Cisco processors have timers that guard against certain types of system hangs. The CPU periodically resets a watchdog timer. The watchdog timer basically controls the time of each process. If the timer is not reset, a trap occurs. If a process is longer than it should be, the watchdog timer is used to escape from this process.
There are two main types of watchdog timeouts. The first type is usually caused by a software problem and is reported in one or both of these ways: