  The DDoS attack landscape is growing at an unprecedented pace. Inspired by
the recent advances in optical networking, we make a case for optical
layer-aware DDoS defense (O-LAD) in this paper. Our approach leverages the
optical layer to isolate attack traffic rapidly via dynamic reconfiguration of
(backup) wavelengths using ROADMs---bridging the gap between (a) evolution of
the DDoS attack landscape and (b) innovations in the optical layer (e.g.,
reconfigurable optics). We show that the physical separation of traffic
profiles allows finer-grained handling of suspicious flows and offers better
performance for benign traffic in the face of an attack. We present preliminary
results modeling throughput and latency for legitimate flows while scaling the
strength of attacks. We also identify a number of open problems for the
security, optical, and systems communities: modeling diverse DDoS attacks
(e.g., fixed vs. variable rate, detectable vs. undetectable), building a
full-fledged defense system with optical advancements (e.g., OpenConfig), and
optical layer-aware defenses for a broader class of attacks (e.g., network
reconnaissance).
