In this report we have illustrated the criteria of early warning alert and procedures to activate the back-up network for a high-survival radio network operating in the HF band.
The early warning process has been analysed by a general overview of the possible scenarios of the backbone HF radio network assuming two different potential terroristic attacks.
Some intrinsic requirements and characteristics of the SWING system have been accounted for: simplicity, resilience and scalability. The main Internet supervision methods available in the technical literature and able to detect the occurrence of a network fault have been illustrated.
Finally a typical scenario in which the broadband Internet becomes available again has been discussed presenting the procedure by which the SWING HF links are deactivated and the broadband Internet links are reactivated.
The complete process required for the activation of the HF back-up network after a warning alert event has been analysed assuming a realistic network configuration and two different potential terroristic attacks. In this case the time needed to guarantee a safe basic internet connection via SWING to the node under attack has been simulated in less than 10 minutes from the triggering event. However notice that the effective time required for a complete SWING activation/ deactivation will depend on the event sequence of the terroristic attack and on the complexity of the effective physical topology of the SWING network.