Web Fundamentals

TABLE OF CONTENTS
1 OVERVIEW .......................................... ERROR! BOOKMARK NOT DEFINED.
2 INTERNET .......................................................................................................... 1
2.1 COMPUTER NETWORK ........................................................................................ 1
2.2 WHAT IS INTERNET? ............................................................................................. 2
2.3 HISTORY OF INTERNET ....................................................................................... 2
2.3.1 ARPANET ............................................................................................................................. 3
2.4 WORKING OF INTERNET ..................................................................................... 5
3 NETWORK TOPOLOGY .................................................................................... 6
3.1 PHYSICAL TOPOLOGY ......................................................................................... 7
3.1.1 POINT- POINT TOPOLOGY ............................................................................................... 7
3.1.2 BUS TOPOLOGY ................................................................................................................. 8
3.1.3 STAR TOPOLOGY ............................................................................................................. 10
3.1.4 RING TOPOLOGY ............................................................................................................. 11
3.1.5 MESH TOPOLOGY ............................................................................................................ 12
3.1.6 TREE TOPOLOGY ............................................................................................................. 13
3.1.7 HYBRID TOPOLOGIES .................................................................................................... 14
3.1.8 COMPARISON OF DIFFERENT PHYSICAL TOPOLOGIES (BUS, STAR AND
RING) 15
3.2 SIGNAL TOPOLOGY ..............................................................................................16
3.3 LOGICAL TOPOLOGY ..........................................................................................16
4 INTRANET ........................................................................................................ 16
4.1 LOCAL AREA NETWORK (LAN) ........................................................................19
4.2 WIDE AREA NETWORK (WAN) ..........................................................................21
5 EXTRANET ....................................................................................................... 22
6 WORLD WIDE WEB (WWW) .......................................................................... 23
6.1 HISTORY OF WWW ...............................................................................................23
6.2 WORKING OF WEB ...............................................................................................23
6.3 WEB BROWSER ......................................................................................................27
6.4 WEB SERVER ..........................................................................................................27
6.5 WEBSITE...................................................................................................................27
6.6 INTERNET SERVICE PROVIDER (ISP) .............................................................28
7 NETWORK MODELS ....................................................................................... 28
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7.1 OPEN SYSTEMS INTERCONNECTION (OSI) MODEL ...................................28
7.1.1 APPLICATION LAYER ..................................................................................................... 30
7.1.2 PRESENTATION LAYER ................................................................................................. 30
7.1.3 SESSION LAYER ............................................................................................................... 30
7.1.4 TRANSPORT LAYER ........................................................................................................ 31
7.1.5 NETWORK LAYER ........................................................................................................... 31
7.1.6 DATA LINK LAYER ......................................................................................................... 32
7.1.7 PHYSICAL LAYER ............................................................................................................ 32
7.2 TRANSMISSION CONTROL PROTOCOL/INTERNET PROTOCOL
(TCP/IP) MODEL ...............................................................................................................33
7.2.1 APPLICATION LAYER ..................................................................................................... 34
7.2.2 TRANSPORT LAYER ........................................................................................................ 34
7.2.3 NETWORK LAYER ........................................................................................................... 35
7.2.4 DATA LINK LAYER ......................................................................................................... 35
7.2.5 PHYSICAL LAYER ............................................................................................................ 35
8 BASIC TERMINOLOGIES .............................................................................. 36
8.1 HTML (HYPER TEXT MARKUP LANGUAGE) ................................................36
8.2 DOMAIN NAME .......................................................................................................36
8.3 DNS (DOMAIN NAME SERVER) ..........................................................................36
8.4 URL (UNIFORM RESOURCE LOCATOR) .........................................................36
8.5 HOME PAGE ............................................................................................................37
8.6 HTTP (HYPER TEXT TRANSFER PROTOCOL) ..............................................37
9 HTML (HYPER TEXT MARKUP LANGUAGE) ............................................ 37
9.1 HTML VERSIONS ...................................................................................................39
10 DOMAIN NAME ............................................................................................... 39
10.1 TOP LEVEL DOMAIN (TLD) .............................................................................40
10.1.1 COUNTRY CODE TLD (CCTLD) ................................................................................. 40
10.1.2 GENERIC TLD (GTLD) ................................................................................................. 40
10.2 SECOND LEVEL DOMAIN (SLD) .....................................................................41
11 URL (UNIFORM RESOURCE LOCATOR) .................................................... 41
12 FTP (FILE TRANSFER PROTOCOL) ............................................................ 42
12.1 ASCII MODE .........................................................................................................43
12.2 BINARY MODE .....................................................................................................43
13 HTTP (HYPER TEXT TRANSFER PROTOCOL) .......................................... 44
13.1 PROPERTIES OF HTTP ......................................................................................44
13.1.1 CLIENT-SERVER ARCHITECTURE ........................................................................... 44
13.1.2 CONNECTIONLESS ...................................................................................................... 45
13.1.3 STATELESS .................................................................................................................... 45
13.1.4 STANDARDISED ........................................................................................................... 45
13.2 HTTP REQUEST ...................................................................................................45
13.2.1 INITIAL LINE ................................................................................................................. 46
13.2.2 HEADER INFORMATION ............................................................................................ 46
13.2.3 BLANK LINE .................................................................................................................. 46
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13.2.4 MESSAGE BODY ........................................................................................................... 46
13.3 HTTP RESPONSE .................................................................................................47
13.3.1 INITIAL LINE ................................................................................................................. 47
13.3.2 HEADER INFORMATION ............................................................................................ 48
13.3.3 BLANK LINE .................................................................................................................. 49
13.3.4 MESSAGE BODY ........................................................................................................... 49
13.4 HTTP METHODS .................................................................................................49
13.4.1 GET METHOD ................................................................................................................ 50
13.4.2 POST METHOD .............................................................................................................. 50
13.4.3 HEAD METHOD ............................................................................................................. 51
13.5 HTTP VERSIONS .................................................................................................51
13.5.1 HTTP/1.0 .......................................................................................................................... 51
13.5.2 HTTP/1.1 .......................................................................................................................... 52
14 MULTI-TIER APPLICATIONS ....................................................................... 52
14.1 STRUCTURE .........................................................................................................53
14.1.1 CLIENT SIDE .................................................................................................................. 54
14.1.2 SERVER SIDE ................................................................................................................. 54
14.2 WEB SERVER .......................................................................................................55
14.3 APPLICATION SERVER .....................................................................................55
14.4 DATABASE SERVER ...........................................................................................56
15 REAL WORLD WEB APPLICATIONS ........................................................... 57
16 FINACLE WEB INTERFACE ......................................................................... 60
16.1 STRUCTURE .........................................................................................................60
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1 OVERVIEW
Finacle is a web based application. Since the application is installed
in a remote machine and the user will need to access it using a network
connection. The network may be internet or intranet (network inside an
organisation). So the knowledge of internet and basics of web is basic to
understand the operation of Finacle application.
This document discusses the basics of web like
• History of internet
• Basics of web
• Some basic terms related to web
• Web interface to Finacle
2 INTERNET
2.1 COMPUTER NETWORK
A computer network is an interconnected group of computers.
Internetwork is the interconnection between two or more networks.
Internet is actually an internetwork which consists of worldwide
interconnection of several academic, governmental, public and private
networks.
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2.2 WHAT IS INTERNET?
Large amount of information can be stored in a computer. A group
of computers, connected to each other is called as a network. A network
can store an even greater amount of information. Many people can share
and work with each other’s information by being on a network. If a
network like this can exchange information with other networks, based on
certain rules (known as protocols) it becomes a part of Internet. In simple
words, Internet is a network of many networks. The information available
on the Internet changes constantly. As new computers are constantly
added to the network, the amount of information is ever growing. An
individual or a company does not run the Internet. The content available
on the Internet is called World Wide Web (www).WWW is the collection of
all the information present in the internet.
The networks connected to each other would form the Internet.
Roughly 6 million hosts and over 50 million users are hooked on to the net
today.
Using Internet you can:
􀂃 Send and receive e-mail messages
􀂃 Read Newsgroups
􀂃 Visit websites
2.3 HISTORY OF INTERNET
Internet started nearly 25years ago as a project of US department of
defence. The Technical group then created was known as Defence Advance
Research Projects Administration (DARPA). Its goal was to create a way
for widely separated computers to transfer information and data
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and to make this data communications as much reliable as possible.
DARPA required to make a network that was smart enough to recover on
its own from problems such as power failure interruption in communication
lines even in nuclear attacks. DARPA called its network as DARPA net.
Eventually the government dropped the idea that its network was
only useful for defence related projects and the network became known as
ARPA net. Around this time the government also started connecting many
of the country's universities to the network. Since then, generations of
students have studied, used and improved what is today known as
Internet. ARPA net is generally considered as the first version of internet.
2.3.1 ARPANET
The ARPANET (Advanced Research Projects Agency Network)
built by DARPA of the United States Department of Defense, was the
world's first operational network. It is generally called as the predecessor
of internet. The first ARPANET link was set up on November 21, 1969. It
was established in UCLA (University Of California, Los Angeles) for the
interconnection of four Universities. The first message sent over this
network was on October 29, 1969 at 10:30 PM.
There were four nodes in the network each representing one
university. Node is actually a machine in the network. The four nodes are:-
• University of UTAH
• UCLA (University of California, Los Angeles)
• UCSB (University of California, Santa Barbara)
• SRI (Stanford Research Institute).
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In October 1972 ARPANET went 'public'. In the First International
Conference on Computers and Communication which was held in
Washington DC, the system in operation was demonstrated by ARPA
scientists by connecting computers together from 40 different locations
which inspired the Western world to research further in science. Other
networks appeared soon after this. The Washington conference also
established an Internetworking Working Group (IWG) to organize the
research taking place. Meanwhile ARPA scientists were occupied on
enhancing the system and expanding its capabilities.
• In 1972, they successfully made use of a new program which is
now referred to as e-mail, that would allow to send the
messages over the net, allowing direct person-to-person
communication.
• The new host-to-host protocols developed in the early 70s
allowed access to the hosts’ programs. Before then the system
only allowed a 'remote terminal' to access the files of each
separate host.
• A common language called TCP/IP ( Transmission Control
Protocol/Internet Protocol) was developed by ARPA scientist in
1974 with help from experts in Stanford which would allow
communication between different networks
The development of TCP/IP marked a key stage in networking
development. In 1982, ARPANET allowed TCP/IP for its functioning. This is
known as the birth of internet.
During the initial stages internet was only used for transferring files
between computers. A protocol (rule) known as FTP is used for this
purpose. FTP stands for file transfer protocol. Then a language known as
GOPHER is introduced by the University of Minnesota. It was helpful in
increasing the contents of internet. GOPHER can be used to create web
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pages in the internet. But it has some drawbacks. It does not support
multimedia content. So a new technology was introduced for writing web
pages, known as Hyper Text Markup Language. After the introduction
of HTML, internet became very powerful. HTML allows the web pages to
contain videos, sound clips, animations and so on.
So the history of internet can be divided into three stages
• Initial stage: internet is generally used for file transfer purposes
based on FTP protocol.
• Second stage: GOPHER was introduced. Web pages contained text
only.
• Third stage: HTML was introduced. Multimedia features were
introduced in web pages.
From there on, internet has grown very rapidly. Internet is now a
global network of networks. It actually consists of many networks. The
number of computers in such a network can range from two or three in a
small intranet to several thousands in large organisations.
2.4 WORKING OF INTERNET
Internet is a network of networks. Each network will contain several
computers. Each machine in the network is known as a host. It will have a
unique address known as internet address (generally known as IP
address).IP address is a 32 bit address. It will be in the form of
aaa.bbb.ccc.ddd.
One network is connected to another network using certain devices
known as routers. Information is sent from one machine to other in the
form of packets. Each packet will have a header( which contains address
of the machine to which the packets are sent) and a body. So router
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checks the header of the packet and sends the information to the specified
machine.
The following diagram shows the structure of a portion of internet
which contains four networks.
3 NETWORK TOPOLOGY
Network topology refers to the arrangement of various network
elements (nodes) in a network. There are three types of topologies.
• Physical topology
• Signal topology
• Logical topology
Router
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3.1 PHYSICAL TOPOLOGY
Physical topology refers to the physical connections and the
mapping between the network nodes – i.e., cabling or wiring system, the
layout of cables and wiring the locations of nodes and interconnections
between them. There are various types of physical topologies. The
commonly known physical topologies are:-
3.1.1 POINT- POINT TOPOLOGY
The two end points with permanent link between them would form
the simplest topology called point-to-point topology. The value of a
permanent point-to-point network is the value of guaranteed
communications between the two endpoints.
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The above diagram shows a point-point communication channel
between a printer and a computer.
The advantages of point-point topology are
• Permanent connection: -
The communication channel is permanently
associated with two points. It is also known as
dedicated connection.
• Switched Connection: -
A point-point connection can be switched-on or
switched-off according to the requirements. It is easy
to operate a point-point communication channel.
3.1.2 BUS TOPOLOGY
Bus topology is of two types – linear bus topology and
distributed bus topology.
• Linear BUS Topology: -
The nodes in this network are connected to a general
transmission medium called as ‘bus’ which has just
two endpoints which acts as the backbone or the
trunk in this topology. All information transmitted in
between nodes in the network is sent over this
common transmission medium and is accessible by
all nodes in the network.
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Linear Bus Topology
• Distributed BUS Topology: -
A topology where in the nodes are connected to a
common bus which has more than two endpoints which are
formed by adding branches to the main bus is called
distributed bus topology.
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Distributed BUS topology
3.1.3 STAR TOPOLOGY
Star topology is one in which the cables are connected to a hub and the
data flow from the nodes happens through this hub. The disadvantage in this
topology is, if the central hub or switch fails the network would also fail.
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Star topology
3.1.4 RING TOPOLOGY
A topology in which a node is connected to two other nodes, with last and the first
node connected to form a ring is called Ring topology. The data flow from one node to
another in a circular manner and is unidirectional.
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Ring topology
3.1.5 MESH TOPOLOGY
In mesh topology, every node is connected to each other such that there is
a dedicated point-point connection between every node. The number of
communication channels is very high in mesh topology. So it is costlier
compared to other topologies.
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Mesh topology.
3.1.6 TREE TOPOLOGY
A topology in which a central root node is connected to more than one node in the
form of a inverted tree structure is known as tree topology. This is also called hierarchical
topology.
A topology in which a central root node is connected to more than one node
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Tree topology
3.1.7 HYBRID TOPOLOGIES
Networks based on different physical topologies which are
connected to each other will form the hybrid topology..It can also consists
of two or more similar topologies, provided the resulting topology must not
be same as the individual topology. There are various hybrid topologies
like star-bus, star of stars, hybrid mesh etc.
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Star-bus hybrid topology
The above diagram shows a hybrid network. It is actually a starbus
network. Here two star topologies are connected as a bus topology.
3.1.8 COMPARISON OF DIFFERENT PHYSICAL TOPOLOGIES (BUS,
STAR AND RING)
Features Bus
topology
Star topology Ring
topology
Expense Low Medium High
Reliability Good Excellent Good
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Geographically coverage
ability
Poor Good Excellent
Ease of troubleshooting Poor Excellent Good
3.2 SIGNAL TOPOLOGY
Signal topology is the mapping of different nodes in a network
based on the paths by which the signals pass through. Signal topology
generally refers to the actual path that the signals (e.g., electromagnetic,
electrical, optical, etc.) take when propagating between nodes.
3.3 LOGICAL TOPOLOGY
Logical topology refers to the mapping of nodes based on the paths
taken by actual data in the network. It is similar to signal topology, but
here the determining factor is path of data, not signals. In many cases
logical topology and signal topology are used interchangeably.
4 INTRANET
Intranet is the internal network of an organisation. It is also known
as corporate portal. It contains all the web pages, email services, product
details, telephone directory etc. of an organisation. An intranet of an
organisation is accessible to employees of that particular organisation
only. A software known as firewall is used to ensure this. Firewall checks
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whether the authorised person only can access the intranet. It checks all
network traffic through the company’s intranet.
Intranet also known as corporate portal or private business network
utilizes standard network software and hardware technologies like
Ethernet, TCP/IP, WiFi, Web browsers and Web servers. Internet access
included in the organization’s intranet cannot be directly accessed from
outside as it will be firewalled. Intranets use the same HTTP server (Web
server) technology, HTML hypertext links and communications protocols as
the public Web.
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The above diagram shows a schematic representation of an intranet
of an organisation. It may contain different ingredients like management
of projects, document repositories, customer supports, e-business
activities etc.
An intranet can be called as “ a private version of an Internet” or “
a version of the Internet confined to an organisation”because Intranet
uses the same technologies and concepts used to build Intranet like clients
and servers running based on a protocol. When there is need for internet
from Organization’s Intranet, it is provided through a firewalled gateway,
along with encryption of messages, user authentication and often makes
use of virtual private networks (VPNs). Through such systems and
devices off-site employees can access company information, computing
resources and internal communications.
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4.1 LOCAL AREA NETWORK (LAN)
A computer network which covers small geographic area like office,
home or group of buildings and which is used often to achieve Intranet is
called a LAN. The major differences between a LAN and internet are: -
• The data is transfer in LAN is much faster when compared to
that of internet.
• LAN is limited to a small geographical region, but internet
can be accessed from anywhere in the world.
• A dedicated telecommunication line is required for internet
but it is not needed in LAN.
• Telecommunication line is required for internet.
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The diagram represents a small local area network (LAN) with five
nodes. A device known as concentrator or hub is used to connect the
nodes. LAN is designed based upon Ethernet.
Ethernet:-
Ethernet as the name suggests has been evolved from the ancient
term “ether”, meaning the medium through which light propagates.
Basically Ethernet defines the wiring and signalling standards used for the
network which is usual a Local Area Network (LAN). It uses the idea of a
shared coaxial cable which acts as the media through which the
transmission takes place and hence the communication between
computers. The cable used for transmission purposes can be referred to as
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the “ether” and hence the name Ethernet. This technology has been
incorporated from computer networking technologies.
Over a period of time, cost effective and highly reliable Ethernet
hubs and switches have replaced the crude but simple concept of coaxial
cables, and form the complex networking technology that underlies most
LANs.
4.2 WIDE AREA NETWORK (WAN)
Network over a large area is termed as Wide Area Network (WAN).
Usually this type of network would be spread across geographical boundaries
using routers and public communication links. Internet would be a perfect
example for a WAN. Other examples include telephone lines, microwave links
and satellite channels.
The above diagram is a schematic representation of a typical wide area
network (WAN). It is actually a network of different LANs which are located in
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fairly remote areas. These LANs are connected using certain devices known as
routers.
Usually the transmission rate across this network would be in the range
of 1200 bits/sec to 6 Mbit/sec. ATM and leased lines can even have
transmission speeds greater than 156 Mbit/sec.
5 EXTRANET
A private network which uses Internet protocols, network
connectivity and public telecommunication system to share a part of
organization’s data to its stakeholders securely is called an extranet. It can
also be termed as an extended Intranet shared over the internet to
registered users outside the company, enabled by authentication
mechanisms on a login page.
Since that extranet is over internet, security and privacy is a must.
For these reasons firewalls, digital certificates and VPN (virtual private
network) are a must.
For example some parts of sparsh like the leave system can also be
accessed from the internet, but we need to give our credentials for
authentication purpose.
Extranet has some disadvantages also. They are: -
• Very expensive with hardware, software and training costs
coming into picture.
• To secure the data over extranet would be a major concern.
• Extranet may reduce personal contact (face to face
meetings) with stakeholders, which can cause a lack of
connection between the company and its people thus
hurting the loyalty of its business partners.
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6 WORLD WIDE WEB (WWW)
World Wide Web (www), generally shortened to web, and refers to
the complete content of internet. The web contains all the web pages
which are written using a markup language like HTML which can be
accessed via internet.
6.1 HISTORY OF WWW
The whole idea of www was introduced in 1989 by Sir Tim
Berners-Lee, who is considered as the father of internet. Since then the
growth of internet was rapid. Tim Berners-Lee himself introduced the
terms like URL, http. He is currently the chairman of w3c (World Wide Web
consortium) which is the governing body of the web.
6.2 WORKING OF WEB
The working of World Wide Web is based on client-server
technology. The client here is a user program known as browserwhich
sends the request to server, which is a machine which contains all the web
pages. The server machine returns the requested information as the
response. So the web generally uses a request-response model.
The transfer of data between client (browser) and the server need
to be according to some rules known as protocols. The protocol used in
web is known as HTTP (hyper text transfer protocol). HTTP specifies
the type of communication and information that is sent between a web site
and a browser.
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The basic working of the web can be explained using the following
flowchart
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PC
Web Browser
Web Server
(Internet)
my.mydomain.com
202.68.33.47
DNS Server
(Local Network)
The
Internet
The steps involved in working of a web server are:-
1. User enters the URL in browser. (URL stands for uniform resource
locator, which is used to uniquely identify a resource in the
2. Translate DNS Name to IP
address
1. User
enters the
URL
www.google
.com
4. Returns
the ip
address
3. Can not resolve
locally? Resolve from
other network
5. Connect
to the
server
6. Connection
established
7. Send http
request
8. Send http
response
9. Browser Renders
HTML
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internet).This URL will contain the host’s address, which can be
either IP address or a particular name mapped to the IP address.
This name is known as domain name.
2. There will be a DNS server local to the client’s network. DNS
server will map the domain name to the particular IP address.
Local DNS Server will check whether that IP address is present in
the network.
3. If the IP address is not present in the local network, check will be
done against other DNS servers in the internet in order to get the
IP address corresponding to the domain name provided in the URL.
4. The IP address corresponding to the domain name will be returned
back to the browser.
(If the IP address of the server itself is entered in the URL, the
steps 2, 3, 4 can be avoided).
5. The browser will connect to the particular IP address through the
internet.
6. A connection will be established between client (browser) and the
server.
7. The browser will send a request (since we are using http, the
request is known as http request) for the web page.
8. Server will return http response and that response contains
contents of the requested page.
(The terms URL, DNS server, http request, http response will
be explained in detail later).
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6.3 WEB BROWSER
Hard disk contains this browser as software that connects the client
to internet. Browser is used to display the web pages. A web page can
contain graphics, audio and movies as well as text. Browser will be
equipped to display all these contents. Browser is generally known as
client’s window to the World Wide Web. Since documents on the web take
long time to download, browsers have a capability to store images
temporarily in a cache on the local hard disk to avoid multiple downloads
of same images.
6.4 WEB SERVER
A web server is the machine that serves the documents that the
client requests. It is capable of reading the request and processing the
request sent by the client. The web server responds to the client by
sending a web page that contains requested data as a response in HTTP
format. All the web pages will be residing in the web server.
6.5 WEBSITE
A website is a collectionof Web pages, images, videos or other
digital assets that is hosted on one or more web servers, usually
accessible via the Internet. HTML(Hyper Text Markup Language) is used to
write typical web page. This page is accessible via Hyper Text Transfer
protocol (HTTP). These web sites which can be accessed publicly
constitute “World Wide Web”. The first on-line website was created by Tim
Berners-Lee in 1991.
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6.6 INTERNET SERVICE PROVIDER (ISP)
A company or business that provides access to the Internet and
other related services is known as ISP. ISP, also called Internet access
provider or IAP. In the past, most ISPs or IAPs were run by the phone
companies. For example, the major ISPs in India are BSNL and MTNL.
Now, any group or individual with sufficient expertise and money is able
to act as ISP.
7 NETWORK MODELS
Network is the interconnection of different computers. Network
model is the representation of a network as different layers. It illustrates
the transfer of data in a network, what are the different protocols used for
data transfer etc. There are two network models.
• Open Systems Interconnection (OSI) model
• Transmission Control Protocol/Internet Protocol (TCP/IP)
model
7.1 OPEN SYSTEMS INTERCONNECTION (OSI) MODEL
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OSI model is a newer network model compared to TCP/IP model. It is also known
as the OSI seven layer model since it contains seven layers. The OSI Model
consists of the Application Layer, Presentation Layer, Session Layer, Transport
Layer, Network Layer, Data Link, and Physical layers from top to bottom. Each
layer is capable of servicing the layer above it and issues service requests to the
layer below it. A layer is a collection of related functions.
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From the diagram the data we can see that the data is transmitted
from the application layer to the physical layer and data is received from physical
layer to application layer.
7.1.1 APPLICATION LAYER
The seventh level of the OSI model is Application Layer. It interfaces
directly to the application. Sometimes presentation layer services application
layer .HTTP, FTP are examples of protocols in the application layer.
7.1.2 PRESENTATION LAYER
It is the sixth level of the OSI model. It accepts service requests from the
application layer and responds to the request .It also issues service requests to
the session layer. Different services like encryption (for security purposes),
structuring of data using XML (extended markup language) are done in this layer.
7.1.3 SESSION LAYER
It is the fifth level in this model. It responds to service requests from the
presentation layer. Transport layer which is below it receives requests from this
layer. The session layer helps in opening, closing and managing a session. The
session would be between application processes which are at end-user side, i.e. a
semi-permanent dialogue. Applications communicate in the form of requests and
responses; session layer is responsible of maintaining session for such
communications.
This layer provides synchronization. Synchronization is the process where
transmitter sends the data and at the same time receiver receives the data. It is
very important in cases like web conferences, online TV applications where video
and audio should be transmitted simultaneously.
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7.1.4 TRANSPORT LAYER
It is the fourth level of OSI model where it responds to service requests
from the application layer and will issue service requests to the network layer.
Transfer of date will be in the form of packets in this layer which will have a
header and a body. Header contains source IP and the destination IP. The body
contains the data to be transferred.
TCP is an example of a protocol in this layer. Transport layer provides
some services. They are
• Transport layer is connection oriented.
• Data reliability is present in this layer. That means the errors in
data transfer is minimised. This is done by re-transmitting the
erroneous packages.
• Network congestion can be controlled.
• The concept of ports in introduced in this layer. Ports can be used
to operate different data transfers at the same time using a single
machine.
7.1.5 NETWORK LAYER
The third layer in OSI model is network layer. It is sometimes
called as internet layer. It acts as an interface by responding to the service
requests from transport layer and issuing them to the data link layer. The
services like packet forwarding and packet routing are done in this layer.
Forwarding is the process in which a packet is passed from one node to
another whereas routing is the process in which the most appropriate path
of packet transfer is selected.
Internet protocol (IP) is a protocol in this layer.
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7.1.6 DATA LINK LAYER
The second layer in the seven-layered OSI model is data link
layer. It responds to the service requests from network layer and issues
service requests to the physical layer as well. It transmits data between
the adjacent network nodes in a wide area network and also between
nodes on the same local area network segment. The data transfer between
network entities in both functional and procedural means takes place in
this layer and also the means to detect and correct the errors that may
crop up in the Physical layer.
Following are the services provided by data layer.
• Error detection
• Flow control.
Example of data link layer protocol is Ethernet.
7.1.7 PHYSICAL LAYER
The first layer in the OSI model of computer networking is
physical layer. It carries out the services requested by data link layer. It
is the basic network layer which provides the only means to transmit raw
bits rather than sending packets over a physical data link connecting
network nodes. The torrent of raw bits are grouped into code words or
symbols and then converted into a physical signal which is then
transmitted through a physical transmission medium. The type of network
topology (which could be LAN, bus, star) is specified in this layer.
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7.2 TRANSMISSION CONTROL PROTOCOL/INTERNET
PROTOCOL (TCP/IP) MODEL
TCP/IP model was created in 1970 by DARPA (Defence Advanced
Research Projects Agency), an agency of United States Department of
Defence. Arpanet, which is the predecessor of internet is created based
on this model. TCP/IP model has five layers. They are –
TCP/IP Model has five layers, namely Physical layer, Data link layer,
Transport layer, Network layer and Application layer.
Schematic representation of TCP/IP model is shown below
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7.2.1 APPLICATION LAYER
The top layer of the TCP/IP model is Application layer. Here, the
data in the application specific format is transferred from program to
transport layer. It does the work of session layer, application layer and
presentation layer in the seven layer OSI model.
Examples of Application layer protocols are TCP, FTP (file transfer protocol)
and telnet (which uses a thin client to get connected to the server).
7.2.2 TRANSPORT LAYER
The layer next to application layer in TCP/IP model is transport
layer. It is responsible for end-to-end message transfer capabilities
autonomous to the underlying network with error control, flow control and
fragmentation. This can be of two types
i. Connection oriented
In a connection oriented type, connection between
end points should be established before transferring
any data. TCP is an example of connection
oriented protocol
ii. Connectionless
In a connectionless type data can be sent between
end points without even establishing a connection.
UDP (User Datagram Protocol) is an example of
connectionless protocol. UDP allows computers to
send datagram between each other. Datagram is
similar to a packet of information.
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There are many advantages by using a connection oriented TCP
protocol. They are: -
• data arrives in-order
• data has minimum errors (i.e. correctness)
• data duplicated is discarded
• lost/discarded packets are resent
• includes traffic congestion control
7.2.3 NETWORK LAYER
Network layer forms the third layer from top in the TCP/IP model. It does
the functionality of transferring packets between networks. Internet protocol (IP) is
an example of network layer protocol. IP performs the basic task of sending
packets of data from source to target.
7.2.4 DATA LINK LAYER
The data link layer is the second layerl. This layer has the functionality of
adding the header information to the packet and also to transfer packets to the
physical layer. The layer where packets are intercepted and sent over a
virtual private network.
7.2.5 PHYSICAL LAYER
The first layer in TCP/IP model is Physical layer. It is accountable
for encoding and spread of data through network communications media.
It sends the data in the form of bits from the Physical layer of the source
device and is received at the destination device. It also contains many
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hardware-related network design issues. For example, LAN, WAN and
wireless technology.
8 BASIC TERMINOLOGIES
8.1 HTML (HYPER TEXT MARKUP LANGUAGE)
The basic language for designing the websites is HTML. It is a
markup language. Markup language is utilized to organize and format
text. It consists of text embedded in different tags.
8.2 DOMAIN NAME
Domain name identifies a computer on the Internet belonging to
particular network. These names appear as a part of a Website's URL,
e.g.sathishtechsys.com. These types of domains are also called as hostname.
8.3 DNS (DOMAIN NAME SERVER)
Web server contains all the web pages. Each web server will have a
specific IP address. It is difficult to memorize IP addresses of the entire
servers. So we can map the IP address to a particular name. This is known
as domain name. The domain name is mapped to the IP address using
DNS(Domain Naming Systems). Generally, there will be a DNS server local
to each network in the internet.
8.4 URL (UNIFORM RESOURCE LOCATOR)
Address of the webpage is structured by URL. For example, the URL for
Sathishtechsys is www.sathishtechsys.com . The resource of web pages is uniquely
identified by URL. The clients require this URL to access the web pages.
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8.5 HOME PAGE
This forms the website’s main page. the home page will come up by typing
the URL of the website. We can navigate any other web page of that
particular web site from the home page.
8.6 HTTP (HYPER TEXT TRANSFER PROTOCOL)
HTTP defines the rules based upon which the data is transferred between
web browser and web server. For accessing the required web page, an
http request is sent to the server by the browser. After receiving the http
request, the server will send required webpage as http response.
Detailed explaination of all these terms are made in the coming sections.
9 HTML (HYPER TEXT MARKUP LANGUAGE)
HTML, its a markup language which is used for writing the
websites. Markup language is used to structure and format text. The
compostion of text-based information in a document is described using
HTML. This is done by denoting certain text as links, headings,
paragraphs, lists and so on and it also adds the text with interactive
forms, embedded images and few other objects. HTML is created in the
form of tags, surrounded by angle brackets.
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First a markup language introduced was called as SGML (standard
generalised markup language). All the other markup languages are further
developed from SGML. So SGML is called as the mother of all markup
languages.
HTML can be understood by all browsers. It is also platform
independent (means HTML can be used in any operating system like
Windows, Solaris etc.). A simple html page looks like the following.
<html>
<head>
<title>A sample HTML page...</title>
</head>
<body>
<center>
<h2>A HTML Page</h2>
<p>This is a sample HTML page which demos <b>Bold</b>,
<i>italic</i> text and a table.
</center>
</body>
</html>
The portions enclosed between “<” and “>” are known as markup tags.
They are used to structure and format the text.< body>, <head>,
<center> etc. are examples of markup tags.
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9.1 HTML VERSIONS
• The first version of HTML was introduced in July, 1993 by Tim
Berners-Lee.
• Second version HTML 2.0 was introduced in April, 1995.
• HTML 3.0 was launched in September, 1995. HTML 3.0 contained
some complex mathematical elements, more attributes for tables
etc.
• After HTML 3.0, w3c (World Wide Web consortium) launched the
next version HTML 3.2 in January, 1997. Interestingly, HTML 3.1
was not officially launched.
• Next version HTML 4.0 was introduced in April, 1998.
• Latest version of HTML is HTML 5 which was introduced on 22
January 2008.
10 DOMAIN NAME
Domain name which are nothing but the hostnames which forms a
part of the Web site's URL, e.g.sathishtechsys.com helps in identifying a computer
or computers on the Internet.
Domain names provide standard names for numeric IP addresses
which can be remembered easily. It makes Internet users to simply find
and converse with web sites and other server-based services. The domain
name system is flexible which will allow assigning multiple IP addresses to
single domain or a single IP address can be allotted multiple domain
names. Domain names are often referred to as domains.
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The domain name is divided into two parts – top level domain and
second level domain.
10.1 TOP LEVEL DOMAIN (TLD)
A top-level domain, referred to as a top-level domain name (TLDN)
sometimes. It is the part of the domain name which comes after the final
dot in it. For instance, in the domain name www.sathishtechsys.com, com or COM
is the TLDN. The top level domain names are standardized to mainly two
divisions.
10.1.1 COUNTRY CODE TLD (CCTLD)
A CCTLD is an Internet top level domain generally reserved for a
country. Creation and delegation of ccTLDs is achieved by the Internet
Assigned Numbers Authority (IANA).
Examples for ccTLD are .in, .us, .uk etc.
10.1.2 GENERIC TLD (GTLD)
A GTLD is a top-level domain used by a particular organization
class. These are to be minimum three letters long, and are named for
representing type of organization (for example, .com for commercial
organizations).
Examples for gTLD are .com, .edu, .org etc.
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10.2 SECOND LEVEL DOMAIN (SLD)
Second-level domain (SLD) is a domain that is directly under a toplevel
domain (TLD). It is the portion in the domain name that comes
before the final dot. Every organization can get their own second level
domain name provided they are registered through domain name
registrar.
For example, in the domain name www.sathishtechsys.com, sathishtechsys is the
second level domain.
11 URL (UNIFORM RESOURCE LOCATOR)
URL is the address of the web pages. For example, the URL for
Sathishtechsys is www.sathishtechsys.com . URL uniquely identifies a resource of web
pages. The clients require this URL to access the web pages.
URL generally has the following structure:
protocol://host:port/path
i. Protocol:-
It indicates a rule that is used for the data transfer (it can be
http, ftp, etc.).
ii. Host:-
It contains the IP address or the domain name of the web
server which contains the web pages.
iii. Port:-
It specifies the port number using which the http request and
http response can be passed. It is optional.
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The default port number for http is 80. This port number will be
used if no other port is mentioned in the URL.
iv. Path:-
It refers to the complete path of the document in the host.
For example,
Consider a URL http://server1.mydomain.com:8080/index.html
Here,
Protocol: - http
Host: - server1.mydomain.com
Port: - 8080
Path: - /index.html
URL is also known as URI. URI stands for Uniform Resource Identifier.
12 FTP (FILE TRANSFER PROTOCOL)
FTP is a system protocol which will be used for transferring data
from one computer to another through a network, like the data that is
transferred s over the Internet. The default port for FTP is port no: 21. The
two modes of data transfer are ASCII mode and BINARY mode.
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12.1 ASCII MODE
When a file is transferred using an ASCII mode, the individual
letters, numbers, and characters are transferred using their ASCII
character codes. In this mode which is used as default by most FTP clients,
the data will be saved in a text file in the proper format at the receiving
machine
12.2 BINARY MODE
In "Binary-Type transfer", the sending machine sends each file bit
by bit and as the recipient stores the bit stream as it receives it.
FTP has some drawbacks compared to HTTP. They are:-
• Security Issues:-
Passwords sent using FTP is in the form of
clear text. Clear text is type of text which can not be
encrypted. So passwords can seen by anyone who
can access the communication channel. This causes a
key security issue.
• Firewall:-
It is very difficult to install firewall for data
transfer using FTP. This is a major issue in case of
access authentication.
• Difficulty in programming:-
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FTP programming is difficult compared to that
of HTTP. We require a more number of commands to
initiate a file transfer.
13 HTTP (HYPER TEXT TRANSFER PROTOCOL)
HTTP refers to the rules based upon which the data is transferred
between web browser and web server. It also determines how the data is
transferred from the client to the server and vice-versa. The concept of
HTTP was introduced by Tim Berners-Lee in 1990. HTTP specifies the
functioning of a web based application.
HTTP is a request/response model between a client and a server.
The end user will be the client and the web site will be server. The client
makes http request using web browser which is called as theuser agent.
The responding server is know as origin server .It stores or creates
resources such as HTMLfiles and images.
13.1 PROPERTIES OF HTTP
13.1.1 CLIENT-SERVER ARCHITECTURE
The HTTP protocol is request/response process. A request is sent in a
particular format, once the client establishes the connection with the
server and this type of request is known as http request. The web page
contents are sent as the part of the response to the client.This is known as
http response.
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13.1.2 CONNECTIONLESS
Even though we mention that connection is established between client and
server, the protocol is known as connectionless because once the single
request has been processed, the connection is dropped as in the case of
the earlier versions of HTTP.
13.1.3 STATELESS
After the client's request receives the response from the server, the
connection between client and server is dropped and not recalled. There is
no "memory" between client connections. So the server can not store any
information which is entered by the client. Server will treat each
subsequent request as a new one.
13.1.4 STANDARDISED
HTTP is standardised. That means any vendor’s browser (like internet
explorer, Mozilla Firefox) can understand the http protocol. It is also
platform independent. So HTTP can operate with any operating system.
13.2 HTTP REQUEST
The client (browser) requests for a particular web page from the web
server. This is known as http request. HTTP request will have a specific
structure. The web page cannot be accessed if there is violation of this
syntax in the requests sent. The sending of HTTP request happens inside
the browser.
HTTP request has the following four parts: -
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13.2.1 INITIAL LINE
The initial line of HTTP request contains: -
i. The http method (the method of data transfer between browser
and server, which will be explained later).
ii. URL (actually the request will contain the path of the required
document).
iii. The protocol version (which can be like HTTP/1.0 or HTTP/1.1)
13.2.2 HEADER INFORMATION
After the initial line the http request can contain some header information.
The header information will include details like
• Client information, which tells us which browser, is used.
• Acceptable data formats, which tells us what are the data
formats that can be allowed by the browser.
13.2.3 BLANK LINE
A blankline after the header information is used to separate header
information from the message body
13.2.4 MESSAGE BODY
Message body contain information. This information will be sent out to the
server.This is used only with http POST method.
example of an http request is
GET /usr/index.html HTTP/1.0
User_Agent: Mozilla/3.0 Gold
Accept: text/plain
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Accept: text/html
Here,
Path of the document: /usr/index.html
Browser: Mozilla/3.0 Gold
Data formats accepted are plain text and html text.
13.3 HTTP RESPONSE
Server receives the request from the client and the contents of the
requested web page will be sent as a response. This is known as http
response. Http response will have a specific structure.
HTTP response has the following four parts: -
13.3.1 INITIAL LINE
Initial line is also known as status line.
The initial line of HTTP response contains: -
i. The protocol version (which can be like HTTP/1.0 or HTTP/1.1).
ii. Status code, which stand for the status of the http request and the
document.
iii. Status description, which describes the status code.
Different HTTP status codes: -
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For example, when we request for a page which is not present in the
server, the browser will show “404: page not found”.This is actually the
status code and description.
13.3.2 HEADER INFORMATION
After the initial line the http request can contain some header information.
The header information will include details like
• Enter name or numberServer information, which tells us
which type of server, is used.
• Date and time of response.
• The requested page contains the type of data, which can be
like text/plain or text/html.
• Length of the information being sent along with the
response.
Status code Description
200 OK
302 Found
400 Bad Request
401 Unauthorised
403 Forbidden
404 Not found
500 Internal Server error
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13.3.3 BLANK LINE
After the header information the http response should contain a blank line
to separate the header information from the message body.
13.3.4 MESSAGE BODY
In HTTP response, the message body has the contents of the documents in
an html page or any information that are required by the clients.
Eg:
HTTP/1.0 200 OK
Server: NCSA/2.0
Date: Wed, 05 May 2004 16:00:04 GMT
Content-type: text/html
Content-length: 2400
<html>
<head>
<title>Welcome to Sathishtechsys Home Page</title>
</head>
<body>
…
</body>
</html>
13.4 HTTP METHODS
In HTTP methods, the client information is sent from client to
server. Some of the examples for methods are GET,POST,HEAD etc.
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13.4.1 GET METHOD
In GET method, the client side information is sent to browser as
parameters. These parameters will be encoded with the URL as namevalue
pair.
For example,
http://sparsh/v1/ASPX/Search.aspx?strSearch=bangalore
The above shown URL is an example for using GET method.
The information entered by client is bangalore.’strSearch’is the parameter
used in the URL for the value ‘bangalore’
• GET method is faster compared to POST method.
• The size of data that can be sent is limited to 2MB. (This is browser
dependant).
• Generally critical information like passwords are not passed using
GET method.
GET is the default HTTP method.
13.4.2 POST METHOD
In POST method the information from client is sent to server as
part of the message body of http request. The data can also be encrypted
to ensure the security.
• POST method is slower compared to GET method.
• The pages which uses can not be book marked.
• Large sized data can be sent via POST method.
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• Critical information like passwords are passed using POST
method. They are generally encrypted.
13.4.3 HEAD METHOD
The HEAD method gets only the information about the document,
not the document itself. As a less data is transferred, HEAD is much faster
than GET.
For example, consider a situation in which we want to check whether a
document is modified after a particular time. HEAD method can be used in
such situations, which shows the last modified time.
13.5 HTTP VERSIONS
There are different versions of HTTP which are developed during the last
decade.
13.5.1 HTTP/1.0
HTTP/1.0 is the first version of HTTP. It is introduced in May 1996. Before
that some deprecated versions of HTTP were used. HTTP/1.0 is a
connectionless and stateless protocol.
• In this version, after the response to a particular request has been
given, the connection is withdrawn. That means, one network
connection can process only one request. So it is known as
connectionless protocol.
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• Also HTTP/1.0 can not store the information entered by the client in
memory. So it is known as stateless protocol.
13.5.2 HTTP/1.1
The second version of HTTP, known as HTTP/1.1 is introduced in June
1999. It can not be called connection less because it can process multiple
requests with one connection. But it is stateless as it can not store the
client information in memory. This is the version which is currently in use.
14 MULTI-TIER APPLICATIONS
Generally business applications are designed in different tiers.
Three-tier client-server architecture is generally used in web based
applications like Finacle.
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The three tiers are: -presentation tier, application tier and data tier.
i. Presentation tier: - Presentation layer which is the highest
layer in the application takes care of the display in the
browser. It can communicate with other tiers. Web servers
are the main components of presentation tier. Graphical
User Interface (GUI) is provided by the presentation
layer.
ii. Application tier: - Application tier takes care of the
business logic. That means the basic functionality of the
application is carried out by the application tier. Application
server controls the functionality of the business application.
iii. Data tier: - Data is stored in this tier. Data tier mainly
consists of Database Servers.
14.1 STRUCTURE
Multi-tier applications will generally have a “thin client - fat
server” structure. In this kind of structure, the client will have only web
browsers to view the web pages. So the client is called as a thin client.
Web server, Application server and Database server will be the server
side. So the server is known as fat server. The client-server architecture
for a multi-tier application can be represented by the following diagram.
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14.1.1 CLIENT SIDE
In the client side we will have only web browser. Client can view
and enter data in the web pages using web browser. Internet Explorer and
Mozilla Firefox are normally used. Here the client is known as a thin client.
14.1.2 SERVER SIDE
The server side in general three tier architecture consists of Web
server, Application server and Database server. So the server is
called a fat server. The Server will process request sent by the client and
sends the information back that is requested as an http response.
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14.2 WEB SERVER
Web Server is the important component of the presentation tier of the
three-tier client server architecture. It is actually a computer program
which accepts the http requests and sends the requested data as http
response. The data mainly consist of HTML pages. There are two types
data: -
a. Static: - Static content is the data that is present in the file system
in the database server
b. Dynamic: - The program that is run by the web server generates
Dynamic content. It is slower compared to static content.
Apache, Microsoft IIS are examples of web servers which are commonly
used.
14.3 APPLICATION SERVER
Application server is the major component of application tier of
three tier client-server architecture. Application server helps the thin
clients to access the database and do the necessary operations. Business
logic and data access is handled by the application server, hence known as
centralization. No programming is required for the applications instead;
they are assembled in the form of building blocks that are provided by the
application server. So application development becomes easier;
Application servers are computer programs which help the client to access
the database. They can communicate with the web server and also with
the database. They are operating system independent. Some of the
operating systems like Windows, Solaris etc are used by the application
server.
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The main advantages of using an application server are: -
i. Centralised Configuration: -
The changes to the application, mainly business logic
needs to be done at only place. So the application
maintenance is easy.
ii. Security: -
The application can be accessed only through a single
point. So all the database and application accesses can
be monitored.
iii. Performance: -
The network traffic can be controlled. So the number of
users accessing the application can be controlled and
hence performance is increased.
14.4 DATABASE SERVER
Database server is a computer program which provides database
services to other computers or computer programs. Database servers
store database on a single computer system which can be used
concurrently. According to the client-server model, an application is
divided into two sections by the database server. One is front end and the
other is back end. The front end shows requested data which runs on the
user’s computer. The back end handles tasks like data analysis and
storage which runs on the server.
Advantages of using a database server: -
i. Users can store data in one location in the center in the database
server.
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ii. Complex functions like searching, sorting, and indexing are done
on the server itself. So network traffic is reduced because some
items are to be transferred between the client and the server.
iii. The security of the database server is enhanced because of the
centrally stored data.
iv. Using its own processing power the database server searches for
the requested data, rather than sending the complete data to the
client so that the client searches for the data, as is done in a file
server.
v.Concurrent access to data is allowed using the database server
15 REAL WORLD WEB APPLICATIONS
The web applications which are accessible through the internet are
known as real world web applications. Real world web applications
generally use three-tier client-server architecture. The client is generally
known as thin client. A classic web based application is shown in the
diagram below,
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The above block diagram is divided into two sections: -
a. Client side: -
In a common web based application, the client will be
connected to a local network, which can be the client’s
organisation intranet. As we know, each organisation’s
intranet will have a firewall, to check whether the
authorised personnel only can access the local
network.Therefore, the client can connect to the internet
from his intranet through the firewall. As we know client
sends the http request from the browser.
Network
Network
Web Server
Client
The Internet
Client Firewall
Client
Web Server
Web Server
Databas
Databas
To Other
Applications or
Application Servers
App
Server
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T101 – WEB FUNDAMENTALS Page 59
b. Server Side: -
The server side also have a firewall to monitor the
server access. The web server processes the http requests
that comes from the client. Web server is responsible for
displaying the web pages. Web server handles the
presentation part of the application. The web servers
generally used are apache and Microsoft IIS. As the web
server communicates with the application server webserver
acts like an intermediary between client and the application.
Application server gets the requests from the web
server. The business logic and the database access is
handled by the application server. Business logic is the
fundamental functionality of the application. Client can not
directly access the database. Client can access the appliace
The data is present in a machine known as database
server. This can only be accessed by the application server.
The following is the flow of working of a real time web based application: -
i. Client sends the http request from the browser
through the firewall in his intranet.
ii. The client is authorised by the server whether it can
access it or not using firewall.
iii. Web server receives the request and web page is
shown in the browser.
iv. The client accesses the application and database
through the application server. The communication of
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T101 – WEB FUNDAMENTALS Page 60
Client with the application server is through the web
server.
16 FINACLE WEB INTERFACE
Finacle is a web based application. It can be accessed via intranet as
well as internet. The key features of Finacle web interface are: -
• Provides a browser-based GUI interface to Finacle
The Finacle application can be accessed through any
browser. User will see an interface which is to be worked on.
• Allows integration with other browser-based applications
With the help of single sign on (SSO), we can log on to
other applications by logging into only one application.
• Designed to work over intranet as well as internet
We can access the Finacle application both from internet and
intranet.
• Allows fast data-entry through use of function keys rather than the
mouse
The data entry and navigation in Finacle application happens
through function keys. So it is easier for the user to operate.
16.1 STRUCTURE
The structure of Finacle web interface can be explained by the
following diagram.
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T101 – WEB FUNDAMENTALS Page 61
Client Side: -
The client side of Finacle web interface consists of a web browser
through which the client can see the web pages and do the required
operations. The web browser generally used is Internet Explorer 6.0. But
any other browser can also be used.
Server side: -
The server side of Finacle web interface can be divided into
two portions: -
i. Components of web server
Web Server accepts the http requests and sends the
requested data as http response. Web server is responsible for
the presentation part of Finacle application. It helps in loading
Client Web Server Application Server
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the web pages. It has mainly two components – Appletcomp
and Webcomp.
a. APPLETCOMP: -
Appletcomp stands for applet component. It
contains the Finacle applet. The Finacle applet is
responsible for presenting data received from the
server in a graphical user interface. This applet
consists of a set of JAVA class files bundled together
in a jar (java archive) file. Finacle applet is re-usable,
that means the same applet can be used in different
servers.
Appletcomp is responsible for the appearance
of the web page. Actually there is only one applet. It
gets re-painted for every web page. So the layout of
every web page is similar.
b. WEBCOMP: -
Webcomp stands for web component. It is the
place where all the web pages reside. Appletcomp and
Webcomp are the components of web server. Upon the
client sends the request from the browser the
requested page is picked up from the Webcomp and it
is displayed on the browser. If client wants to do some
operation it can communicate with the application
server through the web comp. Appletcomp and
Webcomp can be used with any platform like windows
or SunOS.
ii. Components of application server
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T101 – WEB FUNDAMENTALS Page 63
Application server helps the clients to access
the database and do the necessary operations. It
does the business logic for the client. B2KCOMP is
the main component of Finacle application server.
B2KCOMP: -
Clients can access the application and the
database through b2kcomp. It is responsible for the
login service. B2kcomp allows the users to login to
the application. It also takes care of the session
management. B2kcomp is installed in the same
server where the Finacle application is present. So it
is specific to the platform in which the application
server is operating.