Transcript Chapter 10

MIS 430 – Chapter Ten
How The Internet Works
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I. How the Internet
Works
• Structure: Hierarchical (Fig 10.1 p.334)
– National ISP (Sprint, Ameritech)
• NAP: Network Access Point
– Regional ISP (Verizon, BellSouth, Earthlink)
• MAE: Metropolitan Area Exchange
– Local ISP (ABCS, Joink, ISU)
– Customer (You!)
• Some large customers (e.g., IU) are also
Local ISPs with thousands of customers
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Structure
• Who owns the Internet?
– No longer the US government
– Internet=Network of Networks
• Charges
– End customer pays only for the
connection, not the data transferred
(this could change)
– National ISPs charge regional ISPs,
Regional ISP charges local ISP, etc.
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Connecting to an ISP
• See figure 10-2 p. 335: ISP Point of
Presence: collapsed BN
– For individuals: dial-up PPP via telephone to
modem pool or broadband (DSL/cable)
– Companies: T1, T3, OC-3, ATM, etc.
• Remote Access Server (RAS) is
authentication device: user name & PW
– ISU uses Unix and Kerberos security software
• Note: ISP must also connect to the
Internet (NAP)
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Mgt Focus 10-1: Chicago
NAP
• One of busiest NAPs in the world!
– http://nap.aads.net/main.html
– SBC operates this NAP web site for
over 140 ISP customers
– Cost is $3900/mo (DS3) plus leased line
to Chicago NAP from their closest POP
• Cisco ATM switches handle > 3.0
Gbps traffic at peak times
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National ISPs
• See fig 10-4 p. 338 for Sprint North
American Internet backbone
– Sprint runs at OC-12 and plans to move some
circuits to OC-192 (10 Gbps)
• Some run at OC-768 (80 Gbps) with some
planning for OC-3072 (160 Gbps)
• http://www.caida.org/tools/visualization/
mapnet/ click Run Mapnet and then choose
ISP to see net
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II. Internet Access
Technologies
• DSL: Digital Subscriber Line (several stds)
– See fig 10-5 p. 339 for DSL architecture:
point to point
– Uses regular phone line that must be split into
3 channels via FDM: Voice, Download, Upload
• either outside house or at each telephone device
– DSL “modem” connects inside via RJ-45 cable
(or USB on some units)
– Some DSL routers also do DSL modem work
(like my new Westell 327w)
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Types of DSL
• ADSL=Asymmetric DSL (diff up and down)
– Tradeoff between speed and distance
– T1 (G.Lite)
• Distance: 18,000 feet (~3 miles)
• Max speed: 1.5 Mbps down, 384 Kbps up
– T2: Distance 12,000 feet, speed up to 6.1 Gbps down
• VDSL Very High Data Rate DSL via Fiber Optic
– <4500 feet (13 Mbps) down to 1000 feet (55 Mbps)
– Upstream rates are lower
• DSL Lite: future, splitterless, therefore easier to
install ; one-third speed of DSL and cheaper 
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DSL References
• www.adsl.com DSL Forum (drill down)
• www.verizon.net - Local DSL info
Package
$35
1.5 M 500 K
down upload
Package 2
$30
1.5 M 500 K
1st month free if
ordered online; $30
If ordered with
Verizon calling package
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Cable Modems
• Digital service offered by cable TV firms
– Std: DOCSIS for shared multi-point service
serving 300-1000 cable customers (not all
data)
– See fig 10-8 p. 342 for architecture: line
splitter like DSL (-> TV and -> cable modem not
DSL)
• Coaxial cable to customer; fiber upstream
• All messages go to all computers on the circuit
• Requires massive rebuilding of cable TV system
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Cable Modems
• Cable modem speeds: faster than DSL
– Downstream: 27-55 Mbps; usually 1.5-2 Mbps
– Upstream: 2-10 Mbps; usually 0.2-2 Mbps
• Many standards exist; not yet widespread
• Terre Haute –local cable modem service
just starting RoadRunner $45/month +
installation
– http://www.rr.com/rdrun/
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Fixed Wireless
• Wireless DSL: up to 1.5 Mbps line of sight
– Joink.com http://www.joink.com/services.asp
– Service map:
http://www.joink.com/wirelesschart.asp?city=Terre+Haute
– Avoids telephone company; requires antenna
• Satellite Wireless: 1.5-11 Mbps
– Satellite downstream, telephone upstream
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Mobile Wireless
• Cellular wireless
• WLAN technologies (802.11b,
Bluetooth, 802.11, 802.11g proposed)
• WAP – Wireless Application Protocol
– Supports mobile Internet applications
– Client: mobile phone, PDA, laptop
– WAP proxy relays information from
Internet
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Future Technologies
• Passive Optical Networking (PON)
– Fiber to the home - split into different
channels
– Replaces separate traditional copper lines
coming into the neighborhood
• Ethernet to the Home: also fiber based
– Pilot by Yipes.com: TCP/IP router in home/ofc
– Creates an Ethernet network in home @ 10 or
100 Mbps up to 1 Gbps on fiber optic cable
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III. Internet Governance
• ISOC: Internet Society
– www.isoc.org Any member can vote on issues
• IETF: Internet Engineering Task Force
– www.ietf.org Internet architecture issues
• IESG: Internet Engineering Steering Group
– Responsible for technical management & stds
• IAB: Internet Architecture Board
– Strategic architecture oversight; appoints IETF, IESG
• IRTF: Internet ResearchTask Force
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Internet 2
• Next generation version: much faster!
– SONET and ATM OC-48 circuits: 2.4 Gbps
– SONET and ATM OC-12 circuits: 622 Mbps
• Most run on IPv6 rather than IPv4
• Gigapops – Gigabit Points of Presence
• Designed to allowing experimenting with
new protocols
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Internet 2 Information
• www.internet2.org
• www.vbns.org
• www.ucaid.edu/abilene
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