Introduction to Computer Networks

Introduction to Computer Networks

• Computer networks are a collection of autonomous computers interconnected by a single technology, allowing information exchange.
• Early computer systems were centralized, residing in large rooms.
• The 1970s and 1980s saw the merging of computer science and data communications, fundamentally altering the industry.
• The concept of a single computer serving an entire organization's computation is outdated.

Communication Components

• Information is a critical resource in the modern world, utilized in business and daily life.
• Sharing information across different locations is crucial.
• Data communication involves exchanging information. This exchange utilizes a transmission medium/channel.
• Data communication systems have five key components:
  • Message: the information to be shared.
  • Sender: the device initiating the message.
  • Receiver: the device receiving the message.
  • Transmission medium: the physical path connecting sender and receiver (e.g., copper wire, fiber optics).
  • Protocol: a set of rules governing data transfer.

Communication Model

• The core goal of communication systems is to exchange data between two parties.
• Key elements include:
  • Source: the device generating the data (e.g., personal computers, telephones).
  • Transmitter: modifies the data into a transmittable format (e.g., converts digital signals to analog signals).
  • Transmission system: the pathway for signal transmission (single line or complex network).
  • Receiver: converts the received signal back into a usable format for the destination device.
  • Destination: receives the converted data.

Key Communications Tasks

• Effective computer networks necessitate comprehensive tasks:
  • Utilizing transmission facilities efficiently (multiplexing, congestion control).
  • Establishing proper interfaces between devices and the transmission system.
  • Generating interpretable signals for communication.
  • Ensuring synchronization between sending and receiving devices.
  • Establishing exchange protocols/agreement for data transfer.
  • Implementing error detection and correction mechanisms.
  • Implementing flow control to prevent information overload.
  • Network management to configure, monitor, manage, and adapt to network growth
  • Addressing and routing data correctly
  • Data formatting agreement

Network Types

• Computer networks are categorized based on various factors, including: size, architecture, and topology.
  • Local Area Network (LAN): Connects devices within a limited geographical area like a building or campus.
  • Wide Area Network (WAN): Spans large geographical areas, connecting devices across cities or countries.
  • Metropolitan Area Network (MAN): Connects devices in a city.
  • Personal Area Network (PAN): Very small networks, often for connecting devices close to a person

Peer-to-Peer Networks

• These networks lack dedicated servers
• All computers are equal peers, serving as both clients and servers
• Resource sharing occurs across all computers in the network
• Easier to set up but has limited scalability when the number of users and their needs grows.

Client/Server Networks

• These networks have dedicated servers
• Servers perform tasks and handle users' requests from the network
• Easier to maintain security and manage resources on a centralised system
• More complex, but scales better than peer-to-peer when used in large-scale networks

Network Topology

• Network topology refers to the physical layout of devices and connections in a network.
  • Bus Topology: Device connections form a single line.
  • Star Topology: Devices connect to a central hub/switch.
  • Ring Topology: Devices form a closed circular loop.
  • Mesh Topology: Devices are interconnected in a more complex interconnected manner
  • Hybrid Topology: combines different topologies to suit specific needs.

Protocols and Architectures

• Protocols are rules for computer network communication.
• The OSI reference model is a theoretical framework for network architecture, dividing network functions into seven layers.
• The TCP/IP model (Transmission Control Protocol/Internet Protocol) is a reference model for the Internet, with four layers.

Application of Computer Networks

• Computer networks provide resource sharing among users and computers
• Networks are widely used in business
• Connect all business departments
• Share files, programs, printers, data, resources
• Computer networks enable home users for communication and information access.
• The Internet is a globally interconnected network of networks.
• Mobile users utilize networks for communication, data access, and other applications, frequently using Wi-Fi connections.

This quiz explores the fundamentals of computer networks, including their evolution and essential components. You'll learn about how computers communicate and the significance of data communication in various contexts. Test your knowledge of networks, data exchange, and key communication elements.