D-Link DIR-615 User Manual page 78

Section 3 - Configuration
Time Out: The number of seconds of idle time until the router considers the session terminated. The initial value of Time Out depends on the type and state of the
connection.
. 300.seconds - UDP connections.
. 240.seconds - Reset or closed TCP connections. The connection does not close instantly so that lingering packets can pass or the connection can be
re-established.
. 7800.seconds - Established or closing TCP connections.
D-Link DIR-615 User Manual 74