Cpos Interface Configuration; Overview; Sonet/Sdh; Cpos - 3Com MSR 50 Series Configuration Manual

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Overview

SONET/SDH

CPOS

CPOS I
NTERFACE
When configuring ATM/DSL interface, go to these sections for information you are
interested in:
"Overview" on page 539
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"Configuring a CPOS Interface" on page 544
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"Configuring an E1 Channel" on page 545
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"Configuring a T1 Channel" on page 545
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"Displaying and Maintaining CPOS Interfaces" on page 546
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"Troubleshooting CPOS Interfaces" on page 546
■
This section covers these topics:
"SONET/SDH" on page 539
■
"SDH Frame Structure" on page 540
■
"Terms" on page 540
■
"Multiplexing E1/T1 Channels to Form STM-1" on page 541
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"Calculating E1/T1 Channel Sequence Numbers" on page 541
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"Overhead Byte" on page 542
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"CPOS Interface Application Scenario" on page 543
■
Synchronous optical network (SONET), a synchronous transmission system defined
by ANSI, is an international standard transmission protocol. It adopts optical
transmission.
In SDH defined by CCIT (today's ITU-T), adoption of synchronous multiplexing and
flexible mapping allows you to add/drop low-speed tributary signals from SDH
signal without large amount of multiplexing/demultiplexing devices. This reduces
signal attenuation and device investment.
Low-speed tributary signals are called channels when they are multiplexed to form
SDH signals. CPOS, the channelized POS interface, makes full use of SDH to
provide precise bandwidth division, reduce the number of low-speed physical
interfaces on devices, enhance their redistribution capacity, and improve the
access capacity of dedicated lines.
CPOS interfaces are mainly used to enhance the devices' redistribution capacity for
low-speed access. CPOS interfaces are mainly of two rates: STM-1 (155 mbps) and
STM-16c (2.5 Gbps).
C
ONFIGURATION