Result: standard mapping
How many DS1s are in an OC-3?
An OC-3 carries 84 DS1s, per Telcordia GR-253.
84
DS1s in an OC-3
Working
OC-3 → 3 × OC-1 (STS-1) → 28 × DS1
- 3 × OC-1 (STS-1) in each OC-3 Telcordia GR-2533 × OC-1 (STS-1). Channelized OC-3 is 3 STS-1s.
- 28 × DS1 in each OC-1 (STS-1) Telcordia GR-253Seven VT groups × four VT1.5 (DS1).
- 3 OC-1s
- 3 × 28 = 84 DS1s
Leftover capacity
25.824 Mbit/s of each OC-3 line rate (155.520 Mbit/s) sits outside 84 × 1.544 Mbit/s of DS1 line rate (129.696 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 100.72, which floors to 100 DS1s by bit rate only. The standard mapping is 84. Use the mapping.