This document provides an overview of computer networks and connectivity. It discusses how communication systems allow data to be transmitted between computers through various connection methods and channels. Wireless connectivity has increased dramatically with technologies like Wi-Fi, Bluetooth, and cellular networks. The document also examines network topologies, architectures, security measures, and different types of organizational networks.

1. COMPUTER EDUCATION 9
MODULE 4
Network Connectivity
Prepared By: Engr. Jeremy M. Flores

2. COMMUNICATION
We live in a truly connected
society. We can communicate
almost instantaneously with
others worldwide.

3. COMMUNICATION
As the power and flexibility of our
communication systems have
expanded, the sophistication of
the networks that support these
systems has become increasingly
critical and complex.

4. COMMUNICATION
Computer communication is
the process of sharing data,
programs, and information
between two or more
computers.

5. COMMUNICATION
Electronic Mail
Texting and Messaging
Internet Telephone
Electronic Commerce

6. CONNECTIVITY
Connectivity is a concept
related to using computer
networks to link people and
resources.

7. THE WIRELESS REVOLUTION
The single most dramatic
change in connectivity and
communications in the past
few years.

8. THE WIRELESS REVOLUTION
It refers to the widespread use
of mobile devices like
smartphones and tablets with
wireless Internet connectivity.

9. THE WIRELESS REVOLUTION
So, what’s the revolution?
Today’s mobile computers
support E-mail, Web access,
and variety of Internet
applications.

10. THE WIRELESS REVOLUTION
Most experts say that the
Wireless Revolution is just in its
beginning phase.

11. COMMUNICATION SYSTEMS
It is an electronic systems that
transmit data from one
location to another, whether
wired or wireless.

12. COMMUNICATION SYSTEMS
Four Basic Elements
Sending / Receiving Devices
Connecting Devices
Data Transmission Specification
Communication Channel

13. COMMUNICATION SYSTEMS

14. COMMUNICATION SYSTEMS
Sending / Receiving Devices
These are often a computer or
specialized communication
devices that originate and
accept messages in the form of
data, information, and/or
instructions.

15. COMMUNICATION SYSTEMS
Connecting Devices
These devices act as an
interface between the sending
and receiving devices and
communication channel.

16. COMMUNICATION SYSTEMS
Connecting Devices
They convert outgoing messages
into packets that can travel
across the communication
channel and reverse the process
for incoming messages.

17. COMMUNICATION SYSTEMS
Data Transmission Specification
These are rules and procedures
that coordinate the sending and
receiving devices by precisely
defining how the message will be
sent across the communication
device.

18. COMMUNICATION SYSTEMS
Communication Channel
This is the actual connecting or
transmission medium that carries
the message. It can be physical
wire or cable, or it can be
wireless.

19. COMMUNICATION CHANNELS
Communication Channels are
essential elements of every
communication system. These
channels carry out the data
from one computer to another.

20. COMMUNICATION CHANNELS
Two Categories
Physical Connection
Wireless Connection

21. COMMUNICATION CHANNELS
Physical Connection
It uses a solid medium to
connect sending and
receiving devices.

22. COMMUNICATION CHANNELS

23. COMMUNICATION CHANNELS
Twisted-Pair Cable consists of
pair of copper wires that are
twisted together.
Shielded Twisted-Pair (STP)
Unshielded Twisted-Pair (UTP)

24. COMMUNICATION CHANNELS
Coaxial Cable, a high
frequency transmission cable,
replaces the multiple wires of
telephone lines with a single
solid-copper core.

25. COMMUNICATION CHANNELS
Fiber Optic Cable transmits
data as pulses of light through
tiny tubes of glass, and rapidly
replacing Twisted-Pair cable
telephone lines.

26. COMMUNICATION CHANNELS
Fiber Optic Cable has over
26,000 times the transmission
capacity of Twisted-Pair Cable.
Compared to Coaxial Cable, it
is lighter, faster, and more
reliable in transmitting data.

27. WIRELESS CONNECTIONS
They move data through the
air and use radio waves to
communicate.

28. WIRELESS CONNECTIONS
Bluetooth
Wireless Fidelity (Wi-Fi)
Microwave
WiMax
Long Term Evolution (LTE)
Satellite

29. WIRELESS CONNECTIONS
Bluetooth is a short range
communication standard that
transmits data over short
distances of up to
approximately 33 feet.

30. WIRELESS CONNECTIONS
Wireless Fidelity (Wi-Fi) uses
high-frequency radio signals to
transmit data. Most home and
business wireless networks use
Wi-Fi.

31. WIRELESS CONNECTIONS
Microwave communications uses
high-frequency radio waves. It is
sometimes referred to as line-of-
sight communications because it
can only travel in a straight line.

32. WIRELESS CONNECTIONS
WiMax, Worldwide
Interoperablity for Microwave
Access, is a new standard that
extends the range of Wi-Fi
networks using microwave
connections.

33. WIRELESS CONNECTIONS
LTE, Long Term Evolution, the
newest wireless standard,
promises to provide greater
speed and quality transmission
in the near future.

34. WIRELESS CONNECTIONS
Satellite Communication uses
satellites orbiting about 22,000
miles above the earth as
microwave relay stations.

35. WIRELESS CONNECTIONS
Many of these are offered by
Intelsat, the International
Telecommunications Satellite
Consortium, owned by 114
governments and forms a
worldwide communication
system.

36. WIRELESS CONNECTIONS
UPLINK is a term relating to
sending data to satellite.
DOWNLINK refers to receiving
data from satellite.

37. WIRELESS CONNECTIONS
Global Positioning System
(GPS) is one of the most
interesting application of
Satellite Communications.

38. CONNECTION DEVICES
Telephones typically send and
receive Analog Signals.
Computers send and receive
Digital Signals.

39. ANALOG AND DIGITAL SIGNALS

40. MODEMS
The word MODEM is short for
MOdulator-DEModulator.
It enables digital microcomputers
to communicate across different
media.

41. MODEMS
Modulation is the process of
converting from digital to analog.
Demodulation is the process of
converting from analog to digital.

42. TRANSFER RATE
This is the speed by which
modems transmit data.

43. MODEMS
Four Commonly Used Modems
Telephone
Digital Subscriber Line (DSL)
Cable Modem
Wireless Modem

44. MODEMS

45. MODEMS
A Telephone Modem is used to
connect a computer directly to
a telephone line. It can either
be internal or external.

46. MODEMS
A Digital Subscriber Line
Modem uses standard phone
lines to create a high-speed
connection directly to your
phone company’s office.

47. MODEMS
A Cable Modem uses the
same coaxial cable as your
television and creates a high-
speed connection.

48. MODEMS
A Wireless Modem, also known
as WWAN (Wireless Wide Area
Network), usually uses a small
plug-in USB or ExpressCard
device that provides very
portable wireless connectivity.

49. CONNECTION SERVICES
Dial-Up Service
Digital Subscriber Line (DSL)
Asymmetric DSL (ADSL)
Cable Service
Satellite Connection Service
Cellular Service

50. DATA TRANSMISSION
Bandwidth is a measurement of
the width or capacity of the
communications channel.
Effectively, it means how much
information can move across the
communication channel in a
given amount of time.

51. DATA TRANSMISSION
Four Categories of Bandwidth
Voiceband
Medium Band
Broadband
Baseband

52. DATA TRANSMISSION
Voiceband, also known as low
bandwidth, is used for standard
telephone communication.

53. DATA TRANSMISSION
Medium Band is used in special
leased lines to connect midrange
computers and mainframes as
well as to transmit data over long
distances up to a very high speed
transfer rate.

54. DATA TRANSMISSION
Broadband is widely used for DSL,
cable, and satellite connections
to the Internet. Several users san
simultaneously use a single
broadband connection for high-
speed data transfer.

55. DATA TRANSMISSION
Baseband is widely used to
connect individual computers
that are located close to one
another. Though it is able to
support high-speed transmission,
it can only carry a single signal at
one time.

56. PROTOCOLS
Protocols are sets of
communication rules for the
exchange of information.
HTTP and HTTPS
TCP/IP

57. PROTOCOLS
TCP/IP (Transmission Control
Protocol / Internet Protocol)
involves identifying sending and
receiving devices, and breaking
information into small parts for
transmission across the Internet.

58. NETWORKS
A Computer Network is a
communication system that
connects two or more
computers so that they can
exchange information and
share resources.

59. SPECIALIZED NETWORKS TERMS
Node / Client / Server
Directory Server / Host
Router / Switch
Network Interface Card (NIC)
Network Operating System (NOS)
Network Administrator

60. SPECIALIZED NETWORKS TERMS
Node is any device that is
connected to a network. It
could be a computer, printer,
or data storage device.

61. SPECIALIZED NETWORKS TERMS
Client is a node that requests
and uses resources available
from other nodes. Typically, a
client is a microcomputer.

62. SPECIALIZED NETWORKS TERMS
Server is a node that shares
resources with other nodes.
Depending on the task they may
be called an application server,
communication server, file server,
printer server, database server, or
web server.

63. SPECIALIZED NETWORKS TERMS
Types of Server
Centralized Server
Dedicated Server

64. SPECIALIZED NETWORKS TERMS
Directory Server is a
specialized or dedicated
server that manages
resources, such as user
accounts, for an entire
network.

65. SPECIALIZED NETWORKS TERMS
Host is any computer system
that can be accessed over a
network.

66. SPECIALIZED NETWORKS TERMS
Router a node that forwards or
routes data packets from one
network to their destination in
another network.

67. SPECIALIZED NETWORKS TERMS
Switch is a central node that
coordinates the flow of data by
sending messages directly
between sender and receiver
nodes.

68. SPECIALIZED NETWORKS TERMS
A hub previously filled the role
of a switch by sending a
received message to all
connected nodes, rather than
just the intended node.

69. SPECIALIZED NETWORKS TERMS
A Network Interface Card
(NIC) is an expansion card
located within the system unit
that connects the computer to
a network. It is sometimes
referred to as LAN Adapter.

70. SPECIALIZED NETWORKS TERMS
A Network Operating System
(NOS) controls and
coordinates the activities of all
computers and other devices
on a network.

71. SPECIALIZED NETWORKS TERMS
A Network Administrator is a
computer specialist
responsible for efficient
network operations and
implementation of new
networks.

72. NETWORK TYPES
Home Network
Personal Area Network
Local Area Network
Wireless LAN
Metropolitan Area Network
Wide Area Network

73. NETWORK TYPES
Home Network is commonly
used by individuals in their
homes and apartments and
can be connected in a variety
of ways.

74. NETWORK TYPES
Personal Area Network is a
type of wireless network that
works within a very small area,
such as cellphone to headset,
keyboard to cellphones, PDAs
to other PDAs.

75. NETWORK TYPES
Local Area Network is a
computer network with nodes
that are in close physical
proximity, within the same
building for instance.

76. NETWORK TYPES
Wireless LAN is a Local Area
Network that typically uses radio
frequencies to connect
computers and other devices. All
communications pass through
the network’s Wireless Access
Point or Base Station.

77. NETWORK TYPES
Metropolitan Area Network
spans distances up to 100
miles and are frequently used
to link between office buildings
that are located throughout a
city.

78. NETWORK TYPES
Wide Area Network is a
countrywide and worldwide
network, typically spans
distances greater than 100 miles,
and uses microwave relays and
satellites to reach users over long
distances.

79. NETWORK TYPES
The primary differences
between the network types is
the geographic range.

80. NETWORK ARCHITECTURE
Network Architecture
describes how a network is
arranged and how resources
are coordinated and shared.

81. NETWORK ARCHITECTURE
Bus Topology
Ring Topology
Star Topology
Tree Topology
Mesh Topology

82. NETWORK ARCHITECTURE
In Bus Topology, each device
is connected to a common
cable called a bus or
backbone, and all
communications travel along
this bus.

83. NETWORK ARCHITECTURE
In Ring Topology, each device
is connected to two other
devices forming a ring. When a
message is sent, it is passed
around the ring until it reaches
the intended destination.

84. NETWORK ARCHITECTURE

85. NETWORK ARCHITECTURE
In Star Topology, each device is
connected directly to a central
network switch. Whenever a node
sends a message, it is routed to
the switch, which then passes the
message to the recipient.

86. NETWORK ARCHITECTURE

87. NETWORK ARCHITECTURE
In Tree Topology, each device
is connected to a central
node, either directly or through
one or more other devices. It is
also known as Hierarchical
Network.

88. NETWORK ARCHITECTURE

89. NETWORK ARCHITECTURE
In Mesh Topology, each node
is required to have more than
one connection to the other
nodes and does not require a
specific physical layout.

90. NETWORK ARCHITECTURE

91. NETWORK STRATEGIES
Client/Server Network
Peer-to-Peer Network

92. NETWORK STRATEGIES
Client/Server Network uses
central computers to
coordinate and supply
services to other nodes on the
network.

93. NETWORK STRATEGIES

94. NETWORK STRATEGIES
In a Peer-to-Peer (P2P)
Network, nodes have equal
authority and can act as both
client and server.

95. ORGANIZATIONAL NETWORKS
An Intranet is a private network
within an organization that
resembles the Internet.
An Extranet is a private network
that connects more than one
organization.

96. ORGANIZATIONAL NETWORKS

97. NETWORK SECURITY
A firewall consists of hardware
and software that control access
to a company’s intranet and
other internal networks, through a
special software of computer
called Proxy Server.

98. NETWORK SECURITY
Intrusion Detection System
(IDS) works with firewall to
protect and organization’s
network. It can recognize signs
of network attack by pattern
matching and heuristics.

99. NETWORK SECURITY
A Virtual Private Network (VPN)
create a secure private
connection between a remote
user and an organization’s
internal network.