← IGCSE Computer Science Paper 1

Packet payload

The part of a packet that carries the actual data being sent, such as a piece of a file or message. The header and trailer are not payload.

Part of: IGCSE Computer Science 0478 — 2.1 Data Transmission Types and Methods — Module 12, ACARA Digital Technologies Years 7–8 — Wired and Wireless Networks — Module 44

Understanding Packet payload in IGCSE Computer Science Paper 1

What it does: The text in the payload is a piece of the message being sent. It is the real content, not delivery information. The destination address and packet number are in the header and help deliver the packet. Only the data part is the payload.

Common mistakes: The payload carries a piece of the actual file or message. The destination address belongs in the header, so this line should be: payload ← piece of the file. The payload holds the data being sent, such as a part of a file. Addresses are in the header, so this line should be: SET payload TO file_part.

Class: _____________________  ·  Name: _____________________  ·  Date: _________

Free printable worksheet with full answer key — or add this module to a class and your students practise it interactively.

🖨 Print worksheet + answer key Add Packet payload to a class →

This module's key terms are also in a printable crossword (Modules 110–120) and word search (Modules 86–120).

Take this worksheet further — free with Cloodit

Each concept is reinforced from every angle — learned, then applied, then tested.

Learning
Duo
Which part of a packet carries the actual data being sent?
The headerThe payload
Matches
payload = destination IP address and packet number
↓
The destination address and packet number belong in the header, not the payload. The payload is the actual data being sent.
Applying
Meanings
Term
payload
Meaning
The part of a packet that carries the actual data being sent, such as a piece of a file or message. The header and trailer are not payload.
Practice
PACKET 3 of 8
Testing
Gaps
packet = header + + trailer
Check Answer
Spots
1payload ← destination address
2header ← destination, number

Cloodit turns curriculum-aligned coding content into journeys students work through one biome at a time.

The 'Starfish' badge — Five-Point Star, one of Cloodit's 106 collectible badges
Students earn collectable badges

Over 100 of them, across seven natural biomes.

Study Buddy
Students build a real study resource

Turns their work into revision material ready for Flash Cards and Exam study.

Diamond Dash — one of Cloodit's live, competitive Sprint games
Students lock in with Sprints

Live, competitive practice for the start of the lesson or a teacher-led lesson finisher.

A Cloodit certificate of achievement, ready to personalise and print
Custom printable certificates

Honour your top performers, or encourage a student who's trying hard — ready to print in seconds.

Add to class →

Quick Questions

1. Which part of a packet carries the actual data being sent?
A. The header
B. The payload ✓
The payload is the part of the packet that carries the actual data. The header holds information such as the addresses and packet number.
2. What does the payload of a packet contain?
A. A piece of the file or message being sent ✓
B. The destination address and packet number
The payload holds a piece of the file or message. Addresses and the packet number are in the header.
3. Is the packet header part of the payload?
A. No, the header is not payload ✓
B. Yes, the header is part of the payload
The header and trailer are not payload. They only help the packet reach its destination and be checked.
4. A 5 MB photo is split into packets. What does the payload of one packet hold?
A. A small piece of the photo's data ✓
B. The whole photo every time
Each packet's payload carries only one piece of the file. The destination puts all the pieces back together.
5. Which of these is NOT payload?
A. A piece of an email message
B. The packet trailer ✓
The trailer marks the end of the packet and is not payload. A piece of an email message is exactly what the payload carries.

Match the Pairs

payload → The part of a packet that carries the actual data being sent
payload = piece of file → The payload holds just one piece of a larger file or message, not the whole thing
The payload is the actual data, such as part of an email, carried inside one packet → Packet 3: payload = "Hello, how are"
The header and trailer are not the payload because they only help deliver the packet → header: dest=192.168.1.5, packet no=3 | payload: data
payload = destination IP address and packet number → The destination address and packet number belong in the header, not the payload. The payload is the actual data being sent.
payload = the whole 5 MB file in one packet → A payload holds only a small piece of the file. A large file is split across many packets, each with its own payload.

Key Term

payload
The part of a packet that carries the actual data being sent, such as a piece of a file or message. The header and trailer are not payload.

Fill in the Blanks

1. packet = header + payload + trailer
Hint: Type the name of the middle part of the packet that carries the actual data being sent.
2. payload = "piece of a file"
Hint: Type the variable name for the part of the packet that holds the data being sent.
3. OUTPUT packet.payload
Hint: Type the field name that gives the actual data carried by the packet.
4. headerIsPayload = False
Hint: Type the Boolean value that shows whether a header counts as payload.
5. packet = header + payload + trailer
Hint: Type the last part of the packet, which comes after the data and is not payload.

Spot the Error

Question 1
A payload ← destination address
B header ← destination, number
C trailer ← end of packet
Line A — The payload carries a piece of the actual file or message. The destination address belongs in the header, so this line should be: payload ← piece of the file.
Question 2
A SET payload TO dest_address
B SET header TO addresses
C SET trailer TO end_marker
Line A — The payload holds the data being sent, such as a part of a file. Addresses are in the header, so this line should be: SET payload TO file_part.
Question 3
A packet.header = dest, src, no
B packet.payload = 'Hel'
C packet.trailer = file_data
Line C — The trailer only marks the end of the packet. The file data is carried in the payload, so this line should be: packet.trailer = end_marker.
Question 4
A PACKET 3 OF 10
B PAYLOAD = packet number 3
C HEADER = dest, source, number
D TRAILER = end of packet
Line B — The packet number is stored in the header. The payload carries part of the message, so this line should be: PAYLOAD = part of the message.
Question 5
A IF packet arrives THEN
B read header
C read payload
D store trailer in the file
E ENDIF
Line D — The file is rebuilt from the payloads. The trailer is not file data, so this line should be: store payload in the file.

Student with a class code? Join your class →