Rkp internet part i

BASICS CONCEPTS OF
COMPUTER NETWORKS
Introduction to Computer Networks

Computer Networks
Computer network
connects two or
more autonomous
computers.
The computers can
be geographically
located anywhere.

LAN, MAN,WAN,PAN & CAN
Network in small geographical Area (Room,
Building or a Campus) is called LAN (Local
Area Network)
Network in a City is call MAN (Metropolitan
Area Network)
Network spread geographically (Country or
across Globe) is called WAN (Wide Area
Network)
Campus Area Network (CAN)
Personal Area Network (PAN)

NETWORK
PAN LAN WAN MAN CAN

PAN & CAN
 PAN : A personal area network is a
computer network organized around an
individual person. It generally consists of a
mobile computer, a cell phone or personal
digital assistant. PAN enables the
communication among these devices.
 CAN : The campus area network is made
up of an interconnection of LAN with limited
geographical area. Network equipments
such as switches, routers and the
transmission media i.e. optical fibre etc are
almost entirely owned by the campus
owner.

WAN
MAN
CAN
PAN
LAN

PARAMETERS LAN WAN MAN
Ownership of
network
Private Private or public Private or public
Geographical area
covered
Small Very large Moderate
Design and
maintenance
Easy Not easy Not easy
Communication
medium
Coaxial cable
– CAT 5/6,
PSTN or satellite
links
Coaxial cables,
PSTN, optical
fibre, cables,
wireless
Bandwidth Low High moderate
Data
rates(speed)
High Low moderate
DISTINGUISH BETWEEN LAN, WAN,MAN

Applications of Networks
Resource Sharing
Hardware (computing resources, disks,
printers)
Software (application software)
Information Sharing
Easy accessibility from anywhere (files,
databases)
Search Capability (WWW)
Communication
Email
Message broadcast
Remote computing
Distributed processing (GRID Computing)

Network Topology
( way of connecting computers)
The network
topology defines
the way in which
computers,
printers, and other
devices are
connected. A
network topology
describes the
layout of the wire
and devices as well
as the paths used
by data
transmissions.

Bus Topology
Commonly referred
to as a linear bus,
all the devices on a
bus topology are
connected by one
single cable.

Star & Tree Topology
The star topology is the
most commonly used
architecture in Ethernet
LANs.
When installed, the star
topology resembles spokes
in a bicycle wheel.
Larger networks use the
extended star topology also
called tree topology. When
used with network devices
that filter frames or packets,
like bridges, switches, and
routers, this topology
significantly reduces the
traffic on the wires by
sending packets only to the
wires of the destination
host.

Ring Topology
A frame travels around the
ring, stopping at each node. If
a node wants to transmit data,
it adds the data as well as the
destination address to the
frame.
The frame then continues
around the ring until it finds
the destination node, which
takes the data out of the
frame.
Single ring – All the devices on
the network share a single
cable
Dual ring – The dual ring
topology allows data to be sent
in both directions.

Mesh Topology
The mesh topology
connects all devices
(nodes) to each
other for redundancy
and fault tolerance.
It is used in WANs to
interconnect LANs
and for mission
critical networks like
those used by banks
and financial
institutions.
Implementing the
mesh topology is
expensive and
difficult.

Network Components
Physical Media
Interconnecting Devices
Computers
Networking Software
Applications

Networking Media
Networking media
can be defined
simply as the
means by which
signals (data) are
sent from one
computer to
another (either by
cable or wireless
means).

Networking Devices
HUB
Switches
Routers
Wireless Access
Points
Modems etc.

NETWORK CLASSIFICATION
BY THEIR COMPONENT ROLE
LOCAL AREA NETWORK
PEER TO PEER NETWORK CLIENT SERVER
NETWORK

PEER TO PEER NETWORK
 In peer to peer network each computer is responsible
for making its own resources available to other
computers on the network.
 Each computer is responsible for setting up and
maintaining its own security for these resources.
 Also each computer is responsible for accessing the
required network resources from peer to peer
relationships.
 Peer to peer network is useful for a small network
containing less than 10 computers on a single LAN .
 In peer to peer network each computer can function
as both client and server.
 Peer to peer networks do not have a central control
system. There are no servers in peer networks.
 Peer networks are amplified into home group.
Introduction to Computer NetworksIntroduction to Computer Networks

ADVANTAGES & DISADVANTAGES OF
PEER TO PEER NETWORK
Advantages:
 Use less expensive
computer hardware
 Easy to administer
 No NOS (Network Operating
System)required
 More built in
redundancy
 Easy setup & low cost
Disadvantages:
 Not very secure
 No central point of
storage or file
archiving
 Additional load on
computer because of
resource sharing
 Hard to maintain
version control

Client and Server
In a client/server
network
arrangement,
network services are
located in a
dedicated computer
whose only function
is to respond to the
requests of clients.
The server contains
the file, print,
application, security,
and other services in
a central computer
that is continuously
available to respond
to client requests.

CLIENT/SERVER NETWORK
 In client-server network relationships, certain
computers act as server and other act as clients. A
server is simply a computer, that available the
network resources and provides service to other
computers when they request it. A client is the
computer running a program that requests the
service from a server.
 Local area network(LAN) is based on client server
network relationship.
 A client-server network is one on which all available
network resources such as files, directories,
applications and shared devices, are centrally
managed and hosted and then are accessed by client.
 Client serve network are defined by the presence of
servers on a network that provide security and
administration of the network.

ADVANTAGES AND
DISADVANTAGES OF CLIENT-
SERVER NETWORK
Advantages:
 Very secure
 Better performance
 Centralized backup
 very reliable
Disadvantages:
 requires professional
administration
 More hardware-
intensive
 More software
intensive
 Expensive dedicated
software

WiFi Technology :Evolution of Wi-Fi showing the
technology’s 15-year history and exponential gains in
throughput, now reaching 3.6 Gbps with 802.11ac (5G). A
10-fold increase in 802.11ac access-point sales has put
enormous pressure on the enterprise.

TYPES OF
SERVERS
SERVERS
File server
Print
server
Application
server
Message
sever
Database
server

TYPES OF SERVERS
 File server: These servers provide the services for storing,
retrieving and moving the data. A user can read, write,
exchange and manage the files with the help of file servers.
 Printer server: The printer server is used for controlling and
managing printing on the network. It also offers the fax
service to the network users.
 Application server: The expensive software and additional
computing power can be shared by the computers in a
network with he help of application servers.
 Message server: It is used to co-ordinate the interaction
between users, documents and applications. The data can be
used in the for of audio, video, binary, text or graphics.
 Database server: It is a type of application server. It allows
the uses to access the centralised strong database.

Applications
e-mail
Searchable Data (Web Sites)
e-Commerce
News Groups
Internet Telephony (VoIP)
Video Conferencing
Chat Groups
Instant Messengers
Internet Radio
e-marketing
e-learning/education/library
e-banking etc.
FUTURE TRENDS RKP_Internet_part_II.pptx

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Rkp internet part i

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