Download Internet and World Wide Web

E-Commerce:
Fundamentals and Applications
Chapter 2 : Internet and World Wide Web
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Outline
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An Overview of the internet
Brief history of the web
Web system architecture
Uniform resource locator
Overview of the hypertext transfer protocol
Hypertext Transfer Protocol(HTTP)
Generation of dynamic web pages
Cookies
HTTP/1.1
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Basic Network Architecture
R
R
Internet
R
modem
ADSL
ISP
Dedicated
Connection
Private
network
R
: Router
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Layered Model for the Internet
Application Layer
Transport Layer
Network Layer
Link Layer
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Processing at Each Layer
Application
Header
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Application Data
Application
Layer
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TCP
Header
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Application
Header
Application Data
TCP Layer
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IP
Header
TCP
Header
Application
Header
Application Data
IP Layer
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Link
Header
IP
Header
TCP
Header
Application
Header
Application Data
Link Layer
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Transfer of Packets
Host A
Application
data
Host B
Application
Application
TCP
TCP
IP
IP
IP
IP
Link
Link
Link
Link
Application
data
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Different Internet Access Methods
Access method
Maximum data rate
Telephone modem
24-56 Kbps
Ethernet (Local area network)
10/100/1000 Mbps
Integrated Services Digital Network Basic Rate
Interface (ISDN BRI)
56 – 128 Kbps
Cable modem
30 Mbps (theoretical)
1.5 Mbps shared (practical)
Asymmetric Digital Subscriber Line (ADSL)
1.5 Mbps - 9 Mbps (from network to users)
128 Kbps – 9 Mbps (from users to network)
Wireless local area network (IEEE 802.11)
1-56 Mbps
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Common Application Layer Protocols
Protocol
Purpose
Simple mail transfer protocol
Support email services
File transfer protocol
Support file transfer services
TELNET
Allow users to log in remote host
Hypertext transfer protocol
Support communications between a Web client and a Web
server
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Part of the DNS tree
Root
com
edu
gov
mil
net
org
hk
jp
…..
vbs
www
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URL
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Used to identify web pages
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Example:
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protocol://domain_name:port/directory/resource
http://www.vbs.com/welcome/main.html
General format:
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protocol://username:password@domain_name:port/directory/resource
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Request Methods in HTTP/1.0
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GET
HEAD
POST
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Commonly Used Status Codes in
HTTP/1.0
Status code
Status message
200
OK
201
Created
204
No content
301
Moved Permanently
302
Moved Temporarily
304
Not Modified
400
Bad Request
401
Unauthorized
403
Forbidden
404
Not Found
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Commonly Used Response Header in HTTP/1.0
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Location
Server
WWW-Authenticate
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Generating dynamic web pages
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Attach names and values at the end of the URL using a
query string:
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?name1=value1& name2=value2&….& nameN=valueN
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Example:
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http://www.vbs.com/servlet/booksearch?title=ecommerce&year=2000
GET /servlet/booksearch?title=ecommerce&year=2000 HTTP/1.0
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Cookies
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Invented by Netscape.
Save state data at client side.
Visit http://www.netscape.com/newsref/std/cookie_spec.html
Standardized in RFC2109
Server
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Set-Cookie: Name=Value
Client
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Cookie: Name=Value
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HTTP/1.1
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Persistent connection
Pipelining
Efficient use of IP addresses
Best support for:
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caching
authentication
language
encoding
More request methods
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