Disaster survivability in optical communication networks

With the frequent occurrences of natural disasters damaging large portions of communication networks and the rising risk of intentional attacks, network vulnerability to multiple cascading, correlated, and collocated failures has become a major concern. Optical backbone networks provide highly-scalable connectivity across large distances. These networks exploit optical technology to carry huge aggregated data and can support "higher-layer" networks, such as SONET, Ethernet, IP, MPLS, ATM, etc. Given the high complexity and scale of backbone networks, multiple correlated failures can have a devastating impact on topological connectivity, which in turn can cause widespread "end-to-end" connection-level disruptions. These outages may affect many applications/services supported by the optical layer, irrespective of the importance of the service and/or sensitivity of the carried data. Hence, it is crucial to understand the vulnerability of optical backbone networks to disasters and design appropriate countermeasures. In this paper, we present a general classification of the existing research works on disaster survivability in optical networks and a survey on relevant works based on that classification. We also classify disasters based on their characteristics and impact on communication networks and discuss different ways to combat them. We conclude the paper with open issues and challenges. (C) 2013 Elsevier B.V. All rights reserved.