Computer Networks Overview

Computer Networks Overview

• Computer networks connect computing devices to communicate and share resources. Connections can be wired (cables) or wireless (radio waves, infrared).

Key Concepts

• Networking: A method where multiple computers in different locations share processing capabilities.

• Data Communication: Sharing information (data) between devices in a network.

• Hardware Sharing: Sharing computer resources such as printers or hard drives.

• Software Sharing: Sharing software programs or applications across the network.

• Centralized Administration: Managing a network from a central point simplifying maintenance and support.

• Distributed Processing: Dividing tasks across multiple computers for improved performance, reliability and reduced processing time, often across geographical areas.

Protocols

• Protocol: Guidelines for implementing communication between computers in a network.

Networking Layers

• Networks operate in layered structures, enabling modularity and abstraction.
• Each layer performs specific tasks.

Message Encapsulation

• Encapsulation is a method to structure complex network functions, preventing their components from interfering with each other.
• Data is encapsulated or added to each layer to prepare it for transport.

OSI Model

• OSI (Open Systems Interconnection): A standard model defining network layers and services.
• It provides a framework for standardization across various network protocols.
• Multiple protocols can operate on each layer.

TCP/IP

• TCP (Transmission Control Protocol): Breaks messages into packets, ensures delivery, and assembles packets at the destination.
• IP (Internet Protocol): Manages the routing of packets through a network to a final destination.

Network Topologies

• Topology: The pattern of interconnection of nodes in a network.

  • Common factors considered while choosing a topology are cost, reliability, and flexibility.

• Bus Topology: All devices are connected to a single cable.

  • Advantages: Easy to implement, low cost
  • Disadvantages: Single point of failure, limited length, low efficiency.

• Star Topology: All devices are connected to a central device (hub or switch).

  • Advantages: Easy to add new devices, centralized management, high performance, less prone to failure than bus topology
  • Disadvantages: Single point of failure of central device, costlier implementation.

• Ring Topology: Devices are connected in a closed loop. Data travels unidirectionally in a loop using a token.

  • Advantages: No collisions, better performance than Bus topology, each device has equal access to the network.
  • Disadvantages: Single point of failure of one device, failure of one device affects the whole network.

• Mesh Topology: All devices are interconnected, creating redundant paths.

  • Advantages: High reliability, fault tolerance, high bandwidth, efficient data transmission.
  • Disadvantages: High cost, complex implementation, difficult to manage.

• Partial Mesh Topology: Devices are partially interconnected, combining aspects of different topologies, providing a balance of reliability.

  • Advantages: High availability compared to bus or ring
  • Disadvantages: Can be more expensive and difficult to manage compared to simpler topologies

• Peer-to-Peer Topology: Devices act as equals in the network. Simple, less expensive solution for small networks.

  • Advantages: Inexpensive relative to other options.
  • Disadvantages: Poor scalability, difficulty in managing resources.