Docstoc

Computer networks

Document Sample
Computer networks Powered By Docstoc
					                          Computer networks

The term 'network' defines a set of entities (objects, people, etc.) interconnected with
each other. A network allows to circulate material elements or intangible between
each of these entities according to well defined rules. computer network: set of
Computers connected to each other through physical lines and exchanging
information in the form of digital data.


A computer is a machine for manipulating data. Man, as a being calling, quickly
understood the interest there could be to link these computers between - them in order
to be able to exchange of information. A computer network can serve several
purposes:
      Sharing of resources (files, applications, or hardware, internet connection,
       etc.)
      Communication between people (email, discussion online, etc.)
      Interprocess communication (between industrial computers for example)
      The guarantee of the uniqueness and universality of access to information
       (network database)
      The multiplayer video game


The different types of networks usually have the following in common:
      Servers: computers that provide shared users by a network server resources
      Customers: computers accessing shared resources provided by a network
       server
      Support of connection: determines how computers are interconnected.
      Shared data: files accessible on the network servers
      Shared printers and other devices: files, printers, or other items used by the
       users of the network
      Various resources: other resources provided by the server




There are different types of networks depending on their size (in terms of number of
machines), their speed transfer of data as well as their extent. There are generally
three categories of networks:
      LAN (local area network)
      MAN (metropolitan area network)
      WAN (wide area network)


The LAN
The term 'network' defines a set of entities (objects, people, etc.) interconnected with
each other. A network allows to circulate material elements or intangible between
each of these entities according to well defined rules.
-> computer network: set of computers connected to each other through physical lines
and exchanging information in the form of digital data.Computer networks: definition
A computer is a machine for manipulating data. Man, as a being calling, quickly
understood the interest there could be to link these computers between - them in order
to be able to exchange of information.


A computer network can serve several purposes:
      Sharing of resources (files, applications, or hardware, internet connection,
       etc.)
      Communication between people (email, discussion online, etc.)
      Interprocess communication (between industrial computers for example)
      The guarantee of the uniqueness and universality of access to information
       (network database)
      The multiplayer video game


The different types of networks usually have the following in common:
      Servers: computers that provide shared users by a network server resources
      Customers: computers accessing shared resources provided by a network
       server
      Support of connection: determines how computers are interconnected.
      Shared data: files accessible on the network servers
      Shared printers and other devices: files, printers, or other items used by the
       users of the network
      Various resources: other resources provided by the server


Similarities between types of networks
There are different types of networks depending on their size (in terms of number of
machines), their speed transfer of data as well as their extent. There are generally
three categories of networks:
      LAN (local area network)
      MAN (metropolitan area network)
      WAN (wide area network)


The different types of networks
LAN means Local Area Network (in French Local network). This is a set of
computers belonging to same organization and linked together in a small
geographical area by a network, often using a same technology (the most common
being Ethernet). A local area network is therefore a network in its simplest form. The
speed of transfer of data from a local network may range between 10 Mbps (for an
Ethernet for example) and 1 Gbps (Gigabit Ethernet or FDDI by) (example). The size
of a local network can reach up to 100 or even 1000 users. By expanding the context
of the definition in services bring the local network, it is possible to distinguish two
modes of operation:
       in an environment of "peer to peer" (Eng., peer to peer), in which there is no
        central computer and each computer has a similar role
       in a "client/server environment, in which a central computer provides network
        services to the users.


The MAN
The MAN (Metropolitan Area Network) interconnect several LAN geographically
lose (maximum) (a few tens of km) at high flow rates. Thus a MAN allows two
remote nodes to communicate as if they were part of a local network. A MAN
consists of switches or routers interconnected by links high speeds (usually
fiberglass) (optical).


THE WAN
A WAN (Wide Area Network or WAN) interconnects multiple LANs across great
distances geographical. Available on a WAN flows are the result of an arbitration
with the cost of the bonds (which increases with the distance) and may be low. The
WAN work through routers that allow to "choose" the path most appropriate to
achieve a the network node. The best known of the WAN is the Internet

				
DOCUMENT INFO
Shared By:
Stats:
views:24
posted:10/7/2012
language:English
pages:4
Description: Computer networks