Surviving multiple network failures using shared backup path protection

This paper studies the possibilities of protecting backbone networks from multiple simultaneous failures. Although methods that prepare the networks to survive single failures were extensively studied in the literature, in order to provide extra high availability for mission-critical applications, the possibility of more than one simultaneous failure has to be considered too. The general technique of protecting a traffic flow is to establish a backup path where the traffic is redirected when a failure occurs along its active path. Using this technique the total capacity reservation is at least doubled compared to the non-protected case. To avoid this large amount of bandwidth reservation by the backup paths, the shared backup path protection paradigm can be used, which is a promising scheme favored by the Internet engineering task force. In this paper the two backup path based protection scheme is introduced, which provides survivability against any two simultaneous failures. Further, a novel shared protection strategy is proposed that improves the failure tolerance of the traditional single backup path based protection. The performance of the different protection types is examined through simulations.