Broadband TechnologyCable modem & DSL

Cosc 513Professor: Dr. Anvari

By Ching-Jen Hsueh

106003

Broadband Technology

ContentsI. Introduction

II. The Advantages of Dial-up modems

III. The Advantages of Broadband Connection

IV. Cable Modem

V. DSL

VI. Security Issues

VII. Summary

VIII. Reference

Broadband Technology

Introduction

1. Broadband Technology A kind of wide-spread, high-speed Internet access

2. Broadband Connections Cable model, DSL (ADSL, SDSL), T1& ISDN, and Satellite

Broadband Technology

Advantages of Dial-up modems:

1. Dial-up is cheap and everywhere a. cost free~$30 b. no distance limitation2. An unwired PC is safer

Broadband Technology

Advantages of Broadband Connections:

1. Broadband Internet service is “Always-on” You don’t have to dial in your ISP’s server, just lunch your browser

and you’re there.

2. Broadband Internet service is faster Cable and DSL connections generally deliver an average min of

around 150 Kbps and max 1~2 Mbps, versus the max of 53.3 Kbps for dial-up Internet services.

Broadband Technology

Disadvantages of Broadband Connections:

1. Broadband does not well spread2. Security issues3. Cost

Cable Modem

• Cable access is the most widely available and most commonly used broadband technology in U.S.

• Cable Web access is faster than dial-up and less complex to install than DSL

• Cable modems work via a 6-MHz channel slot with the cable signal to deliver burst download speeds of up to 5 Mbps.

Cable Modem

Cable ModemCost $40~$50 a month

$200~$300 installation feeDownstream200Kbps~1.2Mbps

(Theoretical Max 7Mbps)Upstream 100~200Kbps

Subscribers Estimated in 2000: 3.4millionEstimated in 2004: 13.7million

Cable modem

Features of Cable Modem:1. Shared bandwidth2. Upload speed is lower than download

speed3. Available in residential areas, often not in

downtown or commercial areas

Cable Modem

DSL(Digital Subscriber Line)

• DSL is the second –most-popular broadband service in U.S., trailing cable modem access

• DSL delivers digital data through phone lines• DSL boasts faster connection times, high

throughput, and cheaper subscription costs• DSL is available in metropolitan areas and their

surrounding suburbs.

DSL(Digital Subscriber Line)

Downstream Speed Upstream Speed Distance Limitation

ADSL Asymmetric 144Kbps~2.2Mbps 90Kbps~640Kbps 18,000 feet

ADSL(G.Lite) Asymmetric 1.5Mbps 384Mbps 22,000 feet

SDSL Symmetric 160Kbps~2.3Mbps 160Kbps~2.3Mbps 22,000 feet

HDSL Symmetric 1.544Mbps 1.544Mbps 12,000 feet

IDSL Symmetric 144Kbps 144Kbps Max 35,000 feet

VDSL Asymmetric 13~52Mbps 1.5~2.3Mbps 4,500 feet

ADSL( Asymmetric Digital Subscriber Line)

1. Asymmetric data transmission Different downstream and upstream

2. The farther the line, the slower the rate3. You phone line does double duty Use different frequency for voice and data

ADSL( Asymmetric Digital Subscriber Line)ADSL

Cost $40~$80 a month$200~$400 installation fee

Downstream 144Kbps~2.2Mbps(Theoretical Max 8Mbps)

Upstream 90~640KbpsSubscribers Estimated in 2000: 1.97million

Estimated in 2004: 12.2million

Security of Broadband

1. “Always on” access means always exposed

2. Hardware protection NAT (Network Address Translation)

3. Software protection Firewall software such as ZoneAlarm pro,Norton

Personal Firewall

SummaryADSL Cable Modem

Cost $40~$80 a month $40~$50 a month$200~$400 installation fee $200~$300 installation fee

Downstream 144Kbps~2.2Mbps 200Kbps~1.2Mbps(Theoretical Max 8Mbps) (Theoretical Max 7Mbps)

Upstream 90~640Kbps 100~200KbpsSubscribers Estimated in 2000: 1.97million Estimated in 2000: 3.4million

Estimated in 2004: 12.2million Estimated in 2004: 13.7millionAdvantages Dedicated service Always-on

(not shared) No distance limitationHigher availablity

DisadventagesLimitation in the distance from CO Shared bandwidthSecurity issues

Broadband Technology

Reference1. Computer Networks 3rd edition By Andrew S. Tanenbaum2. www.pcworld.com3. www.verizon.com4. www.excite.com5. www.sisco.com6. www.lucent.com7. www.3com.com8. www.com21.com9. www.zonelabs.com10. www.zonealarm.com11. www.norton.com

Broadband Technology

The End

Thank you!