Result: standard mapping
How many DS3s are in an OC-12?
An OC-12 carries 12 DS3s, per Telcordia GR-253.
12
DS3s in an OC-12
Working
OC-12 → 12 × OC-1 (STS-1) → 1 × DS3
- 12 × OC-1 (STS-1) in each OC-12 Telcordia GR-25312 × OC-1 (STS-1). Channelized OC-12 is 12 STS-1s.
- 1 × DS3 in each OC-1 (STS-1) Telcordia GR-253Asynchronous DS3 mapping into the STS-1 synchronous payload envelope.
- 12 OC-1s
- 12 × 1 = 12 DS3s
Leftover capacity
85.248 Mbit/s of each OC-12 line rate (622.080 Mbit/s) sits outside 12 × 44.736 Mbit/s of DS3 line rate (536.832 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 13.9, which floors to 13 DS3s by bit rate only. The standard mapping is 12. Use the mapping.