Brief about networking devices.

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Aim:-Explore and understand the various aspects of networking devices.
1. Networking Cables ( Coaxial, Twisted pair, and Fiber optics )
1.1: - Networking Cables - Coaxial Cable
The signal a coaxial cable carries is transferred simultaneously through the central wire
as well as the separated metal jacketing. This is done because both conductors generate
a magnetic field, as any electrically charged wire does. However, when two opposite
charged magnetic fields, as the ones generated by the two conductors are, come into
contact with one another, the fields cancel one another out. This allows the cables to be
placed near other sensitive electronic equipment and other metal objects without the
danger of the cables acting like magnets. It also prevents outside magnetic fields from
altering the signal the cables carry.
1.2: - Networking Cables - Twisted Pair –
Twisted pair is the ordinary copper wire which connects home and many business
computers to the telephone company. It is made by putting two separate insulated wires
together in a twisted pattern and running them parallel to each other which helps to
reduce crosstalk or electromagnetic induction between pairs of wires.
1. UTP(Unshielded Twisted Pair)
 Ordinary telephone wires
 Less expensive
 Weak immunity against noise & interferences
 Most used in two categories: Cat-3 & Cat-5
 Used in laboratory

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2. STP(Shielded Twisted Pair)
 An extra metallic shield on each pair
 Relatively more expensive
 Better performance than UTP
 Used in exterior network(outside of building).
1.3: - Networking Cables - Fiber Optic Cable
A fiber-optic cable, also known as an optical-fiber cable, is an assembly similar to
an electrical cable, but containing one or more optical fibers that are used to carry light.
The optical fiber elements are typically individually coated with plastic layers and
contained in a protective tube suitable for the environment where the cable will be
deployed. Different types of cable[1] are used for different applications, for example,
long distance telecommunication, or providing a high-speed data connection between
different parts of a building.

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2. Twitter pair cable indetail (Straight through, cross-over, color coding, pin
diagram)
Twisted pair cabling is a type of wiring in which two conductors of a single circuit are
twisted together for the purposes of improving electromagnetic compatibility.
Compared to a single conductor or an untwisted balanced pair, a twisted pair
reduces electromagnetic radiation from the pair and crosstalk between neighboring
pairs and improves rejection of external electromagnetic interference.
2.1:- Straight Through
A straight through cable is a type of twisted pair cable that is used in local area
networks to connect a computer to a network hub such as a router. This type of cable is
also sometimes called a patch cable and is an alternative to wireless connections where
one or more computers access a router through a wireless signal. Straight through cable
use one wiring standard: both ends use T568A wiring standard or both ends use T568B
wiring standard.
2.2:- Crossover Cable
A crossover Ethernet cable is a type of Ethernet cable used to connect computing
devices together directly. Unlike straight through cable, the RJ45 crossover cable uses
two different wiring standards: one end uses the T568A wiring standard, and the other
end uses the T568B wiring standard.

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2.3:- Color Coding - 25 pair
3. Hub:-
A hub is to sent out a message from one port to other ports. For example, if there are
three computers of A, B, C, the message sent by a hub for computer A will also come to
the other computers. But only computer A will respond and the response will also go out
to every other port on the hub. Therefore, all the computers can receive the message and
computers themselves need to decide whether to accept the message.

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4. Switch
A switch is able to handle the data and knows the specific addresses to send the
message. It can decide which computer is the message intended for and send the
message directly to the right computer. The efficiency of switch has been greatly
improved, thus providing a faster network speed.
5. Bridge
A bridge operates at data link layer. A bridge is a repeater, with add on the functionality
of filtering content by reading the MAC addresses of source and destination. It is also
used for interconnecting two LANs working on the same protocol. It has a single input
and single output port, thus making it a 2 port device.
Types of Bridges
 Transparent Bridges:- These are the bridge in which the stations are
completely unaware of the bridge’s existence i.e. whether or not a bridge is
added or deleted from the network, reconfiguration of the stations is
unnecessary. These bridges make use of two processes i.e. bridge forwarding
and bridge learning.
 Source Routing Bridges:- In these bridges, routing operation is performed by
source station and the frame specifies which route to follow. The hot can
discover frame by sending a special frame called discovery frame, which
spreads through the entire network using all possible paths to destination.

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6. Repeater
A repeater operates at the physical layer. Its job is to regenerate the signal over the
same network before the signal becomes too weak or corrupted so as to extend the
length to which the signal can be transmitted over the same network. An important
point to be noted about repeaters is that they do not amplify the signal. When the signal
becomes weak, they copy the signal bit by bit and regenerate it at the original strength.
It is a 2 port device.
7. Router
Router is actually a small computer that can be programmed to handle and route the
network traffic. It usually connects at least two networks together, such as two LANs,
two WANs or a LAN and its ISP network. Routers can calculate the best route for
sending data and communicate with each other by protocols.

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