Transcript computer networking - BSNL Durg SSA(Connecting India)

COMPUTER NETWORKING
A computer network, often simply referred to as a
network, is a collection of computers and devices
interconnected by communications channels that facilitate
communications and allows sharing of resources and
information among interconnected devices.[1] Put more
simply, a computer network is a collection of two or more
computers linked together for the purposes of sharing
information
PROJECT-ON
SETTING FOR NETWORKING OF FIFTY PC
Advantages of Computer Networks
File Sharing
Resource Sharing
Increased Storage Capacity
Increased Cost Efficiency
Disadvantages of Computer Networks
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Security Issues
Rapid Spread of Computer Viruses
Expensive Set Up
Dependency on the Main File Server:
TYPES OF NETWORK
• Peer-to-Peer Networking
This is a simple network configuration that requires some basic
know-how to set up. Each of the interconnected machines share dual
capability and responsibility on the network. That is to say, that each
machine serves a dual purpose or role, i.e. they are both clients and
servers to some extent.
• Client/Server Networks
Server based networks, or client/server networks as they are
properly called, has a machine at the heart of its operations called
the server. A server is a machine that provides services over a
network by responding to client requests. Servers rarely have
individuals operating it, and even then, it is usually to install,
configure or manage its capabilities. The server's essential role on
the network is to be continuously available to handle the many
requests generated by its clients.
OTHER TYPES OF NETWORK
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LOCAL AREA NETWORK
METROPOLITEN AREA NETWORK
WIDE AREA NETWORK
CAMPUS AREA NETWORK
SYSTEM AREA NETWORK
DEVICES OF COMPUTER NETWORKING
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Common basic networking devices:
Router: a specialized network device that determines the next network point to
which it can forward a data packet towards the destination of the packet. Unlike a
gateway, it cannot interface different protocols. Works on OSI layer 3.
Bridge: a device that connects multiple network segments along the data link layer.
Works on OSI layer 2.
Switch: a device that allocates traffic from one network segment to certain lines
(intended destination(s)) which connect the segment to another network
segment. So unlike a hub a switch splits the network traffic and sends it to
different destinations rather than to all systems on the network. Works on OSI
layer 2.
Hub: connects multiple Ethernet segments together making them act as a single
segment. When using a hub, every attached all the objects, compared to switches,
which provide a dedicated connection between individual nodes. Works on OSI
layer 1.
Repeater: device to amplify or regenerate digital signals received while sending
them from one part of a network into another. Works on OSI layer 1
Other hardware for establishing
networks or dial-up connections
• Multiplexer: device that combines several electrical signals
into a single signal
• Network Card: a piece of computer hardware to allow the
attached computer to communicate by network
• Modem: device that modulates an analog "carrier" signal
(such as sound), to encode digital information, and that
also demodulates such a carrier signal to decode the
transmitted information, as a computer communicating
with another computer over the telephone network
• ISDN terminal adapter (TA): a specialized gateway for ISDN
• Line Driver: a device to increase transmission distance by
amplifying the signal. Base-band networks only
CABLES USE FOR NETWORKING
• Networking Cables are used to connect one network
device to other or to connect two or more computers
to share printer, scanner etc. Different types of
network cables like Coaxial cable, Optical fiber cable,
Twisted Pair cables are used depending on the
network's topology, protocol and size. The devices can
be separated by a few meters (e.g. via Ethernet) or
nearly unlimited distances (e.g. via the
interconnections of the Internet).
• While wireless may be the wave of the future, most
computer networks today still utilize cables to transfer
signals from one point to another.[1]
THERE ARE THREE TYPES
• Twisted pair
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Twisted pair cabling is a form of wiring in which two
conductors (the forward and return conductors of a single circuit) are
twisted together for the purposes of canceling out electromagnetic
interference (EMI) from external sources; for instance, electromagnetic
radiation Twisted pair are classified into two types unshielded twisted pair
shielded twisted pair from unshielded twisted pair (UTP) cables, and
crosstalk between neighboring pairs.This type of cable is used for home
and corporate networks utilising the RJ45 connector ends
• Optical fiber cable
An optical fiber cable is a cable containing one or more
optical fibers. 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.
Coaxial cable
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Coaxial cabling has a single copper conductor at its center. A plastic layer provides
insulation between the center conductor and a braided metal shield (See fig. 3).
The metal shield helps to block any outside interference from
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Although coaxial cabling is difficult to install, it is highly resistant to signal
interference. In addition, it can support greater cable lengths between network
devices than twisted pair cable. The two types of coaxial
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Thin coaxial cable is also referred to as thinnet. 10Base2 refers to the specifications
for thin coaxial cable carrying Ethernet signals. The 2 refers to the approximate
maximum segment length being 200 meters. In actual fact the maximum segment
length is 185 meters. Thin coaxial cable has been popular in
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Thick coaxial cable is also referred to as thicknet. 10Base5 refers to the
specifications for thick coaxial cable carrying Ethernet signals. The 5 refers to the
maximum segment length being 500 meters. Thick coaxial cable has an extra
protective plastic cover that helps keep moisture away from the center conductor.
This makes thick coaxial a great choice when running longer lengths in a linear bus
network. One disadvantage of thick coaxial is that it does