provided currently. Even remote apps can not use RemoteFX.