OC-192 Guide

OC-192 is the SONET designation for a 10G transport signal, and STM-64 is its SDH equivalent. The two names describe the same speed in two standards families: SONET, used mainly in North America, and SDH, used mainly elsewhere. A 10G transport link carries roughly 10 gigabits per second of framed traffic, and the optics that carry it are 10G optics, which is why OC-192 appears in optical catalogues alongside Ethernet and Fibre Channel at the same speed. This guide explains the designation and where it fits.

The relationship between OC-192 and 10G Ethernet is close but not identical. Both run at about 10G, but they frame the traffic differently, and the line rate differs slightly: the SONET and SDH framing adds overhead that Ethernet framing does not, so the optical rate for OC-192 sits in a slightly different place within the 10G band. That is why a 10G module's published rate range matters. The published XFP LR model on this site, for example, states a rate range of 9.95 to 11.1Gb/s, which covers Ethernet, SDH and Fibre Channel applications, and the product page names SDH STM I-64.1 among its applications. A buyer should state the application — Ethernet, SDH or Fibre Channel — during the inquiry, so the right configuration can be confirmed.

Where does OC-192 appear in practice? In transport networks that carry traffic between cities, between carriers, and between a carrier and a large customer. In metro networks that aggregate traffic from many access links onto a high-capacity ring. In the backhaul of mobile networks, where base station traffic is gathered onto transport links. In each case the optics sit in transport equipment with XFP or similar slots, and the module must match both the slot and the framing. A module configured for Ethernet will not necessarily run a SONET or SDH link, even at the same nominal speed, because the framing and the rate differ.

The practical advice for a buyer sourcing OC-192 optics is short. State the framing — SONET OC-192 or SDH STM-64 — alongside the speed, because the two are not interchangeable labels for the same thing in every implementation. State the fiber type and the distance, as for any optical link. State the equipment the module will plug into, because transport slots differ from data slots. And confirm the configuration during the inquiry, because a module that covers several rates still needs to be set for the network it will run in.

This guide states transport practice at category level. No OC-192 module specification is stated here as a product claim, because the published XFP LR figures are stated on that model's detail page and belong to that model alone. Before ordering, confirm quantity, price and delivery time during the inquiry. Certificates are available upon request.