INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
© 2013, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
INTRODUCTION (1)
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Data Network architecture or Data
Network model is essential to enable
two connected devices to
communicate.
Data Network model is a set of
organised rules of protocols that
facilitate exchange of information
between two connected entities.
© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
INTRODUCTION (2)
Standardisation in the Data Network
architecture is very critical for interoperability.
• Data Network innovation such as
the Internet would not have been
possible without this standard
interoperability.
•In 1977, the ISO and ITU-T started an
effort which produced the Open
Systems Interconnection (OSI)
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© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
BEFORE THE OSI MODEL
Prior to the OSI, there were data
networks models either owned by
governments such as ARPANET (US),
CYCLADES (France) or vendors –
SNA (IBM) and DECnet (DEC).
• ARPANET (US – DoD) is said to be the
“ancestor” of the Internet.
• Both ARPANET and CYCLADES were
packet switching networks.
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© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
THE OSI MODEL
• OSI is a conceptual model
characterised by abstraction layers
representing the internal functions
of a communication system
• OSI – a consistent model of protocol
layers defining interoperability
between network devices and software
• OSI model has seven layers stacked
one over another.
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© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
THE OSI MODEL
• OSI is a conceptual model
characterised by abstraction layers
representing the internal functions
of a communication system
• OSI – a consistent model of protocol
layers defining interoperability
between network devices and software
• OSI model has seven layers stacked
one over another.
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© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
THE OSI MODEL
OSI MODEL
APPLICATION LAYER (7)
PRESENTATION LAYER (6)
SESSION LAYER (5)
TRANSPORT LAYER (4)
NETWORK LAYER (3)
DATA LINK LAYER (2)
PHYSICAL LAYER (1)
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© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
THE OSI MODEL
OSI MODEL
LAYER
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FUNCTION
7. APPLICATION
Network process to application
6. PRESENTATION
Data representation, encryption and decryption,
convert machine dependent data to machine
independent data
5. SESSION
Interhost communication, managing sessions
between applications
4. TRANSPORT
End-to-end connections, reliability and flow control
3. NETWORK
Path determination and logical addressing
2. DATA LINK
Physical addressing
1. PHYSICAL
Media, signal and binary transmission
© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
THE TCP/IP
• The Internet protocol suite is the
networking model and a set of
communications protocols used for
the Internet and similar networks
• It is commonly known as TCP/IP
because Transmission Control Protocol
(TCP) and Internet Protocol (IP)
were the first networking protocols
to be developed in this standard.
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© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
THE TCP/IP
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The TCP/IP was heavily influenced
by the US-DoD’s ARPANET
TCP/IP provides end-to-end
connectivity specifying how data
should be formatted, addressed,
transmitted, routed and received
at the destination.
© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
THE TCP/IP
•Beware – TCP/IP is known as a 5layers stack in mainstream literature;
(4--layers in other literature)
• TCP/IP is the most widely used
network architecture; it has been
the industry standard
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© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
TCP/IP STACK
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© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
THE TCP/IP STACK
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© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
OTHER DATA NETOWRKS (1)
• GSM (Global System for Mobile
Communication, initially it stood for
‘Groupe Special Mobile’) – 1GN
• GSM – 2GN
• GPRS (General Packet Radio
Service) and EDGE (Enhanced Data
rates for GSM Evolution) – 2.5GN;
data speed: 800Mhz in Europe, about
1.9Ghz in US.
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© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
OTHER DATA NETOWRKS (2)
• UMTS (Universal Mobile
Telecommunications System)
and CDMA (Code Division Multiple
Access) – 3GN, 3.5GN and 4GN; data
speed: 1.8 – 2 Ghz
• They are all using customised variations
of the OSI model.
• This has enabled Mobile data where your
phone goes online away from Wi-Fi.
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© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
OTHER DATA NETOWRKS (2)
• Mobile-enabled devices can send
and and receive information over
a wireless cellular connection.
• As long as you have a cellular
connection, you can use the
Internet.
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© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering
INTRODUCTION TO INFORMATION & COMMUNICATION TECHNOLOGY (ICT)
OTHER DATA NETOWRKS (3)
• Mobile-enabled devices can
send
send
and receive information over a
wireless cellular connection.
• As long as you have a cellular
connection, you can use the
Internet.
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© 2019 - 2024, University of Zambia, Department of Electrical & Electronic Engineering