OC12 Internet Access Service Providers

OC12 is the abbreviated term for Optical Carrier level 12, used to specify the speed level of fiber optic networks. Its speed is measured through SONET (Synchronous Optical Network) standards.

OC-12 circuits work as a reliable fiber optic backbone for large networks with large IP bandwidth needs, VoIP / Voice over IP, Video Conferencing, and Internet applications.

OC-12 requires low maintenance, but can take longer to upgrade than Gigabit Ethernet when adding bandwidth rings to increase speeds and capacity to a higher level.

OC12 is most often made up of what is called a "SONET ring" to maintain it' reliability during it' high speed transmissions.

A common method of back up used with OC-12 ring is called a "bi-directional ring topology." This bi-directional ring is a physical topology which deploys two sets of fiber strands. The ring is a physical fiber ring more resembling an oval shaped loop.

The first strand to an OC12 connection is for sending and receiving. The second strand will reroute traffic from the original OC12 transmission in another direction should the first strand break or malfunction.

Bi-directional ring topology help ensures constant reliability within an OC-12 fiber based network.

The primary function is to take, synchronize, and transport data, video, and voice at the speed of 622 Mbps reliably. Common sources of this data include ATM switches, T1 and T3 multiplexers, and large IP networks.

STS-12 is the abbreviated term standing for Synchronous Transport Signal level 12. STS and SONET OC carry the same electrical equivalent; therefore STS-12 is the equivalent to SONET level OC-12.

STS-12 is an optical carrier frame consisting of the following characteristics:

SPE (Synchronous Payload Envelope), SOH (Section Overhead), POH (Path Overhead), and LOH (Line Overhead).

SPE is the electronic envelope that carries the data over the OC12 otherwise known as the Payload.

SOH maintains all the links within OC-12 while relaying line status to the end user. The information within SOH includes the status of transported data, the notification of messages, as well as alarm levels.

POH is responsible for the functionality of the data envelope in OC-12 while in transit. Such functionality includes vital information for the management of end-to-end networks. POH travels within the data envelope until the data is de-multiplexed through multiplexing equipment.

LOH controls the reliability transit of the data over an OC12 line.

LOH and SOH combined on a SONET OC12 network create what is referred to as TOH (Transport Overhead). TOH is one of the elements responsible for signaling and control over OC12 network lines.

The Four OC12 Layers

1. Photonic Layer - This layer of an OC12 converts transmitted electrical signals that usually travel via copper into optical signals then transfers them back into electrical signals at the end of the transmission.

2. Section Layer - This layer monitors the condition and progress of the OC-12 signal in route to and from signal amplifiers and SONET hardware.

3. Line Layer - This layer monitors and provides administration of multiplexers as well as provides synchronization of multiple signals. Through this synchronization, the OC-12 is able to put all the signals into one stream of traffic for high speed transfer.

4. Path Layer - Assembles and disassembles transmitted data and voice into frames.

OC12 Speed & Capacity

OC12 Availability & Pricing: