Networking: Computer Networks and Protocols

Networking
Computer network A collection of
computing devices that are connected in
various ways in order to communicate and
share resources
Usually, the connections between computers
in a network are made using physical wires or
cables
However, some connections are wireless,
using radio waves or infrared signals
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Networking
The generic term node or host refers to any
device on a network
Data transfer rate The speed with which
data is moved from one place on a network to
another
Data transfer rate is a key issue in computer
networks
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NetworkingComputer networks have opened up an entire
frontier in the world of computing called the
client/server model
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Figure 15.1 Client/Server interaction

Networking
File server A computer that stores and
manages files for multiple users on a network
Web server A computer dedicated to
responding to requests (from the browser
client) for web pages
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Types of Networks
Local-area network (LAN) A network that
connects a relatively small number of
machines in a relatively close geographical
area
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Types of Networks
Various configurations, called topologies,
have been used to administer LANs
Ring topology A configuration that connects all
nodes in a closed loop on which messages travel in
one direction
Star topology A configuration that centers
around one node to which all others are connected
and through which all messages are sent
Bus topology All nodes are connected to a
single communication line that carries messages
in both directions
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Types of Networks
A bus technology called Ethernet has become
the industry standard for local-area networks
Figure 15.2 Various network topologies
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Types of Networks
Wide-area network (WAN) A network that
connects two or more local-area networks
over a potentially large geographic distance
Often one particular node on a LAN is set up to
serve as a gateway to handle all communication
going between that LAN and other networks
Communication between networks is called
internetworking
The Internet, as we know it today, is essentially
the ultimate wide-area network, spanning the
entire globe
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