Transcript Lecture 7 - IITK - Indian Institute of Technology Kanpur

INTRODUCTION TO
COMPUTER NETWORKS
(LAN, MAN & WAN)
Navpreet Singh
Computer Centre
Indian Institute of Technology Kanpur
Kanpur INDIA
(Ph : 2597371, Email : [email protected])
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Content
Content
Introduction to Computer Networks
Physical Media
Overview Of Network Architectures
Campus Networks
Enterprise Networks
Internet
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Introduction to Computer Networks
Computer Networks
Computer
network
connects two or more
autonomous computers.
The computers can be
geographically located
anywhere.
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Introduction to Computer Networks
LAN, MAN & WAN
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)
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Introduction to Computer Networks
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, Chat, VoIP
Message broadcast
Remote computing
Distributed processing (GRID Computing)
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Introduction to Computer Networks
Network Topology
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.
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QUESTIONS?
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Introduction to Computer Networks
Network Components
Physical Media
Interconnecting Devices
Computers
Networking Software
Applications
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Introduction to Computer Networks
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).
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Introduction to Computer Networks
Networking Devices
HUB, Switches, Routers,
Wireless Access Points,
Modems etc.
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Introduction to Computer Networks
Computers: Clients and Servers
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.
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Introduction to Computer Networks
Networking Protocol: TCP/IP
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Introduction to Computer Networks
Applications
E-mail
Searchable Data (Web Sites)
E-Commerce
News Groups
Internet Telephony (VoIP)
Video Conferencing
Chat Groups
Instant Messengers
Internet Radio
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QUESTIONS?
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Physical Media
PHYSICAL MEDIA
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Physical Media
Physical Media
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Physical Media
Physical Media
Copper
Coaxial Cable - Thick or Thin
Unshielded Twisted Pair - CAT 3,4,5,5e&6
Optical Fiber
Multimode
Singlemode
Wireless
Short Range
Medium Range (Line of Sight)
Satellite
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Physical Media
Copper Media: Coaxial Cable
Coaxial cable is a coppercored cable surrounded
by a heavy shielding and
is used to connect
computers in a network.
Outer conductor shields
the inner conductor from
picking up stray signal
from the air.
High bandwidth but lossy
channel.
Repeater is used to
regenerate the weakened
signals.
Category
Impedance
Use
RG-59
75 W
Cable TV
RG-58
50 W
Thin
Ethernet
RG-11
50 W
Thick
Ethernet
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Physical Media
Copper Media: Twisted Pair
Twisted-pair is a type of
cabling that is used for
telephone communications
and most modern Ethernet
networks.
A pair of wires forms a
circuit that can transmit
data. The pairs are twisted
to
provide
protection
against crosstalk, the noise
generated by adjacent pairs.
There are two basic types,
shielded twisted-pair (STP)
and unshielded twisted-pair
(UTP).
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Physical Media
Unshielded Twisted Pair (UTP)
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Physical Media
Unshielded Twisted Pair (UTP)
Consists of 4 pairs (8 wires) of
insulated copper wires typically
about 1 mm thick.
The wires are twisted together in a
helical form.
Twisting reduces the interference
between pairs of wires.
High bandwidth and High attenuation
channel.
Flexible and cheap cable.
Category rating based on number of
twists per inch and the material used
CAT 3, CAT 4, CAT 5, Enhanced CAT
5, CAT 6 and now CAT 6+.
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QUESTIONS?
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Physical Media
Fiber Media
Optical fibers use light
to send information
through the optical
medium.
It uses the principal of
total internal reflection.
Modulated
light
transmissions are used
to transmit the signal.
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Physical Media
Total Internal Reflection
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Physical Media
Fiber Media
Light travels through the optical media by the way of
total internal reflection.
Modulation scheme used is intensity modulation.
Two types of Fiber media :
Multimode
Singlemode
Multimode Fiber can support less bandwidth than
Singlemode Fiber.
Singlemode Fiber has a very small core and carry
only one beam of light. It can support Gbps data
rates over > 100 Km without using repeaters.
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Physical Media
Single and Multimode Fiber
Single-mode fiber
Carries light pulses
along single path
Uses
Laser
Light
Source
Multimode fiber
Many pulses of light
generated by LED
travel
at
different
angles
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Physical Media
Fiber-Optic Cable
Contains one or several
glass fibers at its core
Surrounding the fibers is
a layer called cladding
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Physical Media
Fiber Optic Cable
FO Cable may have 1 to
over 1000 fibers
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QUESTIONS?
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Physical Media
Wireless Media
Very useful in difficult
terrain where cable
laying is not possible.
Provides mobility to
communication nodes.
Right of way and cable
laying costs can be
reduced.
Susceptible to rain,
atmospheric variations
and
Objects
in
transmission path.
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Physical Media
Wireless Media
Indoor : 10 – 50m : BlueTooth, WLAN
Short range Outdoor : 50 – 200m: WLAN
Mid Range Outdoor : 200m – 5 Km : GSM, CDMA,
WLAN Point-to-Point, Wi-Max
Long Range Outdoor : 5 Km – 100 Km : Microwave
Point-to-Point
Long Distance Communication : Across Continents :
Satellite Communication
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Physical Media
Wireless LAN
PC
Access Point
Internet
Router
Switch
PC
Access Point
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Physical Media
Terrestrial Microwave
Microwaves do not
follow the curvature of
earth
Line-of-Sight
transmission
Height
allows
the
signal to travel farther
Two frequencies for
two
way
communication
Repeater is used to
increase the distance
Hop-by-Hop
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Physical Media
Satellite Communication
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QUESTIONS?
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