Improve Performance over a Slow Network

You can use the Reflection X Advantage Remote Session Services when your network configuration causes delays that make running a remote X client application difficult. To support this feature from the standalone X Manager, you can install the Remote Session Services feature on your X client host, as described below.

Note: The steps below use the standalone X Manager. You can also configure X Manager for Domains to address problems with high latency or bandwidth. Once you've set up a Reflection X Advantage domain, this support is available without the extra step of installing Reflection X Advantage on the X client host. For domain setup information, search on "Domain Setup: Improve Performance Over a Slow Network" in the Reflection X Advantage Help.

With remote session services enabled, when you start a session, Reflection X Advantage creates two X servers. An X server display runs on your Windows workstation (shown on the left below) and a second "headless X server" runs on the X client host (shown on the right). In high latency networks, this configuration improves performance by short circuiting some of the data exchange over the network. With the headless X server running on the client host (or on a nearby host), client/server exchanges that don't change the display pass between the client and the headless X server, but aren't sent over the network to the X server display on the workstation. This eliminates round trip network messages and dramatically improves the response time you see on your workstation. In addition, if the network exhibits low bandwidth, the protocol is compressed between the remote session and the X server display.

Data flow for a distributed X Manager session

The first procedure installs the Remote Session Services feature on your X client host to support this kind of connection.

Before you begin

  • Use any of the procedures described under Starting an X Client to test an X client connection to your UNIX host. In the procedures that follow you'll modify the client definition to use the Remote Session Services feature.

Configure your X client host to support remote session services

  1. Return to the Download library page, download the package for the UNIX system on which you run your X clients, and copy this file to the X client host.
  2. Unzip the download file. For example:

    unzip rx-advantage-5.0.nnn-eval-linux.zip

    The expanded download file contains binary files (*.bin) for installing on different platforms. Locate the appropriate file for your UNIX platform. (You don't need the file that begins with rxa_help. This installs optional local help files that aren't used in this configuration.)

  3. Log on as root and navigate to the directory that contains the installation file.
  4. Change the permissions of the installation package to give execute permissions. For example:

    chmod 744 rxa-5.0.0.nnn-eval-i586-linux.bin

  5. Start the installation program. For example:

    ./rxa-5.0.0.nnn-eval-i586-linux.bin

    Note: The command above launches the InstallAnywhere installation program which requires an X11 Windows display. If a graphical display is not available the installation will run in console mode.

     

  6. When you reach the Choose Install Type screen, select Remote Session Services.

    install_remote_services.png

  7. Complete the installation using defaults.

 

The next procedure creates a new session definition that you can use to test the Remote Session Services feature.

Create a new session definition that uses remote session services

  1. Return to the Windows computer on which you created and tested an X client definition and start X Manager.
  2. Under Session Definitions, click plus sign to create a new session. For Session Name, enter "RSS Session."
  3. Select the display option appropriate for your X client:
    • If you want your client application to run on your desktop, select Show clients on my desktop.
    • If your client command launches a desktop environment such as KDE, CDE or GNOME, select Show clients on X terminal desktop.
  4. (Optional) If you want the session to stop when you exit your client, change On last client to Stop session.
  5. Under Remote session services:
    • Select High-latency network performance.
    • For Host name, specify the name of the X client host on which you installed the Remote Session Services feature.
    • For User name and Password, specify your credentials on the X client host.

 

The next procedure configures your client to connect using this new session.

Start a client using your new session and view the session statistics

  1. In X Manager, under X Clients, select your X client definition.
  2. For Default session, use the drop-down list to select the "RSS Session" you just configured.
  3. Double-click the X client definition and log onto your host. You should see your X client display.
  4. In X Manager, under Session Definitions, select your running session, which is identified with this icon: session running joined
  5. In the Session Status pane, view the X Servers section. Depending on the latency in your network, you will see either one or two X servers listed:
    • If latency is not a problem, you see a single X display server (running on your X Manager workstation). In this case, all protocol is forwarded directly to this X server display.
    • If latency is a problem (greater than 10 ms), you'll see two servers – the display server running on the X Manager workstation and a second "headless server" running on the UNIX host. This configuration improves performance by short circuiting many protocol queries. This reduces the number of round trips and the amount of data that needs to pass over the network to the X server display on your workstation.