This read-write Integer32, in seconds and ranging -1 to 65535, sets how long the MG waits before transitioning from gracefulOutOfService to forcefulOutOfService, with -1 meaning the MG drains automatically once the last resource is released. An admin tunes this to give the MGC enough time to clean up connections during a planned shutdown, balancing graceful service drainage against how long a maintenance window can be held open. Setting this to -1 would suit a gateway an admin wants to let finish all active calls naturally rather than force a hard cutover after a fixed timer.