network communication media and devices

1. Network Communication Media
and Devices

2. Introduction
• In computer networks, devices/nodes pass
data to each other along data connections.
The connections or network links between
devices/nodes are established using
either cable media or wireless media.
• Network media: is the physical or wireless
channel used for transmission in the network.
Wire/cables, and wireless/air are the two
main types of media.

3. Types of Wired/Cable Media
• There are three types of cables used: these
are:
– Twisted pair
– Coaxial cable,
– Fiber optic.

4. Twisted Pair
• Twisted pair cabling is a type of wiring in
which two conductors of a single circuit
are twisted together for the purposes of
canceling out electromagnetic interference
from external sources. There are two types of
twisted pair

5. Twisted Pair Cables
• Shielded Twisted Pair
– It uses metallic shield wrapping to protect the wire
from interference
• Unshielded Twisted Pair (UTP)
– This is the most popular form of cables in the network
and the cheapest form that you can go with. The UTP
has four pairs of wires and all are inside plastic
sheathing. The biggest reason that we call it Twisted
Pair is to protect the wires from interference from
themselves. Each wire is only protected with a thin
plastic sheath.

7. Coaxial Cable
• Coaxial cables are a type of cable that is used
by cable TV (e.g. DSTV)and that is also commonly
used for data communications. Its made up of a
single center solid wire symmetrically surrounded
by a braided or foil conductor. Between the
center wire and foil is a insulating dielectrics.
• Coaxial cable is sometimes used by telephone
companies from their central office to the
telephone poles near users. It is also widely
installed for use in business, Ethernet and other
types of local area network.

9. Fiber Optic Cable
• Its a technology that uses glass (or plastic)
threads (fibers) to transmit data. A fiber optic
cable consists of a bundle of glass threads,
each of which is capable of transmitting
messages modulated onto light waves.

10. Advantages/Disadvantages of Fiber
Optics
• Advantages
– Fiber optic cables have a much greater bandwidth than
metal cables. This means that they can carry more data.
– Fiber optic cables are less susceptible than metal cables to
interference.
– Fiber optic cables are much thinner and lighter than metal
wires.
– Data can be transmitted digitally (the natural form
for computer data) rather than analogically.
• Disadvantages
– Expensive
– Difficult to install. In addition, they are more fragile than
wire and are difficult to splice (join or merged together).

11. Fiber Optic Cable

12. Cables Standards and Connectors
• Something else to note about cables is that they are
defined in numbers also. The bigger the number the
better the protection from interference. Most
networks should go with no less than a CAT 5 or CAT6
or 6a (Augmented Cat 6) is most recommended.
• Now you know about cables we need to know about
connectors. This is pretty important and you will most
likely need the RJ-45 connector. This is the cousin of
the phone jack connector and looks real similar with
the exception that the RJ-45 is bigger.

13. Connectors

14. Fiber Optic Connectors

15. SAT3 Project
• SAT-3/WASC or South Atlantic 3/West Africa Submarine
Cable is a submarine communications
cable linking Portugal and Spain to South Africa, with
connections to several West African countries along the
route.
• It forms part of the SAT-3/WASC/SAFE cable system, where
the South Africa Far East (SAFE) cable links South Africa
to Asia. The SAT-3/WASC/SAFE system provides a path
between Asia and Europe for telecommunications traffic.
• The South Africa Far East cable is an optical
fiber submarine communications cable linking South Africa
and, Malaysia.

16. SAT-3/WASC/SAFE

17. Marine Fiber Optic Installation

18. Wireless/Air Media
• Wireless transmission media send
communications signals by using
– broadcast radio,
– cellular radio,
– microwaves,
– satellites,
– infrared signals.

19. Radio Waves
• Radio waves is a wireless transmission
medium that distributes radio signals through the
air. Radio waves are widely used as signals on
radio communication
• A transmitter is needed to send the broadcast
signal and a receiver is needed to accept the
signal.
• Some networks use a transceiver, which both
sends and receives signals from wireless devices.

20. Radio Waves

21. Microwaves
• Microwaves are radio waves that provide a
high-speed signal transmission. Microwaves
transmission involves sending signals from
one microwave station to another.
• Microwaves transmission is fast but is limited
to line-of-sight transmission, which means
that the microwaves must transmit in a
straight line with no obstructions between
microwave antennas.

22. Microwaves
• Microwaves stations are often located on the
tops of buildings, towers, or mountains to avoid
possible obstructions. Microwaves transmission is
used where installing physical transmission
media is difficult or impossible (e.g., deserts,
lakes), but where line-of-sight transmission is
available.
• Radio waves in general have long distance
communication capabilities, than microwaves..

23. Microwaves

24. Microwave Backup

25. Cellular Radio
• Cellular radio is a form of broadcast radio that is used
widely for mobile communications, specifically cellular
telephones.
• Its used over land areas called cells, with each served
by at least one fixed location transceiver, known as
a Cell Site or Base Station.
• When joined together these cells provide radio
coverage over a wide geographic area. This enables a
large number of portable transceivers (e.g., mobile
phones, pagers, etc.) to communicate with each other
and with fixed transceivers and telephones anywhere
in the network, via base stations

26. Cellular Radio

27. Satellite Communication
• A communications satellite is a station in space that
receives microwaves signals from an earth-based
station, amplifies the signals, and broadcasts the
signals back over a wide area to many earth-based
stations.
• Communications satellites are usually placed about
22,300 miles above the Earth's equator and moves at
the same rate as the Earth.
• Applications of communications satellite include
television and radio broadcasts, videoconferencing,
paging, and global positioning systems(GPS).

28. Satellite

29. Infrared
• Infrared (IR) is a wireless transmission media that
sends signals using infrared light waves.
• IR transmission also requires a line-of-sight
transmission as that required by microwaves.
• Computer devices such as a mouse, printer,
and digital camera, which have an IrDA port may
transfer data from one device to another using
infrared light waves.
• IR is an alternative to short-range broadcast
radio communications such as Bluetooth.

30. Bluetooth
• Bluetooth is a kind of short-range (about 10
meters) broadcast radio communications,
which can transmit data at a rate of 1 Mbps
among Bluetooth-enabled devices.
• Examples of Bluetooth devices include
desktop computers, notebook computers,
handheld computers, Internet appliances,
cellular telephones, and printers.

31. Network Devices
• Repeaters
– A hardware device that amplifies a signal that has traveled
a long distance.
• Switches
– It’s a small hardware device that joins multiple computers
together within one local area network. Switches have the
ability to selectively forward data packets to a specific
destination.
• Bridges
– A hardware device that connect two networks and breaks
the segments of one network into smaller groups. Bridges
filter incoming traffic and decide whether to forward or
discard it.

32. Network Devices
• Routers
– A network device that determines where information packets
should go and sends them to their destination by the shortest,
most efficient route.
• Network Interface Cards
– A computer circuit board or card that is installed in a computer
so that it can be connected to a network. Network interface
cards provide a dedicated, full-time connection to the network.
• Patch Panel
– A patch panel is a mounted hardware unit containing an
assembly of port locations in a communications or other
electronic or electrical system. It serves as a sort of static
switchboard, using cables to interconnect computers within the
area of a local area network

33. END OF LECTURE