Introduction
Data communication is the transfer of data from one device to another via some form of transmission medium.
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A
data communications system must transmit data to the correct destination in an
accurate and timely manner.
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The
five components that make up a data communications system are the message,
sender, receiver, medium, and protocol.
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Text,
numbers, images, audio, and video are different forms of information.
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Data
flow between two devices can occur in one of three ways: simplex, half-duplex,
or full-duplex.
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A
network is a set of communication devices connected by media links.
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In
a point-to-point connection, two and only two devices are connected by a
dedicated link. In a multipoint connection, three or more devices share a link.
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Topology
refers to the physical or logical arrangement of a network. Devices may be
arranged in a mesh, star, bus, or ring topology.
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A
network can be categorized as a local area network (LAN), a metropolitan-area
network (MAN), or a wide area network (WAN).
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A
LAN is a data communication system within a building, plant, or campus, or
between nearby buildings.
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A
MAN is a data communication system covering an area the size of a town or city.
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A
WAN is a data communication system spanning states, countries, or the whole
world.
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An
internet is a network of networks.
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The
Internet is a collection of many separate networks.
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TCP/IP
is the protocol suite for the Internet.
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There
are local, regional, national, and international Internet service providers
(ISPs).
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A
protocol is a set of rules that governs data communication; the key elements of
a protocol are syntax, semantics, and timing.
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Standards
are necessary to ensure that products from different manufacturers can work
together as expected.
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The
ISO, ITU-T, ANSI, IEEE, and EIA are some of the organizations involved in
standards creation.
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Forums
are special-interest groups that quickly evaluate and standardize new
technologies.
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A
Request for Comment (RFC) is an idea or concept that is a precursor to an
Internet standard.
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