A link state advertisement (LSA) protocol for optical transparency islands

Plug and play optical (PPO) nodes can be used to ease the deployment of optical networks. Once plugged, PPO nodes provide all-optical circuits between client nodes to alleviate the electronic processing bottleneck of high speed networks. PPO nodes must self-adjust to changes of the optical physical topology and fiber propagation characteristics, and provide wavelength routing functionalities to client nodes. This paper presents a protocol, the TI-LSA protocol, for physical topology discovery at the PPO node layer, e.g., it may be used to advertise available optical resources and changing conditions of the optical physical layer. The protocol is based on the link state advertisement (LSA) principle and modified to take advantage of the transparency island (TI) properties in the optical data plane. As discussed in the paper, the proposed TI-LSA protocol is a scalable solution to the problem of topology discovery and update in PPO networks when the optical transparency island size is relatively small.