Patent ID: 7689689

Claim:
A method for protecting a networked industrial controller from network storms, the networked industrial controller has a real-time operating system and communication components performing communication exchanges with connected networks, the method comprising steps of: (a) Initializing a watchdog thread monitor thread within the real-time operating system's kernel to have the watchdog thread monitor thread a kernel level priority; (b) configuring a watchdog thread to periodically (every T Alive time) send an alive event signal to the watchdog thread monitor thread if all other threads of application programs are operating normally; (c) starting the watchdog thread monitor thread waiting for receiving the alive event signal within a timeout period T AliveTout (T AliveTout is longer than T Alive ); (d) identifying a network storm in response to the alive event signal; and (e) controlling the communication exchanges in response to the alive event signal and current phase of the watchdog thread monitor thread; wherein the watchdog thread monitor thread has four different phases: (i) Normal; indicating that the networked industrial controller is communicating with the connected networks normally; (ii) Disabling Communication Exchanges; indicating that the networked industrial controller is in the process of disabling communication exchanges with the connected network; (iii) Communication Exchanges Disabled; indicating that the communication exchanges from the networked industrial controller have been disabled and no data is exchanged with the connected networks; (iv) Re-enabling Communication Exchanges; indicating that the networked industrial controller is in the process of enabling communication exchanges with the connected networks.