Asymmetric Digital Subscriber Line
Tutorial Slide Show
Tutorial Outline
 What Is ADSL ?
 What Can ADSL Do ?
 How Does It Work ?
 Architectural Options
 Status of the Technology
 The Future
ADSL Equipment
Standard Telephone Lines
Central Office Building
Residential
Customer
ADSL Rack
of Line Cards
Customer
Premises
Equipment
Remote ADSL
Unit
Data & Telephony on One Line
Data as ATM Cells &/or IP Packets
TV
Fast
Internet
All in Addition to Existing Analogue Telephony
“Evolution of Digital Access”
Pure Fibre
Hybrid Fibre/Copper
FTTH
Enhanced
Copper
FTTx +
VDSL
Today
ADSL
Voiceband
Modem
ISD
N
“Tomorrow’s Network” : ADSL
Video Servers
ADSL
Internet
Broadband
Network
1.5 to 8Mbit/s
9.6 to 640kbit/s
Telephone
Network
Live
Broadcast
Typical Network Construction
Central Office
Street Cabinet
Feeder Network
Distribution Network
Underground
Feed
Overhead
Feed
Next Topic
 What Is ADSL ?
 What Can ADSL Do ?
 How Does It Work ?
 Architectural Options
 Status of the Technology
 The Future
ADSL Applications

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Internet Access, etc.
LAN Access (Teleworking)
Distance Learning
Broadcast TV
Home Shopping
Video On Demand
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What Is ADSL ?
What Can ADSL Do ?
How Does It Work ?
Architectural Options
Status of the Technology
The Future
How Does ADSL Work?
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Functional Elements
Use of Bandwidth
Channel Separation & POTS Splitter
Transmission Methods
 Discrete Multi-tone Modulation (DMT)
 Quadrate Amplitude Modulation (QAM)
 Carrierless Amplitude/phase
Modulation (CAP)
ADSL Modem Structure
Mbit/s
kbit/s
Mbit/s
ADSL
Modem
ADSL
Modem
Line
POTS
Filter
POTS
Filter
POTS
Linecard
Exchange End
Customer End
kbit/s
ADSL Modem Functions
Digital
Interface
Transmission Convergence
Physical Media Dependent
Rates/multiplexing
Forward Error Control (FEC)
Framing/mapping
Protocol processing
OAM processing
Line Code (modulation)
Initialisation
POTS splitter/interface
Scrambler/descrambler
Base EOC functions
Alternatives
Alternatives
Bit Synchronous (STM)
Packet Mode
ATM Mode
DMT
QAM
CAP
Baseband
Line
Interface
Growth in Bandwidth Utilization
VDSL
~1997/8?
Time
ADSL
~1994
~1990
~1986
HDSL
ISDN
~0.1 MHz
~0.5 MHz
~1 MHz
Bandwidth (MHz)
10+ MHz
Next Topic
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What Is ADSL ?
What Can ADSL Do ?
How Does It Work ?
Architectural Options
Status of the Technology
The Future
Data-Centric Architecture
10 base T
Ethernet
CPE
ADSL
or PC Remote
10 base T
Ethernet
ADSL
Linecard
45 or 155
Mbit/s
Ethernet
Hub/Switch
Router
10 base T
or
100 base T
ATM
or FR
ISP
Telecom-Centric
Architecture
ATM
e.g. 25 Mbit/s
CPE
e.g. PC
or STB
ADSL
Remote
155 Mbit/s
fibre
ADSL
Linecard
ADSL
Access
Mux
ATM
ISP
Next Topic
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What Is ADSL ?
What Can ADSL Do ?
How Does It Work ?
Architectural Options
Status of the Technology
The Future
Status of ADSL Technology
 Equipment
 Standards
 Trials
ADSL Equipment Trends
 More Choice of Transceiver Chips and
Equipment
 Increased Transceiver Integration
 More Transceivers Per Line Card and
Equipment Rack
 More Customers Per Exchange Transceiver
 Faster Transmission Speeds
 Increased Embedded Internetworking
Functionality
Standards and
Recommendations
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ANSI
ETSI
ADSL FORUM
DAVIC
ATM FORUM
ITU
ADSL Activities
Throughout the World
ADSL Activities in the USA
ADSL Activities in Asia & Australasia
ADSL Activities in Europe
Next Topic
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What is ADSL ?
What can ADSL do ?
How does it work ?
Architectural Options
Status of the technology
The Future
Broadband Network
Broadband Switch Network (eg. ATM)
Service Providers
High-Capacity Backbone Links
Servers
&
Billing
Operational
Support System
ADSL
Access Network
New Optical
Cable
Local Exchange
VDSL
POTS
“Evolution of Digital Access”
Pure Fibre
Hybrid Fibre/Copper
FTTH
Enhanced
Copper
FTTx +
VDSL
Today
ADSL
Voiceband
Modem
ISD
N
Asymmetric Digital Subscriber Line
Introduction Slide Show
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