Optical channel overhead information for individual optical channels is transported in a message based channel on an optical supervisory channel. Specifically, this is realized by obtaining performance monitoring, and/or performance measurement, and/or operations, and/or administration, and/or maintenance...http://www.google.com/patents/US6594047?utm_source=gb-gplus-sharePatent US6594047 - Apparatus and method for providing optical channel overhead in optical transport networks
