A telecommunications network having a ring topology overlaid with an Ethernet. An add/drop multiplexer (ADM) employing wave division multiplexing (WDM) hardware is implemented at each node of a multi-node fiber-based network. The ADM contains a robust protection scheme for reliability. The WDM allows...http://www.google.de/patents/US6623186?utm_source=gb-gplus-sharePatent US6623186 - Optical ethernet overlay for loop topology network
