Physical-layer security in evolving optical networks.

We are witnessing the evolution of optical networks toward highly heterogeneous, flexible networks with a widening area of application. As the bandwidth and reliability performance requirements of mission-critical applications tighten, and the amount of carried data grows, issues related to optical network security are becoming increasingly important. Optical networks are vulnerable to several types of attacks at the physical layer, typically aimed at disrupting the service or gaining unauthorized access to carried data. Such security breaches can induce financial losses to clients or loss of privacy, or cause network-wide service disruption, possibly leading to huge data and revenue losses. Awareness of system weaknesses and possible attack methods is a prerequisite for designing effective network security solutions. As optical networks evolve, new and changing vulnerabilities must be identified and dealt with efficiently. To this end, this article provides a comprehensive overview of potential physical-layer attack scenarios in current and future optical networks. It then proposes a general security framework, outlining possible strategies for dealing with such attacks, meant to aid in the development of efficient provisioning, monitoring, protection, and restoration schemes in the context of optical-layer security.