networkmedia presentation1

MODULE 4 NETWORK MEDIA
NETWORK MEDIA

Network media is the actual path over
which an electrical signal travels as it
moves from one component to
another.
NETWORK MEDIA

TWO TYPES OF NETWORK
TRANSMISSION
1.Bounded/Guided Transmission
2. Unbound Transmission
NETWORK MEDIA

1.Bounded/Guided Transmission
Media
It is the transmission media in which
signals are confined to a specific path
using wire or cable. The types of
Bounded/ Guided are twisted-pair
cable, coaxial cable, fiber-optic cable,
and wireless
NETWORK MEDIA

2.Unbound transmission
media extend beyond the limiting
confines of cabling.
They provide an excellent
Communication Networks
alternative for WANS.
NETWORK MEDIA-UNBOUND

2.Unbound transmission media . The
lack of physical restrictions provides
larger bandwidth as well as wide area
capabilities. Unbound media typically
operate at very high frequencies. The
three types of unbound transmission
media are: Radio wave, Micro wave,
Infrared.

Unbound transmission media -
three types of unbound
transmission media are: Radio
wave, Micro wave, Infrared.

1.Radio waves are prevalent
and well understood, we are
just beginning to realize their
enormous potential as a
networking medium. Radio
waves can operate on a single
or multiple frequency bands..

Radiowaves are omni
directional i.e. they travel in
all the directions from the
source. Because of this
property, transmitter and
receiver need not to be
aligned.

1. Radiowaves can penetrate
buildings easily, so they are
widely use for communication
both indoors outdoors.

At high frequencies, radiowaves tends to
travel in straight line and bounce off the
obstacles. They are also absorbed by rain.

Radiowaves me widely used for AM and FM
radio, television, cordless telephone, cellular
phones, paging and wireless LAN.

2. Microwave Transmission
Microwaves have been used in data
communications for a long time. They have a
higher frequency than radio waves and
therefore can handle larger amounts of data.

Microwave transmission is line of sight
transmission. The transmit station must be in
visible contact with the receive station. This
sets a limit on the distance between stations
depending on the local geography. Typically
the line of sight due to the Earth's curvature
is only 50 km to the horizon!

3.Infrared- offers a great unbound
photonic solution. Like fiber-optic
cabling, infrared communications
use light, so they are not bound by
the limitations of electricity.

Infra Red.
Infrared transmission refers to
energy in the region of the
electromagnetic radiation spectrum
at wavelengths longer than those of
visible light, but shorter than those
of radio waves

Infra Red.
Correspondingly,infrared frequencies
are higher than those of microwaves,
but lower than those of visible light.

Bounded/Guided Transmission
Media
SAMPLES / Guided are discussed
below.
NETWORK MEDIA

Twisted-Pair Cable
Twisted-pair cable 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. When electrical current flows through
a wire, it creates a small, circular magnetic field
around the wire.
NETWORK MEDIA

Twisted-Pair Cable
When two wires in an electrical circuit are placed close
together, their magnetic fields are the exact opposite of each
other. Thus, the two magnetic fields cancel each other out.
NETWORK MEDIA

Twisted-Pair Cable
They also cancel out any outside magnetic fields.
Twisting the wires can enhance this cancellation
effect. Using cancellation together with twisting the
wires, cable designers can effectively provide self-
shielding for wire pairs within the network media.
NETWORK MEDIA

Two basic types of twisted-pair cable exist: unshielded
twisted pair (UTP) and shielded twisted pair (STP). The
following sections discuss UTP and STP cable in more
detail.
NETWORK MEDIA

UTP Cable
UTP cable is a medium that is composed of pairs of
wires (see Figure 8-1). UTP cable is used in a variety of
networks. Each of the eight individual copper wires in
UTP cable is covered by an insulating material. In
addition, the wires in each pair are twisted around
each other.
NETWORK MEDIA

Unshielded Twisted-Pair Cable
NETWORK MEDIA

UTP cable often is installed using a
Registered Jack 45 (RJ-45)
connector (see Figure 8-2). The RJ-
45 is an eight-wire connector used
commonly to connect computers
onto a local-area network (LAN),
especially Ethernets.
NETWORK MEDIA

Although UTP was once considered to be
slower at transmitting data than other types of
cable, this is no longer true. In fact, UTP is
considered the fastest copper-based medium
today.
NETWORK MEDIA

The following summarizes the features of UTP
cable:
Speed and throughput—10 to 1000 Mbps
Average cost per node—Least expensive
Media and connector size—Small
Maximum cable length—100 m (short)
NETWORK MEDIA

Commonly used types of UTP cabling are as follows:
Category 1—Used for telephone communications. Not suitable
for transmitting data.
Category 2—Capable of transmitting data at speeds up to 4
megabits per second (Mbps).
Category 3—Used in 10BASE-T networks. Can transmit data at
speeds up to 10 Mbps.
NETWORK MEDIA

Commonly used types of UTP cabling are as follows:
Category 4—Used in Token Ring networks. Can transmit data at
speeds up to 16 Mbps.
Category 5—Can transmit data at speeds up to 100 Mbps.
Category 5e —Used in networks running at speeds up to 1000
Mbps (1 gigabit per second [Gbps]).
Category 6—Typically, Category 6 cable consists of four pairs of
24 American Wire Gauge (AWG) copper wires. Category 6 cable
is currently the fastest standard for UTP.
NETWORK MEDIA

Shielded Twisted-Pair Cable
Shielded twisted-pair (STP) cable combines the
techniques of shielding, cancellation, and wire
twisting. Each pair of wires is wrapped in a metallic foil
The four pairs of wires then are wrapped in an overall
metallic braid or foil, usually 150-ohm cable.
NETWORK MEDIA

Shielded Twisted-Pair Cable
Shielded twisted-pair -As specified for use in Ethernet
network installations, STP reduces electrical noise
both within the cable (pair-to-pair coupling, or
crosstalk) and from outside the cable
. STP usually is installed with STP data connector,
which is created especially for the STP cable. However,
STP cabling also can use the same RJ connectors that
UTP uses.
NETWORK MEDIA

Although STP prevents interference better than
UTP, it is more expensive and difficult to install.
In addition, the metallic shielding must be
grounded at both ends.
NETWORK MEDIA

If it is improperly grounded, the shield acts like
an antenna and picks up unwanted signals.
Because of its cost and difficulty with
termination, STP is rarely used in Ethernet
networks.
NETWORK MEDIA

STP is primarily used in Europe.
The following summarizes the features of STP
cable:
Speed and throughput—10 to 100 Mbps
Average cost per node—Moderately expensive
Media and connector size—Medium to large
Maximum cable length—100 m (short)
NETWORK MEDIA

When comparing UTP and STP, keep the
following points in mind:
The speed of both types of cable is usually
satisfactory for local-area distances.
These are the least-expensive media for data
communication.
NETWORK MEDIA

UTP is less expensive than STP.
Because most buildings are already wired with
UTP, many transmission standards are adapted
to use it, to avoid costly rewiring with an
alternative cable type.
NETWORK MEDIA

Coaxial Cable
Coaxial cable consists of a hollow outer
cylindrical conductor that surrounds a single
inner wire made of two conducting
elements.
NETWORK MEDIA

Coaxial Cable
. One of these elements, located in
the center of the cable, is a copper
conductor. Surrounding the copper
conductor is a layer of flexible
insulation.
NETWORK MEDIA

Coaxial cable supports 10 to 100
Mbps and is relatively inexpensive,
although it is more costly than UTP on a per-unit
length. However, coaxial cable can be cheaper for
a physical bus topology because less cable will be
needed.
NETWORK MEDIA

Coaxial cable can be cabled over longer distances than
twisted-pair cable. For example, Ethernet can run
approximately 100 meters (328 feet) using twisted-
pair cabling. Using coaxial cable increases this distance
to 500m (1640.4 feet).
NETWORK MEDIA

Fiber Optics is sending signals down hair-thin strands
of glass or plastic fiber. The light is “guided” down the
center of the fiber called the “core”. The core is
surrounded by a optical material called the “cladding”
that traps the light in the core using an optical
technique called “total internal reflection.”
NETWORK MEDIA

Fiber Optics The core and cladding are usually made of
ultra-pure glass. The fiber is coated with a protective
plastic covering called the “primary buffer coating”
that protects it from moisture and other damage.
More protection is provided by the “cable” which has
the fibers and strength members inside an outer
covering called a “jacket”.
NETWORK MEDIA

NETWORK MEDIA
Media Type Maximum Segment
Length
Speed Cost Advantages Disadvantages
UTP 100 m 10 Mbps to 1000
Mbps
Least expensive Easy to install; widely
available and widely
used
Susceptible to
interference; can
cover only a limited
distance
STP 100 m 10 Mbps to 100 Mbps More expensive than
UTP
Reduced crosstalk;
more resistant to EMI
than Thinnet or UTP
Difficult to work with;
can cover only a
limited distance
Coaxial 500 m (Thicknet)
185 m (Thinnet)
10 Mbps to 100 Mbps Relatively
inexpensive, but
more costly than UTP
Less susceptible to
EMI interference than
other types of copper
media
Difficult to work with
(Thicknet); limited
bandwidth; limited
application (Thinnet);
damage to cable can
bring down entire
network
Fiber-Optic 10 km and farther
(single-mode)
2 km and farther
(multimode)
100 Mbps to 100
Gbps (single mode)
100 Mbps to 9.92
Gbps (multimode)
Expensive Cannot be tapped, so
security is better; can
be used over great
distances; is not
susceptible to EMI;
has a higher data rate
than coaxial and
twisted-pair cable
Difficult to terminate

Single Mode fiber optic cable has
a small diametral core that allows
only one mode of light to
propagate.
NETWORK MEDIA-SINGLE MODE FIBER OPTIC

Because of this, the number of light
reflections created as the light passes
through the core decreases, lowering
attenuation and creating the ability
for the signal to travel faster, further..

Single Mode This application is
typically used in long distance, higher
bandwidth runs by Telcos, CATV
companies, and Colleges and
Universities.

Multimode fiber optic cable has a
large diametral core that allows
multiple modes of light to propagate.
NETWORK MEDIA-MULTI MODE FIBER OPTIC

Because of this, the number of light
reflections created as the light passes
through the core increases, creating
the ability for more data to pass
through at a given time.

Because of the high dispersion and
attenuation rate with this type of
fiber, the quality of the signal is
reduced over long distances. This
application is typically used for short
distance, data and audio/video
applications in LANs.

RF broadband signals, such as what
cable companies commonly use,
cannot be transmitted over
multimode fiber.

Wireless communication uses
radio frequencies (RF) or infrared
(IR) waves to transmit data
between devices on a LAN. For
wireless LANs, a key component is
the wireless hub, or access point,
used for signal distribution
NETWORK MEDIA

NETWORK MEDIA-Wireless LAN
Diagram

NETWORK MEDIA- FREE SPACE OPTIC
FSO is a line-of-sight technology which uses LASERS and
Photo detectors to provide optical connections
between two points—without the fiber.
FSO can transmit data, voice or video at speeds capable
of reaching 2.5 Gbps.

NETWORK MEDIA- FREE SPACE OPTIC
FSO units consist of an optical transceiver with a laser
(transmitter) and a Photo detector (receiver) to provide
full duplex (bi-directional) capability.
FSO systems use invisible infrared laser light
wavelengths.

Requirements of a good Transmission System:
• High Bandwidth
• High BER
• Low SNR
• Power efficient
• Provide Data Security.
• Low cost
• Easy to install and maintain.

A high-bandwidth cost-effective solution to the last mile problem is to use free-space
laser communication (also known as or optical wireless) in a mesh architecture to get
the high bandwidth quickly to the customers.
• NETWORK MEDIA-free space optics

Wi-Fi (or WiFi) is a local area wireless computer
networking technology that allows electronic
devices to connect to the network,
NETWORK MEDIA-wifi

Wi-Fi technology may be used to
provide Internet access to devices that are
within the range of a wireless network that is
connected to the Internet. The coverage of one
or more interconnected access
points (hotspots) can extend from an area as
small as a few rooms to as large as many square
kilometers. Coverage in the larger area may
require a group of access points with
overlapping coverage
NETWORK MEDIA-wifi

Wi-Fi provides service in private
homes, businesses, as well as in
public spaces at Wi-Fi hotspots set
up either free-of-charge or
commercially, often using a
captive portal webpage for access.
NETWORK MEDIA-wifi

Organizations and businesses, such as
airports, hotels, and restaurants,
often provide free-use hotspots to
attract customers. Enthusiasts or
authorities who wish to provide
services or even to promote business
in selected areas sometimes provide
free Wi-Fi access.
NETWORK MEDIA-wifi

Routers that incorporate a DSL-
modem or a cable modem and a Wi-Fi
access point, often set up in homes
and other buildings, provide Internet
access and internetworking to all
devices connected to them, wirelessly
or via cable.
NETWORK MEDIA-wifi

NOISE REDUCTION
Signal Averaging Some noise
reduction techniques prevent the
noise from entering the system
initially, and others remove
extraneous noise from the signal.
Another technique averages several
signal samples through software.
NETWORK MEDIA-NOSE REDUCTION
METHODS

NOISE REDUCTION
Signal Averaging-As such, averaging
suits only low-speed applications, and
it eliminates only random noise. It
does not necessarily eliminate many
other types of annoying system noise,
such as periodic noise from switching
power supplies.
METHODS

NOISE REDUCTION-
Analog Filtering A filter is an analog circuit
element that selectively attenuates a
particular band of frequencies in an
incoming signal. Filter circuits can be
passive or active. Depending on whether
the filter is low or high-pass, it determines
the frequencies that are attenuated above
or below the cutoff frequency.
METHODS

NOISE REDUCTION-
Analog FILTER
METHODS

NOISE REDUCTION-06). Noise
Reduction:
A passive filter is a circuit or device
consisting entirely of non-amplifying
components, typically inductors and
capacitors, which pass one frequency
band while rejecting others.
METHODS

NOISE REDUCTION-06). Noise
Reduction: Passive Filters
METHODS

NOISE REDUCTION-) Noise Reduction:
An active filter, on the other hand, is a
circuit or device composed of
amplifying components such as
operational amplifiers, and suitable
tuning elements, typically resistors
and capacitors, which pass one
frequency band while rejecting others
METHODS

NOISE REDUCTION-) Noise Reduction:
An active filter,
METHODS

SOURCE: CISCO NETWORK MEDIA
HANDOUTS
PUBLISHED
NETWORK MEDIA

networkmedia presentation1

More Related Content

What's hot

Viewers also liked

Similar to networkmedia presentation1

More from uncleRhyme

Recently uploaded

networkmedia presentation1