Result: standard mapping
How many DS2s are in an ODU0?
An ODU0 carries 84 DS2s, per ITU-T G.709, ITU-T G.707 and ANSI T1.107. This path maps STM-4 into ODU0 as a client, then follows that client's tributaries.
84
DS2s in an ODU0
Working
ODU0 → 1 × STM-4 → 4 × STM-1 → 3 × DS3 → 7 × DS2
- 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.
- 7 × DS2 in each DS3 ANSI T1.107M13 multiplex: seven DS2s.
- 1 STM-4
- 1 × 4 = 4 STM-1s
- 1 × 4 × 3 = 12 DS3s
- 1 × 4 × 3 × 7 = 84 DS2s
Leftover capacity
713.952 Mbit/s of each ODU0 line rate (1.244160 Gbit/s) sits outside 84 × 6.312 Mbit/s of DS2 line rate (530.208 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 197.11, which floors to 197 DS2s by bit rate only. The standard mapping is 84. Use the mapping.