A Link State Advertisement Protocol for Optical Transparency Islands

Plug and play optical (PPO) nodes enable fast, re-configurable, and flexible ad hoc deployment of optical networks. Once plugged, the PPO nodes provide all-optical circuits between client nodes to alleviate the electronic processing bottleneck of high speed networks. To offer these wavelength routing functionalities to client nodes the PPO nodes must self-adjust to possible changes of the optical physical topology and fiber propagation characteristics. To discover such changes the PPO nodes must make use of a link state advertisement (LSA) protocol that is scalable in the number of plugged PPO nodes. This paper describes a scalable LSA protocol with constrained message flooding to match the limited propagation reach of the optical signal, i.e., the PPO node transparency island (TI). Scalability is thus achieved naturally by limiting the link state advertisement scope to only those PPO nodes that need to receive the link updates. As discussed in the paper, the proposed protocol appears to be a viable solution when the TI size is relatively small, e.g., in optical networks without signal regeneration.