| 摘要 |
A security translator (STL) that serves for connecting a data network (N 2 ) pertaining to a lower security level to a data network (N 1 ) pertaining to a higher security level examines its own integrity at definite intervals in order to ascertain malfunctions and, where appropriate, to trigger a transition to the secure failure state. The secure failure state consists in the connection from the data network with a lower security level to the data network with a higher security level being interrupted. This is obtained by means of a watchdog circuit (WD 1 , WD 2 ) which keeps the connection (CTN) between the data network (N 2 ) with a lower security level and the data network (N 1 ) with a higher security level closed as long as it receives regular signs of life and which automatically interrupts the connection if it receives no sign of life over a predetermined period.
|
