Fundamentals of computer networks

What is a computer network?

Two or more computers connected for sharing resources/data

State one advantage of computer networks.

Share files, hardware (printers), internet connection, collaboration

State one disadvantage of computer networks.

Security risks, virus spread, reliance on network hardware

What is a PAN (personal area network)?

Small network for personal devices, often Bluetooth

What is a LAN (local area network)?

Network covering a small area (e.g., home, school, office)

Who owns or manages a LAN?

Usually a single person or organisation

What is a WAN (wide area network)?

Network covering large geographic area, e.g., Internet

How is WAN ownership different from LAN?

WAN is often collectively or distributed owned/managed

Give an example of WAN.

Internet

Can networks be wired or wireless?

Both

State an advantage of wired networks.

Faster speeds, more secure, less interference

State an advantage of wireless networks.

No cables needed, flexible use, easier for mobile devices

What is a disadvantage of wired networks?

Need cables, less mobile, harder to install/change

What is a disadvantage of wireless networks?

Potential interference, lower speed/security than wired

What cable types are used for wired networks?

Fibre optic, copper (Ethernet)

State an advantage of fibre optic over copper cable.

Faster, longer distance, more reliable, less signal loss

When is copper used for network cables?

Short distances, cheaper installations

What is a network protocol?

Agreed rules defining data transmission and communication between devices

What does HTTP stand for?

HyperText Transfer Protocol (web data)

What does HTTPS provide?

Encrypted (secure) version of HTTP for secure web transactions

What is SMTP used for?

Sending email messages

What is IMAP used for?

Reading/storing email messages on a mail server

What is TCP?

Transmission Control Protocol—reliable, ordered communication between devices

What is IP?

Internet Protocol—handles addressing and routing of packets

What is the purpose of protocols in networks?

Ensure devices can understand and interpret exchanged data correctly

What is network security?

Protecting data, devices and network resources against threats

How does authentication help network security?

Checks user identity before access is granted (e.g., passwords)

What does encryption do in network security?

Changes data into unreadable format without correct key, protects privacy

What is a firewall?

Network security device/software that monitors and filters incoming/outgoing traffic

What is a MAC address?

Unique physical address for a network adapter/device

What is MAC address filtering?

Allows/blocks devices from accessing network based on their MAC address

How can authentication and encryption work together?

Authenticate user, then encrypt data transmission for security

How can firewalls increase security?

Block unwanted/malicious traffic or sites based on rules

How can MAC address filtering increase security?

Only approved devices allowed onto network

What is the purpose of a network interface card (NIC)?

Allows a computer/device to connect to a network

What is the 4 layer TCP/IP model?

Standard structure for how network data is sent/received

Name the TCP/IP layers in order.

Application, Transport, Internet, Link

What operates at the application layer?

Network applications (web browser, email); protocols like HTTP, HTTPS, SMTP, IMAP

What is the function of the transport layer?

Sets up communication, agrees settings (e.g., packet size), reliable transfer (TCP)

What is the function of the internet layer?

Addresses, packages, routes data across network (IP)

What is the function of the link layer?

Controls hardware for network (NIC), device drivers, handles transmission over physical network

Name a protocol used at the application layer.

HTTP, HTTPS, SMTP, IMAP

Name the protocol at the transport layer.

TCP

Name the protocol at the internet layer.

IP

Which layer interacts with network hardware?

Link layer

How do layers make networking easier?

Break into manageable, defined functions; each layer solves a specific problem

Why is HTTPS better than HTTP for online banking?

Encrypts transactions, more secure against interception

Give an example of a network security risk.

Virus infection, hacking, data interception

How can encryption help protect WiFi traffic?

Prevents outsiders reading data sent over the wireless network

How are MAC addresses useful for security?

Controls which devices connect, can track/block by device ID

What does firewall software/devices filter?

Traffic by IP, port, MAC, content, malware signatures

Why are protocols essential for internet communication?

Ensure computers with different hardware/system can exchange data

What does packet mean in networking?

Small chunk of data sent over a network

How are packets transmitted?

Sent individually, reassembled by receiver; follow protocols/routing

What can happen if packet is lost in transit?

Transport layer resends (TCP) to ensure reliability

What role does the NIC link layer play?

Provides the physical connection, handles the low-level transfer

What is WPA/WPA2?

Wireless Protected Access; standards for encrypting WiFi traffic

Why is wireless less secure than wired?

Signals can be intercepted more easily; require stronger encryption/authentication

What measurement is used for network speed?

Bits per second (bps), megabits/s, gigabits/s

Why use fibre optics for backbone of WAN?

High speed, less interference, can run longer distances

How does a switch differ from a hub?

Switch directs traffic to correct device, hub sends data to all devices

What is a router?

Device connecting networks, directing traffic by IP address

What's the role of a modem?

Converts digital data for transmission over phone lines/broadband

How is data collision prevented on networks?

Managed with switches, protocols, and cabling schemes

What is a mesh network?

All nodes connect directly and dynamically to many others, redundancy

Why is redundancy important in networks?

Ensures network survives link failures, increases reliability

Give example of protocol for secure file transfer.

FTPS, SFTP

What is SSID in wireless?

Network name/identifier for WiFi access point

What is a subnet?

Segment of a network to improve performance/security

State two network hardware items.

Router, switch, hub, NIC, cable

What is peer-to-peer network?

All computers equal, share resources directly

What is a client-server network?

Servers provide resources/services to client computers

What device connects LANs to the Internet?

Router

What is bandwidth?

Maximum data transfer rate of a network

What can slow down a network?

Low bandwidth, many users, interference, outdated hardware

How does MAC filtering work?

Allows/block devices based on their hardware address

What is Ethernet?

Standard technology for wired LAN; uses copper or fibre cable

What is an IP address used for?

Identifies and locates a device on network/Internet

How is a device prevented from joining a network?

MAC filtering or firewall rules

Why do data packets need addressing?

Tell network where each packet should go

Give a use for SMTP protocol.

Sending outgoing emails

Give a use for IMAP protocol.

Reading emails from server/mailbox

What is network topology?

Physical/data layout of devices in a network (star, ring, mesh, bus)

Why could a network become unavailable?

Hardware failure, attack, bad configuration, overload

What increases risk of wireless attacks?

No encryption, weak passwords, open signals

Why must network protocols be agreed in advance?

Prevents confusion, enables communication between different hardware/software

What is the main job of the transport layer?

Sets up reliable connections and ensures packets get through

What is the main job of the internet layer?

Addresses, routes packets to destination

What is the main job of the application layer?

Executes the actual network program (browser, email client)

What is the main job of the link layer?

Handles transmission of actual bits on cable/wireless

How does firewall improve network safety?

Blocks unauthorised traffic, can filter based on rules

Why is the internet called the biggest WAN?

Connects computers globally using distributed ownership

What can firewalls not always stop?

Attacks from inside network, physical access threats

Why are wireless networks popular at home?

Easy setup, no cables, works for phones/tablets/laptops

Why might you choose wired network for a business?

Faster, more reliable, easier to secure