Result: standard mapping
How many STM-16s are in an OTU2?
An OTU2 carries 4 STM-16s, per ITU-T G.709. This is a client mapping of STM-16 into ODU1.
4
STM-16s in an OTU2
Working
OTU2 → 1 × ODU2 → 4 × ODU1 → 1 × STM-16
- 1 × ODU2 in each OTU2 ITU-T G.709The OTU2 frame carries exactly one ODU2.
- 4 × ODU1 in each ODU2 ITU-T G.709Four ODU1s. Each ODU1 takes two of the eight 1.25 Gbit/s tributary slots.
- 1 × STM-16 in each ODU1 ITU-T G.709Client mappingCBR STM-16 mapped into OPU1.
- 1 ODU2
- 1 × 4 = 4 ODU1s
- 1 × 4 × 1 = 4 STM-16s
Leftover capacity
755.945316 Mbit/s of each OTU2 line rate (10.709225316 Gbit/s) sits outside 4 × 2.488320 Gbit/s of STM-16 line rate (9.953280 Gbit/s). That remainder is overhead, fixed stuff or justification. It is not another whole tributary.