Product Documentation

Configuring XenApp Acceleration

May 23, 2013

XenApp acceleration applies to both the ICA and CGP protocols within XenApp. The CloudBridge appliances, XenApp servers, and XenApp clients provide cooperative acceleration of XenApp connections, providing substantial speedup compared to XenApp alone. This cooperation requires up-to-date versions of all three components.

XenApp compression dynamically switches between memory based compression for interactive channels (such as mouse, keyboard, and screen data) and disk based compression for bulk tasks (such as file transfers and print jobs). Compression ratios increase as compression history fills, increasing the amount of data that can be matched against new data. XenApp compression provides several times as much data reduction as does unassisted XenApp, often exceeding 50:1 on repetitive bulk transfers such as printing or saving successive versions of the same document.

XenApp compression achieves high link utilization without congestion, by preventing users from interfering with each other.

To enable XenApp acceleration

  1. If the appliance that has been upgraded to CloudBridge 6.x from an earlier release, check the ICA service class policy. On the Configuration: Service Classes page, the ICA service class should show disk in the Acceleration column and ICA Priorities in the Traffic Shaping column. If not, edit the service class definition.
  2. Update XenApp 4.x servers and clients. (Not necessary on XenApp 5.0 or later). Use Presentation Server 4.5 with Hotfix Rollup Pack PSE450W2K3R03 (Beta) or later. This release includes the following server and client software, both of which must be installed for XenApp compression:
    1. Server package PSE450R03W2K3WS.msp or later.
    2. Client version or later.
  3. Update XenDesktop servers and clients to release 4.0 or later.
  4. Verify XenApp server registry settings. (Not necessary on XenApp 5.0 or later.) On the XenApp servers, verify the following settings and correct or create them as necessary:
    HKLM\System\CurrentControlSet\Control\Citrix\WanScaler\EnableForSecureIca = 1 
    HKLM\System\CurrentControlSet\Control\Citrix\WanScaler\EnableWanScalerOptimization = 1 
    HKLM\System\CurrentControlSet\Control\Citrix\WanScaler\UchBehavior = 2

    These are all DWORD values.

  5. Open and use XenApp connections, between updated XenApp clients and servers, that pass through the updated CloudBridge. By default, these sessions use CGP. For ICA, on the client, under Citrix Program Neighborhood, clear the Custom ICA Connections check box. Then, right-click a connection icon, navigate to Properties > Options, and clear the Enable Session Reliability check box.
  6. Verify acceleration.

    After you start XenApp sessions over the accelerated link, accelerated ICA connections should appear on the appliance’s Monitoring: Connections page. A compression ratio of greater than 1:1 indicates that compression is taking place.