SONET Graphical Overview

Introduction

This document provides an overview of Synchronous Optical Network (SONET), represented in images.

Note:  Tables and diagrams courtesy of JDS Uniphase Corporation

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

This document is not restricted to specific software and hardware versions.

Conventions

Refer to Cisco Technical Tips Conventions for more information on document conventions.

SONET Overview

This section provides an overview of SONET in a graphical format.

The SONET Link

Figure 1 shows what a SONET link looks like.

Figure 1 – A SONET Link

STS-1 Frames

Figure 2 shows the Synchronous Transport Signal level 1 (STS-1) frame structure.

Figure 2 – STS-1 Frame Structure

STS-1 SONET Overhead

Figure 3 shows the STS-1 Transport and Path Overhead (SONET Overhead).

Figure 3 – STS-1 Transport and Path Overhead

OC-12 Concatenation

Figure 4 looks at OC-12 concatenation.

Figure 4 – OC-12 Concatenation

SONET Hierarchy

Figure 5 displays the SONET hierarchy.

Figure 5 – SONET Hierarchy

SONET Maintenance Interactions

Figure 6 shows how SONET maintenance interactions appear.

Figure 6 – SONET Maintenance Interactions

Alarms and Detection Criteria

Table 1 lists what the alarms mean, and their detection criteria.

Table 1 – Meaning of Alarms and their Detection Criteria

STS-1 SOH, LOH, POH and VT POH Bytes

Figure 7 and Figure 8 provide a description of all the bytes from STS-1 SOH, Line OverHead (LOH), Path OverHead (POH) and Virtual Tributary Path OverHead (VT POH).

Figure 7 – SOH Section Overhead

Figure 8 – LOH Line Overhead

Related Information

• Optical Product Support Pages
• Technical Support & Documentation - Cisco Systems