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Computer Networks -Introduction
Presentation by
A.Jawahar
SSN College of Engineering
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Objective
At the end of this section students will be
able to understand The concept of Data Communication
Networking Protocols and Standards
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Data Communication
Exchange of data between two devices via
some form of transmission medium Effectiveness of data communication
depends on Delivery Accuracy
Timeliness Jitter
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Components of Data Communication Message
Sender Receiver
Transmission medium Protocol
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Components of Data Communication
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Data Representation
Text
Numbers
Images
Audio Video
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Data flow Simplex
Half Duplex Full Duplex
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Data flow - Simplex
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Data flow Half duplex
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Data flow Full Duplex
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Networks A network is a set of devices (called nodes)
connected by communication links. A node maybe a computer, printer or any other devicecapable of sending and/or receiving datagenerated by other nodes in the network.
Distributed Processing
Network Criteria
Physical Structures
Categories of Networks
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Distributed Processing Most networks use distributed processing,
in which a task is divided among multiplecomputers.
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Network Criteria Performance
Reliability Security
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Physical Structures
Type of connection Point to Point Multipoint
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Point to Point
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Multipoint
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Physical Topology
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Physical Topology - Mesh
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Physical Topology - Star
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Physical Topology - Bus
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Physical Topology - Ring
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Network Models OSI model seven layered
Internet model five layered
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Categories of Networks
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LAN
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LAN
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MAN
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WAN
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Protocols and StandardsProtocols
Standards
Standards Organizations
Internet Standards
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Protocols Syntax
Semantics Timing
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Standards De facto by fact
De jure by law
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Standard Organizations ISO
ITU-T CCITT
ANSI EIA
Forums Regulatory Agencies - FCC
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Internet Standards An internet standard is a thoroughly
tested specification that is useful to andadhered to by those who work with theinternet.
Internet draft
Request for comment (RFC)
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Summary Data communications are the transfer of
data from one device to another via someform of transmission medium.
Accurate and timely transmission.
Components message, sender, receiver,medium, protocol
Data forms image, text, audio, video
Data flow simplex, half duplex, fullduplex
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Summary A network is a set of communication
devices connected by media links.
Topology mesh, star, bus, ring
Network categories LAN, MAN, WAN
An internet is a network of networks. An internet is a collection of many
separate networks
There are logical, regional, national andinternational Internet Service Providers.
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Summary Protocol set of rules that govern data
communication
Standards ensure that products fromdifferent manufacturers can work together
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Review Questions In a _______ connection, more than two devices can
share a single link.
A) Point-to-point B) Primary C) Multipoint D)
Secondary Communication between a computer and a keyboardinvolves ______________ transmission.
A) Full-duplex B) Half-duplex C) Simplex D)
Automatic The information to be communicated in a data
communications system is the _______.
A) Medium B) Protocol C) Transmission D) Message
Frequency of failure and network recovery time after afailure are measures of the _______ of a network.
A) Performance B) Security C) Reliability D) Feasibility
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Review Questions In a network with 25 computers, which topology would
require the most extensive cabling?
A) Star B) Mesh C) Bus D) Ring Which topology requires a central controller or hub? A)
Star B) Mesh C) Bus D) Ring
The _______ is the physical path over which a messagetravels.
A) Protocol B) Medium C) Signal D) All the above
Which organization has authority over interstate andinternational commerce in the communications field?A) ITU-T B) IEEE C) ISO D) FCC
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Review Questions In _______ transmission, the channel capacity is shared
by both communicating devices at all times.A) Full-duplex B) Simplex C) Half-duplex D) Half-simplex
An unauthorized user is a network _______ issue.A) Performance B) Reliability C) Security D) All theabove
Which topology requires a multipoint connection?A) Mesh B) Star C) Ring D) Bus
A television broadcast is an example of _______
transmission.A) Half-duplex B) Full-duplex C) Simplex D)Automatic
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Review Questions A _______ connection provides a dedicated link between
two devices.
A) Multipoint B) Point-to-point C) Primary D)Secondary
A cable break in a _______ topology stops all
transmission.A) Mesh B) Star C) Primary D) Bus