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.
Concatenated STS (OC) frames carry only one column of path overhead because they cannot be divided into finer granularity signals.
OC-12 lines were commonly used by ISPs as wide area network (WAN) connections, or connecting xDSL customers to a larger internal network [3] This connection speed was popular with mid-sized (below Tier 2) internet customers, such as web hosting companies or smaller ISPs buying service from larger ones.
A standardized variant of 10 Gigabit Ethernet, called WAN PHY, is designed to inter-operate with OC-192 transport equipment while the common version of 10 Gigabit Ethernet is called LAN PHY (which is not compatible with OC-192 transport equipment in its native form).
[4][5] On October 23, 2008, AT&T announced the completion of upgrades to OC-768 on 80,000 fiber-optic wavelength miles of their IP/MPLS backbone network.
Infinera made a field trial demonstration data transmission on a live production network involving the service transmission of a 40 Gbit/s OC-768/STM-256 service over a 1,969 km terrestrial network spanning Europe and the U.S.
In November 2008, an OC-768 connection was successfully brought up on the TAT-14/SeaGirt transatlantic cable,[7] the longest hop being 7,500 km.