Computer networks, connections and protocols Study Guide

Networks facilitate communication and resource sharing between computing devices. These can be broadly categorised as wired or wireless based on their physical connection medium. Wired networks, like Ethernet, use physical cables (e.g., copper or fibre optic) to transmit data, offering high speed, reliability, and security. Wireless networks, such as Wi-Fi, use electromagnetic waves (radio waves) to transmit data without physical cables, providing flexibility and mobility. Both types of networks rely on protocols and layers to function effectively. Protocols are agreed-upon sets of rules that govern how data is transmitted and received across a network. Without protocols, devices would not be able to understand each other's transmissions. Examples include TCP/IP, HTTP, and FTP. Network architecture is often conceptualised using a layered model, such as the TCP/IP model or the OSI model. These models divide the complex task of network communication into smaller, manageable layers, each responsible for a specific function. For instance, the transport layer handles end-to-end communication, while the network layer manages addressing and routing. This layered approach simplifies design, allows different technologies to work together, and makes troubleshooting easier by isolating issues to specific layers. Understanding these components is crucial for designing, managing, and securing modern computer networks, as well as for troubleshooting common network problems.

Networks are interconnected systems that allow devices to communicate and share resources. They are fundamental to modern computing, enabling data exchange between computers, printers, servers, and other devices. The advantages of networks include sharing hardware like printers, sharing software licenses, centralized data storage for easier backup and access, and enhanced communication through email and instant messaging. However, networks also have disadvantages such as increased security risks, reliance on a central server (if applicable) which can be a single point of failure, and the cost of setup and maintenance. Network topologies describe the physical or logical arrangement of connected devices. Common topologies include bus, and star. In a star topology, all devices connect to a central hub or switch. If the central device fails, the entire network segment goes down, but individual cable failures only affect one device. This topology is easy to set up and manage, and adding new devices is straightforward. In a bus topology, all devices share a single communication line. Data travels along this bus, and each device checks if the data is intended for it. Collisions can occur if two devices transmit simultaneously, and a break in the main cable can bring down the entire network. While historically inexpensive, bus topologies offer poor fault tolerance and are less common in modern networks. Understanding these concepts is crucial for designing, implementing, and maintaining efficient and reliable computer systems.