tcp/ip model
4 detailed 50-minute lessons with teaching scripts, worked examples, parent guides, and assessment criteria.
Lesson Overview
Total Lessons: 4
Tier: Foundation and Higher
Duration: 50 minutes per lesson (200 minutes total)
Exam Boards: AQA, Edexcel, OCR, Eduqas, CCEA
Tier: Foundation and Higher
Duration: 50 minutes per lesson (200 minutes total)
Exam Boards: AQA, Edexcel, OCR, Eduqas, CCEA
Learning Objectives
- Explain the key ideas of tcp/ip model
- Apply tcp/ip model to exam-style questions
- Develop independent study skills
- Build cross-topic connections
Prerequisites
- Read the revision notes for tcp/ip model first (GCSE Revise summary)
- Key vocab to pre-teach: Function, Function, Function
- Basic skills: reading the summary notes and answering the practice questions there
Materials & Equipment
- Exercise book, coloured pens
- Ruler
- Printed revision notes (link below)
- Internet for videos (see Resources)
Lesson 1: Introduction: tcp/ip model
Duration: 50 minutes
Starter Activity (5 minutes)
Quick Recall
Write down everything you already know about tcp/ip model. Then check against the key terms: Function, Function, Function. Use a mini-whiteboard or paper.
Main Content (35 minutes)
Parent/Teacher Guide:
Before lesson: Read the script below. Pre-teach key vocab: Function, Function, Function.
If stuck: Re-read the revision notes (link above), then break the content into smaller steps.
Extension: See the Stretch & Challenge ideas in Lesson 4.
Before lesson: Read the script below. Pre-teach key vocab: Function, Function, Function.
If stuck: Re-read the revision notes (link above), then break the content into smaller steps.
Extension: See the Stretch & Challenge ideas in Lesson 4.
Teaching Script (35 mins):
Mins 0-5 - Hook: "Today: tcp/ip model. By the end you will be able to answer exam questions on it unaided. It connects to the rest of Computer Science because the ideas here recur across the spec."
Mins 5-20 - Direct Instruction: Work through the core ideas below one at a time; after each, ask your student to explain it back in their own words.
Mins 20-30 - Guided Practice: Model the worked example together, then let your student attempt the first practice question with guidance.
Mins 30-35 - Independent Practice: 2-3 practice questions from Lesson 3 below, with immediate feedback.
Mins 0-5 - Hook: "Today: tcp/ip model. By the end you will be able to answer exam questions on it unaided. It connects to the rest of Computer Science because the ideas here recur across the spec."
Mins 5-20 - Direct Instruction: Work through the core ideas below one at a time; after each, ask your student to explain it back in their own words.
Mins 20-30 - Guided Practice: Model the worked example together, then let your student attempt the first practice question with guidance.
Mins 30-35 - Independent Practice: 2-3 practice questions from Lesson 3 below, with immediate feedback.
First Look
Start with the revision notes summary, then attempt: Name the four layers of the TCP/IP model from top to bottom and state the main function of each.
Plenary (5 minutes)
Check Out
Your student states one thing they learned and one question they still have about tcp/ip model.
Lesson 2: Core Concepts: tcp/ip model
Duration: 50 minutes
Starter Activity (5 minutes)
Review Previous Lesson
Quick recap: write 3 key points from Lesson 1 on tcp/ip model. Check them against the notes below.
Main Content (35 minutes)
Definition: The TCP/IP model is a conceptual framework that describes how data is transmitted over a network. It divides network communication into four layers, each with a specific role. Data passes down through the layers when being sent, and up through the layers when being received.
Function: The application layer provides network services directly to user applications. It is the layer that users interact with most directly. It determines what data is sent and how it is formatted for the application.
Function: The transport layer manages end-to-end communication between two devices. It ensures data is delivered reliably (TCP) or quickly (UDP), breaks data into segments, and handles flow control.
Function: The internet layer handles addressing and routing of data packets across networks. It adds IP addresses to identify the source and destination, and determines the best route for packets to take across interconnected networks.
Function: The link layer handles the physical transmission of data on a local network segment. It is responsible for getting data from one device to the next on the same network, using MAC addresses and physical media.
Definition: Encapsulation is the process where each layer adds its own header (control information) to the data as it passes down the layers. When data is received, each layer removes its header (decapsulation) as it passes up the layers.
| Term | Meaning | Example |
|---|---|---|
| 4 (Top) | Application | HTTP, HTTPS, SMTP, IMAP, FTP |
| 3 | Transport | TCP, UDP |
| 2 | Internet | IP |
| 1 (Bottom) | Link | Ethernet, Wi-Fi |
| Connection | Connection-oriented (establishes connection first) | Connectionless (just sends data) |
| Reliability | Reliable (acks, resends lost data) | Unreliable (no guarantee of delivery) |
| Ordering | Ordered (reassembles in sequence) | Not ordered (arrives in any order) |
| Speed | Slower (overhead of checks) | Faster (no overhead) |
Practice (10 minutes)
Q: Name the four layers of the TCP/IP model from top to bottom and state the main function of each.
Answer: Application (top): provides network services to applications (HTTP, SMTP). Transport: manages end-to-end delivery, reliability, and segmentation (TCP, UDP). Internet: handles addressing and routing across networks (IP). Link (bottom): handles physical transmission on the local network (Ethernet, Wi-Fi).
Plenary (5 minutes)
Explain Back
Your student teaches the key points back to you without looking. Fill any gaps immediately.
Lesson 3: Application: tcp/ip model
Duration: 50 minutes
Starter Activity (5 minutes)
Quick Recall
Recall the key terms: Function, Function, Function. Define each in one sentence.
Main Content (35 minutes)
Parent/Teacher Guide: Let your student attempt each question alone first, then compare with the model answer. Award method marks for correct working even if the final answer is wrong.
Q1: Name the four layers of the TCP/IP model from top to bottom and state the main function of each.
Answer: Application (top): provides network services to applications (HTTP, SMTP). Transport: manages end-to-end delivery, reliability, and segmentation (TCP, UDP). Internet: handles addressing and routing across networks (IP). Link (bottom): handles physical transmission on the local network (Ethernet, Wi-Fi).
Q2: Explain the difference between TCP and UDP at the transport layer. Give an example of when each would be used.
Answer: TCP is connection-oriented, reliable (uses acknowledgements and resends lost data), and ordered. UDP is connectionless, unreliable (no guarantees), and faster. TCP is used for web browsing and email where all data must arrive. UDP is used for live video streaming and online gaming where speed matters more than perfect delivery.
Q3: Describe the process of encapsulation as data is sent down the layers.
Answer: Encapsulation: the application layer creates data and passes it down. The transport layer adds a header with port numbers (creating a segment). The internet layer adds an IP header with source and destination addresses (creating a packet). The link layer adds a frame header with MAC addresses and a frame trailer for error checking (creating a frame). Each layer wraps the data from above with its own control information.
Q4: Which layer of the TCP/IP model handles routing of data across networks? Which protocol operates at this layer?
Answer: The Internet layer handles routing of data across networks. The Internet Protocol (IP) operates at this layer, adding source and destination IP addresses to packets and determining the best route for them.
Q5: Explain why the TCP/IP model uses layers rather than having a single protocol handle everything.
Answer: Layers allow each aspect of communication to be developed independently. A change at one layer (e.g. switching from Wi-Fi to Ethernet at the link layer) doesn't affect other layers. Layers make the model modular, easier to understand, and allow different technologies to work together. Without layers, a single protocol would need to handle everything from physical signals to application formatting, which would be extremely complex.
Plenary (5 minutes)
Error Review
Review any questions answered incorrectly. Identify whether the error was knowledge, method, or reading the question.
Lesson 4: Exam Practice: tcp/ip model
Duration: 50 minutes
Starter Activity (5 minutes)
Command Words
Review what these command words require: state (one point), describe (say what happens), explain (say why), compare (both sides), evaluate (judgement).
Main Content (35 minutes)
Extended Answer
Extended question: Full-Mark Response Describe the four layers of the TCP/IP model, explaining the role of each layer and giving one protocol that operates at each layer. [4 marks] <div class="
Application layer: Provides the interface for user applications and handles high-level protocols. Formats data for the user and manages application-level communication. Protocol: HTTP (web browsing). Transport layer: Manages end-to-end communication between applications, ensuring data is delivered reliably or quickly depending on the protocol. Handles port addressing and error checking. Protocol: TCP (reliable delivery with error checking). Internet layer: Handles logical addressing (IP addresses) and routing of packets across networks. Determines the best path for data to travel from source to destination. Protocol: IP (Internet Protocol for addressing and routing). Link layer: Manages physical transmission of data over the network medium. Handles hardware addressing (MAC addresses), framing, and error detection at the physical level. Protocol: Ethernet (wired LAN transmission).
Exam Tips: Know all four layers in order: Application, Transport, Internet, Link | Be able to name the key protocol(s) at each layer | Understand encapsulation: each layer adds a header going down, removes it going up | Know when TCP vs UDP is appropriate (reliability vs speed) | Remember: IP = Internet layer, HTTP/SMTP = Application layer, Ethernet/Wi-Fi = Link layer | The link layer is the ONLY layer that adds a trailer (for error checking)
Common Errors: ✗ Confusing the TCP/IP model with the OSI model ✓ TCP/IP has 4 layers (Application, Transport, Internet, Link). OSI has 7 layers. TCP/IP is the practical model used on the internet; OSI is the theoretical reference model. ✗ Thinking data is sent as a single block across the network ✓ Data is broken into packets, each with headers containing source/destination IP, port numbers, and sequence numbers. Packets may take different routes and are reassembled at the destination. ✗ Forgetting that each layer adds its own header to the packet ✓ As data passes down the layers, each layer encapsulates it with its own header (Application → Transport → Internet → Link). At the destination, each layer stri
Stretch & Challenge (Grade 8-9):
- Synoptic links: explain how tcp/ip model connects to another Computer Science topic you have studied
- Real-world: research one real-world use or example of tcp/ip model
- Critical: "What are the limitations of the models used in tcp/ip model?"
Plenary (5 minutes)
Assessment Criteria
- Got it: Confident explanation + correct worked examples
- Getting there: Main points OK, needs support with detail
- Not yet: Confused on key concepts - re-run Lesson 2
Homework & Consolidation
- Consolidation: Re-answer any Lesson 3 practice questions answered incorrectly (20 mins)
- Retrieval: Write flashcards for the key terms: Function, Function, Function (10 mins)
- Exam practice: One past-paper question on tcp/ip model from the board websites (15 mins)
- Extension: Explain tcp/ip model to someone else in your own words (10 mins)