Transcript eCommerce Infrastructure - Carnegie Mellon University

eCommerce Technology
20-751
Lecture 2:
eCommerce Infrastructure
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Projected Internet Host Count
1,000,000,000
ADVERTISED HOST =
DOMAIN NAME IN DNS TABLE
100,000,000
1 BILLION
AUG. 2005
Historical
10,000,000
100 MILLION
JAN. 2001
93 MILLION
OCT. 2000
1,000,000
10 MILLION
JAN. 1996
Projected
100,000
1 MILLION
JUL. 1992
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
Jan-07
Jan-06
Jan-05
Jan-04
Jan-03
Jan-02
Jan-01
Jan-00
Jan-99
Jan-98
Jan-97
Jan-96
Jan-95
Jan-94
Jan-93
Jan-92
Jan-91
Jan-90
Jan-89
10,000
SOURCE: NGI
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Bandwidth Review
• Bit (b) = a unit of information, 0 or 1
– 10 bits can represent 1024 different messages
– 20 bits represent > 1 million
– 30 bits > 1 billion messages
• The bandwidth of a communication channel = number of bits per
second it transmits
• All channels have limited bandwidth
• One byte (B) = 8 bits (an octet)
• Transmitting 1 MB at 56K bps takes 143 sec.
• 1 GB = gigabyte takes 40 hours
– at 7Mbps 19 minutes; at 1 Gbps takes 8 seconds)
• Latency = delay from first bit transmitted to first received
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Bandwidth of a Truck
• Semi Tractor-Trailer 30’L x 10’H x 8’W  2500 ft3
• DVDs (Digital Videodisks)
– @5 GB each, 2000 GB (2 terabytes)/ ft3
– Semi holds 5 million GB = 5 petabytes (enough to store
every book ever published)
• Pittsburgh - San Francisco  3000 miles
– @ 50 miles/hour = 60 hours  200,000 seconds
– Bandwidth  25 GB / second  200 gigabits/sec
200 times the bandwidth of gigabit Ethernet!
• Problem: latency = 60 hours
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
BANDWIDTH
APPLICATION
TECHNOLOGY
Experimental
1 terabit
All U.S. telephone conversations simultaneously
Gigabit
Ethernet
1 gigabit
Full-motion HDTV
OC12 = 622 Mb
FDDI
OC3 = 155 Mb
Virtual Reality, Medical Imaging
T3/E3
T3 = 44.7 Mb
802.11b = 11 Mb
DSL ~ 7 Mb
Video Conferencing, Multimedia
Streaming Video + Voice
802.11 = 2 Mb
T1 = 1.544 Mb
ADSL
T1/E1
ISDN
128K
Browsing, Audio
ISDN
Copper
New Modem
56K
“Fast” modem
Fiber
E-mail, FTP
19.2
Old Modem
Telnet
4.8
Paging
Human speech = 30 bps
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Optical Fiber Capacity Growth 1983-2002
World record January 2002 Alcatel:
5 terabits in one fiber for 15 x 100 kilometers
1,400
OC-192, 128l
1,200
1 Terabit = 1,000
OC-192, 80l
Single
Fiber
Capacity
(Gigabits/sec)
800
600
OC-192, 48l
400
200
0
135Mb
565Mb
20-751 ECOMMERCE TECHNOLOGY
1.7 Gb
OC-48
SUMMER 2002
OC-192, 32l
OC-48, 96l
OC-192, 16l
OC-48, 40l
OC-192, 2l
OC-192
COPYRIGHT © 2002 MICHAEL I. SHAMOS
LINK
Population Per Internet Host Computer
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
LINK
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Structure of the Internet
NAP
Europe
Backbone 1
NAP
Backbone 4, 5, N
Japan
Regional A
Backbone 2
NAP
NAP
Backbone 3
Australia
Regional B
MAPS
UUNET MAP
SOURCE: CISCO SYSTEMS
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Internet I Network Architecture
SOURCE: LAUDON & TRAVER, p. 126
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Connecting to Internet Backbone
SOURCE: HOWSTUFFWORKS.COM
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Satellite Access
(InterSatCom)
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Circuit Switching v. Packet Switching
SOURCE
SOURCE
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
DESTINATION
CIRCUIT-SWITCHED NETWORK
20-751 ECOMMERCE TECHNOLOGY
SWITCH
DESTINATION
PACKET-SWITCHED NETWORK
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Network Topologies
• More than two computers causes complications:
1
2
3
4
LAN BUS TOPOLOGY
5
LAN = LOCAL AREA
NETWORK
• Each machine on a network must have a unique
address
• If machine 2 sends a message to machine 4, what
tells 1, 3 and 5 to ignore it, but 4 to listen?
• Ethernet protocol
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Routing
Machine 1.35 wants to send a
packet to Machine 3.249.
Machine
2.16
Routers
Routers determine the path
the packet will take.
Machine
1.35
Machine
3.249
B
A
Router A can send
the packet either way
NUMBER OF ROUTES
ROUTING STATISTICS
20-751 ECOMMERCE TECHNOLOGY
4.1
NETWORK 4 &
IT’S ROUTER
SUMMER 2002
5.9
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Routers
NORTEL
3COM
CISCO
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Packet Switching (TCP/IP)
TCP = TRANSMISSION
CONTROL
PROTOCOL
(Breaks messages into packets
and reassembles them)
IP = INTERNET
PROTOCOL
(Moves packets around
the Internet)
SOURCE: J. DECEMBER
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Packet Switching (TCP/IP)
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
IP Addresses
• Machines on the Internet need an addressing scheme (or
couldn’t receive packets!)
• Each machine has a 32-bit address assigned by the Internet
Corporation for Assigned Names and Numbers (ICANN).
• In the U.S., American Registry for Internet Numbers (ARIN)
• In Europe, Réseaux IP Européens (RIPE)
• Addresses are written in dotted decimal notation:
128 . 2 . 218 . 2
10000000 00000010 11011010 00000010
• Current max number of IP addresses = 232 ~ 4,000,000,000
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Domain Names
• IP addresses are inconvenient to remember
128.2.218.2 v. euro.ecom.cmu.edu (fully qualified)
• Domain names are alphanumeric aliases for IP
addresses. They form a tree structure of FQDNs:
ROOT
.GOV
AMAZON
.COM
MCKINSEY
.MIL
.NET
.EDU
CMU
YAHOO
.ORG
PITT
.IT
MIT
208.216.182.15 207.237.113.94
GSIA
WWW
128.2.16.175
20-751 ECOMMERCE TECHNOLOGY
YEN
CS
ECOM
EURO
128.2.218.2
SUMMER 2002
HEINZ
DOLLAR
PESO
128.2.218.4
COPYRIGHT © 2002 MICHAEL I. SHAMOS
URL: Uniform Resource Locator
• URL identifies a specific resource on a server
in a domain
• URL tells what protocol to use to access the
resource
• URL format:
http://euro.ecom.cmu.edu/program/courses/index.shtml
protocol://domain_name/path_name
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
URL: Two Hierarchies Spliced
euro.ecom.cmu.edu/program/courses/tcr751
ROOT
.GOV
AMAZON
.COM
MCKINSEY
.MIL
.NET
CMU
YAHOO
GSIA
FQDN
.EDU
YEN
CS
.ORG
PITT
ECOM
EURO
.IT
MIT
HEINZ
DOLLAR
PESO
128.2.218.2
ABOUT
AFFILIATES
HOST
DIRECTORY
PEOPLE
PROGRAM
COURSES
tcr751
tcr753
tcr770
tcr870
index.html
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Browser
• Implements HTTP (HyperText Transfer Protocol)
– Displays web pages
– Access authentication
– Caching, freshness control
•
•
•
•
•
•
•
Font mapping, e.g. Unicode
Compression, decompression
Handles multimedia, manages plug-ins
Interprets scripts
Executes Java applets
Maintains cache, history
Manipulates cookies
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS
Q&A
20-751 ECOMMERCE TECHNOLOGY
SUMMER 2002
COPYRIGHT © 2002 MICHAEL I. SHAMOS