Design and evaluation of multi-layer survivability for SDH-based ATM networks

To realise end-to-end survivable networks several single-layer recovery mechanisms at different layers have to interwork. This paper proposes a classification of multi-layer survivability strategies, and presents a performance evaluation of a sequential bottom-up interworking approach for an SDH-based ATM test network. The SDH layer employs dynamic distributed flooding-based recovery, whereas the ATM layer utilises backup VP restoration. It is shown that multi-layer survivability provides a considerable availability gain even within the crucial 2 seconds time period. Moreover, it turns out that an SDH recovery ratio based technique to pass the responsibility between layers is to be preferred to a hold-off time based technique.