LAST MODIFIED DATE: November 21, 2007

VERSION: This applies to Connectivity Secure Shell version 10.0

PROBLEM:

Is there any way to provide a faster response when running /usr/dt/bin/Xsession through a Secure Shell connection via Exceed 10

SOLUTION:

To improve performance time, you can Disable the Nagle algorithm within the secure shell tunnel.

Here are the steps when launching Xsession from Xstart with Secure Shell start method.

1. Launch Xstart
2. Set the startup method to SECURE SHELL
3. Click the SETTINGS button
4. Go to the SECURITY tab, click on PROPERTIES
5. Click the CREATE button on the SECURE SHELL CONFIGURATION dialog box
6. Enter the tunnel name and the hostname field information on the ADD NEW TUNNEL dialog box and click OK
7. Now on the SECURE SHELL CONFIGURATION dialog box, you will see your new tunnel just created
8. Click the EDIT button
9. On the TUNNEL PROFILE dialog box, go to the CONNECTION, ADVANCED portion of the tree and deselect the ENABLE NAGLE ALGORITHM
10. Click OK on the TUNNEL PROFILE dialog box
11. Click OK on the SECURE SHELL CONFIGURATION dialog box
12. Click OK on the XSTART SETTINGS dialog box
13. Enter the appropriate login credentials and command line to run Xsession for your host

There should now be some performance gain in running Xsession via a Secure Shell connection (with disabling the NAGLE ALGORITHM).

Normally, the Nagle algorithm optimizes network traffic by addressing the small packet problem. The Nagle algorithm buffers small packet requests until an acknowledgment is sent for the packets.

However, in an interactive environment like Xsession (CDE), the Nagle algorithm slows down response time.

If the response time is still not increased, please make an additional change to your secure shell tunnel profile, as follows:

Edit the Secure Shell Tunnel > Properties > Connection > General > Advanced:

Default Window Size 64000
Maximum Packet Size 32KB (this should be the default value)

With the above two changes you will notice a significant increase in your x-windows emulation over secure shell.