Result: standard mapping
How many E0s are in an ODU0?
An ODU0 carries 7,560 E0s, per ITU-T G.709, ITU-T G.707 and ITU-T G.704. This path maps STM-4 into ODU0 as a client, then follows that client's tributaries.
7,560
E0s in an ODU0
Working
ODU0 → 1 × STM-4 → 4 × STM-1 → 63 × E1 → 30 × E0
- 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.
- 63 × E1 in each STM-1 ITU-T G.70763 VC-12 tributaries: 3 TUG-3 × 7 TUG-2 × 3 TU-12.
- 30 × E0 in each E1 ITU-T G.70430 voice channels in 32 timeslots. TS0 is framing and TS16 is channel-associated signalling.
- 1 STM-4
- 1 × 4 = 4 STM-1s
- 1 × 4 × 63 = 252 E1s
- 1 × 4 × 63 × 30 = 7,560 E0s
Leftover capacity
760.320 Mbit/s of each ODU0 line rate (1.244160 Gbit/s) sits outside 7,560 × 64 kbit/s of E0 line rate (483.840 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 19,440, which floors to 19,440 E0s by bit rate only. The standard mapping is 7,560. Use the mapping.