An Optical Transport Network (OTN) (comprising a number of OTN nodes) uses an Internet Protocol (IP) based control plane (out-of-band signaling on a separate wavelength). Each OTN node of the IP-based control plane performs dual-feeding and dual-selecting of signaling messages on diverse signaling paths....http://www.google.se/patents/US7099327?utm_source=gb-gplus-sharePatent US7099327 - Data communications networks with high performance and reliability
