Mode: Specifies the persistence mode used to store session state. There are four modes to choose from: Off, Inproc, StateServer, and SQLServer.
Timeout: Specifies the number of minutes of idle time before the session shuts down.
ConnectionString: Required only if Mode is set to StateServer. ConnectionString specifies the port as well as the name or address of the server where session state is stored.
SQLConnectionString: Required when Mode is set to SQLServer. It specifies the connection string needed to connect to a database server.