CHAPTER 2

E-commerce
Infrastructure

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 Discussion Points
Take one business model from the traditional business
firms ( eg. Restaurant, Wholesaler , …) what are the
components of their business infrastructure?
What are the key e-commerce enabling technologies?
What is Internet? What are the key concepts +What
are its components
List out available services in the Internet
What we mean WWW or Web? What are its essential
components?
How the Internet works?

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 The enabling technologies
The Internet and the World Wide Web
Internet: an interconnected network of thousands of
networks and millions of computers linking
businesses, educational institutions, government
agencies, and individuals together
WWW: One of the Internet’s most popular services,
providing access to billions of web pages

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 The Internet Evolution
History of the Internet can be segmented in to three phases
Innovation Phase (1961 – 1974)
 Fundamental building blocks were conceptualized and realized
 Packet-switching, client/server computing and TCP/IP
 Purpose: to link together large mainframe computers in college campuses and
form one-to-one communication
Institutional Phase (1975 -1995)
 Large institutions such as the DoD and NSF provide funding for the invention
 DoD develop the concept of Internet in to military communication system
called ARPANET – Advanced Research Project Agency Network, which was
a WAN to share computing facilities
 NSF began development of civilian Internet and formed NSFNet in 1986
 It was not allowed to use the infrastructure for commercial use

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 Commercialization Phase (1995 )
Private corporations involved in expanding the Internet
to be used by ordinary citizens.
The ban on the commercial use of the Internet was lifted
and leads to the explosive growth of additional services
such as e-commerce

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 Three Key Technology Concepts
Packet Switching,
TCP/IP Protocol and
Client/Server computing

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 Packet switching:
Packet switching: A method of slicing digital messages into
packets, sending the packets along different communication
paths as they become available, and then reassembling the
packets once they arrive at their destination
 Packet switching does not require a dedicated circuit.

The parcels into which digital messages are sliced for

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 Packet

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 Routers
Special-purpose computers that interconnect the
computer networks that make up the Internet
Route packets to their ultimate destination as they
travel on the Internet, the route decided by the routing
algorithms
Routing algorithm: Computer program that ensures
packets take the best available path toward their
destination

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 Routers

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 Network Protocol
There was no universally agreed upon method for
breaking up digital messages in to packets, routing
them to proper address and then reassembling them to
a coherent message
Leads to development of a standard protocol
Protocol: A set of rules for formatting, ordering,
compressing, and error checking messages

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 Layered model of Protocol
Protocols are designed according to a layered model.
 The protocol software on each computer is divided in
to modules - each corresponding with a layer
Each module only communicates with the modules
corresponding to the layer above and the layer below
All the protocol modules on a computer are
collectively called a stack or suite.
Network communication requires that the same stack
is installed on all computers

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"Layer N software on the destination computer must receive the
exact message sent by the layer N software on the sending
computer"

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 The TCP/IP Protocol
Short for Transmission Control Protocol/Internet
Protocol, is a suite of communications protocols used
to connect hosts on the Internet
A protocol stack used by the Internet, which answer
to the problem of packet management - how to deal
with packets

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 The TCP/IP Protocol
TCP/IP uses several protocols, the two main ones
being TCP and IP.

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 The TCP Protocol
TCP (Transmission Control Protocol): Protocol that
establishes the connections among sending and
receiving Web computers,
Handles the assembly and reassembly of packets
Verifying the correct delivery of data between
machines, manage retransmission

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 The IP Protocol
IP (Internet Protocol): Protocol that provides the
Internet’s addressing scheme
It is the packet switching protocol, responsible for
moving packets of data from machine to machine -
based on a four byte destination address - IP address
Hosts will have an IP address so that they can be
addressable on the Internet.
It is 32-bit numbers such as 201.61.186.227

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 Host & Domain Names
Domain name: IP address expressed in natural
language
It allows expressions such as google.com to stand for
numeric IP address (72.14.207.99)
Domain name system (DNS): System for expressing
numeric IP addresses in natural language
There are hierarchy of domain, Top level, Second
level, Third level - subnets
Eg: aaucc.aau.edu.et

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 Network interface layer
Serves as an interface to actual network hardware
Responsible for placing packets on and receiving them
from the network medium
TCP/IP does not specify any protocol here, but can use
almost any network interface available, which
illustrates the flexibility of the IP layer
Also referred to as Link layer (Data-Link Layer)

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 Application layer:
Provides a wide variety of application with the ability
to access the services of the lower layer.
This is where email, web browsers, telnet clients, and
other Internet applications get their connections.
It consists of application oriented protocols like
SMTP, SNMP, FTP, TFTP, HTTP,...
The interface between the application and transport
layers is defined by port numbers and sockets.

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Routing Internet Messages
TCP/IP and Packet Switching

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 Client/Server Computing
Client/server: A model of computing in which very
powerful personal computers (clients) are connected
together in a network with one or more servers.
Client: A very powerful personal computer that is part
of a network
Server: Networked computer dedicated to common
functions that the client machines on the network need,
such as storing files, software applications, utility
programs such as Web connections, and printers.

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 Client/Server Computing
The client/server model is a form of distributed
computing where one program (the client)
communicates with another program (the server) for
the purpose of exchanging information.
Responsibilities of server program
The server's functions include:
Listen for a client's query.
Process that query.
Return the results back to the client.

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 Responsibilities of Clients
The client's responsibility is usually to:
Handle the user interface.
Translate the user's request into the desired protocol.
Send the request to the server.
Wait for the server's response.
Translate the response into "human-readable" results.
Present the results to the user.

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The Client/Server Computing Model

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 How to get connected
The number of computer connected to the Internet
have been increasing
Projection for 2016: 3.419 billion, (from Pow
Research Center 2016 report) - Will it be overloaded?
Client / server computing is extensible:
By adding servers and clients the population of the
Internet can increase indefinitely

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 Internet I Network Architecture
The Internet Backbone: High bandwidth fiber optic
cable that transports data across the Internet
Formed by Network Service Providers (NSPs)
Fiber optic cables can have bandwidth ranging from
155Mbps to 2.5Gbps.
Usually backbones are built in redundancy so that if
one part breaks down, data can be rerouted to another
part

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 NAP / MAE and LANs
Network Access Point (NAP): one of the hubs where
the backbone intersects with regional and local
networks, and where the backbone owners connect
with one another
Metropolitan Area Exchanges (MAEs): another
name for one of the hubs where the backbone
intersects with regional and local networks
Campus networks: LANs operating with a single
organization

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 Internet Service Providers (ISP)
Firms that provide the lowest level of service in a
multi-tiered Internet architecture
Provides two modes of connection
Narrowband: the traditional telephone modem
connections operating at 56.6Kbps
Broadband: refers to any communication technology
that permits clients to play streaming audio and video
files at acceptable speeds

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 Limitation of Internet I Infrastructure
Insufficient Bandwidth
Limit audio video traffic
Latency
Message delay in live communication
Lack of Broadcasting
Congestion of internet services
Language Limitation
Unable to support reach documents

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 The Internet2 Project
Internet2®: is a consortium of more than 180
universities, government agencies, and private
businesses that are collaborating to find ways to make
the Internet more efficient.
Primary goals: Create a leading edge network
capability for the national research community
Enable revolutionary Internet applications involving
easy transfer of multimedia data
Ensure the rapid transfer of new network services
and applications to the broader Internet community

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 Focus
Advanced Network Infrastructure
High performance backbone and GigaPops
New Networking Capabilities
IPv6, QoS, Multicasting, …
New middleware capabilities
For common services and to help in
development
Advanced Applications
Require significant AV data exchange

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 Wireless web and 3G Technologies
The primary cellular telephone technology
standards:
Global System for Mobile Communications
(GSM): which is widely used in Europe
Code Division Multiple Access (CDMA) in US
Designed for voice communication than data
GPRS must be integrated

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 GPRS Technologies
General Packet Radio Switching: carry data packets,
over radio frequencies
Wireless Application Protocol (WAP) a new protocol
that enable PDA and cell phones access the web
Information sent via WAP must be written in Wireless
Markup Language (WML).
3G and W-CDMA: new generation standards to give
faster data rate
2.4 and 2.0Mbps

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 The WWW
The idea of organizing knowledge as a set of
interconnected pages was witnessed earlier
1945, Vannevar Bush and 1960, Ted Nelson
1989 – 1991 Berners-Lee and his associates at CERN
(European Particle Physics Laboratory) built on these
ideas and developed the initial versions of the four
essential components of the web - HTML, HTTP,
web server and a browser

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 Web pages
Berners-Lee created pages with links and came up
with idea of storing his pages on the Internet,
Written with HTML and clients can access the pages
using HTTP
1993: Mosaic: first web browser with GUI made it
possible to view documents on the web graphically
and could run everywhere

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 Web browsers
Browsers read HTML text on a web page and
displayed its graphical interface document
Also made universal computing possible
The sharing of files, information, graphics, sound,
video, and other objects across all computer platforms
in the world, regardless of operating system
Browsers could be made for any platform

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 How Web browsers access pages
Makes HTTP Request
Uniform resource locator (URL): The address used by
a Web browser to identify the location of content on
the Web. URL is used to request web pages from
Internet host machines:
Format: protocol://www.Domain_name.ext

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 Web servers
Behind the Client / Server computing nature of the
Internet, the most important component from the
server side is the Web Server
Web server: software that enables a computer to
deliver Web pages written in HTML to client
machines on a network that request this service by
sending an HTTP request
Leading brands: IIS and Apache

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 Web servers
In addition to locating web pages and responding to http
requests, most Web servers give other services:
Security service: authentication, SSL,
FTP: unless restricted by the setting, web servers
allow downloading and uploading of files by ftp
Search engine: enable indexing of the site’s web
pages and content, and permit easy keyword
searching of the site’s content
Data Capture: capture data for different purposes
Who has visited, how long, the date and time, which
specific pages on the server etc

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 Web servers - services
The term web server can also be used to refer to
computers running web servers
For a computer to be a web server: must have one of the
web server software installed and be connected to the
Internet, and have IP address

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 Specialized Servers
Database Server: server designed to access specific
information with a database
Ad server: server designed to deliver targeted banner
ads
Mail server: server that provides mail messages
Video server: server that serves video clips
All in one or more server hardware

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 HTML
Hypertext Markup Language: is a GML that is
easier to learn and use
HTML provides web page designers with a fixed set of
markup “tags” that are used to format a web page.
When these tags are inserted into a web page, they are
read by the browser and interpreted into a page display
Use of DTD – Document Type Definition
HTML is used to define the structure and style of a
document

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 HTML
The two competing browsers, Netscape and IE have
continuously added features to HTML
Many of which work only in one of the browsers
Threatens the attainment of universal computing
As the designers have to make sure that the pages can
be viewed by major browsers, even outdated versions
of browsers

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 XML
Extensible Markup Language: a new markup
language specification developed by the W3C
Designed to describe data and information not for
data presentation (unlike HTML)
XML can be used to represent database records and
transmit them as plain form of text
XML is extensible: the tags used to describe and
display data are defined by the user

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 XML
XML can also transform information into new format,
such as, importing from a database and displaying it
as a table.
Information can be analyzed and displayed
selectively
Enable companies to describe all of their invoices,
accounts payable, payroll records, and financial
information using a web compatible markup language

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 XML - advantages
Standardized - Many products from many vendors
are available that implement something close to the
World Wide Web Consortium Recommendation on
XML.
Simple - the technology is easy to learn and
implement, with many tutorials and "how to" books
available.
Self-describing - straightforward data exchange
applications can be written without reference to
detailed format descriptions or schemas.

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