Citrix Application Streaming, introduced in XenApp 4.5, provides a means to simplify application deployment to end users. Applications can be installed and configured on a single machine, called the profiler, and delivered/streamed to any XenApp server or client desktop on demand.

Features of Application Streaming include:

•Install applications once on the Profiler and distribute to file server repositories across the enterprise

•Seamless updates in that applications can be updated once on the Profiler and then delivered to the end users

•Applications run within isolation environments that keep applications from conflicting with each other

•Application Caching – application files can be cached to the local client allowing faster access. Cached files are updated should newer versions exist.

•Applications can be easily deployed to farm servers as you can choose to stream applications from the file server repository without the need to install the applications on the servers themselves

•Dual Mode Streaming – XenApp servers can be configured to stream application profiles directly to client machines, or streamed from the XenApp server.

•Offline Access – once delivered, streaming applications are available to the users even if they are disconnected from the network

A typical Application Streaming infrastructure is shown below:

The components involved in a Citrix Application Streaming infrastructure are:

1. Citrix License Server
XenApp Server 4.5 Enterprise and Platinum editions include Application Streaming to both the desktop and to XenApp Server. After installing Hotfix Rollup Pack 1 for XenApp Server 4.5, Application Streaming no longer requires a separate license but consumes one Platinum or Enterprise license.

Only one license is consumed per user per device. A user can stream to the desktop, stream to the server, and run ICA sessions simultaneously and consume only one license. The license files must be on version 4.5 (or later) Citrix license server.

2. XenApp Server Farm
Streaming applications are published using the Access Management Console and accessed by users via the Program Neighborhood Agent or the Web Interface server.

3. Streaming Profiler
The machine used to create the streaming application “profiles”. The Profiler should provide a run-time environment that is close to your end user environment.
For example, if you will be streaming applications to a XenApp 4.5, Windows 2003 Server, the Profiler should be Windows 2003 Server. It may be necessary to have multiple Profilers, especially if streaming applications directly to client workstations.

4. Streaming Client
Once the user logs into the XenApp environment through the Program Neighborhood Agent or the Web Interface and their applications have been enumerated, the streaming client, which runs as a service on client workstations, sets up an isolation environment and streams application files to the workstation on demand.

A high level overview of creating an application profile is as follows:

1.Install the Profiler system using the XenApp Server Components CD. Choose Presentation Server Utilities, then Install Citrix Streaming Profiler for Windows.

2.Install and customize an application (or application suite) on the Profiler.

3.Select the applications to list within and build the profile.

4.Save the profile to a server file share.

Publishing Streamed Applications
Streamed application packages are published through the Citrix Access Management Console and can be made available to users in three ways:

1. Streamed to Client
Enables users to stream a profiled application from the file share repository to their workstation and launch it locally. This requires the Citrix Streaming Client be installed on the workstation.

2. Accessed from Server
A profiled application is streamed from the file share repository to the XenApp server, then launched by the user within an ICA session. The Citrix Streaming Client is installed on each XenApp server.

3. Streamed if possible, otherwise access from a server (Dual Mode)
Combines the two options above. This option enables users to stream directly to their workstation if the Citrix Streaming Client is installed and if it is not, the client will access the application from the XenApp server.

There are many additional Application Streaming features and options we could discuss but since this is to be an introduction, I’m forcing myself to stop here. Perhaps we’ll talk about Offline Access, updating profiles, or isolation environment rules in a future post.