Packet switched data network (PSDN) having local area network (LAN) interface and overload control method thereof

摘要

In a Packet Switched Data Network (PSDN) having a Local Area Network (LAN) interface, an auxiliary controller controls all protocols of the LAN interface through an interrupt routine and transmits a state-monitoring signal after processing the protocols. A main controller compares a transmitting period of the state-monitoring signal transmitted from the auxiliary controller with a critical time and changes a state of the auxiliary controller from a usable state to an unusable state or from the unusable state to the usable state in accordance with a result of the comparison. As a result, even when traffic is congested in a certain LAN interface or a certain LAN interface is infected with a virus to such an extent that the interface fails to operate, an overload in a main processor is prevented.