This document provides an overview of computer networking concepts including different network topologies, transmission media, and network components. It defines key networking terms like local area network (LAN), metropolitan area network (MAN), wide area network (WAN), and personal area network (PAN). Different network topologies like bus, star, ring, and mesh are described. Common transmission media include coaxial cable, twisted pair cable, optical fiber, and wireless transmission. Network components such as hubs, switches, routers, bridges, and gateways are also explained.

1. COMPUTER
NETWORKING
HIMANT PRASANSU, CLASS 9 ‘C’ ROLL NUMBER- 7

2. A network consists of 2 or more
computers connected together,
and they can communicate and
share resources (e.g. information)

3. • Communications – activity associated
with distributing or exchanging
information
• Telecommunications – technology of
communications at a distance that
permits information to be created any
where and used everywhere with little
delay
A network is a way to get “stuff”
between 2 or more “things”
Examples: Mail, phone system,
conversations, railroad system,
highways and roads

4. •Must have a
message
•Message must
have a
t r ansmi t t er
•Message must
have a medi um
•Message must be

5. Source System Destination System
Sour c e  Tr a ns mi t t e r  Tr a ns mi s s i on  Re c e i ve r 
De s t i na t i on
1 2 3 4 5
Wor ks t a t i on/ PC Me di um Wor ks t a t i on/ PC

6. Es s e nt i a l s f or Ne t wor k
• Text input information
• Input data digital bit
stream
• Transmitted analog
signal
• Received analog signal
• Output data digital bit
stream
• Text output information

7. A t ypi c a l ne t wor k

8. TOPOLOGI ES

9. Bus Topol ogy
Bus: each node is daisy-chained
(connected one right after the other)
along the same backbone. Information
sent from a node travels along the
backbone until it reaches its destination
node. Each end of a bus network must
be terminated with a resistor to keep the

10. Ri ng Topol ogy
Similar to a bus network, rings have
nodes daisy chained, but the end of the
network in a ring topology comes back
around to the first node, creating a
complete circuit. Each node takes a turn
sending and receiving information
through the use of a token. The token
along with any data is sent from the first
node to the second node which extracts
the data addressed to it and adds any
data it wishes to send. Then second
node passes the token and data to the
third node, etc. until it comes back
around to the first node again. Only the
node with the token is allowed to send
data . All other nodes must wait for the
token to come to them.

11. St a r Topol ogy
• In a star network, each node is
connected to a central device
called a hub. The hub takes a
signal that comes from any
node and passes it along to all
the other nodes in the network
• A hub does not perform any
type of filtering or routing of
the data
• A hub is a junction that joins
all the different nodes together

12. St a r - Bus Topol ogy
Prob. Most common topology
used today. Combines elements
of the star and bus topologies to
create a versatile network
environment
Nodes in particular areas are
connected to hubs (and create
star topology), and hubs are
connected together along the
network backbone (like a bus
network)
Often you have stars nested
within stars

13. Me s h Topol ogy
It is also called a
point-to-point
topology
Each device is
connected directly to
all other network
devices
It provides fault
tolerance
It is only found in
wide area networks

14. Ot he r ne t wor k t opol ogi e s
Some basic network
topologies not
previously mentioned:
•One-to-one
•Hierarchical
•Hybrid
•Client-server
•Multiple nodes

15. TYPES OF
NETWORK

16. Ne t wor k c onf i gur a t i on
Classification based on
how computers behave in
a network
Two classifications are
•Peer-to-Peer
network
•Server based
network

17. Pe e r - t o- Pe e r ne t wor k
•Nodes provide and
request services
•User in each node
administers
resources
•No extra investment
•Easy to setup
•Very weak security
•Additional load on

18. Server based network
•Designated
computer to
administer
•Resources
centralized
•Supports larger
networks
•Strong security
•Expensive

19. Advantages of peer-to-peer networks:
• Low cost
• Simple to configure
• User has full accessibility of the computer
Di sadvant ages of peer- t o- peer net works:
• May have duplication in resources
• Difficult to uphold security policy
• Difficult to handle uneven loading
Where peer-to-peer network is appropriate:
• 10 or less users
• No specialized services required
• Security is not an issue
• Only limited growth in the foreseeable
future

20. Cl i e nt s a nd Se r ve r s
Network Clients (Workstation)
Computers that request network resources or services
Network Servers
Computers that manage and provide network resources and
services to clients
Usually have more processing power, memory and hard disk
space than clients
Run Network Operating System that can manage not only
data, but also users, groups, security, and applications on the
network
Servers often have a more stringent requirement on its
performance and reliability

21. Advant ages of cl i ent / server
net works
• Facilitate resource sharing – centrally administrate
and control
• Facilitate system backup and improve fault tolerance
• Enhance security – only administrator can have access
to Server
• Support more users – difficult to achieve with peer-
to-peer networks●
Di s a dva nt a ge s of
c l i e nt / s e r ve r
ne t wor ks
●High cost for Servers
●Need expert to configure the
network
●Introduce a single point of failure
to the system

22. NETWORKI NG
MEDI A AND
COMPONENTS

23. Coa xi a l c a bl e
• Widely installed for use in business and corporation
Ethernet and other types of LANs.
• Consists of inter copper insulator covered by cladding
material, and then covered by an outer jacket.
• Physical Descriptions.
 Inner conductor is solid copper
metal
Separated by insulating material
 Outer conductor is braided shielded
(ground)
 Covered by sheath material

24. Appl i cat i ons:
•TV distribution (cable TV); long distance telephone transmission;
short run computer system links.
•Local area networks.
Transmi ssi on charact eri st i cs:
• Can transmit analog and digital signals
• Usable spectrum for analog signaling is about 400
MHz
• Amplifier needed for analog signals for less than 1 Km
and less distance for higher frequency
• Repeater needed for digital signals every Km
or less distance for higher data rates
• Operation of 100’s Mb/s over 1 Km

25. Twi s t e d Pa i r Ca bl e s
Physi cal descri pt i on:
• Each wire with copper conductor
• Separately insulated wires
• Twisted together to reduce cross talk
• Often bundled into cables of two or four twisted pairs
• If enclosed in a sheath then is shielded twisted pair (STP) otherwise
often for home usage unshielded twisted pair (UTP). Must be shield
from voltage lines
Appl i cat i on:
• Common in building for digital signaling used at speed of 10’s
Mb/s (CAT3) and 100Mb/s (CAT5) over 100s meters.
• Common for telephone interconnection at home
and office buildings
• Less expensive medium; limited in distance,
bandwidth, and data rate

26. Category Maximum data
rate
Usual application
CAT 1 Less than 1 Mbps analog voice (plain old telephone
service) Integrated Services
Digital Network Basic Rate
Interface in ISDN Doorbell wiring
CAT 2 4 Mbps Mainly used in the IBM Cabling
System for token ring networks
CAT 3 16 Mbps Voice and data on 10BASE-T
Ethernet (certify 16Mhz signal)
CAT 4 20 Mbps Used in 16Mbps Token Ring
Otherwise not used much
CAT 5 100 Mbps 100 Mbps TPDDI
Ca t e gor i e s of Twi s t e d Pa i r s
Ca bl i ng Sys t e m

27. Opt i c a l Fi be r s
Physi cal Descri pt i on:
• Glass or plastic core of optical fiber = 2to125 µm.
• Cladding is an insulating material.
• Jacket is a protective cover.
• Laser or light emitting diode provides transmission light source.
Appl i cat i ons:
• Long di s t a nc e t e l e c ommuni c a t i on.
• Gr e a t e r c a pa c i t y; 2 GB/ s ove r 10’ s of Km.
• Sma l l e r s i z e a nd l i ght e r we i ght .
• Lowe r a t t e nua t i on ( r e duc t i on i n s t r e ngt h of
s i gna l ) .

28. ●
Electromagnetic isolation – not effected by external
electromagnetic environment. Aka more privacy.
•Greater repeater spacing fewer repeaters, reduces line
regeneration cost.
• Multimode fiber is optical fiber that is designed to carry multiple light
rays or modes concurrently, each at a slightly different reflection angle
within the optical fiber core.
used for relatively short distances because the modes tend to disperse
over longer lengths (this is called modal dispersion).
• For longer distances, single mode fiber (sometimes called monomode)
fiber is used. In single mode fiber a single ray or mode of light act as a
carrier.

29. Wi r e l e s s Tr a ns mi s s i on
Frequency range ( l i ne of si ght ) :
• 26 GHz to 40 GHz: for microwave with highly directional beam as possible.
• 30 MHz to 1 GHz: for Omni directional applications.
• 300MHz to 20000 GHz: for infrared spectrum; used for point to point and
multiple point application (line of sight).
Physical applications:
• Terrestrial microwave – long haul telecommunication service (alternative to
coaxial or optical fiber).
• Few amplifier and repeaters.
• Propagation via towers located without blockage from trees,
etc (towers less than 60 miles apart).

30. • Satellite is a microwave relay station.
• Geostationary orbit (22,000 miles) and low orbit (12000 miles).
• Satellite ground stations are aligned to the space satellite, establishes a link,
broadcast at a specified frequency. Ground station normally operate at a number of
frequencies – full duplex.
• Satellite space antenna is aligned to the ground station establishes a link and
transmits at the specified frequency. Satellite are capable of transmitting at multiple
frequencies simultaneously, full duplex..
• To avoid satellites from interfering with each other, a 4 degree separation is required
for 4/6 GHz band and 3 degree for 12/14 GHz band. Limited to 90 satellites.
• Disadvantage: not satellite repair capability; greater delay and
attenuation problems

31. Wi r e l e s s LAN
• Wireless LAN.
• Hyper LAN (European standard; allow
communication at up to 20 Mbps in 5
GHz range of the radio frequency (RF)
spectrum.
• Hyper LAN/2 operate at about 54
Mbps in the same RF band.

32. Net work
Compone
nt s

33. Hubs
•A hub is the place where data converges
from one or more directions and is
forwarded out in one or more directions.
•Seen in local area networks.

34. Ga t e wa ys
• A gateway is a network point that
acts as an entrance to another
network. On the internet, in terms of
routing, the network consists of
gateway nodes and host nodes
• Host nodes are computer of network
users and the computers that serve
contents (such as Web pages)
• Gateway nodes are computers that
control
traffic within your company’s network

35. Rout e r s
• A router is a device or a software in a
computer that determines the next network
point to which a packet should be
forwarded toward its destination
• Allow different networks to communicate
with each other
• A router creates and maintain a table of the
available routes and their conditions and
uses this information along with distance
and cost algorithms to determine the best
route for a given packet
• A packet will travel through a number of
network points with routers before arriving

36. Br i dge
•A bridge is a product that connects
a local area network (LAN) to
another local area network that
uses the same protocol (for
example, Ethernet or token ring)
•A bridge examines each message
on a LAN, "passing" those known
to be within the same LAN, and
forwarding those known to be on

37. Swi t c he s
•Allow different nodes of a network to
communicate directly with each other
•Allow several users to send information
over a network at the same time without
slowing each other down

38. TYPES OF
NETWORK

39. Loc a l Ar e a Ne t wor k ( LAN)
A Local Area Network (LAN) is a relatively small network that
is confined to a small geographic area, such as a single office
or a building. Laptops, desktops, servers, printers, and other
networked devices that make up a LAN are located relatively
close to each other. A key characteristic is that all of the
equipment that comprises a LAN, is owned by a single entity.

40. Me t r opol i t a n Ar e a Ne t wor k
The term Metropolitan Area Network (MAN) is typically used to
describe a network that spans a citywide area or a town. MANs
are larger than traditional LANs and predominantly use high-
speed media, such as fiber optic cable, for their backbones.
MANs are common in organizations that need to connect several
smaller facilities together for information sharing. This is often the
case for hospitals that need to connect treatment facilities,
outpatient facilities, doctor's offices, labs, and research offices for
access to centralized patient and treatment information. MANs
share many of the same security threats as LANs, but on a larger
scale. The plight of an administrator in a central location granting
access to countless offices that are scattered within a city is a
difficult one that demands strict access control
mechanisms to protect against unauthorized
information access.

41. MAN Ar c hi t e c t ur e

42. Wi de Ar e a Ne t wor k
A Wide Area Network (WAN) covers a significantly larger
geographic area than LANs or MANs. A WAN uses public
networks, telephone lines, and leased lines to tie together smaller
networks such as LANs and MANs over a geographically
dispersed area. Connecting devices in different geographic areas
together for information sharing, WANs are an important piece
of enterprise networks. For example, consider the Visa Net
global network used by Visa International. The Visa Net network
connects locations throughout 150 countries to validate and debit
credit-card transactions at over 24 million locations. By providing
security and simplicity over a standard-based WAN architecture,
Visa International relies on their network infrastructure to
provide reliable access to merchants who accept Visa
credit cards for transactions.

43. WAN Ar c hi t e c t ur e

44. Pe r s ona l Ar e a Ne t wor k
A more recent term used to describe a type of network is a Personal Area
Network (PAN). PAN networks are usually wireless, established in an on-
demand or ad-hoc fashion when needed to communicate between two or more
devices. PAN networks can be used between devices owned by two different
parties, or between two devices owned by one person, such as a PDA and a
laptop or mobile phone. These networks are usually characterized as short-range,
often limited to 10 meters or less in range.
An example of a PAN technology is Bluetooth wireless networking. Bluetooth is
designed as a cable-replacement technology, allowing users to discard the serial
and USB cables used by many of today's peripheral devices and rely on a
Bluetooth PAN for communication. Bluetooth PANs support up to 7 devices in a
single network and can be used for proprietary protocols (such as PDA
synchronization) or standards-based protocols, including Internet
access over IP and the Bluetooth Network Encapsulation Protocol
(BNEP).

45. PAN Ar c hi t e c t ur e

46. THANK
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