User guide

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8. The Web Interface server passes the connection information for the assigned XenApp server to the client
device in the form of an ICA file. The client device automatically launches the ICA file and connects
directly to the desktop of the XenApp server where the Desktop Experience Feature of Windows 2008 R2
is enabled.
9. Before opening the Desktop, the XenApp Server checks out a license from the Citrix License Server on
the client‘s behalf. The client is then connected to the desktop of the XenApp server.
3.3.7 Citrix XenApp Virtual Applications
The following steps shown in Figure 22 outline the order of operations required to access applications virtualized
using Citrix XenApp from a Citrix XenDesktop delivered desktop.
Figure 22. XenApp Application Delivery Communication Flow
1. The user accesses the XenApp Plug-in within the virtual desktop delivered by XenDesktop. The Plug-in is
used in conjunction with its corresponding Web Interface site configured on the Web Interface server.
2. The XenApp Plug-in Web Interface site queries the XML broker to determine a list of applications
available to the user. The IMA service on the XML broker queries the local in-memory application cache
in order to determine the user‘s application set. This in-memory application cache is populated from the
Local Host Cache. The XML broker constructs an XML service response and relays the application list to
the XenApp Plug-In site.
3. The user clicks on the application icon and the XenApp Plug-In site sends a request to the XML broker
requesting the address of a XenApp server that can serve that application for the user.
4. The XML broker queries the Zone Data Collector (ZDC) to retrieve the XenApp server address. The ZDC
returns this address to the XML broker. The XML broker constructs an XML service response and relays
the address to the XenApp Plug-In site.
5. The XenApp Plug-In site on Web Interface server passes the information of the chosen XenApp server to
the client device in the form of an ICA file.
6. The client device launches the ICA file connecting directly to the target XenApp server which serves the
application.
3.3.8 General Citrix XD Advantages and Value Proposition
Citrix XenDesktop is a desktop virtualization solution that delivers Windows desktops as an on-demand service to
any user, anywhere. Whether users are task workers, knowledge workers or mobile workers, XenDesktop can
quickly and securely deliver individual applications or complete desktops while providing a high-definition user
experience.