Computer Science - 4CP0 PearsonEdexcel

Networks

Overview

Almost nothing a computer does today happens in isolation. A phone checking the weather, a laptop backing up to the cloud, a till in a shop confirming a card payment: every one of these is a conversation between machines, carried out over a network according to rules both sides agree to follow. This lesson opens up how that conversation actually works.

You will compare network types and usage models, wired versus wireless connections, and how speed is measured, before going layer by layer through the protocols that get a message from one device to another: physical topologies, the four-layer TCP/IP model, packet switching, and the specific protocols behind the web, file transfer and email.

Objectives

Understand why computers are connected in a network
Understand the different types of networks (local area network (LAN), wide area network (WAN), personal area network (PAN)) and usage models (client-server, peer-to-peer)
Understand wired and wireless connectivity
Understand that network data speeds are measured in bits per second (Mbps, Gbps)
Understand the role of and need for network protocols (Ethernet, Wi-Fi, TCP/IP, HTTP, HTTPS, FTP, email (POP3, SMTP, IMAP))
Understand that data can be transmitted in packets using layered protocol stacks and the 4-layer TCP/IP model (application, transport, network, data link)
Understand characteristics of network topologies (bus, ring, star, mesh)
Understand the different mobile communication standards (3G, 4G and subsequent generations)

Lesson Note

A network is two or more devices connected together so they can communicate and share resources. Computers are networked for three overlapping reasons: to share hardware such as printers and storage, so an organisation buys fewer devices; to share data so people do not need to carry files between machines on removable media; and to communicate, from email to video calls to multiplayer games. A standalone computer can do none of this; the moment it needs another device's help, it needs a network.

Available on the Green Bridge App

Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.

Full lesson notes with diagrams

AI-powered learning assistant

Study offline, anytime, anywhere

Download Mobile App Download Desktop App

Available on Android, Windows, macOS, and Linux

Lesson Evaluation

Congratulations on completing the lesson on Networks. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.

You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.

Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.

Which type of network connects a person's own nearby devices, such as a phone and a pair of wireless earbuds? A) LAN B) WAN C) PAN D) VPN Answer: C
Which network topology connects every device individually to a central switch? A) Bus B) Ring C) Star D) Mesh Answer: C
Which protocol is used to send an email from a client to a mail server? A) FTP B) SMTP C) HTTP D) IMAP Answer: B
In the TCP/IP model, which layer is responsible for adding source and destination IP addresses to data? A) Application B) Transport C) Network D) Data link Answer: C
Network data transfer speeds are typically measured in: A) Bytes per second B) Bits per second C) Hertz D) Packets per second Answer: B