Chapter 1 · Computer Networks
1.2Network Architecture and Basic Concepts
How a network is designed, what it is made of, and how data travels across it in small packets.
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A house needs a plan before it is built. The plan shows where each room goes and how people move between rooms. A computer network needs a plan too. This topic explains that plan, called network architecture, and then shows how data actually travels across a network.
Network architecture
So the architecture answers two questions. Where does each device sit? And how does data get from one device to another?
A server is a powerful computer that gives files or services to other computers. In Figure 1.2 of the book, "Network architecture shows how devices and components are organized in a network", the Internet sits at the top. Below it is a router, and the router joins a computer, a laptop, a server, a mobile phone and a printer.
What it is made of
The book names three parts:
- Hardware is the physical equipment: computers, servers, cables and routers.
- Software is the programs that run the network.
- Communication rules are the agreed ways devices talk, so that every device understands every other device.
These three are also a good answer to the exercise question "Name any two components of a computer network."
Why a good design matters
A good architecture helps the network work efficiently. It also supports future expansion. In simple words, a well-planned network runs smoothly today and can grow tomorrow, for example when a school adds a new computer lab.
The book's CLASS ACTIVITY asks the class to match pictures or names of devices with their functions and then discuss the answers. Your instructor leads this. The devices themselves are taught in topic 1.4.
How a network sends data
Big files do not travel in one piece. The book describes the journey in clear steps:
- A network works by sending data from one device to another.
- Data is broken into small packets before transmission. A packet is a small piece of the data.
- These packets travel through cables or wireless signals.
- Networking devices guide packets to the correct destination.
- The receiving device reassembles the packets into the original data.
The book says this process allows smooth and fast communication.
Practice this topic
Short questions
1.What is network architecture?2 marks
Answer
From the book: "Network architecture is the overall design of a computer network. It shows how computers, servers, and other devices are arranged (as shown in Figure 1.2). It also defines how data is transmitted across the network." The book's Summary (p.17): "Network architecture is the design and organisation of a network, including how devices are connected and how communication takes place."
2.Name any two components of a computer network.2 marks
Answer
From the book: "Network architecture includes hardware, software, and communication rules." Any two of these: hardware, software, communication rules. The book also names the devices it arranges: "computers, servers, and other devices". (Topic 1.4 explains the networking devices one by one.)
3.Why is a good network architecture important?2 marks
Answer
From the book: "A good architecture helps the network work efficiently. It also supports future expansion of the network."
4.What happens to data before transmission, and what does the receiving device do with it?2 marks
Answer
From the book: "A network works by sending data from one device to another. Data is broken into small packets before transmission." The packets travel to the receiver, which "reassembles the packets into the original data. This process allows smooth and fast communication."
5.What is the role of networking devices in sending packets?2 marks
Answer
From the book: "These packets travel through cables or wireless signals. Networking devices guide packets to the correct destination."
6.What does the receiving device do when packets arrive?2 marks
Answer
From the book: "The receiving device reassembles the packets into the original data. This process allows smooth and fast communication."
Long questions
1.Explain network architecture and describe the main components of a computer network.8 marks
Answer
Cover both parts, using the book's text from 1.2:
- Definition (verbatim): "Network architecture is the overall design of a computer network. It shows how computers, servers, and other devices are arranged (as shown in Figure 1.2). It also defines how data is transmitted across the network." The Summary (p.17) adds: "Network architecture is the design and organisation of a network, including how devices are connected and how communication takes place."
- Main components (verbatim): "Network architecture includes hardware, software, and communication rules." Name the devices the book lists: "computers, servers, and other devices". Figure 1.2 ("Network architecture shows how devices and components are organized in a network") shows the Internet joined to a router, and the router joined to a computer, a laptop, a server, a mobile phone and a printer.
- Why it matters: "A good architecture helps the network work efficiently. It also supports future expansion of the network."
- How the network works: "Data is broken into small packets before transmission. These packets travel through cables or wireless signals. Networking devices guide packets to the correct destination. The receiving device reassembles the packets into the original data." Note: the networking devices themselves (NIC, switch, router, modem, wireless access point) are explained in topic 1.4; a full exam answer can add them from there.
Aim for 200-300 words.
2.Explain how a network sends data from one device to another.5 marks
Answer
Follow the book's steps in order (1.2, printed pages 2 to 3):
- "A network works by sending data from one device to another."
- "Data is broken into small packets before transmission."
- "These packets travel through cables or wireless signals."
- "Networking devices guide packets to the correct destination."
- "The receiving device reassembles the packets into the original data."
- Result: "This process allows smooth and fast communication."
Aim for 120-180 words.
In this chapter
- 1.1Introduction to Computer Networks
- 1.2Network Architecture and Basic ConceptsYou are here
- 1.3Types of Computer Networks
- 1.4Networking Devices
- 1.5Network Topologies
- 1.6Network Models and Layers
- 1.7Network Protocols and Services
- 1.8IP Addressing and Subnetting
- 1.9Home Network Setup and Configuration
- 1.10Wi-Fi Security and Router Configuration
- 1.11Network Diagnostic Tools and Commands
- 1.12Network Performance
- 1.13Network Load Balancing
- 1.14Network Security
- 1.15Data Backup and Recovery
- 1.16Usability and Security Tradeoffs