Result: standard mapping
How many E4s are in an ODU0?
An ODU0 carries 4 E4s, per ITU-T G.709 and ITU-T G.707. This path maps STM-4 into ODU0; E4 into STM-1 as a client, then follows that client's tributaries.
4
E4s in an ODU0
Working
ODU0 → 1 × STM-4 → 4 × STM-1 → 1 × E4
- 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.
- 1 × E4 in each STM-1 ITU-T G.707Client mappingAsynchronous E4 mapped into the C-4 / VC-4. This client holds 64 E1s internally; the VC-12 tributary count of an STM-1 is 63.
- 1 STM-4
- 1 × 4 = 4 STM-1s
- 1 × 4 × 1 = 4 E4s
Leftover capacity
687.104 Mbit/s of each ODU0 line rate (1.244160 Gbit/s) sits outside 4 × 139.264 Mbit/s of E4 line rate (557.056 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 8.93, which floors to 8 E4s by bit rate only. The standard mapping is 4. Use the mapping.