Result: standard mapping
How many STM-16s are in an OTU3?
An OTU3 carries 16 STM-16s, per ITU-T G.709. This is a client mapping of STM-16 into ODU1.
16
STM-16s in an OTU3
Working
OTU3 → 1 × ODU3 → 16 × ODU1 → 1 × STM-16
- 1 × ODU3 in each OTU3 ITU-T G.709The OTU3 frame carries exactly one ODU3.
- 16 × ODU1 in each ODU3 ITU-T G.70916 ODU1s, two slots each.
- 1 × STM-16 in each ODU1 ITU-T G.709Client mappingCBR STM-16 mapped into OPU1.
- 1 ODU3
- 1 × 16 = 16 ODU1s
- 1 × 16 × 1 = 16 STM-16s
Leftover capacity
3.205293559 Gbit/s of each OTU3 line rate (43.018413559 Gbit/s) sits outside 16 × 2.488320 Gbit/s of STM-16 line rate (39.813120 Gbit/s). That remainder is overhead, fixed stuff or justification. It is not another whole tributary.
By bit rate only
Dividing the line rates gives 17.28, which floors to 17 STM-16s by bit rate only. The standard mapping is 16. Use the mapping.