Result: standard mapping
How many DS3s are in an ODU0?
An ODU0 carries 12 DS3s, per ITU-T G.709 and ITU-T G.707. This path maps STM-4 into ODU0 as a client, then follows that client's tributaries.
12
DS3s in an ODU0
Working
ODU0 → 1 × STM-4 → 4 × STM-1 → 3 × DS3
- 1 × STM-4 in each ODU0 ITU-T G.709Client mappingCBR STM-4 mapped into OPU0.
- 4 × STM-1 in each STM-4 ITU-T G.7074 × STM-1.
- 3 × DS3 in each STM-1 ITU-T G.707Three VC-3s, each able to carry a DS3.
- 1 STM-4
- 1 × 4 = 4 STM-1s
- 1 × 4 × 3 = 12 DS3s
Leftover capacity
707.328 Mbit/s of each ODU0 line rate (1.244160 Gbit/s) sits outside 12 × 44.736 Mbit/s of DS3 line rate (536.832 Mbit/s). That remainder is overhead, fixed stuff or justification. It is not another whole tributary.
By bit rate only
Dividing the line rates gives 27.81, which floors to 27 DS3s by bit rate only. The standard mapping is 12. Use the mapping.