OC levels (OC-3 to OC-768)
termISP & telecom
Stands for: SONET Optical Carrier levels and their SDH STM equivalents
The SONET Optical Carrier ladder - OC-3, OC-12, OC-48, OC-192 - every rung 51.84 Mb/s times n, with SDH's STM names for the same speeds.
OC-n means n times the 51.84 Mb/s STS-1: OC-3 at 155 Mb/s (SDH STM-1), OC-12 at 622 (STM-4), OC-48 at 2.5 Gb/s (STM-16), OC-192 at 10 Gb/s (STM-64), OC-768 at 40 Gb/s (STM-256). A 'c' suffix (OC-3c) meant concatenated - one big pipe rather than channelized subdivisions. For two decades these names WERE the speed vocabulary of carrier links and router interfaces; reading old network diagrams, RFPs, or war stories requires the ladder, even now that Ethernet names took over.
Also known as: oc-3, oc-12, oc-48, oc-192, oc-768, stm-1, stm-16, stm-64, optical carrier