<P> Optical Carrier classifications are based on the abbreviation OC followed by a number specifying a multiple of 51.84 Mbit / s: n × 51.84 Mbit / s => OC - n . For example, an OC - 3 transmission medium has 3 times the transmission capacity of OC - 1 . </P> <P> OC - 1 is a SONET line with transmission speeds of up to 51.84 Mbit / s (payload: 50.112 Mbit / s; overhead: 1.728 Mbit / s) using optical fiber . </P> <P> OC - 3 is a network line with transmission data rate of up to 155.52 Mbit / s (payload: 148.608 Mbit / s; overhead: 6.912 Mbit / s, including path overhead) using fiber optics . Depending on the system OC - 3 is also known as STS - 3 (electrical level) and STM - 1 (SDH). </P> <P> OC - 3c ("c" stands for "concatenated") concatenates three STS - 1 (OC - 1) frames into a single OC - 3 look alike stream . The three STS - 1 (OC - 1) streams interleaved with each other such that the first column is from the first stream, the second column is from the second stream, and the third is from the third stream . Concatenated STS (OC) frames carry only one column of path overhead because they cannot be divided into finer granularity signals . Hence, OC - 3c can transmit more payload to accommodate a CEPT - 4 139.264 Mbit / s signal . The payload rate is 149.76 Mbit / s and overhead is 5.76 Mbit / s . </P>

What is the speed of an oc-3 connection