Nov. 7/00 High Speed Internet Technologies

The Need For SpeedTerry Foley

Rhonda HoskinsJerry GilroyJill Morgan

High Speed Internet Technology

Outline

What is DSL?

Where did DSL originate?

How does DSL work?

What types of DSL are available?

Myths and Truths about DSL

Its closest competitor

http://computingcentral.msn.com/topics/bandwidth/howfast.asp

What is DSL?

DSL – Digital Subscriber Line

Uses ordinary telephone wire

Speed varies depending on type

An “always on” service – No dial-up

One line carries both data and voice

Where Did DSL Originate

Created by Bellcore in 1989

To deliver video on-demand to compete with cable TV

Never really used for this

People noticed the potential for internet applications

How Does DSL Work

Implemented over the “last mile”

Uses digital technology

Utilizes line-coding scheme

Divides line into 3 bands

Lower for voice, Higher 2 for data

How Does DSL Work cont’d

Phone company must install special router – DSL access multiplexerThis transfers data from copper line to larger backboneCO must be approx. 18000 ft from the end user for top performanceEnd user must have special router or modem

Types Of DSL

HDSL – High-Data-Rate DSL

ADSL – Asymmetric DSL

RADSL – Rate Adaptive DSL

SDSL – Symmetric DSL

VDSL – Very-High-Rate DSL

Speeds Of Different Types

DSL Type Downstream Upstream Distance # Of LinesSpeed Speed

HDSL 2 Mbps 2 Mbps Up to 5km 2ADSL Up to 8 Mbps Up to 768 Kbps 3.6 km 1

RADSL Up to 8 Mbps Up to 768 Kbps Up to 6km 1SDSL 768 Kbps 768 Kbps 4 km 1VDSL 13, 26 or 52 Mbps 6 or 13 Mbps Up to 1.5km 1

Myths And Truths

Myth – DSL is easy to install

Truth – Technician needed to install modem and wiring

Myth – Speed of DSL

Truth – Performance is effected by electromagnetic noise and distance

Its Closest Competitor

Cable – It provides similar speeds, service and technology

Uses local TV line to give continuous connection

The Need For Speed