SONET - Synchronous Optical Network

Synchronous Optical Network

SONET is the American National Standards Institute standard for synchronous data transmission on optical media. The international equivalent of SONET is synchronous digital hierarchy (SDH). Together, they ensure standards so that digital networks can interconnect internationally and that existing conventional transmission systems can take advantage of optical media through tributary attachments.

SONET provides standards for a number of line rates up to the maximum line rate of 9.953 gigabits per second (Gbps). Actual line rates approaching 20 gigabits per second are possible. SONET is considered to be the foundation for the physical layer of the broadband ISDN (BISDN).

Asynchronous transfer mode runs as a layer on top of SONET as well as on top of other technologies.

SONET defines a base rate of 51.84 Mbps and a set of multiples of the base rate known as "Optical Carrier levels (OCx)."

SONET/SDH定義了一組在光纖上傳輸光信號的速率和格式，通常統稱為光同步數位傳輸網，是寬頻綜合數位網B-ISDN的基礎之一。SONET/SDH採用TDM技術，是同步系統，由主時鐘控制，精度10^-9).兩者都用於骨幹網傳輸。是對沿襲應用的准同步數位系列PDH (Plesiochronous Digital Hierarchy)的一次革命。