0ed2c426_3____The_ClusterManager_object__Attribute
[Description] The initial maximum time interval, in seconds, between client requests before a session is invalidated. A negative value will result in sessions never timing out. If the attribute is not provided, a default of 1800 seconds (30 minutes) is used. This attribute provides the initial value whenever a new session is created, but the interval may be dynamically varied by a servlet via the setMaxInactiveInterval method of the HttpSession object. [Attribute] 
maxInactiveInterval
Apache Tomcat 7 Configuration Reference (7.0.63) - The ClusterManager object