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Broadband Technology Cable modem & DSL. Cosc 513 Professor: Dr. Anvari By Ching-Jen Hsueh 106003. Broadband Technology. Contents I. Introduction II. The Advantages of Dial-up modems III. The Advantages of Broadband Connection IV. Cable Modem V. DSL VI. Security Issues VII. Summary - PowerPoint PPT Presentation
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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!