Risk assessment of end-to-end disconnection in IP networks due to network failures

Abstract

Restoration and protection switching mechanisms in IP networks are triggered by link or node failures to redirect traffic over backup paths. These mechanisms are no longer effective if a network becomes disconnected after a failure. The risk of end-to-end disconnection increases if the nodes of a network are only sparsely meshed or if multiple network failures occur simultaneously. This leads inevitably to violations of service level agreements with customers and peering network providers. In this paper, we present a method to assess the risk of end-to-end disconnection in IP networks due to network failures. We calculate the disconnection probabilities for all pairs of network nodes taking into account a set of probable network failures. The results are considered from different perspectives. This helps to identify weak spots of the network and to appropriately upgrade its topological infrastructure with additional links. We implemented the concept in a software tool which assists network providers with assessing the risk of disconnection in their network prior to any network failure and to take appropriate actions. © Springer-Verlag Berlin Heidelberg 2006.