Result: standard mapping
How many E3s are in an OTU2?
An OTU2 carries 192 E3s, per ITU-T G.709 and ITU-T G.707. This path maps STM-64 into ODU2 as a client, then follows that client's tributaries.
192
E3s in an OTU2
Working
OTU2 → 1 × ODU2 → 1 × STM-64 → 64 × STM-1 → 3 × E3
- 1 × ODU2 in each OTU2 ITU-T G.709The OTU2 frame carries exactly one ODU2.
- 1 × STM-64 in each ODU2 ITU-T G.709Client mappingCBR STM-64 mapped into OPU2.
- 64 × STM-1 in each STM-64 ITU-T G.70764 × STM-1.
- 3 × E3 in each STM-1 ITU-T G.707Three VC-3s, each carrying an E3.
- 1 ODU2
- 1 × 1 = 1 STM-64
- 1 × 1 × 64 = 64 STM-1s
- 1 × 1 × 64 × 3 = 192 E3s
Leftover capacity
4.110569316 Gbit/s of each OTU2 line rate (10.709225316 Gbit/s) sits outside 192 × 34.368 Mbit/s of E3 line rate (6.598656 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 311.6, which floors to 311 E3s by bit rate only. The standard mapping is 192. Use the mapping.