Result: standard mapping
How many STM-256s are in an OTU3?
An OTU3 carries 1 STM-256, per ITU-T G.709. This is a client mapping of STM-256 into ODU3.
1
STM-256 in an OTU3
Working
OTU3 → 1 × ODU3 → 1 × STM-256
- 1 × ODU3 in each OTU3 ITU-T G.709The OTU3 frame carries exactly one ODU3.
- 1 × STM-256 in each ODU3 ITU-T G.709Client mappingCBR STM-256 mapped into OPU3.
- 1 ODU3
- 1 × 1 = 1 STM-256
Leftover capacity
3.205293559 Gbit/s of each OTU3 line rate (43.018413559 Gbit/s) sits outside 1 × 39.813120 Gbit/s of STM-256 line rate (39.813120 Gbit/s). That remainder is overhead, fixed stuff or justification. It is not another whole tributary.