Important SONET and SDH Acronyms & Terms

*** you MUST know these to follow these sections ***

North America Terms

• SONET - Synchronous Optical Network

• OC - Optical Carrier - a SONET-based data rate where OC-n = 51.84 Mbps x n 

• STS - Synchronous Transport Signal (standardized by ANSI) - a SONET-based data rate 

Europe and ROW Terms

• SDH - Synchronous Digital Hierarchy

• STM -  Synchronous Transport Module (standardized by the CCITT)

• STS-1  Synchronous Transport Signal 1: SONET logical standard that defines the framing format and signaling overhead for transmission over OC-1 optical fiber at 51.84 Mbps.

• OC-1  Optical Carrier signal 1:  SONET physical standard that defines the carrier for the STS-1 frames

• FOTS – Fiber Optic Transmission System

• STS-n  Synchronous Transport Signal "n" : (where n is an integer) SONET standards for transmission over OC-n optical fiber by multiplexing "n" STS-1 frames, (e.g., STS-3 at 155.52 Mbps STS-12 at 622.08 Mbps and STS-48 at 2.488 Gbps).

• STS-nc  Synchronous Transport Signal "n" concatenated: (where n is an integer) SONET standards for transmission over OC-n optical fiber by multiplexing "n" STS-1 frames, (e.g., STS-3 at 155.52 Mbps STS-12 at 622.08 Mbps and STS-48 at 2.488 Gbps but treating the information fields as a single concatenated payload).

• STM  Synchronous Transfer Module: STM is a basic building block used for a synchronous multiplexing hierarchy defined by the CCITT/ITU-T. STM-1 operates at a rate of 155.52 Mbps (same as STS-3).

• STM-1  Synchronous Transport Module 1: SDH standard for transmission over OC-3 optical fiber at 155.52 Mbps.

• STM-n  Synchronous Transport Module "n" : (where n is an integer) SDH standards for transmission over optical fiber (OC-'n x 3) by multiplexing "n" STM-1 frames, (e.g., STM-4 at 622.08 Mbps and STM-16 at 2.488 Gbps).

• STM-nc  Synchronous Transport Module "n" concatenated: (where n is an integer) SDH standards for transmission over optical fiber (OC-'n x 3) by multiplexing "n" STM-1 frames, (e.g., STM-4 at 622.08 Mbps and STM-16 at 2.488 Gbps, but treating the information fields as a single concatenated payload).