Result: standard mapping
How many E1s are in an OC-48?
An OC-48 carries 1,008 E1s, per Telcordia GR-253.
1,008
E1s in an OC-48
Working
OC-48 → 48 × OC-1 (STS-1) → 21 × E1
- 48 × OC-1 (STS-1) in each OC-48 Telcordia GR-25348 × OC-1 (STS-1). Channelized OC-48 is 48 STS-1s.
- 21 × E1 in each OC-1 (STS-1) Telcordia GR-253Seven VT groups × three VT2 (E1).
- 48 OC-1s
- 48 × 21 = 1,008 E1s
Leftover capacity
423.936 Mbit/s of each OC-48 line rate (2.488320 Gbit/s) sits outside 1,008 × 2.048 Mbit/s of E1 line rate (2.064384 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 1,215, which floors to 1,215 E1s by bit rate only. The standard mapping is 1,008. Use the mapping.