Result: standard mapping
How many DS1s are in an OC-1?
An OC-1 carries 28 DS1s, per Telcordia GR-253.
28
DS1s in an OC-1
Working
OC-1 (STS-1) → 28 × DS1
- 28 × DS1 in each OC-1 (STS-1) Telcordia GR-253Seven VT groups × four VT1.5 (DS1).
- 28 DS1s
Leftover capacity
8.608 Mbit/s of each OC-1 line rate (51.840 Mbit/s) sits outside 28 × 1.544 Mbit/s of DS1 line rate (43.232 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 33.57, which floors to 33 DS1s by bit rate only. The standard mapping is 28. Use the mapping.