Hi Manikantan,
There is a parameter "System.UI.SessionExpirationWarningInterval" defined in Parameters.table file to configure timeouts. If a user’s session becomes inactive, Ariba Buyer issues a warning, and then closes the session (times it out) if the user does not respond to the warning. The value is an integer, representing a number of milliseconds. The default value is 60000, or one minute. If the user does not respond to the warning in the specified length of time, Ariba Buyer times out the session.
Thanks,
Amit