Result: standard mapping
How many DS1s are in an OC-12?
An OC-12 carries 336 DS1s, per Telcordia GR-253.
336
DS1s in an OC-12
Working
OC-12 → 12 × OC-1 (STS-1) → 28 × DS1
- 12 × OC-1 (STS-1) in each OC-12 Telcordia GR-25312 × OC-1 (STS-1). Channelized OC-12 is 12 STS-1s.
- 28 × DS1 in each OC-1 (STS-1) Telcordia GR-253Seven VT groups × four VT1.5 (DS1).
- 12 OC-1s
- 12 × 28 = 336 DS1s
Leftover capacity
103.296 Mbit/s of each OC-12 line rate (622.080 Mbit/s) sits outside 336 × 1.544 Mbit/s of DS1 line rate (518.784 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 402.9, which floors to 402 DS1s by bit rate only. The standard mapping is 336. Use the mapping.