Transcript DSL - Digital Subscriber Line An Overview

DSL - Digital
Subscriber Line
An Overview
Presented by Team 1
November 17, 2001
ADSL
Contents
Origins of ADSL
 Definition
 ADSL Standards – US
 Typical ADSL Installation
 Technical Description
 Evaluation
 A View to the Future

Origins of ADSL
Availability of Cabling
 Need for Faster
Communication
 Internet EXPLOSION!
 Expense of ISDN
 Emergence of
Telecommuting
 New Applications

Definition

Asymmetric DSL (ADSL)
“a modem technology that
converts existing twisted pair
telephone lines into access
paths for multimedia and high
speed data communications.”
Source:
"ADSL Tutorial: Twisted Pair
Access to the
Information Highway,"
http://www.adsl.com/aboutdsl/adsl_tutorial
.html
ADSL Standards - US

ANSI T1E1 working group

ITU-T Study Group 15

ADSL Forum
– Recommends end-to-end
ADSL architectures, including
the higher layer protocols
needed to make ADSL systems
useful products.
Typical ADSL
Installation
Technical Description
General

Frequency: Above 25kHz
– POTS

Below 4kHz
Modulation:
– DMT
– CAP
Discrete Multi-tone
Carrier-less Amplitude/
Phase Modulation
– QAM Quadrature Amplitude
Modulation

Medium:
Unshielded
Twisted Pair
– 24 AWG (~.5m)
– 26 AWG (~.4m)
Technical Description
Transmission Rates

Class I
– 6,000 ft

Class II
– 8,000 ft

Class III
– 12000 ft
– 9000 ft

Class IV
– 18000 ft
6,175 Mb/s
26 AWG loops
4.632 Mb/s
26 AWG
3.088 Mb/s
24 AWG
26 AWG
1.544 Mb/s
26 AWG
Installation
Components
Central Office
.
Public Switched
Voice Network
Combined
Voice and IP Data
To
Internet
DSLAM
High Speed
Data Switch
IP Data
Copper Wire
IP Data
Splitter
ADSL Modem
ATU-R
Voice
Home PC
w/Ethernet NIC
& IP Address
Analog
Modem
Telephone
Fax
Source: Paradyne, Inc.
Laptop computer
ADSL - An Evaluation
Targeted Marketplace
 Chief Competitors
 Price Considerations
 Economy
 Other Barriers

ADSL - A View to the
Future

Interim Strategy
– Copper
– Cable
– Fiber
Telecommunications ShakeOut
 Emergence of True Wireless
Solutions
