Result: standard mapping
How many OC-48s are in an ODU4?
An ODU4 carries 40 OC-48s, per ITU-T G.709. This is a client mapping of OC-48 into ODU1.
40
OC-48s in an ODU4
Working
ODU4 → 40 × ODU1 → 1 × OC-48
- 40 × ODU1 in each ODU4 ITU-T G.70940 ODU1s, two slots each.
- 1 × OC-48 in each ODU1 ITU-T G.709Client mappingCBR OC-48, the same client rate as STM-16, mapped into OPU1.
- 40 ODU1s
- 40 × 1 = 40 OC-48s
Leftover capacity
5.261645815 Gbit/s of each ODU4 line rate (104.794445815 Gbit/s) sits outside 40 × 2.488320 Gbit/s of OC-48 line rate (99.532800 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 42.11, which floors to 42 OC-48s by bit rate only. The standard mapping is 40. Use the mapping.