The optical node connects N networks to each other (where N is an integer larger than one). Each of the N networks respectively includes a first transmission path and a second transmission path. The optical node includes a switching unit that connects the first transmission path of one network of the...http://www.google.fr/patents/US7711270?utm_source=gb-gplus-shareBrevet US7711270 - Optical node and optical add/drop multiplexer
