OC-3, short for Optical Carrier Level 3, is a telecommunications standard used to transmit data over optical fiber networks. It belongs to the SONET (Synchronous Optical Networking) hierarchy, which is a standardized multiplexing protocol used in high-speed fiber optic networks. OC-3 is designed to provide high-speed data transmission with a specific data rate and frame structure.

Key features of OC-3:

  1. Data Rate: OC-3 operates at a data rate of approximately 155.52 megabits per second (Mbps). This data rate is achieved by multiplexing lower-speed signals together.
  2. Frame Structure: OC-3 frames are organized into synchronous optical packets. Each frame contains a fixed number of bytes, which include payload data as well as overhead information used for synchronization, error detection, and control.
  3. Transmission Medium: OC-3 is typically used for transmitting data over optical fiber cables, allowing for high-speed and long-distance data transmission.
  4. Application: OC-3 was commonly used in telecommunications networks to provide high-speed connections for various applications, including internet access, voice communication, and data transfer.
  5. Multiplexing: OC-3 can be used to multiplex multiple lower-speed signals into a single high-speed OC-3 stream. This allows network operators to efficiently utilize the available bandwidth.
  6. SONET Hierarchy: OC-3 is part of the SONET hierarchy, which includes different levels of optical carriers with varying data rates. OC-3 is equivalent to STM-1 (Synchronous Transport Module level 1) in the SDH (Synchronous Digital Hierarchy) standard.
  7. Upgrade Paths: Higher-level optical carriers, such as OC-12 (622.08 Mbps) and OC-48 (2.488 Gbps), provide increased data rates and are often used when higher bandwidth is required.
  8. Legacy: While OC-3 was widely used in the past, newer technologies and standards, such as Ethernet over optical networks, have become more prevalent for high-speed data transmission.

It’s important to note that while OC-3 was a significant advancement in its time, modern telecommunications networks have transitioned to more advanced technologies and higher data rates to meet the increasing demands for bandwidth and speed.