2. Lesson 2âNetworking BASICS2
Types of Networks
âą There are two types of
networks by which
information is transmitted:
â circuit switched networks
â packet switched networks
3. Lesson 2âNetworking BASICS3
Circuit Switched Network
âą There is a dedicated and direct physical
connection between sender and receiver.
âą No other transmissions can take place while
the connection is active.
âą Once the transmission is ended, other
connections can be made with other devices.
âą It is ideal for voice communications because
there are no interruptions from other devices
or delays.
4. Lesson 2âNetworking BASICS4
Packet Switched Network
âą This network requires data transmission be broken
into smaller units called packets.
âą Each packet is sent independently through the
network.
âą It is used for data transmission because data is not
as time-sensitive as voice communication.
âą It allows multiple devices to share one line or
frequency.
âą It facilitates error correction.
5. Lesson 2âNetworking BASICS5
Signaling Techniques
âą There are two ways that a
signal is sent across a
network medium:
â baseband signaling
â broadband signaling
6. Lesson 2âNetworking BASICS6
Baseband Signaling
âą Sends one data signal across the network
media
âą Entire capacity of the media is used for the
one data signal
âą Signals are transmitted in a digital format
âą Many devices can send and receive across
the medium, but only one at a time
8. Lesson 2âNetworking BASICS8
Broadband Signaling
âą Divides the cable into several different
channels
âą Signals are transmitted at different
frequencies in an analog mode
âą Allows many different signals to be sent
simultaneously on a single cable
âą Signal sent in only one direction
âą Used for computer network data
transmissions
10. Lesson 2âNetworking BASICS10
Factors Affecting Transmissions
âą The flow of a signal down the
network media can become
distorted.
âą Common types of distortions are
attenuation and interference.
12. Lesson 2âNetworking BASICS12
Interference
âą Interference is caused when a strong external signal
interferes with a signal.
âą Radio frequency interference (RFI) - interference
caused by broadcast signals from a radio or
television transmitter.
âą Electromagnetic interference (EMI) - motor or
source of intense electrical activity creates an
electromagnetic signal that interferes with a data
signal.
âą Near end crosstalk (NEXT) and Far end crosstalk
(FEXT) - interference from another data signal being
transmitted on adjacent wire.
17. Lesson 2âNetworking BASICS17
Fiber Optic
âą This cable uses a thin cylinder of glass to
send light impulses.
âą The cable consists of a strand of glass (core)
surrounded by a glass tube (cladding).
âą Single mode - one light source flashes a light
down the cable.
âą Multimode - supports many simultaneous
light transmissions.
19. Lesson 2âNetworking BASICS19
Wireless
âą Transmission is sent and received through
invisible waves
âą Less expensive than copper or fiber optic
lines.
âą Allows the user to move freely around the
office or campus and still remain connected
to the network
âą Fastest-growing segment of network media
today
20. Lesson 2âNetworking BASICS20
Wireless Transmissions
âą Infrared transmits data using infrared (IR)
light.
âą IR shares many of the same properties as
visible light .
âą Radio frequency signals can be transmitted
over radio waves similar to local radio station
transmissions.
âą The signal comes in at a lower power level
and does not reach as far.
21. Lesson 2âNetworking BASICS21
Network Interface Card
âą The NIC serves as the connection between
the personal computer and the network
media.
âą It connects to the computer on its base by
plugging into an expansion slot of the
computer.
âą Another connection is accessible from the
outside of the computer and has connections
for the cables to plug into the network.
22. Lesson 2âNetworking BASICS22
Network Interface Card
âą Changes from parallel to
serial transmission
âą Creates packets
âą Determines when to send
âą Transmits packet