03-2 Application Delivery

Application Delivery - When delivering an application with XenApp, it is important for you to know the different application delivery methods available and to determine which method best fits the needs of the environment. Depending on the type of application, the end users accessing the application, and the delivery method, applications are:
- Installed on a XenApp server
- Streamed from a file or web server to a XenApp server
- Streamed from a file or web server to the end user device
- Accessed as a XenApp server-hosted desktop

Applications Installed on a XenApp Server - An application installed on a XenApp server is processed on the server and only virtual channel information is sent to the end user device. A Citrix Plug-in, such as the Citrix Receiver, is required to access applications installed on XenApp servers.

Benefits	Considerations
Applications are installed centrally on XenApp servers, which can ease application maintenance. Host server operating system resources are used, which allows for scaling of application performance regardless of the end user device in use. Only virtual channel information is sent to the end user device, which minimizes bandwidth and increases security. Applications requiring significant bandwidth for the end user device and the server are good candidates for direct installation on a XenApp server	Application resources need to be installed at the server level because the applications are processed on the XenApp servers. XenApp server resources must be increased in order to scale the number of concurrent applications in use. Applications that will not run on a server OS or on a multi-user kernel should not be installed directly on a XenApp server. Applications that are 32-bit should not be installed directly on a server running XenApp 6.x or later

Benefits

Considerations

Applications are installed centrally on XenApp servers, which can ease application maintenance.
Host server operating system resources are used, which allows for scaling of application performance regardless of the end user device in use.
Only virtual channel information is sent to the end user device, which minimizes bandwidth and increases security.
Applications requiring significant bandwidth for the end user device and the server are good candidates for direct installation on a XenApp server

Application resources need to be installed at the server level because the applications are processed on the XenApp servers.
XenApp server resources must be increased in order to scale the number of concurrent applications in use.
Applications that will not run on a server OS or on a multi-user kernel should not be installed directly on a XenApp server.
Applications that are 32-bit should not be installed directly on a server running XenApp 6.x or later

Applications Streamed to a XenApp Server - An application that is streamed to a XenApp server allows end users to access it as if it were installed directly on the XenApp server. A Citrix Plug-in, such as the Citrix Receiver, is required to access applications streamed to XenApp servers.

Benefits	Considerations
This method allows for a centralized update process across multiple XenApp servers. This method allows for multiple versions of an application to be delivered without using separate XenApp servers. For example, Microsoft Word 2007 and 2010 can be delivered from the same XenApp server.	It is recommended to pre-cache commonly accessed streamed applications on XenApp servers to enhance performance and reduce the application launch time on the end user device.

Environments with an existing Microsoft App-V infrastructure can stream App-V packages to XenApp servers and end user devices by using the Citrix App-V Integration Kit.For more information about the App-V Integration Kit, see Citrix article CTX126423

Applications Streamed to an End User Device - An application that is streamed to the end user device is streamed from a file or web server and launches on the end user device as a local application. The application uses the end user device resources as opposed to using XenApp server resources. A Citrix Plug-in, such as the Citrix Receiver, is required to access applications streamed to end user devices. The Citrix offline plug-in is used for applications configured for offline access.

Benefits	Considerations
End user device resources are used for an application that requires large amounts of processing power. Applications do not need to be installed on the virtual or physical desktop. Application compatibility with the desktop operating system can be better than application compatibility in a server-based computing model. It is possible to stream and run multiple versions of the same application at the same time on a virtual or physical desktop. Applications that require advanced video capabilities are good candidates for offline applications.	End user devices that need access to offline applications must have the Citrix offline plug-in installed. Clients that do not support application streaming, such as non-Windows clients, cannot launch offline applications. Applications are processed within an isolated environment when launched on a end user device.

Benefits

Considerations

End user device resources are used for an application that requires large amounts of processing power.
Applications do not need to be installed on the virtual or physical desktop.
Application compatibility with the desktop operating system can be better than application compatibility in a server-based computing model.
It is possible to stream and run multiple versions of the same application at the same time on a virtual or physical desktop.
Applications that require advanced video capabilities are good candidates for offline applications.

End user devices that need access to offline applications must have the Citrix offline plug-in installed.
Clients that do not support application streaming, such as non-Windows clients, cannot launch offline applications.
Applications are processed within an isolated environment when launched on a end user device.

Benefits	Considerations
Provides end users with a familiar interface. Allows thin clients to replace full PCs or desktops. Allows remote or home end users to access a full corporate workspace.	Provides end users with access to the resources on a server which can result in configurations and settings being changed and cause server vulnerabilities. Consumes more resources on a XenApp server because an entire desktop is provided for each connected end user and desktop interactions are transferred to the XenApp server.