Computer Networks Overview

Computer Networks

• A computer network is a collection of interconnected computers and resources allowing communication between them.
• Networks connect devices (computers, printers, servers) via communication links.
• Resources that can be shared include PCs, laptops, servers, mainframes, printers, and file servers.

Network Usages

• Data sharing
• Software sharing
• Hardware sharing
• Personal information sharing
• E-commerce
• Person-to-person communication
• Entertainment
• Game playing
• Client-server applications
• Remote communications

Advantages of Computer Networks

• Sharing hardware (scanners, printers) reduces costs.
• Accessing data on other computers keeps everyone updated on the latest information.
• Enables sharing of internet access.
• Allows users to run programs installed elsewhere on the network.

Network Bandwidth

• Bandwidth measures how much data can be sent and received at one time.
• Bandwidth is measured in bits, megabits, or gigabits per second.

Physical Topologies

• Physical topology describes the physical layout of the network.
• Common topologies include:
  • Mesh
  • Star
  • Bus
  • Ring

Bus Topology

• Multiple devices connect to a single cable (backbone).
• Communication flows in both directions along the cable.
• Devices communicate without needing to go through a central server.
• Limited by the number of taps and the distance between taps.
• Signal strength weakens as it travels along the backbone.
• Collisions can occur if multiple devices transmit simultaneously.

Bus Topology Advantages

• Easy to install.
• Uses less cabling than Mesh or Star when small network.

Bus Topology Disadvantages

• A break in the cable stops all transmissions.
• Difficult to add new devices.
• Troubleshooting individual issues can be difficult.
• Not suitable for large networks.

Star Topology

• Each device has a dedicated connection to a central hub or switch.
• Data passes through the central device to reach other devices.
• More robust than bus topology; failure in one connection does not affect others.
• Easy to install and reconfigure.
• Easier to isolate and troubleshoot problems.

Star Topology Disadvantages

• Dependent on the central hub/switch.
• Failure of the central hub disrupts the entire network.

Tree Topology

• Variation of star topology.
• Not all devices connect directly to the central hub.
• Secondary hubs are used to expand the network.

Tree Topology Advantages/Disadvantages

• Similar advantages and disadvantages as the star topology but offering further expansion options.

Ring Topology

• Devices are connected in a closed loop.
• Signals travel in one direction around the ring.
• Each device acts as a repeater, regenerating the signal.

Ring Topology Advantages

• Easy to install and reconfigure.
• Fault isolation is simplified. (Token system)

Ring Topology Disadvantages

• Unidirectional traffic.
• A break in the ring can disrupt the entire network.

Explore the fundamentals of computer networks, including their structure, usages, advantages, and the concept of bandwidth. This quiz will help reinforce your understanding of how interconnected devices communicate and share resources effectively.