Year 7 · Autumn 2
Networks · Lesson 1 of 5
Semaphore and Morse: what a protocol is
UnpluggedTopic 15 Networks and the internet
Year 7 · Networks · Lesson 1 of 5
You will learn to
- Explain what a protocol is: rules that both sides agree before they communicate.
- Use a simple code, like Morse, to send a word across the room.
- Identify why a message fails when the two sides follow different rules.
Year 7 · Networks · Lesson 1 of 5
Success criteria
You have got it when you can say:
- I can send and receive a short word using the class's agreed code.
- I can say what went wrong when our first try failed.
- I can explain the word 'protocol' in one sentence.
Year 7 · Networks · Lesson 1 of 5
Retrieval starter
Questions from before. Write your answers, then show them.
- Last unit
Logging into a friend's account 'just to look' is…
A Against the Computer Misuse ActB Fine if you don't change anything
A. Against the Computer Misuse Act
- Last unit
Most of a smartphone's lifetime carbon footprint comes from…
A Recycling itB Charging itC Making it
C. Making it
- Last unit
Spreading ransomware that locks a company's files is which CMA offence?
A Section 1B Section 3C Section 2
B. Section 3
Year 7 · Networks · Lesson 1 of 5
Key words (1 of 2)
- protocol
- A set of agreed rules for communication.
- LAN / WAN
- Local Area Network: a network over a small area.
- Router
- Connects different networks and forwards packets.
- IP address
- A device's address on a network. IPv4 = 4 bytes.
Year 7 · Networks · Lesson 1 of 5
Key words (2 of 2)
- MAC address
- Fixed unique ID of a network card. 48 bits in hex.
- DNS
- Domain Name System: turns website names into IP addresses.
- Packet
- A small numbered chunk of data sent across a network.
- Bandwidth / latency
- How much data a connection can carry per second.
The explanation · step 1 of 1 · part 1 of 2
Protocols
A protocol is a set of agreed rules for communicating.
| Protocol | Job |
|---|---|
| TCP | Splits into packets, numbers them, checks they all arrive |
| IP | Addresses and routes packets |
| HTTP / HTTPS | Fetches web pages (HTTPS is encrypted) |
| DNS | Turns names into IP addresses |
| SMTP | Sends email |
| IMAP / POP | Collects email |
| FTP | Transfers files |
The explanation · step 1 of 1 · part 2 of 2
Protocols (continued)
Protocols work in layers, each with one job. Wi-Fi or cable, the web page doesn't care.
Year 7 · Networks · Lesson 1 of 5
Quick quiz · 1 of 3
Why can't an IPv4 part be 300?
- A 300 is reserved
- B Each part is one byte: max 255
- C Routers can't count that high
B. Each part is one byte: max 255
8 bits hold 0 to 255.
Year 7 · Networks · Lesson 1 of 5
Quick quiz · 2 of 3
Which turns www.bbc.co.uk into an IP address?
- A DNS
- B SMTP
- C HTTP
A. DNS
DNS is the phone book.
Year 7 · Networks · Lesson 1 of 5
Quick quiz · 3 of 3
Packets arrive out of order. How are they fixed?
- A They're sent again
- B The router sorts them
- C Sequence numbers
C. Sequence numbers
The receiver puts them back in order by number.
Year 7 · Networks · Lesson 1 of 5
Exit ticket
Answer on paper before you go. Then check.
Which device joins your home LAN to your ISP's network?
A Wireless access pointB SwitchC Router
C. Router A router joins different networks. A switch only joins devices inside one LAN.
In a star network the central switch breaks. What happens?
A Only one device drops offB Data finds another routeC Every device loses the network
C. Every device loses the network The switch is a single point of failure: everything goes through it.