computer network
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Absolutely. I’ve organized the material into four lecture study documents, plus a short syllabus/exam guide. I’m keeping the content based on your uploaded notes rather than adding outside material. The module catalogue confirms that Lectures 1–4 cover Weeks 1–4 respectively.
📘 ICT 1216Y(1) — Introduction to Computer Networks
Master Study Guide — Lectures 1–4
---
🟦 LECTURE 1 — INTRODUCTION TO COMPUTER NETWORKS
1. What is a Computer Network?
A computer network is a group of computers/devices connected to each other.
Main purpose
The main aim is resource sharing between devices.
Examples:
Sharing files
Sharing printers
Sharing applications
Sharing an Internet connection
Communicating between users
---
2. Three Levels of Network Communication
Your notes introduce communication at three high-level layers:
1. Hardware
2. Operating System
3. Application
Hardware level
The physical connection can be:
Wired
Wireless
A NIC (Network Interface Card) allows a device to connect to a network.
The NIC contains a 48-bit (6-byte) hardware/MAC address that identifies the device.
Operating System level
The OS uses IP addresses to identify/find computers on networks.
Your notes distinguish:
Address Main purpose
MAC address Identifies a computer on a local network
IP address Used to identify/find a computer across networks/Internet
Application level
Applications communicate using client/server architecture.
A server listens on a particular port number, which identifies an application/service on a computer.
⭐ Exam idea
Be able to explain:
MAC → local device identification
IP → network/Internet identification
Port → application/service identification
---
3. Network Components
NIC
A Network Interface Card provides the hardware interface for network communication.
Types:
Wired NIC
Wireless NIC
Wireless NICs use antennas/radio waves, while wired NICs use cables.
---
Hub
A hub connects multiple devices into a network segment.
Important characteristics:
Broadcasts incoming data to all ports
Operates in half-duplex
Can experience collisions
Lower security
Less efficient
Remember:
HUB = sends to everyone
---
Switch
A switch sends data only to the intended destination port.
Characteristics:
Uses unicast
Can operate in full-duplex
Fewer collisions
Better performance
Better security than a hub
Remember:
SWITCH = sends to the intended device
⭐ Common exam comparison
Hub Switch
Broadcast Unicast
Sends to all ports Sends to destination port
Half-duplex Can use full-duplex
More collisions Fewer collisions
Lower security Better security
---
Cables
Three types:
Twisted Pair
Copper wires
High-speed transmission
Used for Ethernet
Coaxial
Similar to traditional TV cable
Fibre Optic
Uses light beams
Very high transmission speed
More expensive
---
Router
A router connects different networks.
Your notes describe it as connecting a LAN to the Internet and connecting distinct networks.
Remember:
Switch → devices within a network
Router → connects networks
---
4. Features of Computer Networks
Important features:
Communication speed
File sharing
Backup and rollback
Hardware/software sharing
Security
Scalability
Scalability
The ability to add new components to the network.
---
5. Transmission Modes
Transmission mode describes how data travels between devices.
There are three:
Simplex
One direction only.
One device sends and the other receives.
Example:
Radio station → radio receiver
Advantage: Entire bandwidth can be used in one direction.
Disadvantage: No communication in the reverse direction.
---
Half-Duplex
Both devices can send and receive, but not simultaneously.
Example:
Walkie-talkie
Advantage: Both devices can transmit and receive.
Disadvantage: One device must wait while the other transmits.
---
Full-Duplex
Both devices can send and receive simultaneously.
Example:
Telephone system
⭐ Memorise
Simplex = →
Half-duplex = ↔ but one at a time
Full-duplex = ↔ simultaneously
---
6. Client/Server vs Peer-to-Peer
Client/Server
A central server provides resources/services to clients.
The server handles things such as:
Security
Network management
Files
Directories
Printers
Advantages
Centralized management
Better security
Good performance
Better data consistency
Easier backup/recovery
Disadvantages
Expensive
Server can become a single point of failure
Requires maintenance
Possible server bottlenecks
Scaling can require additional investment
---
Peer-to-Peer (P2P)
There is no dedicated server.
All computers have relatively equal responsibilities.
The notes describe P2P as useful for small environments, usually up to about 10 computers.
Advantages
Low cost
Direct resource sharing
Decentralized
Failure of one peer doesn't necessarily stop the whole network
Fewer central bottlenecks
Disadvantages
More difficult security management
Difficult administration
Data consistency problems
Performance can vary
Scalability limitations
⭐ Exam comparison
Client/Server P2P
Dedicated server No dedicated server
Centralized Decentralized
Easier management Harder management
Generally stronger centralized security Security harder to manage
More expensive Cheaper
Server can be bottleneck Load distributed
---
7. Types of Networks
PAN — Personal Area Network
Very small network around an individual.
Usually a few metres
Notes give approximately 2–10 devices
Examples: smartphone, laptop, smartwatch, Bluetooth devices
LAN — Local Area Network
Limited geographical area.
Examples:
Home
Office
Building
Campus
MAN — Metropolitan Area Network
Covers a metropolitan/city area and connects multiple LANs.
WAN — Wide Area Network
Covers a large geographic area, potentially countries or continents.
⭐ Size order
PAN → LAN → MAN → WAN
---
8. Network Topologies
These are listed as self-study in the lecture.
Point-to-Point
Only two devices are connected directly.
Bus
Devices connect to a common backbone cable.
Important:
Drop lines connect devices
Terminators are placed at the ends
BNC connectors are used
Ring
Each device connects to two neighbours.
Data travels sequentially around the ring.
Star
All devices connect to a central switch.
This is described as the most common topology in the notes.
Tree
An extension of star topology where multiple stars/branches are connected through switches.
---
9. Network Security
The three fundamental principles are:
Confidentiality
Only authorized people should access data.
Integrity
Data should remain accurate and unaltered.
Availability
Network services should remain accessible when needed.
CIA = Confidentiality, Integrity, Availability
Threats
Malware
Phishing
Man-in-the-Middle attacks
DoS attacks
Security measures
Firewalls
IDS/IPS
VPNs
Antivirus/anti-malware
---
🧠 Lecture 1 — Exam Focus
Know especially:
1. Definition/purpose of a computer network
2. MAC vs IP vs port
3. Hub vs switch
4. Router function
5. Simplex vs half-duplex vs full-duplex
6. Client/server vs P2P
7. PAN/LAN/MAN/WAN
8. Network topologies
9. CIA security principles
10. Common network threats and security measures
---
🟩 LECTURE 1 — FLASHCARDS
Q: What is a computer network?
A: A group of computers/devices connected together for resource sharing.
Q: What does NIC stand for?
A: Network Interface Card.
Q: What is a MAC address used for?
A: Identifying a device on a local network.
Q: What is an IP address used for?
A: Identifying/finding a device across networks/Internet.
Q: What identifies an application/service?
A: A port number.
Q: What does a hub do?
A: Broadcasts incoming data to all ports.
Q: What does a switch do?
A: Sends data to the intended destination port.
Q: What does a router connect?
A: Different networks.
Q: What is simplex?
A: One-way communication.
Q: What is half-duplex?
A: Two-way communication, but not simultaneously.
Q: What is full-duplex?
A: Two-way simultaneous communication.
Q: What is a client/server network?
A: A network where clients obtain services/resources from a central server.
Q: What is P2P?
A: A decentralized network where peers have equal responsibilities and there is no dedicated server.
Q: What are the four network sizes?
A: PAN, LAN, MAN, WAN.
Q: What does CIA stand for?
A: Confidentiality, Integrity, Availability.
---
🟨 LECTURE 2 — COMPUTER NETWORK MODELS
1. Why Layered Architecture?
Networking is complex because many hardware and software components interact.
A layered approach divides networking into smaller, manageable tasks.
Main advantages:
Divide and conquer → reduces complexity
Modularity → layers are independent
Easy modification → changing one layer should not affect others
Easy testing → layers can be tested individually
---
2. Three Important Concepts
Service
A set of actions a layer provides to the higher layer.
Protocol
Rules used by peer entities to exchange information, including message contents and order.
Interface
The mechanism through which information moves from one layer to another.
⭐ Easy distinction
Service = what a layer provides
Protocol = rules for communication
Interface = how layers communicate
---
3. OSI Model
OSI = Open System Interconnection
It is a reference model describing how information moves between applications on different computers.
It contains 7 layers.
The seven layers
From bottom → top:
1. Physical
2. Data Link
3. Network
4. Transport
5. Session
6. Presentation
7. Application
---
4. OSI Layer Functions
Layer 1 — Physical
Transmits individual bits from one node to another.
Deals with:
Physical connections
Transmission mode
Signals
---
Layer 2 — Data Link
Main concepts:
Framing
Physical addressing
Error control
Access control
It converts the raw bit stream into frames.
CRC can be used for error detection.
---
Layer 3 — Network
Main concepts:
Internetworking
Logical addressing
Routing
Packetizing
IP is associated with packetizing.
⭐ Remember:
Network layer = IP + routing
---
Layer 4 — Transport
Main concepts:
Port addressing
Segmentation/reassembly
Connection control
Flow control
Two service types:
Connection-oriented
Connectionless
---
Layer 5 — Session
Responsible for:
Setting up sessions
Maintaining sessions
Ending sessions
Synchronization/recovery
Checkpoints can be used so transmission can restart from a checkpoint if an error occurs.
---
Layer 6 — Presentation
Main functions:
Translation
Encryption
Compression
---
Layer 7 — Application
Provides network applications/services directly used by users.
Examples/functions mentioned:
File services
Mail services
Directory services
---
5. TCP/IP Model
Your lecture presents TCP/IP as a four-layer model:
1. Application
2. Transport
3. Internet/Network
4. Network Interface
Protocol examples
TCP/IP Layer Examples
Application HTTP, DNS, DHCP, SMTP
Transport TCP, UDP
Internet/Network IP, ARP, ICMP
Network Interface Ethernet
---
6. TCP/IP Layer Functions
Network Interface
Combines the OSI Physical + Data Link functions.
Responsible for physical transmission and framing/mapping IP addresses to physical addresses.
Internet/Network
IP provides:
Logical addressing
Routing
Fragmentation/reassembly
ARP
Address Resolution Protocol
Maps an IP address to a physical address.
Process:
ARP request → broadcast
ARP reply → destination provides physical address
ICMP
Internet Control Message Protocol
Used to notify hosts about problems with datagrams/network delivery.
---
7. TCP vs UDP
UDP
Connectionless
End-to-end delivery
Unreliable
TCP
Creates a virtual circuit for transmission
Reliable
Detects errors
Retransmits lost/damaged data
Uses sequence numbers
Receiver reorders segments
⭐ Exam table
TCP UDP
Reliable Unreliable
Connection-oriented Connectionless
Uses acknowledgements No equivalent reliability mechanism described in notes
Sequence numbers —
Retransmits lost/damaged data —
---
8. Application Protocols
HTTP
Transfers web data.
DNS
Maps domain names to IP addresses.
DHCP
Automatically assigns IP addresses and network settings.
SMTP
Used by email servers to send, receive and relay email.
---
🧠 Lecture 2 — Exam Focus
Highest priority:
Why layered architecture is used
Service vs protocol vs interface
All 7 OSI layers and functions
TCP/IP's 4 layers
OSI vs TCP/IP
TCP vs UDP
IP, ARP and ICMP
HTTP, DNS, DHCP, SMTP
Encapsulation/layered communication
---
🟩 Lecture 2 Flashcards
Q: Why use layered architecture?
A: To divide complex networking tasks into smaller, manageable and independent tasks.
Q: What are the three basic elements of layered architecture?
A: Services, protocols and interfaces.
Q: What is a protocol?
A: Rules governing the exchange of information between peer entities.
Q: How many OSI layers are there?
A: Seven.
Q: What is Layer 1?
A: Physical.
Q: What does the Data Link layer create?
A: Frames.
Q: Which OSI layer handles routing?
A: Network layer.
Q: Which layer handles ports?
A: Transport layer.
Q: Which layer handles encryption and compression?
A: Presentation layer.
Q: Which layer handles sessions?
A: Session layer.
Q: What are TCP/IP's four layers?
A: Application, Transport, Internet/Network, Network Interface.
Q: What does ARP do?
A: Finds a physical address from an IP address.
Q: What does ICMP do?
A: Reports datagram/network delivery problems.
Q: What is TCP?
A: A reliable, connection-oriented transport protocol.
Q: What is UDP?
A: A connectionless, unreliable transport protocol.
Q: What does DNS do?
A: Maps domain names to IP addresses.
Q: What does DHCP do?
A: Automatically assigns IP addresses and network settings.
---
🟥 LECTURE 3 — IP ADDRESSING AND SUBNETTING
The lecture specifically focuses on IPv4, fragmentation/reassembly, IP addressing, class-based addressing, subnetting, classless addressing and NAT.
---
1. Internet Protocol
IP is the protocol used to send data between computers on the Internet.
Data is divided into packets.
Each packet contains:
Sender's address
Receiver's address
---
2. IP Datagram
An IP datagram consists of:
Header + Payload/Data
Important IPv4 header fields:
Version
IHL
Type of Service
Total Length
Identification
Flags
Fragment Offset
TTL
Protocol
Header Checksum
Source Address
Destination Address
Options
Padding
---
Important Header Fields
Version
Indicates IPv4/IPv6.
IHL
Header length.
Type of Service
Used for prioritisation.
Total Length
Length of header + payload.
Identification
Helps reconstruct the original datagram after fragmentation.
Flags
Provide information related to fragmentation.
Fragment Offset
Shows the position of the fragment in the original datagram.
Fragments are in multiples of 8 bytes, except the last one.
TTL
Maximum time the packet can live on the Internet.
Protocol
Identifies the next higher-level protocol, such as TCP or UDP.
Header Checksum
Protects the header against corruption.
Source/Destination Address
Identify source and destination IP addresses.
---
3. IP Address Allocation
The lecture covers four main approaches:
1. Class-based addressing
2. Subnetting
3. Classless addressing
4. NAT
---
4. Special IP Address Rules
Host ID = all 0s
Represents the network itself.
Host ID = all 1s
Represents a direct broadcast.
All bits = 1
Limited broadcast.
Class A Net ID = all 1s
127.x.x.x is the loopback range used for internal testing.
---
5. Subnetting
Normally:
IP address = NetID + HostID
With subnetting:
IP address = NetID + SubnetID + Local HostID
Subnetting allows a site with multiple LANs to divide its address space into multiple subnets.
Some bits are borrowed from the HostID to create the SubnetID.
---
6. Subnet Mask
A subnet mask identifies which bits belong to:
Network + subnet
Host
The key rule:
1 → Network/Subnet
0 → Host
Example
IP/net ID:
128.10.12.0
Mask:
255.255.255.0
Binary:
11111111.11111111.11111111.00000000
Therefore:
First 24 bits → network/subnet
Last 8 bits → host
---
7. Classless Addressing / CIDR
In classless addressing, the network portion can contain any number of bits.
Written:
w.x.y.z/n
where n = number of network bits.
Example:
/22
means:
22 network bits
10 host bits
This allows more efficient use of IP address space.
⭐ Must know
If:
/n
then:
Host bits = 32 − n
For /22:
32 − 22 = 10 host bits
---
8. NAT
NAT = Network Address Translation
The lecture describes a site being allocated a single Internet-facing IP address while internal hosts use private addresses.
The three private address blocks shown in your notes are:
10.0.0.0 – 10.255.255.255
172.10.0.0 – 172.31.255.255
192.168.0.0 – 192.168.255.255
The NAT router maintains a NAT table mapping local IP/port combinations to global IP/port combinations.
⭐ Exam concept
A NAT router can translate:
Private IP + Port → Global IP + Port
and translate the returning traffic back to the internal host.
---
🧠 Lecture 3 — Exam Focus
This lecture is particularly important because it contains calculation/problem-solving material.
Focus heavily on:
1. Binary ↔ decimal conversion
2. IPv4 structure
3. IPv4 header
4. Fragmentation fields
5. Class-based addressing
6. Network/host IDs
7. Subnetting
8. Subnet masks
9. CIDR notation
10. NAT tables
The lecture itself lists binary-decimal conversion as a requirement.
---
🟥 Lecture 3 Flashcards
Q: What is an IP packet/datagram made of?
A: Header + payload/data.
Q: What does TTL represent?
A: The maximum time a packet can live on the Internet.
Q: What does the Identification field help with?
A: Reconstructing the original datagram after fragmentation.
Q: What does Fragment Offset indicate?
A: The position of the fragment within the original datagram.
Q: In what multiples are IPv4 fragments normally positioned?
A: Multiples of 8 bytes, except the last fragment.
Q: What is subnetting?
A: Borrowing bits from the HostID to create SubnetIDs.
Q: What is the subnetted IP structure?
A: NetID + SubnetID + Local HostID.
Q: What does a 1 in a subnet mask represent?
A: Network/Subnet.
Q: What does a 0 represent?
A: Host.
Q: What does /22 mean?
A: 22 network bits and 10 host bits.
Q: What does CIDR provide?
A: More efficient use of IP address space.
Q: What is NAT?
A: Network Address Translation.
Q: What does a NAT table map?
A: Local IP/port combinations to global IP/port combinations.
---
🟪 LECTURE 4 — INTERNET, PROTOCOLS, NETWORK EDGE & NETWORK CORE
---
1. What is the Internet?
The lecture presents the Internet as a “network of networks.”
It consists of interconnected:
Home networks
Mobile networks
Enterprise networks
ISPs
Datacenter networks
Content provider networks
---
2. Two Views of the Internet
Nuts-and-bolts view
Focuses on:
Hosts
Packet switches
Communication links
Networks
Protocols
ISPs
Packet switches include:
Routers
Switches
Communication links include:
Fibre
Copper
Radio
Satellite
---
Service view
The Internet provides services to applications such as:
Web
Streaming video
Games
E-commerce
Social media
Teleconferencing
---
3. What is a Protocol?
A protocol defines:
1. Format of messages
2. Order of messages
3. Actions taken when messages are transmitted/received
Easy way to remember:
Protocol = rules of communication
---
4. Network Edge
The network edge contains the hosts/end systems.
Examples:
Clients
Servers
Servers are often located in data centres.
---
5. Access Networks
Access networks connect end systems to an edge router.
Three examples:
Residential access networks
Institutional access networks
Mobile access networks
Important characteristics:
Transmission rate
Shared vs dedicated access
---
6. Physical Media
Two broad categories:
Guided media
Signals travel through a physical medium.
Examples:
Copper
Fibre
Coax
Unguided media
Signals travel freely.
Example:
Radio
---
Twisted Pair
Made from twisted copper wires.
The lecture gives:
Category 5
Category 6
---
Coaxial Cable
Contains two concentric copper conductors.
Can support multiple frequency channels.
---
Fibre Optic
Uses light pulses.
Advantages:
Very high speed
Low error rate
Immune to electromagnetic noise
---
Wireless Radio
Uses the electromagnetic spectrum.
Possible environmental effects:
Reflection
Obstruction
Interference
Types include:
WiFi
Cellular
Satellite
---
7. Network Core
The network core is a mesh of interconnected routers.
Packet switching works by:
1. Application message is divided into packets.
2. Packets are forwarded from router to router.
3. Packets follow a path from source to destination.
4. Each packet uses the link's transmission capacity.
---
8. Transmission Delay
For a packet of L bits sent over a link with transmission rate R bits/sec:
\[
\boxed{d_{trans}=\frac{L}{R}}
\]
Example from the lecture:
L = 10 Kbits
R = 100 Mbps
Transmission delay = 0.1 ms.
⭐ Memorise this formula
Transmission delay = Packet size ÷ Transmission rate
---
9. Store-and-Forward
A router must receive the entire packet before transmitting it onto the next link.
For two links, assuming zero propagation delay:
\[
\boxed{\text{End-to-end transmission delay}=\frac{2L}{R}}
\]
---
10. Queueing and Packet Loss
If the arrival rate of packets is greater than the link's transmission rate:
1. Packets wait in a queue.
2. The queue can grow.
3. If router memory/buffer becomes full, packets can be dropped.
⭐ Key relationship
Arrival rate > transmission rate → queueing → possible packet loss
---
11. Forwarding vs Routing
This is a very important distinction.
Forwarding
A local action.
It moves an arriving packet from an input link to the appropriate output link.
Routing
A global action.
It determines the paths packets should take from source to destination.
⭐ Memorise
Forwarding = where should this packet go next?
Routing = what overall path should packets take?
---
12. Circuit Switching
Circuit switching reserves resources for a communication session/call.
Characteristics:
Dedicated resources
No sharing during the call
Guaranteed/circuit-like performance
Traditionally used in telephone networks
---
13. FDM vs TDM
FDM — Frequency Division Multiplexing
Frequency is divided into bands.
Each call gets its own frequency band.
TDM — Time Division Multiplexing
Time is divided into slots.
Each call gets periodic time slots.
Easy memory:
FDM → Frequency
TDM → Time
---
14. Packet Switching vs Circuit Switching
Packet Switching Circuit Switching
Resources shared Resources reserved
Good for bursty data Good for continuous communication
No call setup Requires resource allocation
Congestion can occur Circuit-like guaranteed performance
Packets may queue/loss can occur Reserved resources can be idle
The lecture specifically highlights packet switching's resource sharing and suitability for bursty data, while congestion can cause delay/loss.
---
15. Internet Structure
Access ISPs connect users to the Internet.
These ISPs must themselves be interconnected so that hosts can communicate with each other.
The resulting system is a complex network of networks.
---
IXP
IXP = Internet Exchange Point
It provides infrastructure allowing different networks/ISPs/content providers to interconnect.
Peering
Networks agree to connect directly to exchange traffic.
---
16. Tier-1 ISPs
At the centre of the Internet are highly connected large networks.
The lecture refers to Tier-1 commercial ISPs as having national/international coverage.
It also discusses content-provider networks such as large companies connecting their data centres through private networks.
---
17. Bits vs Bytes
This is useful for calculations.
Basic relationships
\[
1\text{ byte}=8\text{ bits}
\]
The lecture gives:
1 Kb = \(10^3\) bits
1 Mb = \(10^6\) bits
1 Gb = \(10^9\) bits
1 KB = \(2^{10}\) bytes
1 MB = \(2^{20}\) bytes
1 GB = \(2^{30}\) bytes
1 TB = \(2^{40}\) bytes
⚠ Exam trap
b = bit
B = Byte
And:
1 Byte = 8 bits
---
🧠 Lecture 4 — Exam Focus
Prioritise:
1. Definition of a protocol
2. Network edge vs network core
3. Access networks
4. Guided vs unguided media
5. Physical media comparisons
6. Packet switching
7. Store-and-forward
8. Transmission delay formula
9. Queueing and packet loss
10. Forwarding vs routing
11. Circuit switching
12. FDM vs TDM
13. Packet vs circuit switching
14. Internet as a network of networks
15. ISP, IXP and peering
16. Bits vs bytes
---
🟪 Lecture 4 Flashcards
Q: What is the Internet?
A: A network of interconnected networks.
Q: What is a protocol?
A: Rules defining message format, order and actions during communication.
Q: What is the network edge?
A: The part containing hosts/end systems such as clients and servers.
Q: What is the network core?
A: A mesh of interconnected routers.
Q: What is an access network?
A: A network connecting an end system to an edge router.
Q: What are guided media?
A: Media where signals travel through a physical medium.
Q: Give examples of guided media.
A: Copper, fibre and coax.
Q: Give an example of unguided media.
A: Radio.
Q: What is packet switching?
A: Breaking messages into packets and forwarding them through routers.
Q: What is store-and-forward?
A: A router receives the entire packet before sending it onto the next link.
Q: What is transmission delay?
A: \(L/R\).
Q: What happens if packet arrival rate exceeds transmission rate?
A: Packets queue and may eventually be dropped.
Q: What is forwarding?
A: Local movement of a packet from an input link to an output link.
Q: What is routing?
A: Determining the overall source-to-destination path.
Q: What is circuit switching?
A: Reserving dedicated resources for a communication session.
Q: What does FDM divide?
A: Frequency.
Q: What does TDM divide?
A: Time.
Q: What is an IXP?
A: Internet Exchange Point, infrastructure for interconnecting networks.
Q: What is peering?
A: Direct connection between networks to exchange traffic.
Q: How many bits are in one byte?
A: 8.
---
📕 SYLLABUS / EXAM GUIDE
The module catalogue is especially useful because it tells us what your lecturer expects you to be able to do. Weeks 1–4 are explicitly:
Week 1: Introduction to Computer Networks
Week 2: Computer Network Models
Week 3: IP Addressing and Subnetting
Week 4: The Internet — protocols, network edge, network core
The module's stated learning outcomes include understanding computer communication, networking devices, OSI/TCP-IP models, transmission modes, network sizes, topologies, Internet components and application protocols.
The module also explicitly expects students to compute throughput, link utilization and delays, and later covers TCP/UDP, routing, QoS and congestion control.
The assessment information says the written examination is 60%, with a 3-hour paper, while continuous assessment is 40%.
---
🔥 TOP 30 THINGS I WOULD MEMORISE FIRST
If you're short on time, learn these first:
1. Computer network definition
2. MAC vs IP vs Port
3. Hub vs Switch
4. Router
5. Simplex
6. Half-duplex
7. Full-duplex
8. Client/server
9. P2P
10. PAN/LAN/MAN/WAN
11. CIA
12. Layered architecture advantages
13. Service vs protocol vs interface
14. Seven OSI layers
15. Function of every OSI layer
16. Four TCP/IP layers
17. TCP vs UDP
18. IP
19. ARP
20. ICMP
21. IPv4 header fields
22. Fragmentation
23. NetID/HostID
24. Subnetting
25. Subnet mask: 1 = network, 0 = host
26. CIDR /n
27. NAT
28. Protocol definition
29. Network edge vs network core
30. Transmission delay = L/R
🧩 Most important formulas/concepts
\[
\boxed{d_{trans}=\frac{L}{R}}
\]
\[
\boxed{\text{Host bits}=32-\text{prefix length}}
\]
\[
\boxed{1\text{ Byte}=8\text{ bits}}
\]
And remember:
> OSI: Physical → Data Link → Network → Transport → Session → Presentation → Application
> TCP/IP: Network Interface → Internet → Transport → Application
This gives you a solid Weeks 1–4 revision pack directly from the uploaded lecture material and syllabus.