Cisco CISCO7201 Bedienungsanleitung PDF herunterladen (Seite 8)

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PA-A6 ATM Port Adapter Installation and Configuration

OL-2672-05

Chapter 1 Overview

Additional Information

SONET Frame Fundamentals

SONET is a Layer 1 protocol that uses a layered architecture. The following illustration shows SONET’s

three layers: section, line, and path. The Section OverHead (SOH) and Line OverHead (LOH) form the

Transport OverHead (TOH), while the Path OverHead (POH) and actual payload form the Synchronous

Payload Envelope (SPE). (See Figure 1-10.)

Figure 1-10 Three SONET Layers of a SONET Frame

Each layer adds some number of overhead bytes to the SONET frame.

Table 1-5 SONET Maximum Fiber-Optic Transmission Distances

Transceiver Type Maximum Distance Between Stations

1. Table 1-5 gives typical results. Use the power budget calculations described in the following sections to determine the

actual distances.

Single-mode long reach (SML) Up to 24.8 miles (40 kilometers)

Single-mode intermediate reach (SMI) Up to 9.3 miles (15 kilometers)

Multimode (MM) Up to 1.2 miles (2 kilometers)

3 Bytes

9 rows

Section

overhead

Line

overhead

STS

87 Bytes

Transport

overhead

Payload Envelope

(SPE)

Payload

capacity

80664

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Cisco CISCO7201 Bedienungsanleitung Seite 8