Communication and Networks Assignment
Communications and Networks
version 1.0
Diploma in Information Technology
Copyright © 2020 by Singapore Institute of Management Pte Ltd. All rights reserved.
Lesson 1: Overview of Communication and Networking
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Lesson 1 Learning Outcomes
Understand the evolution of computer networking
Identify the five key aspects of networking
Define the term data communications
Define interoperability and communication protocol
Describe how packet switching and the Internet revolutionise data communication and computer networking
Compare and contrast the OSI and TCP/IP model
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Lesson 1 Outline
Evolution of Computer Networking
Key Aspects of Networking
Interoperability and Standards
OSI and TCP/IP Model
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Network & Internet
Network: system for connecting computer using a single transmission technology
Internet: set of networks connected by routers that are configured to pass traffic among any computers attached to networks in the set
Source: Bing images licensed under CC BY-NC-ND
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Evolution of Internet (1/2)
Roots in military network called ARPANET
Fundamental changes from centralized to distributed computing
Incorporated reliability and robustness
Multiple links & distributed routing
Source: Bing images licensed under CC BY-SA
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Evolution of Internet (2/2)
Ethernet standard made local networking feasible
TCP/IP protocol made internetworking possible
Developed after Arpanet
Switchover occurred in 1983
Exponential growth
doubling every 18 months
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History of Internet
Source: https:// www.youtube.com / watch?v =h8K49dD52WA
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Growth of Computer Networks
Computer networks (NW) growing explosively
used in advertising, production, shipping, planning, billing, and accounting
Continued growth of the global Internet is one of the most exciting phenomena in NW
Source: Bing images licensed under CC BY-SA
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Economic Impact
Data NW made telecommuting available to individuals and have changed business communication
Popularity & importance of NW has produced a demand in all industries for people with more NW expertise
Companies need workers to plan, acquire, install, operate, and manage the hardware (HW) and software (SW) systems that comprise computer NW and Internets
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Why Network is Complex
Diverse technologies, each has features that distinguish it from the others
Multiple NW standards, some are incompatible
Various commercial NW products and services that use the technologies in unconventional ways
Multiple technologies required to interconnect two or more NW
Many combinations of NW are possible!
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Challenges for Beginners
No simple and uniform terminology for NW concepts
Multiple terms exist for a given concept
Large set of terms & acronyms that contains many synonyms
NW jargon contains terms that are often abbreviated, misused, or associated with products
Source: Bing images licensed under CC BY-SA
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Network Conceptual Models
Various conceptual models to be used to explain the differences and similarities among NW HW and SW systems
Simplistic models: do not distinguish among details
Complex models: do not help simplify the subject
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Simplistic Models
Complex Models
Practice 1.1
Define network and Internet. How are networks and the Internet related?
Describe 4 reasons why network is complex.
B
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Lesson 1 Outline
Evolution of Computer Networking
Key Aspects of Networking
Interoperability and Standards
OSI and TCP/IP Model
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Five Key Aspects of Networks
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1. Network Applications
2. Data Communications
3. Packet Switching
4. Internetworking with TCP/IP
5. Public and Private Networks
1. NW Applications & Programming
Network applications: program that communicates across a network
Email, file transfer, web browsing
Network programming: write codes for network applications to communicate across a network
Similar to conventional programming
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2. Data Communication
Data communication: study of low-level technologies used to send information across a medium like wire and radio wave
Provides foundation of concepts on which networking is built upon
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3. Packet Switching
Packet switching: a way to allow multiple senders to transmit data over a shared network
Divides data into small blocks call packets
Each packets has an identification for the intended recipient
Source: Bing images licensed under CC BY-SA
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4. Internetworking with TCP/IP
Transmission Control Protocol (TCP)
Transport layer protocol that receives data and divide them into smaller packets
Internet Protocol (IP)
Network layer protocol that deals with the routing of the packets through the Internet
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5. Public & Private Networks
Internet Service Providers (ISP): are vendors who offer Internet access for a fee
Public network: a network owned by a ISP and offers service to any individual or organisation that pays the subscription fee
Private network: a network that is restricted to one group
Can be leased from a provider
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Private Network Types
Consumer: smallest and least expensive network
Small Office/Home office (SOHO): slightly larger than consumer network
Small-to-medium Business (SMB): larger than SOHO, usually multiple offices in a building
Large Enterprise: large network with multiple buildings
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Practice 1.2
What is data communication?
Describe how does packet switching works
B
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Lesson 1 Outline
Evolution of Computer Networking
Key Aspects of Networking
Interoperability and Standards
OSI and TCP/IP Model
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History of Communication
Source: https:// www.youtube.com / watch?v =0ay2Qy3wBe8
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Communications
Communication must involved at least two entities
One to sends the information
One to receive it
Can also contain intermediate entities
Devices to forward packets
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Interoperability
Misunderstanding can occur in communications
Real-world: different language, different context etc.
Network: disruptions, corrupted data, congestion
Interoperability: ability of two entities to communicate without misunderstanding
Source: Bing images licensed under CC BY-SA-NC
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Interoperability for Communication
Communication between entities must agree on the details
Electrical voltage used to the format and meaning of messages
To ensure entities can interoperate, rules for all aspects of communications are written down
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Communication Protocol
Protocols are specification or set of rules
Communication protocol: specifies details for one aspect of computer communication
Actions taken when errors arises
Voltage and signals to be used
Format of messages that applications exchange
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Networking Standards
Networking standards ensure interoperability between product vendors
de jure: if they have been produced or accepted by a recognized standards body
de facto: if they have not been accepted by a recognized body but have gained widespread use by market forces
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de jure Standards
Hardware and communications standards are often de jure
Network routers
Software standards are often de facto
Microsoft Windows
Competitive markets will arise after de jure standards have been agreed and stabilized
Achieved by having different vendors work together in standard bodies to agree standards for new technologies
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de facto Standards
Can be divided into two kinds
Proprietary standards which are produced, owned and controlled by a commercial organization
Microsoft Windows
Open standards may originally produced by a commercial organization but since transferred to the public domain
Unix
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Practice 1.3
What is interoperability?
Distinguish between the two main types of standards.
B
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Lesson 1 Outline
Evolution of Computer Networking
Key Aspects of Networking
Interoperability and Standards
OSI and TCP/IP Model
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Network Architecture
Engineers like to define an architecture for complex system
Easier to design, build, test and maintain
Network architecture
Structured framework within which networks can be analysed, designed and implemented, incorporating a defined set of layers and protocols
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Cooperating Protocols
Protocol suite: set of protocols that work together to fulfil a communication
Each protocol fulfil one aspect
Abstract version of protocol suite is a layering model
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Multi-layered Architecture
Set of layers each serving different function
Can be implemented separately
Lower layers provides a service to the layer directly above it by means of an interface
Imagine layer as software implementations that perform specific functions
Imagine interface as a set of procedure calls with parameters
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Layered Architecture Benefits
Divide complex operations into manageable groups
Can change one layer without affecting others
Can mix different technologies and suppliers for different layers
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Layered Architecture Model
Layered architecture advantages is clear but:
How many layers is needed?
What function should be at each layer?
International Organization for Standardization (ISO)
Seven layer model: Open Systems Interconnection (OSI)
Developed in the 1980s
To free users from proprietary standards which were being used by vendors to lock customers into their network architectures
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TCP/IP vs OSI Model
Source: Douglas, C., 2016. Computer Networks and Internets
Internet TCP/IP Model
Open System Interconnection Networking Model
TCP/IP Layer 5 maps to Layer 5-7 in OSI
Course is focused on TCP/IP model
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Layer 1: Physical Layer Protocols
Concern with transmission medium and the associated hardware
Specification about:
Electrical properties
Radio frequencies
Signals
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Layer 2: Network Interface
Concern with communication between higher layers of protocols, which are usually software
And the underlying network, which is implemented in hardware
Specifications about:
Network addresses
Maximum packet size that a network can support
Protocols used to access the underlying medium
Hardware addressing
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Layer 3: Internet
Concern with communication between two computers across the Internet
Across multiple interconnected networks
Also known as network layer
Specifications about:
Internet addressing structure
Format of Internet packets
Methods for dividing packets into smaller packets for transmission
Mechanisms for reporting errors
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Layer 4: Transport
Concern with communication between two application programs
Specifications about:
Maximum receiver rate
Congestion control
Delivery of data
Ordered, no duplication, no error
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Layer 5: Application
Concern with how a pair of applications interact when they communicate
Specifications about:
Email exchange
File Transfer
Web Browsing
Telephone services
Video conferencing
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Communicating Between Layers
Source: Douglas, C., 2016. Computer Networks and Internets
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Layered Communication
Application
Transport
Internet
Network Interface
Application
Transport
Internet
Network Interface
Communication Flow
Host 1
Host 2
Interfaces
Layers
Peers
Physical
Physical
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Headers and Layers
Each layer will add their own information
Header: additional information added/removed by the corresponding layer
Not necessary of the same size for each header
Example: Port number (transport), IP address (Internet)
Source: Douglas, C., 2016. Computer Networks and Internets
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Practice 1.4
Briefly describe the functions of the five layers in the Internet model.
B
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Reading
Douglas, C. (2016). Computer Networks and Internets, Global Edition (6th ed.). Pearson Education. ISBN: 978-1292061177 Chapter 1
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End of Lesson
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