Packets and numbered message parts
A packet carries data plus information for handling it. This classroom model uses a destination and a numbered position within one message
- Read the destination The sender tells us where a packet came from. The destination tells us which device should receive it. Keep records for the named destination
- Use the part number Arrival 1 means first to arrive. Part 1 means first in the message. Those positions need not match
- Keep one copy of each part An identical repeat of part 1 still gives only part 1. It does not fill part 2. Equal data in different numbered parts is not a duplicate part
- Leave missing data missing Compare the received part numbers with the expected positions. Do not borrow from another destination or guess from a familiar sentence
Worked example
Each device expects one separate message. The table shows arrivals. Device T expects parts 1 to 4. Keep only destination T; ignore an identical repeated part
| Arrival | Destination | Part | Data |
|---|---|---|---|
| 1 | T | 4 | BOX |
| 2 | T | 2 | 6 |
| 3 | S | 1 | TIN |
| 4 | T | 1 | RED |
| 5 | T | 2 | 6 |
| 6 | T | 3 | CLAY |
Which result follows when the received data chunks are put in part-number order, separated by spaces? Do not guess missing data
Keep destination T: arrivals 1, 2, 4, 5 and 6. Other destinations belong to other devices' messages
The distinct received part numbers are 1, 2, 3 and 4. Ignore 1 identical duplicate
Part 1: RED; Part 2: 6; Part 3: CLAY; Part 4: BOX
Answer: RED 6 CLAY BOX
Common mistakes
Difficulty levels
Questions about this topic
Is a packet the same as one bit?+
No. A packet carries data and handling information. A bit is one binary digit. Dividing a message into packets also does not, by itself, compress its data
Does every real network use part numbers like these?+
No. This is a small model for learning about order and missing data. Real protocols use different fields and methods, and the expected count here comes from the task
Are the practice cases unlimited?+
No. This bank has 24 fixed cases, eight per tier. A shuffled answer order is not a new case; repeated attempts record practice rather than fresh mastery evidence
Does this assess a network project or my own program?+
No. These tasks check choices about supplied records. Designing, implementing, investigating and explaining your own solution require additional practical and written evidence
Can I use a calculator?+
No. This topic is practised without a calculator
Which year level and chapter is this?+
Year 7 Digital Technologies, chapter 1: Digital systems