A new approach to provide the differentiated levels of network survivability under a double node failure

In this paper we propose a class-based protection algorithm providing fast service recovery in WDM networks in case of a simultaneous failure of two network elements. We focus on providing various levels of service survivability in order to correspond to differentiated requirements of end-users. We show that assuring the service survivability in case of a double failure requires up to 40% more total link capacity, compared to the results for protection against a single node failure. The time of service recovery is also increased. However, the values of service recovery time may be reduced by limiting the scope of backup path protection.