…SONET/SDH—to be carried over a single Optical Transport Unit (OTU) frame, either OTU-1 at 2.7 Gb/s, OTU-2 at 10.7 Gb/s, OTU-3 at 43 Gb/s, or OTU-4 at 112 Gb/s. In addition to multiplexing services, OTN adapts to ever-changing customer requirements and provides more effective optical network management…

…  It was 4 years from the 100G Call For Interest (CFI) to approved standard in IEEE.  During that time ITU-T also developed the standard for OTU4 to carry 100GbE so that as the initial 100GigE modules became available, it was also possible to transport 100GbE in long haul links.  If the two…