Network Models, Protocols, and Standards

Overview

• Focus on Network models, Protocols and standards
• Breakdown of data communication into areas like Components, Data representation and Data flow
• Standards include topics like Networking, Internet, LANs and WANs, Distribution processing, Criteria, Structure

What is Data Communication?

• Telecommunication is communication at a distance.
• Data is information translated into an efficient form for processing.
• Within a computer information system, data is represented by binary units of 0s and 1s.
• Data communications is the exchange of data between two devices using a transmission medium like a wire cable.

Types of Data used in Data Communication

• Text data consists of words, sentences, or paragraphs, typically stored as ASCII code.
• Numeric data is represented using decimal, hexadecimal, octal, or binary number systems.
• Audio data comprises continuous waveform signals, like music or speech.
• Video data is motion pictures creating actions and movement, typically produced by video camera.
• Image data includes charts, graphs, pictures, sketches, and freehand drawings, represented by bit patterns.

Representing Color as Binary Bits (Example)

• Orange is represented as RGB (255,128,0) and a binary code of 11111111 10000000 00000000.
• Baby pink is represented as RGB (255,210,210) and a binary code of 11111111 11010010 11010010.
• Pine green is represented as RGB (0,110,25) and a binary code of 00000000 01101110 00011001.

A Brief History of Data Communication

• 1838: Samuel Morse and Alfred Veil invented the Morse Code telegraph system.
• 1876: Alexander Graham Bell invented the telephone.
• 1930: Development of ASCII Transmission Code.
• 1943-46: Electronic Numerical Integrator and Calculator (ENIAC) was built during WWII by the USA.
• 1950: IBM released its first computer, IBM 710.
• 1960: IBM released the first commercial computer, IBM 360.

Data Communication Characteristics

• Effectiveness depends on three fundamental characteristics: delivery, accuracy, and time.
• Delivery: The system must deliver data to the correct destination.
• Accuracy: The delivery must be accurate.
• Time: Minimize time spent transmitting and receiving data.

Components of Data Communication

• There are five key components in data communication
• Message: Information to be communicated.
• Sender: Device sending the data message, like a computer or workstation.
• Receiver: Device receiving the data messages.
• Medium: Physical path for the message from sender to receiver, e.g., twisted pair wire, fiber optic cable, radio waves.
• Protocol: Set of rules governing data communications; without it, devices can be connected but not communicate.

Data Flow

• Buses and networks facilitate communication between interconnected individual devices.
• The flow of information or data between nodes can occur in various forms.
• There are three types of data flow: simplex, half-duplex, and full-duplex.

Simplex Communication

• Data can flow in only one direction.
• Data is not moved in both directions; it uses a one-way street approach.
• The communication is one-way, either sending or receiving data.
• The direction of flow does not change.

Half-Duplex Communication

• Data can flow in both directions, but not simultaneously.
• Utilizes one way at a time communication.
• Devices with half-duplex mode can send and receive data, but not at the same time.

Full-Duplex Communication

• Data can flow in both directions simultaneously.
• It provides the fastest speeds and does not need to wait to send data.

Pros of Data Communication

• Enhances communication and availability of information.
• Allows for more convenient resource sharing.
• Makes file sharing easier.
• Highly flexible.
• Inexpensive system.
• Increases cost efficiency.
• Boosts storage capacity.

Cons of Data Communication

• It lacks independence.
• It poses security difficulties.
• It lacks robustness (if the server is down, all clients are down).
• It allows for more significant risk of computer viruses.
• It requires an efficient handler.