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ELECTRONIC
COMMERCE
Internet Client-Server Application
• WWW (World Wide Web) : Protocol use HTTP
(Hyper Text Transport Protocol)
• Purpose: Offers to access to hypertext document
executable programs, and other internet resources.
• E-mail:- Protocol use SMTP (Simple Mail Transfer
Protocol), POP3 (Post Office Protocol version3),
MIME (Multipurpose Internet Mail Extension).
• Purpose: Allows the transmission of text messages and
binary attachments across the internet.
• FTP (File Transfer Protocol) : Enables file to upload
and download files across the internet.
• IRC (Internet Relay Chat):- This is service in
which participants around the world can talk to
each other in real time on hundreds of channels.
These channels based on particular topics.
• ICQ (I Seek You) : It is simply a smart way of
getting in touch with people. People who could be
communicating by email, chat, sms, phones and
makes it as straightforward as calling across room
and starting a friendly conversation.
•
The most popular method of communication
on ICQ is instant messaging, enabling you to send
a message that immediately pops up on an online
contact screen.
• MIME (Multipurpose Internet Mail
Extension) :•
Using HTTP you can transfer full motion
video sequence, stereo sound tracks and high
resolution images. MIME is extremely useful
not only to HTTP but also to other protocols.
MIME was originally developed to allow
email messages to have multiple parts with
different types of data in each part.
Network and Internet
• A computer network consist of two or more
computer that are connected to each other using
cable and other network devices that handle the
flow of data.
• Communication Switching
•
Through the use of communication switching,
computer networks allow computers to transfer
data using shared line of communications such as
cables. Communication switching works similar to
telephone switching networks. If you need to call
100 different people, you need to connect 100 lines
to your phone.
• Network used two common methods of
communication switching to transfer data.
• Circuit Switching : The switches create a
single and unbroken path between devices that
want to communicate.
•
The connection provide for transmission at
a constant data rate.
• Packet Switching :
The most computer
networks including the internet they use packet
switching technique .
• Data is transmitted in short packets. A typical
upper limit on packet length is 1KB. If a
source has a longer message to sent, the
message is broken into a series of packets.
Each packet contain a portion of user data plus
some control information.
•
At each node on the route, the packet is
received , stored briefly, passed onto the next
node. In a packet switched network data can
flow along multiple paths.
Network Routers
•
Network designers user routers to transfer data
between networks that use different network
technologies.
•
The router will transfer the packet to the other
network. To manage network traffic, network
designers also use routers to segment large sections
of a Local Area Network (LAN) to smaller segments
called subnets.
•
Routers commonly use routing tables which are
similar to look up database. Using routing tables,
routers can lookup the correct path from the packets
current location to any destination on the network.
• Routing tables has two types Static and
Dynamic.
• In Static Routing tables, the network
administrator must manually update the tables.
Network software automatically update the
dynamic routing tables. When network has
lot of traffic, the network software can update
the routing tables.
Connectionless Vs Connection
oriented protocol
• --With Connectionless protocol, Client connect to
the server, make a request , get response and then
disconnects. HTTP is connectionless protocol.
Since the connection is not maintained, no system
resource is used after transaction is completed.
• --With Connection oriented protocol, Client
connect to the server, make a request, get the
response, and then maintain the connection to
service future request. FTP is a Connection
Oriented Protocol. When you connect to FTP
Server, the connection remains open after you
download a file.
Internet Naming Convention
• -- Computers on the internet identify each other by
their IP address such as 209.194.84.59, But
remembering numbers is difficult so we assign
Names like yahoo.com etc.
• Universal Resource Locators(URLs)
• -- The URLs provide a uniform way of identifying
resources that are available using internet protocols.
• -- Protocol name is generally followed by a colon
and two forward slashes. The colon is a separator.
The double slashes indicate that the protocol uses the
format defined by CISS(Common Internet Scheme
Syntax).
• Protocol://hostname:port/path_to_resource)
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-- Some Domains URLs are
com : Commercial sites
edu : Educational sites
gov : Nonmilitary government sites
mil : Military sites
net : Network sites(developers, ISP Providers)
org : Organizational sites
Defining URLs
• -- URLs consists of characters defining by the ASCII character set,
You can use letters a-z, the numerals 0-9, and a few special
characters.
• Special Characters Used In URLs
• Characters
Symbol
• Asterisk
*
• Dollar Sign
$
• Exclamation Point
!
• Hyphen
• Parentheses (left and right)
()
• Period
.
• Plus sign
+
• Single quotation mark
‘‘
• Undersign
_
-- Other characters used in URLs have specific
meanings, as in the following
• Colon (:) - The colon is a separator. It separates the protocol from
the rest of the URL scheme.
• Eg.: http://www.yahoo.com/signin.html
• Double slash (//) - They indicate that the protolol use the format
defined by the CISS.
• Single slash (/) – The slash is also used to denote the directory
path to resource name in URL.
• Tilde (~) – To indicate that the resource is in the specified user
public html directory.
• http://www.yahoo.com/~ram
Percentage (%) – This identify escape code
• Book%20table%20of%20
At (@) Symbol – This is used to mail account to identify the site to
which mailer belongs.
• Question (?) Mark – This is used in the URL path to
specify the belonging of a query stering.
• Plus (+) sign – This is used in query string a place-holder
between words.
• Eg. Userid?word1+word2+word3
• Equal (=) sign – This is used in query string to separate the
key assigned by the publisher from the value entered by the
user.
• Eg. Userid?username=ram
• Ampersand (&) sign – This is used in the query string to
separate set of key and value.
• Eg. Id?name=ram&question
TCP(Transmission Control Protocol)
• TCP makes it possible for two computers to
communicate across the internet in a similar to the
humans use the telephone.
• Once establish the connection, they can exchange data
and then terminate the connection.
• TCP provide a connection oriented, reliable, byte stream
service.
• TCP send a segment it maintain the timer, waiting for the
other end acknowledge the reception of the segment. If
acknowledgement is not received in time, the segment is
retransmitted.
• TCP receives data from the other end of the connection.
It sends the acknowledgement.
Search Engines
• If I want to search for a particular topic. it
becomes almost impossible to find it. we may
use two basic approaches. The first one is by
search engine for specific information and the
second, by a subject guide such as Yahoo.
subject guides are browsing general topic.
• Keyword Search
• This is the most common form of text search on this web.
this means that the search engine pull out the pages
containing the words it find the matching query.
•
Concept-based Search
• The concept-based search system try to determine what
you mean, not just what you say. The concept-based search
returns the documents that are about subject/theme you are
exploring.
• Eg. If you search the word “heart”, when used in the
medical/health context, is likely to appear with such words
as lung, cholesterol, pump, blood….
•
If the word heart appears in document, the search
engine returns links for the pages on the subject of Heart,
valentine, flowers.
•
Refining Search
• --Most of the sites two different types of
searches basic and advanced
• --In basic search you just entered the keyword
without sifting through any pull-down menus
of additional options
• --In advance search searching option differ
from one search engine to another but the
ability to search on more than one word.
Software Agent
• Collaborative Agents: - Collaboration is
required when multiple agents achieve
complex goals that are difficult or impossible
to attain for an individual agent. This
collaboration takes place under conditions of
incomplete information, uncertainty, and
bounded rationality.
• Interface agents: - Interface agents learning in
the order to perform tasks for their owners.
• -- Interface agent learn typically to assist its
user better in different ways by observing,
receiving positive or negative feedback from
the user, receiving instruction from the user,
asking other agents for advice
• Mobile Agents:- Mobile agent are
computational software process capable of
roaming WAN eg. interacting with foreign
hosts.
• -- Reduced communication cost
• -- Easier co-ordination
• -- Natural Development Environment
Information agents
• -- Information agents perform the role of
managing
manipulating
or
collecting
information from many distributed sources.
They are defined by what they do.
• -- They are simply earning need or demand for
tools to manage such information explosion.
• -- There are vast financial benefits to gain.
Internet Explorer clients generally offers
browsing capabilities.
Reactive Software agent
• -- They respond in a stimulus response manner
to the present state of the environment in
which they are embedded
• -- The fact that the agents are relatively simple
and they interact with the other agents in basic
ways.
• -- Earning needs for a clear methodology to
facilitate the development of reactive software
agent application.
Hybrid Agent
• -- A hybrid approach which brings together
the strength of both the agents.
• -- Hybrid agents refer to those whose
constitution is a combination of two or more
agents.
Heterogeneous Agents
• -- A heterogeneous agent system may also
contain one or more hybrid agent.
• -- A key requirement for interoperation
amongst heterogeneous agents is having an
agent communication language through which
the different software agent can communicate
with each other.
Smart agents
• -- Smart Agents are those agents which can
learn, cooperate, and autonomous. The way all
agent are smart, but for our understanding,
when these three qualities are combined in an
agent, we call it SMART.
Internet Service Provider
• -- Companies that accessed the internet through the
existing non-profit middle level network were offered a
lower level membership than the academic member.
• -- Commercial use of internet become more common,
ISPs come into existence to provide paid access to the
various internet applications and resources for both
companies
and
individuals.
Established
telecommunications cable and commercial online
companies began to offer the service.
• -- When a user request on the internet from a
computer. the request send an ISP network,
move over one or more of the backbones and
across another ISP network to the computer
containing the information of interest. The
response to the request follows a similar path.
ISPs in India
• -- Internet access in the sense came into India in the
early 1990s. ERNet and NICNet are the
government projects.
• -- ERnet (Educational and Research Network)
project was design to provide Internet connectivity
to the premier educational and research institutions
of India.
• -- NICNet was assigned the provision of Internet
services primarily to government department and
organization.
• -- Another service provider of internet service that
proceded VSNL(Videsh Sanchaar Nigam Limited)
is a Software Technology Parks of India(STPI)
internet service. This service was permitted only
restricted audience, essentially the software
experts who fall under the STP scheme of the
DoE.
• -- On August 15, 1995, VSNL launch the gateway
internet service for providing public internet
access. Starting with dialup and PPP access in 4
meters. VSNL follows with leased line access to
subscriber followed by the setting of point
presence of P2P in Banglore and Pune.
• -- There will be different licence for different
areas. For this purpose, the entire country has
been divided into three categories.
• A) The whole of India.
• B) 20 Telecom Cities Circles in cities like Delhi,
Mumbai, Calcutta, Chennai, Ahmadabad,
Banglore, Hydrabad, Pune.
• C) Covers the secondary switching area of DOT.
• Broadband Technologies
• Broadband refers to the transmission medium
or the physical connection with witch users
can access the Internet at speeds faster.
Broadband access can be through any medium
copper, fiber, or wireless.
Digital Subscriber Line
• The limitation of their cable infrastructure, the
telecommunication industry needed a technology
that could deliver high-bandwidth Internet access
over existing phone.
• ISDN(Integrated Service Digital Network) was
offered in the mid 1990s with moderate access.
• The human ear can detect sonic waves up to
frequency of 20KHz. DSL essentially modulates
binary data into sonic frequencies above 20 KHz.
Cable Modems
• Faced with competition as well as increasing
number of customers who are switching to
digital satellite service.
• Cable Multiple service operators need to
quickly adapt value added service to capture
and retain their customer base. One of these
service is high speed internet access via cable
modem.
• Passive Optical Networks
• PON Consist of fibre optic cables and Optical
Network Unit(ONU) equipment. Optical Line
Transmission(OLT) Typically supports 32
ONU.
• Wireless LAN and LMDS
• Local Multipoint Distribution Service(LMDS)
used radio frequencies for vast development of
Internet.