Things you need to know …
Data Communication &
Networking
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Instructor:
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Office:
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Introduction
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Data Communications and Networking
Communications - Behrouz A. Forouzan
Data and Computer Communications -
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Computer Networks - Andrew S. Tanenbaum
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Data Communication
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Communication at a distance, includes telephony,
telegraphy, television etc.
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Message, Sender, Receiver, Medium, Protocol
Transfer of data from one or more sources to one or more
destinations.
A set of rules that
governs data
communication
A network of data processing nodes that are
interconnected for the purpose of data communication.
The data
(information) to be
communicated
Node
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Telecommunication
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Computer Network
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Information transfer, according to agreed conventions
using hand signals, language, Morse code, smoke signals
etc.
Components of data
communication system
What is … ?
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refers to information presented in whatever form is agreed
upon by the parties creating and using the data.
Communication
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Reference Book:
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Data
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William Stallings
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Take appointment before meeting,
preferably via email
What is … ?
Text Books:
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mnaseem105@gmail.com
Student Consultation:
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Things you need to know …
2nd Floor, Block-B
Email:
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Dr. Rehan Qureshi / Muhammad Naseem
A node can be a computer or printer etc. or any other
device capable of sending and/or receiving data.
The physical
path by which a
message travels
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Effectiveness of Data
Communication System
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Data representation
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Depends on few characteristics, such
as …
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To deliver data to correct destination
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To deliver data accurately (unaltered)
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Timeliness
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To deliver data in a timely manner
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Direction of data flow
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Simplex
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Half-duplex
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Networks
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A network is a set of devices (nodes)
connected by communication links.
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Because of networks we can …
Full-duplex
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Types of Connection
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Share resources ( Peripherals, files,
internet connection etc.)
Communicate and collaborate
Save data
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Point-to-point connection
A link is a communications pathway
that transfers data from one device to
another
Point-to-point
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American Standard Code for Information Interchange
Extended ASCII
Unicode
Numbers
Images
Audio
Video
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ASCII
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Accuracy
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Delivery
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Text
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Multipoint
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Provides a dedicated link between devices.
Entire capacity of the link is reserved for the
two devices.
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Multipoint connection
Network Topology
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More than two specific devices share a
single link.
The capacity of the channel is shared.
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Mesh topology
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Bus topology
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Star topology
Every device has a
dedicated point-to-point
link to every other
device.
A fully connected mesh
network has n(n-1)/2
physical (duplex)
channels to connect n
devices with each device
having n-1 I/O ports.
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It refers to the way in which a network is laid
out physically.
It is a geometric representation of the
relationship of all the links and linking
devices to one another.
Each device has a dedicated point-to-point
link to a central controller (usually a hub).
Less expensive than mesh.
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Ring topology
One long cable acts as a backbone to link
all devices.
Multipoint connection (shared link)
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Each device has a dedicated point-to-point
connection only with two other devices.
A signal is passed along the ring in one
direction.
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Hybrid topology
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Categories of networks
A network can have hybrid or a combination
of different topologies
Example: a star backbone with three bus
networks
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Local Area Network (LAN)
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LAN
Usually owned by same organization
as attached devices
Data rates much higher
Usually broadcast systems
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Metropolitan Area Network
(MAN)
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Building or small campus
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A Network is categorized with respect to its
size, its ownership, the distance it covers
and its physical architecture.
Smaller scope
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Wide Area Network (WAN)
Middle ground between LAN and WAN
May be owned by Private company or a service
provided by a public company
It normally covers the area inside a town or a city
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Provides long-distance communication over
large geographic areas that may comprise a
large region, a country, a continent, or even
the whole world.
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Interconnection of Networks:
Internetwork
Wide Area Network (WAN)
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When two or more
networks are connected,
they become an
internetwork, or internet.
Can be as complex as the backbones that connect
the Internet (switched WAN)
Can be as simple as a dial-up line that connects a
home computer to the Internet (point-to-point WAN)
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The Internet
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Protocol
The Internet is a global system of
interconnected computer networks.
It is a network of networks that
consists of millions networks, linked by
a broad array of electronic, wireless,
and optical networking technologies.
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A protocol is a set of rules that govern data
communications.
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A protocol defines …
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Standards Organizations
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Standards provide guidelines to
manufacturers, vendors, government
agencies, and other service providers
to ensure the kind of interconnectivity
necessary in today's marketplace and
in international communications.
Standards are developed through the
cooperation of standards creation committees,
forums, and government regulatory agencies,
such as …
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what is communicated
how it is communicated
when it is communicated
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Standards
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International Organization for Standardization (ISO)
International Telecommunication UnionTelecommunication Standards Sector (ITU-T)
American National Standards Institute (ANSI)
Institute of Electrical and Electronics Engineers (IEEE)
European Telecommunications Standards Institute
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(ETSI)
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Internet Standards
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An Internet Standard is a specification of a technology
or methodology applicable to the Internet.
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specified as one or more Request for Comments (RFC)
document(s)
published by the Internet Engineering Task Force (IETF)
Contributions to the IETF start as an Internet Draft.
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This is a working document (a work in progress) with no
official status and limited lifetime
Upon recommendation from the Internet authorities, a
draft may be promoted to RFC.
 RFCs may be labeled as Proposed Standards, Draft
Standards or Internet Standards depending on their
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Summary
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Data communication and networking
basic terminology
Types of connections
Network topology
Categories of networks
Protocols and Standards
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