The rate is 10.3125 Gbit/s when the signal type is 10GE LAN. Regardless of OTU1, OTU2, and OTU3, the OTN frame structure is fixed (four rows and 4080 columns). Except the 256-column FEC area and the 16-column overhead area of OTU2, ODU2, and OPU2, the OPU2 area occupies 3808 columns. When the client-side signals are mapped into OPU2 payloads, the OPU2 payloads must be added to the 16-column fixed stuff (FS). Therefore, in the OTU2 frame structure, client-side signals occupy 3792 (3808 - 16) columns. The OTN frame frequency can be adjusted. To implement transparent transmission of all 10GE-LAN signals of 10.3125Gbit/s without any change through OTU2 frames, the OTU2e rate on the WDM side is obtained though the following formula:
3792/4080 = 10.3125/OTU2e frame rate
That is, OTU2e frame rate = 255/237 × 10.3125 kbit/s = 11.0957 Gbit/s = 11.1 Gbit/s
