Result: standard mapping
How many E1s are in an ODU2?
An ODU2 carries 4,032 E1s, 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.
4,032
E1s in an ODU2
Working
ODU2 → 1 × STM-64 → 64 × STM-1 → 63 × E1
- 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.
- 63 × E1 in each STM-1 ITU-T G.70763 VC-12 tributaries: 3 TUG-3 × 7 TUG-2 × 3 TU-12.
- 1 STM-64
- 1 × 64 = 64 STM-1s
- 1 × 64 × 63 = 4,032 E1s
Leftover capacity
1.779737924 Gbit/s of each ODU2 line rate (10.037273924 Gbit/s) sits outside 4,032 × 2.048 Mbit/s of E1 line rate (8.257536 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 4,901.01, which floors to 4,901 E1s by bit rate only. The standard mapping is 4,032. Use the mapping.