Eavesdropping-Aware Routing and Spectrum Allocation in EONs Using Spread Spectrum Techniques

In this work, eavesdropping-aware routing and spectrum allocation (RSA) techniques are proposed for elastic optical networks (EONs) using orthogonal frequency division multiplexing (OFDM). To introduce physical (optical) layer security and protect these networks against eavesdropping attacks, spread spectrum (SS) with signal overlapping techniques are used to encode each requested confidential connection. In order to attain access to the signal and compromise a confidential connection, an eavesdropper will now have to lock on the correct frequency, determine the correct code and symbol sequence amongst co-propagated overlapped signals, and decode the signal. Different routing strategies and a novel spectrum allocation technique are proposed in an attempt to add an extra layer of security for confidential connections, while also considering spectrum utilization. Performance results demonstrate that while each confidential connection now requires more spectrum as a result of spreading in the bandwidth domain, the overall network spectrum usage is not increased proportionally to the spreading factor due to the utilization of spectrum overlapping techniques.