Result: standard mapping
How many E4s are in a STM-1?
A STM-1 carries 1 E4, per ITU-T G.707. This is a client mapping of E4 into STM-1.
1
E4 in a STM-1
Working
STM-1 → 1 × E4
- 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 E4
Leftover capacity
16.256 Mbit/s of each STM-1 line rate (155.520 Mbit/s) sits outside 1 × 139.264 Mbit/s of E4 line rate (139.264 Mbit/s). That remainder is overhead, fixed stuff or justification. It is not another whole tributary.