Result: standard mapping
How many DS1s are in an OC-768?
An OC-768 carries 21,504 DS1s, per Telcordia GR-253.
21,504
DS1s in an OC-768
Working
OC-768 → 768 × OC-1 (STS-1) → 28 × DS1
- 768 × OC-1 (STS-1) in each OC-768 Telcordia GR-253768 × OC-1 (STS-1). Channelized OC-768 is 768 STS-1s.
- 28 × DS1 in each OC-1 (STS-1) Telcordia GR-253Seven VT groups × four VT1.5 (DS1).
- 768 OC-1s
- 768 × 28 = 21,504 DS1s
Leftover capacity
6.610944 Gbit/s of each OC-768 line rate (39.813120 Gbit/s) sits outside 21,504 × 1.544 Mbit/s of DS1 line rate (33.202176 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 25,785.69, which floors to 25,785 DS1s by bit rate only. The standard mapping is 21,504. Use the mapping.