Setup and Configuration of Intel AMT > Configuration Settings > KVM Configuration > Use Cases > Enabling and Disabling Back-to-Back Framebuffer Update
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Enabling and Disabling Back-to-Back Framebuffer Update

Enabling back-to-back framebuffer update allows you to speed up transmission of network traffic on networks that have low bandwidths. Enabling the feature means that the transmitter will not wait for acknowledgement that the framebuffer has been received before transmitting the next framebuffer.

Note that enabling this feature can cause a heavier load on the network, as the traffic is transmitted without waiting for acknowledgement.

Note: The back-to-back setting has effect only during the current KVM session. It should be set only during a session (and not before). When the KVM session ends, the back-to-back mode changes back to its default value (disabled).

Note for Viewer developers:

If the user changes the pixel format when back-to-back is enabled, it may cause a crash of the Viewer software. To prevent a crash, the Viewer software should do one of the following:

     Prevent the user from accessing the menu that changes pixel format.

     Follow the procedure below to prevent the Viewer from crashing when pixel format is changed when back-to-back mode is enabled:

     For RFB4 protocol: The Viewer should disable back-to-back mode , send an RFB4 Sync message to the firmware, wait for an RFB4 Sync response from the firmware, send the SetPixelFormat RFB message with the new format, and then re-enable back-to-back mode.

     For RFB3 protocol - The Viewer should disable back-to-back mode, wait until the last back-to-back framebuffer is received, send the SetPixelFormat RFB message with the new format, and then re-enable back-to-back mode.

The following steps show how to enable or disable the feature:

1.  Ensure that the KVM interface is enabled: See Enable/Disable the KVM Interface.  If it is enabled, continue to the next step.

2.  Set the BackToBackFbMode property of the IPS_KVMRedirectionSettingData class to true (to enable) or false (to disable).

Click here for a snippet demonstrating this step

You can execute this snippet by inserting it into the execution template found here.

  

$kvmRedirectionSettingDataRef=$wsmanConnectionObject.NewReference("SELECT * FROM IPS_KVMRedirectionSettingData WHERE InstanceID='Intel(r) KVM Redirection Settings'")

$kvmRedirectionSettingDataInstance=$kvmRedirectionSettingDataRef.Get()

$kvmRedirectionSettingDataInstance.SetProperty("BackToBackFbMode","true")

$kvmRedirectionSettingDataRef.Put($kvmRedirectionSettingDataInstance)

 

 

 

 

See Also:

   KVM Application Developer’s Guide

 

 

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