Abstract-A local lightwave network can be constructed by employing two-way fibers to connect nodes in a passive-star physical topology, and the available optical bandwidth may be accessed by the nodal transmitters and receivers at electronic rates using wavelength-division multiplexing (WDM). The number of WDM channels, w, in such a network is technology-limited and is less than the number of network nodes, N, especially if the network should support a scalable number of nodes. We describe a general and practical channel sharing method, which requires each node to be equipped with only one transmitter-receiver pair, and in which each WDM channel is shared in a time-division multiplexed fashion.We also develop a general model for analyzing such a sharedchannel, multi-hop, WDM network. Our analysis yields a counterintuitive result: it is sometimes better to employ fewer channels than a larger number of channels. We explore bounds on the ranges of w which admit queueing stability-using too few or too many channels can lead to instability. We also obtain an estimate for the optimal number of channels that minimizes network-wide queueing delay.

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Protected Core Networking (PCN) is an approach to creating a secure and flexible network and communications infrastructure that supports network enabled capability (NEC) operations. The real-time automated risk assessment (R-TARA) provides a theoretically and practically sound method for risk assessment in the Protected Core. The purpose of the R-TARA is multifold. On the one hand it provides a global metric, which could be used by the network operator to assess the overall security level of the network and its evolution over time. On the other hand, the results of R-TARA can be used in order to achieve dynamic accreditation. Finally, R-TARA local risk metrics, e.g. susceptibility to DoS attacks, can be used for dynamic routing decisions. We propose use of Bayesian networks, known from operational risk assessment, for PCN risk assessment and we provide analytical and simulative evaluation of R-TARA mechanisms.

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