NOTE:
Session Reliabilty:
Session Reliability keeps sessions active when network connectivity is interrupted. Users continue to see the application they are using until network connectivity resumes.
ICA Keep Alives:
Enabling this setting prevents broken connections from being disconnected. If XenApp detects no activity, this setting prevents Remote Desktop Services from disconnecting the session. XenApp sends keep-alive
Messages every few seconds to detect if the session is active. If the session is no longer active, XenApp marks the session as disconnected.
*IMPORTANT:* ICA Keep-Alive does not work if you are using Session Reliability. Configure ICA Keep-Alive only for connections that are not using Session Reliability.